Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

155 files changed, 28213 insertions, 0 deletions

diff --git a/storage/BaseVFS.cpp b/storage/BaseVFS.cpp
new file mode 100644
index 0000000000..f6090bf008
--- /dev/null
+++ b/storage/BaseVFS.cpp
@@ -0,0 +1,265 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "BaseVFS.h"
+
+#include <string.h>
+#include "sqlite3.h"
+#include "mozilla/net/IOActivityMonitor.h"
+
+namespace {
+
+// The last VFS version for which this file has been updated.
+constexpr int kLastKnowVfsVersion = 3;
+
+// The last io_methods version for which this file has been updated.
+constexpr int kLastKnownIOMethodsVersion = 3;
+
+using namespace mozilla;
+using namespace mozilla::net;
+
+struct BaseFile {
+  // Base class.  Must be first
+  sqlite3_file base;
+  // The filename
+  char* location;
+  // This points to the underlying sqlite3_file
+  sqlite3_file pReal[1];
+};
+
+int BaseClose(sqlite3_file* pFile) {
+  BaseFile* p = (BaseFile*)pFile;
+  delete[] p->location;
+  return p->pReal->pMethods->xClose(p->pReal);
+}
+
+int BaseRead(sqlite3_file* pFile, void* zBuf, int iAmt, sqlite_int64 iOfst) {
+  BaseFile* p = (BaseFile*)pFile;
+  int rc = p->pReal->pMethods->xRead(p->pReal, zBuf, iAmt, iOfst);
+  if (rc == SQLITE_OK && IOActivityMonitor::IsActive()) {
+    IOActivityMonitor::Read(nsDependentCString(p->location), iAmt);
+  }
+  return rc;
+}
+
+int BaseWrite(sqlite3_file* pFile, const void* zBuf, int iAmt,
+              sqlite_int64 iOfst) {
+  BaseFile* p = (BaseFile*)pFile;
+  int rc = p->pReal->pMethods->xWrite(p->pReal, zBuf, iAmt, iOfst);
+  if (rc == SQLITE_OK && IOActivityMonitor::IsActive()) {
+    IOActivityMonitor::Write(nsDependentCString(p->location), iAmt);
+  }
+  return rc;
+}
+
+int BaseTruncate(sqlite3_file* pFile, sqlite_int64 size) {
+  BaseFile* p = (BaseFile*)pFile;
+  return p->pReal->pMethods->xTruncate(p->pReal, size);
+}
+
+int BaseSync(sqlite3_file* pFile, int flags) {
+  BaseFile* p = (BaseFile*)pFile;
+  return p->pReal->pMethods->xSync(p->pReal, flags);
+}
+
+int BaseFileSize(sqlite3_file* pFile, sqlite_int64* pSize) {
+  BaseFile* p = (BaseFile*)pFile;
+  return p->pReal->pMethods->xFileSize(p->pReal, pSize);
+}
+
+int BaseLock(sqlite3_file* pFile, int eLock) {
+  BaseFile* p = (BaseFile*)pFile;
+  return p->pReal->pMethods->xLock(p->pReal, eLock);
+}
+
+int BaseUnlock(sqlite3_file* pFile, int eLock) {
+  BaseFile* p = (BaseFile*)pFile;
+  return p->pReal->pMethods->xUnlock(p->pReal, eLock);
+}
+
+int BaseCheckReservedLock(sqlite3_file* pFile, int* pResOut) {
+  BaseFile* p = (BaseFile*)pFile;
+  return p->pReal->pMethods->xCheckReservedLock(p->pReal, pResOut);
+}
+
+int BaseFileControl(sqlite3_file* pFile, int op, void* pArg) {
+#if defined(MOZ_SQLITE_PERSIST_AUXILIARY_FILES)
+  // Persist auxiliary files (-shm and -wal) on disk, because creating and
+  // deleting them may be expensive on slow storage.
+  // Only do this when there is a journal size limit, so the journal is
+  // truncated instead of deleted on shutdown, that feels safer if the user
+  // moves a database file around without its auxiliary files.
+  MOZ_ASSERT(
+      ::sqlite3_compileoption_used("DEFAULT_JOURNAL_SIZE_LIMIT"),
+      "A journal size limit ensures the journal is truncated on shutdown");
+  if (op == SQLITE_FCNTL_PERSIST_WAL) {
+    *static_cast<int*>(pArg) = 1;
+    return SQLITE_OK;
+  }
+#endif
+  BaseFile* p = (BaseFile*)pFile;
+  return p->pReal->pMethods->xFileControl(p->pReal, op, pArg);
+}
+
+int BaseSectorSize(sqlite3_file* pFile) {
+  BaseFile* p = (BaseFile*)pFile;
+  return p->pReal->pMethods->xSectorSize(p->pReal);
+}
+
+int BaseDeviceCharacteristics(sqlite3_file* pFile) {
+  BaseFile* p = (BaseFile*)pFile;
+  return p->pReal->pMethods->xDeviceCharacteristics(p->pReal);
+}
+
+int BaseShmMap(sqlite3_file* pFile, int iPg, int pgsz, int bExtend,
+               void volatile** pp) {
+  BaseFile* p = (BaseFile*)pFile;
+  return p->pReal->pMethods->xShmMap(p->pReal, iPg, pgsz, bExtend, pp);
+}
+
+int BaseShmLock(sqlite3_file* pFile, int offset, int n, int flags) {
+  BaseFile* p = (BaseFile*)pFile;
+  return p->pReal->pMethods->xShmLock(p->pReal, offset, n, flags);
+}
+
+void BaseShmBarrier(sqlite3_file* pFile) {
+  BaseFile* p = (BaseFile*)pFile;
+  return p->pReal->pMethods->xShmBarrier(p->pReal);
+}
+
+int BaseShmUnmap(sqlite3_file* pFile, int deleteFlag) {
+  BaseFile* p = (BaseFile*)pFile;
+  return p->pReal->pMethods->xShmUnmap(p->pReal, deleteFlag);
+}
+
+int BaseFetch(sqlite3_file* pFile, sqlite3_int64 iOfst, int iAmt, void** pp) {
+  BaseFile* p = (BaseFile*)pFile;
+  return p->pReal->pMethods->xFetch(p->pReal, iOfst, iAmt, pp);
+}
+
+int BaseUnfetch(sqlite3_file* pFile, sqlite3_int64 iOfst, void* pPage) {
+  BaseFile* p = (BaseFile*)pFile;
+  return p->pReal->pMethods->xUnfetch(p->pReal, iOfst, pPage);
+}
+
+int BaseOpen(sqlite3_vfs* vfs, const char* zName, sqlite3_file* pFile,
+             int flags, int* pOutFlags) {
+  BaseFile* p = (BaseFile*)pFile;
+  if (zName) {
+    p->location = new char[7 + strlen(zName) + 1];
+    strcpy(p->location, "file://");
+    strcpy(p->location + 7, zName);
+  } else {
+    p->location = new char[8];
+    strcpy(p->location, "file://");
+  }
+
+  sqlite3_vfs* origVfs = (sqlite3_vfs*)(vfs->pAppData);
+  int rc = origVfs->xOpen(origVfs, zName, p->pReal, flags, pOutFlags);
+  if (rc) {
+    return rc;
+  }
+  if (p->pReal->pMethods) {
+    // If the io_methods version is higher than the last known one, you should
+    // update this VFS adding appropriate IO methods for any methods added in
+    // the version change.
+    MOZ_ASSERT(p->pReal->pMethods->iVersion == kLastKnownIOMethodsVersion);
+    static const sqlite3_io_methods IOmethods = {
+        kLastKnownIOMethodsVersion, /* iVersion */
+        BaseClose,                  /* xClose */
+        BaseRead,                   /* xRead */
+        BaseWrite,                  /* xWrite */
+        BaseTruncate,               /* xTruncate */
+        BaseSync,                   /* xSync */
+        BaseFileSize,               /* xFileSize */
+        BaseLock,                   /* xLock */
+        BaseUnlock,                 /* xUnlock */
+        BaseCheckReservedLock,      /* xCheckReservedLock */
+        BaseFileControl,            /* xFileControl */
+        BaseSectorSize,             /* xSectorSize */
+        BaseDeviceCharacteristics,  /* xDeviceCharacteristics */
+        BaseShmMap,                 /* xShmMap */
+        BaseShmLock,                /* xShmLock */
+        BaseShmBarrier,             /* xShmBarrier */
+        BaseShmUnmap,               /* xShmUnmap */
+        BaseFetch,                  /* xFetch */
+        BaseUnfetch                 /* xUnfetch */
+    };
+    pFile->pMethods = &IOmethods;
+  }
+
+  return SQLITE_OK;
+}
+
+}  // namespace
+
+namespace mozilla::storage::basevfs {
+
+const char* GetVFSName(bool exclusive) {
+  return exclusive ? "base-vfs-excl" : "base-vfs";
+}
+
+UniquePtr<sqlite3_vfs> ConstructVFS(bool exclusive) {
+#if defined(XP_WIN)
+#  define EXPECTED_VFS "win32"
+#  define EXPECTED_VFS_EXCL "win32"
+#else
+#  define EXPECTED_VFS "unix"
+#  define EXPECTED_VFS_EXCL "unix-excl"
+#endif
+
+  if (sqlite3_vfs_find(GetVFSName(exclusive))) {
+    return nullptr;
+  }
+
+  bool found;
+  sqlite3_vfs* origVfs;
+  if (!exclusive) {
+    // Use the non-exclusive VFS.
+    origVfs = sqlite3_vfs_find(nullptr);
+    found = origVfs && origVfs->zName && !strcmp(origVfs->zName, EXPECTED_VFS);
+  } else {
+    origVfs = sqlite3_vfs_find(EXPECTED_VFS_EXCL);
+    found = (origVfs != nullptr);
+  }
+  if (!found) {
+    return nullptr;
+  }
+
+  // If the VFS version is higher than the last known one, you should update
+  // this VFS adding appropriate methods for any methods added in the version
+  // change.
+  MOZ_ASSERT(origVfs->iVersion == kLastKnowVfsVersion);
+
+  sqlite3_vfs vfs = {
+      kLastKnowVfsVersion,                                    /* iVersion  */
+      origVfs->szOsFile + static_cast<int>(sizeof(BaseFile)), /* szOsFile */
+      origVfs->mxPathname,                                    /* mxPathname */
+      nullptr,                                                /* pNext */
+      GetVFSName(exclusive),                                  /* zName */
+      origVfs,                                                /* pAppData */
+      BaseOpen,                                               /* xOpen */
+      origVfs->xDelete,                                       /* xDelete */
+      origVfs->xAccess,                                       /* xAccess */
+      origVfs->xFullPathname,     /* xFullPathname */
+      origVfs->xDlOpen,           /* xDlOpen */
+      origVfs->xDlError,          /* xDlError */
+      origVfs->xDlSym,            /* xDlSym */
+      origVfs->xDlClose,          /* xDlClose */
+      origVfs->xRandomness,       /* xRandomness */
+      origVfs->xSleep,            /* xSleep */
+      origVfs->xCurrentTime,      /* xCurrentTime */
+      origVfs->xGetLastError,     /* xGetLastError */
+      origVfs->xCurrentTimeInt64, /* xCurrentTimeInt64 */
+      origVfs->xSetSystemCall,    /* xSetSystemCall */
+      origVfs->xGetSystemCall,    /* xGetSystemCall */
+      origVfs->xNextSystemCall    /* xNextSystemCall */
+  };
+
+  return MakeUnique<sqlite3_vfs>(vfs);
+}
+
+}  // namespace mozilla::storage::basevfs
diff --git a/storage/BaseVFS.h b/storage/BaseVFS.h
new file mode 100644
index 0000000000..f900bc5d21
--- /dev/null
+++ b/storage/BaseVFS.h
@@ -0,0 +1,30 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef STORAGE_BASEVFS_H_
+#define STORAGE_BASEVFS_H_
+
+#include "mozilla/UniquePtr.h"
+
+struct sqlite3_vfs;
+struct sqlite3_file;
+
+template <typename T>
+struct already_AddRefed;
+
+namespace mozilla::dom::quota {
+class QuotaObject;
+}
+
+namespace mozilla::storage::basevfs {
+
+const char* GetVFSName(bool exclusive);
+
+UniquePtr<sqlite3_vfs> ConstructVFS(bool exclusive);
+
+}  // namespace mozilla::storage::basevfs
+
+#endif  // STORAGE_OBFUSCATINGVFS_H_
diff --git a/storage/FileSystemModule.cpp b/storage/FileSystemModule.cpp
new file mode 100644
index 0000000000..df756838f8
--- /dev/null
+++ b/storage/FileSystemModule.cpp
@@ -0,0 +1,254 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "FileSystemModule.h"
+
+#include "sqlite3.h"
+#include "nsComponentManagerUtils.h"
+#include "nsString.h"
+#include "nsIDirectoryEnumerator.h"
+#include "nsIFile.h"
+
+namespace {
+
+struct VirtualTableCursorBase {
+  VirtualTableCursorBase() { memset(&mBase, 0, sizeof(mBase)); }
+
+  sqlite3_vtab_cursor mBase;
+};
+
+struct VirtualTableCursor : public VirtualTableCursorBase {
+ public:
+  VirtualTableCursor() : mRowId(-1) { mCurrentFileName.SetIsVoid(true); }
+
+  const nsString& DirectoryPath() const { return mDirectoryPath; }
+
+  const nsString& CurrentFileName() const { return mCurrentFileName; }
+
+  int64_t RowId() const { return mRowId; }
+
+  nsresult Init(const nsAString& aPath);
+  nsresult NextFile();
+
+ private:
+  nsCOMPtr<nsIDirectoryEnumerator> mEntries;
+
+  nsString mDirectoryPath;
+  nsString mCurrentFileName;
+
+  int64_t mRowId;
+};
+
+nsresult VirtualTableCursor::Init(const nsAString& aPath) {
+  nsCOMPtr<nsIFile> directory = do_CreateInstance(NS_LOCAL_FILE_CONTRACTID);
+  NS_ENSURE_TRUE(directory, NS_ERROR_FAILURE);
+
+  nsresult rv = directory->InitWithPath(aPath);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = directory->GetPath(mDirectoryPath);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = directory->GetDirectoryEntries(getter_AddRefs(mEntries));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = NextFile();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult VirtualTableCursor::NextFile() {
+  bool hasMore;
+  nsresult rv = mEntries->HasMoreElements(&hasMore);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (!hasMore) {
+    mCurrentFileName.SetIsVoid(true);
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsISupports> entry;
+  rv = mEntries->GetNext(getter_AddRefs(entry));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIFile> file = do_QueryInterface(entry);
+  NS_ENSURE_TRUE(file, NS_ERROR_FAILURE);
+
+  rv = file->GetLeafName(mCurrentFileName);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  mRowId++;
+
+  return NS_OK;
+}
+
+int Connect(sqlite3* aDB, void* aAux, int aArgc, const char* const* aArgv,
+            sqlite3_vtab** aVtab, char** aErr) {
+  static const char virtualTableSchema[] =
+      "CREATE TABLE fs ("
+      "name TEXT, "
+      "path TEXT"
+      ")";
+
+  int rc = sqlite3_declare_vtab(aDB, virtualTableSchema);
+  if (rc != SQLITE_OK) {
+    return rc;
+  }
+
+  sqlite3_vtab* vt = new sqlite3_vtab();
+  memset(vt, 0, sizeof(*vt));
+
+  *aVtab = vt;
+
+  return SQLITE_OK;
+}
+
+int Disconnect(sqlite3_vtab* aVtab) {
+  delete aVtab;
+
+  return SQLITE_OK;
+}
+
+int BestIndex(sqlite3_vtab* aVtab, sqlite3_index_info* aInfo) {
+  // Here we specify what index constraints we want to handle. That is, there
+  // might be some columns with particular constraints in which we can help
+  // SQLite narrow down the result set.
+  //
+  // For example, take the "path = x" where x is a directory. In this case,
+  // we can narrow our search to just this directory instead of the entire file
+  // system. This can be a significant optimization. So, we want to handle that
+  // constraint. To do so, we would look for two specific input conditions:
+  //
+  // 1. aInfo->aConstraint[i].iColumn == 1
+  // 2. aInfo->aConstraint[i].op == SQLITE_INDEX_CONSTRAINT_EQ
+  //
+  // The first states that the path column is being used in one of the input
+  // constraints and the second states that the constraint involves the equal
+  // operator.
+  //
+  // An even more specific search would be for name='xxx', in which case we
+  // can limit the search to a single file, if it exists.
+  //
+  // What we have to do here is look for all of our index searches and select
+  // the narrowest. We can only pick one, so obviously we want the one that
+  // is the most specific, which leads to the smallest result set.
+
+  for (int i = 0; i < aInfo->nConstraint; i++) {
+    if (aInfo->aConstraint[i].iColumn == 1 && aInfo->aConstraint[i].usable) {
+      if (aInfo->aConstraint[i].op & SQLITE_INDEX_CONSTRAINT_EQ) {
+        aInfo->aConstraintUsage[i].argvIndex = 1;
+      }
+      break;
+    }
+
+    // TODO: handle single files (constrained also by the name column)
+  }
+
+  return SQLITE_OK;
+}
+
+int Open(sqlite3_vtab* aVtab, sqlite3_vtab_cursor** aCursor) {
+  VirtualTableCursor* cursor = new VirtualTableCursor();
+
+  *aCursor = reinterpret_cast<sqlite3_vtab_cursor*>(cursor);
+
+  return SQLITE_OK;
+}
+
+int Close(sqlite3_vtab_cursor* aCursor) {
+  VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
+
+  delete cursor;
+
+  return SQLITE_OK;
+}
+
+int Filter(sqlite3_vtab_cursor* aCursor, int aIdxNum, const char* aIdxStr,
+           int aArgc, sqlite3_value** aArgv) {
+  VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
+
+  if (aArgc <= 0) {
+    return SQLITE_OK;
+  }
+
+  const char16_t* value =
+      static_cast<const char16_t*>(::sqlite3_value_text16(aArgv[0]));
+
+  nsDependentString path(value,
+                         ::sqlite3_value_bytes16(aArgv[0]) / sizeof(char16_t));
+
+  nsresult rv = cursor->Init(path);
+  NS_ENSURE_SUCCESS(rv, SQLITE_ERROR);
+
+  return SQLITE_OK;
+}
+
+int Next(sqlite3_vtab_cursor* aCursor) {
+  VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
+
+  nsresult rv = cursor->NextFile();
+  NS_ENSURE_SUCCESS(rv, SQLITE_ERROR);
+
+  return SQLITE_OK;
+}
+
+int Eof(sqlite3_vtab_cursor* aCursor) {
+  VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
+  return cursor->CurrentFileName().IsVoid() ? 1 : 0;
+}
+
+int Column(sqlite3_vtab_cursor* aCursor, sqlite3_context* aContext,
+           int aColumnIndex) {
+  VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
+
+  switch (aColumnIndex) {
+    // name
+    case 0: {
+      const nsString& name = cursor->CurrentFileName();
+      sqlite3_result_text16(aContext, name.get(),
+                            name.Length() * sizeof(char16_t), SQLITE_TRANSIENT);
+      break;
+    }
+
+    // path
+    case 1: {
+      const nsString& path = cursor->DirectoryPath();
+      sqlite3_result_text16(aContext, path.get(),
+                            path.Length() * sizeof(char16_t), SQLITE_TRANSIENT);
+      break;
+    }
+    default:
+      MOZ_ASSERT_UNREACHABLE("Unsupported column!");
+  }
+
+  return SQLITE_OK;
+}
+
+int RowId(sqlite3_vtab_cursor* aCursor, sqlite3_int64* aRowid) {
+  VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
+
+  *aRowid = cursor->RowId();
+
+  return SQLITE_OK;
+}
+
+}  // namespace
+
+namespace mozilla {
+namespace storage {
+
+int RegisterFileSystemModule(sqlite3* aDB, const char* aName) {
+  static sqlite3_module module = {
+      1,       Connect, Connect, BestIndex, Disconnect, Disconnect, Open,
+      Close,   Filter,  Next,    Eof,       Column,     RowId,      nullptr,
+      nullptr, nullptr, nullptr, nullptr,   nullptr,    nullptr};
+
+  return sqlite3_create_module(aDB, aName, &module, nullptr);
+}
+
+}  // namespace storage
+}  // namespace mozilla
diff --git a/storage/FileSystemModule.h b/storage/FileSystemModule.h
new file mode 100644
index 0000000000..28731a1bdb
--- /dev/null
+++ b/storage/FileSystemModule.h
@@ -0,0 +1,22 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_storage_FileSystemModule_h
+#define mozilla_storage_FileSystemModule_h
+
+#include "nscore.h"
+
+struct sqlite3;
+
+namespace mozilla {
+namespace storage {
+
+int RegisterFileSystemModule(sqlite3* aDB, const char* aName);
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif  // mozilla_storage_FileSystemModule_h
diff --git a/storage/IStorageBindingParamsInternal.h b/storage/IStorageBindingParamsInternal.h
new file mode 100644
index 0000000000..a056ae3269
--- /dev/null
+++ b/storage/IStorageBindingParamsInternal.h
@@ -0,0 +1,54 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 sts=2 expandtab
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_storage_IStorageBindingParamsInternal_h_
+#define mozilla_storage_IStorageBindingParamsInternal_h_
+
+#include "nsISupports.h"
+
+struct sqlite3_stmt;
+class mozIStorageError;
+
+namespace mozilla {
+namespace storage {
+
+#define ISTORAGEBINDINGPARAMSINTERNAL_IID            \
+  {                                                  \
+    0x4c43d33a, 0xc620, 0x41b8, {                    \
+      0xba, 0x1d, 0x50, 0xc5, 0xb1, 0xe9, 0x1a, 0x04 \
+    }                                                \
+  }
+
+/**
+ * Implementation-only interface for mozIStorageBindingParams.  This defines the
+ * set of methods required by the asynchronous execution code in order to
+ * consume the contents stored in mozIStorageBindingParams instances.
+ */
+class IStorageBindingParamsInternal : public nsISupports {
+ public:
+  NS_DECLARE_STATIC_IID_ACCESSOR(ISTORAGEBINDINGPARAMSINTERNAL_IID)
+
+  /**
+   * Binds our stored data to the statement.
+   *
+   * @param aStatement
+   *        The statement to bind our data to.
+   * @return nullptr on success, or a mozIStorageError object if an error
+   *         occurred.
+   */
+  virtual already_AddRefed<mozIStorageError> bind(sqlite3_stmt* aStatement) = 0;
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(IStorageBindingParamsInternal,
+                              ISTORAGEBINDINGPARAMSINTERNAL_IID)
+
+#define NS_DECL_ISTORAGEBINDINGPARAMSINTERNAL \
+  already_AddRefed<mozIStorageError> bind(sqlite3_stmt* aStatement) override;
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif  // mozilla_storage_IStorageBindingParamsInternal_h_
diff --git a/storage/ObfuscatingVFS.cpp b/storage/ObfuscatingVFS.cpp
new file mode 100644
index 0000000000..107384376c
--- /dev/null
+++ b/storage/ObfuscatingVFS.cpp
@@ -0,0 +1,696 @@
+/*
+** 2020-04-20
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file implements a VFS shim that obfuscates database content
+** written to disk by applying a CipherStrategy.
+**
+** COMPILING
+**
+** This extension requires SQLite 3.32.0 or later.
+**
+**
+** LOADING
+**
+** Initialize it using a single API call as follows:
+**
+**     sqlite3_obfsvfs_init();
+**
+** Obfsvfs is a VFS Shim. When loaded, "obfsvfs" becomes the new
+** default VFS and it uses the prior default VFS as the next VFS
+** down in the stack.  This is normally what you want.  However, it
+** complex situations where multiple VFS shims are being loaded,
+** it might be important to ensure that obfsvfs is loaded in the
+** correct order so that it sequences itself into the default VFS
+** Shim stack in the right order.
+**
+** USING
+**
+** Open database connections using the sqlite3_open_v2() with
+** the SQLITE_OPEN_URI flag and using a URI filename that includes
+** the query parameter "key=XXXXXXXXXXX..." where the XXXX... consists
+** of 64 hexadecimal digits (32 bytes of content).
+**
+** Create a new encrypted database by opening a file that does not
+** yet exist using the key= query parameter.
+**
+** LIMITATIONS:
+**
+**    *   An obfuscated database must be created as such.  There is
+**        no way to convert an existing database file into an
+**        obfuscated database file other than to run ".dump" on the
+**        older database and reimport the SQL text into a new
+**        obfuscated database.
+**
+**    *   There is no way to change the key value, other than to
+**        ".dump" and restore the database
+**
+**    *   The database page size must be exactly 8192 bytes.  No other
+**        database page sizes are currently supported.
+**
+**    *   Memory-mapped I/O does not work for obfuscated databases.
+**        If you think about it, memory-mapped I/O doesn't make any
+**        sense for obfuscated databases since you have to make a
+**        copy of the content to deobfuscate anyhow - you might as
+**        well use normal read()/write().
+**
+**    *   Only the main database, the rollback journal, and WAL file
+**        are obfuscated.  Other temporary files used for things like
+**        SAVEPOINTs or as part of a large external sort remain
+**        unobfuscated.
+**
+**    *   Requires SQLite 3.32.0 or later.
+*/
+#include "ObfuscatingVFS.h"
+
+#include <string.h>
+#include <ctype.h>
+#include <stdio.h> /* For debugging only */
+
+#include "mozilla/dom/quota/IPCStreamCipherStrategy.h"
+#include "mozilla/ScopeExit.h"
+#include "nsPrintfCString.h"
+#include "QuotaVFS.h"
+#include "sqlite3.h"
+
+/*
+** Forward declaration of objects used by this utility
+*/
+using ObfsVfs = sqlite3_vfs;
+
+/*
+** Useful datatype abbreviations
+*/
+#if !defined(SQLITE_CORE)
+using u8 = unsigned char;
+#endif
+
+/* Access to a lower-level VFS that (might) implement dynamic loading,
+** access to randomness, etc.
+*/
+#define ORIGVFS(p) ((sqlite3_vfs*)((p)->pAppData))
+#define ORIGFILE(p) ((sqlite3_file*)(((ObfsFile*)(p)) + 1))
+
+/*
+** Database page size for obfuscated databases
+*/
+#define OBFS_PGSZ 8192
+
+#define WAL_FRAMEHDRSIZE 24
+
+using namespace mozilla;
+using namespace mozilla::dom::quota;
+
+/* An open file */
+struct ObfsFile {
+  sqlite3_file base;  /* IO methods */
+  const char* zFName; /* Original name of the file */
+  bool inCkpt;        /* Currently doing a checkpoint */
+  ObfsFile* pPartner; /* Ptr from WAL to main-db, or from main-db to WAL */
+  void* pTemp;        /* Temporary storage for encoded pages */
+  IPCStreamCipherStrategy*
+      encryptCipherStrategy; /* CipherStrategy for encryption */
+  IPCStreamCipherStrategy*
+      decryptCipherStrategy; /* CipherStrategy for decryption */
+};
+
+/*
+** Methods for ObfsFile
+*/
+static int obfsClose(sqlite3_file*);
+static int obfsRead(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
+static int obfsWrite(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
+static int obfsTruncate(sqlite3_file*, sqlite3_int64 size);
+static int obfsSync(sqlite3_file*, int flags);
+static int obfsFileSize(sqlite3_file*, sqlite3_int64* pSize);
+static int obfsLock(sqlite3_file*, int);
+static int obfsUnlock(sqlite3_file*, int);
+static int obfsCheckReservedLock(sqlite3_file*, int* pResOut);
+static int obfsFileControl(sqlite3_file*, int op, void* pArg);
+static int obfsSectorSize(sqlite3_file*);
+static int obfsDeviceCharacteristics(sqlite3_file*);
+static int obfsShmMap(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
+static int obfsShmLock(sqlite3_file*, int offset, int n, int flags);
+static void obfsShmBarrier(sqlite3_file*);
+static int obfsShmUnmap(sqlite3_file*, int deleteFlag);
+static int obfsFetch(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void** pp);
+static int obfsUnfetch(sqlite3_file*, sqlite3_int64 iOfst, void* p);
+
+/*
+** Methods for ObfsVfs
+*/
+static int obfsOpen(sqlite3_vfs*, const char*, sqlite3_file*, int, int*);
+static int obfsDelete(sqlite3_vfs*, const char* zPath, int syncDir);
+static int obfsAccess(sqlite3_vfs*, const char* zPath, int flags, int*);
+static int obfsFullPathname(sqlite3_vfs*, const char* zPath, int, char* zOut);
+static void* obfsDlOpen(sqlite3_vfs*, const char* zPath);
+static void obfsDlError(sqlite3_vfs*, int nByte, char* zErrMsg);
+static void (*obfsDlSym(sqlite3_vfs* pVfs, void* p, const char* zSym))(void);
+static void obfsDlClose(sqlite3_vfs*, void*);
+static int obfsRandomness(sqlite3_vfs*, int nByte, char* zBufOut);
+static int obfsSleep(sqlite3_vfs*, int nMicroseconds);
+static int obfsCurrentTime(sqlite3_vfs*, double*);
+static int obfsGetLastError(sqlite3_vfs*, int, char*);
+static int obfsCurrentTimeInt64(sqlite3_vfs*, sqlite3_int64*);
+static int obfsSetSystemCall(sqlite3_vfs*, const char*, sqlite3_syscall_ptr);
+static sqlite3_syscall_ptr obfsGetSystemCall(sqlite3_vfs*, const char* z);
+static const char* obfsNextSystemCall(sqlite3_vfs*, const char* zName);
+
+static const sqlite3_io_methods obfs_io_methods = {
+    3,                         /* iVersion */
+    obfsClose,                 /* xClose */
+    obfsRead,                  /* xRead */
+    obfsWrite,                 /* xWrite */
+    obfsTruncate,              /* xTruncate */
+    obfsSync,                  /* xSync */
+    obfsFileSize,              /* xFileSize */
+    obfsLock,                  /* xLock */
+    obfsUnlock,                /* xUnlock */
+    obfsCheckReservedLock,     /* xCheckReservedLock */
+    obfsFileControl,           /* xFileControl */
+    obfsSectorSize,            /* xSectorSize */
+    obfsDeviceCharacteristics, /* xDeviceCharacteristics */
+    obfsShmMap,                /* xShmMap */
+    obfsShmLock,               /* xShmLock */
+    obfsShmBarrier,            /* xShmBarrier */
+    obfsShmUnmap,              /* xShmUnmap */
+    obfsFetch,                 /* xFetch */
+    obfsUnfetch                /* xUnfetch */
+};
+
+static constexpr int kKeyBytes = 32;
+static constexpr int kIvBytes = IPCStreamCipherStrategy::BlockPrefixLength;
+static constexpr int kClearTextPrefixBytesOnFirstPage = 32;
+static constexpr int kReservedBytes = 32;
+static constexpr int kBasicBlockSize = IPCStreamCipherStrategy::BasicBlockSize;
+static_assert(kClearTextPrefixBytesOnFirstPage % kBasicBlockSize == 0);
+static_assert(kReservedBytes % kBasicBlockSize == 0);
+
+/* Obfuscate a page using p->encryptCipherStrategy.
+**
+** A new random nonce is created and stored in the last 32 bytes
+** of the page.  All other bytes of the page are obfuscasted using the
+** CipherStrategy.  Except, for page-1 (including the SQLite
+** database header) the first 32 bytes are not obfuscated
+**
+** Return a pointer to the obfuscated content, which is held in the
+** p->pTemp buffer.  Or return a NULL pointer if something goes wrong.
+** Errors are reported using NS_WARNING().
+*/
+static void* obfsEncode(ObfsFile* p, /* File containing page to be obfuscated */
+                        u8* a,       /* database page to be obfuscated */
+                        int nByte /* Bytes of content in a[]. Must be a multiple
+                                     of kBasicBlockSize. */
+) {
+  u8 aIv[kIvBytes];
+  u8* pOut;
+  int i;
+
+  static_assert((kIvBytes & (kIvBytes - 1)) == 0);
+  sqlite3_randomness(kIvBytes, aIv);
+  pOut = (u8*)p->pTemp;
+  if (pOut == nullptr) {
+    pOut = static_cast<u8*>(sqlite3_malloc64(nByte));
+    if (pOut == nullptr) {
+      NS_WARNING(nsPrintfCString("unable to allocate a buffer in which to"
+                                 " write obfuscated database content for %s",
+                                 p->zFName)
+                     .get());
+      return nullptr;
+    }
+    p->pTemp = pOut;
+  }
+  if (memcmp(a, "SQLite format 3", 16) == 0) {
+    i = kClearTextPrefixBytesOnFirstPage;
+    if (a[20] != kReservedBytes) {
+      NS_WARNING(nsPrintfCString("obfuscated database must have reserved-bytes"
+                                 " set to %d",
+                                 kReservedBytes)
+                     .get());
+      return nullptr;
+    }
+    memcpy(pOut, a, kClearTextPrefixBytesOnFirstPage);
+  } else {
+    i = 0;
+  }
+  const int payloadLength = nByte - kReservedBytes - i;
+  MOZ_ASSERT(payloadLength > 0);
+  // XXX I guess this can be done in-place as well, then we don't need the
+  // temporary page at all, I guess?
+  p->encryptCipherStrategy->Cipher(
+      Span{aIv}, Span{a + i, static_cast<unsigned>(payloadLength)},
+      Span{pOut + i, static_cast<unsigned>(payloadLength)});
+  memcpy(pOut + nByte - kReservedBytes, aIv, kIvBytes);
+
+  return pOut;
+}
+
+/* De-obfuscate a page using p->decryptCipherStrategy.
+**
+** The deobfuscation is done in-place.
+**
+** For pages that begin with the SQLite header text, the first
+** 32 bytes are not deobfuscated.
+*/
+static void obfsDecode(ObfsFile* p, /* File containing page to be obfuscated */
+                       u8* a,       /* database page to be obfuscated */
+                       int nByte /* Bytes of content in a[]. Must be a multiple
+                                    of kBasicBlockSize. */
+) {
+  int i;
+
+  if (memcmp(a, "SQLite format 3", 16) == 0) {
+    i = kClearTextPrefixBytesOnFirstPage;
+  } else {
+    i = 0;
+  }
+  const int payloadLength = nByte - kReservedBytes - i;
+  MOZ_ASSERT(payloadLength > 0);
+  p->decryptCipherStrategy->Cipher(
+      Span{a + nByte - kReservedBytes, kIvBytes},
+      Span{a + i, static_cast<unsigned>(payloadLength)},
+      Span{a + i, static_cast<unsigned>(payloadLength)});
+  memset(a + nByte - kReservedBytes, 0, kIvBytes);
+}
+
+/*
+** Close an obfsucated file.
+*/
+static int obfsClose(sqlite3_file* pFile) {
+  ObfsFile* p = (ObfsFile*)pFile;
+  if (p->pPartner) {
+    MOZ_ASSERT(p->pPartner->pPartner == p);
+    p->pPartner->pPartner = nullptr;
+    p->pPartner = nullptr;
+  }
+  sqlite3_free(p->pTemp);
+
+  delete p->decryptCipherStrategy;
+  delete p->encryptCipherStrategy;
+
+  pFile = ORIGFILE(pFile);
+  return pFile->pMethods->xClose(pFile);
+}
+
+/*
+** Read data from an obfuscated file.
+**
+** If the file is less than one full page in length, then return
+** a substitute "prototype" page-1.  This prototype page one
+** specifies a database in WAL mode with an 8192-byte page size
+** and a 32-byte reserved-bytes value.  Those settings are necessary
+** for obfuscation to function correctly.
+*/
+static int obfsRead(sqlite3_file* pFile, void* zBuf, int iAmt,
+                    sqlite_int64 iOfst) {
+  int rc;
+  ObfsFile* p = (ObfsFile*)pFile;
+  pFile = ORIGFILE(pFile);
+  rc = pFile->pMethods->xRead(pFile, zBuf, iAmt, iOfst);
+  if (rc == SQLITE_OK) {
+    if ((iAmt == OBFS_PGSZ || iAmt == OBFS_PGSZ + WAL_FRAMEHDRSIZE) &&
+        !p->inCkpt) {
+      obfsDecode(p, ((u8*)zBuf) + iAmt - OBFS_PGSZ, OBFS_PGSZ);
+    }
+  } else if (rc == SQLITE_IOERR_SHORT_READ && iOfst == 0 && iAmt >= 100) {
+    static const unsigned char aEmptyDb[] = {
+        // Offset 0, Size 16, The header string: "SQLite format 3\000"
+        0x53, 0x51, 0x4c, 0x69, 0x74, 0x65, 0x20, 0x66, 0x6f, 0x72, 0x6d, 0x61,
+        0x74, 0x20, 0x33, 0x00,
+        // XXX Add description for other fields
+        0x20, 0x00, 0x02, 0x02, kReservedBytes, 0x40, 0x20, 0x20, 0x00, 0x00,
+        0x00, 0x01, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00,
+        // Offset 52, Size 4, The page number of the largest root b-tree page
+        // when in auto-vacuum or incremental-vacuum modes, or zero otherwise.
+        0x00, 0x00, 0x00, 0x01};
+
+    memcpy(zBuf, aEmptyDb, sizeof(aEmptyDb));
+    memset(((u8*)zBuf) + sizeof(aEmptyDb), 0, iAmt - sizeof(aEmptyDb));
+    rc = SQLITE_OK;
+  }
+  return rc;
+}
+
+/*
+** Write data to an obfuscated file or journal.
+*/
+static int obfsWrite(sqlite3_file* pFile, const void* zBuf, int iAmt,
+                     sqlite_int64 iOfst) {
+  ObfsFile* p = (ObfsFile*)pFile;
+  pFile = ORIGFILE(pFile);
+  if (iAmt == OBFS_PGSZ && !p->inCkpt) {
+    zBuf = obfsEncode(p, (u8*)zBuf, iAmt);
+    if (zBuf == nullptr) {
+      return SQLITE_IOERR;
+    }
+  }
+  return pFile->pMethods->xWrite(pFile, zBuf, iAmt, iOfst);
+}
+
+/*
+** Truncate an obfuscated file.
+*/
+static int obfsTruncate(sqlite3_file* pFile, sqlite_int64 size) {
+  pFile = ORIGFILE(pFile);
+  return pFile->pMethods->xTruncate(pFile, size);
+}
+
+/*
+** Sync an obfuscated file.
+*/
+static int obfsSync(sqlite3_file* pFile, int flags) {
+  pFile = ORIGFILE(pFile);
+  return pFile->pMethods->xSync(pFile, flags);
+}
+
+/*
+** Return the current file-size of an obfuscated file.
+*/
+static int obfsFileSize(sqlite3_file* pFile, sqlite_int64* pSize) {
+  ObfsFile* p = (ObfsFile*)pFile;
+  pFile = ORIGFILE(p);
+  return pFile->pMethods->xFileSize(pFile, pSize);
+}
+
+/*
+** Lock an obfuscated file.
+*/
+static int obfsLock(sqlite3_file* pFile, int eLock) {
+  pFile = ORIGFILE(pFile);
+  return pFile->pMethods->xLock(pFile, eLock);
+}
+
+/*
+** Unlock an obfuscated file.
+*/
+static int obfsUnlock(sqlite3_file* pFile, int eLock) {
+  pFile = ORIGFILE(pFile);
+  return pFile->pMethods->xUnlock(pFile, eLock);
+}
+
+/*
+** Check if another file-handle holds a RESERVED lock on an obfuscated file.
+*/
+static int obfsCheckReservedLock(sqlite3_file* pFile, int* pResOut) {
+  pFile = ORIGFILE(pFile);
+  return pFile->pMethods->xCheckReservedLock(pFile, pResOut);
+}
+
+/*
+** File control method. For custom operations on an obfuscated file.
+*/
+static int obfsFileControl(sqlite3_file* pFile, int op, void* pArg) {
+  int rc;
+  ObfsFile* p = (ObfsFile*)pFile;
+  pFile = ORIGFILE(pFile);
+  if (op == SQLITE_FCNTL_PRAGMA) {
+    char** azArg = (char**)pArg;
+    MOZ_ASSERT(azArg[1] != nullptr);
+    if (azArg[2] != nullptr && sqlite3_stricmp(azArg[1], "page_size") == 0) {
+      /* Do not allow page size changes on an obfuscated database */
+      return SQLITE_OK;
+    }
+  } else if (op == SQLITE_FCNTL_CKPT_START || op == SQLITE_FCNTL_CKPT_DONE) {
+    p->inCkpt = op == SQLITE_FCNTL_CKPT_START;
+    if (p->pPartner) {
+      p->pPartner->inCkpt = p->inCkpt;
+    }
+  }
+  rc = pFile->pMethods->xFileControl(pFile, op, pArg);
+  if (rc == SQLITE_OK && op == SQLITE_FCNTL_VFSNAME) {
+    *(char**)pArg = sqlite3_mprintf("obfs/%z", *(char**)pArg);
+  }
+  return rc;
+}
+
+/*
+** Return the sector-size in bytes for an obfuscated file.
+*/
+static int obfsSectorSize(sqlite3_file* pFile) {
+  pFile = ORIGFILE(pFile);
+  return pFile->pMethods->xSectorSize(pFile);
+}
+
+/*
+** Return the device characteristic flags supported by an obfuscated file.
+*/
+static int obfsDeviceCharacteristics(sqlite3_file* pFile) {
+  pFile = ORIGFILE(pFile);
+  return pFile->pMethods->xDeviceCharacteristics(pFile);
+}
+
+/* Create a shared memory file mapping */
+static int obfsShmMap(sqlite3_file* pFile, int iPg, int pgsz, int bExtend,
+                      void volatile** pp) {
+  pFile = ORIGFILE(pFile);
+  return pFile->pMethods->xShmMap(pFile, iPg, pgsz, bExtend, pp);
+}
+
+/* Perform locking on a shared-memory segment */
+static int obfsShmLock(sqlite3_file* pFile, int offset, int n, int flags) {
+  pFile = ORIGFILE(pFile);
+  return pFile->pMethods->xShmLock(pFile, offset, n, flags);
+}
+
+/* Memory barrier operation on shared memory */
+static void obfsShmBarrier(sqlite3_file* pFile) {
+  pFile = ORIGFILE(pFile);
+  pFile->pMethods->xShmBarrier(pFile);
+}
+
+/* Unmap a shared memory segment */
+static int obfsShmUnmap(sqlite3_file* pFile, int deleteFlag) {
+  pFile = ORIGFILE(pFile);
+  return pFile->pMethods->xShmUnmap(pFile, deleteFlag);
+}
+
+/* Fetch a page of a memory-mapped file */
+static int obfsFetch(sqlite3_file* pFile, sqlite3_int64 iOfst, int iAmt,
+                     void** pp) {
+  *pp = nullptr;
+  return SQLITE_OK;
+}
+
+/* Release a memory-mapped page */
+static int obfsUnfetch(sqlite3_file* pFile, sqlite3_int64 iOfst, void* pPage) {
+  pFile = ORIGFILE(pFile);
+  return pFile->pMethods->xUnfetch(pFile, iOfst, pPage);
+}
+
+/*
+** Translate a single byte of Hex into an integer.
+** This routine only works if h really is a valid hexadecimal
+** character:  0..9a..fA..F
+*/
+static u8 obfsHexToInt(int h) {
+  MOZ_ASSERT((h >= '0' && h <= '9') || (h >= 'a' && h <= 'f') ||
+             (h >= 'A' && h <= 'F'));
+#if 1 /* ASCII */
+  h += 9 * (1 & (h >> 6));
+#else /* EBCDIC */
+  h += 9 * (1 & ~(h >> 4));
+#endif
+  return (u8)(h & 0xf);
+}
+
+/*
+** Open a new file.
+**
+** If the file is an ordinary database file, or a rollback or WAL journal
+** file, and if the key=XXXX parameter exists, then try to open the file
+** as an obfuscated database.  All other open attempts fall through into
+** the lower-level VFS shim.
+**
+** If the key=XXXX parameter exists but is not 64-bytes of hex key, then
+** put an error message in NS_WARNING() and return SQLITE_CANTOPEN.
+*/
+static int obfsOpen(sqlite3_vfs* pVfs, const char* zName, sqlite3_file* pFile,
+                    int flags, int* pOutFlags) {
+  ObfsFile* p;
+  sqlite3_file* pSubFile;
+  sqlite3_vfs* pSubVfs;
+  int rc, i;
+  const char* zKey;
+  u8 aKey[kKeyBytes];
+  pSubVfs = ORIGVFS(pVfs);
+  if (flags &
+      (SQLITE_OPEN_MAIN_DB | SQLITE_OPEN_WAL | SQLITE_OPEN_MAIN_JOURNAL)) {
+    zKey = sqlite3_uri_parameter(zName, "key");
+  } else {
+    zKey = nullptr;
+  }
+  if (zKey == nullptr) {
+    return pSubVfs->xOpen(pSubVfs, zName, pFile, flags, pOutFlags);
+  }
+  for (i = 0;
+       i < kKeyBytes && isxdigit(zKey[i * 2]) && isxdigit(zKey[i * 2 + 1]);
+       i++) {
+    aKey[i] = (obfsHexToInt(zKey[i * 2]) << 4) | obfsHexToInt(zKey[i * 2 + 1]);
+  }
+  if (i != kKeyBytes) {
+    NS_WARNING(
+        nsPrintfCString("invalid query parameter on %s: key=%s", zName, zKey)
+            .get());
+    return SQLITE_CANTOPEN;
+  }
+  p = (ObfsFile*)pFile;
+  memset(p, 0, sizeof(*p));
+
+  auto encryptCipherStrategy = MakeUnique<IPCStreamCipherStrategy>();
+  auto decryptCipherStrategy = MakeUnique<IPCStreamCipherStrategy>();
+
+  auto resetMethods = MakeScopeExit([pFile] { pFile->pMethods = nullptr; });
+
+  if (NS_WARN_IF(NS_FAILED(encryptCipherStrategy->Init(
+          CipherMode::Encrypt, Span{aKey, sizeof(aKey)},
+          IPCStreamCipherStrategy::MakeBlockPrefix())))) {
+    return SQLITE_ERROR;
+  }
+
+  if (NS_WARN_IF(NS_FAILED(decryptCipherStrategy->Init(
+          CipherMode::Decrypt, Span{aKey, sizeof(aKey)})))) {
+    return SQLITE_ERROR;
+  }
+
+  pSubFile = ORIGFILE(pFile);
+  p->base.pMethods = &obfs_io_methods;
+  rc = pSubVfs->xOpen(pSubVfs, zName, pSubFile, flags, pOutFlags);
+  if (rc) {
+    return rc;
+  }
+
+  resetMethods.release();
+
+  if (flags & (SQLITE_OPEN_WAL | SQLITE_OPEN_MAIN_JOURNAL)) {
+    sqlite3_file* pDb = sqlite3_database_file_object(zName);
+    p->pPartner = (ObfsFile*)pDb;
+    MOZ_ASSERT(p->pPartner->pPartner == nullptr);
+    p->pPartner->pPartner = p;
+  }
+  p->zFName = zName;
+
+  p->encryptCipherStrategy = encryptCipherStrategy.release();
+  p->decryptCipherStrategy = decryptCipherStrategy.release();
+
+  return SQLITE_OK;
+}
+
+/*
+** All other VFS methods are pass-thrus.
+*/
+static int obfsDelete(sqlite3_vfs* pVfs, const char* zPath, int syncDir) {
+  return ORIGVFS(pVfs)->xDelete(ORIGVFS(pVfs), zPath, syncDir);
+}
+static int obfsAccess(sqlite3_vfs* pVfs, const char* zPath, int flags,
+                      int* pResOut) {
+  return ORIGVFS(pVfs)->xAccess(ORIGVFS(pVfs), zPath, flags, pResOut);
+}
+static int obfsFullPathname(sqlite3_vfs* pVfs, const char* zPath, int nOut,
+                            char* zOut) {
+  return ORIGVFS(pVfs)->xFullPathname(ORIGVFS(pVfs), zPath, nOut, zOut);
+}
+static void* obfsDlOpen(sqlite3_vfs* pVfs, const char* zPath) {
+  return ORIGVFS(pVfs)->xDlOpen(ORIGVFS(pVfs), zPath);
+}
+static void obfsDlError(sqlite3_vfs* pVfs, int nByte, char* zErrMsg) {
+  ORIGVFS(pVfs)->xDlError(ORIGVFS(pVfs), nByte, zErrMsg);
+}
+static void (*obfsDlSym(sqlite3_vfs* pVfs, void* p, const char* zSym))(void) {
+  return ORIGVFS(pVfs)->xDlSym(ORIGVFS(pVfs), p, zSym);
+}
+static void obfsDlClose(sqlite3_vfs* pVfs, void* pHandle) {
+  ORIGVFS(pVfs)->xDlClose(ORIGVFS(pVfs), pHandle);
+}
+static int obfsRandomness(sqlite3_vfs* pVfs, int nByte, char* zBufOut) {
+  return ORIGVFS(pVfs)->xRandomness(ORIGVFS(pVfs), nByte, zBufOut);
+}
+static int obfsSleep(sqlite3_vfs* pVfs, int nMicroseconds) {
+  return ORIGVFS(pVfs)->xSleep(ORIGVFS(pVfs), nMicroseconds);
+}
+static int obfsCurrentTime(sqlite3_vfs* pVfs, double* pTimeOut) {
+  return ORIGVFS(pVfs)->xCurrentTime(ORIGVFS(pVfs), pTimeOut);
+}
+static int obfsGetLastError(sqlite3_vfs* pVfs, int a, char* b) {
+  return ORIGVFS(pVfs)->xGetLastError(ORIGVFS(pVfs), a, b);
+}
+static int obfsCurrentTimeInt64(sqlite3_vfs* pVfs, sqlite3_int64* p) {
+  return ORIGVFS(pVfs)->xCurrentTimeInt64(ORIGVFS(pVfs), p);
+}
+static int obfsSetSystemCall(sqlite3_vfs* pVfs, const char* zName,
+                             sqlite3_syscall_ptr pCall) {
+  return ORIGVFS(pVfs)->xSetSystemCall(ORIGVFS(pVfs), zName, pCall);
+}
+static sqlite3_syscall_ptr obfsGetSystemCall(sqlite3_vfs* pVfs,
+                                             const char* zName) {
+  return ORIGVFS(pVfs)->xGetSystemCall(ORIGVFS(pVfs), zName);
+}
+static const char* obfsNextSystemCall(sqlite3_vfs* pVfs, const char* zName) {
+  return ORIGVFS(pVfs)->xNextSystemCall(ORIGVFS(pVfs), zName);
+}
+
+namespace mozilla::storage::obfsvfs {
+
+const char* GetVFSName() { return "obfsvfs"; }
+
+UniquePtr<sqlite3_vfs> ConstructVFS(const char* aBaseVFSName) {
+  MOZ_ASSERT(aBaseVFSName);
+
+  if (sqlite3_vfs_find(GetVFSName()) != nullptr) {
+    return nullptr;
+  }
+  sqlite3_vfs* const pOrig = sqlite3_vfs_find(aBaseVFSName);
+  if (pOrig == nullptr) {
+    return nullptr;
+  }
+
+#ifdef DEBUG
+  // If the VFS version is higher than the last known one, you should update
+  // this VFS adding appropriate methods for any methods added in the version
+  // change.
+  static constexpr int kLastKnownVfsVersion = 3;
+  MOZ_ASSERT(pOrig->iVersion <= kLastKnownVfsVersion);
+#endif
+
+  const sqlite3_vfs obfs_vfs = {
+      pOrig->iVersion,                                      /* iVersion  */
+      static_cast<int>(pOrig->szOsFile + sizeof(ObfsFile)), /* szOsFile */
+      pOrig->mxPathname,                                    /* mxPathname */
+      nullptr,                                              /* pNext */
+      GetVFSName(),                                         /* zName */
+      pOrig,                                                /* pAppData */
+      obfsOpen,                                             /* xOpen */
+      obfsDelete,                                           /* xDelete */
+      obfsAccess,                                           /* xAccess */
+      obfsFullPathname,                                     /* xFullPathname */
+      obfsDlOpen,                                           /* xDlOpen */
+      obfsDlError,                                          /* xDlError */
+      obfsDlSym,                                            /* xDlSym */
+      obfsDlClose,                                          /* xDlClose */
+      obfsRandomness,                                       /* xRandomness */
+      obfsSleep,                                            /* xSleep */
+      obfsCurrentTime,                                      /* xCurrentTime */
+      obfsGetLastError,                                     /* xGetLastError */
+      obfsCurrentTimeInt64, /* xCurrentTimeInt64 */
+      obfsSetSystemCall,    /* xSetSystemCall */
+      obfsGetSystemCall,    /* xGetSystemCall */
+      obfsNextSystemCall    /* xNextSystemCall */
+  };
+
+  return MakeUnique<sqlite3_vfs>(obfs_vfs);
+}
+
+already_AddRefed<QuotaObject> GetQuotaObjectForFile(sqlite3_file* pFile) {
+  return quotavfs::GetQuotaObjectForFile(ORIGFILE(pFile));
+}
+
+}  // namespace mozilla::storage::obfsvfs
diff --git a/storage/ObfuscatingVFS.h b/storage/ObfuscatingVFS.h
new file mode 100644
index 0000000000..24d0e40a40
--- /dev/null
+++ b/storage/ObfuscatingVFS.h
@@ -0,0 +1,33 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef STORAGE_OBFUSCATINGVFS_H_
+#define STORAGE_OBFUSCATINGVFS_H_
+
+#include "mozilla/UniquePtr.h"
+
+struct sqlite3_vfs;
+struct sqlite3_file;
+
+template <typename T>
+struct already_AddRefed;
+
+namespace mozilla::dom::quota {
+class QuotaObject;
+}
+
+namespace mozilla::storage::obfsvfs {
+
+const char* GetVFSName();
+
+UniquePtr<sqlite3_vfs> ConstructVFS(const char* aBaseVFSName);
+
+already_AddRefed<dom::quota::QuotaObject> GetQuotaObjectForFile(
+    sqlite3_file* pFile);
+
+}  // namespace mozilla::storage::obfsvfs
+
+#endif  // STORAGE_OBFUSCATINGVFS_H_
diff --git a/storage/QuotaVFS.cpp b/storage/QuotaVFS.cpp
new file mode 100644
index 0000000000..b9490ff0d5
--- /dev/null
+++ b/storage/QuotaVFS.cpp
@@ -0,0 +1,621 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "QuotaVFS.h"
+
+#include "mozilla/dom/quota/PersistenceType.h"
+#include "mozilla/dom/quota/QuotaManager.h"
+#include "mozilla/dom/quota/QuotaObject.h"
+#include "mozilla/dom/quota/ResultExtensions.h"
+#include "mozilla/StaticPrefs_storage.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsEscape.h"
+#include "sqlite3.h"
+
+#if defined(XP_WIN) || defined(XP_UNIX)
+#  include "mozilla/StaticPrefs_dom.h"
+#endif
+
+// The last VFS version for which this file has been updated.
+#define LAST_KNOWN_VFS_VERSION 3
+
+// The last io_methods version for which this file has been updated.
+#define LAST_KNOWN_IOMETHODS_VERSION 3
+
+namespace {
+
+using namespace mozilla;
+using namespace mozilla::dom::quota;
+
+struct QuotaFile {
+  // Base class.  Must be first
+  sqlite3_file base;
+
+  // quota object for this file
+  RefPtr<QuotaObject> quotaObject;
+
+  // The chunk size for this file. See the documentation for
+  // sqlite3_file_control() and FCNTL_CHUNK_SIZE.
+  int fileChunkSize;
+
+  // This contains the vfs that actually does work
+  sqlite3_file pReal[1];
+};
+
+already_AddRefed<QuotaObject> GetQuotaObjectFromName(const char* zName) {
+  MOZ_ASSERT(zName);
+
+  const char* directoryLockIdParam =
+      sqlite3_uri_parameter(zName, "directoryLockId");
+  if (!directoryLockIdParam) {
+    return nullptr;
+  }
+
+  nsresult rv;
+  const int64_t directoryLockId =
+      nsDependentCString(directoryLockIdParam).ToInteger64(&rv);
+  MOZ_RELEASE_ASSERT(NS_SUCCEEDED(rv));
+
+  QuotaManager* quotaManager = QuotaManager::Get();
+  MOZ_ASSERT(quotaManager);
+
+  return quotaManager->GetQuotaObject(directoryLockId,
+                                      NS_ConvertUTF8toUTF16(zName));
+}
+
+void MaybeEstablishQuotaControl(const char* zName, QuotaFile* pFile,
+                                int flags) {
+  MOZ_ASSERT(pFile);
+  MOZ_ASSERT(!pFile->quotaObject);
+
+  if (!(flags & (SQLITE_OPEN_URI | SQLITE_OPEN_WAL))) {
+    return;
+  }
+  pFile->quotaObject = GetQuotaObjectFromName(zName);
+}
+
+/*
+** Close a QuotaFile.
+*/
+int QuotaClose(sqlite3_file* pFile) {
+  QuotaFile* p = (QuotaFile*)pFile;
+  int rc;
+  rc = p->pReal->pMethods->xClose(p->pReal);
+  if (rc == SQLITE_OK) {
+    delete p->base.pMethods;
+    p->base.pMethods = nullptr;
+    p->quotaObject = nullptr;
+#ifdef DEBUG
+    p->fileChunkSize = 0;
+#endif
+  }
+  return rc;
+}
+
+/*
+** Read data from a QuotaFile.
+*/
+int QuotaRead(sqlite3_file* pFile, void* zBuf, int iAmt, sqlite_int64 iOfst) {
+  QuotaFile* p = (QuotaFile*)pFile;
+  int rc;
+  rc = p->pReal->pMethods->xRead(p->pReal, zBuf, iAmt, iOfst);
+  return rc;
+}
+
+/*
+** Return the current file-size of a QuotaFile.
+*/
+int QuotaFileSize(sqlite3_file* pFile, sqlite_int64* pSize) {
+  QuotaFile* p = (QuotaFile*)pFile;
+  int rc;
+  rc = p->pReal->pMethods->xFileSize(p->pReal, pSize);
+  return rc;
+}
+
+/*
+** Write data to a QuotaFile.
+*/
+int QuotaWrite(sqlite3_file* pFile, const void* zBuf, int iAmt,
+               sqlite_int64 iOfst) {
+  QuotaFile* p = (QuotaFile*)pFile;
+  int rc;
+  if (p->quotaObject) {
+    MOZ_ASSERT(INT64_MAX - iOfst >= iAmt);
+    if (!p->quotaObject->MaybeUpdateSize(iOfst + iAmt, /* aTruncate */ false)) {
+      return SQLITE_FULL;
+    }
+  }
+  rc = p->pReal->pMethods->xWrite(p->pReal, zBuf, iAmt, iOfst);
+  if (p->quotaObject && rc != SQLITE_OK) {
+    NS_WARNING(
+        "xWrite failed on a quota-controlled file, attempting to "
+        "update its current size...");
+    sqlite_int64 currentSize;
+    if (QuotaFileSize(pFile, &currentSize) == SQLITE_OK) {
+      DebugOnly<bool> res =
+          p->quotaObject->MaybeUpdateSize(currentSize, /* aTruncate */ true);
+      MOZ_ASSERT(res);
+    }
+  }
+  return rc;
+}
+
+/*
+** Truncate a QuotaFile.
+*/
+int QuotaTruncate(sqlite3_file* pFile, sqlite_int64 size) {
+  QuotaFile* p = (QuotaFile*)pFile;
+  int rc;
+  if (p->quotaObject) {
+    if (p->fileChunkSize > 0) {
+      // Round up to the smallest multiple of the chunk size that will hold all
+      // the data.
+      size =
+          ((size + p->fileChunkSize - 1) / p->fileChunkSize) * p->fileChunkSize;
+    }
+    if (!p->quotaObject->MaybeUpdateSize(size, /* aTruncate */ true)) {
+      return SQLITE_FULL;
+    }
+  }
+  rc = p->pReal->pMethods->xTruncate(p->pReal, size);
+  if (p->quotaObject) {
+    if (rc == SQLITE_OK) {
+#ifdef DEBUG
+      // Make sure xTruncate set the size exactly as we calculated above.
+      sqlite_int64 newSize;
+      MOZ_ASSERT(QuotaFileSize(pFile, &newSize) == SQLITE_OK);
+      MOZ_ASSERT(newSize == size);
+#endif
+    } else {
+      NS_WARNING(
+          "xTruncate failed on a quota-controlled file, attempting to "
+          "update its current size...");
+      if (QuotaFileSize(pFile, &size) == SQLITE_OK) {
+        DebugOnly<bool> res =
+            p->quotaObject->MaybeUpdateSize(size, /* aTruncate */ true);
+        MOZ_ASSERT(res);
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** Sync a QuotaFile.
+*/
+int QuotaSync(sqlite3_file* pFile, int flags) {
+  QuotaFile* p = (QuotaFile*)pFile;
+  return p->pReal->pMethods->xSync(p->pReal, flags);
+}
+
+/*
+** Lock a QuotaFile.
+*/
+int QuotaLock(sqlite3_file* pFile, int eLock) {
+  QuotaFile* p = (QuotaFile*)pFile;
+  int rc;
+  rc = p->pReal->pMethods->xLock(p->pReal, eLock);
+  return rc;
+}
+
+/*
+** Unlock a QuotaFile.
+*/
+int QuotaUnlock(sqlite3_file* pFile, int eLock) {
+  QuotaFile* p = (QuotaFile*)pFile;
+  int rc;
+  rc = p->pReal->pMethods->xUnlock(p->pReal, eLock);
+  return rc;
+}
+
+/*
+** Check if another file-handle holds a RESERVED lock on a QuotaFile.
+*/
+int QuotaCheckReservedLock(sqlite3_file* pFile, int* pResOut) {
+  QuotaFile* p = (QuotaFile*)pFile;
+  int rc = p->pReal->pMethods->xCheckReservedLock(p->pReal, pResOut);
+  return rc;
+}
+
+/*
+** File control method. For custom operations on a QuotaFile.
+*/
+int QuotaFileControl(sqlite3_file* pFile, int op, void* pArg) {
+  QuotaFile* p = (QuotaFile*)pFile;
+  int rc;
+  // Hook SQLITE_FCNTL_SIZE_HINT for quota-controlled files and do the necessary
+  // work before passing to the SQLite VFS.
+  if (op == SQLITE_FCNTL_SIZE_HINT && p->quotaObject) {
+    sqlite3_int64 hintSize = *static_cast<sqlite3_int64*>(pArg);
+    sqlite3_int64 currentSize;
+    rc = QuotaFileSize(pFile, &currentSize);
+    if (rc != SQLITE_OK) {
+      return rc;
+    }
+    if (hintSize > currentSize) {
+      rc = QuotaTruncate(pFile, hintSize);
+      if (rc != SQLITE_OK) {
+        return rc;
+      }
+    }
+  }
+  rc = p->pReal->pMethods->xFileControl(p->pReal, op, pArg);
+  // Grab the file chunk size after the SQLite VFS has approved.
+  if (op == SQLITE_FCNTL_CHUNK_SIZE && rc == SQLITE_OK) {
+    p->fileChunkSize = *static_cast<int*>(pArg);
+  }
+#ifdef DEBUG
+  if (op == SQLITE_FCNTL_SIZE_HINT && p->quotaObject && rc == SQLITE_OK) {
+    sqlite3_int64 hintSize = *static_cast<sqlite3_int64*>(pArg);
+    if (p->fileChunkSize > 0) {
+      hintSize = ((hintSize + p->fileChunkSize - 1) / p->fileChunkSize) *
+                 p->fileChunkSize;
+    }
+    sqlite3_int64 currentSize;
+    MOZ_ASSERT(QuotaFileSize(pFile, &currentSize) == SQLITE_OK);
+    MOZ_ASSERT(currentSize >= hintSize);
+  }
+#endif
+  return rc;
+}
+
+/*
+** Return the sector-size in bytes for a QuotaFile.
+*/
+int QuotaSectorSize(sqlite3_file* pFile) {
+  QuotaFile* p = (QuotaFile*)pFile;
+  int rc;
+  rc = p->pReal->pMethods->xSectorSize(p->pReal);
+  return rc;
+}
+
+/*
+** Return the device characteristic flags supported by a QuotaFile.
+*/
+int QuotaDeviceCharacteristics(sqlite3_file* pFile) {
+  QuotaFile* p = (QuotaFile*)pFile;
+  int rc;
+  rc = p->pReal->pMethods->xDeviceCharacteristics(p->pReal);
+  return rc;
+}
+
+/*
+** Shared-memory operations.
+*/
+int QuotaShmLock(sqlite3_file* pFile, int ofst, int n, int flags) {
+  QuotaFile* p = (QuotaFile*)pFile;
+  return p->pReal->pMethods->xShmLock(p->pReal, ofst, n, flags);
+}
+
+int QuotaShmMap(sqlite3_file* pFile, int iRegion, int szRegion, int isWrite,
+                void volatile** pp) {
+  QuotaFile* p = (QuotaFile*)pFile;
+  int rc;
+  rc = p->pReal->pMethods->xShmMap(p->pReal, iRegion, szRegion, isWrite, pp);
+  return rc;
+}
+
+void QuotaShmBarrier(sqlite3_file* pFile) {
+  QuotaFile* p = (QuotaFile*)pFile;
+  p->pReal->pMethods->xShmBarrier(p->pReal);
+}
+
+int QuotaShmUnmap(sqlite3_file* pFile, int delFlag) {
+  QuotaFile* p = (QuotaFile*)pFile;
+  int rc;
+  rc = p->pReal->pMethods->xShmUnmap(p->pReal, delFlag);
+  return rc;
+}
+
+int QuotaFetch(sqlite3_file* pFile, sqlite3_int64 iOff, int iAmt, void** pp) {
+  QuotaFile* p = (QuotaFile*)pFile;
+  MOZ_ASSERT(p->pReal->pMethods->iVersion >= 3);
+  return p->pReal->pMethods->xFetch(p->pReal, iOff, iAmt, pp);
+}
+
+int QuotaUnfetch(sqlite3_file* pFile, sqlite3_int64 iOff, void* pResOut) {
+  QuotaFile* p = (QuotaFile*)pFile;
+  MOZ_ASSERT(p->pReal->pMethods->iVersion >= 3);
+  return p->pReal->pMethods->xUnfetch(p->pReal, iOff, pResOut);
+}
+
+int QuotaOpen(sqlite3_vfs* vfs, const char* zName, sqlite3_file* pFile,
+              int flags, int* pOutFlags) {
+  sqlite3_vfs* orig_vfs = static_cast<sqlite3_vfs*>(vfs->pAppData);
+  int rc;
+  QuotaFile* p = (QuotaFile*)pFile;
+
+  MaybeEstablishQuotaControl(zName, p, flags);
+
+  rc = orig_vfs->xOpen(orig_vfs, zName, p->pReal, flags, pOutFlags);
+  if (rc != SQLITE_OK) return rc;
+  if (p->pReal->pMethods) {
+    sqlite3_io_methods* pNew = new sqlite3_io_methods;
+    const sqlite3_io_methods* pSub = p->pReal->pMethods;
+    memset(pNew, 0, sizeof(*pNew));
+    // If the io_methods version is higher than the last known one, you should
+    // update this VFS adding appropriate IO methods for any methods added in
+    // the version change.
+    pNew->iVersion = pSub->iVersion;
+    MOZ_ASSERT(pNew->iVersion <= LAST_KNOWN_IOMETHODS_VERSION);
+    pNew->xClose = QuotaClose;
+    pNew->xRead = QuotaRead;
+    pNew->xWrite = QuotaWrite;
+    pNew->xTruncate = QuotaTruncate;
+    pNew->xSync = QuotaSync;
+    pNew->xFileSize = QuotaFileSize;
+    pNew->xLock = QuotaLock;
+    pNew->xUnlock = QuotaUnlock;
+    pNew->xCheckReservedLock = QuotaCheckReservedLock;
+    pNew->xFileControl = QuotaFileControl;
+    pNew->xSectorSize = QuotaSectorSize;
+    pNew->xDeviceCharacteristics = QuotaDeviceCharacteristics;
+    if (pNew->iVersion >= 2) {
+      // Methods added in version 2.
+      pNew->xShmMap = pSub->xShmMap ? QuotaShmMap : nullptr;
+      pNew->xShmLock = pSub->xShmLock ? QuotaShmLock : nullptr;
+      pNew->xShmBarrier = pSub->xShmBarrier ? QuotaShmBarrier : nullptr;
+      pNew->xShmUnmap = pSub->xShmUnmap ? QuotaShmUnmap : nullptr;
+    }
+    if (pNew->iVersion >= 3) {
+      // Methods added in version 3.
+      // SQLite 3.7.17 calls these methods without checking for nullptr first,
+      // so we always define them.  Verify that we're not going to call
+      // nullptrs, though.
+      MOZ_ASSERT(pSub->xFetch);
+      pNew->xFetch = QuotaFetch;
+      MOZ_ASSERT(pSub->xUnfetch);
+      pNew->xUnfetch = QuotaUnfetch;
+    }
+    pFile->pMethods = pNew;
+  }
+  return rc;
+}
+
+int QuotaDelete(sqlite3_vfs* vfs, const char* zName, int syncDir) {
+  sqlite3_vfs* orig_vfs = static_cast<sqlite3_vfs*>(vfs->pAppData);
+  int rc;
+  RefPtr<QuotaObject> quotaObject;
+
+  if (StringEndsWith(nsDependentCString(zName), "-wal"_ns)) {
+    quotaObject = GetQuotaObjectFromName(zName);
+  }
+
+  rc = orig_vfs->xDelete(orig_vfs, zName, syncDir);
+  if (rc == SQLITE_OK && quotaObject) {
+    MOZ_ALWAYS_TRUE(quotaObject->MaybeUpdateSize(0, /* aTruncate */ true));
+  }
+
+  return rc;
+}
+
+int QuotaAccess(sqlite3_vfs* vfs, const char* zName, int flags, int* pResOut) {
+  sqlite3_vfs* orig_vfs = static_cast<sqlite3_vfs*>(vfs->pAppData);
+  return orig_vfs->xAccess(orig_vfs, zName, flags, pResOut);
+}
+
+int QuotaFullPathname(sqlite3_vfs* vfs, const char* zName, int nOut,
+                      char* zOut) {
+#if defined(XP_WIN)
+  // SQLite uses GetFullPathnameW which also normailizes file path. If a file
+  // component ends with a dot, it would be removed. However, it's not desired.
+  //
+  // And that would result SQLite uses wrong database and quotaObject.
+  // Note that we are safe to avoid the GetFullPathnameW call for \\?\ prefixed
+  // paths.
+  // And note that this hack will be removed once the issue is fixed directly in
+  // SQLite.
+
+  // zName that starts with "//?/" is the case when a file URI was passed and
+  // zName that starts with "\\?\" is the case when a normal path was passed
+  // (not file URI).
+  if (StaticPrefs::dom_quotaManager_overrideXFullPathname() &&
+      ((zName[0] == '/' && zName[1] == '/' && zName[2] == '?' &&
+        zName[3] == '/') ||
+       (zName[0] == '\\' && zName[1] == '\\' && zName[2] == '?' &&
+        zName[3] == '\\'))) {
+    MOZ_ASSERT(nOut >= vfs->mxPathname);
+    MOZ_ASSERT(static_cast<size_t>(nOut) > strlen(zName));
+
+    size_t index = 0;
+    while (zName[index] != '\0') {
+      if (zName[index] == '/') {
+        zOut[index] = '\\';
+      } else {
+        zOut[index] = zName[index];
+      }
+
+      index++;
+    }
+    zOut[index] = '\0';
+
+    return SQLITE_OK;
+  }
+#elif defined(XP_UNIX)
+  // SQLite canonicalizes (resolves path components) file paths on Unix which
+  // doesn't work well with file path sanity checks in quota manager. This is
+  // especially a problem on mac where /var is a symlink to /private/var.
+  // Since QuotaVFS is used only by quota clients which never access databases
+  // outside of PROFILE/storage, we override Unix xFullPathname with own
+  // implementation that doesn't do any canonicalization.
+
+  if (StaticPrefs::dom_quotaManager_overrideXFullPathnameUnix()) {
+    if (nOut < 0) {
+      // Match the return code used by SQLite's xFullPathname implementation
+      // here and below.
+      return SQLITE_CANTOPEN;
+    }
+
+    QM_TRY_INSPECT(
+        const auto& path, ([&zName]() -> Result<nsString, nsresult> {
+          NS_ConvertUTF8toUTF16 name(zName);
+
+          if (name.First() == '/') {
+            return std::move(name);
+          }
+
+          QM_TRY_INSPECT(const auto& file,
+                         MOZ_TO_RESULT_INVOKE_TYPED(nsCOMPtr<nsIFile>,
+                                                    NS_GetSpecialDirectory,
+                                                    NS_OS_CURRENT_WORKING_DIR));
+
+          QM_TRY(MOZ_TO_RESULT(file->Append(name)));
+
+          QM_TRY_RETURN(
+              MOZ_TO_RESULT_INVOKE_MEMBER_TYPED(nsString, file, GetPath));
+        }()),
+        SQLITE_CANTOPEN);
+
+    QM_TRY_INSPECT(const auto& quotaFile, QM_NewLocalFile(path),
+                   SQLITE_CANTOPEN);
+
+    QM_TRY_INSPECT(
+        const auto& quotaPath,
+        MOZ_TO_RESULT_INVOKE_MEMBER_TYPED(nsString, quotaFile, GetPath),
+        SQLITE_CANTOPEN);
+
+    NS_ConvertUTF16toUTF8 sqlitePath(quotaPath);
+
+    if (sqlitePath.Length() > (unsigned int)nOut) {
+      return SQLITE_CANTOPEN;
+    }
+
+    nsCharTraits<char>::copy(zOut, sqlitePath.get(), sqlitePath.Length());
+    zOut[sqlitePath.Length()] = '\0';
+
+    return SQLITE_OK;
+  }
+#endif
+
+  sqlite3_vfs* orig_vfs = static_cast<sqlite3_vfs*>(vfs->pAppData);
+  return orig_vfs->xFullPathname(orig_vfs, zName, nOut, zOut);
+}
+
+void* QuotaDlOpen(sqlite3_vfs* vfs, const char* zFilename) {
+  sqlite3_vfs* orig_vfs = static_cast<sqlite3_vfs*>(vfs->pAppData);
+  return orig_vfs->xDlOpen(orig_vfs, zFilename);
+}
+
+void QuotaDlError(sqlite3_vfs* vfs, int nByte, char* zErrMsg) {
+  sqlite3_vfs* orig_vfs = static_cast<sqlite3_vfs*>(vfs->pAppData);
+  orig_vfs->xDlError(orig_vfs, nByte, zErrMsg);
+}
+
+void (*QuotaDlSym(sqlite3_vfs* vfs, void* pHdle, const char* zSym))(void) {
+  sqlite3_vfs* orig_vfs = static_cast<sqlite3_vfs*>(vfs->pAppData);
+  return orig_vfs->xDlSym(orig_vfs, pHdle, zSym);
+}
+
+void QuotaDlClose(sqlite3_vfs* vfs, void* pHandle) {
+  sqlite3_vfs* orig_vfs = static_cast<sqlite3_vfs*>(vfs->pAppData);
+  orig_vfs->xDlClose(orig_vfs, pHandle);
+}
+
+int QuotaRandomness(sqlite3_vfs* vfs, int nByte, char* zOut) {
+  sqlite3_vfs* orig_vfs = static_cast<sqlite3_vfs*>(vfs->pAppData);
+  return orig_vfs->xRandomness(orig_vfs, nByte, zOut);
+}
+
+int QuotaSleep(sqlite3_vfs* vfs, int microseconds) {
+  sqlite3_vfs* orig_vfs = static_cast<sqlite3_vfs*>(vfs->pAppData);
+  return orig_vfs->xSleep(orig_vfs, microseconds);
+}
+
+int QuotaCurrentTime(sqlite3_vfs* vfs, double* prNow) {
+  sqlite3_vfs* orig_vfs = static_cast<sqlite3_vfs*>(vfs->pAppData);
+  return orig_vfs->xCurrentTime(orig_vfs, prNow);
+}
+
+int QuotaGetLastError(sqlite3_vfs* vfs, int nBuf, char* zBuf) {
+  sqlite3_vfs* orig_vfs = static_cast<sqlite3_vfs*>(vfs->pAppData);
+  return orig_vfs->xGetLastError(orig_vfs, nBuf, zBuf);
+}
+
+int QuotaCurrentTimeInt64(sqlite3_vfs* vfs, sqlite3_int64* piNow) {
+  sqlite3_vfs* orig_vfs = static_cast<sqlite3_vfs*>(vfs->pAppData);
+  return orig_vfs->xCurrentTimeInt64(orig_vfs, piNow);
+}
+
+static int QuotaSetSystemCall(sqlite3_vfs* vfs, const char* zName,
+                              sqlite3_syscall_ptr pFunc) {
+  sqlite3_vfs* orig_vfs = static_cast<sqlite3_vfs*>(vfs->pAppData);
+  return orig_vfs->xSetSystemCall(orig_vfs, zName, pFunc);
+}
+
+static sqlite3_syscall_ptr QuotaGetSystemCall(sqlite3_vfs* vfs,
+                                              const char* zName) {
+  sqlite3_vfs* orig_vfs = static_cast<sqlite3_vfs*>(vfs->pAppData);
+  return orig_vfs->xGetSystemCall(orig_vfs, zName);
+}
+
+static const char* QuotaNextSystemCall(sqlite3_vfs* vfs, const char* zName) {
+  sqlite3_vfs* orig_vfs = static_cast<sqlite3_vfs*>(vfs->pAppData);
+  return orig_vfs->xNextSystemCall(orig_vfs, zName);
+}
+
+}  // namespace
+
+namespace mozilla::storage::quotavfs {
+
+const char* GetVFSName() { return "quotavfs"; }
+
+UniquePtr<sqlite3_vfs> ConstructVFS(const char* aBaseVFSName) {
+  MOZ_ASSERT(aBaseVFSName);
+
+  if (sqlite3_vfs_find(GetVFSName()) != nullptr) {
+    return nullptr;
+  }
+  sqlite3_vfs* vfs = sqlite3_vfs_find(aBaseVFSName);
+  if (!vfs) {
+    return nullptr;
+  }
+
+  auto qvfs = MakeUnique<sqlite3_vfs>();
+  memset(qvfs.get(), 0, sizeof(::sqlite3_vfs));
+  // If the VFS version is higher than the last known one, you should update
+  // this VFS adding appropriate methods for any methods added in the version
+  // change.
+  qvfs->iVersion = vfs->iVersion;
+  MOZ_ASSERT(vfs->iVersion <= LAST_KNOWN_VFS_VERSION);
+  qvfs->szOsFile = static_cast<int>(sizeof(QuotaFile) - sizeof(sqlite3_file) +
+                                    vfs->szOsFile);
+  qvfs->mxPathname = vfs->mxPathname;
+  qvfs->zName = GetVFSName();
+  qvfs->pAppData = vfs;
+  qvfs->xOpen = QuotaOpen;
+  qvfs->xDelete = QuotaDelete;
+  qvfs->xAccess = QuotaAccess;
+  qvfs->xFullPathname = QuotaFullPathname;
+  qvfs->xDlOpen = QuotaDlOpen;
+  qvfs->xDlError = QuotaDlError;
+  qvfs->xDlSym = QuotaDlSym;
+  qvfs->xDlClose = QuotaDlClose;
+  qvfs->xRandomness = QuotaRandomness;
+  qvfs->xSleep = QuotaSleep;
+  qvfs->xCurrentTime = QuotaCurrentTime;
+  qvfs->xGetLastError = QuotaGetLastError;
+  if (qvfs->iVersion >= 2) {
+    // Methods added in version 2.
+    qvfs->xCurrentTimeInt64 = QuotaCurrentTimeInt64;
+  }
+  if (qvfs->iVersion >= 3) {
+    // Methods added in version 3.
+    qvfs->xSetSystemCall = QuotaSetSystemCall;
+    qvfs->xGetSystemCall = QuotaGetSystemCall;
+    qvfs->xNextSystemCall = QuotaNextSystemCall;
+  }
+  return qvfs;
+}
+
+already_AddRefed<QuotaObject> GetQuotaObjectForFile(sqlite3_file* pFile) {
+  MOZ_ASSERT(pFile);
+
+  QuotaFile* p = (QuotaFile*)pFile;
+  RefPtr<QuotaObject> result = p->quotaObject;
+  return result.forget();
+}
+
+}  // namespace mozilla::storage::quotavfs
diff --git a/storage/QuotaVFS.h b/storage/QuotaVFS.h
new file mode 100644
index 0000000000..32fb8ac3a8
--- /dev/null
+++ b/storage/QuotaVFS.h
@@ -0,0 +1,33 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef STORAGE_QUOTAVFS_H_
+#define STORAGE_QUOTAVFS_H_
+
+#include "mozilla/UniquePtr.h"
+
+struct sqlite3_vfs;
+struct sqlite3_file;
+
+template <typename T>
+struct already_AddRefed;
+
+namespace mozilla::dom::quota {
+class QuotaObject;
+}
+
+namespace mozilla::storage::quotavfs {
+
+const char* GetVFSName();
+
+UniquePtr<sqlite3_vfs> ConstructVFS(const char* aBaseVFSName);
+
+already_AddRefed<dom::quota::QuotaObject> GetQuotaObjectForFile(
+    sqlite3_file* pFile);
+
+}  // namespace mozilla::storage::quotavfs
+
+#endif  // STORAGE_QUOTAVFS_H_
diff --git a/storage/ReadOnlyNoLockVFS.cpp b/storage/ReadOnlyNoLockVFS.cpp
new file mode 100644
index 0000000000..9a820085ed
--- /dev/null
+++ b/storage/ReadOnlyNoLockVFS.cpp
@@ -0,0 +1,130 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This VFS is built on top of the (unix|win32)-none, but it additionally
+ * sets any opened file as immutable, that allows to also open in read-only
+ * mode databases using WAL, or other journals that need auxiliary files, when
+ * such files cannot be created.
+ * This is useful when trying to read from third-party databases, avoiding any
+ * risk of creating auxiliary files (e.g. journals).
+ * It can only be used on read-only connections, because being a no-lock VFS
+ * it would be trivial to corrupt the data.
+ */
+
+#include "nsDebug.h"
+#include "sqlite3.h"
+
+#define ORIGVFS(p) ((sqlite3_vfs*)((p)->pAppData))
+
+#if defined(XP_WIN)
+#  define BASE_VFS "win32-none"
+#else
+#  define BASE_VFS "unix-none"
+#endif
+
+#define VFS_NAME "readonly-immutable-nolock"
+
+namespace {
+
+static int vfsOpen(sqlite3_vfs* vfs, const char* zName, sqlite3_file* pFile,
+                   int flags, int* pOutFlags) {
+  if ((flags & SQLITE_OPEN_READONLY) == 0) {
+    // This is not done to be used in readwrite connections.
+    return SQLITE_CANTOPEN;
+  }
+
+  sqlite3_vfs* pOrigVfs = ORIGVFS(vfs);
+  int rc = pOrigVfs->xOpen(pOrigVfs, zName, pFile, flags, pOutFlags);
+  if (rc != SQLITE_OK) {
+    return rc;
+  }
+
+  const sqlite3_io_methods* pOrigMethods = pFile->pMethods;
+
+  // If the IO version is higher than the last known one, you should update
+  // this IO adding appropriate methods for any methods added in the version
+  // change.
+  MOZ_ASSERT(pOrigMethods->iVersion <= 3);
+
+  static const sqlite3_io_methods vfs_io_methods = {
+      pOrigMethods->iVersion,           /* iVersion */
+      pOrigMethods->xClose,             /* xClose */
+      pOrigMethods->xRead,              /* xRead */
+      pOrigMethods->xWrite,             /* xWrite */
+      pOrigMethods->xTruncate,          /* xTruncate */
+      pOrigMethods->xSync,              /* xSync */
+      pOrigMethods->xFileSize,          /* xFileSize */
+      pOrigMethods->xLock,              /* xLock */
+      pOrigMethods->xUnlock,            /* xUnlock */
+      pOrigMethods->xCheckReservedLock, /* xCheckReservedLock */
+      pOrigMethods->xFileControl,       /* xFileControl */
+      pOrigMethods->xSectorSize,        /* xSectorSize */
+      [](sqlite3_file*) {
+        return SQLITE_IOCAP_IMMUTABLE;
+      },                         /* xDeviceCharacteristics */
+      pOrigMethods->xShmMap,     /* xShmMap */
+      pOrigMethods->xShmLock,    /* xShmLock */
+      pOrigMethods->xShmBarrier, /* xShmBarrier */
+      pOrigMethods->xShmUnmap,   /* xShmUnmap */
+      pOrigMethods->xFetch,      /* xFetch */
+      pOrigMethods->xUnfetch     /* xUnfetch */
+  };
+  pFile->pMethods = &vfs_io_methods;
+  if (pOutFlags) {
+    *pOutFlags = flags;
+  }
+
+  return SQLITE_OK;
+}
+
+}  // namespace
+
+namespace mozilla::storage {
+
+UniquePtr<sqlite3_vfs> ConstructReadOnlyNoLockVFS() {
+  if (sqlite3_vfs_find(VFS_NAME) != nullptr) {
+    return nullptr;
+  }
+  sqlite3_vfs* pOrigVfs = sqlite3_vfs_find(BASE_VFS);
+  if (!pOrigVfs) {
+    return nullptr;
+  }
+
+  // If the VFS version is higher than the last known one, you should update
+  // this VFS adding appropriate methods for any methods added in the version
+  // change.
+  MOZ_ASSERT(pOrigVfs->iVersion <= 3);
+
+  static const sqlite3_vfs vfs = {
+      pOrigVfs->iVersion,          /* iVersion  */
+      pOrigVfs->szOsFile,          /* szOsFile */
+      pOrigVfs->mxPathname,        /* mxPathname */
+      nullptr,                     /* pNext */
+      VFS_NAME,                    /* zName */
+      pOrigVfs,                    /* pAppData */
+      vfsOpen,                     /* xOpen */
+      pOrigVfs->xDelete,           /* xDelete */
+      pOrigVfs->xAccess,           /* xAccess */
+      pOrigVfs->xFullPathname,     /* xFullPathname */
+      pOrigVfs->xDlOpen,           /* xDlOpen */
+      pOrigVfs->xDlError,          /* xDlError */
+      pOrigVfs->xDlSym,            /* xDlSym */
+      pOrigVfs->xDlClose,          /* xDlClose */
+      pOrigVfs->xRandomness,       /* xRandomness */
+      pOrigVfs->xSleep,            /* xSleep */
+      pOrigVfs->xCurrentTime,      /* xCurrentTime */
+      pOrigVfs->xGetLastError,     /* xGetLastError */
+      pOrigVfs->xCurrentTimeInt64, /* xCurrentTimeInt64 */
+      pOrigVfs->xSetSystemCall,    /* xSetSystemCall */
+      pOrigVfs->xGetSystemCall,    /* xGetSystemCall */
+      pOrigVfs->xNextSystemCall    /* xNextSystemCall */
+  };
+
+  return MakeUnique<sqlite3_vfs>(vfs);
+}
+
+}  // namespace mozilla::storage
diff --git a/storage/SQLCollations.cpp b/storage/SQLCollations.cpp
new file mode 100644
index 0000000000..3cbeafe5d0
--- /dev/null
+++ b/storage/SQLCollations.cpp
@@ -0,0 +1,183 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/intl/Collator.h"
+
+#include "SQLCollations.h"
+
+using mozilla::intl::Collator;
+
+namespace mozilla {
+namespace storage {
+
+////////////////////////////////////////////////////////////////////////////////
+//// Local Helper Functions
+
+namespace {
+
+/**
+ * Helper function for the UTF-8 locale collations.
+ *
+ * @param  aService
+ *         The Service that owns the collator used by this collation.
+ * @param  aLen1
+ *         The number of bytes in aStr1.
+ * @param  aStr1
+ *         The string to be compared against aStr2 as provided by SQLite.  It
+ *         must be a non-null-terminated char* buffer.
+ * @param  aLen2
+ *         The number of bytes in aStr2.
+ * @param  aStr2
+ *         The string to be compared against aStr1 as provided by SQLite.  It
+ *         must be a non-null-terminated char* buffer.
+ * @param  aSensitivity
+ *         The sorting sensitivity.
+ * @return aStr1 - aStr2.  That is, if aStr1 < aStr2, returns a negative number.
+ *         If aStr1 > aStr2, returns a positive number.  If aStr1 == aStr2,
+ *         returns 0.
+ */
+int localeCollationHelper8(void* aService, int aLen1, const void* aStr1,
+                           int aLen2, const void* aStr2,
+                           Collator::Sensitivity aSensitivity) {
+  NS_ConvertUTF8toUTF16 str1(static_cast<const char*>(aStr1), aLen1);
+  NS_ConvertUTF8toUTF16 str2(static_cast<const char*>(aStr2), aLen2);
+  Service* serv = static_cast<Service*>(aService);
+  return serv->localeCompareStrings(str1, str2, aSensitivity);
+}
+
+/**
+ * Helper function for the UTF-16 locale collations.
+ *
+ * @param  aService
+ *         The Service that owns the collator used by this collation.
+ * @param  aLen1
+ *         The number of bytes (not characters) in aStr1.
+ * @param  aStr1
+ *         The string to be compared against aStr2 as provided by SQLite.  It
+ *         must be a non-null-terminated char16_t* buffer.
+ * @param  aLen2
+ *         The number of bytes (not characters) in aStr2.
+ * @param  aStr2
+ *         The string to be compared against aStr1 as provided by SQLite.  It
+ *         must be a non-null-terminated char16_t* buffer.
+ * @param  aSensitivity
+ *         The sorting sensitivity.
+ * @return aStr1 - aStr2.  That is, if aStr1 < aStr2, returns a negative number.
+ *         If aStr1 > aStr2, returns a positive number.  If aStr1 == aStr2,
+ *         returns 0.
+ */
+int localeCollationHelper16(void* aService, int aLen1, const void* aStr1,
+                            int aLen2, const void* aStr2,
+                            Collator::Sensitivity aSensitivity) {
+  const char16_t* buf1 = static_cast<const char16_t*>(aStr1);
+  const char16_t* buf2 = static_cast<const char16_t*>(aStr2);
+
+  // The second argument to the nsDependentSubstring constructor is exclusive:
+  // It points to the char16_t immediately following the last one in the target
+  // substring.  Since aLen1 and aLen2 are in bytes, divide by sizeof(char16_t)
+  // so that the pointer arithmetic is correct.
+  nsDependentSubstring str1(buf1, buf1 + (aLen1 / sizeof(char16_t)));
+  nsDependentSubstring str2(buf2, buf2 + (aLen2 / sizeof(char16_t)));
+  Service* serv = static_cast<Service*>(aService);
+  return serv->localeCompareStrings(str1, str2, aSensitivity);
+}
+
+// This struct is used only by registerCollations below, but ISO C++98 forbids
+// instantiating a template dependent on a locally-defined type.  Boo-urns!
+struct Collations {
+  const char* zName;
+  int enc;
+  int (*xCompare)(void*, int, const void*, int, const void*);
+};
+
+}  // namespace
+
+////////////////////////////////////////////////////////////////////////////////
+//// Exposed Functions
+
+int registerCollations(sqlite3* aDB, Service* aService) {
+  Collations collations[] = {
+      {"locale", SQLITE_UTF8, localeCollation8},
+      {"locale_case_sensitive", SQLITE_UTF8, localeCollationCaseSensitive8},
+      {"locale_accent_sensitive", SQLITE_UTF8, localeCollationAccentSensitive8},
+      {"locale_case_accent_sensitive", SQLITE_UTF8,
+       localeCollationCaseAccentSensitive8},
+      {"locale", SQLITE_UTF16, localeCollation16},
+      {"locale_case_sensitive", SQLITE_UTF16, localeCollationCaseSensitive16},
+      {"locale_accent_sensitive", SQLITE_UTF16,
+       localeCollationAccentSensitive16},
+      {"locale_case_accent_sensitive", SQLITE_UTF16,
+       localeCollationCaseAccentSensitive16},
+  };
+
+  int rv = SQLITE_OK;
+  for (size_t i = 0; SQLITE_OK == rv && i < ArrayLength(collations); ++i) {
+    struct Collations* p = &collations[i];
+    rv = ::sqlite3_create_collation(aDB, p->zName, p->enc, aService,
+                                    p->xCompare);
+  }
+
+  return rv;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// SQL Collations
+
+int localeCollation8(void* aService, int aLen1, const void* aStr1, int aLen2,
+                     const void* aStr2) {
+  return localeCollationHelper8(aService, aLen1, aStr1, aLen2, aStr2,
+                                Collator::Sensitivity::Base);
+}
+
+int localeCollationCaseSensitive8(void* aService, int aLen1, const void* aStr1,
+                                  int aLen2, const void* aStr2) {
+  return localeCollationHelper8(aService, aLen1, aStr1, aLen2, aStr2,
+                                Collator::Sensitivity::Case);
+}
+
+int localeCollationAccentSensitive8(void* aService, int aLen1,
+                                    const void* aStr1, int aLen2,
+                                    const void* aStr2) {
+  return localeCollationHelper8(aService, aLen1, aStr1, aLen2, aStr2,
+                                Collator::Sensitivity::Accent);
+}
+
+int localeCollationCaseAccentSensitive8(void* aService, int aLen1,
+                                        const void* aStr1, int aLen2,
+                                        const void* aStr2) {
+  return localeCollationHelper8(aService, aLen1, aStr1, aLen2, aStr2,
+                                Collator::Sensitivity::Variant);
+}
+
+int localeCollation16(void* aService, int aLen1, const void* aStr1, int aLen2,
+                      const void* aStr2) {
+  return localeCollationHelper16(aService, aLen1, aStr1, aLen2, aStr2,
+                                 Collator::Sensitivity::Base);
+}
+
+int localeCollationCaseSensitive16(void* aService, int aLen1, const void* aStr1,
+                                   int aLen2, const void* aStr2) {
+  return localeCollationHelper16(aService, aLen1, aStr1, aLen2, aStr2,
+                                 Collator::Sensitivity::Case);
+}
+
+int localeCollationAccentSensitive16(void* aService, int aLen1,
+                                     const void* aStr1, int aLen2,
+                                     const void* aStr2) {
+  return localeCollationHelper16(aService, aLen1, aStr1, aLen2, aStr2,
+                                 Collator::Sensitivity::Accent);
+}
+
+int localeCollationCaseAccentSensitive16(void* aService, int aLen1,
+                                         const void* aStr1, int aLen2,
+                                         const void* aStr2) {
+  return localeCollationHelper16(aService, aLen1, aStr1, aLen2, aStr2,
+                                 Collator::Sensitivity::Variant);
+}
+
+}  // namespace storage
+}  // namespace mozilla
diff --git a/storage/SQLCollations.h b/storage/SQLCollations.h
new file mode 100644
index 0000000000..1845084621
--- /dev/null
+++ b/storage/SQLCollations.h
@@ -0,0 +1,229 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_storage_SQLCollations_h
+#define mozilla_storage_SQLCollations_h
+
+#include "mozStorageService.h"
+#include "nscore.h"
+#include "nsString.h"
+
+#include "sqlite3.h"
+
+namespace mozilla {
+namespace storage {
+
+/**
+ * Registers the collating sequences declared here with the specified
+ * database and Service.
+ *
+ * @param  aDB
+ *         The database we'll be registering the collations with.
+ * @param  aService
+ *         The Service that owns the collator used by our collations.
+ * @return the SQLite status code indicating success or failure.
+ */
+int registerCollations(sqlite3* aDB, Service* aService);
+
+////////////////////////////////////////////////////////////////////////////////
+//// Predefined Functions
+
+/**
+ * Custom UTF-8 collating sequence that respects the application's locale.
+ * Comparison is case- and accent-insensitive.  This is called by SQLite.
+ *
+ * @param  aService
+ *         The Service that owns the collator used by this collation.
+ * @param  aLen1
+ *         The number of bytes in aStr1.
+ * @param  aStr1
+ *         The string to be compared against aStr2.  It will be passed in by
+ *         SQLite as a non-null-terminated char* buffer.
+ * @param  aLen2
+ *         The number of bytes in aStr2.
+ * @param  aStr2
+ *         The string to be compared against aStr1.  It will be passed in by
+ *         SQLite as a non-null-terminated char* buffer.
+ * @return aStr1 - aStr2.  That is, if aStr1 < aStr2, returns a negative number.
+ *         If aStr1 > aStr2, returns a positive number.  If aStr1 == aStr2,
+ *         returns 0.
+ */
+int localeCollation8(void* aService, int aLen1, const void* aStr1, int aLen2,
+                     const void* aStr2);
+
+/**
+ * Custom UTF-8 collating sequence that respects the application's locale.
+ * Comparison is case-sensitive and accent-insensitive.  This is called by
+ * SQLite.
+ *
+ * @param  aService
+ *         The Service that owns the collator used by this collation.
+ * @param  aLen1
+ *         The number of bytes in aStr1.
+ * @param  aStr1
+ *         The string to be compared against aStr2.  It will be passed in by
+ *         SQLite as a non-null-terminated char* buffer.
+ * @param  aLen2
+ *         The number of bytes in aStr2.
+ * @param  aStr2
+ *         The string to be compared against aStr1.  It will be passed in by
+ *         SQLite as a non-null-terminated char* buffer.
+ * @return aStr1 - aStr2.  That is, if aStr1 < aStr2, returns a negative number.
+ *         If aStr1 > aStr2, returns a positive number.  If aStr1 == aStr2,
+ *         returns 0.
+ */
+int localeCollationCaseSensitive8(void* aService, int aLen1, const void* aStr1,
+                                  int aLen2, const void* aStr2);
+
+/**
+ * Custom UTF-8 collating sequence that respects the application's locale.
+ * Comparison is case-insensitive and accent-sensitive.  This is called by
+ * SQLite.
+ *
+ * @param  aService
+ *         The Service that owns the collator used by this collation.
+ * @param  aLen1
+ *         The number of bytes in aStr1.
+ * @param  aStr1
+ *         The string to be compared against aStr2.  It will be passed in by
+ *         SQLite as a non-null-terminated char* buffer.
+ * @param  aLen2
+ *         The number of bytes in aStr2.
+ * @param  aStr2
+ *         The string to be compared against aStr1.  It will be passed in by
+ *         SQLite as a non-null-terminated char* buffer.
+ * @return aStr1 - aStr2.  That is, if aStr1 < aStr2, returns a negative number.
+ *         If aStr1 > aStr2, returns a positive number.  If aStr1 == aStr2,
+ *         returns 0.
+ */
+int localeCollationAccentSensitive8(void* aService, int aLen1,
+                                    const void* aStr1, int aLen2,
+                                    const void* aStr2);
+
+/**
+ * Custom UTF-8 collating sequence that respects the application's locale.
+ * Comparison is case- and accent-sensitive.  This is called by SQLite.
+ *
+ * @param  aService
+ *         The Service that owns the collator used by this collation.
+ * @param  aLen1
+ *         The number of bytes in aStr1.
+ * @param  aStr1
+ *         The string to be compared against aStr2.  It will be passed in by
+ *         SQLite as a non-null-terminated char* buffer.
+ * @param  aLen2
+ *         The number of bytes in aStr2.
+ * @param  aStr2
+ *         The string to be compared against aStr1.  It will be passed in by
+ *         SQLite as a non-null-terminated char* buffer.
+ * @return aStr1 - aStr2.  That is, if aStr1 < aStr2, returns a negative number.
+ *         If aStr1 > aStr2, returns a positive number.  If aStr1 == aStr2,
+ *         returns 0.
+ */
+int localeCollationCaseAccentSensitive8(void* aService, int aLen1,
+                                        const void* aStr1, int aLen2,
+                                        const void* aStr2);
+
+/**
+ * Custom UTF-16 collating sequence that respects the application's locale.
+ * Comparison is case- and accent-insensitive.  This is called by SQLite.
+ *
+ * @param  aService
+ *         The Service that owns the collator used by this collation.
+ * @param  aLen1
+ *         The number of bytes (not characters) in aStr1.
+ * @param  aStr1
+ *         The string to be compared against aStr2.  It will be passed in by
+ *         SQLite as a non-null-terminated char16_t* buffer.
+ * @param  aLen2
+ *         The number of bytes (not characters) in aStr2.
+ * @param  aStr2
+ *         The string to be compared against aStr1.  It will be passed in by
+ *         SQLite as a non-null-terminated char16_t* buffer.
+ * @return aStr1 - aStr2.  That is, if aStr1 < aStr2, returns a negative number.
+ *         If aStr1 > aStr2, returns a positive number.  If aStr1 == aStr2,
+ *         returns 0.
+ */
+int localeCollation16(void* aService, int aLen1, const void* aStr1, int aLen2,
+                      const void* aStr2);
+
+/**
+ * Custom UTF-16 collating sequence that respects the application's locale.
+ * Comparison is case-sensitive and accent-insensitive.  This is called by
+ * SQLite.
+ *
+ * @param  aService
+ *         The Service that owns the collator used by this collation.
+ * @param  aLen1
+ *         The number of bytes (not characters) in aStr1.
+ * @param  aStr1
+ *         The string to be compared against aStr2.  It will be passed in by
+ *         SQLite as a non-null-terminated char16_t* buffer.
+ * @param  aLen2
+ *         The number of bytes (not characters) in aStr2.
+ * @param  aStr2
+ *         The string to be compared against aStr1.  It will be passed in by
+ *         SQLite as a non-null-terminated char16_t* buffer.
+ * @return aStr1 - aStr2.  That is, if aStr1 < aStr2, returns a negative number.
+ *         If aStr1 > aStr2, returns a positive number.  If aStr1 == aStr2,
+ *         returns 0.
+ */
+int localeCollationCaseSensitive16(void* aService, int aLen1, const void* aStr1,
+                                   int aLen2, const void* aStr2);
+
+/**
+ * Custom UTF-16 collating sequence that respects the application's locale.
+ * Comparison is case-insensitive and accent-sensitive.  This is called by
+ * SQLite.
+ *
+ * @param  aService
+ *         The Service that owns the collator used by this collation.
+ * @param  aLen1
+ *         The number of bytes (not characters) in aStr1.
+ * @param  aStr1
+ *         The string to be compared against aStr2.  It will be passed in by
+ *         SQLite as a non-null-terminated char16_t* buffer.
+ * @param  aLen2
+ *         The number of bytes (not characters) in aStr2.
+ * @param  aStr2
+ *         The string to be compared against aStr1.  It will be passed in by
+ *         SQLite as a non-null-terminated char16_t* buffer.
+ * @return aStr1 - aStr2.  That is, if aStr1 < aStr2, returns a negative number.
+ *         If aStr1 > aStr2, returns a positive number.  If aStr1 == aStr2,
+ *         returns 0.
+ */
+int localeCollationAccentSensitive16(void* aService, int aLen1,
+                                     const void* aStr1, int aLen2,
+                                     const void* aStr2);
+
+/**
+ * Custom UTF-16 collating sequence that respects the application's locale.
+ * Comparison is case- and accent-sensitive.  This is called by SQLite.
+ *
+ * @param  aService
+ *         The Service that owns the collator used by this collation.
+ * @param  aLen1
+ *         The number of bytes (not characters) in aStr1.
+ * @param  aStr1
+ *         The string to be compared against aStr2.  It will be passed in by
+ *         SQLite as a non-null-terminated char16_t* buffer.
+ * @param  aLen2
+ *         The number of bytes (not characters) in aStr2.
+ * @param  aStr2
+ *         The string to be compared against aStr1.  It will be passed in by
+ *         SQLite as a non-null-terminated char16_t* buffer.
+ * @return aStr1 - aStr2.  That is, if aStr1 < aStr2, returns a negative number.
+ *         If aStr1 > aStr2, returns a positive number.  If aStr1 == aStr2,
+ *         returns 0.
+ */
+int localeCollationCaseAccentSensitive16(void* aService, int aLen1,
+                                         const void* aStr1, int aLen2,
+                                         const void* aStr2);
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif  // mozilla_storage_SQLCollations_h
diff --git a/storage/SQLiteMutex.h b/storage/SQLiteMutex.h
new file mode 100644
index 0000000000..b7198b1912
--- /dev/null
+++ b/storage/SQLiteMutex.h
@@ -0,0 +1,143 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_storage_SQLiteMutex_h_
+#define mozilla_storage_SQLiteMutex_h_
+
+#include "mozilla/BlockingResourceBase.h"
+#include "sqlite3.h"
+
+namespace mozilla {
+namespace storage {
+
+/**
+ * Wrapper class for sqlite3_mutexes.  To be used whenever we want to use a
+ * sqlite3_mutex.
+ *
+ * @warning Never EVER wrap the same sqlite3_mutex with a different SQLiteMutex.
+ *          If you do this, you void the deadlock detector's warranty!
+ */
+class SQLiteMutex : private BlockingResourceBase {
+ public:
+  /**
+   * Constructs a wrapper for a sqlite3_mutex that has deadlock detecting.
+   *
+   * @param aName
+   *        A name which can be used to reference this mutex.
+   */
+  explicit SQLiteMutex(const char* aName)
+      : BlockingResourceBase(aName, eMutex), mMutex(nullptr) {}
+
+  /**
+   * Sets the mutex that we are wrapping.  We generally do not have access to
+   * our mutex at class construction, so we have to set it once we get access to
+   * it.
+   *
+   * @param aMutex
+   *        The sqlite3_mutex that we are going to wrap.
+   */
+  void initWithMutex(sqlite3_mutex* aMutex) {
+    MOZ_ASSERT(aMutex, "You must pass in a valid mutex!");
+    MOZ_ASSERT(!mMutex, "A mutex has already been set for this!");
+    mMutex = aMutex;
+  }
+
+  /**
+   * After a connection has been successfully closed, its mutex is a dangling
+   * pointer, and as such it should be destroyed.
+   */
+  void destroy() { mMutex = NULL; }
+
+  /**
+   * Acquires the mutex.
+   */
+  void lock() {
+    MOZ_ASSERT(mMutex, "No mutex associated with this wrapper!");
+#if defined(DEBUG)
+    // While SQLite Mutexes may be recursive, in our own code we do not want to
+    // treat them as such.
+    CheckAcquire();
+#endif
+
+    ::sqlite3_mutex_enter(mMutex);
+
+#if defined(DEBUG)
+    Acquire();  // Call is protected by us holding the mutex.
+#endif
+  }
+
+  /**
+   * Releases the mutex.
+   */
+  void unlock() {
+    MOZ_ASSERT(mMutex, "No mutex associated with this wrapper!");
+#if defined(DEBUG)
+    // While SQLite Mutexes may be recursive, in our own code we do not want to
+    // treat them as such.
+    Release();  // Call is protected by us holding the mutex.
+#endif
+
+    ::sqlite3_mutex_leave(mMutex);
+  }
+
+  /**
+   * Asserts that the current thread owns the mutex.
+   */
+  void assertCurrentThreadOwns() {
+    MOZ_ASSERT(mMutex, "No mutex associated with this wrapper!");
+    MOZ_ASSERT(::sqlite3_mutex_held(mMutex),
+               "Mutex is not held, but we expect it to be!");
+  }
+
+  /**
+   * Asserts that the current thread does not own the mutex.
+   */
+  void assertNotCurrentThreadOwns() {
+    MOZ_ASSERT(mMutex, "No mutex associated with this wrapper!");
+    MOZ_ASSERT(::sqlite3_mutex_notheld(mMutex),
+               "Mutex is held, but we expect it to not be!");
+  }
+
+ private:
+  sqlite3_mutex* mMutex;
+};
+
+/**
+ * Automatically acquires the mutex when it enters scope, and releases it when
+ * it leaves scope.
+ */
+class MOZ_STACK_CLASS SQLiteMutexAutoLock {
+ public:
+  explicit SQLiteMutexAutoLock(SQLiteMutex& aMutex) : mMutex(aMutex) {
+    mMutex.lock();
+  }
+
+  ~SQLiteMutexAutoLock() { mMutex.unlock(); }
+
+ private:
+  SQLiteMutex& mMutex;
+};
+
+/**
+ * Automatically releases the mutex when it enters scope, and acquires it when
+ * it leaves scope.
+ */
+class MOZ_STACK_CLASS SQLiteMutexAutoUnlock {
+ public:
+  explicit SQLiteMutexAutoUnlock(SQLiteMutex& aMutex) : mMutex(aMutex) {
+    mMutex.unlock();
+  }
+
+  ~SQLiteMutexAutoUnlock() { mMutex.lock(); }
+
+ private:
+  SQLiteMutex& mMutex;
+};
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif  // mozilla_storage_SQLiteMutex_h_
diff --git a/storage/StatementCache.h b/storage/StatementCache.h
new file mode 100644
index 0000000000..3d07c4ef57
--- /dev/null
+++ b/storage/StatementCache.h
@@ -0,0 +1,129 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_storage_StatementCache_h
+#define mozilla_storage_StatementCache_h
+
+#include "mozIStorageConnection.h"
+#include "mozIStorageStatement.h"
+#include "mozIStorageAsyncStatement.h"
+
+#include "nsHashKeys.h"
+#include "nsInterfaceHashtable.h"
+
+namespace mozilla {
+namespace storage {
+
+/**
+ * Class used to cache statements (mozIStorageStatement or
+ * mozIStorageAsyncStatement).
+ */
+template <typename StatementType>
+class StatementCache {
+ public:
+  /**
+   * Constructor for the cache.
+   *
+   * @note a connection can have more than one cache.
+   *
+   * @param aConnection
+   *        A reference to the nsCOMPtr for the connection this cache is to be
+   *        used for.  This nsCOMPtr must at least live as long as this class,
+   *        otherwise crashes will happen.
+   */
+  explicit StatementCache(nsCOMPtr<mozIStorageConnection>& aConnection)
+      : mConnection(aConnection) {}
+
+  /**
+   * Obtains a cached statement.  If this statement is not yet created, it will
+   * be created and stored for later use.
+   *
+   * @param aQuery
+   *        The SQL string (either a const char [] or nsACString) to get a
+   *        cached query for.
+   * @return the cached statement, or null upon error.
+   */
+  inline already_AddRefed<StatementType> GetCachedStatement(
+      const nsACString& aQuery) {
+    nsCOMPtr<StatementType> stmt;
+    if (!mCachedStatements.Get(aQuery, getter_AddRefs(stmt))) {
+      stmt = CreateStatement(aQuery);
+      NS_ENSURE_TRUE(stmt, nullptr);
+
+      mCachedStatements.InsertOrUpdate(aQuery, stmt);
+    }
+    return stmt.forget();
+  }
+
+  template <int N>
+  MOZ_ALWAYS_INLINE already_AddRefed<StatementType> GetCachedStatement(
+      const char (&aQuery)[N]) {
+    nsDependentCString query(aQuery, N - 1);
+    return GetCachedStatement(query);
+  }
+
+  /**
+   * Finalizes all cached statements so the database can be safely closed.  The
+   * behavior of this cache is unspecified after this method is called.
+   */
+  inline void FinalizeStatements() {
+    for (const auto& data : mCachedStatements.Values()) {
+      (void)data->Finalize();
+    }
+
+    // Clear the cache at this time too!
+    (void)mCachedStatements.Clear();
+  }
+
+ private:
+  inline already_AddRefed<StatementType> CreateStatement(
+      const nsACString& aQuery);
+
+  nsInterfaceHashtable<nsCStringHashKey, StatementType> mCachedStatements;
+  nsCOMPtr<mozIStorageConnection>& mConnection;
+};
+
+template <>
+inline already_AddRefed<mozIStorageStatement>
+StatementCache<mozIStorageStatement>::CreateStatement(
+    const nsACString& aQuery) {
+  NS_ENSURE_TRUE(mConnection, nullptr);
+
+  nsCOMPtr<mozIStorageStatement> stmt;
+  nsresult rv = mConnection->CreateStatement(aQuery, getter_AddRefs(stmt));
+  if (NS_FAILED(rv)) {
+    nsCString error;
+    error.AppendLiteral("The statement '");
+    error.Append(aQuery);
+    error.AppendLiteral("' failed to compile with the error message '");
+    nsCString msg;
+    (void)mConnection->GetLastErrorString(msg);
+    error.Append(msg);
+    error.AppendLiteral("'.");
+    NS_ERROR(error.get());
+  }
+  NS_ENSURE_SUCCESS(rv, nullptr);
+
+  return stmt.forget();
+}
+
+template <>
+inline already_AddRefed<mozIStorageAsyncStatement>
+StatementCache<mozIStorageAsyncStatement>::CreateStatement(
+    const nsACString& aQuery) {
+  NS_ENSURE_TRUE(mConnection, nullptr);
+
+  nsCOMPtr<mozIStorageAsyncStatement> stmt;
+  nsresult rv = mConnection->CreateAsyncStatement(aQuery, getter_AddRefs(stmt));
+  NS_ENSURE_SUCCESS(rv, nullptr);
+
+  return stmt.forget();
+}
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif  // mozilla_storage_StatementCache_h
diff --git a/storage/StorageBaseStatementInternal.cpp b/storage/StorageBaseStatementInternal.cpp
new file mode 100644
index 0000000000..af7425c1cc
--- /dev/null
+++ b/storage/StorageBaseStatementInternal.cpp
@@ -0,0 +1,221 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 sts=2 expandtab
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "StorageBaseStatementInternal.h"
+
+#include "nsProxyRelease.h"
+
+#include "mozStorageBindingParamsArray.h"
+#include "mozStorageStatementData.h"
+#include "mozStorageAsyncStatementExecution.h"
+
+namespace mozilla {
+namespace storage {
+
+////////////////////////////////////////////////////////////////////////////////
+//// Local Classes
+
+/**
+ * Used to finalize an asynchronous statement on the background thread.
+ */
+class AsyncStatementFinalizer : public Runnable {
+ public:
+  /**
+   * Constructor for the event.
+   *
+   * @param aStatement
+   *        We need the AsyncStatement to be able to get at the sqlite3_stmt;
+   *        we only access/create it on the async event target.
+   * @param aConnection
+   *        We need the connection to know what event target to release the
+   *        statement on. We release the statement on that event target since
+   *        releasing the statement might end up releasing the connection too.
+   */
+  AsyncStatementFinalizer(StorageBaseStatementInternal* aStatement,
+                          Connection* aConnection)
+      : Runnable("storage::AsyncStatementFinalizer"),
+        mStatement(aStatement),
+        mConnection(aConnection) {}
+
+  NS_IMETHOD Run() override {
+    if (mStatement->mAsyncStatement) {
+      sqlite3_finalize(mStatement->mAsyncStatement);
+      mStatement->mAsyncStatement = nullptr;
+    }
+
+    nsCOMPtr<nsIEventTarget> target(mConnection->eventTargetOpenedOn);
+    NS_ProxyRelease("AsyncStatementFinalizer::mStatement", target,
+                    mStatement.forget());
+    return NS_OK;
+  }
+
+ private:
+  RefPtr<StorageBaseStatementInternal> mStatement;
+  RefPtr<Connection> mConnection;
+};
+
+/**
+ * Finalize a sqlite3_stmt on the background thread for a statement whose
+ * destructor was invoked and the statement was non-null.
+ */
+class LastDitchSqliteStatementFinalizer : public Runnable {
+ public:
+  /**
+   * Event constructor.
+   *
+   * @param aConnection
+   *        Used to keep the connection alive.  If we failed to do this, it
+   *        is possible that the statement going out of scope invoking us
+   *        might have the last reference to the connection and so trigger
+   *        an attempt to close the connection which is doomed to fail
+   *        (because the asynchronous execution event target must exist which
+   *        will trigger the failure case).
+   * @param aStatement
+   *        The sqlite3_stmt to finalize.  This object takes ownership /
+   *        responsibility for the instance and all other references to it
+   *        should be forgotten.
+   */
+  LastDitchSqliteStatementFinalizer(RefPtr<Connection>& aConnection,
+                                    sqlite3_stmt* aStatement)
+      : Runnable("storage::LastDitchSqliteStatementFinalizer"),
+        mConnection(aConnection),
+        mAsyncStatement(aStatement) {
+    MOZ_ASSERT(aConnection, "You must provide a Connection");
+  }
+
+  NS_IMETHOD Run() override {
+    (void)::sqlite3_finalize(mAsyncStatement);
+    mAsyncStatement = nullptr;
+
+    nsCOMPtr<nsIEventTarget> target(mConnection->eventTargetOpenedOn);
+    (void)::NS_ProxyRelease("LastDitchSqliteStatementFinalizer::mConnection",
+                            target, mConnection.forget());
+    return NS_OK;
+  }
+
+ private:
+  RefPtr<Connection> mConnection;
+  sqlite3_stmt* mAsyncStatement;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// StorageBaseStatementInternal
+
+StorageBaseStatementInternal::StorageBaseStatementInternal()
+    : mNativeConnection(nullptr), mAsyncStatement(nullptr) {}
+
+void StorageBaseStatementInternal::asyncFinalize() {
+  nsIEventTarget* target = mDBConnection->getAsyncExecutionTarget();
+  if (target) {
+    // Attempt to finalize asynchronously
+    nsCOMPtr<nsIRunnable> event =
+        new AsyncStatementFinalizer(this, mDBConnection);
+
+    // Dispatch. Note that dispatching can fail, typically if
+    // we have a race condition with asyncClose(). It's ok,
+    // let asyncClose() win.
+    (void)target->Dispatch(event, NS_DISPATCH_NORMAL);
+  }
+  // If we cannot get the background thread,
+  // mozStorageConnection::AsyncClose() has already been called and
+  // the statement either has been or will be cleaned up by
+  // internalClose().
+}
+
+void StorageBaseStatementInternal::destructorAsyncFinalize() {
+  if (!mAsyncStatement) return;
+
+  if (IsOnCurrentSerialEventTarget(mDBConnection->eventTargetOpenedOn)) {
+    // If we are the owning event target (currently that means we're also the
+    // main thread), then we can get the async target and just dispatch to it.
+    nsIEventTarget* target = mDBConnection->getAsyncExecutionTarget();
+    if (target) {
+      nsCOMPtr<nsIRunnable> event =
+          new LastDitchSqliteStatementFinalizer(mDBConnection, mAsyncStatement);
+      (void)target->Dispatch(event, NS_DISPATCH_NORMAL);
+    }
+  } else {
+    // If we're not the owning event target, assume we're the async event
+    // target, and just run the statement.
+    nsCOMPtr<nsIRunnable> event =
+        new LastDitchSqliteStatementFinalizer(mDBConnection, mAsyncStatement);
+    (void)event->Run();
+  }
+
+  // We might not be able to dispatch to the background thread,
+  // presumably because it is being shutdown. Since said shutdown will
+  // finalize the statement, we just need to clean-up around here.
+  mAsyncStatement = nullptr;
+}
+
+NS_IMETHODIMP
+StorageBaseStatementInternal::NewBindingParamsArray(
+    mozIStorageBindingParamsArray** _array) {
+  nsCOMPtr<mozIStorageBindingParamsArray> array = new BindingParamsArray(this);
+  NS_ENSURE_TRUE(array, NS_ERROR_OUT_OF_MEMORY);
+
+  array.forget(_array);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+StorageBaseStatementInternal::ExecuteAsync(
+    mozIStorageStatementCallback* aCallback,
+    mozIStoragePendingStatement** _stmt) {
+  // We used to call Connection::ExecuteAsync but it takes a
+  // mozIStorageBaseStatement signature because it is also a public API.  Since
+  // our 'this' has no static concept of mozIStorageBaseStatement and Connection
+  // would just QI it back across to a StorageBaseStatementInternal and the
+  // actual logic is very simple, we now roll our own.
+  nsTArray<StatementData> stmts(1);
+  StatementData data;
+  nsresult rv = getAsynchronousStatementData(data);
+  NS_ENSURE_SUCCESS(rv, rv);
+  stmts.AppendElement(data);
+
+  // Dispatch to the background
+  return AsyncExecuteStatements::execute(std::move(stmts), mDBConnection,
+                                         mNativeConnection, aCallback, _stmt);
+}
+
+template <typename T>
+void EscapeStringForLIKEInternal(const T& aValue,
+                                 const typename T::char_type aEscapeChar,
+                                 T& aResult) {
+  const typename T::char_type MATCH_ALL('%');
+  const typename T::char_type MATCH_ONE('_');
+
+  aResult.Truncate(0);
+
+  for (uint32_t i = 0; i < aValue.Length(); i++) {
+    if (aValue[i] == aEscapeChar || aValue[i] == MATCH_ALL ||
+        aValue[i] == MATCH_ONE) {
+      aResult += aEscapeChar;
+    }
+    aResult += aValue[i];
+  }
+}
+
+NS_IMETHODIMP
+StorageBaseStatementInternal::EscapeStringForLIKE(const nsAString& aValue,
+                                                  const char16_t aEscapeChar,
+                                                  nsAString& _escapedString) {
+  EscapeStringForLIKEInternal(aValue, aEscapeChar, _escapedString);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+StorageBaseStatementInternal::EscapeUTF8StringForLIKE(
+    const nsACString& aValue, const char aEscapeChar,
+    nsACString& _escapedString) {
+  EscapeStringForLIKEInternal(aValue, aEscapeChar, _escapedString);
+
+  return NS_OK;
+}
+
+}  // namespace storage
+}  // namespace mozilla
diff --git a/storage/StorageBaseStatementInternal.h b/storage/StorageBaseStatementInternal.h
new file mode 100644
index 0000000000..685f0f79d0
--- /dev/null
+++ b/storage/StorageBaseStatementInternal.h
@@ -0,0 +1,297 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 sts=2 expandtab
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_storage_StorageBaseStatementInternal_h_
+#define mozilla_storage_StorageBaseStatementInternal_h_
+
+#include "nsISupports.h"
+#include "nsCOMPtr.h"
+#include "mozStorageHelper.h"
+
+struct sqlite3;
+struct sqlite3_stmt;
+class mozIStorageBindingParamsArray;
+class mozIStorageBindingParams;
+class mozIStorageStatementCallback;
+class mozIStoragePendingStatement;
+
+namespace mozilla {
+namespace storage {
+
+#define STORAGEBASESTATEMENTINTERNAL_IID             \
+  {                                                  \
+    0xd18856c9, 0xbf07, 0x4ae2, {                    \
+      0x94, 0x5b, 0x1a, 0xdd, 0x49, 0x19, 0x55, 0x2a \
+    }                                                \
+  }
+
+class Connection;
+class StatementData;
+
+class AsyncStatementFinalizer;
+
+/**
+ * Implementation-only interface and shared logix mix-in corresponding to
+ * mozIStorageBaseStatement.  Both Statement and AsyncStatement inherit from
+ * this. The interface aspect makes them look the same to implementation innards
+ * that aren't publicly accessible.  The mix-in avoids code duplication in
+ * common implementations of mozIStorageBaseStatement, albeit with some minor
+ * performance/space overhead because we have to use defines to officially
+ * implement the methods on Statement/AsyncStatement (and proxy to this base
+ * class.)
+ */
+class StorageBaseStatementInternal : public nsISupports {
+ public:
+  NS_DECLARE_STATIC_IID_ACCESSOR(STORAGEBASESTATEMENTINTERNAL_IID)
+
+  /**
+   * @return the connection that this statement belongs to.
+   */
+  Connection* getOwner() { return mDBConnection; }
+
+  /**
+   * Return the asynchronous statement, creating it if required.
+   *
+   * This is for use by the asynchronous execution code for StatementData
+   * created by AsyncStatements.  Statement internally uses this method to
+   * prepopulate StatementData with the sqlite3_stmt.
+   *
+   * @param[out] stmt
+   *             The sqlite3_stmt for asynchronous use.
+   * @return The SQLite result code for creating the statement if created,
+   *         SQLITE_OK if creation was not required.
+   */
+  virtual int getAsyncStatement(sqlite3_stmt** _stmt) = 0;
+
+  /**
+   * Obtains the StatementData needed for asynchronous execution.
+   *
+   * This is for use by Connection to retrieve StatementData from statements
+   * when executeAsync is invoked.
+   *
+   * @param[out] _data
+   *             A reference to a StatementData object that will be populated
+   *             upon successful execution of this method.
+   * @return NS_OK if we were able to assemble the data, failure otherwise.
+   */
+  virtual nsresult getAsynchronousStatementData(StatementData& _data) = 0;
+
+  /**
+   * Construct a new BindingParams to be owned by the provided binding params
+   * array.  This method exists so that BindingParamsArray does not need
+   * factory logic to determine what type of BindingParams to instantiate.
+   *
+   * @param aOwner
+   *        The binding params array to own the newly created binding params.
+   * @return The new mozIStorageBindingParams instance appropriate to the
+   *         underlying statement type.
+   */
+  virtual already_AddRefed<mozIStorageBindingParams> newBindingParams(
+      mozIStorageBindingParamsArray* aOwner) = 0;
+
+ protected:  // mix-in bits are protected
+  StorageBaseStatementInternal();
+
+  RefPtr<Connection> mDBConnection;
+  sqlite3* mNativeConnection;
+
+  /**
+   * Our asynchronous statement.
+   *
+   * For Statement this is populated by the first invocation to
+   * getAsyncStatement.
+   *
+   * For AsyncStatement, this is null at creation time and initialized by the
+   * async thread when it calls getAsyncStatement the first time the statement
+   * is executed.  (Or in the event of badly formed SQL, every time.)
+   */
+  sqlite3_stmt* mAsyncStatement;
+
+  /**
+   * Initiate asynchronous finalization by dispatching an event to the
+   * asynchronous thread to finalize mAsyncStatement.  This acquires a reference
+   * to this statement and proxies it back to the connection's owning thread
+   * for release purposes.
+   *
+   * In the event the asynchronous thread is already gone or we otherwise fail
+   * to dispatch an event to it we failover to invoking internalAsyncFinalize
+   * directly.  (That's what the asynchronous finalizer would have called.)
+   *
+   * @note You must not call this method from your destructor because its
+   *       operation assumes we are still alive.  Call internalAsyncFinalize
+   *       directly in that case.
+   */
+  void asyncFinalize();
+
+  /**
+   * Cleanup the async sqlite3_stmt stored in mAsyncStatement if it exists by
+   * attempting to dispatch to the asynchronous thread if available, finalizing
+   * on this thread if it is not.
+   *
+   * @note Call this from your destructor, call asyncFinalize otherwise.
+   */
+  void destructorAsyncFinalize();
+
+  NS_IMETHOD NewBindingParamsArray(mozIStorageBindingParamsArray** _array);
+  NS_IMETHOD ExecuteAsync(mozIStorageStatementCallback* aCallback,
+                          mozIStoragePendingStatement** _stmt);
+  NS_IMETHOD EscapeStringForLIKE(const nsAString& aValue, char16_t aEscapeChar,
+                                 nsAString& _escapedString);
+  NS_IMETHOD EscapeUTF8StringForLIKE(const nsACString& aValue, char aEscapeChar,
+                                     nsACString& _escapedString);
+
+  // Needs access to internalAsyncFinalize
+  friend class AsyncStatementFinalizer;
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(StorageBaseStatementInternal,
+                              STORAGEBASESTATEMENTINTERNAL_IID)
+
+#define NS_DECL_STORAGEBASESTATEMENTINTERNAL                           \
+  virtual Connection* getOwner();                                      \
+  virtual int getAsyncStatement(sqlite3_stmt** _stmt) override;        \
+  virtual nsresult getAsynchronousStatementData(StatementData& _data)  \
+      override;                                                        \
+  virtual already_AddRefed<mozIStorageBindingParams> newBindingParams( \
+      mozIStorageBindingParamsArray* aOwner) override;
+
+/**
+ * Helper macro to implement the proxying implementations.  Because we are
+ * implementing methods that are part of mozIStorageBaseStatement and the
+ * implementation classes already use NS_DECL_MOZISTORAGEBASESTATEMENT we don't
+ * need to provide declaration support.
+ */
+#define MIX_IMPL(_class, _optionalGuard, _method, _declArgs, _invokeArgs)    \
+  NS_IMETHODIMP _class::_method _declArgs {                                  \
+    _optionalGuard return StorageBaseStatementInternal::_method _invokeArgs; \
+  }
+
+/**
+ * Define proxying implementation for the given _class.  If a state invariant
+ * needs to be checked and an early return possibly performed, pass the clause
+ * to use as _optionalGuard.
+ */
+#define MIXIN_IMPL_STORAGEBASESTATEMENTINTERNAL(_class, _optionalGuard) \
+  MIX_IMPL(_class, _optionalGuard, NewBindingParamsArray,               \
+           (mozIStorageBindingParamsArray * *_array), (_array))         \
+  MIX_IMPL(_class, _optionalGuard, ExecuteAsync,                        \
+           (mozIStorageStatementCallback * aCallback,                   \
+            mozIStoragePendingStatement * *_stmt),                      \
+           (aCallback, _stmt))                                          \
+  MIX_IMPL(_class, _optionalGuard, EscapeStringForLIKE,                 \
+           (const nsAString& aValue, char16_t aEscapeChar,              \
+            nsAString& _escapedString),                                 \
+           (aValue, aEscapeChar, _escapedString))                       \
+  MIX_IMPL(_class, _optionalGuard, EscapeUTF8StringForLIKE,             \
+           (const nsACString& aValue, char aEscapeChar,                 \
+            nsACString& _escapedString),                                \
+           (aValue, aEscapeChar, _escapedString))
+
+/**
+ * Name-building helper for BIND_GEN_IMPL.
+ */
+#define BIND_NAME_CONCAT(_nameBit, _concatBit) Bind##_nameBit##_concatBit
+
+/**
+ * We have type-specific convenience methods for C++ implementations in
+ * two different forms; by index and by name.  The following macro allows
+ * us to avoid having to define repetitive things by hand.
+ *
+ * Because of limitations of macros and our desire to avoid requiring special
+ * permutations for the null and blob cases (whose argument count varies),
+ * we require that the argument declarations and corresponding invocation
+ * usages are passed in.
+ *
+ * @param _class
+ *        The class name.
+ * @param _guard
+ *        The guard clause to inject.
+ * @param _declName
+ *        The argument list (with parens) for the ByName variants.
+ * @param _declIndex
+ *        The argument list (with parens) for the ByIndex variants.
+ * @param _invArgs
+ *        The invocation argumment list.
+ */
+#define BIND_GEN_IMPL(_class, _guard, _name, _declName, _declIndex, _invArgs) \
+  NS_IMETHODIMP _class::BIND_NAME_CONCAT(_name, ByName) _declName {           \
+    _guard mozIStorageBindingParams* params = getParams();                    \
+    NS_ENSURE_TRUE(params, NS_ERROR_OUT_OF_MEMORY);                           \
+    return params->BIND_NAME_CONCAT(_name, ByName) _invArgs;                  \
+  }                                                                           \
+  NS_IMETHODIMP _class::BIND_NAME_CONCAT(_name, ByIndex) _declIndex {         \
+    _guard mozIStorageBindingParams* params = getParams();                    \
+    NS_ENSURE_TRUE(params, NS_ERROR_OUT_OF_MEMORY);                           \
+    return params->BIND_NAME_CONCAT(_name, ByIndex) _invArgs;                 \
+  }
+
+/**
+ * Implement BindByName/BindByIndex for the given class.
+ *
+ * @param _class The class name.
+ * @param _optionalGuard The guard clause to inject.
+ */
+#define BIND_BASE_IMPLS(_class, _optionalGuard)                            \
+  NS_IMETHODIMP _class::BindByName(const nsACString& aName,                \
+                                   nsIVariant* aValue) {                   \
+    _optionalGuard mozIStorageBindingParams* params = getParams();         \
+    NS_ENSURE_TRUE(params, NS_ERROR_OUT_OF_MEMORY);                        \
+    return params->BindByName(aName, aValue);                              \
+  }                                                                        \
+  NS_IMETHODIMP _class::BindByIndex(uint32_t aIndex, nsIVariant* aValue) { \
+    _optionalGuard mozIStorageBindingParams* params = getParams();         \
+    NS_ENSURE_TRUE(params, NS_ERROR_OUT_OF_MEMORY);                        \
+    return params->BindByIndex(aIndex, aValue);                            \
+  }
+
+/**
+ * Define the various Bind*ByIndex, Bind*ByName stubs that just end up proxying
+ * to the params object.
+ */
+#define BOILERPLATE_BIND_PROXIES(_class, _optionalGuard)                       \
+  BIND_BASE_IMPLS(_class, _optionalGuard)                                      \
+  BIND_GEN_IMPL(_class, _optionalGuard, UTF8String,                            \
+                (const nsACString& aWhere, const nsACString& aValue),          \
+                (uint32_t aWhere, const nsACString& aValue), (aWhere, aValue)) \
+  BIND_GEN_IMPL(_class, _optionalGuard, String,                                \
+                (const nsACString& aWhere, const nsAString& aValue),           \
+                (uint32_t aWhere, const nsAString& aValue), (aWhere, aValue))  \
+  BIND_GEN_IMPL(_class, _optionalGuard, Double,                                \
+                (const nsACString& aWhere, double aValue),                     \
+                (uint32_t aWhere, double aValue), (aWhere, aValue))            \
+  BIND_GEN_IMPL(_class, _optionalGuard, Int32,                                 \
+                (const nsACString& aWhere, int32_t aValue),                    \
+                (uint32_t aWhere, int32_t aValue), (aWhere, aValue))           \
+  BIND_GEN_IMPL(_class, _optionalGuard, Int64,                                 \
+                (const nsACString& aWhere, int64_t aValue),                    \
+                (uint32_t aWhere, int64_t aValue), (aWhere, aValue))           \
+  BIND_GEN_IMPL(_class, _optionalGuard, Null, (const nsACString& aWhere),      \
+                (uint32_t aWhere), (aWhere))                                   \
+  BIND_GEN_IMPL(                                                               \
+      _class, _optionalGuard, Blob,                                            \
+      (const nsACString& aWhere, const uint8_t* aValue, uint32_t aValueSize),  \
+      (uint32_t aWhere, const uint8_t* aValue, uint32_t aValueSize),           \
+      (aWhere, aValue, aValueSize))                                            \
+  BIND_GEN_IMPL(_class, _optionalGuard, BlobArray,                             \
+                (const nsACString& aWhere, const nsTArray<uint8_t>& aValue),   \
+                (uint32_t aWhere, const nsTArray<uint8_t>& aValue),            \
+                (aWhere, aValue))                                              \
+  BIND_GEN_IMPL(_class, _optionalGuard, StringAsBlob,                          \
+                (const nsACString& aWhere, const nsAString& aValue),           \
+                (uint32_t aWhere, const nsAString& aValue), (aWhere, aValue))  \
+  BIND_GEN_IMPL(_class, _optionalGuard, UTF8StringAsBlob,                      \
+                (const nsACString& aWhere, const nsACString& aValue),          \
+                (uint32_t aWhere, const nsACString& aValue), (aWhere, aValue)) \
+  BIND_GEN_IMPL(                                                               \
+      _class, _optionalGuard, AdoptedBlob,                                     \
+      (const nsACString& aWhere, uint8_t* aValue, uint32_t aValueSize),        \
+      (uint32_t aWhere, uint8_t * aValue, uint32_t aValueSize),                \
+      (aWhere, aValue, aValueSize))
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif  // mozilla_storage_StorageBaseStatementInternal_h_
diff --git a/storage/VacuumManager.cpp b/storage/VacuumManager.cpp
new file mode 100644
index 0000000000..63eb0f89b4
--- /dev/null
+++ b/storage/VacuumManager.cpp
@@ -0,0 +1,286 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/DebugOnly.h"
+
+#include "VacuumManager.h"
+
+#include "mozilla/ErrorNames.h"
+#include "mozilla/Services.h"
+#include "mozilla/Preferences.h"
+#include "nsIObserverService.h"
+#include "nsIFile.h"
+#include "nsThreadUtils.h"
+#include "mozilla/Logging.h"
+#include "prtime.h"
+#include "mozilla/StaticPrefs_storage.h"
+
+#include "mozStorageConnection.h"
+#include "mozStoragePrivateHelpers.h"
+#include "mozIStorageStatement.h"
+#include "mozIStorageCompletionCallback.h"
+#include "mozIStorageAsyncStatement.h"
+#include "mozIStoragePendingStatement.h"
+#include "mozIStorageError.h"
+#include "mozStorageHelper.h"
+#include "nsXULAppAPI.h"
+#include "xpcpublic.h"
+
+#define OBSERVER_TOPIC_IDLE_DAILY "idle-daily"
+
+// Used to notify the begin and end of a vacuum operation.
+#define OBSERVER_TOPIC_VACUUM_BEGIN "vacuum-begin"
+#define OBSERVER_TOPIC_VACUUM_END "vacuum-end"
+// This notification is sent only in automation when vacuum for a database is
+// skipped, and can thus be used to verify that.
+#define OBSERVER_TOPIC_VACUUM_SKIP "vacuum-skip"
+
+// This preferences root will contain last vacuum timestamps (in seconds) for
+// each database.  The database filename is used as a key.
+#define PREF_VACUUM_BRANCH "storage.vacuum.last."
+
+// Time between subsequent vacuum calls for a certain database.
+#define VACUUM_INTERVAL_SECONDS (30 * 86400)  // 30 days.
+
+extern mozilla::LazyLogModule gStorageLog;
+
+namespace mozilla::storage {
+
+namespace {
+
+////////////////////////////////////////////////////////////////////////////////
+//// Vacuumer declaration.
+
+class Vacuumer final : public mozIStorageCompletionCallback {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_MOZISTORAGECOMPLETIONCALLBACK
+
+  explicit Vacuumer(mozIStorageVacuumParticipant* aParticipant);
+  bool execute();
+
+ private:
+  nsresult notifyCompletion(bool aSucceeded);
+  ~Vacuumer() = default;
+
+  nsCOMPtr<mozIStorageVacuumParticipant> mParticipant;
+  nsCString mDBFilename;
+  nsCOMPtr<mozIStorageAsyncConnection> mDBConn;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Vacuumer implementation.
+
+NS_IMPL_ISUPPORTS(Vacuumer, mozIStorageCompletionCallback)
+
+Vacuumer::Vacuumer(mozIStorageVacuumParticipant* aParticipant)
+    : mParticipant(aParticipant) {}
+
+bool Vacuumer::execute() {
+  MOZ_ASSERT(NS_IsMainThread(), "Must be running on the main thread!");
+
+  // Get the connection and check its validity.
+  nsresult rv = mParticipant->GetDatabaseConnection(getter_AddRefs(mDBConn));
+  if (NS_FAILED(rv) || !mDBConn) return false;
+
+  nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+
+  bool inAutomation = xpc::IsInAutomation();
+  // Get the database filename.  Last vacuum time is stored under this name
+  // in PREF_VACUUM_BRANCH.
+  nsCOMPtr<nsIFile> databaseFile;
+  mDBConn->GetDatabaseFile(getter_AddRefs(databaseFile));
+  if (!databaseFile) {
+    NS_WARNING("Trying to vacuum a in-memory database!");
+    if (inAutomation && os) {
+      mozilla::Unused << os->NotifyObservers(
+          nullptr, OBSERVER_TOPIC_VACUUM_SKIP, u":memory:");
+    }
+    return false;
+  }
+  nsAutoString databaseFilename;
+  rv = databaseFile->GetLeafName(databaseFilename);
+  NS_ENSURE_SUCCESS(rv, false);
+  CopyUTF16toUTF8(databaseFilename, mDBFilename);
+  MOZ_ASSERT(!mDBFilename.IsEmpty(), "Database filename cannot be empty");
+
+  // Check interval from last vacuum.
+  int32_t now = static_cast<int32_t>(PR_Now() / PR_USEC_PER_SEC);
+  int32_t lastVacuum;
+  nsAutoCString prefName(PREF_VACUUM_BRANCH);
+  prefName += mDBFilename;
+  rv = Preferences::GetInt(prefName.get(), &lastVacuum);
+  if (NS_SUCCEEDED(rv) && (now - lastVacuum) < VACUUM_INTERVAL_SECONDS) {
+    // This database was vacuumed recently, skip it.
+    if (inAutomation && os) {
+      mozilla::Unused << os->NotifyObservers(
+          nullptr, OBSERVER_TOPIC_VACUUM_SKIP,
+          NS_ConvertUTF8toUTF16(mDBFilename).get());
+    }
+    return false;
+  }
+
+  // Notify that we are about to start vacuuming.  The participant can opt-out
+  // if it cannot handle a vacuum at this time, and then we'll move to the next
+  // one.
+  bool vacuumGranted = false;
+  rv = mParticipant->OnBeginVacuum(&vacuumGranted);
+  NS_ENSURE_SUCCESS(rv, false);
+  if (!vacuumGranted) {
+    if (inAutomation && os) {
+      mozilla::Unused << os->NotifyObservers(
+          nullptr, OBSERVER_TOPIC_VACUUM_SKIP,
+          NS_ConvertUTF8toUTF16(mDBFilename).get());
+    }
+    return false;
+  }
+
+  // Ask for the expected page size.  Vacuum can change the page size, unless
+  // the database is using WAL journaling.
+  // TODO Bug 634374: figure out a strategy to fix page size with WAL.
+  int32_t expectedPageSize = 0;
+  rv = mParticipant->GetExpectedDatabasePageSize(&expectedPageSize);
+  if (NS_FAILED(rv) || !Service::pageSizeIsValid(expectedPageSize)) {
+    NS_WARNING("Invalid page size requested for database, won't set it. ");
+    NS_WARNING(mDBFilename.get());
+    expectedPageSize = 0;
+  }
+
+  bool incremental = false;
+  mozilla::Unused << mParticipant->GetUseIncrementalVacuum(&incremental);
+
+  // Notify vacuum is about to start.
+  if (os) {
+    mozilla::Unused << os->NotifyObservers(
+        nullptr, OBSERVER_TOPIC_VACUUM_BEGIN,
+        NS_ConvertUTF8toUTF16(mDBFilename).get());
+  }
+
+  rv = mDBConn->AsyncVacuum(this, incremental, expectedPageSize);
+  if (NS_FAILED(rv)) {
+    // The connection is not ready.
+    mozilla::Unused << Complete(rv, nullptr);
+    return false;
+  }
+
+  return true;
+}
+
+NS_IMETHODIMP
+Vacuumer::Complete(nsresult aStatus, nsISupports* aValue) {
+  if (NS_SUCCEEDED(aStatus)) {
+    // Update last vacuum time.
+    int32_t now = static_cast<int32_t>(PR_Now() / PR_USEC_PER_SEC);
+    MOZ_ASSERT(!mDBFilename.IsEmpty(), "Database filename cannot be empty");
+    nsAutoCString prefName(PREF_VACUUM_BRANCH);
+    prefName += mDBFilename;
+    DebugOnly<nsresult> rv = Preferences::SetInt(prefName.get(), now);
+    MOZ_ASSERT(NS_SUCCEEDED(rv), "Should be able to set a preference");
+    notifyCompletion(true);
+    return NS_OK;
+  }
+
+  nsAutoCString errName;
+  GetErrorName(aStatus, errName);
+  nsCString errMsg = nsPrintfCString(
+      "Vacuum failed on '%s' with error %s - code %" PRIX32, mDBFilename.get(),
+      errName.get(), static_cast<uint32_t>(aStatus));
+  NS_WARNING(errMsg.get());
+  if (MOZ_LOG_TEST(gStorageLog, LogLevel::Error)) {
+    MOZ_LOG(gStorageLog, LogLevel::Error, ("%s", errMsg.get()));
+  }
+
+  notifyCompletion(false);
+  return NS_OK;
+}
+
+nsresult Vacuumer::notifyCompletion(bool aSucceeded) {
+  nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+  if (os) {
+    mozilla::Unused << os->NotifyObservers(
+        nullptr, OBSERVER_TOPIC_VACUUM_END,
+        NS_ConvertUTF8toUTF16(mDBFilename).get());
+  }
+
+  nsresult rv = mParticipant->OnEndVacuum(aSucceeded);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+}  // namespace
+
+////////////////////////////////////////////////////////////////////////////////
+//// VacuumManager
+
+NS_IMPL_ISUPPORTS(VacuumManager, nsIObserver)
+
+VacuumManager* VacuumManager::gVacuumManager = nullptr;
+
+already_AddRefed<VacuumManager> VacuumManager::getSingleton() {
+  // Don't allocate it in the child Process.
+  if (!XRE_IsParentProcess()) {
+    return nullptr;
+  }
+
+  if (!gVacuumManager) {
+    auto manager = MakeRefPtr<VacuumManager>();
+    MOZ_ASSERT(gVacuumManager == manager.get());
+    return manager.forget();
+  }
+  return do_AddRef(gVacuumManager);
+}
+
+VacuumManager::VacuumManager() : mParticipants("vacuum-participant") {
+  MOZ_ASSERT(!gVacuumManager,
+             "Attempting to create two instances of the service!");
+  gVacuumManager = this;
+}
+
+VacuumManager::~VacuumManager() {
+  // Remove the static reference to the service.  Check to make sure its us
+  // in case somebody creates an extra instance of the service.
+  MOZ_ASSERT(gVacuumManager == this,
+             "Deleting a non-singleton instance of the service");
+  if (gVacuumManager == this) {
+    gVacuumManager = nullptr;
+  }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsIObserver
+
+NS_IMETHODIMP
+VacuumManager::Observe(nsISupports* aSubject, const char* aTopic,
+                       const char16_t* aData) {
+  if (strcmp(aTopic, OBSERVER_TOPIC_IDLE_DAILY) == 0) {
+    // Try to run vacuum on all registered entries.  Will stop at the first
+    // successful one.
+    nsCOMArray<mozIStorageVacuumParticipant> entries;
+    mParticipants.GetEntries(entries);
+    // If there are more entries than what a month can contain, we could end up
+    // skipping some, since we run daily.  So we use a starting index.
+    static const char* kPrefName = PREF_VACUUM_BRANCH "index";
+    int32_t startIndex = Preferences::GetInt(kPrefName, 0);
+    if (startIndex >= entries.Count()) {
+      startIndex = 0;
+    }
+    int32_t index;
+    for (index = startIndex; index < entries.Count(); ++index) {
+      RefPtr<Vacuumer> vacuum = new Vacuumer(entries[index]);
+      // Only vacuum one database per day.
+      if (vacuum->execute()) {
+        break;
+      }
+    }
+    DebugOnly<nsresult> rv = Preferences::SetInt(kPrefName, index);
+    MOZ_ASSERT(NS_SUCCEEDED(rv), "Should be able to set a preference");
+  }
+
+  return NS_OK;
+}
+
+}  // namespace mozilla::storage
diff --git a/storage/VacuumManager.h b/storage/VacuumManager.h
new file mode 100644
index 0000000000..0b0dda2de5
--- /dev/null
+++ b/storage/VacuumManager.h
@@ -0,0 +1,43 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_storage_VacuumManager_h__
+#define mozilla_storage_VacuumManager_h__
+
+#include "nsCOMPtr.h"
+#include "nsIObserver.h"
+#include "mozIStorageVacuumParticipant.h"
+#include "nsCategoryCache.h"
+#include "mozilla/Attributes.h"
+
+namespace mozilla {
+namespace storage {
+
+class VacuumManager final : public nsIObserver {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIOBSERVER
+
+  VacuumManager();
+
+  /**
+   * Obtains the VacuumManager object.
+   */
+  static already_AddRefed<VacuumManager> getSingleton();
+
+ private:
+  ~VacuumManager();
+
+  static VacuumManager* gVacuumManager;
+
+  // Cache of components registered in "vacuum-participant" category.
+  nsCategoryCache<mozIStorageVacuumParticipant> mParticipants;
+};
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif
diff --git a/storage/Variant.cpp b/storage/Variant.cpp
new file mode 100644
index 0000000000..61cb5b0676
--- /dev/null
+++ b/storage/Variant.cpp
@@ -0,0 +1,56 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "Variant.h"
+
+#include "nsCOMPtr.h"
+
+extern "C" {
+
+using namespace mozilla::storage;
+
+/**
+ * Return the data type of the given variant.  This method used to be exposed
+ * to XPCOM, but since bug 1507540 it's marked [notxpcom] in the interface
+ * definition, so we need this C function to access it from Rust.
+ */
+uint16_t NS_GetDataType(nsIVariant* aVariant) {
+  return aVariant->GetDataType();
+}
+
+// Convenience functions to create Storage variants from Rust.
+void NS_NewStorageNullVariant(nsIVariant** aVariant) {
+  nsCOMPtr<nsIVariant> variant = new NullVariant();
+  variant.forget(aVariant);
+}
+
+void NS_NewStorageBooleanVariant(bool aValue, nsIVariant** aVariant) {
+  nsCOMPtr<nsIVariant> variant = new BooleanVariant(aValue);
+  variant.forget(aVariant);
+}
+
+void NS_NewStorageIntegerVariant(int64_t aValue, nsIVariant** aVariant) {
+  nsCOMPtr<nsIVariant> variant = new IntegerVariant(aValue);
+  variant.forget(aVariant);
+}
+
+void NS_NewStorageFloatVariant(double aValue, nsIVariant** aVariant) {
+  nsCOMPtr<nsIVariant> variant = new FloatVariant(aValue);
+  variant.forget(aVariant);
+}
+
+void NS_NewStorageTextVariant(const nsAString& aValue, nsIVariant** aVariant) {
+  nsCOMPtr<nsIVariant> variant = new TextVariant(aValue);
+  variant.forget(aVariant);
+}
+
+void NS_NewStorageUTF8TextVariant(const nsACString& aValue,
+                                  nsIVariant** aVariant) {
+  nsCOMPtr<nsIVariant> variant = new UTF8TextVariant(aValue);
+  variant.forget(aVariant);
+}
+
+}  // extern "C"
diff --git a/storage/Variant.h b/storage/Variant.h
new file mode 100644
index 0000000000..420ca94b94
--- /dev/null
+++ b/storage/Variant.h
@@ -0,0 +1,435 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_storage_Variant_h__
+#define mozilla_storage_Variant_h__
+
+#include <utility>
+
+#include "nsIVariant.h"
+#include "nsString.h"
+#include "nsTArray.h"
+
+#define VARIANT_BASE_IID                             \
+  { /* 78888042-0fa3-4f7a-8b19-7996f99bf1aa */       \
+    0x78888042, 0x0fa3, 0x4f7a, {                    \
+      0x8b, 0x19, 0x79, 0x96, 0xf9, 0x9b, 0xf1, 0xaa \
+    }                                                \
+  }
+
+/**
+ * This class is used by the storage module whenever an nsIVariant needs to be
+ * returned.  We provide traits for the basic sqlite types to make use easier.
+ * The following types map to the indicated sqlite type:
+ * int64_t   -> INTEGER (use IntegerVariant)
+ * double    -> FLOAT (use FloatVariant)
+ * nsString  -> TEXT (use TextVariant)
+ * nsCString -> TEXT (use UTF8TextVariant)
+ * uint8_t[] -> BLOB (use BlobVariant)
+ * nullptr   -> NULL (use NullVariant)
+ *
+ * The kvstore component also reuses this class as a common implementation
+ * of a simple threadsafe variant for the storage of primitive values only.
+ * The BooleanVariant type has been introduced for kvstore use cases and should
+ * be enhanced to provide full boolean variant support for mozStorage.
+ *
+ * Bug 1494102 tracks that work.
+ */
+
+namespace mozilla {
+namespace storage {
+
+////////////////////////////////////////////////////////////////////////////////
+//// Base Class
+
+class Variant_base : public nsIVariant {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIVARIANT
+  NS_DECLARE_STATIC_IID_ACCESSOR(VARIANT_BASE_IID)
+
+ protected:
+  virtual ~Variant_base() = default;
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(Variant_base, VARIANT_BASE_IID)
+
+////////////////////////////////////////////////////////////////////////////////
+//// Traits
+
+/**
+ * Generics
+ */
+
+template <typename DataType>
+struct variant_traits {
+  static inline uint16_t type() { return nsIDataType::VTYPE_EMPTY; }
+};
+
+template <typename DataType, bool Adopting = false>
+struct variant_storage_traits {
+  typedef DataType ConstructorType;
+  typedef DataType StorageType;
+  static inline void storage_conversion(const ConstructorType aData,
+                                        StorageType* _storage) {
+    *_storage = aData;
+  }
+
+  static inline void destroy(const StorageType& _storage) {}
+};
+
+#define NO_CONVERSION return NS_ERROR_CANNOT_CONVERT_DATA;
+
+template <typename DataType, bool Adopting = false>
+struct variant_boolean_traits {
+  typedef typename variant_storage_traits<DataType, Adopting>::StorageType
+      StorageType;
+  static inline nsresult asBool(const StorageType&, bool*) { NO_CONVERSION }
+};
+
+template <typename DataType, bool Adopting = false>
+struct variant_integer_traits {
+  typedef typename variant_storage_traits<DataType, Adopting>::StorageType
+      StorageType;
+  static inline nsresult asInt32(const StorageType&, int32_t*) { NO_CONVERSION }
+  static inline nsresult asInt64(const StorageType&, int64_t*) { NO_CONVERSION }
+};
+
+template <typename DataType, bool Adopting = false>
+struct variant_float_traits {
+  typedef typename variant_storage_traits<DataType, Adopting>::StorageType
+      StorageType;
+  static inline nsresult asDouble(const StorageType&, double*) { NO_CONVERSION }
+};
+
+template <typename DataType, bool Adopting = false>
+struct variant_text_traits {
+  typedef typename variant_storage_traits<DataType, Adopting>::StorageType
+      StorageType;
+  static inline nsresult asUTF8String(const StorageType&, nsACString&) {
+    NO_CONVERSION
+  }
+  static inline nsresult asString(const StorageType&, nsAString&) {
+    NO_CONVERSION
+  }
+};
+
+template <typename DataType, bool Adopting = false>
+struct variant_blob_traits {
+  typedef typename variant_storage_traits<DataType, Adopting>::StorageType
+      StorageType;
+  static inline nsresult asArray(const StorageType&, uint16_t*, uint32_t*,
+                                 void**) {
+    NO_CONVERSION
+  }
+};
+
+#undef NO_CONVERSION
+
+/**
+ * BOOLEAN type
+ */
+
+template <>
+struct variant_traits<bool> {
+  static inline uint16_t type() { return nsIDataType::VTYPE_BOOL; }
+};
+template <>
+struct variant_boolean_traits<bool> {
+  static inline nsresult asBool(bool aValue, bool* _result) {
+    *_result = aValue;
+    return NS_OK;
+  }
+
+  // NB: It might be worth also providing conversions to int types.
+
+  // NB: It'd be nice to implement asBool conversions for 0 and 1, too.
+  // That would let us clean up some conversions in Places, such as:
+  // https://searchfox.org/mozilla-central/rev/0640ea80fbc8d48f8b197cd363e2535c95a15eb3/toolkit/components/places/SQLFunctions.cpp#564-565
+  // https://searchfox.org/mozilla-central/rev/0640ea80fbc8d48f8b197cd363e2535c95a15eb3/toolkit/components/places/SQLFunctions.cpp#1057
+  // https://searchfox.org/mozilla-central/rev/0640ea80fbc8d48f8b197cd363e2535c95a15eb3/toolkit/components/places/nsNavHistory.cpp#3189
+};
+
+/**
+ * INTEGER types
+ */
+
+template <>
+struct variant_traits<int64_t> {
+  static inline uint16_t type() { return nsIDataType::VTYPE_INT64; }
+};
+template <>
+struct variant_integer_traits<int64_t> {
+  static inline nsresult asInt32(int64_t aValue, int32_t* _result) {
+    if (aValue > INT32_MAX || aValue < INT32_MIN)
+      return NS_ERROR_CANNOT_CONVERT_DATA;
+
+    *_result = static_cast<int32_t>(aValue);
+    return NS_OK;
+  }
+  static inline nsresult asInt64(int64_t aValue, int64_t* _result) {
+    *_result = aValue;
+    return NS_OK;
+  }
+};
+// xpcvariant just calls get double for integers...
+template <>
+struct variant_float_traits<int64_t> {
+  static inline nsresult asDouble(int64_t aValue, double* _result) {
+    *_result = double(aValue);
+    return NS_OK;
+  }
+};
+
+/**
+ * FLOAT types
+ */
+
+template <>
+struct variant_traits<double> {
+  static inline uint16_t type() { return nsIDataType::VTYPE_DOUBLE; }
+};
+template <>
+struct variant_float_traits<double> {
+  static inline nsresult asDouble(double aValue, double* _result) {
+    *_result = aValue;
+    return NS_OK;
+  }
+};
+
+/**
+ * TEXT types
+ */
+
+template <>
+struct variant_traits<nsString> {
+  static inline uint16_t type() { return nsIDataType::VTYPE_ASTRING; }
+};
+template <>
+struct variant_storage_traits<nsString> {
+  typedef const nsAString& ConstructorType;
+  typedef nsString StorageType;
+  static inline void storage_conversion(ConstructorType aText,
+                                        StorageType* _outData) {
+    *_outData = aText;
+  }
+  static inline void destroy(const StorageType& _outData) {}
+};
+template <>
+struct variant_text_traits<nsString> {
+  static inline nsresult asUTF8String(const nsString& aValue,
+                                      nsACString& _result) {
+    CopyUTF16toUTF8(aValue, _result);
+    return NS_OK;
+  }
+  static inline nsresult asString(const nsString& aValue, nsAString& _result) {
+    _result = aValue;
+    return NS_OK;
+  }
+};
+
+template <>
+struct variant_traits<nsCString> {
+  static inline uint16_t type() { return nsIDataType::VTYPE_UTF8STRING; }
+};
+template <>
+struct variant_storage_traits<nsCString> {
+  typedef const nsACString& ConstructorType;
+  typedef nsCString StorageType;
+  static inline void storage_conversion(ConstructorType aText,
+                                        StorageType* _outData) {
+    *_outData = aText;
+  }
+  static inline void destroy(const StorageType& aData) {}
+};
+template <>
+struct variant_text_traits<nsCString> {
+  static inline nsresult asUTF8String(const nsCString& aValue,
+                                      nsACString& _result) {
+    _result = aValue;
+    return NS_OK;
+  }
+  static inline nsresult asString(const nsCString& aValue, nsAString& _result) {
+    CopyUTF8toUTF16(aValue, _result);
+    return NS_OK;
+  }
+};
+
+/**
+ * BLOB types
+ */
+
+template <>
+struct variant_traits<uint8_t[]> {
+  static inline uint16_t type() { return nsIDataType::VTYPE_ARRAY; }
+};
+template <>
+struct variant_storage_traits<uint8_t[], false> {
+  typedef std::pair<const void*, int> ConstructorType;
+  typedef FallibleTArray<uint8_t> StorageType;
+  static inline void storage_conversion(ConstructorType aBlob,
+                                        StorageType* _outData) {
+    _outData->Clear();
+    (void)_outData->AppendElements(static_cast<const uint8_t*>(aBlob.first),
+                                   aBlob.second, fallible);
+  }
+  static inline void destroy(const StorageType& _outData) {}
+};
+template <>
+struct variant_storage_traits<uint8_t[], true> {
+  typedef std::pair<uint8_t*, int> ConstructorType;
+  typedef std::pair<uint8_t*, int> StorageType;
+  static inline void storage_conversion(ConstructorType aBlob,
+                                        StorageType* _outData) {
+    *_outData = aBlob;
+  }
+  static inline void destroy(StorageType& aData) {
+    if (aData.first) {
+      free(aData.first);
+      aData.first = nullptr;
+    }
+  }
+};
+template <>
+struct variant_blob_traits<uint8_t[], false> {
+  static inline nsresult asArray(FallibleTArray<uint8_t>& aData,
+                                 uint16_t* _type, uint32_t* _size,
+                                 void** _result) {
+    // For empty blobs, we return nullptr.
+    if (aData.Length() == 0) {
+      *_result = nullptr;
+      *_type = nsIDataType::VTYPE_UINT8;
+      *_size = 0;
+      return NS_OK;
+    }
+
+    // Otherwise, we copy the array.
+    *_result = moz_xmemdup(aData.Elements(), aData.Length() * sizeof(uint8_t));
+
+    // Set type and size
+    *_type = nsIDataType::VTYPE_UINT8;
+    *_size = aData.Length();
+    return NS_OK;
+  }
+};
+
+template <>
+struct variant_blob_traits<uint8_t[], true> {
+  static inline nsresult asArray(std::pair<uint8_t*, int>& aData,
+                                 uint16_t* _type, uint32_t* _size,
+                                 void** _result) {
+    // For empty blobs, we return nullptr.
+    if (aData.second == 0) {
+      *_result = nullptr;
+      *_type = nsIDataType::VTYPE_UINT8;
+      *_size = 0;
+      return NS_OK;
+    }
+
+    // Otherwise, transfer the data out.
+    *_result = aData.first;
+    aData.first = nullptr;
+    MOZ_ASSERT(*_result);  // We asked for it twice, better not use adopting!
+
+    // Set type and size
+    *_type = nsIDataType::VTYPE_UINT8;
+    *_size = aData.second;
+    return NS_OK;
+  }
+};
+
+/**
+ * nullptr type
+ */
+
+class NullVariant : public Variant_base {
+ public:
+  uint16_t GetDataType() override { return nsIDataType::VTYPE_EMPTY; }
+
+  NS_IMETHOD GetAsAUTF8String(nsACString& _str) override {
+    // Return a void string.
+    _str.SetIsVoid(true);
+    return NS_OK;
+  }
+
+  NS_IMETHOD GetAsAString(nsAString& _str) override {
+    // Return a void string.
+    _str.SetIsVoid(true);
+    return NS_OK;
+  }
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Template Implementation
+
+template <typename DataType, bool Adopting = false>
+class Variant final : public Variant_base {
+  ~Variant() { variant_storage_traits<DataType, Adopting>::destroy(mData); }
+
+ public:
+  explicit Variant(
+      const typename variant_storage_traits<DataType, Adopting>::ConstructorType
+          aData) {
+    variant_storage_traits<DataType, Adopting>::storage_conversion(aData,
+                                                                   &mData);
+  }
+
+  uint16_t GetDataType() override { return variant_traits<DataType>::type(); }
+
+  NS_IMETHOD GetAsBool(bool* _boolean) override {
+    return variant_boolean_traits<DataType, Adopting>::asBool(mData, _boolean);
+  }
+
+  NS_IMETHOD GetAsInt32(int32_t* _integer) override {
+    return variant_integer_traits<DataType, Adopting>::asInt32(mData, _integer);
+  }
+
+  NS_IMETHOD GetAsInt64(int64_t* _integer) override {
+    return variant_integer_traits<DataType, Adopting>::asInt64(mData, _integer);
+  }
+
+  NS_IMETHOD GetAsDouble(double* _double) override {
+    return variant_float_traits<DataType, Adopting>::asDouble(mData, _double);
+  }
+
+  NS_IMETHOD GetAsAUTF8String(nsACString& _str) override {
+    return variant_text_traits<DataType, Adopting>::asUTF8String(mData, _str);
+  }
+
+  NS_IMETHOD GetAsAString(nsAString& _str) override {
+    return variant_text_traits<DataType, Adopting>::asString(mData, _str);
+  }
+
+  NS_IMETHOD GetAsArray(uint16_t* _type, nsIID*, uint32_t* _size,
+                        void** _data) override {
+    return variant_blob_traits<DataType, Adopting>::asArray(mData, _type, _size,
+                                                            _data);
+  }
+
+ private:
+  typename variant_storage_traits<DataType, Adopting>::StorageType mData;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Handy typedefs!  Use these for the right mapping.
+
+// Currently, BooleanVariant is only useful for kvstore.
+// Bug 1494102 tracks implementing full boolean variant support for mozStorage.
+typedef Variant<bool> BooleanVariant;
+
+typedef Variant<int64_t> IntegerVariant;
+typedef Variant<double> FloatVariant;
+typedef Variant<nsString> TextVariant;
+typedef Variant<nsCString> UTF8TextVariant;
+typedef Variant<uint8_t[], false> BlobVariant;
+typedef Variant<uint8_t[], true> AdoptedBlobVariant;
+
+}  // namespace storage
+}  // namespace mozilla
+
+#include "Variant_inl.h"
+
+#endif  // mozilla_storage_Variant_h__
diff --git a/storage/Variant_inl.h b/storage/Variant_inl.h
new file mode 100644
index 0000000000..2238c5f959
--- /dev/null
+++ b/storage/Variant_inl.h
@@ -0,0 +1,136 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Note: This file is included by Variant.h.
+ */
+
+#ifndef mozilla_storage_Variant_h__
+#  error "Do not include this file directly!"
+#endif
+
+#include "js/RootingAPI.h"
+#include "js/Value.h"
+
+namespace mozilla {
+namespace storage {
+
+////////////////////////////////////////////////////////////////////////////////
+//// Variant_base
+
+inline NS_IMPL_ADDREF(Variant_base) inline NS_IMPL_RELEASE(
+    Variant_base) inline NS_IMPL_QUERY_INTERFACE(Variant_base, nsIVariant)
+
+    ////////////////////////////////////////////////////////////////////////////////
+    //// nsIVariant
+
+    inline uint16_t Variant_base::GetDataType() {
+  return nsIDataType::VTYPE_VOID;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsInt32(int32_t*) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsInt64(int64_t*) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsDouble(double*) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsAUTF8String(nsACString&) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsAString(nsAString&) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsArray(uint16_t*, nsIID*, uint32_t*,
+                                              void**) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsInt8(uint8_t*) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsInt16(int16_t*) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsUint8(uint8_t*) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsUint16(uint16_t*) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsUint32(uint32_t*) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsUint64(uint64_t*) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsFloat(float*) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsBool(bool*) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsChar(char*) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsWChar(char16_t*) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsID(nsID*) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsString(char**) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsWString(char16_t**) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsISupports(nsISupports**) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsInterface(nsIID**, void**) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsACString(nsACString&) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsStringWithSize(uint32_t*, char**) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsWStringWithSize(uint32_t*, char16_t**) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+inline NS_IMETHODIMP Variant_base::GetAsJSVal(JS::MutableHandle<JS::Value>) {
+  return NS_ERROR_CANNOT_CONVERT_DATA;
+}
+
+}  // namespace storage
+}  // namespace mozilla
diff --git a/storage/build/components.conf b/storage/build/components.conf
new file mode 100644
index 0000000000..5953e85927
--- /dev/null
+++ b/storage/build/components.conf
@@ -0,0 +1,27 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+Classes = [
+    {
+        'js_name': 'storage',
+        'cid': '{bbbb1d61-438f-4436-92ed-8308e5830fb0}',
+        'contract_ids': ['@mozilla.org/storage/service;1'],
+        'interfaces': ['mozIStorageService'],
+        'singleton': True,
+        'type': 'mozilla::storage::Service',
+        'headers': ['/storage/mozStorageService.h'],
+        'constructor': 'mozilla::storage::Service::getSingleton',
+    },
+    {
+        'cid': '{3b667ee0-d2da-4ccc-9c3d-95f2ca6a8b4c}',
+        'contract_ids': ['@mozilla.org/storage/vacuum;1'],
+        'singleton': True,
+        'type': 'mozilla::storage::VacuumManager',
+        'headers': ['/storage/VacuumManager.h'],
+        'constructor': 'mozilla::storage::VacuumManager::getSingleton',
+        'categories': {'idle-daily': 'MozStorage Vacuum Manager'},
+    },
+]
diff --git a/storage/build/moz.build b/storage/build/moz.build
new file mode 100644
index 0000000000..0af582bb73
--- /dev/null
+++ b/storage/build/moz.build
@@ -0,0 +1,17 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+EXPORTS += [
+    "mozStorageCID.h",
+]
+
+XPCOM_MANIFESTS += [
+    "components.conf",
+]
+
+FINAL_LIBRARY = "xul"
+
+CXXFLAGS += CONFIG["SQLITE_CFLAGS"]
diff --git a/storage/build/mozStorageCID.h b/storage/build/mozStorageCID.h
new file mode 100644
index 0000000000..64f0b6709b
--- /dev/null
+++ b/storage/build/mozStorageCID.h
@@ -0,0 +1,43 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef MOZSTORAGECID_H
+#define MOZSTORAGECID_H
+
+#define MOZ_STORAGE_CONTRACTID_PREFIX "@mozilla.org/storage"
+
+/* b71a1f84-3a70-4d37-a348-f1ba0e27eead */
+#define MOZ_STORAGE_CONNECTION_CID                   \
+  {                                                  \
+    0xb71a1f84, 0x3a70, 0x4d37, {                    \
+      0xa3, 0x48, 0xf1, 0xba, 0x0e, 0x27, 0xee, 0xad \
+    }                                                \
+  }
+
+#define MOZ_STORAGE_CONNECTION_CONTRACTID \
+  MOZ_STORAGE_CONTRACTID_PREFIX "/connection;1"
+
+/* bbbb1d61-438f-4436-92ed-8308e5830fb0 */
+#define MOZ_STORAGE_SERVICE_CID                      \
+  {                                                  \
+    0xbbbb1d61, 0x438f, 0x4436, {                    \
+      0x92, 0xed, 0x83, 0x08, 0xe5, 0x83, 0x0f, 0xb0 \
+    }                                                \
+  }
+
+#define MOZ_STORAGE_SERVICE_CONTRACTID \
+  MOZ_STORAGE_CONTRACTID_PREFIX "/service;1"
+
+/* 3b667ee0-d2da-4ccc-9c3d-95f2ca6a8b4c */
+#define VACUUMMANAGER_CID                            \
+  {                                                  \
+    0x3b667ee0, 0xd2da, 0x4ccc, {                    \
+      0x9c, 0x3d, 0x95, 0xf2, 0xca, 0x6a, 0x8b, 0x4c \
+    }                                                \
+  }
+
+#define VACUUMMANAGER_CONTRACTID MOZ_STORAGE_CONTRACTID_PREFIX "/vacuum;1"
+
+#endif /* MOZSTORAGECID_H */
diff --git a/storage/moz.build b/storage/moz.build
new file mode 100644
index 0000000000..3dc1cd4bf7
--- /dev/null
+++ b/storage/moz.build
@@ -0,0 +1,112 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+with Files("**"):
+    BUG_COMPONENT = ("Toolkit", "Storage")
+
+DIRS += ["build"]
+
+TEST_DIRS += ["test"]
+
+XPIDL_SOURCES += [
+    "mozIStorageAsyncConnection.idl",
+    "mozIStorageAsyncStatement.idl",
+    "mozIStorageBaseStatement.idl",
+    "mozIStorageBindingParams.idl",
+    "mozIStorageBindingParamsArray.idl",
+    "mozIStorageCompletionCallback.idl",
+    "mozIStorageConnection.idl",
+    "mozIStorageError.idl",
+    "mozIStorageFunction.idl",
+    "mozIStoragePendingStatement.idl",
+    "mozIStorageProgressHandler.idl",
+    "mozIStorageResultSet.idl",
+    "mozIStorageRow.idl",
+    "mozIStorageService.idl",
+    "mozIStorageStatement.idl",
+    "mozIStorageStatementCallback.idl",
+    "mozIStorageVacuumParticipant.idl",
+    "mozIStorageValueArray.idl",
+]
+
+XPIDL_MODULE = "storage"
+
+EXPORTS += [
+    "mozStorageHelper.h",
+]
+
+EXPORTS.mozilla += [
+    "storage.h",
+]
+
+# NOTE When adding something to this list, you probably need to add it to the
+#      storage.h file too.
+EXPORTS.mozilla.storage += [
+    "mozStorageAsyncStatementParams.h",
+    "mozStorageStatementParams.h",
+    "mozStorageStatementRow.h",
+    "SQLiteMutex.h",
+    "StatementCache.h",
+    "Variant.h",
+    "Variant_inl.h",
+]
+# SEE ABOVE NOTE!
+
+UNIFIED_SOURCES += [
+    "BaseVFS.cpp",
+    "FileSystemModule.cpp",
+    "mozStorageArgValueArray.cpp",
+    "mozStorageAsyncStatement.cpp",
+    "mozStorageAsyncStatementExecution.cpp",
+    "mozStorageAsyncStatementJSHelper.cpp",
+    "mozStorageAsyncStatementParams.cpp",
+    "mozStorageBindingParamsArray.cpp",
+    "mozStorageError.cpp",
+    "mozStoragePrivateHelpers.cpp",
+    "mozStorageResultSet.cpp",
+    "mozStorageRow.cpp",
+    "mozStorageService.cpp",
+    "mozStorageSQLFunctions.cpp",
+    "mozStorageStatement.cpp",
+    "mozStorageStatementJSHelper.cpp",
+    "mozStorageStatementParams.cpp",
+    "mozStorageStatementRow.cpp",
+    "ObfuscatingVFS.cpp",
+    "QuotaVFS.cpp",
+    "ReadOnlyNoLockVFS.cpp",
+    "SQLCollations.cpp",
+    "StorageBaseStatementInternal.cpp",
+    "VacuumManager.cpp",
+    "Variant.cpp",
+]
+
+# These files need to be built separately because they #include variantToSQLiteT_impl.h.
+SOURCES += [
+    "mozStorageBindingParams.cpp",
+    "mozStorageConnection.cpp",
+]
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+FINAL_LIBRARY = "xul"
+
+# Thunderbird needs the 2-argument version of fts3_tokenizer()
+if CONFIG["MOZ_THUNDERBIRD"] or CONFIG["MOZ_SUITE"]:
+    DEFINES["MOZ_SQLITE_FTS3_TOKENIZER"] = 1
+
+# Disable auxiliary files persistence if requested.
+if not CONFIG["MOZ_AVOID_DISK_REMNANT_ON_CLOSE"]:
+    DEFINES["MOZ_SQLITE_PERSIST_AUXILIARY_FILES"] = 1
+
+LOCAL_INCLUDES += [
+    "/dom/base",
+    "/third_party/sqlite3/src",
+]
+
+if CONFIG["MOZ_FOLD_LIBS"]:
+    DEFINES["MOZ_FOLD_LIBS"] = True
+
+CXXFLAGS += CONFIG["SQLITE_CFLAGS"]
diff --git a/storage/mozIStorageAsyncConnection.idl b/storage/mozIStorageAsyncConnection.idl
new file mode 100644
index 0000000000..3105750773
--- /dev/null
+++ b/storage/mozIStorageAsyncConnection.idl
@@ -0,0 +1,405 @@
+/* -*- Mode: idl; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface mozIStorageCompletionCallback;
+interface mozIStorageFunction;
+interface mozIStorageProgressHandler;
+interface mozIStorageBaseStatement;
+interface mozIStorageStatement;
+interface mozIStorageAsyncStatement;
+interface mozIStorageStatementCallback;
+interface mozIStoragePendingStatement;
+interface nsIFile;
+
+/**
+ * mozIStorageAsyncConnection represents an asynchronous database
+ * connection attached to a specific file or to an in-memory data
+ * storage.  It is the primary interface for interacting with a
+ * database from the main thread, including creating prepared
+ * statements, executing SQL, and examining database errors.
+ */
+[scriptable, uuid(8bfd34d5-4ddf-4e4b-89dd-9b14f33534c6)]
+interface mozIStorageAsyncConnection : nsISupports {
+  /**
+   * Transaction behavior constants.
+   */
+  const int32_t TRANSACTION_DEFAULT = -1;
+  const int32_t TRANSACTION_DEFERRED = 0;
+  const int32_t TRANSACTION_IMMEDIATE = 1;
+  const int32_t TRANSACTION_EXCLUSIVE = 2;
+
+  /**
+   * The default behavior for all transactions run on this connection. Defaults
+   * to `TRANSACTION_DEFERRED`, and can be overridden for individual
+   * transactions.
+   */
+  attribute int32_t defaultTransactionType;
+
+  /**
+   * The maximum number of bound parameters for statements executed on this
+   * connection. If your statement has more params than this limit, you'll
+   * need to chunk them into multiple statements. See `PlacesUtils.chunkArray`
+   * and its callers in Places for examples of how to do this, or read on for
+   * an overview.
+   *
+   * Keep in mind that the variable limit is for the _total_ number of
+   * parameters, including ones bound by name (using the `:VVV`, `@VVV`, or
+   * `?VVV` syntax) and index (`?` and `?NNN`).
+   *
+   * This means, when chunking:
+   *
+   * - If you're binding 1 param per 1 value per chunk (for example, if you
+   *   have a list of GUIDs and a clause like `WHERE guid IN (?, ?, ?, ...)`,
+   *   your chunk length is just `variableLimit`.
+   * - If you're binding 1 param per 1 value per chunk, but using that
+   *   param in multiple positions in the query (for example, `WHERE url_hash
+   *   IN (hash(?1), hash(?2), ...) AND url IN (?1, ?2, ...)`), you can use the
+   *   `?NNN` syntax with a chunk length of `variableLimit`.
+   * - If you're binding N params per 1 value per chunk (for example, if you
+   *   have a list of items with GUIDs and parent GUIDs, and you want to bind
+   *   both), your chunk length is `variableLimit / N`, since you're binding
+   *   two params for each element.
+   * - If you're binding K params per L values per chunk, plus M fixed ones
+   *   (for example, `WHERE parentGuid = :parentGuid AND guid IN (?, ?, ...)`),
+   *   your chunk length is `variableLimit - M`, to ensure there's space for the
+   *   fixed variables.
+   *
+   * If you bind more params than this limit, `create{Async}Statement` will
+   * fail with a "too many SQL variables" error.
+   */
+  readonly attribute int32_t variableLimit;
+
+  /**
+   * Returns true if a transaction is active on this connection.
+   *
+   * Note that this is true if a transaction is active on the connection,
+   * regardless of how it was opened. There are several ways to open one:
+   *
+   * 1. Explicitly calling `beginTransaction` on a `mozIStorageConnection`.
+   * 2. Calling `executeSimpleSQL("BEGIN")` or
+   *    `createStatement("BEGIN").execute()` on a `mozIStorageConnection`.
+   * 3. Executing an async statement, like
+   *    `createAsyncStatement("BEGIN").executeAsync(...)`. This is what
+   *    `Sqlite.sys.mjs` does under the hood.
+   *
+   * Because of this, it's important *not* to use this attribute to decide
+   * whether to *commit* the active transaction, because the caller that opened
+   * it may not expect that. This is why both `mozStorageTransaction` and
+   * `Sqlite.sys.mjs` use an internal variable (`mHasTransaction` for the former;
+   * `_hasInProgressTransaction` for the latter) to check if their transaction
+   * is already in progress, instead of just checking this attribute before
+   * committing. Otherwise, mozStorage might accidentally commit (or roll back!)
+   * a transaction started by `Sqlite.sys.mjs`, and vice versa.
+   */
+  readonly attribute boolean transactionInProgress;
+
+  /**
+   * Close this database connection, allowing all pending statements
+   * to complete first.
+   *
+   * @param aCallback [optional]
+   *        A callback that will be notified when the close is completed,
+   *        with the following arguments:
+   *        - status: the status of the call
+   *        - value: |null|
+   *
+   * @throws NS_ERROR_NOT_SAME_THREAD
+   *         If called on a thread other than the one that opened it.  The
+   *         callback will not be dispatched.
+   * @throws NS_ERROR_NOT_INITIALIZED
+   *         If called on a connection that has already been closed or was
+   *         never properly opened.  The callback will still be dispatched
+   *         to the main thread despite the returned error.
+   * @note If this call should fail, the callback won't be invoked.
+   */
+  void asyncClose([optional] in mozIStorageCompletionCallback aCallback);
+
+  /**
+   * Forcibly closes a database connection synchronously.
+   * This should only be used when it's required to close and replace the
+   * database synchronously to return control to the consumer, for example in
+   * case of a detected corruption on database opening.
+   * Since this spins the events loop, it should be used only in very particular
+   * and rare situations, or it may cause unexpected consequences (crashes).
+   *
+   * @throws NS_ERROR_NOT_SAME_THREAD
+   *         If called on a thread other than the one that opened it.
+   */
+  [noscript] void spinningSynchronousClose();
+
+  /**
+   * Clone a database connection and make the clone read only if needed.
+   * SQL Functions and attached on-disk databases are applied to the new clone.
+   *
+   * @param aReadOnly
+   *        If true, the returned database should be put into read-only mode.
+   *
+   * @param aCallback
+   *        A callback that will be notified when the operation is complete,
+   *        with the following arguments:
+   *        - status: the status of the operation
+   *        - value: in case of success, an intance of
+   *             mozIStorageAsyncConnection cloned from this one.
+   *
+   * @throws NS_ERROR_NOT_SAME_THREAD
+   *         If is called on a thread other than the one that opened it.
+   * @throws NS_ERROR_UNEXPECTED
+   *         If this connection is a memory database.
+   *
+   * @note If your connection is already read-only, you will get a read-only
+   *       clone.
+   * @note The resulting connection will implement `mozIStorageConnection`, but
+   *       all synchronous methods will throw if called from the main thread.
+   * @note Due to a bug in SQLite, if you use the shared cache
+   *       (see mozIStorageService), you end up with the same privileges as the
+   *       first connection opened regardless of what is specified in aReadOnly.
+   * @note The following pragmas are copied over to a read-only clone:
+   *        - cache_size
+   *        - temp_store
+   *       The following pragmas are copied over to a writeable clone:
+   *        - cache_size
+   *        - temp_store
+   *        - foreign_keys
+   *        - journal_size_limit
+   *        - synchronous
+   *        - wal_autocheckpoint
+   *       All SQL functions are copied over to read-only and writeable clones.
+   *       Additionally, all temporary tables, triggers, and views, as well as
+   *       any indexes on temporary tables, are copied over to writeable clones.
+   *       For temporary tables, only the schemas are copied, not their
+   *       contents.
+   */
+  void asyncClone(in boolean aReadOnly,
+                  in mozIStorageCompletionCallback aCallback);
+
+  /**
+   * The current database nsIFile.  Null if the database
+   * connection refers to an in-memory database.
+   */
+  readonly attribute nsIFile databaseFile;
+
+  /**
+   * Causes any pending database operation to abort and return at the first
+   * opportunity.
+   * @note this cannot be used on mozIStorageConnection unless the connection is
+   *       explicitly marked as `interruptible`. For more details, please
+   *       refer to CONNECTION_INTERRUPTIBLE in mozIStorageService.
+   * @note operations that are nearly complete may still be able to complete.
+   * @throws if used on an unsupported connection type, or a closed connection.
+   */
+  void interrupt();
+
+  /**
+   * Vacuum the main database plus all the attached one.
+   * If the database is in auto_vacuum = INCREMENTAL mode, this executes an
+   * incremental_vacuum, otherwise it will always execute a full vacuum.
+   *
+   * While it's possible to invoke this method directly, it's suggested, when
+   * possible, to use the VacuumManager instead.
+   * That means registering your component for the "vacuum-participant" XPCOM
+   * category, and implement the mozIStorageVacuumParticipant interface.
+   *
+   * @param [aCallback] Completion callback invoked once the operation is
+   *        complete.
+   * @param [aUseIncremental] When set to true, this will try to convert the
+   *        main schema to auto_vacuum = INCREMENTAL mode, if it's not set yet.
+   *        When set to false, it will try to set auto_vacuum = NONE.
+   *        Note a full vacuum will be executed if the auto_vacuum mode must be
+   *        changed, otherwise an incremental vacuum will happen if the database
+   *        is already in INCREMENTAL mode.
+   * @param [aSetPageSize] This can be used to change the database page_size, a
+   *        full vacuum will be executed to persist the change. If the page
+   *        size is already correct, or you pass 0, this will be a no-op.
+   * @throws If it's not possible to start the async vacuum operation, note in
+   *         this case the callback won't be invoked.
+   * @note Vacuum will fail inside a transaction, or if there is an ongoing
+   *       read statement.
+   */
+  void asyncVacuum(
+    [optional] in mozIStorageCompletionCallback aCallback,
+    [optional] in boolean aUseIncremental,
+    [optional] in long aSetPageSize
+  );
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// Statement creation
+
+  /**
+   * Create an asynchronous statement for the given SQL. An
+   * asynchronous statement can only be used to dispatch asynchronous
+   * requests to the asynchronous execution thread and cannot be used
+   * to take any synchronous actions on the database.
+   *
+   * The expression may use ? to indicate sequential numbered arguments,
+   * ?1, ?2 etc. to indicate specific numbered arguments or :name and
+   * $var to indicate named arguments.
+   *
+   * @param aSQLStatement
+   *        The SQL statement to execute.
+   * @return a new mozIStorageAsyncStatement
+   * @note The statement is created lazily on first execution.
+   */
+  mozIStorageAsyncStatement createAsyncStatement(in AUTF8String aSQLStatement);
+
+  /**
+   * Execute an array of statements created with this connection using
+   * any currently bound parameters. When the array contains multiple
+   * statements, the execution is wrapped in a single
+   * transaction. These statements can be reused immediately, and
+   * reset does not need to be called.
+   *
+   * @param aStatements
+   *        The array of statements to execute asynchronously, in the order they
+   *        are given in the array.
+   * @param aCallback [optional]
+   *        The callback object that will be notified of progress, errors, and
+   *        completion.
+   * @return an object that can be used to cancel the statements execution.
+   *
+   * @note If you have any custom defined functions, they must be
+   *        re-entrant since they can be called on multiple threads.
+   */
+  mozIStoragePendingStatement executeAsync(
+    in Array<mozIStorageBaseStatement> aStatements,
+    [optional] in mozIStorageStatementCallback aCallback
+  );
+
+  /**
+   * Execute asynchronously an SQL expression, expecting no arguments.
+   *
+   * @param aSQLStatement
+   *        The SQL statement to execute
+   * @param aCallback [optional]
+   *        The callback object that will be notified of progress, errors, and
+   *        completion.
+   * @return an object that can be used to cancel the statement execution.
+   */
+  mozIStoragePendingStatement executeSimpleSQLAsync(
+    in AUTF8String aSQLStatement,
+    [optional] in mozIStorageStatementCallback aCallback);
+
+
+  /**
+   * Loads a Sqlite Run-Time Loadable Extension as defined at
+   * https://www.sqlite.org/loadext.html.
+   * Only a predetermined list of extensions can be loaded, that are statically
+   * linked in the shared library containing SQLite. The currently supported
+   * extensions are:
+   *   - fts5
+   *     A Full-Text search module, see https://www.sqlite.org/fts5.html
+   *
+   * New extensions can be added to the third_party/sqlite3/ext/ folder and then
+   * to this list, after a Storage peer has reviewed the request by verifying
+   * licensing, and code reliability.
+   * Extensions that must be loaded for all the connections should instead use
+   * sqlite3_auto_extension() (this must happen after sqlite3_config(), as it
+   * implicitly calls sqlite3_initialize()).
+   *
+   * @param aExtensionName
+   *        The extension to load, see the above list for supported values.
+   * @param aCallback
+   *        A callback that will be notified when the operation is complete,
+   *        with the following arguments:
+   *        - status: the status of the operation, use this to check if loading
+   *          the extension was successful as it may be partly asynchronous.
+   *        - value: unused.
+   * @throws NS_ERROR_INVALID_ARG
+   *         For unsupported extension names.
+   * @throws NS_ERROR_NOT_INITIALIZED
+   *         If the connection is not open.
+   * @throws NS_ERROR_UEXPECTED
+   *         If it was not possible to enable extensions loading.
+   */
+  void loadExtension(in AUTF8String aExtensionName,
+                     [optional] in mozIStorageCompletionCallback aCallback);
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// Functions
+
+  /**
+   * Create a new SQL function.  If you use your connection on multiple threads,
+   * your function needs to be threadsafe, or it should only be called on one
+   * thread.
+   *
+   * @param aFunctionName
+   *        The name of function to create, as seen in SQL.
+   * @param aNumArguments
+   *        The number of arguments the function takes. Pass -1 for
+   *        variable-argument functions.
+   * @param aFunction
+   *        The instance of mozIStorageFunction, which implements the function
+   *        in question.
+   */
+  void createFunction(in AUTF8String aFunctionName,
+                      in long aNumArguments,
+                      in mozIStorageFunction aFunction);
+
+  /**
+   * Delete custom SQL function.
+   *
+   * @param aFunctionName
+   *        The name of function to remove.
+   */
+  void removeFunction(in AUTF8String aFunctionName);
+
+  /**
+   * Sets a progress handler. Only one handler can be registered at a time.
+   * If you need more than one, you need to chain them yourself.  This progress
+   * handler should be threadsafe if you use this connection object on more than
+   * one thread.
+   *
+   * @param aGranularity
+   *        The number of SQL virtual machine steps between progress handler
+   *        callbacks.
+   * @param aHandler
+   *        The instance of mozIStorageProgressHandler.
+   * @return previous registered handler.
+   */
+  mozIStorageProgressHandler setProgressHandler(in int32_t aGranularity,
+                                                in mozIStorageProgressHandler aHandler);
+
+  /**
+   * Remove a progress handler.
+   *
+   * @return previous registered handler.
+   */
+  mozIStorageProgressHandler removeProgressHandler();
+
+  /**
+   * Makes a copy of a database asynchronously. This method can do an online
+   * backup of the database file, even if there are open connections actively
+   * using it (as a normal file copy can only be made if no connections are
+   * open on the database).
+   *
+   * While the copy is in the process of being made, the destination file
+   * will have a .tmp extension appended to it. In the event of a crash
+   * during the copy, this .tmp file will continue to exist, but will be
+   * an unusable partial copy.
+   *
+   * Once the copy has been completed, this method will automatically remove
+   * the .tmp extension.
+   *
+   * @param aDestinationFile
+   *        The destination on the file system to write the database copy.
+   * @param aCallback
+   *        A callback that will be notified when the operation is complete,
+   *        with the following arguments:
+   *        - status: the status of the operation, use this to check if making
+   *                  the copy was successful.
+   *        - value: unused.
+   * @throws NS_ERROR_ABORT
+   *         If the application has begun the process of shutting down already.
+   * @throws NS_ERROR_NOT_INITIALIZED
+   *         If the connection has already started or completed closing.
+   * @throws NS_ERROR_NOT_AVAILABLE
+   *         If the database does not support asynchronous operations.
+   * @throws NS_ERROR_NOT_INITIALIZED
+   *         If the execution thread cannot be acquired.
+   */
+  void backupToFileAsync(in nsIFile aDestinationFile,
+                         in mozIStorageCompletionCallback aCallback);
+};
diff --git a/storage/mozIStorageAsyncStatement.idl b/storage/mozIStorageAsyncStatement.idl
new file mode 100644
index 0000000000..de7369fcaa
--- /dev/null
+++ b/storage/mozIStorageAsyncStatement.idl
@@ -0,0 +1,37 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 sts=2 expandtab
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozIStorageBaseStatement.idl"
+
+/**
+ * An asynchronous SQL statement.  This differs from mozIStorageStatement by
+ * only being usable for asynchronous execution.  (mozIStorageStatement can
+ * be used for both synchronous and asynchronous purposes.)  This specialization
+ * for asynchronous operation allows us to avoid needing to acquire
+ * synchronization primitives also used by the asynchronous execution thread.
+ * In contrast, mozIStorageStatement may need to acquire the primitives and
+ * consequently can cause the main thread to lock for extended intervals while
+ * the asynchronous thread performs some long-running operation.
+ */
+[scriptable, builtinclass, uuid(52e49370-3b2e-4a27-a3fc-79e20ad4056b)]
+interface mozIStorageAsyncStatement : mozIStorageBaseStatement {
+  /*
+   * 'params' provides a magic JS helper that lets you assign parameters by
+   * name.  Unlike the helper on mozIStorageStatement, you cannot enumerate
+   * in order to find out what parameters are legal.
+   *
+   * This does not work for BLOBs.  You must use an explicit binding API for
+   * that.
+   *
+   * example:
+   *  stmt.params.foo = 1;
+   *  stmt.params["bar"] = 2;
+   *  let argName = "baz";
+   *  stmt.params[argName] = 3;
+   *
+   * readonly attribute nsIMagic params;
+   */
+};
diff --git a/storage/mozIStorageBaseStatement.idl b/storage/mozIStorageBaseStatement.idl
new file mode 100644
index 0000000000..cd869d8fde
--- /dev/null
+++ b/storage/mozIStorageBaseStatement.idl
@@ -0,0 +1,125 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 sts=2 et
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+#include "mozIStorageBindingParams.idl"
+
+interface mozIStorageConnection;
+interface mozIStorageStatementCallback;
+interface mozIStoragePendingStatement;
+interface mozIStorageBindingParams;
+interface mozIStorageBindingParamsArray;
+
+/**
+ * The base interface for both pure asynchronous storage statements
+ * (mozIStorageAsyncStatement) and 'classic' storage statements
+ * (mozIStorageStatement) that can be used for both synchronous and asynchronous
+ * purposes.
+ */
+[scriptable, builtinclass, uuid(16ca67aa-1325-43e2-aac7-859afd1590b2)]
+interface mozIStorageBaseStatement : mozIStorageBindingParams {
+  /**
+   * Finalizes a statement so you can successfully close a database connection.
+   * Once a statement has been finalized it can no longer be used for any
+   * purpose.
+   *
+   * Statements are implicitly finalized when their reference counts hits zero.
+   * If you are a native (C++) caller this is accomplished by setting all of
+   * your nsCOMPtr instances to be NULL.  If you are operating from JavaScript
+   * code then you cannot rely on this behavior because of the involvement of
+   * garbage collection.
+   *
+   * When finalizing an asynchronous statement you do not need to worry about
+   * whether the statement has actually been executed by the asynchronous
+   * thread; you just need to call finalize after your last call to executeAsync
+   * involving the statement.  However, you do need to use asyncClose instead of
+   * close on the connection if any statements have been used asynchronously.
+   */
+  void finalize();
+
+  /**
+   * Binds the array of parameters to the statement.  When executeAsync is
+   * called, all the parameters in aParameters are bound and then executed.
+   *
+   * @param aParameters
+   *        The array of parameters to bind to the statement upon execution.
+   *
+   * @note This is only works on statements being used asynchronously.
+   */
+  void bindParameters(in mozIStorageBindingParamsArray aParameters);
+
+  /**
+   * Creates a new mozIStorageBindingParamsArray that can be used to bind
+   * multiple sets of data to a statement with bindParameters.
+   *
+   * @return a mozIStorageBindingParamsArray that multiple sets of parameters
+   *         can be bound to.
+   *
+   * @note This is only useful for statements being used asynchronously.
+   */
+  mozIStorageBindingParamsArray newBindingParamsArray();
+
+  /**
+   * Execute a query asynchronously using any currently bound parameters.  This
+   * statement can be reused immediately, and reset does not need to be called.
+   *
+   * @note If you have any custom defined functions, they must be re-entrant
+   *       since they can be called on multiple threads.
+   *
+   * @param aCallback [optional]
+   *        The callback object that will be notified of progress, errors, and
+   *        completion.
+   * @return an object that can be used to cancel the statements execution.
+   */
+  mozIStoragePendingStatement executeAsync(
+    [optional] in mozIStorageStatementCallback aCallback
+  );
+
+  /**
+   * The statement is not usable, either because it failed to initialize or
+   * was explicitly finalized.
+   */
+  const long MOZ_STORAGE_STATEMENT_INVALID = 0;
+  /**
+   * The statement is usable.
+   */
+  const long MOZ_STORAGE_STATEMENT_READY = 1;
+  /**
+   * Indicates that the statement is executing and the row getters may be used.
+   *
+   * @note This is only relevant for mozIStorageStatement instances being used
+   *       in a synchronous fashion.
+   */
+  const long MOZ_STORAGE_STATEMENT_EXECUTING = 2;
+
+  /**
+   * Find out whether the statement is usable (has not been finalized).
+   */
+  readonly attribute long state;
+
+  /**
+   * Escape a string for SQL LIKE search.
+   *
+   * @note Consumers will have to use same escape char when doing statements
+   *       such as:   ...LIKE '?1' ESCAPE '/'...
+   *
+   * @param aValue
+   *        The string to escape for SQL LIKE.
+   * @param aEscapeChar
+   *        The escape character.
+   * @return an AString of an escaped version of aValue
+   *         (%, _ and the escape char are escaped with the escape char)
+   *         For example, we will convert "foo/bar_baz%20cheese"
+   *         into "foo//bar/_baz/%20cheese" (if the escape char is '/').
+   */
+  AString escapeStringForLIKE(in AString aValue, in wchar aEscapeChar);
+
+  /**
+   * The same as above, but for UTF8 strings.
+   */
+  AUTF8String escapeUTF8StringForLIKE(in AUTF8String aValue,
+                                      in char aEscapeChar);
+};
diff --git a/storage/mozIStorageBindingParams.idl b/storage/mozIStorageBindingParams.idl
new file mode 100644
index 0000000000..6a5279e07d
--- /dev/null
+++ b/storage/mozIStorageBindingParams.idl
@@ -0,0 +1,103 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 sts=2 et
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface nsIVariant;
+
+[ptr] native octetPtr(uint8_t);
+
+[scriptable, builtinclass, uuid(2d09f42f-966e-4663-b4b3-b0c8676bf2bf)]
+interface mozIStorageBindingParams : nsISupports {
+  /**
+   * Binds aValue to the parameter with the name aName.
+   *
+   * @param aName
+   *        The name of the parameter to bind aValue to.
+   * @param aValue
+   *        The value to bind.
+   */
+   void bindByName(in AUTF8String aName,
+                   in nsIVariant aValue);
+   [noscript] void bindUTF8StringByName(in AUTF8String aName,
+                                        in AUTF8String aValue);
+   [noscript] void bindStringByName(in AUTF8String aName,
+                                    in AString aValue);
+   [noscript] void bindDoubleByName(in AUTF8String aName,
+                                    in double aValue);
+   [noscript] void bindInt32ByName(in AUTF8String aName,
+                                   in long aValue);
+   [noscript] void bindInt64ByName(in AUTF8String aName,
+                                   in long long aValue);
+   [noscript] void bindNullByName(in AUTF8String aName);
+
+   // The noscript version of bindBlobByName can be used with any (const
+   // uint8_t*, length) pair.  The scriptable version is meant for use with
+   // nsTArray<uint8_t>, which is what xpconnect has to work with.
+   [noscript, binaryname(BindBlobByName)]
+   void bindBlobByNameNoscript(in AUTF8String aName,
+                               [const] in octetPtr aValue,
+                               in unsigned long aValueSize);
+   [binaryname(BindBlobArrayByName)]
+   void bindBlobByName(in AUTF8String aName, in Array<octet> aValue);
+
+   // Convenience routines for storing strings as blobs.
+   void bindStringAsBlobByName(in AUTF8String aName, in AString aValue);
+   void bindUTF8StringAsBlobByName(in AUTF8String aName, in AUTF8String aValue);
+
+   // The function adopts the storage for the provided blob.  After calling
+   // this function, mozStorage will ensure that free is called on the
+   // underlying pointer.
+   [noscript]
+   void bindAdoptedBlobByName(in AUTF8String aName,
+                              in octetPtr aValue,
+                              in unsigned long aValueSize);
+
+   /**
+    * Binds aValue to the parameter with the index aIndex.
+    *
+    * @param aIndex
+    *        The zero-based index of the parameter to bind aValue to.
+    * @param aValue
+    *        The value to bind.
+    */
+   void bindByIndex(in unsigned long aIndex,
+                    in nsIVariant aValue);
+   [noscript] void bindUTF8StringByIndex(in unsigned long aIndex,
+                                         in AUTF8String aValue);
+   [noscript] void bindStringByIndex(in unsigned long aIndex,
+                                     in AString aValue);
+   [noscript] void bindDoubleByIndex(in unsigned long aIndex,
+                                     in double aValue);
+   [noscript] void bindInt32ByIndex(in unsigned long aIndex,
+                                    in long aValue);
+   [noscript] void bindInt64ByIndex(in unsigned long aIndex,
+                                    in long long aValue);
+   [noscript] void bindNullByIndex(in unsigned long aIndex);
+
+   // The noscript version of bindBlobByIndex can be used with any (const
+   // uint8_t*, length) pair.  The scriptable version is meant for use with
+   // nsTArray<uint8_t>, which is what xpconnect has to work with.
+   [noscript, binaryname(BindBlobByIndex)]
+   void bindBlobByIndexNoscript(in unsigned long aIndex,
+                                [const] in octetPtr aValue,
+                                in unsigned long aValueSize);
+   [binaryname(BindBlobArrayByIndex)]
+   void bindBlobByIndex(in unsigned long aIndex,
+                        in Array<octet> aValue);
+
+   // Convenience routines for storing strings as blobs.
+   void bindStringAsBlobByIndex(in unsigned long aIndex, in AString aValue);
+   void bindUTF8StringAsBlobByIndex(in unsigned long aIndex, in AUTF8String aValue);
+
+   // The function adopts the storage for the provided blob.  After calling
+   // this function, mozStorage will ensure that free is called on the
+   // underlying pointer.
+   [noscript]
+   void bindAdoptedBlobByIndex(in unsigned long aIndex,
+                               in octetPtr aValue,
+                               in unsigned long aValueSize);
+};
diff --git a/storage/mozIStorageBindingParamsArray.idl b/storage/mozIStorageBindingParamsArray.idl
new file mode 100644
index 0000000000..5f504c0514
--- /dev/null
+++ b/storage/mozIStorageBindingParamsArray.idl
@@ -0,0 +1,34 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 sts=2 et
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface mozIStorageBindingParams;
+
+[scriptable, uuid(67eea5c3-4881-41ff-b0fe-09f2356aeadb)]
+interface mozIStorageBindingParamsArray : nsISupports {
+  /**
+   * Creates a new mozIStorageBindingParams object that can be added to this
+   * array.
+   *
+   * @return a mozIStorageBindingParams object that can be used to specify
+   *         parameters that need to be bound.
+   */
+  mozIStorageBindingParams newBindingParams();
+
+  /**
+   * Adds the parameters to the end of this array.
+   *
+   * @param aParameters
+   *        The parameters to add to this array.
+   */
+  void addParams(in mozIStorageBindingParams aParameters);
+
+  /**
+   * The number of mozIStorageBindingParams this object contains.
+   */
+  readonly attribute unsigned long length;
+};
diff --git a/storage/mozIStorageCompletionCallback.idl b/storage/mozIStorageCompletionCallback.idl
new file mode 100644
index 0000000000..1c31cc2c26
--- /dev/null
+++ b/storage/mozIStorageCompletionCallback.idl
@@ -0,0 +1,24 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+  vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+[scriptable, function, uuid(8cbf2dc2-91e0-44bc-984f-553638412071)]
+interface mozIStorageCompletionCallback : nsISupports {
+  /**
+   * Indicates that the event this callback was passed in for has completed.
+   *
+   * @param status
+   *        The status of the call. Generally NS_OK if the operation
+   *        completed successfully.
+   * @param value
+   *        If the operation produces a result, the result. Otherwise,
+   *        |null|.
+   *
+   * @see The calling method for expected values.
+   */
+  void complete(in nsresult status, [optional] in nsISupports value);
+};
diff --git a/storage/mozIStorageConnection.idl b/storage/mozIStorageConnection.idl
new file mode 100644
index 0000000000..34217b5f42
--- /dev/null
+++ b/storage/mozIStorageConnection.idl
@@ -0,0 +1,283 @@
+/* -*- Mode: idl; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+#include "mozIStorageAsyncConnection.idl"
+
+%{C++
+namespace mozilla::dom::quota {
+class QuotaObject;
+}
+
+namespace mozilla::storage {
+class SQLiteMutex;
+class SQLiteMutexAutoLock;
+}
+
+%}
+
+[ptr] native QuotaObject(mozilla::dom::quota::QuotaObject);
+native SQLiteMutex(mozilla::storage::SQLiteMutex&);
+native SQLiteMutexAutoLock(const mozilla::storage::SQLiteMutexAutoLock&);
+
+interface mozIStorageAggregateFunction;
+interface mozIStorageCompletionCallback;
+interface mozIStorageFunction;
+interface mozIStorageProgressHandler;
+interface mozIStorageBaseStatement;
+interface mozIStorageStatement;
+interface mozIStorageAsyncStatement;
+interface mozIStorageStatementCallback;
+interface mozIStoragePendingStatement;
+interface nsIFile;
+
+/**
+ * mozIStorageConnection represents a database connection attached to
+ * a specific file or to the in-memory data storage.  It is the
+ * primary interface for interacting with a database, including
+ * creating prepared statements, executing SQL, and examining database
+ * errors.
+ *
+ * @note From the main thread, you should rather use mozIStorageAsyncConnection.
+ *
+ * @threadsafe
+ */
+[scriptable, builtinclass, uuid(4aa2ac47-8d24-4004-9b31-ec0bd85f0cc3)]
+interface mozIStorageConnection : mozIStorageAsyncConnection {
+  /**
+   * Closes a database connection.  Callers must finalize all statements created
+   * for this connection prior to calling this method.  It is illegal to use
+   * call this method if any asynchronous statements have been executed on this
+   * connection.
+   *
+   * @throws NS_ERROR_UNEXPECTED
+   *         If any statement has been executed asynchronously on this object.
+   * @throws NS_ERROR_UNEXPECTED
+   *         If is called on a thread other than the one that opened it.
+   */
+  void close();
+
+  /**
+   * Clones a database connection and makes the clone read only if needed.
+   * SQL Functions and attached on-disk databases are applied to the new clone.
+   *
+   * @param aReadOnly
+   *        If true, the returned database should be put into read-only mode.
+   *        Defaults to false.
+   * @return the cloned database connection.
+   *
+   * @throws NS_ERROR_UNEXPECTED
+   *         If this connection is a memory database.
+   * @note If your connection is already read-only, you will get a read-only
+   *       clone.
+   * @note Due to a bug in SQLite, if you use the shared cache (openDatabase),
+   *       you end up with the same privileges as the first connection opened
+   *       regardless of what is specified in aReadOnly.
+   * @note The following pragmas are copied over to a read-only clone:
+   *        - cache_size
+   *        - temp_store
+   *       The following pragmas are copied over to a writeable clone:
+   *        - cache_size
+   *        - temp_store
+   *        - foreign_keys
+   *        - journal_size_limit
+   *        - synchronous
+   *        - wal_autocheckpoint
+   *       All SQL functions are copied over to read-only and writeable clones.
+   *       Additionally, all temporary tables, triggers, and views, as well as
+   *       any indexes on temporary tables, are copied over to writeable clones.
+   *       For temporary tables, only the schemas are copied, not their
+   *       contents.
+   *
+   */
+  mozIStorageConnection clone([optional] in boolean aReadOnly);
+
+  /**
+   * The default size for SQLite database pages used by mozStorage for new
+   * databases.
+   */
+  readonly attribute long defaultPageSize;
+
+  /**
+   * Indicates if the connection is open and ready to use.  This will be false
+   * if the connection failed to open, or it has been closed.
+   */
+  readonly attribute boolean connectionReady;
+
+  /**
+   * lastInsertRowID returns the row ID from the last INSERT
+   * operation.
+   */
+  readonly attribute long long lastInsertRowID;
+
+  /**
+   * affectedRows returns the number of database rows that were changed or
+   * inserted or deleted by last operation.
+   */
+  readonly attribute long affectedRows;
+
+  /**
+   * The last error SQLite error code.
+   */
+  readonly attribute long lastError;
+
+  /**
+   * The last SQLite error as a string (in english, straight from the
+   * sqlite library).
+   */
+  readonly attribute AUTF8String lastErrorString;
+
+  /**
+   * The schema version of the database.  This should not be used until the
+   * database is ready.  The schema will be reported as zero if it is not set.
+   */
+  attribute long schemaVersion;
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// Statement creation
+
+  /**
+   * Create a mozIStorageStatement for the given SQL expression.  The
+   * expression may use ? to indicate sequential numbered arguments,
+   * ?1, ?2 etc. to indicate specific numbered arguments or :name and
+   * $var to indicate named arguments.
+   *
+   * @param aSQLStatement
+   *        The SQL statement to execute.
+   * @return a new mozIStorageStatement
+   */
+  mozIStorageStatement createStatement(in AUTF8String aSQLStatement);
+
+  /**
+   * Execute a SQL expression, expecting no arguments.
+   *
+   * @param aSQLStatement  The SQL statement to execute
+   */
+  void executeSimpleSQL(in AUTF8String aSQLStatement);
+
+  /**
+   * Check if the given table exists.
+   *
+   * @param aTableName
+   *        The table to check
+   * @return TRUE if table exists, FALSE otherwise.
+   */
+  boolean tableExists(in AUTF8String aTableName);
+
+  /**
+   * Check if the given index exists.
+   *
+   * @param aIndexName   The index to check
+   * @return TRUE if the index exists, FALSE otherwise.
+   */
+  boolean indexExists(in AUTF8String aIndexName);
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// Transactions
+
+  /**
+   * Begin a new transaction. If a transaction is active, throws an error.
+   */
+  void beginTransaction();
+
+  /**
+   * Commits the current transaction.  If no transaction is active,
+   * @throws NS_ERROR_UNEXPECTED.
+   * @throws NS_ERROR_NOT_INITIALIZED.
+   */
+  void commitTransaction();
+
+  /**
+   * Rolls back the current transaction.  If no transaction is active,
+   * @throws NS_ERROR_UNEXPECTED.
+   * @throws NS_ERROR_NOT_INITIALIZED.
+   */
+  void rollbackTransaction();
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// Tables
+
+  /**
+   * Create the table with the given name and schema.
+   *
+   * If the table already exists, NS_ERROR_FAILURE is thrown.
+   * (XXX at some point in the future it will check if the schema is
+   * the same as what is specified, but that doesn't happen currently.)
+   *
+   * @param aTableName
+   *        The table name to be created, consisting of [A-Za-z0-9_], and
+   *        beginning with a letter.
+   * @param aTableSchema
+   *        The schema of the table; what would normally go between the parens
+   *        in a CREATE TABLE statement: e.g., "foo  INTEGER, bar STRING".
+   *
+   * @throws NS_ERROR_FAILURE
+   *         If the table already exists or could not be created for any other
+   *         reason.
+   */
+  void createTable(in string aTableName,
+                   in string aTableSchema);
+
+  /**
+   * Controls SQLITE_FCNTL_CHUNK_SIZE setting in sqlite. This helps avoid fragmentation
+   * by growing/shrinking the database file in SQLITE_FCNTL_CHUNK_SIZE increments. To
+   * conserve memory on systems short on storage space, this function will have no effect
+   * on mobile devices or if less than 500MiB of space is left available.
+   *
+   * @param aIncrement
+   *        The database file will grow in multiples of chunkSize.
+   * @param aDatabaseName
+   *        Sqlite database name. "" means pass NULL for zDbName to sqlite3_file_control.
+   *        See http://sqlite.org/c3ref/file_control.html for more details.
+   * @throws NS_ERROR_FILE_TOO_BIG
+   *         If the system is short on storage space.
+   */
+  void setGrowthIncrement(in int32_t aIncrement, in AUTF8String aDatabaseName);
+
+  /**
+   * Enable a predefined virtual table implementation.
+   *
+   * @param aModuleName
+   *        The module to enable. Only "filesystem" is currently supported.
+   *
+   * @throws NS_ERROR_FAILURE
+   *         For unknown module names.
+   */
+  [noscript] void enableModule(in ACString aModuleName);
+
+  /**
+   * Get quota objects.
+   *
+   * @param[out] aDatabaseQuotaObject
+   *             The QuotaObject associated with the database file.
+   * @param[out] aJournalQuotaObject
+   *             The QuotaObject associated with the journal file.
+   *
+   * @throws NS_ERROR_NOT_INITIALIZED.
+   */
+  [noscript] void getQuotaObjects(out QuotaObject aDatabaseQuotaObject,
+                                  out QuotaObject aJournalQuotaObject);
+
+  /**
+   * The mutex used for protection of operations (BEGIN/COMMIT/ROLLBACK) in
+   * mozStorageTransaction. The lock must be held in a way that spans whole
+   * operation, not just when accessing the nesting level.
+   */
+  [notxpcom, nostdcall] readonly attribute SQLiteMutex sharedDBMutex;
+
+  /**
+   * Helper methods for managing the transaction nesting level. The methods
+   * must be called with a proof of lock. Currently only used by
+   * mozStorageTransaction.
+   */
+  [notxpcom, nostdcall] unsigned long getTransactionNestingLevel(
+      in SQLiteMutexAutoLock aProofOfLock);
+
+  [notxpcom, nostdcall] unsigned long increaseTransactionNestingLevel(
+      in SQLiteMutexAutoLock aProofOfLock);
+
+  [notxpcom, nostdcall] unsigned long decreaseTransactionNestingLevel(
+      in SQLiteMutexAutoLock aProofOfLock);
+};
diff --git a/storage/mozIStorageError.idl b/storage/mozIStorageError.idl
new file mode 100644
index 0000000000..1c6df5bb69
--- /dev/null
+++ b/storage/mozIStorageError.idl
@@ -0,0 +1,149 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 sts=2 expandtab
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+%{C++
+#ifdef ERROR
+#undef ERROR
+#endif
+%}
+
+[scriptable, uuid(1f350f96-7023-434a-8864-40a1c493aac1)]
+interface mozIStorageError : nsISupports {
+
+  /**
+   * General SQL error or missing database.
+   */
+  const long ERROR = 1;
+
+  /**
+   * Internal logic error.
+   */
+  const long INTERNAL = 2;
+
+  /**
+   * Access permission denied.
+   */
+  const long PERM = 3;
+
+  /**
+   * A callback routine requested an abort.
+   */
+  const long ABORT = 4;
+
+  /**
+   * The database file is locked.
+   */
+  const long BUSY = 5;
+
+  /**
+   * A table in the database is locked.
+   */
+  const long LOCKED = 6;
+
+  /**
+   * An allocation failed.
+   */
+  const long NOMEM = 7;
+
+  /**
+   * Attempt to write to a readonly database.
+   */
+  const long READONLY = 8;
+
+  /**
+   * Operation was terminated by an interrupt.
+   */
+  const long INTERRUPT = 9;
+
+  /**
+   * Some kind of disk I/O error occurred.
+   */
+  const long IOERR = 10;
+
+  /**
+   * The database disk image is malformed.
+   */
+  const long CORRUPT = 11;
+
+  /**
+   * An insertion failed because the database is full.
+   */
+  const long FULL = 13;
+
+  /**
+   * Unable to open the database file.
+   */
+  const long CANTOPEN = 14;
+
+  /**
+   * The database is empty.
+   */
+  const long EMPTY = 16;
+
+  /**
+   * The database scheme changed.
+   */
+  const long SCHEMA = 17;
+
+  /**
+   * A string or blob exceeds the size limit.
+   */
+  const long TOOBIG = 18;
+
+  /**
+   * Abort due to a constraint violation.
+   */
+  const long CONSTRAINT = 19;
+
+  /**
+   * Data type mismatch.
+   */
+  const long MISMATCH = 20;
+
+  /**
+   * Library used incorrectly.
+   */
+  const long MISUSE = 21;
+
+  /**
+   * Uses OS features not supported on the host system.
+   */
+  const long NOLFS = 22;
+
+  /**
+   * Authorization denied.
+   */
+  const long AUTH = 23;
+
+  /**
+   * Auxiliary database format error.
+   */
+  const long FORMAT = 24;
+
+  /**
+   * Attempt to bind a parameter using an out-of-range index or nonexistent
+   * named parameter name.
+   */
+  const long RANGE = 25;
+
+  /**
+   * File opened that is not a database file.
+   */
+  const long NOTADB = 26;
+
+
+  /**
+   * Indicates what type of error occurred.
+   */
+  readonly attribute long result;
+
+  /**
+   * An error string the gives more details, if available.
+   */
+  readonly attribute AUTF8String message;
+};
diff --git a/storage/mozIStorageFunction.idl b/storage/mozIStorageFunction.idl
new file mode 100644
index 0000000000..f4cd8de42e
--- /dev/null
+++ b/storage/mozIStorageFunction.idl
@@ -0,0 +1,40 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+#include "mozIStorageValueArray.idl"
+
+interface mozIStorageConnection;
+interface nsIArray;
+interface nsIVariant;
+
+/**
+ * mozIStorageFunction is to be implemented by storage consumers that
+ * wish to receive callbacks during the request execution.
+ *
+ * SQL can apply functions to values from tables. Examples of
+ * such functions are MIN(a1,a2) or SQRT(num). Many functions are
+ * implemented in SQL engine.
+ *
+ * This interface allows consumers to implement their own,
+ * problem-specific functions.
+ * These functions can be called from triggers, too.
+ *
+ */
+[scriptable, function, uuid(9ff02465-21cb-49f3-b975-7d5b38ceec73)]
+interface mozIStorageFunction : nsISupports {
+  /**
+   * onFunctionCall is called when execution of a custom
+   * function should occur.
+   *
+   * @param aNumArguments         The number of arguments
+   * @param aFunctionArguments    The arguments passed in to the function
+   *
+   * @returns any value as Variant type.
+   */
+
+  nsIVariant onFunctionCall(in mozIStorageValueArray aFunctionArguments);
+};
diff --git a/storage/mozIStoragePendingStatement.idl b/storage/mozIStoragePendingStatement.idl
new file mode 100644
index 0000000000..d1754aec5c
--- /dev/null
+++ b/storage/mozIStoragePendingStatement.idl
@@ -0,0 +1,20 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 sts=2 expandtab
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+[scriptable, uuid(00da7d20-3768-4398-bedc-e310c324b3f0)]
+interface mozIStoragePendingStatement : nsISupports {
+
+  /**
+   * Cancels a pending statement, if possible.  This will only fail if you try
+   * cancel more than once.
+   *
+   * @note For read statements (such as SELECT), you will no longer receive any
+   *       notifications about results once cancel is called.
+   */
+   void cancel();
+};
diff --git a/storage/mozIStorageProgressHandler.idl b/storage/mozIStorageProgressHandler.idl
new file mode 100644
index 0000000000..a619365600
--- /dev/null
+++ b/storage/mozIStorageProgressHandler.idl
@@ -0,0 +1,26 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface mozIStorageConnection;
+
+/**
+ * mozIProgressHandler is to be implemented by storage consumers that
+ * wish to receive callbacks during the request execution.
+ */
+[scriptable, uuid(a3a6fcd4-bf89-4208-a837-bf2a73afd30c)]
+interface mozIStorageProgressHandler : nsISupports {
+  /**
+   * onProgress is invoked periodically during long running calls.
+   *
+   * @param aConnection    connection, for which progress handler is
+   *                       invoked.
+   *
+   * @return true to abort request, false to continue work.
+   */
+
+  boolean onProgress(in mozIStorageConnection aConnection);
+};
diff --git a/storage/mozIStorageResultSet.idl b/storage/mozIStorageResultSet.idl
new file mode 100644
index 0000000000..4edb08d4ca
--- /dev/null
+++ b/storage/mozIStorageResultSet.idl
@@ -0,0 +1,21 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 sts=2 expandtab
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+interface mozIStorageRow;
+
+[scriptable, uuid(18dd7953-076d-4598-8105-3e32ad26ab24)]
+interface mozIStorageResultSet : nsISupports {
+
+  /**
+   * Obtains the next row from the result set from the statement that was
+   * executed.
+   *
+   * @returns the next row from the result set.  This will be null when there
+   *          are no more results.
+   */
+  mozIStorageRow getNextRow();
+};
diff --git a/storage/mozIStorageRow.idl b/storage/mozIStorageRow.idl
new file mode 100644
index 0000000000..f14d7c5c71
--- /dev/null
+++ b/storage/mozIStorageRow.idl
@@ -0,0 +1,33 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 sts=2 expandtab
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozIStorageValueArray.idl"
+interface nsIVariant;
+
+[scriptable, uuid(62d1b6bd-cbfe-4f9b-aee1-0ead4af4e6dc)]
+interface mozIStorageRow : mozIStorageValueArray {
+
+  /**
+   * Obtains the result of a given column specified by aIndex.
+   *
+   * @param aIndex
+   *        Zero-based index of the result to get from the tuple.
+   * @returns the result of the specified column.
+   */
+  nsIVariant getResultByIndex(in unsigned long aIndex);
+
+  /**
+   * Obtains the result of a given column specified by aName.
+   *
+   * @param aName
+   *        Name of the result to get from the tuple.
+   * @returns the result of the specified column.
+   * @note The name of a result column is the value of the "AS" clause for that
+   *       column.  If there is no AS clause then the name of the column is
+   *       unspecified and may change from one release to the next.
+   */
+  nsIVariant getResultByName(in AUTF8String aName);
+};
diff --git a/storage/mozIStorageService.idl b/storage/mozIStorageService.idl
new file mode 100644
index 0000000000..22c1dc0565
--- /dev/null
+++ b/storage/mozIStorageService.idl
@@ -0,0 +1,290 @@
+/* -*- Mode: idl; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+%{C++
+
+#include "nsLiteralString.h"
+
+%}
+
+interface mozIStorageConnection;
+interface nsIFile;
+interface nsIFileURL;
+interface nsIPropertyBag2;
+interface nsIVariant;
+interface mozIStorageCompletionCallback;
+
+/**
+ * PRIVACY WARNING
+ * ===============
+ *
+ * Database file names can be exposed through telemetry and in crash reports on
+ * the https://crash-stats.mozilla.org site, to allow recognizing the affected
+ * database.
+ * if your database name may contain privacy sensitive information, e.g. an
+ * URL origin, you should use openDatabaseWithFileURL and pass an explicit
+ * TelemetryFilename to it. That name will be used both for telemetry and for
+ * thread names in crash reports.
+ * If you have different needs (e.g. using the javascript module or an async
+ * connection from the main thread) please coordinate with the mozStorage peers.
+ */
+
+/**
+ * The mozIStorageService interface is intended to be implemented by
+ * a service that can create storage connections (mozIStorageConnection)
+ * to either a well-known profile database or to a specific database file.
+ *
+ * This is the only way to open a database connection.
+ *
+ * @note The first reference to mozIStorageService must be made on the main
+ * thread.
+ */
+[scriptable, uuid(07b6b2f5-6d97-47b4-9584-e65bc467fe9e)]
+interface mozIStorageService : nsISupports {
+  /**
+   * Open the database with default flags in default mode.
+   */
+  const unsigned long OPEN_DEFAULT = 0;
+
+  /**
+   * Open the database with a shared cache. The shared-cache mode
+   * is more memory-efficient when many connections to the same database
+   * are expected, though, the connections will contend the cache resource.
+   * When performance matters, working without a shared-cache will
+   * improve concurrency.  @see openUnsharedDatabase
+   */
+  const unsigned long OPEN_SHARED = 1 << 0;
+
+  /**
+   * Open the underlying database in read-only mode.
+   */
+  const unsigned long OPEN_READONLY = 1 << 1;
+
+  /**
+   * Allow simultaneous access to an asynchronous read-only database
+   * without any file locking.
+   *
+   * For synchronous database, the flag has no effect.
+   *
+   * Specifying the OPEN_IGNORE_LOCKING_MODE flag will automatically
+   * turn on the OPEN_READONLY flag.
+   */
+  const unsigned long OPEN_IGNORE_LOCKING_MODE = 1 << 2;
+
+  /**
+   * All optional connection object features are off.
+   */
+  const unsigned long CONNECTION_DEFAULT = 0;
+
+  /**
+   * Enable Interrupt-method for the synchronous connection object
+   * returned by openDatabase, openSpecialDatabase, openUnsharedDatabase
+   * or openDatabaseWithFileURL calls.
+   *
+   * When this flag is not set, Interrupt-method of a
+   * synchronous connection must not be used.
+   *
+   * Asynchronous connection is always interruptible and the flag
+   * does not change anything.
+   *
+   * The following are among the potential risks side effects of
+   * calling the Interrupt-method:
+   *   - new queries started on a different thread after the
+   *     interrupt call, but before its completion, are interrupted as if
+   *     they had been running prior to the interrupt call. Thus thread
+   *     synchronization is necessary.
+   *   - calls to close the database will wait until the interruption
+   *     finishes.
+   */
+  const unsigned long CONNECTION_INTERRUPTIBLE = 1 << 0;
+
+  /**
+   * Open an asynchronous connection to a database.
+   *
+   * This method MUST be called from the main thread. The connection object
+   * returned by this function is not threadsafe. You MUST use it only from
+   * the main thread.
+   *
+   * If you have more than one connection to a file, you MUST use the EXACT
+   * SAME NAME for the file each time, including case. The sqlite code uses
+   * a simple string compare to see if there is already a connection. Opening
+   * a connection to "Foo.sqlite" and "foo.sqlite" will CORRUPT YOUR DATABASE.
+   *
+   * @param aDatabaseStore Either a nsIFile representing the file that contains
+   * the database or a special string to open a special database. The special
+   * string may be:
+   * - "memory" to open an in-memory database.
+   *
+   * @param aOpenFlags
+   *        A set of flags to open the database with optional features.
+   *        Currently supports OPEN_SHARED, OPEN_READONLY and
+   *        OPEN_IGNORE_LOCKING_MODE flags.
+   *        For full details, please refer to the documentation of the flags.
+   *
+   * @param aConnectionFlags
+   *        A set of flags to enable optional features for the returned
+   *        asynchronous connection object.
+   *        Currently supports CONNECTION_INTERRUPTIBLE flag.
+   *        For full details, please refer to the documentation of the flag.
+   *
+   * @param aCallback A callback that will receive the result of the operation.
+   *  In case of error, it may receive as status:
+   *  - NS_ERROR_OUT_OF_MEMORY if allocating a new storage object fails.
+   *  - NS_ERROR_FILE_CORRUPTED if the database file is corrupted.
+   *  In case of success, it receives as argument the new database
+   *  connection, as an instance of |mozIStorageAsyncConnection|.
+   *
+   * @throws NS_ERROR_INVALID_ARG if |aDatabaseStore| is neither a file nor
+   *         one of the special strings understood by this method, or if one of
+   *         the options passed through |aOptions| does not have
+   *         the right type.
+   * @throws NS_ERROR_NOT_SAME_THREAD if called from a thread other than the
+   *         main thread.
+   */
+  void openAsyncDatabase(in nsIVariant aDatabaseStore,
+                         in unsigned long aOpenFlags,
+                         in unsigned long aConnectionFlags,
+                         in mozIStorageCompletionCallback aCallback);
+
+  /**
+   * Get a connection to a named special database storage.
+   *
+   * @param aStorageKey a string key identifying the type of storage
+   * requested.  Valid values include: "memory".
+   *
+   * @param aName an optional string identifying the name of the database.
+   * If omitted, a filename of ":memory:" will be used which results in a
+   * private in-memory database specific to this connection, making it
+   * impossible to clone the in-memory database. If you want to be able to
+   * clone the connection (or otherwise connect to the in-memory database from
+   * a connection), then you must pick a name that's sufficiently unique within
+   * the process to not collide with other mozStorage users.
+   *
+   * @param [optional] aConnectionFlags
+   *        A set of flags to enable optional features for the returned
+   *        synchronous connection object.
+   *        Currently supports CONNECTION_INTERRUPTIBLE flag.
+   *        For full details, please refer to the documentation of the flag.
+   *
+   * @see openDatabase for restrictions on how database connections may be
+   * used. For the profile database, you should only access it from the main
+   * thread since other callers may also have connections.
+   *
+   * @returns a new mozIStorageConnection for the requested
+   * storage database.
+   *
+   * @throws NS_ERROR_INVALID_ARG if aStorageKey is invalid.
+   */
+  mozIStorageConnection openSpecialDatabase(
+      in ACString aStorageKey,
+      [optional] in ACString aName,
+      [optional] in unsigned long aConnectionFlags);
+
+  /**
+   * Open a connection to the specified file.
+   *
+   * Consumers should check mozIStorageConnection::connectionReady to ensure
+   * that they can use the database.  If this value is false, it is strongly
+   * recommended that the database be backed up with
+   * mozIStorageConnection::backupDB so user data is not lost.
+   *
+   * ==========
+   *   DANGER
+   * ==========
+   *
+   * If you have more than one connection to a file, you MUST use the EXACT
+   * SAME NAME for the file each time, including case. The sqlite code uses
+   * a simple string compare to see if there is already a connection. Opening
+   * a connection to "Foo.sqlite" and "foo.sqlite" will CORRUPT YOUR DATABASE.
+   *
+   * The connection object returned by this function is not threadsafe. You
+   * must use it only from the thread you created it from.
+   *
+   * @param aDatabaseFile
+   *        A nsIFile that represents the database that is to be opened.
+   * @param [optional] aConnectionFlags
+   *        A set of flags to enable optional features for the returned
+   *        synchronous connection object.
+   *        Currently supports CONNECTION_INTERRUPTIBLE flag.
+   *        For full details, please refer to the documentation of the flag.
+   *
+   * @returns a mozIStorageConnection for the requested database file.
+   *
+   * @throws NS_ERROR_OUT_OF_MEMORY
+   *         If allocating a new storage object fails.
+   * @throws NS_ERROR_FILE_CORRUPTED
+   *         If the database file is corrupted.
+   */
+  mozIStorageConnection openDatabase(
+      in nsIFile aDatabaseFile, [optional] in unsigned long aConnectionFlags);
+
+  /**
+   * Open a connection to the specified file that doesn't share a sqlite cache.
+   *
+   * Without a shared-cache, each connection uses its own pages cache, which
+   * may be memory inefficient with a large number of connections, in such a
+   * case so you should use openDatabase instead.  On the other side, if cache
+   * contention may be an issue, for instance when concurrency is important to
+   * ensure responsiveness, using unshared connections may be a
+   * performance win.
+   *
+   * ==========
+   *   DANGER
+   * ==========
+   *
+   * If you have more than one connection to a file, you MUST use the EXACT
+   * SAME NAME for the file each time, including case. The sqlite code uses
+   * a simple string compare to see if there is already a connection. Opening
+   * a connection to "Foo.sqlite" and "foo.sqlite" will CORRUPT YOUR DATABASE.
+   *
+   * The connection object returned by this function is not threadsafe. You
+   * must use it only from the thread you created it from.
+   *
+   * @param aDatabaseFile
+   *        A nsIFile that represents the database that is to be opened.
+   * @param [optional] aConnectionFlags
+   *        A set of flags to enable optional features for the returned
+   *        synchronous connection object.
+   *        Currently supports CONNECTION_INTERRUPTIBLE flag.
+   *        For full details, please refer to the documentation of the flag.
+   *
+   * @returns a mozIStorageConnection for the requested database file.
+   *
+   * @throws NS_ERROR_OUT_OF_MEMORY
+   *         If allocating a new storage object fails.
+   * @throws NS_ERROR_FILE_CORRUPTED
+   *         If the database file is corrupted.
+   */
+  mozIStorageConnection openUnsharedDatabase(
+      in nsIFile aDatabaseFile, [optional] in unsigned long aConnectionFlags);
+
+  /**
+   * See openDatabase(). Exactly the same only initialized with a file URL.
+   * Custom parameters can be passed to SQLite and VFS implementations through
+   * the query part of the URL.
+   *
+   * @param aURL
+   *        A nsIFileURL that represents the database that is to be opened.
+   * @param [optional] aTelemetryFilename
+   *        The name to use for the database in telemetry. Only needed if the
+   *        actual filename can contain sensitive information.
+   * @param [optional] aConnectionFlags
+   *        A set of flags to enable optional features for the returned
+   *        synchronous connection object.
+   *        Currently supports CONNECTION_INTERRUPTIBLE flag.
+   *        For full details, please refer to the documentation of the flag.
+   */
+  mozIStorageConnection openDatabaseWithFileURL(
+      in nsIFileURL aFileURL, [optional] in ACString aTelemetryFilename,
+      [optional] in unsigned long aConnectionFlags);
+};
+
+%{C++
+
+constexpr auto kMozStorageMemoryStorageKey = "memory"_ns;
+
+%}
diff --git a/storage/mozIStorageStatement.idl b/storage/mozIStorageStatement.idl
new file mode 100644
index 0000000000..ad2821bb6c
--- /dev/null
+++ b/storage/mozIStorageStatement.idl
@@ -0,0 +1,326 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 sts=2 expandtab
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozIStorageBaseStatement.idl"
+%{C++
+#include "mozilla/DebugOnly.h"
+%}
+
+[ptr] native octetPtr(uint8_t);
+
+/**
+ * A SQL statement that can be used for both synchronous and asynchronous
+ * purposes.
+ */
+[scriptable, builtinclass, uuid(5f567c35-6c32-4140-828c-683ea49cfd3a)]
+interface mozIStorageStatement : mozIStorageBaseStatement {
+  /**
+   * Create a clone of this statement, by initializing a new statement
+   * with the same connection and same SQL statement as this one.  It
+   * does not preserve statement state; that is, if a statement is
+   * being executed when it is cloned, the new statement will not be
+   * executing.
+   */
+  mozIStorageStatement clone();
+
+  /*
+   * Number of parameters
+   */
+  readonly attribute unsigned long parameterCount;
+
+  /**
+   * Name of nth parameter, if given
+   */
+  AUTF8String getParameterName(in unsigned long aParamIndex);
+
+  /**
+   * Returns the index of the named parameter.
+   *
+   * @param aName
+   *        The name of the parameter you want the index for.  This does not
+   *        include the leading ':'.
+   * @return the index of the named parameter.
+   */
+  unsigned long getParameterIndex(in AUTF8String aName);
+
+  /**
+   * Number of columns returned
+   */
+  readonly attribute unsigned long columnCount;
+
+  /**
+   * Name of nth column
+   */
+  AUTF8String getColumnName(in unsigned long aColumnIndex);
+
+  /**
+   * Obtains the index of the column with the specified name.
+   *
+   * @param aName
+   *        The name of the column.
+   * @return The index of the column with the specified name.
+   */
+  unsigned long getColumnIndex(in AUTF8String aName);
+
+  /**
+   * Reset parameters/statement execution
+   */
+  void reset();
+
+  /**
+   * Execute the query, ignoring any results.  This is accomplished by
+   * calling executeStep() once, and then calling reset().
+   *
+   * Error and last insert info, etc. are available from
+   * the mozStorageConnection.
+   */
+  void execute();
+
+  /**
+   * Execute a query, using any currently-bound parameters.  Reset
+   * must be called on the statement after the last call of
+   * executeStep.
+   *
+   * @return a boolean indicating whether there are more rows or not;
+   *         row data may be accessed using mozIStorageValueArray methods on
+   *         the statement.
+   */
+  boolean executeStep();
+
+  /**
+   * Execute a query, using any currently-bound parameters.  Reset is called
+   * when no more data is returned.  This method is only available to JavaScript
+   * consumers.
+   *
+   * @deprecated As of Mozilla 1.9.2 in favor of executeStep().
+   *
+   * @return a boolean indicating whether there are more rows or not.
+   *
+   * [deprecated] boolean step();
+   */
+
+  /**
+   * Obtains the current list of named parameters, which are settable.  This
+   * property is only available to JavaScript consumers.
+   *
+   * readonly attribute mozIStorageStatementParams params;
+   */
+
+  /**
+   * Obtains the current row, with access to all the data members by name.  This
+   * property is only available to JavaScript consumers.
+   *
+   * readonly attribute mozIStorageStatementRow row;
+   */
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// Copied contents of mozIStorageValueArray
+
+  /**
+   * These type values are returned by getTypeOfIndex
+   * to indicate what type of value is present at
+   * a given column.
+   */
+  const long VALUE_TYPE_NULL = 0;
+  const long VALUE_TYPE_INTEGER = 1;
+  const long VALUE_TYPE_FLOAT = 2;
+  const long VALUE_TYPE_TEXT = 3;
+  const long VALUE_TYPE_BLOB = 4;
+
+  /**
+   * The number of entries in the array (each corresponding to a column in the
+   * database row)
+   */
+  readonly attribute unsigned long numEntries;
+
+  /**
+   * Indicate the data type of the current result row for the the given column.
+   * SQLite will perform type conversion if you ask for a value as a different
+   * type than it is stored as.
+   *
+   * @param aIndex
+   *        0-based column index.
+   * @return The type of the value at the given column index; one of
+   *         VALUE_TYPE_NULL, VALUE_TYPE_INTEGER, VALUE_TYPE_FLOAT,
+   *         VALUE_TYPE_TEXT, VALUE_TYPE_BLOB.
+   */
+  long getTypeOfIndex(in unsigned long aIndex);
+
+  /**
+   * Retrieve the contents of a column from the current result row as a
+   * variant.
+   *
+   * @param aIndex
+   *        0-based colummn index.
+   * @return A variant with the type of the column value.
+   */
+  nsIVariant getVariant(in unsigned long aIndex);
+
+  /**
+   * Retrieve the contents of a column from the current result row as an
+   * integer.
+   *
+   * @param aIndex
+   *        0-based colummn index.
+   * @return Column value interpreted as an integer per type conversion rules.
+   * @{
+   */
+  long getInt32(in unsigned long aIndex);
+  long long getInt64(in unsigned long aIndex);
+  /** @} */
+  /**
+   * Retrieve the contents of a column from the current result row as a
+   * floating point double.
+   *
+   * @param aIndex
+   *        0-based colummn index.
+   * @return Column value interpreted as a double per type conversion rules.
+   */
+  double getDouble(in unsigned long aIndex);
+  /**
+   * Retrieve the contents of a column from the current result row as a
+   * string.
+   *
+   * @param aIndex
+   *        0-based colummn index.
+   * @return The value for the result column interpreted as a string.  If the
+   *         stored value was NULL, you will get an empty string with IsVoid set
+   *         to distinguish it from an explicitly set empty string.
+   * @{
+   */
+  AUTF8String getUTF8String(in unsigned long aIndex);
+  AString getString(in unsigned long aIndex);
+  /** @} */
+
+  /**
+   * Retrieve the contents of a column from the current result row as a
+   * blob.
+   *
+   * @param aIndex
+   *        0-based colummn index.
+   * @param[out] aDataSize
+   *             The number of bytes in the blob.
+   * @param[out] aData
+   *             The contents of the BLOB.  This will be NULL if aDataSize == 0.
+   */
+  void getBlob(in unsigned long aIndex, out unsigned long aDataSize, [array,size_is(aDataSize)] out octet aData);
+
+  /**
+   * Retrieve the contents of a Blob column from the current result row as a
+   * string.
+   *
+   * @param aIndex
+   *        0-based colummn index.
+   * @return The value for the result Blob column interpreted as a String.
+   *         No encoding conversion is performed.
+   */
+  AString getBlobAsString(in unsigned long aIndex);
+
+  /**
+   * Retrieve the contents of a Blob column from the current result row as a
+   * UTF8 string.
+   *
+   * @param aIndex
+   *        0-based colummn index.
+   * @return The value for the result Blob column interpreted as a UTF8 String.
+   *         No encoding conversion is performed.
+   */
+  AUTF8String getBlobAsUTF8String(in unsigned long aIndex);
+
+  /**
+   * Check whether the given column in the current result row is NULL.
+   *
+   * @param aIndex
+   *        0-based colummn index.
+   * @return true if the value for the result column is null.
+   */
+  boolean getIsNull(in unsigned long aIndex);
+
+  /**
+   * Returns a shared string pointer.
+   *
+   * @param aIndex
+   *        0-based colummn index.
+   * @param aByteLength
+   *        The number of bytes in the string or blob. This is the same as the
+   *        number of characters for UTF-8 strings, and twice the number of
+   *        characters for UTF-16 strings.
+   * @param aResult
+   *        A pointer to the string or blob.
+   */
+  [noscript] void getSharedUTF8String(in unsigned long aIndex, out unsigned long aByteLength, [shared,retval] out string aResult);
+  [noscript] void getSharedString(in unsigned long aIndex, out unsigned long aByteLength, [shared,retval] out wstring aResult);
+  [noscript] void getSharedBlob(in unsigned long aIndex, out unsigned long aByteLength, [shared,retval] out octetPtr aResult);
+
+  /**
+   * Getters for native code that return their values as
+   * the return type, for convenience and sanity.
+   *
+   * Not virtual; no vtable bloat.
+   */
+
+%{C++
+  inline int32_t AsInt32(uint32_t idx) {
+    int32_t v = 0;
+    mozilla::DebugOnly<nsresult> rv = GetInt32(idx, &v);
+    MOZ_ASSERT(NS_SUCCEEDED(rv) || IsNull(idx),
+               "Getting value failed, wrong column index?");
+    return v;
+  }
+
+  inline int64_t AsInt64(uint32_t idx) {
+    int64_t v = 0;
+    mozilla::DebugOnly<nsresult> rv = GetInt64(idx, &v);
+    MOZ_ASSERT(NS_SUCCEEDED(rv) || IsNull(idx),
+               "Getting value failed, wrong column index?");
+    return v;
+  }
+
+  inline double AsDouble(uint32_t idx) {
+    double v = 0.0;
+    mozilla::DebugOnly<nsresult> rv = GetDouble(idx, &v);
+    MOZ_ASSERT(NS_SUCCEEDED(rv) || IsNull(idx),
+               "Getting value failed, wrong column index?");
+    return v;
+  }
+
+  inline const char* AsSharedUTF8String(uint32_t idx, uint32_t *len) {
+    const char *str = nullptr;
+    *len = 0;
+    mozilla::DebugOnly<nsresult> rv = GetSharedUTF8String(idx, len, &str);
+    MOZ_ASSERT(NS_SUCCEEDED(rv) || IsNull(idx),
+               "Getting value failed, wrong column index?");
+    return str;
+  }
+
+  inline const char16_t* AsSharedWString(uint32_t idx, uint32_t *len) {
+    const char16_t *str = nullptr;
+    *len = 0;
+    mozilla::DebugOnly<nsresult> rv = GetSharedString(idx, len, &str);
+    MOZ_ASSERT(NS_SUCCEEDED(rv) || IsNull(idx),
+               "Getting value failed, wrong column index?");
+    return str;
+  }
+
+  inline const uint8_t* AsSharedBlob(uint32_t idx, uint32_t *len) {
+    const uint8_t *blob = nullptr;
+    *len = 0;
+    mozilla::DebugOnly<nsresult> rv = GetSharedBlob(idx, len, &blob);
+    MOZ_ASSERT(NS_SUCCEEDED(rv) || IsNull(idx),
+               "Getting value failed, wrong column index?");
+    return blob;
+  }
+
+  inline bool IsNull(uint32_t idx) {
+    bool b = false;
+    mozilla::DebugOnly<nsresult> rv = GetIsNull(idx, &b);
+    MOZ_ASSERT(NS_SUCCEEDED(rv),
+               "Getting value failed, wrong column index?");
+    return b;
+  }
+
+%}
+};
diff --git a/storage/mozIStorageStatementCallback.idl b/storage/mozIStorageStatementCallback.idl
new file mode 100644
index 0000000000..e3b888a714
--- /dev/null
+++ b/storage/mozIStorageStatementCallback.idl
@@ -0,0 +1,48 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 sts=2 expandtab
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface mozIStorageResultSet;
+interface mozIStorageError;
+
+[scriptable, uuid(29383d00-d8c4-4ddd-9f8b-c2feb0f2fcfa)]
+interface mozIStorageStatementCallback : nsISupports {
+
+  /**
+   * Called when some result is obtained from the database.  This function can
+   * be called more than once with a different storageIResultSet each time for
+   * any given asynchronous statement.
+   *
+   * @param aResultSet
+   *        The result set containing the data from the database.
+   */
+  void handleResult(in mozIStorageResultSet aResultSet);
+
+  /**
+   * Called when some error occurs while executing the statement.  This function
+   * may be called more than once with a different storageIError each time for
+   * any given asynchronous statement.
+   *
+   * @param aError
+   *        An object containing information about the error.
+   */
+  void handleError(in mozIStorageError aError);
+
+  /**
+   * Called when the statement has finished executing.  This function will only
+   * be called once for any given asynchronous statement.
+   *
+   * @param aReason
+   *        Indicates if the statement is no longer executing because it either
+   *        finished (REASON_FINISHED), was canceled (REASON_CANCELED), or
+   *        a fatal error occurred (REASON_ERROR).
+   */
+  const unsigned short REASON_FINISHED = 0;
+  const unsigned short REASON_CANCELED = 1;
+  const unsigned short REASON_ERROR = 2;
+  void handleCompletion(in unsigned short aReason);
+};
diff --git a/storage/mozIStorageVacuumParticipant.idl b/storage/mozIStorageVacuumParticipant.idl
new file mode 100644
index 0000000000..1515ac0925
--- /dev/null
+++ b/storage/mozIStorageVacuumParticipant.idl
@@ -0,0 +1,65 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface mozIStorageAsyncConnection;
+
+/**
+ * This interface contains the information that the Storage service needs to
+ * vacuum a database.  This interface is created as a service through the
+ * category manager with the category "vacuum-participant".
+ * Please see https://developer.mozilla.org/en/mozIStorageVacuumParticipant for
+ * more information.
+ */
+[scriptable, uuid(8f367508-1d9a-4d3f-be0c-ac11b6dd7dbf)]
+interface mozIStorageVacuumParticipant : nsISupports {
+  /**
+   * The expected page size in bytes for the database.  The vacuum manager will
+   * try to correct the page size by executing a full vacuum.
+   *
+   * @note If the database is using the WAL journal mode, the page size won't
+   *       be changed to the requested value.  See bug 634374.
+   * @note Valid page size values are powers of 2 between 512 and 65536.
+   *       The suggested value is mozIStorageConnection::defaultPageSize.
+   */
+  readonly attribute long expectedDatabasePageSize;
+
+  /**
+   * Whether the main schema should be using auto_vacuum = INCREMENTAL.
+   * This will cause auto_vacuum to change to INCREMENTAL if it's not set yet.
+   * It is not possible to change mode of any attached databases through this,
+   * to do that you must open a separate connection and use asyncVacuum() on it.
+   */
+  readonly attribute boolean useIncrementalVacuum;
+
+  /**
+   * Connection to the database file to be vacuumed.
+   */
+  readonly attribute mozIStorageAsyncConnection databaseConnection;
+
+  /**
+   * Notifies when a vacuum operation begins.  Listeners should avoid using the
+   * database till onEndVacuum is received.
+   *
+   * @return true to proceed with the vacuum, false if the participant wants to
+   *         opt-out for now, it will be retried later.  Useful when participant
+   *         is running some other heavy operation that can't be interrupted.
+   *
+   * @note When a vacuum operation starts or ends it will also dispatch global
+   *       "vacuum-begin" and "vacuum-end" notifications through the observer
+   *       service with the data argument being the database filename.
+   */
+  boolean onBeginVacuum();
+
+  /**
+   * Notifies when a vacuum operation ends.
+   *
+   * @param aSucceeded
+   *        reports if the vacuum succeeded or failed.
+   */
+  void onEndVacuum(in boolean aSucceeded);
+};
diff --git a/storage/mozIStorageValueArray.idl b/storage/mozIStorageValueArray.idl
new file mode 100644
index 0000000000..98eeaaf551
--- /dev/null
+++ b/storage/mozIStorageValueArray.idl
@@ -0,0 +1,154 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+%{C++
+#include "mozilla/DebugOnly.h"
+%}
+
+[ptr] native octetPtr(uint8_t);
+
+/**
+ * mozIStorageValueArray wraps an array of SQL values, such as a single database
+ * row.
+ */
+[scriptable, uuid(6e6306f4-ffa7-40f5-96ca-36159ce8f431)]
+interface mozIStorageValueArray : nsISupports {
+  /**
+   * These type values are returned by getTypeOfIndex
+   * to indicate what type of value is present at
+   * a given column.
+   */
+  const long VALUE_TYPE_NULL = 0;
+  const long VALUE_TYPE_INTEGER = 1;
+  const long VALUE_TYPE_FLOAT = 2;
+  const long VALUE_TYPE_TEXT = 3;
+  const long VALUE_TYPE_BLOB = 4;
+
+  /**
+   * numEntries
+   *
+   * number of entries in the array (each corresponding to a column
+   * in the database row)
+   */
+  readonly attribute unsigned long numEntries;
+
+  /**
+   * Returns the type of the value at the given column index;
+   * one of VALUE_TYPE_NULL, VALUE_TYPE_INTEGER, VALUE_TYPE_FLOAT,
+   * VALUE_TYPE_TEXT, VALUE_TYPE_BLOB.
+   */
+  long getTypeOfIndex(in unsigned long aIndex);
+
+  /**
+   * Obtain a value for the given entry (column) index.
+   * Due to SQLite's type conversion rules, any of these are valid
+   * for any column regardless of the column's data type.  However,
+   * if the specific type matters, getTypeOfIndex should be used
+   * first to identify the column type, and then the appropriate
+   * get method should be called.
+   *
+   * If you ask for a string value for a NULL column, you will get an empty
+   * string with IsVoid set to distinguish it from an explicitly set empty
+   * string.
+   */
+  long getInt32(in unsigned long aIndex);
+  long long getInt64(in unsigned long aIndex);
+  double getDouble(in unsigned long aIndex);
+  AUTF8String getUTF8String(in unsigned long aIndex);
+  AString getString(in unsigned long aIndex);
+
+  // data will be NULL if dataSize = 0
+  void getBlob(in unsigned long aIndex, out unsigned long aDataSize, [array,size_is(aDataSize)] out octet aData);
+  AString getBlobAsString(in unsigned long aIndex);
+  AUTF8String getBlobAsUTF8String(in unsigned long aIndex);
+  boolean getIsNull(in unsigned long aIndex);
+
+  /**
+   * Returns a shared string pointer.
+   *
+   * @param aIndex
+   *        0-based colummn index.
+   * @param aByteLength
+   *        The number of bytes in the string or blob. This is the same as the
+   *        number of characters for UTF-8 strings, and twice the number of
+   *        characters for UTF-16 strings.
+   * @param aResult
+   *        A pointer to the string or blob.
+   */
+  [noscript] void getSharedUTF8String(in unsigned long aIndex, out unsigned long aByteLength, [shared,retval] out string aResult);
+  [noscript] void getSharedString(in unsigned long aIndex, out unsigned long aByteLength, [shared,retval] out wstring aResult);
+  [noscript] void getSharedBlob(in unsigned long aIndex, out unsigned long aByteLength, [shared,retval] out octetPtr aResult);
+
+  /**
+   * Getters for native code that return their values as
+   * the return type, for convenience and sanity.
+   *
+   * Not virtual; no vtable bloat.
+   */
+
+%{C++
+  inline int32_t AsInt32(uint32_t idx) {
+    int32_t v = 0;
+    mozilla::DebugOnly<nsresult> rv = GetInt32(idx, &v);
+    MOZ_ASSERT(NS_SUCCEEDED(rv) || IsNull(idx),
+               "Getting value failed, wrong column index?");
+    return v;
+  }
+
+  inline int64_t AsInt64(uint32_t idx) {
+    int64_t v = 0;
+    mozilla::DebugOnly<nsresult> rv = GetInt64(idx, &v);
+    MOZ_ASSERT(NS_SUCCEEDED(rv) || IsNull(idx),
+               "Getting value failed, wrong column index?");
+    return v;
+  }
+
+  inline double AsDouble(uint32_t idx) {
+    double v = 0.0;
+    mozilla::DebugOnly<nsresult> rv = GetDouble(idx, &v);
+    MOZ_ASSERT(NS_SUCCEEDED(rv) || IsNull(idx),
+               "Getting value failed, wrong column index?");
+    return v;
+  }
+
+  inline const char* AsSharedUTF8String(uint32_t idx, uint32_t *len) {
+    const char *str = nullptr;
+    *len = 0;
+    mozilla::DebugOnly<nsresult> rv = GetSharedUTF8String(idx, len, &str);
+    MOZ_ASSERT(NS_SUCCEEDED(rv) || IsNull(idx),
+               "Getting value failed, wrong column index?");
+    return str;
+  }
+
+  inline const char16_t* AsSharedWString(uint32_t idx, uint32_t *len) {
+    const char16_t *str = nullptr;
+    *len = 0;
+    mozilla::DebugOnly<nsresult> rv = GetSharedString(idx, len, &str);
+    MOZ_ASSERT(NS_SUCCEEDED(rv) || IsNull(idx),
+               "Getting value failed, wrong column index?");
+    return str;
+  }
+
+  inline const uint8_t* AsSharedBlob(uint32_t idx, uint32_t *len) {
+    const uint8_t *blob = nullptr;
+    *len = 0;
+    mozilla::DebugOnly<nsresult> rv = GetSharedBlob(idx, len, &blob);
+    MOZ_ASSERT(NS_SUCCEEDED(rv) || IsNull(idx),
+               "Getting value failed, wrong column index?");
+    return blob;
+  }
+
+  inline bool IsNull(uint32_t idx) {
+    bool b = false;
+    mozilla::DebugOnly<nsresult> rv = GetIsNull(idx, &b);
+    MOZ_ASSERT(NS_SUCCEEDED(rv),
+               "Getting value failed, wrong column index?");
+    return b;
+  }
+
+%}
+
+};
diff --git a/storage/mozStorageArgValueArray.cpp b/storage/mozStorageArgValueArray.cpp
new file mode 100644
index 0000000000..56e97aaa8b
--- /dev/null
+++ b/storage/mozStorageArgValueArray.cpp
@@ -0,0 +1,182 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsError.h"
+#include "nsString.h"
+
+#include "mozStoragePrivateHelpers.h"
+#include "mozStorageArgValueArray.h"
+
+namespace mozilla {
+namespace storage {
+
+////////////////////////////////////////////////////////////////////////////////
+//// ArgValueArray
+
+ArgValueArray::ArgValueArray(int32_t aArgc, sqlite3_value** aArgv)
+    : mArgc(aArgc), mArgv(aArgv) {}
+
+NS_IMPL_ISUPPORTS(ArgValueArray, mozIStorageValueArray)
+
+////////////////////////////////////////////////////////////////////////////////
+//// mozIStorageValueArray
+
+NS_IMETHODIMP
+ArgValueArray::GetNumEntries(uint32_t* _size) {
+  *_size = mArgc;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ArgValueArray::GetTypeOfIndex(uint32_t aIndex, int32_t* _type) {
+  ENSURE_INDEX_VALUE(aIndex, mArgc);
+
+  int t = ::sqlite3_value_type(mArgv[aIndex]);
+  switch (t) {
+    case SQLITE_INTEGER:
+      *_type = VALUE_TYPE_INTEGER;
+      break;
+    case SQLITE_FLOAT:
+      *_type = VALUE_TYPE_FLOAT;
+      break;
+    case SQLITE_TEXT:
+      *_type = VALUE_TYPE_TEXT;
+      break;
+    case SQLITE_BLOB:
+      *_type = VALUE_TYPE_BLOB;
+      break;
+    case SQLITE_NULL:
+      *_type = VALUE_TYPE_NULL;
+      break;
+    default:
+      return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ArgValueArray::GetInt32(uint32_t aIndex, int32_t* _value) {
+  ENSURE_INDEX_VALUE(aIndex, mArgc);
+
+  *_value = ::sqlite3_value_int(mArgv[aIndex]);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ArgValueArray::GetInt64(uint32_t aIndex, int64_t* _value) {
+  ENSURE_INDEX_VALUE(aIndex, mArgc);
+
+  *_value = ::sqlite3_value_int64(mArgv[aIndex]);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ArgValueArray::GetDouble(uint32_t aIndex, double* _value) {
+  ENSURE_INDEX_VALUE(aIndex, mArgc);
+
+  *_value = ::sqlite3_value_double(mArgv[aIndex]);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ArgValueArray::GetUTF8String(uint32_t aIndex, nsACString& _value) {
+  ENSURE_INDEX_VALUE(aIndex, mArgc);
+
+  if (::sqlite3_value_type(mArgv[aIndex]) == SQLITE_NULL) {
+    // NULL columns should have IsVoid set to distinguish them from an empty
+    // string.
+    _value.SetIsVoid(true);
+  } else {
+    _value.Assign(
+        reinterpret_cast<const char*>(::sqlite3_value_text(mArgv[aIndex])),
+        ::sqlite3_value_bytes(mArgv[aIndex]));
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ArgValueArray::GetString(uint32_t aIndex, nsAString& _value) {
+  ENSURE_INDEX_VALUE(aIndex, mArgc);
+
+  if (::sqlite3_value_type(mArgv[aIndex]) == SQLITE_NULL) {
+    // NULL columns should have IsVoid set to distinguish them from an empty
+    // string.
+    _value.SetIsVoid(true);
+  } else {
+    const char16_t* string =
+        static_cast<const char16_t*>(::sqlite3_value_text16(mArgv[aIndex]));
+    _value.Assign(string,
+                  ::sqlite3_value_bytes16(mArgv[aIndex]) / sizeof(char16_t));
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ArgValueArray::GetBlob(uint32_t aIndex, uint32_t* _size, uint8_t** _blob) {
+  ENSURE_INDEX_VALUE(aIndex, mArgc);
+
+  int size = ::sqlite3_value_bytes(mArgv[aIndex]);
+  void* blob = moz_xmemdup(::sqlite3_value_blob(mArgv[aIndex]), size);
+  *_blob = static_cast<uint8_t*>(blob);
+  *_size = size;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ArgValueArray::GetBlobAsString(uint32_t aIndex, nsAString& aValue) {
+  return DoGetBlobAsString(this, aIndex, aValue);
+}
+
+NS_IMETHODIMP
+ArgValueArray::GetBlobAsUTF8String(uint32_t aIndex, nsACString& aValue) {
+  return DoGetBlobAsString(this, aIndex, aValue);
+}
+
+NS_IMETHODIMP
+ArgValueArray::GetIsNull(uint32_t aIndex, bool* _isNull) {
+  // GetTypeOfIndex will check aIndex for us, so we don't have to.
+  int32_t type;
+  nsresult rv = GetTypeOfIndex(aIndex, &type);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  *_isNull = (type == VALUE_TYPE_NULL);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ArgValueArray::GetSharedUTF8String(uint32_t aIndex, uint32_t* _byteLength,
+                                   const char** _string) {
+  *_string = reinterpret_cast<const char*>(::sqlite3_value_text(mArgv[aIndex]));
+  if (_byteLength) {
+    *_byteLength = ::sqlite3_value_bytes(mArgv[aIndex]);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ArgValueArray::GetSharedString(uint32_t aIndex, uint32_t* _byteLength,
+                               const char16_t** _string) {
+  *_string =
+      static_cast<const char16_t*>(::sqlite3_value_text16(mArgv[aIndex]));
+  if (_byteLength) {
+    *_byteLength = ::sqlite3_value_bytes16(mArgv[aIndex]);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ArgValueArray::GetSharedBlob(uint32_t aIndex, uint32_t* _byteLength,
+                             const uint8_t** _blob) {
+  *_blob = static_cast<const uint8_t*>(::sqlite3_value_blob(mArgv[aIndex]));
+  if (_byteLength) {
+    *_byteLength = ::sqlite3_value_bytes(mArgv[aIndex]);
+  }
+  return NS_OK;
+}
+
+}  // namespace storage
+}  // namespace mozilla
diff --git a/storage/mozStorageArgValueArray.h b/storage/mozStorageArgValueArray.h
new file mode 100644
index 0000000000..6b4c4c20e7
--- /dev/null
+++ b/storage/mozStorageArgValueArray.h
@@ -0,0 +1,35 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozStorageArgValueArray_h
+#define mozStorageArgValueArray_h
+
+#include "mozIStorageValueArray.h"
+#include "mozilla/Attributes.h"
+
+#include "sqlite3.h"
+
+namespace mozilla {
+namespace storage {
+
+class ArgValueArray final : public mozIStorageValueArray {
+ public:
+  ArgValueArray(int32_t aArgc, sqlite3_value** aArgv);
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_MOZISTORAGEVALUEARRAY
+
+ private:
+  ~ArgValueArray() {}
+
+  uint32_t mArgc;
+  sqlite3_value** mArgv;
+};
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif  // mozStorageArgValueArray_h
diff --git a/storage/mozStorageAsyncStatement.cpp b/storage/mozStorageAsyncStatement.cpp
new file mode 100644
index 0000000000..b9332f043b
--- /dev/null
+++ b/storage/mozStorageAsyncStatement.cpp
@@ -0,0 +1,338 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <limits.h>
+#include <stdio.h>
+
+#include "nsError.h"
+#include "nsProxyRelease.h"
+#include "nsThreadUtils.h"
+#include "nsIClassInfoImpl.h"
+#include "Variant.h"
+
+#include "mozStorageBindingParams.h"
+#include "mozStorageConnection.h"
+#include "mozStorageAsyncStatementJSHelper.h"
+#include "mozStorageAsyncStatementParams.h"
+#include "mozStoragePrivateHelpers.h"
+#include "mozStorageStatementRow.h"
+#include "mozStorageStatement.h"
+
+#include "mozilla/Logging.h"
+
+extern mozilla::LazyLogModule gStorageLog;
+
+namespace mozilla {
+namespace storage {
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsIClassInfo
+
+NS_IMPL_CI_INTERFACE_GETTER(AsyncStatement, mozIStorageAsyncStatement,
+                            mozIStorageBaseStatement, mozIStorageBindingParams,
+                            mozilla::storage::StorageBaseStatementInternal)
+
+class AsyncStatementClassInfo : public nsIClassInfo {
+ public:
+  constexpr AsyncStatementClassInfo() = default;
+
+  NS_DECL_ISUPPORTS_INHERITED
+
+  NS_IMETHOD
+  GetInterfaces(nsTArray<nsIID>& _array) override {
+    return NS_CI_INTERFACE_GETTER_NAME(AsyncStatement)(_array);
+  }
+
+  NS_IMETHOD
+  GetScriptableHelper(nsIXPCScriptable** _helper) override {
+    static AsyncStatementJSHelper sJSHelper;
+    *_helper = &sJSHelper;
+    return NS_OK;
+  }
+
+  NS_IMETHOD
+  GetContractID(nsACString& aContractID) override {
+    aContractID.SetIsVoid(true);
+    return NS_OK;
+  }
+
+  NS_IMETHOD
+  GetClassDescription(nsACString& aDesc) override {
+    aDesc.SetIsVoid(true);
+    return NS_OK;
+  }
+
+  NS_IMETHOD
+  GetClassID(nsCID** _id) override {
+    *_id = nullptr;
+    return NS_OK;
+  }
+
+  NS_IMETHOD
+  GetFlags(uint32_t* _flags) override {
+    *_flags = 0;
+    return NS_OK;
+  }
+
+  NS_IMETHOD
+  GetClassIDNoAlloc(nsCID* _cid) override { return NS_ERROR_NOT_AVAILABLE; }
+};
+
+NS_IMETHODIMP_(MozExternalRefCountType) AsyncStatementClassInfo::AddRef() {
+  return 2;
+}
+NS_IMETHODIMP_(MozExternalRefCountType) AsyncStatementClassInfo::Release() {
+  return 1;
+}
+NS_IMPL_QUERY_INTERFACE(AsyncStatementClassInfo, nsIClassInfo)
+
+static AsyncStatementClassInfo sAsyncStatementClassInfo;
+
+////////////////////////////////////////////////////////////////////////////////
+//// AsyncStatement
+
+AsyncStatement::AsyncStatement() : mFinalized(false) {}
+
+nsresult AsyncStatement::initialize(Connection* aDBConnection,
+                                    sqlite3* aNativeConnection,
+                                    const nsACString& aSQLStatement) {
+  MOZ_ASSERT(aDBConnection, "No database connection given!");
+  MOZ_ASSERT(aDBConnection->isConnectionReadyOnThisThread(),
+             "Database connection should be valid");
+  MOZ_ASSERT(aNativeConnection, "No native connection given!");
+
+  mDBConnection = aDBConnection;
+  mNativeConnection = aNativeConnection;
+  mSQLString = aSQLStatement;
+
+  MOZ_LOG(gStorageLog, LogLevel::Debug,
+          ("Inited async statement '%s' (0x%p)", mSQLString.get(), this));
+
+#ifdef DEBUG
+  // We want to try and test for LIKE and that consumers are using
+  // escapeStringForLIKE instead of just trusting user input.  The idea to
+  // check to see if they are binding a parameter after like instead of just
+  // using a string.  We only do this in debug builds because it's expensive!
+  auto c = nsCaseInsensitiveCStringComparator;
+  nsACString::const_iterator start, end, e;
+  aSQLStatement.BeginReading(start);
+  aSQLStatement.EndReading(end);
+  e = end;
+  while (::FindInReadable(" LIKE"_ns, start, e, c)) {
+    // We have a LIKE in here, so we perform our tests
+    // FindInReadable moves the iterator, so we have to get a new one for
+    // each test we perform.
+    nsACString::const_iterator s1, s2, s3;
+    s1 = s2 = s3 = start;
+
+    if (!(::FindInReadable(" LIKE ?"_ns, s1, end, c) ||
+          ::FindInReadable(" LIKE :"_ns, s2, end, c) ||
+          ::FindInReadable(" LIKE @"_ns, s3, end, c))) {
+      // At this point, we didn't find a LIKE statement followed by ?, :,
+      // or @, all of which are valid characters for binding a parameter.
+      // We will warn the consumer that they may not be safely using LIKE.
+      NS_WARNING(
+          "Unsafe use of LIKE detected!  Please ensure that you "
+          "are using mozIStorageAsyncStatement::escapeStringForLIKE "
+          "and that you are binding that result to the statement "
+          "to prevent SQL injection attacks.");
+    }
+
+    // resetting start and e
+    start = e;
+    e = end;
+  }
+#endif
+
+  return NS_OK;
+}
+
+mozIStorageBindingParams* AsyncStatement::getParams() {
+  nsresult rv;
+
+  // If we do not have an array object yet, make it.
+  if (!mParamsArray) {
+    nsCOMPtr<mozIStorageBindingParamsArray> array;
+    rv = NewBindingParamsArray(getter_AddRefs(array));
+    NS_ENSURE_SUCCESS(rv, nullptr);
+
+    mParamsArray = static_cast<BindingParamsArray*>(array.get());
+  }
+
+  // If there isn't already any rows added, we'll have to add one to use.
+  if (mParamsArray->length() == 0) {
+    RefPtr<AsyncBindingParams> params(new AsyncBindingParams(mParamsArray));
+    NS_ENSURE_TRUE(params, nullptr);
+
+    rv = mParamsArray->AddParams(params);
+    NS_ENSURE_SUCCESS(rv, nullptr);
+
+    // We have to unlock our params because AddParams locks them.  This is safe
+    // because no reference to the params object was, or ever will be given out.
+    params->unlock(nullptr);
+
+    // We also want to lock our array at this point - we don't want anything to
+    // be added to it.
+    mParamsArray->lock();
+  }
+
+  return *mParamsArray->begin();
+}
+
+/**
+ * If we are here then we know there are no pending async executions relying on
+ * us (StatementData holds a reference to us; this also goes for our own
+ * AsyncStatementFinalizer which proxies its release to the calling event
+ * target) and so it is always safe to destroy our sqlite3_stmt if one exists.
+ * We can be destroyed on the caller event target by
+ * garbage-collection/reference counting or on the async event target by the
+ * last execution of a statement that already lost its main-thread refs.
+ */
+AsyncStatement::~AsyncStatement() {
+  destructorAsyncFinalize();
+
+  // If we are getting destroyed on the wrong event target, proxy the connection
+  // release to the right one.
+  if (!IsOnCurrentSerialEventTarget(mDBConnection->eventTargetOpenedOn)) {
+    // NS_ProxyRelase only magic forgets for us if mDBConnection is an
+    // nsCOMPtr.  Which it is not; it's a RefPtr.
+    nsCOMPtr<nsIEventTarget> target(mDBConnection->eventTargetOpenedOn);
+    NS_ProxyRelease("AsyncStatement::mDBConnection", target,
+                    mDBConnection.forget());
+  }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsISupports
+
+NS_IMPL_ADDREF(AsyncStatement)
+NS_IMPL_RELEASE(AsyncStatement)
+
+NS_INTERFACE_MAP_BEGIN(AsyncStatement)
+  NS_INTERFACE_MAP_ENTRY(mozIStorageAsyncStatement)
+  NS_INTERFACE_MAP_ENTRY(mozIStorageBaseStatement)
+  NS_INTERFACE_MAP_ENTRY(mozIStorageBindingParams)
+  NS_INTERFACE_MAP_ENTRY(mozilla::storage::StorageBaseStatementInternal)
+  if (aIID.Equals(NS_GET_IID(nsIClassInfo))) {
+    foundInterface = static_cast<nsIClassInfo*>(&sAsyncStatementClassInfo);
+  } else
+    NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, mozIStorageAsyncStatement)
+NS_INTERFACE_MAP_END
+
+////////////////////////////////////////////////////////////////////////////////
+//// StorageBaseStatementInternal
+
+Connection* AsyncStatement::getOwner() { return mDBConnection; }
+
+int AsyncStatement::getAsyncStatement(sqlite3_stmt** _stmt) {
+#ifdef DEBUG
+  // Make sure we are never called on the connection's owning event target.
+  NS_ASSERTION(
+      !IsOnCurrentSerialEventTarget(mDBConnection->eventTargetOpenedOn),
+      "We should only be called on the async event target!");
+#endif
+
+  if (!mAsyncStatement) {
+    int rc = mDBConnection->prepareStatement(mNativeConnection, mSQLString,
+                                             &mAsyncStatement);
+    if (rc != SQLITE_OK) {
+      MOZ_LOG(gStorageLog, LogLevel::Error,
+              ("Sqlite statement prepare error: %d '%s'", rc,
+               ::sqlite3_errmsg(mNativeConnection)));
+      MOZ_LOG(gStorageLog, LogLevel::Error,
+              ("Statement was: '%s'", mSQLString.get()));
+      *_stmt = nullptr;
+      return rc;
+    }
+    MOZ_LOG(gStorageLog, LogLevel::Debug,
+            ("Initialized statement '%s' (0x%p)", mSQLString.get(),
+             mAsyncStatement));
+  }
+
+  *_stmt = mAsyncStatement;
+  return SQLITE_OK;
+}
+
+nsresult AsyncStatement::getAsynchronousStatementData(StatementData& _data) {
+  if (mFinalized) return NS_ERROR_UNEXPECTED;
+
+  // Pass null for the sqlite3_stmt; it will be requested on demand from the
+  // async event target.
+  _data = StatementData(nullptr, bindingParamsArray(), this);
+
+  return NS_OK;
+}
+
+already_AddRefed<mozIStorageBindingParams> AsyncStatement::newBindingParams(
+    mozIStorageBindingParamsArray* aOwner) {
+  if (mFinalized) return nullptr;
+
+  nsCOMPtr<mozIStorageBindingParams> params(new AsyncBindingParams(aOwner));
+  return params.forget();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// mozIStorageAsyncStatement
+
+// (nothing is specific to mozIStorageAsyncStatement)
+
+////////////////////////////////////////////////////////////////////////////////
+//// StorageBaseStatementInternal
+
+// proxy to StorageBaseStatementInternal using its define helper.
+MIXIN_IMPL_STORAGEBASESTATEMENTINTERNAL(
+    AsyncStatement, if (mFinalized) return NS_ERROR_UNEXPECTED;)
+
+NS_IMETHODIMP
+AsyncStatement::Finalize() {
+  if (mFinalized) return NS_OK;
+
+  mFinalized = true;
+
+  MOZ_LOG(gStorageLog, LogLevel::Debug,
+          ("Finalizing statement '%s'", mSQLString.get()));
+
+  asyncFinalize();
+
+  // Release the params holder, so it can release the reference to us.
+  mStatementParamsHolder = nullptr;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+AsyncStatement::BindParameters(mozIStorageBindingParamsArray* aParameters) {
+  if (mFinalized) return NS_ERROR_UNEXPECTED;
+
+  BindingParamsArray* array = static_cast<BindingParamsArray*>(aParameters);
+  if (array->getOwner() != this) return NS_ERROR_UNEXPECTED;
+
+  if (array->length() == 0) return NS_ERROR_UNEXPECTED;
+
+  mParamsArray = array;
+  mParamsArray->lock();
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+AsyncStatement::GetState(int32_t* _state) {
+  if (mFinalized)
+    *_state = MOZ_STORAGE_STATEMENT_INVALID;
+  else
+    *_state = MOZ_STORAGE_STATEMENT_READY;
+
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// mozIStorageBindingParams
+
+BOILERPLATE_BIND_PROXIES(AsyncStatement,
+                         if (mFinalized) return NS_ERROR_UNEXPECTED;)
+
+}  // namespace storage
+}  // namespace mozilla
diff --git a/storage/mozStorageAsyncStatement.h b/storage/mozStorageAsyncStatement.h
new file mode 100644
index 0000000000..ceaead1771
--- /dev/null
+++ b/storage/mozStorageAsyncStatement.h
@@ -0,0 +1,101 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_storage_mozStorageAsyncStatement_h_
+#define mozilla_storage_mozStorageAsyncStatement_h_
+
+#include "nsString.h"
+
+#include "nsTArray.h"
+
+#include "mozStorageBindingParamsArray.h"
+#include "mozStorageStatementData.h"
+#include "mozIStorageAsyncStatement.h"
+#include "StorageBaseStatementInternal.h"
+#include "mozilla/Attributes.h"
+
+namespace mozilla {
+namespace storage {
+
+class AsyncStatementJSHelper;
+class AsyncStatementParamsHolder;
+class Connection;
+
+class AsyncStatement final : public mozIStorageAsyncStatement,
+                             public StorageBaseStatementInternal {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEASYNCSTATEMENT
+  NS_DECL_MOZISTORAGEBASESTATEMENT
+  NS_DECL_MOZISTORAGEBINDINGPARAMS
+  NS_DECL_STORAGEBASESTATEMENTINTERNAL
+
+  AsyncStatement();
+
+  /**
+   * Initializes the object on aDBConnection by preparing the SQL statement
+   * given by aSQLStatement.
+   *
+   * @param aDBConnection
+   *        The Connection object this statement is associated with.
+   * @param aNativeConnection
+   *        The native Sqlite connection this statement is associated with.
+   * @param aSQLStatement
+   *        The SQL statement to prepare that this object will represent.
+   */
+  nsresult initialize(Connection* aDBConnection, sqlite3* aNativeConnection,
+                      const nsACString& aSQLStatement);
+
+  /**
+   * Obtains and transfers ownership of the array of parameters that are bound
+   * to this statment.  This can be null.
+   */
+  inline already_AddRefed<BindingParamsArray> bindingParamsArray() {
+    return mParamsArray.forget();
+  }
+
+ private:
+  ~AsyncStatement();
+
+  /**
+   * @return a pointer to the BindingParams object to use with our Bind*
+   *         method.
+   */
+  mozIStorageBindingParams* getParams();
+
+  /**
+   * The SQL string as passed by the user.  We store it because we create the
+   * async statement on-demand on the async thread.
+   */
+  nsCString mSQLString;
+
+  /**
+   * Holds the array of parameters to bind to this statement when we execute
+   * it asynchronously.
+   */
+  RefPtr<BindingParamsArray> mParamsArray;
+
+  /**
+   * Caches the JS 'params' helper for this statement.
+   */
+  nsMainThreadPtrHandle<AsyncStatementParamsHolder> mStatementParamsHolder;
+
+  /**
+   * Have we been explicitly finalized by the user?
+   */
+  bool mFinalized;
+
+  /**
+   * Required for access to private mStatementParamsHolder field by
+   * AsyncStatementJSHelper::getParams.
+   */
+  friend class AsyncStatementJSHelper;
+};
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif  // mozilla_storage_mozStorageAsyncStatement_h_
diff --git a/storage/mozStorageAsyncStatementExecution.cpp b/storage/mozStorageAsyncStatementExecution.cpp
new file mode 100644
index 0000000000..5405555de5
--- /dev/null
+++ b/storage/mozStorageAsyncStatementExecution.cpp
@@ -0,0 +1,580 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "sqlite3.h"
+
+#include "mozIStorageStatementCallback.h"
+#include "mozStorageBindingParams.h"
+#include "mozStorageHelper.h"
+#include "mozStorageResultSet.h"
+#include "mozStorageRow.h"
+#include "mozStorageConnection.h"
+#include "mozStorageError.h"
+#include "mozStoragePrivateHelpers.h"
+#include "mozStorageStatementData.h"
+#include "mozStorageAsyncStatementExecution.h"
+
+#include "mozilla/DebugOnly.h"
+#include "mozilla/Telemetry.h"
+
+#ifndef MOZ_STORAGE_SORTWARNING_SQL_DUMP
+#  include "mozilla/Logging.h"
+extern mozilla::LazyLogModule gStorageLog;
+#endif
+
+namespace mozilla {
+namespace storage {
+
+/**
+ * The following constants help batch rows into result sets.
+ * MAX_MILLISECONDS_BETWEEN_RESULTS was chosen because any user-based task that
+ * takes less than 200 milliseconds is considered to feel instantaneous to end
+ * users.  MAX_ROWS_PER_RESULT was arbitrarily chosen to reduce the number of
+ * dispatches to calling thread, while also providing reasonably-sized sets of
+ * data for consumers.  Both of these constants are used because we assume that
+ * consumers are trying to avoid blocking their execution thread for long
+ * periods of time, and dispatching many small events to the calling thread will
+ * end up blocking it.
+ */
+#define MAX_MILLISECONDS_BETWEEN_RESULTS 75
+#define MAX_ROWS_PER_RESULT 15
+
+////////////////////////////////////////////////////////////////////////////////
+//// AsyncExecuteStatements
+
+/* static */
+nsresult AsyncExecuteStatements::execute(
+    StatementDataArray&& aStatements, Connection* aConnection,
+    sqlite3* aNativeConnection, mozIStorageStatementCallback* aCallback,
+    mozIStoragePendingStatement** _stmt) {
+  // Create our event to run in the background
+  RefPtr<AsyncExecuteStatements> event = new AsyncExecuteStatements(
+      std::move(aStatements), aConnection, aNativeConnection, aCallback);
+  NS_ENSURE_TRUE(event, NS_ERROR_OUT_OF_MEMORY);
+
+  // Dispatch it to the background
+  nsIEventTarget* target = aConnection->getAsyncExecutionTarget();
+
+  // If we don't have a valid target, this is a bug somewhere else. In the past,
+  // this assert found cases where a Run method would schedule a new statement
+  // without checking if asyncClose had been called. The caller must prevent
+  // that from happening or, if the work is not critical, just avoid creating
+  // the new statement during shutdown. See bug 718449 for an example.
+  MOZ_ASSERT(target);
+  if (!target) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  nsresult rv = target->Dispatch(event, NS_DISPATCH_NORMAL);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Return it as the pending statement object and track it.
+  event.forget(_stmt);
+  return NS_OK;
+}
+
+AsyncExecuteStatements::AsyncExecuteStatements(
+    StatementDataArray&& aStatements, Connection* aConnection,
+    sqlite3* aNativeConnection, mozIStorageStatementCallback* aCallback)
+    : Runnable("AsyncExecuteStatements"),
+      mStatements(std::move(aStatements)),
+      mConnection(aConnection),
+      mNativeConnection(aNativeConnection),
+      mHasTransaction(false),
+      mCallback(aCallback),
+      mCallingThread(::do_GetCurrentThread()),
+      mMaxWait(
+          TimeDuration::FromMilliseconds(MAX_MILLISECONDS_BETWEEN_RESULTS)),
+      mIntervalStart(TimeStamp::Now()),
+      mState(PENDING),
+      mCancelRequested(false),
+      mMutex(aConnection->sharedAsyncExecutionMutex),
+      mDBMutex(aConnection->sharedDBMutex) {
+  NS_ASSERTION(mStatements.Length(), "We weren't given any statements!");
+}
+
+AsyncExecuteStatements::~AsyncExecuteStatements() {
+  MOZ_ASSERT(!mCallback, "Never called the Completion callback!");
+  MOZ_ASSERT(!mHasTransaction, "There should be no transaction at this point");
+  if (mCallback) {
+    NS_ProxyRelease("AsyncExecuteStatements::mCallback", mCallingThread,
+                    mCallback.forget());
+  }
+}
+
+bool AsyncExecuteStatements::shouldNotify() {
+#ifdef DEBUG
+  mMutex.AssertNotCurrentThreadOwns();
+
+  bool onCallingThread = false;
+  (void)mCallingThread->IsOnCurrentThread(&onCallingThread);
+  NS_ASSERTION(onCallingThread, "runEvent not running on the calling thread!");
+#endif
+
+  // We do not need to acquire mMutex here because it can only ever be written
+  // to on the calling thread, and the only thread that can call us is the
+  // calling thread, so we know that our access is serialized.
+  return !mCancelRequested;
+}
+
+bool AsyncExecuteStatements::bindExecuteAndProcessStatement(
+    StatementData& aData, bool aLastStatement) {
+  mMutex.AssertNotCurrentThreadOwns();
+
+  sqlite3_stmt* aStatement = nullptr;
+  // This cannot fail; we are only called if it's available.
+  Unused << aData.getSqliteStatement(&aStatement);
+  MOZ_DIAGNOSTIC_ASSERT(
+      aStatement,
+      "bindExecuteAndProcessStatement called without an initialized statement");
+  BindingParamsArray* paramsArray(aData);
+
+  // Iterate through all of our parameters, bind them, and execute.
+  bool continueProcessing = true;
+  BindingParamsArray::iterator itr = paramsArray->begin();
+  BindingParamsArray::iterator end = paramsArray->end();
+  while (itr != end && continueProcessing) {
+    // Bind the data to our statement.
+    nsCOMPtr<IStorageBindingParamsInternal> bindingInternal =
+        do_QueryInterface(*itr);
+    nsCOMPtr<mozIStorageError> error = bindingInternal->bind(aStatement);
+    if (error) {
+      // Set our error state.
+      mState = ERROR;
+
+      // And notify.
+      (void)notifyError(error);
+      return false;
+    }
+
+    // Advance our iterator, execute, and then process the statement.
+    itr++;
+    bool lastStatement = aLastStatement && itr == end;
+    continueProcessing = executeAndProcessStatement(aData, lastStatement);
+
+    // Always reset our statement.
+    (void)::sqlite3_reset(aStatement);
+  }
+
+  return continueProcessing;
+}
+
+bool AsyncExecuteStatements::executeAndProcessStatement(StatementData& aData,
+                                                        bool aLastStatement) {
+  mMutex.AssertNotCurrentThreadOwns();
+
+  sqlite3_stmt* aStatement = nullptr;
+  // This cannot fail; we are only called if it's available.
+  Unused << aData.getSqliteStatement(&aStatement);
+  MOZ_DIAGNOSTIC_ASSERT(
+      aStatement,
+      "executeAndProcessStatement called without an initialized statement");
+
+  // Execute our statement
+  bool hasResults;
+  do {
+    hasResults = executeStatement(aData);
+
+    // If we had an error, bail.
+    if (mState == ERROR || mState == CANCELED) return false;
+
+    // If we have been canceled, there is no point in going on...
+    {
+      MutexAutoLock lockedScope(mMutex);
+      if (mCancelRequested) {
+        mState = CANCELED;
+        return false;
+      }
+    }
+
+    // Build our result set and notify if we got anything back and have a
+    // callback to notify.
+    if (mCallback && hasResults &&
+        NS_FAILED(buildAndNotifyResults(aStatement))) {
+      // We had an error notifying, so we notify on error and stop processing.
+      mState = ERROR;
+
+      // Notify, and stop processing statements.
+      (void)notifyError(mozIStorageError::ERROR,
+                        "An error occurred while notifying about results");
+
+      return false;
+    }
+  } while (hasResults);
+
+#ifndef MOZ_STORAGE_SORTWARNING_SQL_DUMP
+  if (MOZ_LOG_TEST(gStorageLog, LogLevel::Warning))
+#endif
+  {
+    // Check to make sure that this statement was smart about what it did.
+    checkAndLogStatementPerformance(aStatement);
+  }
+
+  // If we are done, we need to set our state accordingly while we still hold
+  // our mutex.  We would have already returned if we were canceled or had
+  // an error at this point.
+  if (aLastStatement) mState = COMPLETED;
+
+  return true;
+}
+
+bool AsyncExecuteStatements::executeStatement(StatementData& aData) {
+  mMutex.AssertNotCurrentThreadOwns();
+
+  sqlite3_stmt* aStatement = nullptr;
+  // This cannot fail; we are only called if it's available.
+  Unused << aData.getSqliteStatement(&aStatement);
+  MOZ_DIAGNOSTIC_ASSERT(
+      aStatement, "executeStatement called without an initialized statement");
+
+  bool busyRetry = false;
+  while (true) {
+    if (busyRetry) {
+      busyRetry = false;
+
+      // Yield, and try again
+      Unused << PR_Sleep(PR_INTERVAL_NO_WAIT);
+
+      // Check for cancellation before retrying
+      {
+        MutexAutoLock lockedScope(mMutex);
+        if (mCancelRequested) {
+          mState = CANCELED;
+          return false;
+        }
+      }
+    }
+
+    // lock the sqlite mutex so sqlite3_errmsg cannot change
+    SQLiteMutexAutoLock lockedScope(mDBMutex);
+
+    int rc = mConnection->stepStatement(mNativeConnection, aStatement);
+
+    // Some errors are not fatal, and we can handle them and continue.
+    if (rc == SQLITE_BUSY) {
+      ::sqlite3_reset(aStatement);
+      busyRetry = true;
+      continue;
+    }
+
+    aData.MaybeRecordQueryStatus(rc);
+
+    // Stop if we have no more results.
+    if (rc == SQLITE_DONE) {
+      return false;
+    }
+
+    // If we got results, we can return now.
+    if (rc == SQLITE_ROW) {
+      return true;
+    }
+
+    if (rc == SQLITE_INTERRUPT) {
+      mState = CANCELED;
+      return false;
+    }
+
+    // Set an error state.
+    mState = ERROR;
+
+    // Construct the error message before giving up the mutex (which we cannot
+    // hold during the call to notifyError).
+    nsCOMPtr<mozIStorageError> errorObj(
+        new Error(rc, ::sqlite3_errmsg(mNativeConnection)));
+    // We cannot hold the DB mutex while calling notifyError.
+    SQLiteMutexAutoUnlock unlockedScope(mDBMutex);
+    (void)notifyError(errorObj);
+
+    // Finally, indicate that we should stop processing.
+    return false;
+  }
+}
+
+nsresult AsyncExecuteStatements::buildAndNotifyResults(
+    sqlite3_stmt* aStatement) {
+  NS_ASSERTION(mCallback, "Trying to dispatch results without a callback!");
+  mMutex.AssertNotCurrentThreadOwns();
+
+  // Build result object if we need it.
+  if (!mResultSet) mResultSet = new ResultSet();
+  NS_ENSURE_TRUE(mResultSet, NS_ERROR_OUT_OF_MEMORY);
+
+  RefPtr<Row> row(new Row());
+  NS_ENSURE_TRUE(row, NS_ERROR_OUT_OF_MEMORY);
+
+  nsresult rv = row->initialize(aStatement);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = mResultSet->add(row);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // If we have hit our maximum number of allowed results, or if we have hit
+  // the maximum amount of time we want to wait for results, notify the
+  // calling thread about it.
+  TimeStamp now = TimeStamp::Now();
+  TimeDuration delta = now - mIntervalStart;
+  if (mResultSet->rows() >= MAX_ROWS_PER_RESULT || delta > mMaxWait) {
+    // Notify the caller
+    rv = notifyResults();
+    if (NS_FAILED(rv)) return NS_OK;  // we'll try again with the next result
+
+    // Reset our start time
+    mIntervalStart = now;
+  }
+
+  return NS_OK;
+}
+
+nsresult AsyncExecuteStatements::notifyComplete() {
+  mMutex.AssertNotCurrentThreadOwns();
+  NS_ASSERTION(mState != PENDING,
+               "Still in a pending state when calling Complete!");
+
+  // Reset our statements before we try to commit or rollback.  If we are
+  // canceling and have statements that think they have pending work, the
+  // rollback will fail.
+  for (uint32_t i = 0; i < mStatements.Length(); i++) mStatements[i].reset();
+
+  // Release references to the statement data as soon as possible. If this
+  // is the last reference, statements will be finalized immediately on the
+  // async thread, hence avoiding several bounces between threads and possible
+  // race conditions with AsyncClose().
+  mStatements.Clear();
+
+  // Handle our transaction, if we have one
+  if (mHasTransaction) {
+    SQLiteMutexAutoLock lockedScope(mDBMutex);
+    if (mState == COMPLETED) {
+      nsresult rv = mConnection->commitTransactionInternal(lockedScope,
+                                                           mNativeConnection);
+      if (NS_FAILED(rv)) {
+        mState = ERROR;
+        // We cannot hold the DB mutex while calling notifyError.
+        SQLiteMutexAutoUnlock unlockedScope(mDBMutex);
+        (void)notifyError(mozIStorageError::ERROR,
+                          "Transaction failed to commit");
+      }
+    } else {
+      DebugOnly<nsresult> rv = mConnection->rollbackTransactionInternal(
+          lockedScope, mNativeConnection);
+      NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "Transaction failed to rollback");
+    }
+    mHasTransaction = false;
+  }
+
+  // This will take ownership of mCallback and make sure its destruction will
+  // happen on the owner thread.
+  Unused << mCallingThread->Dispatch(
+      NewRunnableMethod("AsyncExecuteStatements::notifyCompleteOnCallingThread",
+                        this,
+                        &AsyncExecuteStatements::notifyCompleteOnCallingThread),
+      NS_DISPATCH_NORMAL);
+
+  return NS_OK;
+}
+
+nsresult AsyncExecuteStatements::notifyCompleteOnCallingThread() {
+  MOZ_ASSERT(mCallingThread->IsOnCurrentThread());
+  // Take ownership of mCallback and responsibility for freeing it when we
+  // release it.  Any notifyResultsOnCallingThread and
+  // notifyErrorOnCallingThread calls on the stack spinning the event loop have
+  // guaranteed their safety by creating their own strong reference before
+  // invoking the callback.
+  nsCOMPtr<mozIStorageStatementCallback> callback = std::move(mCallback);
+  if (callback) {
+    Unused << callback->HandleCompletion(mState);
+  }
+  return NS_OK;
+}
+
+nsresult AsyncExecuteStatements::notifyError(int32_t aErrorCode,
+                                             const char* aMessage) {
+  mMutex.AssertNotCurrentThreadOwns();
+  mDBMutex.assertNotCurrentThreadOwns();
+
+  if (!mCallback) return NS_OK;
+
+  nsCOMPtr<mozIStorageError> errorObj(new Error(aErrorCode, aMessage));
+  NS_ENSURE_TRUE(errorObj, NS_ERROR_OUT_OF_MEMORY);
+
+  return notifyError(errorObj);
+}
+
+nsresult AsyncExecuteStatements::notifyError(mozIStorageError* aError) {
+  mMutex.AssertNotCurrentThreadOwns();
+  mDBMutex.assertNotCurrentThreadOwns();
+
+  if (!mCallback) return NS_OK;
+
+  Unused << mCallingThread->Dispatch(
+      NewRunnableMethod<nsCOMPtr<mozIStorageError>>(
+          "AsyncExecuteStatements::notifyErrorOnCallingThread", this,
+          &AsyncExecuteStatements::notifyErrorOnCallingThread, aError),
+      NS_DISPATCH_NORMAL);
+
+  return NS_OK;
+}
+
+nsresult AsyncExecuteStatements::notifyErrorOnCallingThread(
+    mozIStorageError* aError) {
+  MOZ_ASSERT(mCallingThread->IsOnCurrentThread());
+  // Acquire our own strong reference so that if the callback spins a nested
+  // event loop and notifyCompleteOnCallingThread is executed, forgetting
+  // mCallback, we still have a valid/strong reference that won't be freed until
+  // we exit.
+  nsCOMPtr<mozIStorageStatementCallback> callback = mCallback;
+  if (shouldNotify() && callback) {
+    Unused << callback->HandleError(aError);
+  }
+  return NS_OK;
+}
+
+nsresult AsyncExecuteStatements::notifyResults() {
+  mMutex.AssertNotCurrentThreadOwns();
+  MOZ_ASSERT(mCallback, "notifyResults called without a callback!");
+
+  // This takes ownership of mResultSet, a new one will be generated in
+  // buildAndNotifyResults() when further results will arrive.
+  Unused << mCallingThread->Dispatch(
+      NewRunnableMethod<RefPtr<ResultSet>>(
+          "AsyncExecuteStatements::notifyResultsOnCallingThread", this,
+          &AsyncExecuteStatements::notifyResultsOnCallingThread,
+          mResultSet.forget()),
+      NS_DISPATCH_NORMAL);
+
+  return NS_OK;
+}
+
+nsresult AsyncExecuteStatements::notifyResultsOnCallingThread(
+    ResultSet* aResultSet) {
+  MOZ_ASSERT(mCallingThread->IsOnCurrentThread());
+  // Acquire our own strong reference so that if the callback spins a nested
+  // event loop and notifyCompleteOnCallingThread is executed, forgetting
+  // mCallback, we still have a valid/strong reference that won't be freed until
+  // we exit.
+  nsCOMPtr<mozIStorageStatementCallback> callback = mCallback;
+  if (shouldNotify() && callback) {
+    Unused << callback->HandleResult(aResultSet);
+  }
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS_INHERITED(AsyncExecuteStatements, Runnable,
+                            mozIStoragePendingStatement)
+
+bool AsyncExecuteStatements::statementsNeedTransaction() {
+  // If there is more than one write statement, run in a transaction.
+  // Additionally, if we have only one statement but it needs a transaction, due
+  // to multiple BindingParams, we will wrap it in one.
+  for (uint32_t i = 0, transactionsCount = 0; i < mStatements.Length(); ++i) {
+    transactionsCount += mStatements[i].needsTransaction();
+    if (transactionsCount > 1) {
+      return true;
+    }
+  }
+  return false;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// mozIStoragePendingStatement
+
+NS_IMETHODIMP
+AsyncExecuteStatements::Cancel() {
+#ifdef DEBUG
+  bool onCallingThread = false;
+  (void)mCallingThread->IsOnCurrentThread(&onCallingThread);
+  NS_ASSERTION(onCallingThread, "Not canceling from the calling thread!");
+#endif
+
+  // If we have already canceled, we have an error, but always indicate that
+  // we are trying to cancel.
+  NS_ENSURE_FALSE(mCancelRequested, NS_ERROR_UNEXPECTED);
+
+  {
+    MutexAutoLock lockedScope(mMutex);
+
+    // We need to indicate that we want to try and cancel now.
+    mCancelRequested = true;
+  }
+
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsIRunnable
+
+NS_IMETHODIMP
+AsyncExecuteStatements::Run() {
+  MOZ_ASSERT(mConnection->isConnectionReadyOnThisThread());
+
+  // Do not run if we have been canceled.
+  {
+    MutexAutoLock lockedScope(mMutex);
+    if (mCancelRequested) mState = CANCELED;
+  }
+  if (mState == CANCELED) return notifyComplete();
+
+  if (statementsNeedTransaction()) {
+    SQLiteMutexAutoLock lockedScope(mDBMutex);
+    if (!mConnection->transactionInProgress(lockedScope)) {
+      if (NS_SUCCEEDED(mConnection->beginTransactionInternal(
+              lockedScope, mNativeConnection,
+              mozIStorageConnection::TRANSACTION_IMMEDIATE))) {
+        mHasTransaction = true;
+      }
+#ifdef DEBUG
+      else {
+        NS_WARNING("Unable to create a transaction for async execution.");
+      }
+#endif
+    }
+  }
+
+  // Execute each statement, giving the callback results if it returns any.
+  for (uint32_t i = 0; i < mStatements.Length(); i++) {
+    bool finished = (i == (mStatements.Length() - 1));
+
+    sqlite3_stmt* stmt;
+    {  // lock the sqlite mutex so sqlite3_errmsg cannot change
+      SQLiteMutexAutoLock lockedScope(mDBMutex);
+
+      int rc = mStatements[i].getSqliteStatement(&stmt);
+      if (rc != SQLITE_OK) {
+        // Set our error state.
+        mState = ERROR;
+
+        // Build the error object; can't call notifyError with the lock held
+        nsCOMPtr<mozIStorageError> errorObj(
+            new Error(rc, ::sqlite3_errmsg(mNativeConnection)));
+        {
+          // We cannot hold the DB mutex and call notifyError.
+          SQLiteMutexAutoUnlock unlockedScope(mDBMutex);
+          (void)notifyError(errorObj);
+        }
+        break;
+      }
+    }
+
+    // If we have parameters to bind, bind them, execute, and process.
+    if (mStatements[i].hasParametersToBeBound()) {
+      if (!bindExecuteAndProcessStatement(mStatements[i], finished)) break;
+    }
+    // Otherwise, just execute and process the statement.
+    else if (!executeAndProcessStatement(mStatements[i], finished)) {
+      break;
+    }
+  }
+
+  // If we still have results that we haven't notified about, take care of
+  // them now.
+  if (mResultSet) (void)notifyResults();
+
+  // Notify about completion
+  return notifyComplete();
+}
+
+}  // namespace storage
+}  // namespace mozilla
diff --git a/storage/mozStorageAsyncStatementExecution.h b/storage/mozStorageAsyncStatementExecution.h
new file mode 100644
index 0000000000..a7f35dcfbe
--- /dev/null
+++ b/storage/mozStorageAsyncStatementExecution.h
@@ -0,0 +1,243 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozStorageAsyncStatementExecution_h
+#define mozStorageAsyncStatementExecution_h
+
+#include "nscore.h"
+#include "nsTArray.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/TimeStamp.h"
+#include "mozilla/Attributes.h"
+#include "nsThreadUtils.h"
+
+#include "SQLiteMutex.h"
+#include "mozIStoragePendingStatement.h"
+#include "mozIStorageStatementCallback.h"
+#include "mozStorageHelper.h"
+
+struct sqlite3_stmt;
+
+namespace mozilla {
+namespace storage {
+
+class Connection;
+class ResultSet;
+class StatementData;
+}  // namespace storage
+}  // namespace mozilla
+
+namespace mozilla::storage {
+class AsyncExecuteStatements final : public Runnable,
+                                     public mozIStoragePendingStatement {
+ public:
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_NSIRUNNABLE
+  NS_DECL_MOZISTORAGEPENDINGSTATEMENT
+
+  /**
+   * Describes the state of execution.
+   */
+  enum ExecutionState {
+    PENDING = -1,
+    COMPLETED = mozIStorageStatementCallback::REASON_FINISHED,
+    CANCELED = mozIStorageStatementCallback::REASON_CANCELED,
+    ERROR = mozIStorageStatementCallback::REASON_ERROR
+  };
+
+  typedef nsTArray<StatementData> StatementDataArray;
+
+  /**
+   * Executes a statement in the background, and passes results back to the
+   * caller.
+   *
+   * @param aStatements
+   *        The statements to execute and possibly bind in the background.
+   *        Ownership is transfered from the caller.
+   * @param aConnection
+   *        The connection that created the statements to execute.
+   * @param aNativeConnection
+   *        The native Sqlite connection that created the statements to execute.
+   * @param aCallback
+   *        The callback that is notified of results, completion, and errors.
+   * @param _stmt
+   *        The handle to control the execution of the statements.
+   */
+  static nsresult execute(StatementDataArray&& aStatements,
+                          Connection* aConnection, sqlite3* aNativeConnection,
+                          mozIStorageStatementCallback* aCallback,
+                          mozIStoragePendingStatement** _stmt);
+
+  /**
+   * Indicates when events on the calling thread should run or not.  Certain
+   * events posted back to the calling thread should call this see if they
+   * should run or not.
+   *
+   * @pre mMutex is not held
+   *
+   * @returns true if the event should notify still, false otherwise.
+   */
+  bool shouldNotify();
+
+  /**
+   * Used by notifyComplete(), notifyError() and notifyResults() to notify on
+   * the calling thread.
+   */
+  nsresult notifyCompleteOnCallingThread();
+  nsresult notifyErrorOnCallingThread(mozIStorageError* aError);
+  nsresult notifyResultsOnCallingThread(ResultSet* aResultSet);
+
+ private:
+  AsyncExecuteStatements(StatementDataArray&& aStatements,
+                         Connection* aConnection, sqlite3* aNativeConnection,
+                         mozIStorageStatementCallback* aCallback);
+  ~AsyncExecuteStatements();
+
+  /**
+   * Binds and then executes a given statement until completion, an error
+   * occurs, or we are canceled.  If aLastStatement is true, we should set
+   * mState accordingly.
+   *
+   * @pre mMutex is not held
+   *
+   * @param aData
+   *        The StatementData to bind, execute, and then process.
+   * @param aLastStatement
+   *        Indicates if this is the last statement or not.  If it is, we have
+   *        to set the proper state.
+   * @returns true if we should continue to process statements, false otherwise.
+   */
+  bool bindExecuteAndProcessStatement(StatementData& aData,
+                                      bool aLastStatement);
+
+  /**
+   * Executes a given statement until completion, an error occurs, or we are
+   * canceled.  If aLastStatement is true, we should set mState accordingly.
+   *
+   * @pre mMutex is not held
+   *
+   * @param aData
+   *        The StatementData to execute, and then process.
+   * @param aLastStatement
+   *        Indicates if this is the last statement or not.  If it is, we have
+   *        to set the proper state.
+   * @returns true if we should continue to process statements, false otherwise.
+   */
+  bool executeAndProcessStatement(StatementData& aData, bool aLastStatement);
+
+  /**
+   * Executes a statement to completion, properly handling any error conditions.
+   *
+   * @pre mMutex is not held
+   *
+   * @param aData
+   *        The StatementData to execute to completion.
+   * @returns true if results were obtained, false otherwise.
+   */
+  bool executeStatement(StatementData& aData);
+
+  /**
+   * Builds a result set up with a row from a given statement.  If we meet the
+   * right criteria, go ahead and notify about this results too.
+   *
+   * @pre mMutex is not held
+   *
+   * @param aStatement
+   *        The statement to get the row data from.
+   */
+  nsresult buildAndNotifyResults(sqlite3_stmt* aStatement);
+
+  /**
+   * Notifies callback about completion, and does any necessary cleanup.
+   *
+   * @pre mMutex is not held
+   */
+  nsresult notifyComplete();
+
+  /**
+   * Notifies callback about an error.
+   *
+   * @pre mMutex is not held
+   * @pre mDBMutex is not held
+   *
+   * @param aErrorCode
+   *        The error code defined in mozIStorageError for the error.
+   * @param aMessage
+   *        The error string, if any.
+   * @param aError
+   *        The error object to notify the caller with.
+   */
+  nsresult notifyError(int32_t aErrorCode, const char* aMessage);
+  nsresult notifyError(mozIStorageError* aError);
+
+  /**
+   * Notifies the callback about a result set.
+   *
+   * @pre mMutex is not held
+   */
+  nsresult notifyResults();
+
+  /**
+   * Tests whether the current statements should be wrapped in an explicit
+   * transaction.
+   *
+   * @return true if an explicit transaction is needed, false otherwise.
+   */
+  bool statementsNeedTransaction();
+
+  StatementDataArray mStatements;
+  RefPtr<Connection> mConnection;
+  sqlite3* mNativeConnection;
+  bool mHasTransaction;
+  // Note, this may not be a threadsafe object - never addref/release off
+  // the calling thread.  We take a reference when this is created, and
+  // release it in the CompletionNotifier::Run() call back to this thread.
+  nsCOMPtr<mozIStorageStatementCallback> mCallback;
+  nsCOMPtr<nsIThread> mCallingThread;
+  RefPtr<ResultSet> mResultSet;
+
+  /**
+   * The maximum amount of time we want to wait between results.  Defined by
+   * MAX_MILLISECONDS_BETWEEN_RESULTS and set at construction.
+   */
+  const TimeDuration mMaxWait;
+
+  /**
+   * The start time since our last set of results.
+   */
+  TimeStamp mIntervalStart;
+
+  /**
+   * Indicates our state of execution.
+   */
+  ExecutionState mState;
+
+  /**
+   * Indicates if we should try to cancel at a cancelation point.
+   */
+  bool mCancelRequested;
+
+  /**
+   * This is the mutex that protects our state from changing between threads.
+   * This includes the following variables:
+   *   - mCancelRequested is only set on the calling thread while the lock is
+   *     held.  It is always read from within the lock on the background thread,
+   *     but not on the calling thread (see shouldNotify for why).
+   */
+  Mutex& mMutex;
+
+  /**
+   * The wrapped SQLite recursive connection mutex.  We use it whenever we call
+   * sqlite3_step and care about having reliable error messages.  By taking it
+   * prior to the call and holding it until the point where we no longer care
+   * about the error message, the user gets reliable error messages.
+   */
+  SQLiteMutex& mDBMutex;
+};
+
+}  // namespace mozilla::storage
+
+#endif  // mozStorageAsyncStatementExecution_h
diff --git a/storage/mozStorageAsyncStatementJSHelper.cpp b/storage/mozStorageAsyncStatementJSHelper.cpp
new file mode 100644
index 0000000000..73366f6604
--- /dev/null
+++ b/storage/mozStorageAsyncStatementJSHelper.cpp
@@ -0,0 +1,142 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsIXPConnect.h"
+#include "mozStorageAsyncStatement.h"
+#include "mozStorageService.h"
+
+#include "nsString.h"
+#include "nsServiceManagerUtils.h"
+
+#include "mozStorageAsyncStatementJSHelper.h"
+
+#include "mozStorageAsyncStatementParams.h"
+
+#include "jsapi.h"
+#include "js/PropertyAndElement.h"  // JS_DefineProperty, JS_DefinePropertyById
+
+#include "xpc_make_class.h"
+
+namespace mozilla {
+namespace storage {
+
+////////////////////////////////////////////////////////////////////////////////
+//// AsyncStatementJSHelper
+
+nsresult AsyncStatementJSHelper::getParams(AsyncStatement* aStatement,
+                                           JSContext* aCtx, JSObject* aScopeObj,
+                                           JS::Value* _params) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+#ifdef DEBUG
+  int32_t state;
+  (void)aStatement->GetState(&state);
+  NS_ASSERTION(state == mozIStorageAsyncStatement::MOZ_STORAGE_STATEMENT_READY,
+               "Invalid state to get the params object - all calls will fail!");
+#endif
+
+  JS::Rooted<JSObject*> scope(aCtx, aScopeObj);
+
+  if (!aStatement->mStatementParamsHolder) {
+    dom::GlobalObject global(aCtx, scope);
+    if (global.Failed()) {
+      return NS_ERROR_UNEXPECTED;
+    }
+
+    nsCOMPtr<nsPIDOMWindowInner> window =
+        do_QueryInterface(global.GetAsSupports());
+
+    RefPtr<AsyncStatementParams> params(
+        new AsyncStatementParams(window, aStatement));
+    NS_ENSURE_TRUE(params, NS_ERROR_OUT_OF_MEMORY);
+
+    RefPtr<AsyncStatementParamsHolder> paramsHolder =
+        new AsyncStatementParamsHolder(params);
+    NS_ENSURE_TRUE(paramsHolder, NS_ERROR_OUT_OF_MEMORY);
+
+    aStatement->mStatementParamsHolder =
+        new nsMainThreadPtrHolder<AsyncStatementParamsHolder>(
+            "Statement::mStatementParamsHolder", paramsHolder);
+  }
+
+  RefPtr<AsyncStatementParams> params(
+      aStatement->mStatementParamsHolder->Get());
+  JSObject* obj = params->WrapObject(aCtx, nullptr);
+  if (!obj) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  _params->setObject(*obj);
+  return NS_OK;
+}
+
+NS_IMETHODIMP_(MozExternalRefCountType) AsyncStatementJSHelper::AddRef() {
+  return 2;
+}
+NS_IMETHODIMP_(MozExternalRefCountType) AsyncStatementJSHelper::Release() {
+  return 1;
+}
+NS_INTERFACE_MAP_BEGIN(AsyncStatementJSHelper)
+  NS_INTERFACE_MAP_ENTRY(nsIXPCScriptable)
+  NS_INTERFACE_MAP_ENTRY(nsISupports)
+NS_INTERFACE_MAP_END
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsIXPCScriptable
+
+#define XPC_MAP_CLASSNAME AsyncStatementJSHelper
+#define XPC_MAP_QUOTED_CLASSNAME "AsyncStatementJSHelper"
+#define XPC_MAP_FLAGS \
+  (XPC_SCRIPTABLE_WANT_RESOLVE | XPC_SCRIPTABLE_ALLOW_PROP_MODS_DURING_RESOLVE)
+#include "xpc_map_end.h"
+
+NS_IMETHODIMP
+AsyncStatementJSHelper::Resolve(nsIXPConnectWrappedNative* aWrapper,
+                                JSContext* aCtx, JSObject* aScopeObj, jsid aId,
+                                bool* resolvedp, bool* _retval) {
+  if (!aId.isString()) return NS_OK;
+
+  // Cast to async via mozI* since direct from nsISupports is ambiguous.
+  JS::Rooted<JSObject*> scope(aCtx, aScopeObj);
+  JS::Rooted<JS::PropertyKey> id(aCtx, aId);
+  mozIStorageAsyncStatement* iAsyncStmt =
+      static_cast<mozIStorageAsyncStatement*>(aWrapper->Native());
+  AsyncStatement* stmt = static_cast<AsyncStatement*>(iAsyncStmt);
+
+#ifdef DEBUG
+  {
+    nsISupports* supp = aWrapper->Native();
+    nsCOMPtr<mozIStorageAsyncStatement> isStatement(do_QueryInterface(supp));
+    NS_ASSERTION(isStatement, "How is this not an async statement?!");
+  }
+#endif
+
+  if (::JS_LinearStringEqualsLiteral(id.toLinearString(), "params")) {
+    JS::Rooted<JS::Value> val(aCtx);
+    nsresult rv = getParams(stmt, aCtx, scope, val.address());
+    NS_ENSURE_SUCCESS(rv, rv);
+    *_retval = ::JS_DefinePropertyById(aCtx, scope, id, val, JSPROP_RESOLVING);
+    *resolvedp = true;
+    return NS_OK;
+  }
+
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// AsyncStatementParamsHolder
+
+NS_IMPL_ISUPPORTS0(AsyncStatementParamsHolder);
+
+AsyncStatementParamsHolder::~AsyncStatementParamsHolder() {
+  MOZ_ASSERT(NS_IsMainThread());
+  // We are considered dead at this point, so any wrappers for row or params
+  // need to lose their reference to the statement.
+  mParams->mStatement = nullptr;
+}
+
+}  // namespace storage
+}  // namespace mozilla
diff --git a/storage/mozStorageAsyncStatementJSHelper.h b/storage/mozStorageAsyncStatementJSHelper.h
new file mode 100644
index 0000000000..ee787fca0b
--- /dev/null
+++ b/storage/mozStorageAsyncStatementJSHelper.h
@@ -0,0 +1,58 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_storage_mozStorageAsyncStatementJSHelper_h_
+#define mozilla_storage_mozStorageAsyncStatementJSHelper_h_
+
+#include "nsIXPCScriptable.h"
+
+namespace mozilla {
+namespace storage {
+
+class AsyncStatement;
+class AsyncStatementParams;
+
+/**
+ * A modified version of StatementJSHelper that only exposes the async-specific
+ * 'params' helper.  We do not expose 'row' or 'step' as they do not apply to
+ * us.
+ */
+class AsyncStatementJSHelper : public nsIXPCScriptable {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIXPCSCRIPTABLE
+
+ private:
+  nsresult getParams(AsyncStatement*, JSContext*, JSObject*, JS::Value*);
+};
+
+/**
+ * Wrapper used to clean up the references JS helpers hold to the statement.
+ * For cycle-avoidance reasons they do not hold reference-counted references,
+ * so it is important we do this.
+ */
+class AsyncStatementParamsHolder final : public nsISupports {
+ public:
+  NS_DECL_ISUPPORTS
+
+  explicit AsyncStatementParamsHolder(AsyncStatementParams* aParams)
+      : mParams(aParams) {}
+
+  AsyncStatementParams* Get() const {
+    MOZ_ASSERT(mParams);
+    return mParams;
+  }
+
+ private:
+  virtual ~AsyncStatementParamsHolder();
+
+  RefPtr<AsyncStatementParams> mParams;
+};
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif  // mozilla_storage_mozStorageAsyncStatementJSHelper_h_
diff --git a/storage/mozStorageAsyncStatementParams.cpp b/storage/mozStorageAsyncStatementParams.cpp
new file mode 100644
index 0000000000..cb8601504e
--- /dev/null
+++ b/storage/mozStorageAsyncStatementParams.cpp
@@ -0,0 +1,116 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozStorageAsyncStatementParams.h"
+
+#include "nsJSUtils.h"
+#include "nsString.h"
+
+#include "jsapi.h"
+
+#include "mozilla/ErrorResult.h"
+#include "mozilla/dom/MozStorageAsyncStatementParamsBinding.h"
+#include "mozStorageAsyncStatement.h"
+#include "mozStoragePrivateHelpers.h"
+
+namespace mozilla {
+namespace storage {
+
+////////////////////////////////////////////////////////////////////////////////
+//// AsyncStatementParams
+
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(AsyncStatementParams, mWindow)
+
+NS_INTERFACE_TABLE_HEAD(AsyncStatementParams)
+  NS_WRAPPERCACHE_INTERFACE_TABLE_ENTRY
+  NS_INTERFACE_TABLE(AsyncStatementParams, nsISupports)
+  NS_INTERFACE_TABLE_TO_MAP_SEGUE_CYCLE_COLLECTION(AsyncStatementParams)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(AsyncStatementParams)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(AsyncStatementParams)
+
+AsyncStatementParams::AsyncStatementParams(nsPIDOMWindowInner* aWindow,
+                                           AsyncStatement* aStatement)
+    : mWindow(aWindow), mStatement(aStatement) {
+  NS_ASSERTION(mStatement != nullptr, "mStatement is null");
+}
+
+JSObject* AsyncStatementParams::WrapObject(JSContext* aCx,
+                                           JS::Handle<JSObject*> aGivenProto) {
+  return dom::MozStorageAsyncStatementParams_Binding::Wrap(aCx, this,
+                                                           aGivenProto);
+}
+
+void AsyncStatementParams::NamedGetter(JSContext* aCx, const nsAString& aName,
+                                       bool& aFound,
+                                       JS::MutableHandle<JS::Value> aResult,
+                                       mozilla::ErrorResult& aRv) {
+  if (!mStatement) {
+    aRv.Throw(NS_ERROR_NOT_INITIALIZED);
+    return;
+  }
+
+  // Unfortunately there's no API that lets us return the parameter value.
+  aFound = false;
+}
+
+void AsyncStatementParams::NamedSetter(JSContext* aCx, const nsAString& aName,
+                                       JS::Handle<JS::Value> aValue,
+                                       mozilla::ErrorResult& aRv) {
+  if (!mStatement) {
+    aRv.Throw(NS_ERROR_NOT_INITIALIZED);
+    return;
+  }
+
+  NS_ConvertUTF16toUTF8 name(aName);
+
+  nsCOMPtr<nsIVariant> variant(convertJSValToVariant(aCx, aValue));
+  if (!variant) {
+    aRv.Throw(NS_ERROR_UNEXPECTED);
+    return;
+  }
+
+  aRv = mStatement->BindByName(name, variant);
+}
+
+void AsyncStatementParams::GetSupportedNames(nsTArray<nsString>& aNames) {
+  // We don't know how many params there are, so we can't implement this for
+  // AsyncStatementParams.
+}
+
+void AsyncStatementParams::IndexedGetter(JSContext* aCx, uint32_t aIndex,
+                                         bool& aFound,
+                                         JS::MutableHandle<JS::Value> aResult,
+                                         mozilla::ErrorResult& aRv) {
+  if (!mStatement) {
+    aRv.Throw(NS_ERROR_NOT_INITIALIZED);
+    return;
+  }
+
+  // Unfortunately there's no API that lets us return the parameter value.
+  aFound = false;
+}
+
+void AsyncStatementParams::IndexedSetter(JSContext* aCx, uint32_t aIndex,
+                                         JS::Handle<JS::Value> aValue,
+                                         mozilla::ErrorResult& aRv) {
+  if (!mStatement) {
+    aRv.Throw(NS_ERROR_NOT_INITIALIZED);
+    return;
+  }
+
+  nsCOMPtr<nsIVariant> variant(convertJSValToVariant(aCx, aValue));
+  if (!variant) {
+    aRv.Throw(NS_ERROR_UNEXPECTED);
+    return;
+  }
+
+  aRv = mStatement->BindByIndex(aIndex, variant);
+}
+
+}  // namespace storage
+}  // namespace mozilla
diff --git a/storage/mozStorageAsyncStatementParams.h b/storage/mozStorageAsyncStatementParams.h
new file mode 100644
index 0000000000..c72afc2bc3
--- /dev/null
+++ b/storage/mozStorageAsyncStatementParams.h
@@ -0,0 +1,69 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_storage_mozStorageAsyncStatementParams_h_
+#define mozilla_storage_mozStorageAsyncStatementParams_h_
+
+#include "mozilla/Attributes.h"
+#include "nsPIDOMWindow.h"
+#include "nsWrapperCache.h"
+
+namespace mozilla {
+class ErrorResult;
+
+namespace storage {
+
+class AsyncStatement;
+
+class AsyncStatementParams final : public nsISupports, public nsWrapperCache {
+ public:
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS(AsyncStatementParams)
+
+  explicit AsyncStatementParams(nsPIDOMWindowInner* aWindow,
+                                AsyncStatement* aStatement);
+
+  void NamedGetter(JSContext* aCx, const nsAString& aName, bool& aFound,
+                   JS::MutableHandle<JS::Value> aResult,
+                   mozilla::ErrorResult& aRv);
+
+  void NamedSetter(JSContext* aCx, const nsAString& aName,
+                   JS::Handle<JS::Value> aValue, mozilla::ErrorResult& aRv);
+
+  uint32_t Length() const {
+    // WebIDL requires a .length property when there's an indexed getter.
+    // Unfortunately we don't know how many params there are in the async case,
+    // so we have to lie.
+    return UINT16_MAX;
+  }
+
+  void IndexedGetter(JSContext* aCx, uint32_t aIndex, bool& aFound,
+                     JS::MutableHandle<JS::Value> aResult,
+                     mozilla::ErrorResult& aRv);
+
+  void IndexedSetter(JSContext* aCx, uint32_t aIndex,
+                     JS::Handle<JS::Value> aValue, mozilla::ErrorResult& aRv);
+
+  void GetSupportedNames(nsTArray<nsString>& aNames);
+
+  JSObject* WrapObject(JSContext* aCx,
+                       JS::Handle<JSObject*> aGivenProto) override;
+
+  nsPIDOMWindowInner* GetParentObject() const { return mWindow; }
+
+ private:
+  virtual ~AsyncStatementParams() {}
+
+  nsCOMPtr<nsPIDOMWindowInner> mWindow;
+  AsyncStatement* mStatement;
+
+  friend class AsyncStatementParamsHolder;
+};
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif  // mozilla_storage_mozStorageAsyncStatementParams_h_
diff --git a/storage/mozStorageBindingParams.cpp b/storage/mozStorageBindingParams.cpp
new file mode 100644
index 0000000000..1cd50c7a6f
--- /dev/null
+++ b/storage/mozStorageBindingParams.cpp
@@ -0,0 +1,431 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <limits.h>
+
+#include "mozilla/UniquePtrExtensions.h"
+#include "nsString.h"
+
+#include "mozStorageError.h"
+#include "mozStoragePrivateHelpers.h"
+#include "mozStorageBindingParams.h"
+#include "Variant.h"
+
+namespace mozilla::storage {
+
+////////////////////////////////////////////////////////////////////////////////
+//// Local Helper Objects
+
+namespace {
+
+struct BindingColumnData {
+  BindingColumnData(sqlite3_stmt* aStmt, int aColumn)
+      : stmt(aStmt), column(aColumn) {}
+  sqlite3_stmt* stmt;
+  int column;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Variant Specialization Functions (variantToSQLiteT)
+
+int sqlite3_T_int(BindingColumnData aData, int aValue) {
+  return ::sqlite3_bind_int(aData.stmt, aData.column + 1, aValue);
+}
+
+int sqlite3_T_int64(BindingColumnData aData, sqlite3_int64 aValue) {
+  return ::sqlite3_bind_int64(aData.stmt, aData.column + 1, aValue);
+}
+
+int sqlite3_T_double(BindingColumnData aData, double aValue) {
+  return ::sqlite3_bind_double(aData.stmt, aData.column + 1, aValue);
+}
+
+int sqlite3_T_text(BindingColumnData aData, const nsCString& aValue) {
+  return ::sqlite3_bind_text(aData.stmt, aData.column + 1, aValue.get(),
+                             aValue.Length(), SQLITE_TRANSIENT);
+}
+
+int sqlite3_T_text16(BindingColumnData aData, const nsString& aValue) {
+  return ::sqlite3_bind_text16(
+      aData.stmt, aData.column + 1, aValue.get(),
+      aValue.Length() * sizeof(char16_t),  // Length in bytes!
+      SQLITE_TRANSIENT);
+}
+
+int sqlite3_T_null(BindingColumnData aData) {
+  return ::sqlite3_bind_null(aData.stmt, aData.column + 1);
+}
+
+int sqlite3_T_blob(BindingColumnData aData, const void* aBlob, int aSize) {
+  return ::sqlite3_bind_blob(aData.stmt, aData.column + 1, aBlob, aSize, free);
+}
+
+#include "variantToSQLiteT_impl.h"
+
+}  // namespace
+
+////////////////////////////////////////////////////////////////////////////////
+//// BindingParams
+
+BindingParams::BindingParams(mozIStorageBindingParamsArray* aOwningArray,
+                             Statement* aOwningStatement)
+    : mLocked(false),
+      mOwningArray(aOwningArray),
+      mOwningStatement(aOwningStatement),
+      mParamCount(0) {
+  (void)mOwningStatement->GetParameterCount(&mParamCount);
+  mParameters.SetCapacity(mParamCount);
+}
+
+BindingParams::BindingParams(mozIStorageBindingParamsArray* aOwningArray)
+    : mLocked(false),
+      mOwningArray(aOwningArray),
+      mOwningStatement(nullptr),
+      mParamCount(0) {}
+
+AsyncBindingParams::AsyncBindingParams(
+    mozIStorageBindingParamsArray* aOwningArray)
+    : BindingParams(aOwningArray) {}
+
+void BindingParams::lock() {
+  NS_ASSERTION(mLocked == false, "Parameters have already been locked!");
+  mLocked = true;
+
+  // We no longer need to hold a reference to our statement or our owning array.
+  // The array owns us at this point, and it will own a reference to the
+  // statement.
+  mOwningStatement = nullptr;
+  mOwningArray = nullptr;
+}
+
+void BindingParams::unlock(Statement* aOwningStatement) {
+  NS_ASSERTION(mLocked == true, "Parameters were not yet locked!");
+  mLocked = false;
+  mOwningStatement = aOwningStatement;
+}
+
+const mozIStorageBindingParamsArray* BindingParams::getOwner() const {
+  return mOwningArray;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsISupports
+
+NS_IMPL_ISUPPORTS(BindingParams, mozIStorageBindingParams,
+                  IStorageBindingParamsInternal)
+
+////////////////////////////////////////////////////////////////////////////////
+//// IStorageBindingParamsInternal
+
+already_AddRefed<mozIStorageError> BindingParams::bind(
+    sqlite3_stmt* aStatement) {
+  // Iterate through all of our stored data, and bind it.
+  for (size_t i = 0; i < mParameters.Length(); i++) {
+    int rc = variantToSQLiteT(BindingColumnData(aStatement, i), mParameters[i]);
+    if (rc != SQLITE_OK) {
+      // We had an error while trying to bind.  Now we need to create an error
+      // object with the right message.  Note that we special case
+      // SQLITE_MISMATCH, but otherwise get the message from SQLite.
+      const char* msg = "Could not covert nsIVariant to SQLite type.";
+      if (rc != SQLITE_MISMATCH)
+        msg = ::sqlite3_errmsg(::sqlite3_db_handle(aStatement));
+
+      nsCOMPtr<mozIStorageError> err(new Error(rc, msg));
+      return err.forget();
+    }
+  }
+
+  return nullptr;
+}
+
+already_AddRefed<mozIStorageError> AsyncBindingParams::bind(
+    sqlite3_stmt* aStatement) {
+  // We should bind by index using the super-class if there is nothing in our
+  // hashtable.
+  if (!mNamedParameters.Count()) return BindingParams::bind(aStatement);
+
+  nsCOMPtr<mozIStorageError> err;
+
+  for (const auto& entry : mNamedParameters) {
+    const nsACString& key = entry.GetKey();
+
+    // We do not accept any forms of names other than ":name", but we need to
+    // add the colon for SQLite.
+    nsAutoCString name(":");
+    name.Append(key);
+    int oneIdx = ::sqlite3_bind_parameter_index(aStatement, name.get());
+
+    if (oneIdx == 0) {
+      nsAutoCString errMsg(key);
+      errMsg.AppendLiteral(" is not a valid named parameter.");
+      err = new Error(SQLITE_RANGE, errMsg.get());
+      break;
+    }
+
+    // XPCVariant's AddRef and Release are not thread-safe and so we must not
+    // do anything that would invoke them here on the async thread.  As such we
+    // can't cram aValue into mParameters using ReplaceObjectAt so that
+    // we can freeload off of the BindingParams::Bind implementation.
+    int rc = variantToSQLiteT(BindingColumnData(aStatement, oneIdx - 1),
+                              entry.GetWeak());
+    if (rc != SQLITE_OK) {
+      // We had an error while trying to bind.  Now we need to create an error
+      // object with the right message.  Note that we special case
+      // SQLITE_MISMATCH, but otherwise get the message from SQLite.
+      const char* msg = "Could not covert nsIVariant to SQLite type.";
+      if (rc != SQLITE_MISMATCH) {
+        msg = ::sqlite3_errmsg(::sqlite3_db_handle(aStatement));
+      }
+      err = new Error(rc, msg);
+      break;
+    }
+  }
+
+  return err.forget();
+}
+
+///////////////////////////////////////////////////////////////////////////////
+//// mozIStorageBindingParams
+
+NS_IMETHODIMP
+BindingParams::BindByName(const nsACString& aName, nsIVariant* aValue) {
+  NS_ENSURE_FALSE(mLocked, NS_ERROR_UNEXPECTED);
+
+  // Get the column index that we need to store this at.
+  uint32_t index;
+  nsresult rv = mOwningStatement->GetParameterIndex(aName, &index);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return BindByIndex(index, aValue);
+}
+
+NS_IMETHODIMP
+AsyncBindingParams::BindByName(const nsACString& aName, nsIVariant* aValue) {
+  NS_ENSURE_FALSE(mLocked, NS_ERROR_UNEXPECTED);
+
+  RefPtr<Variant_base> variant = convertVariantToStorageVariant(aValue);
+  if (!variant) return NS_ERROR_UNEXPECTED;
+
+  mNamedParameters.InsertOrUpdate(aName, nsCOMPtr<nsIVariant>{variant});
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+BindingParams::BindUTF8StringByName(const nsACString& aName,
+                                    const nsACString& aValue) {
+  nsCOMPtr<nsIVariant> value(new UTF8TextVariant(aValue));
+  NS_ENSURE_TRUE(value, NS_ERROR_OUT_OF_MEMORY);
+
+  return BindByName(aName, value);
+}
+
+NS_IMETHODIMP
+BindingParams::BindStringByName(const nsACString& aName,
+                                const nsAString& aValue) {
+  nsCOMPtr<nsIVariant> value(new TextVariant(aValue));
+  NS_ENSURE_TRUE(value, NS_ERROR_OUT_OF_MEMORY);
+
+  return BindByName(aName, value);
+}
+
+NS_IMETHODIMP
+BindingParams::BindDoubleByName(const nsACString& aName, double aValue) {
+  nsCOMPtr<nsIVariant> value(new FloatVariant(aValue));
+  NS_ENSURE_TRUE(value, NS_ERROR_OUT_OF_MEMORY);
+
+  return BindByName(aName, value);
+}
+
+NS_IMETHODIMP
+BindingParams::BindInt32ByName(const nsACString& aName, int32_t aValue) {
+  nsCOMPtr<nsIVariant> value(new IntegerVariant(aValue));
+  NS_ENSURE_TRUE(value, NS_ERROR_OUT_OF_MEMORY);
+
+  return BindByName(aName, value);
+}
+
+NS_IMETHODIMP
+BindingParams::BindInt64ByName(const nsACString& aName, int64_t aValue) {
+  nsCOMPtr<nsIVariant> value(new IntegerVariant(aValue));
+  NS_ENSURE_TRUE(value, NS_ERROR_OUT_OF_MEMORY);
+
+  return BindByName(aName, value);
+}
+
+NS_IMETHODIMP
+BindingParams::BindNullByName(const nsACString& aName) {
+  nsCOMPtr<nsIVariant> value(new NullVariant());
+  NS_ENSURE_TRUE(value, NS_ERROR_OUT_OF_MEMORY);
+
+  return BindByName(aName, value);
+}
+
+NS_IMETHODIMP
+BindingParams::BindBlobByName(const nsACString& aName, const uint8_t* aValue,
+                              uint32_t aValueSize) {
+  NS_ENSURE_ARG_MAX(aValueSize, INT_MAX);
+  std::pair<const void*, int> data(static_cast<const void*>(aValue),
+                                   int(aValueSize));
+  nsCOMPtr<nsIVariant> value(new BlobVariant(data));
+  NS_ENSURE_TRUE(value, NS_ERROR_OUT_OF_MEMORY);
+
+  return BindByName(aName, value);
+}
+
+NS_IMETHODIMP
+BindingParams::BindBlobArrayByName(const nsACString& aName,
+                                   const nsTArray<uint8_t>& aValue) {
+  return BindBlobByName(aName, aValue.Elements(), aValue.Length());
+}
+
+NS_IMETHODIMP
+BindingParams::BindStringAsBlobByName(const nsACString& aName,
+                                      const nsAString& aValue) {
+  return DoBindStringAsBlobByName(this, aName, aValue);
+}
+
+NS_IMETHODIMP
+BindingParams::BindUTF8StringAsBlobByName(const nsACString& aName,
+                                          const nsACString& aValue) {
+  return DoBindStringAsBlobByName(this, aName, aValue);
+}
+
+NS_IMETHODIMP
+BindingParams::BindAdoptedBlobByName(const nsACString& aName, uint8_t* aValue,
+                                     uint32_t aValueSize) {
+  UniqueFreePtr<uint8_t> uniqueValue(aValue);
+  NS_ENSURE_ARG_MAX(aValueSize, INT_MAX);
+  std::pair<uint8_t*, int> data(uniqueValue.release(), int(aValueSize));
+  nsCOMPtr<nsIVariant> value(new AdoptedBlobVariant(data));
+
+  return BindByName(aName, value);
+}
+
+NS_IMETHODIMP
+BindingParams::BindByIndex(uint32_t aIndex, nsIVariant* aValue) {
+  NS_ENSURE_FALSE(mLocked, NS_ERROR_UNEXPECTED);
+  ENSURE_INDEX_VALUE(aIndex, mParamCount);
+
+  // Store the variant for later use.
+  RefPtr<Variant_base> variant = convertVariantToStorageVariant(aValue);
+  if (!variant) return NS_ERROR_UNEXPECTED;
+  if (mParameters.Length() <= aIndex) {
+    (void)mParameters.SetLength(aIndex);
+    (void)mParameters.AppendElement(variant);
+  } else {
+    mParameters.ReplaceElementAt(aIndex, variant);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+AsyncBindingParams::BindByIndex(uint32_t aIndex, nsIVariant* aValue) {
+  NS_ENSURE_FALSE(mLocked, NS_ERROR_UNEXPECTED);
+  // In the asynchronous case we do not know how many parameters there are to
+  // bind to, so we cannot check the validity of aIndex.
+
+  RefPtr<Variant_base> variant = convertVariantToStorageVariant(aValue);
+  if (!variant) return NS_ERROR_UNEXPECTED;
+  if (mParameters.Length() <= aIndex) {
+    mParameters.SetLength(aIndex);
+    mParameters.AppendElement(variant);
+  } else {
+    mParameters.ReplaceElementAt(aIndex, variant);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+BindingParams::BindUTF8StringByIndex(uint32_t aIndex,
+                                     const nsACString& aValue) {
+  nsCOMPtr<nsIVariant> value(new UTF8TextVariant(aValue));
+  NS_ENSURE_TRUE(value, NS_ERROR_OUT_OF_MEMORY);
+
+  return BindByIndex(aIndex, value);
+}
+
+NS_IMETHODIMP
+BindingParams::BindStringByIndex(uint32_t aIndex, const nsAString& aValue) {
+  nsCOMPtr<nsIVariant> value(new TextVariant(aValue));
+  NS_ENSURE_TRUE(value, NS_ERROR_OUT_OF_MEMORY);
+
+  return BindByIndex(aIndex, value);
+}
+
+NS_IMETHODIMP
+BindingParams::BindDoubleByIndex(uint32_t aIndex, double aValue) {
+  nsCOMPtr<nsIVariant> value(new FloatVariant(aValue));
+  NS_ENSURE_TRUE(value, NS_ERROR_OUT_OF_MEMORY);
+
+  return BindByIndex(aIndex, value);
+}
+
+NS_IMETHODIMP
+BindingParams::BindInt32ByIndex(uint32_t aIndex, int32_t aValue) {
+  nsCOMPtr<nsIVariant> value(new IntegerVariant(aValue));
+  NS_ENSURE_TRUE(value, NS_ERROR_OUT_OF_MEMORY);
+
+  return BindByIndex(aIndex, value);
+}
+
+NS_IMETHODIMP
+BindingParams::BindInt64ByIndex(uint32_t aIndex, int64_t aValue) {
+  nsCOMPtr<nsIVariant> value(new IntegerVariant(aValue));
+  NS_ENSURE_TRUE(value, NS_ERROR_OUT_OF_MEMORY);
+
+  return BindByIndex(aIndex, value);
+}
+
+NS_IMETHODIMP
+BindingParams::BindNullByIndex(uint32_t aIndex) {
+  nsCOMPtr<nsIVariant> value(new NullVariant());
+  NS_ENSURE_TRUE(value, NS_ERROR_OUT_OF_MEMORY);
+
+  return BindByIndex(aIndex, value);
+}
+
+NS_IMETHODIMP
+BindingParams::BindBlobByIndex(uint32_t aIndex, const uint8_t* aValue,
+                               uint32_t aValueSize) {
+  NS_ENSURE_ARG_MAX(aValueSize, INT_MAX);
+  std::pair<const void*, int> data(static_cast<const void*>(aValue),
+                                   int(aValueSize));
+  nsCOMPtr<nsIVariant> value(new BlobVariant(data));
+  NS_ENSURE_TRUE(value, NS_ERROR_OUT_OF_MEMORY);
+
+  return BindByIndex(aIndex, value);
+}
+
+NS_IMETHODIMP
+BindingParams::BindBlobArrayByIndex(uint32_t aIndex,
+                                    const nsTArray<uint8_t>& aValue) {
+  return BindBlobByIndex(aIndex, aValue.Elements(), aValue.Length());
+}
+
+NS_IMETHODIMP
+BindingParams::BindStringAsBlobByIndex(uint32_t aIndex,
+                                       const nsAString& aValue) {
+  return DoBindStringAsBlobByIndex(this, aIndex, aValue);
+}
+
+NS_IMETHODIMP
+BindingParams::BindUTF8StringAsBlobByIndex(uint32_t aIndex,
+                                           const nsACString& aValue) {
+  return DoBindStringAsBlobByIndex(this, aIndex, aValue);
+}
+
+NS_IMETHODIMP
+BindingParams::BindAdoptedBlobByIndex(uint32_t aIndex, uint8_t* aValue,
+                                      uint32_t aValueSize) {
+  UniqueFreePtr<uint8_t> uniqueValue(aValue);
+  NS_ENSURE_ARG_MAX(aValueSize, INT_MAX);
+  std::pair<uint8_t*, int> data(uniqueValue.release(), int(aValueSize));
+  nsCOMPtr<nsIVariant> value(new AdoptedBlobVariant(data));
+
+  return BindByIndex(aIndex, value);
+}
+
+}  // namespace mozilla::storage
diff --git a/storage/mozStorageBindingParams.h b/storage/mozStorageBindingParams.h
new file mode 100644
index 0000000000..cef221ecef
--- /dev/null
+++ b/storage/mozStorageBindingParams.h
@@ -0,0 +1,111 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozStorageBindingParams_h
+#define mozStorageBindingParams_h
+
+#include "nsCOMArray.h"
+#include "nsIVariant.h"
+#include "nsInterfaceHashtable.h"
+
+#include "mozStorageBindingParamsArray.h"
+#include "mozStorageStatement.h"
+#include "mozStorageAsyncStatement.h"
+#include "Variant.h"
+
+#include "mozIStorageBindingParams.h"
+#include "IStorageBindingParamsInternal.h"
+
+namespace mozilla {
+namespace storage {
+
+class BindingParams : public mozIStorageBindingParams,
+                      public IStorageBindingParamsInternal {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEBINDINGPARAMS
+  NS_DECL_ISTORAGEBINDINGPARAMSINTERNAL
+
+  /**
+   * Locks the parameters and prevents further modification to it (such as
+   * binding more elements to it).
+   */
+  void lock();
+
+  /**
+   * Unlocks the parameters and allows modification to it again.
+   *
+   * @param aOwningStatement
+   *        The statement that owns us.  We cleared this when we were locked,
+   *        and our invariant requires us to have this, so you need to tell us
+   *        again.
+   */
+  void unlock(Statement* aOwningStatement);
+
+  /**
+   * @returns the pointer to the owning BindingParamsArray.  Used by a
+   *          BindingParamsArray to verify that we belong to it when added.
+   */
+  const mozIStorageBindingParamsArray* getOwner() const;
+
+  BindingParams(mozIStorageBindingParamsArray* aOwningArray,
+                Statement* aOwningStatement);
+
+ protected:
+  virtual ~BindingParams() {}
+
+  explicit BindingParams(mozIStorageBindingParamsArray* aOwningArray);
+  // Note that this is managed as a sparse array, so particular caution should
+  // be used for out-of-bounds usage.
+  nsTArray<RefPtr<Variant_base> > mParameters;
+  bool mLocked;
+
+ private:
+  /**
+   * Track the BindingParamsArray that created us until we are added to it.
+   * (Once we are added we are locked and no one needs to look up our owner.)
+   * Ref-counted since there is no invariant that guarantees it stays alive
+   * otherwise.  This keeps mOwningStatement alive for us too since the array
+   * also holds a reference.
+   */
+  nsCOMPtr<mozIStorageBindingParamsArray> mOwningArray;
+  /**
+   * Used in the synchronous binding case to map parameter names to indices.
+   * Not reference-counted because this is only non-null as long as mOwningArray
+   * is non-null and mOwningArray also holds a statement reference.
+   */
+  Statement* mOwningStatement;
+  uint32_t mParamCount;
+};
+
+/**
+ * Adds late resolution of named parameters so they don't get resolved until we
+ * try and bind the parameters on the async thread.  We also stop checking
+ * parameter indices for being too big since we just just don't know how many
+ * there are.
+ *
+ * We support *either* binding by name or binding by index.  Trying to do both
+ * results in only binding by name at sqlite3_stmt bind time.
+ */
+class AsyncBindingParams : public BindingParams {
+ public:
+  NS_IMETHOD BindByName(const nsACString& aName, nsIVariant* aValue) override;
+  NS_IMETHOD BindByIndex(uint32_t aIndex, nsIVariant* aValue) override;
+
+  virtual already_AddRefed<mozIStorageError> bind(
+      sqlite3_stmt* aStatement) override;
+
+  explicit AsyncBindingParams(mozIStorageBindingParamsArray* aOwningArray);
+  virtual ~AsyncBindingParams() {}
+
+ private:
+  nsInterfaceHashtable<nsCStringHashKey, nsIVariant> mNamedParameters;
+};
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif  // mozStorageBindingParams_h
diff --git a/storage/mozStorageBindingParamsArray.cpp b/storage/mozStorageBindingParamsArray.cpp
new file mode 100644
index 0000000000..1913d44733
--- /dev/null
+++ b/storage/mozStorageBindingParamsArray.cpp
@@ -0,0 +1,75 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozStorageBindingParamsArray.h"
+#include "mozStorageBindingParams.h"
+#include "StorageBaseStatementInternal.h"
+
+namespace mozilla {
+namespace storage {
+
+////////////////////////////////////////////////////////////////////////////////
+//// BindingParamsArray
+
+BindingParamsArray::BindingParamsArray(
+    StorageBaseStatementInternal* aOwningStatement)
+    : mOwningStatement(aOwningStatement), mLocked(false) {}
+
+void BindingParamsArray::lock() {
+  NS_ASSERTION(mLocked == false, "Array has already been locked!");
+  mLocked = true;
+
+  // We also no longer need to hold a reference to our statement since it owns
+  // us.
+  mOwningStatement = nullptr;
+}
+
+const StorageBaseStatementInternal* BindingParamsArray::getOwner() const {
+  return mOwningStatement;
+}
+
+NS_IMPL_ISUPPORTS(BindingParamsArray, mozIStorageBindingParamsArray)
+
+///////////////////////////////////////////////////////////////////////////////
+//// mozIStorageBindingParamsArray
+
+NS_IMETHODIMP
+BindingParamsArray::NewBindingParams(mozIStorageBindingParams** _params) {
+  NS_ENSURE_FALSE(mLocked, NS_ERROR_UNEXPECTED);
+
+  nsCOMPtr<mozIStorageBindingParams> params(
+      mOwningStatement->newBindingParams(this));
+  NS_ENSURE_TRUE(params, NS_ERROR_UNEXPECTED);
+
+  params.forget(_params);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+BindingParamsArray::AddParams(mozIStorageBindingParams* aParameters) {
+  NS_ENSURE_FALSE(mLocked, NS_ERROR_UNEXPECTED);
+
+  BindingParams* params = static_cast<BindingParams*>(aParameters);
+
+  // Check to make sure that this set of parameters was created with us.
+  if (params->getOwner() != this) return NS_ERROR_UNEXPECTED;
+
+  mArray.AppendElement(params);
+
+  // Lock the parameters only after we've successfully added them.
+  params->lock();
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+BindingParamsArray::GetLength(uint32_t* _length) {
+  *_length = length();
+  return NS_OK;
+}
+
+}  // namespace storage
+}  // namespace mozilla
diff --git a/storage/mozStorageBindingParamsArray.h b/storage/mozStorageBindingParamsArray.h
new file mode 100644
index 0000000000..58d5a52ab6
--- /dev/null
+++ b/storage/mozStorageBindingParamsArray.h
@@ -0,0 +1,105 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozStorageBindingParamsArray_h
+#define mozStorageBindingParamsArray_h
+
+#include "nsCOMPtr.h"
+#include "nsTArray.h"
+#include "mozilla/Attributes.h"
+
+#include "mozIStorageBindingParamsArray.h"
+
+namespace mozilla {
+namespace storage {
+
+class StorageBaseStatementInternal;
+
+class BindingParamsArray final : public mozIStorageBindingParamsArray {
+  typedef nsTArray<nsCOMPtr<mozIStorageBindingParams> > array_type;
+
+  ~BindingParamsArray() {}
+
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEBINDINGPARAMSARRAY
+
+  explicit BindingParamsArray(StorageBaseStatementInternal* aOwningStatement);
+
+  typedef array_type::size_type size_type;
+
+  /**
+   * Locks the array and prevents further modification to it (such as adding
+   * more elements to it).
+   */
+  void lock();
+
+  /**
+   * @return the pointer to the owning BindingParamsArray.
+   */
+  const StorageBaseStatementInternal* getOwner() const;
+
+  /**
+   * @return the number of elemets the array contains.
+   */
+  size_type length() const { return mArray.Length(); }
+
+  class iterator {
+   public:
+    iterator(BindingParamsArray* aArray, uint32_t aIndex)
+        : mArray(aArray), mIndex(aIndex) {}
+
+    iterator& operator++(int) {
+      mIndex++;
+      return *this;
+    }
+
+    bool operator==(const iterator& aOther) const {
+      return mIndex == aOther.mIndex;
+    }
+    bool operator!=(const iterator& aOther) const { return !(*this == aOther); }
+    mozIStorageBindingParams* operator*() {
+      NS_ASSERTION(mIndex < mArray->length(),
+                   "Dereferenceing an invalid value!");
+      return mArray->mArray[mIndex].get();
+    }
+
+   private:
+    void operator--() {}
+    BindingParamsArray* mArray;
+    uint32_t mIndex;
+  };
+
+  /**
+   * Obtains an iterator pointing to the beginning of the array.
+   */
+  inline iterator begin() {
+    NS_ASSERTION(length() != 0,
+                 "Obtaining an iterator to the beginning with no elements!");
+    return iterator(this, 0);
+  }
+
+  /**
+   * Obtains an iterator pointing to the end of the array.
+   */
+  inline iterator end() {
+    NS_ASSERTION(mLocked,
+                 "Obtaining an iterator to the end when we are not locked!");
+    return iterator(this, length());
+  }
+
+ private:
+  nsCOMPtr<StorageBaseStatementInternal> mOwningStatement;
+  array_type mArray;
+  bool mLocked;
+
+  friend class iterator;
+};
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif  // mozStorageBindingParamsArray_h
diff --git a/storage/mozStorageConnection.cpp b/storage/mozStorageConnection.cpp
new file mode 100644
index 0000000000..e10458a68b
--- /dev/null
+++ b/storage/mozStorageConnection.cpp
@@ -0,0 +1,2981 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "BaseVFS.h"
+#include "ErrorList.h"
+#include "nsError.h"
+#include "nsThreadUtils.h"
+#include "nsIFile.h"
+#include "nsIFileURL.h"
+#include "nsIXPConnect.h"
+#include "mozilla/AppShutdown.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/CondVar.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/ErrorNames.h"
+#include "mozilla/Unused.h"
+#include "mozilla/dom/quota/QuotaObject.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/SpinEventLoopUntil.h"
+#include "mozilla/StaticPrefs_storage.h"
+
+#include "mozIStorageCompletionCallback.h"
+#include "mozIStorageFunction.h"
+
+#include "mozStorageAsyncStatementExecution.h"
+#include "mozStorageSQLFunctions.h"
+#include "mozStorageConnection.h"
+#include "mozStorageService.h"
+#include "mozStorageStatement.h"
+#include "mozStorageAsyncStatement.h"
+#include "mozStorageArgValueArray.h"
+#include "mozStoragePrivateHelpers.h"
+#include "mozStorageStatementData.h"
+#include "ObfuscatingVFS.h"
+#include "QuotaVFS.h"
+#include "StorageBaseStatementInternal.h"
+#include "SQLCollations.h"
+#include "FileSystemModule.h"
+#include "mozStorageHelper.h"
+
+#include "mozilla/Assertions.h"
+#include "mozilla/Logging.h"
+#include "mozilla/Printf.h"
+#include "mozilla/ProfilerLabels.h"
+#include "mozilla/RefPtr.h"
+#include "nsComponentManagerUtils.h"
+#include "nsProxyRelease.h"
+#include "nsStringFwd.h"
+#include "nsURLHelper.h"
+
+#define MIN_AVAILABLE_BYTES_PER_CHUNKED_GROWTH 524288000  // 500 MiB
+
+// Maximum size of the pages cache per connection.
+#define MAX_CACHE_SIZE_KIBIBYTES 2048  // 2 MiB
+
+mozilla::LazyLogModule gStorageLog("mozStorage");
+
+// Checks that the protected code is running on the main-thread only if the
+// connection was also opened on it.
+#ifdef DEBUG
+#  define CHECK_MAINTHREAD_ABUSE()                                   \
+    do {                                                             \
+      NS_WARNING_ASSERTION(                                          \
+          eventTargetOpenedOn == GetMainThreadSerialEventTarget() || \
+              !NS_IsMainThread(),                                    \
+          "Using Storage synchronous API on main-thread, but "       \
+          "the connection was opened on another thread.");           \
+    } while (0)
+#else
+#  define CHECK_MAINTHREAD_ABUSE() \
+    do { /* Nothing */             \
+    } while (0)
+#endif
+
+namespace mozilla::storage {
+
+using mozilla::dom::quota::QuotaObject;
+using mozilla::Telemetry::AccumulateCategoricalKeyed;
+using mozilla::Telemetry::LABELS_SQLITE_STORE_OPEN;
+using mozilla::Telemetry::LABELS_SQLITE_STORE_QUERY;
+
+namespace {
+
+int nsresultToSQLiteResult(nsresult aXPCOMResultCode) {
+  if (NS_SUCCEEDED(aXPCOMResultCode)) {
+    return SQLITE_OK;
+  }
+
+  switch (aXPCOMResultCode) {
+    case NS_ERROR_FILE_CORRUPTED:
+      return SQLITE_CORRUPT;
+    case NS_ERROR_FILE_ACCESS_DENIED:
+      return SQLITE_CANTOPEN;
+    case NS_ERROR_STORAGE_BUSY:
+      return SQLITE_BUSY;
+    case NS_ERROR_FILE_IS_LOCKED:
+      return SQLITE_LOCKED;
+    case NS_ERROR_FILE_READ_ONLY:
+      return SQLITE_READONLY;
+    case NS_ERROR_STORAGE_IOERR:
+      return SQLITE_IOERR;
+    case NS_ERROR_FILE_NO_DEVICE_SPACE:
+      return SQLITE_FULL;
+    case NS_ERROR_OUT_OF_MEMORY:
+      return SQLITE_NOMEM;
+    case NS_ERROR_UNEXPECTED:
+      return SQLITE_MISUSE;
+    case NS_ERROR_ABORT:
+      return SQLITE_ABORT;
+    case NS_ERROR_STORAGE_CONSTRAINT:
+      return SQLITE_CONSTRAINT;
+    default:
+      return SQLITE_ERROR;
+  }
+
+  MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE("Must return in switch above!");
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Variant Specialization Functions (variantToSQLiteT)
+
+int sqlite3_T_int(sqlite3_context* aCtx, int aValue) {
+  ::sqlite3_result_int(aCtx, aValue);
+  return SQLITE_OK;
+}
+
+int sqlite3_T_int64(sqlite3_context* aCtx, sqlite3_int64 aValue) {
+  ::sqlite3_result_int64(aCtx, aValue);
+  return SQLITE_OK;
+}
+
+int sqlite3_T_double(sqlite3_context* aCtx, double aValue) {
+  ::sqlite3_result_double(aCtx, aValue);
+  return SQLITE_OK;
+}
+
+int sqlite3_T_text(sqlite3_context* aCtx, const nsCString& aValue) {
+  CheckedInt<int32_t> length(aValue.Length());
+  if (!length.isValid()) {
+    return SQLITE_MISUSE;
+  }
+  ::sqlite3_result_text(aCtx, aValue.get(), length.value(), SQLITE_TRANSIENT);
+  return SQLITE_OK;
+}
+
+int sqlite3_T_text16(sqlite3_context* aCtx, const nsString& aValue) {
+  CheckedInt<int32_t> n_bytes =
+      CheckedInt<int32_t>(aValue.Length()) * sizeof(char16_t);
+  if (!n_bytes.isValid()) {
+    return SQLITE_MISUSE;
+  }
+  ::sqlite3_result_text16(aCtx, aValue.get(), n_bytes.value(),
+                          SQLITE_TRANSIENT);
+  return SQLITE_OK;
+}
+
+int sqlite3_T_null(sqlite3_context* aCtx) {
+  ::sqlite3_result_null(aCtx);
+  return SQLITE_OK;
+}
+
+int sqlite3_T_blob(sqlite3_context* aCtx, const void* aData, int aSize) {
+  ::sqlite3_result_blob(aCtx, aData, aSize, free);
+  return SQLITE_OK;
+}
+
+#include "variantToSQLiteT_impl.h"
+
+////////////////////////////////////////////////////////////////////////////////
+//// Modules
+
+struct Module {
+  const char* name;
+  int (*registerFunc)(sqlite3*, const char*);
+};
+
+Module gModules[] = {{"filesystem", RegisterFileSystemModule}};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Local Functions
+
+int tracefunc(unsigned aReason, void* aClosure, void* aP, void* aX) {
+  switch (aReason) {
+    case SQLITE_TRACE_STMT: {
+      // aP is a pointer to the prepared statement.
+      sqlite3_stmt* stmt = static_cast<sqlite3_stmt*>(aP);
+      // aX is a pointer to a string containing the unexpanded SQL or a comment,
+      // starting with "--"" in case of a trigger.
+      char* expanded = static_cast<char*>(aX);
+      // Simulate what sqlite_trace was doing.
+      if (!::strncmp(expanded, "--", 2)) {
+        MOZ_LOG(gStorageLog, LogLevel::Debug,
+                ("TRACE_STMT on %p: '%s'", aClosure, expanded));
+      } else {
+        char* sql = ::sqlite3_expanded_sql(stmt);
+        MOZ_LOG(gStorageLog, LogLevel::Debug,
+                ("TRACE_STMT on %p: '%s'", aClosure, sql));
+        ::sqlite3_free(sql);
+      }
+      break;
+    }
+    case SQLITE_TRACE_PROFILE: {
+      // aX is pointer to a 64bit integer containing nanoseconds it took to
+      // execute the last command.
+      sqlite_int64 time = *(static_cast<sqlite_int64*>(aX)) / 1000000;
+      if (time > 0) {
+        MOZ_LOG(gStorageLog, LogLevel::Debug,
+                ("TRACE_TIME on %p: %lldms", aClosure, time));
+      }
+      break;
+    }
+  }
+  return 0;
+}
+
+void basicFunctionHelper(sqlite3_context* aCtx, int aArgc,
+                         sqlite3_value** aArgv) {
+  void* userData = ::sqlite3_user_data(aCtx);
+
+  mozIStorageFunction* func = static_cast<mozIStorageFunction*>(userData);
+
+  RefPtr<ArgValueArray> arguments(new ArgValueArray(aArgc, aArgv));
+  if (!arguments) return;
+
+  nsCOMPtr<nsIVariant> result;
+  nsresult rv = func->OnFunctionCall(arguments, getter_AddRefs(result));
+  if (NS_FAILED(rv)) {
+    nsAutoCString errorMessage;
+    GetErrorName(rv, errorMessage);
+    errorMessage.InsertLiteral("User function returned ", 0);
+    errorMessage.Append('!');
+
+    NS_WARNING(errorMessage.get());
+
+    ::sqlite3_result_error(aCtx, errorMessage.get(), -1);
+    ::sqlite3_result_error_code(aCtx, nsresultToSQLiteResult(rv));
+    return;
+  }
+  int retcode = variantToSQLiteT(aCtx, result);
+  if (retcode != SQLITE_OK) {
+    NS_WARNING("User function returned invalid data type!");
+    ::sqlite3_result_error(aCtx, "User function returned invalid data type",
+                           -1);
+  }
+}
+
+RefPtr<QuotaObject> GetQuotaObject(sqlite3_file* aFile, bool obfuscatingVFS) {
+  return obfuscatingVFS
+             ? mozilla::storage::obfsvfs::GetQuotaObjectForFile(aFile)
+             : mozilla::storage::quotavfs::GetQuotaObjectForFile(aFile);
+}
+
+/**
+ * This code is heavily based on the sample at:
+ *   http://www.sqlite.org/unlock_notify.html
+ */
+class UnlockNotification {
+ public:
+  UnlockNotification()
+      : mMutex("UnlockNotification mMutex"),
+        mCondVar(mMutex, "UnlockNotification condVar"),
+        mSignaled(false) {}
+
+  void Wait() {
+    MutexAutoLock lock(mMutex);
+    while (!mSignaled) {
+      (void)mCondVar.Wait();
+    }
+  }
+
+  void Signal() {
+    MutexAutoLock lock(mMutex);
+    mSignaled = true;
+    (void)mCondVar.Notify();
+  }
+
+ private:
+  Mutex mMutex MOZ_UNANNOTATED;
+  CondVar mCondVar;
+  bool mSignaled;
+};
+
+void UnlockNotifyCallback(void** aArgs, int aArgsSize) {
+  for (int i = 0; i < aArgsSize; i++) {
+    UnlockNotification* notification =
+        static_cast<UnlockNotification*>(aArgs[i]);
+    notification->Signal();
+  }
+}
+
+int WaitForUnlockNotify(sqlite3* aDatabase) {
+  UnlockNotification notification;
+  int srv =
+      ::sqlite3_unlock_notify(aDatabase, UnlockNotifyCallback, &notification);
+  MOZ_ASSERT(srv == SQLITE_LOCKED || srv == SQLITE_OK);
+  if (srv == SQLITE_OK) {
+    notification.Wait();
+  }
+
+  return srv;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Local Classes
+
+class AsyncCloseConnection final : public Runnable {
+ public:
+  AsyncCloseConnection(Connection* aConnection, sqlite3* aNativeConnection,
+                       nsIRunnable* aCallbackEvent)
+      : Runnable("storage::AsyncCloseConnection"),
+        mConnection(aConnection),
+        mNativeConnection(aNativeConnection),
+        mCallbackEvent(aCallbackEvent) {}
+
+  NS_IMETHOD Run() override {
+    // Make sure we don't dispatch to the current thread.
+    MOZ_ASSERT(!IsOnCurrentSerialEventTarget(mConnection->eventTargetOpenedOn));
+
+    nsCOMPtr<nsIRunnable> event =
+        NewRunnableMethod("storage::Connection::shutdownAsyncThread",
+                          mConnection, &Connection::shutdownAsyncThread);
+    MOZ_ALWAYS_SUCCEEDS(NS_DispatchToMainThread(event));
+
+    // Internal close.
+    (void)mConnection->internalClose(mNativeConnection);
+
+    // Callback
+    if (mCallbackEvent) {
+      nsCOMPtr<nsIThread> thread;
+      (void)NS_GetMainThread(getter_AddRefs(thread));
+      (void)thread->Dispatch(mCallbackEvent, NS_DISPATCH_NORMAL);
+    }
+
+    return NS_OK;
+  }
+
+  ~AsyncCloseConnection() override {
+    NS_ReleaseOnMainThread("AsyncCloseConnection::mConnection",
+                           mConnection.forget());
+    NS_ReleaseOnMainThread("AsyncCloseConnection::mCallbackEvent",
+                           mCallbackEvent.forget());
+  }
+
+ private:
+  RefPtr<Connection> mConnection;
+  sqlite3* mNativeConnection;
+  nsCOMPtr<nsIRunnable> mCallbackEvent;
+};
+
+/**
+ * An event used to initialize the clone of a connection.
+ *
+ * Must be executed on the clone's async execution thread.
+ */
+class AsyncInitializeClone final : public Runnable {
+ public:
+  /**
+   * @param aConnection The connection being cloned.
+   * @param aClone The clone.
+   * @param aReadOnly If |true|, the clone is read only.
+   * @param aCallback A callback to trigger once initialization
+   *                  is complete. This event will be called on
+   *                  aClone->eventTargetOpenedOn.
+   */
+  AsyncInitializeClone(Connection* aConnection, Connection* aClone,
+                       const bool aReadOnly,
+                       mozIStorageCompletionCallback* aCallback)
+      : Runnable("storage::AsyncInitializeClone"),
+        mConnection(aConnection),
+        mClone(aClone),
+        mReadOnly(aReadOnly),
+        mCallback(aCallback) {
+    MOZ_ASSERT(NS_IsMainThread());
+  }
+
+  NS_IMETHOD Run() override {
+    MOZ_ASSERT(!NS_IsMainThread());
+    nsresult rv = mConnection->initializeClone(mClone, mReadOnly);
+    if (NS_FAILED(rv)) {
+      return Dispatch(rv, nullptr);
+    }
+    return Dispatch(NS_OK,
+                    NS_ISUPPORTS_CAST(mozIStorageAsyncConnection*, mClone));
+  }
+
+ private:
+  nsresult Dispatch(nsresult aResult, nsISupports* aValue) {
+    RefPtr<CallbackComplete> event =
+        new CallbackComplete(aResult, aValue, mCallback.forget());
+    return mClone->eventTargetOpenedOn->Dispatch(event, NS_DISPATCH_NORMAL);
+  }
+
+  ~AsyncInitializeClone() override {
+    nsCOMPtr<nsIThread> thread;
+    DebugOnly<nsresult> rv = NS_GetMainThread(getter_AddRefs(thread));
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+
+    // Handle ambiguous nsISupports inheritance.
+    NS_ProxyRelease("AsyncInitializeClone::mConnection", thread,
+                    mConnection.forget());
+    NS_ProxyRelease("AsyncInitializeClone::mClone", thread, mClone.forget());
+
+    // Generally, the callback will be released by CallbackComplete.
+    // However, if for some reason Run() is not executed, we still
+    // need to ensure that it is released here.
+    NS_ProxyRelease("AsyncInitializeClone::mCallback", thread,
+                    mCallback.forget());
+  }
+
+  RefPtr<Connection> mConnection;
+  RefPtr<Connection> mClone;
+  const bool mReadOnly;
+  nsCOMPtr<mozIStorageCompletionCallback> mCallback;
+};
+
+/**
+ * A listener for async connection closing.
+ */
+class CloseListener final : public mozIStorageCompletionCallback {
+ public:
+  NS_DECL_ISUPPORTS
+  CloseListener() : mClosed(false) {}
+
+  NS_IMETHOD Complete(nsresult, nsISupports*) override {
+    mClosed = true;
+    return NS_OK;
+  }
+
+  bool mClosed;
+
+ private:
+  ~CloseListener() = default;
+};
+
+NS_IMPL_ISUPPORTS(CloseListener, mozIStorageCompletionCallback)
+
+class AsyncVacuumEvent final : public Runnable {
+ public:
+  AsyncVacuumEvent(Connection* aConnection,
+                   mozIStorageCompletionCallback* aCallback,
+                   bool aUseIncremental, int32_t aSetPageSize)
+      : Runnable("storage::AsyncVacuum"),
+        mConnection(aConnection),
+        mCallback(aCallback),
+        mUseIncremental(aUseIncremental),
+        mSetPageSize(aSetPageSize),
+        mStatus(NS_ERROR_UNEXPECTED) {}
+
+  NS_IMETHOD Run() override {
+    // This is initially dispatched to the helper thread, then re-dispatched
+    // to the opener thread, where it will callback.
+    if (IsOnCurrentSerialEventTarget(mConnection->eventTargetOpenedOn)) {
+      // Send the completion event.
+      if (mCallback) {
+        mozilla::Unused << mCallback->Complete(mStatus, nullptr);
+      }
+      return NS_OK;
+    }
+
+    // Ensure to invoke the callback regardless of errors.
+    auto guard = MakeScopeExit([&]() {
+      mConnection->mIsStatementOnHelperThreadInterruptible = false;
+      mozilla::Unused << mConnection->eventTargetOpenedOn->Dispatch(
+          this, NS_DISPATCH_NORMAL);
+    });
+
+    // Get list of attached databases.
+    nsCOMPtr<mozIStorageStatement> stmt;
+    nsresult rv = mConnection->CreateStatement(MOZ_STORAGE_UNIQUIFY_QUERY_STR
+                                               "PRAGMA database_list"_ns,
+                                               getter_AddRefs(stmt));
+    NS_ENSURE_SUCCESS(rv, rv);
+    // We must accumulate names and loop through them later, otherwise VACUUM
+    // will see an ongoing statement and bail out.
+    nsTArray<nsCString> schemaNames;
+    bool hasResult = false;
+    while (stmt && NS_SUCCEEDED(stmt->ExecuteStep(&hasResult)) && hasResult) {
+      nsAutoCString name;
+      rv = stmt->GetUTF8String(1, name);
+      if (NS_SUCCEEDED(rv) && !name.EqualsLiteral("temp")) {
+        schemaNames.AppendElement(name);
+      }
+    }
+    mStatus = NS_OK;
+    // Mark this vacuum as an interruptible operation, so it can be interrupted
+    // if the connection closes during shutdown.
+    mConnection->mIsStatementOnHelperThreadInterruptible = true;
+    for (const nsCString& schemaName : schemaNames) {
+      rv = this->Vacuum(schemaName);
+      if (NS_FAILED(rv)) {
+        // This is sub-optimal since it's only keeping the last error reason,
+        // but it will do for now.
+        mStatus = rv;
+      }
+    }
+    return mStatus;
+  }
+
+  nsresult Vacuum(const nsACString& aSchemaName) {
+    // Abort if we're in shutdown.
+    if (AppShutdown::IsInOrBeyond(ShutdownPhase::AppShutdownConfirmed)) {
+      return NS_ERROR_ABORT;
+    }
+    int32_t removablePages = mConnection->RemovablePagesInFreeList(aSchemaName);
+    if (!removablePages) {
+      // There's no empty pages to remove, so skip this vacuum for now.
+      return NS_OK;
+    }
+    nsresult rv;
+    bool needsFullVacuum = true;
+
+    if (mSetPageSize) {
+      nsAutoCString query(MOZ_STORAGE_UNIQUIFY_QUERY_STR "PRAGMA ");
+      query.Append(aSchemaName);
+      query.AppendLiteral(".page_size = ");
+      query.AppendInt(mSetPageSize);
+      nsCOMPtr<mozIStorageStatement> stmt;
+      rv = mConnection->ExecuteSimpleSQL(query);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    // Check auto_vacuum.
+    {
+      nsAutoCString query(MOZ_STORAGE_UNIQUIFY_QUERY_STR "PRAGMA ");
+      query.Append(aSchemaName);
+      query.AppendLiteral(".auto_vacuum");
+      nsCOMPtr<mozIStorageStatement> stmt;
+      rv = mConnection->CreateStatement(query, getter_AddRefs(stmt));
+      NS_ENSURE_SUCCESS(rv, rv);
+      bool hasResult = false;
+      bool changeAutoVacuum = false;
+      if (stmt && NS_SUCCEEDED(stmt->ExecuteStep(&hasResult)) && hasResult) {
+        bool isIncrementalVacuum = stmt->AsInt32(0) == 2;
+        changeAutoVacuum = isIncrementalVacuum != mUseIncremental;
+        if (isIncrementalVacuum && !changeAutoVacuum) {
+          needsFullVacuum = false;
+        }
+      }
+      // Changing auto_vacuum is only supported on the main schema.
+      if (aSchemaName.EqualsLiteral("main") && changeAutoVacuum) {
+        nsAutoCString query(MOZ_STORAGE_UNIQUIFY_QUERY_STR "PRAGMA ");
+        query.Append(aSchemaName);
+        query.AppendLiteral(".auto_vacuum = ");
+        query.AppendInt(mUseIncremental ? 2 : 0);
+        rv = mConnection->ExecuteSimpleSQL(query);
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+    }
+
+    if (needsFullVacuum) {
+      nsAutoCString query(MOZ_STORAGE_UNIQUIFY_QUERY_STR "VACUUM ");
+      query.Append(aSchemaName);
+      rv = mConnection->ExecuteSimpleSQL(query);
+      // TODO (Bug 1818039): Report failed vacuum telemetry.
+      NS_ENSURE_SUCCESS(rv, rv);
+    } else {
+      nsAutoCString query(MOZ_STORAGE_UNIQUIFY_QUERY_STR "PRAGMA ");
+      query.Append(aSchemaName);
+      query.AppendLiteral(".incremental_vacuum(");
+      query.AppendInt(removablePages);
+      query.AppendLiteral(")");
+      rv = mConnection->ExecuteSimpleSQL(query);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    return NS_OK;
+  }
+
+  ~AsyncVacuumEvent() override {
+    NS_ReleaseOnMainThread("AsyncVacuum::mConnection", mConnection.forget());
+    NS_ReleaseOnMainThread("AsyncVacuum::mCallback", mCallback.forget());
+  }
+
+ private:
+  RefPtr<Connection> mConnection;
+  nsCOMPtr<mozIStorageCompletionCallback> mCallback;
+  bool mUseIncremental;
+  int32_t mSetPageSize;
+  Atomic<nsresult> mStatus;
+};
+
+/**
+ * A runnable to perform an SQLite database backup when there may be one or more
+ * open connections on that database.
+ */
+class AsyncBackupDatabaseFile final : public Runnable, public nsITimerCallback {
+ public:
+  NS_DECL_ISUPPORTS_INHERITED
+
+  /**
+   * @param aConnection The connection to the database being backed up.
+   * @param aNativeConnection The native connection to the database being backed
+   *                          up.
+   * @param aDestinationFile The destination file for the created backup.
+   * @param aCallback A callback to trigger once the backup process has
+   *                  completed. The callback will be supplied with an nsresult
+   *                  indicating whether or not the backup was successfully
+   *                  created. This callback will be called on the
+   *                  mConnection->eventTargetOpenedOn thread.
+   * @throws
+   */
+  AsyncBackupDatabaseFile(Connection* aConnection, sqlite3* aNativeConnection,
+                          nsIFile* aDestinationFile,
+                          mozIStorageCompletionCallback* aCallback)
+      : Runnable("storage::AsyncBackupDatabaseFile"),
+        mConnection(aConnection),
+        mNativeConnection(aNativeConnection),
+        mDestinationFile(aDestinationFile),
+        mCallback(aCallback),
+        mBackupFile(nullptr),
+        mBackupHandle(nullptr) {
+    MOZ_ASSERT(NS_IsMainThread());
+  }
+
+  NS_IMETHOD Run() override {
+    MOZ_ASSERT(!NS_IsMainThread());
+
+    nsAutoString path;
+    nsresult rv = mDestinationFile->GetPath(path);
+    if (NS_FAILED(rv)) {
+      return Dispatch(rv, nullptr);
+    }
+    // Put a .tmp on the end of the destination while the backup is underway.
+    // This extension will be stripped off after the backup successfully
+    // completes.
+    path.AppendLiteral(".tmp");
+
+    int srv = ::sqlite3_open(NS_ConvertUTF16toUTF8(path).get(), &mBackupFile);
+    if (srv != SQLITE_OK) {
+      return Dispatch(NS_ERROR_FAILURE, nullptr);
+    }
+
+    static const char* mainDBName = "main";
+
+    mBackupHandle = ::sqlite3_backup_init(mBackupFile, mainDBName,
+                                          mNativeConnection, mainDBName);
+    if (!mBackupHandle) {
+      MOZ_ALWAYS_TRUE(::sqlite3_close(mBackupFile) == SQLITE_OK);
+      return Dispatch(NS_ERROR_FAILURE, nullptr);
+    }
+
+    return DoStep();
+  }
+
+  NS_IMETHOD
+  Notify(nsITimer* aTimer) override { return DoStep(); }
+
+ private:
+  nsresult DoStep() {
+#define DISPATCH_AND_RETURN_IF_FAILED(rv) \
+  if (NS_FAILED(rv)) {                    \
+    return Dispatch(rv, nullptr);         \
+  }
+
+    // This guard is used to close the backup database in the event of
+    // some failure throughout this process. We release the exit guard
+    // only if we complete the backup successfully, or defer to another
+    // later call to DoStep.
+    auto guard = MakeScopeExit([&]() {
+      MOZ_ALWAYS_TRUE(::sqlite3_close(mBackupFile) == SQLITE_OK);
+      mBackupFile = nullptr;
+    });
+
+    MOZ_ASSERT(!NS_IsMainThread());
+    nsAutoString originalPath;
+    nsresult rv = mDestinationFile->GetPath(originalPath);
+    DISPATCH_AND_RETURN_IF_FAILED(rv);
+
+    nsAutoString tempPath = originalPath;
+    tempPath.AppendLiteral(".tmp");
+
+    nsCOMPtr<nsIFile> file =
+        do_CreateInstance("@mozilla.org/file/local;1", &rv);
+    DISPATCH_AND_RETURN_IF_FAILED(rv);
+
+    rv = file->InitWithPath(tempPath);
+    DISPATCH_AND_RETURN_IF_FAILED(rv);
+
+    // The number of milliseconds to wait between each batch of copies.
+    static constexpr uint32_t STEP_DELAY_MS = 250;
+    // The number of pages to copy per step
+    static constexpr int COPY_PAGES = 5;
+
+    int srv = ::sqlite3_backup_step(mBackupHandle, COPY_PAGES);
+    if (srv == SQLITE_OK || srv == SQLITE_BUSY || srv == SQLITE_LOCKED) {
+      // We're continuing the backup later. Release the guard to avoid closing
+      // the database.
+      guard.release();
+      // Queue up the next step
+      return NS_NewTimerWithCallback(getter_AddRefs(mTimer), this,
+                                     STEP_DELAY_MS, nsITimer::TYPE_ONE_SHOT,
+                                     GetCurrentSerialEventTarget());
+    }
+#ifdef DEBUG
+    if (srv != SQLITE_DONE) {
+      nsCString warnMsg;
+      warnMsg.AppendLiteral(
+          "The SQLite database copy could not be completed due to an error: ");
+      warnMsg.Append(::sqlite3_errmsg(mBackupFile));
+      NS_WARNING(warnMsg.get());
+    }
+#endif
+
+    (void)::sqlite3_backup_finish(mBackupHandle);
+    MOZ_ALWAYS_TRUE(::sqlite3_close(mBackupFile) == SQLITE_OK);
+    mBackupFile = nullptr;
+
+    // The database is already closed, so we can release this guard now.
+    guard.release();
+
+    if (srv != SQLITE_DONE) {
+      NS_WARNING("Failed to create database copy.");
+
+      // The partially created database file is not useful. Let's remove it.
+      rv = file->Remove(false);
+      if (NS_FAILED(rv)) {
+        NS_WARNING(
+            "Removing a partially backed up SQLite database file failed.");
+      }
+
+      return Dispatch(convertResultCode(srv), nullptr);
+    }
+
+    // Now that we've successfully created the copy, we'll strip off the .tmp
+    // extension.
+
+    nsAutoString leafName;
+    rv = mDestinationFile->GetLeafName(leafName);
+    DISPATCH_AND_RETURN_IF_FAILED(rv);
+
+    rv = file->RenameTo(nullptr, leafName);
+    DISPATCH_AND_RETURN_IF_FAILED(rv);
+
+#undef DISPATCH_AND_RETURN_IF_FAILED
+    return Dispatch(NS_OK, nullptr);
+  }
+
+  nsresult Dispatch(nsresult aResult, nsISupports* aValue) {
+    RefPtr<CallbackComplete> event =
+        new CallbackComplete(aResult, aValue, mCallback.forget());
+    return mConnection->eventTargetOpenedOn->Dispatch(event,
+                                                      NS_DISPATCH_NORMAL);
+  }
+
+  ~AsyncBackupDatabaseFile() override {
+    nsresult rv;
+    nsCOMPtr<nsIThread> thread =
+        do_QueryInterface(mConnection->eventTargetOpenedOn, &rv);
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+
+    // Handle ambiguous nsISupports inheritance.
+    NS_ProxyRelease("AsyncBackupDatabaseFile::mConnection", thread,
+                    mConnection.forget());
+    NS_ProxyRelease("AsyncBackupDatabaseFile::mDestinationFile", thread,
+                    mDestinationFile.forget());
+
+    // Generally, the callback will be released by CallbackComplete.
+    // However, if for some reason Run() is not executed, we still
+    // need to ensure that it is released here.
+    NS_ProxyRelease("AsyncInitializeClone::mCallback", thread,
+                    mCallback.forget());
+  }
+
+  RefPtr<Connection> mConnection;
+  sqlite3* mNativeConnection;
+  nsCOMPtr<nsITimer> mTimer;
+  nsCOMPtr<nsIFile> mDestinationFile;
+  nsCOMPtr<mozIStorageCompletionCallback> mCallback;
+  sqlite3* mBackupFile;
+  sqlite3_backup* mBackupHandle;
+};
+
+NS_IMPL_ISUPPORTS_INHERITED(AsyncBackupDatabaseFile, Runnable, nsITimerCallback)
+
+}  // namespace
+
+////////////////////////////////////////////////////////////////////////////////
+//// Connection
+
+Connection::Connection(Service* aService, int aFlags,
+                       ConnectionOperation aSupportedOperations,
+                       const nsCString& aTelemetryFilename, bool aInterruptible,
+                       bool aIgnoreLockingMode)
+    : sharedAsyncExecutionMutex("Connection::sharedAsyncExecutionMutex"),
+      sharedDBMutex("Connection::sharedDBMutex"),
+      eventTargetOpenedOn(WrapNotNull(GetCurrentSerialEventTarget())),
+      mIsStatementOnHelperThreadInterruptible(false),
+      mDBConn(nullptr),
+      mDefaultTransactionType(mozIStorageConnection::TRANSACTION_DEFERRED),
+      mDestroying(false),
+      mProgressHandler(nullptr),
+      mStorageService(aService),
+      mFlags(aFlags),
+      mTransactionNestingLevel(0),
+      mSupportedOperations(aSupportedOperations),
+      mInterruptible(aSupportedOperations == Connection::ASYNCHRONOUS ||
+                     aInterruptible),
+      mIgnoreLockingMode(aIgnoreLockingMode),
+      mAsyncExecutionThreadShuttingDown(false),
+      mConnectionClosed(false),
+      mGrowthChunkSize(0) {
+  MOZ_ASSERT(!mIgnoreLockingMode || mFlags & SQLITE_OPEN_READONLY,
+             "Can't ignore locking for a non-readonly connection!");
+  mStorageService->registerConnection(this);
+  MOZ_ASSERT(!aTelemetryFilename.IsEmpty(),
+             "A telemetry filename should have been passed-in.");
+  mTelemetryFilename.Assign(aTelemetryFilename);
+}
+
+Connection::~Connection() {
+  // Failsafe Close() occurs in our custom Release method because of
+  // complications related to Close() potentially invoking AsyncClose() which
+  // will increment our refcount.
+  MOZ_ASSERT(!mAsyncExecutionThread,
+             "The async thread has not been shutdown properly!");
+}
+
+NS_IMPL_ADDREF(Connection)
+
+NS_INTERFACE_MAP_BEGIN(Connection)
+  NS_INTERFACE_MAP_ENTRY(mozIStorageAsyncConnection)
+  NS_INTERFACE_MAP_ENTRY(nsIInterfaceRequestor)
+  NS_INTERFACE_MAP_ENTRY(mozIStorageConnection)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, mozIStorageConnection)
+NS_INTERFACE_MAP_END
+
+// This is identical to what NS_IMPL_RELEASE provides, but with the
+// extra |1 == count| case.
+NS_IMETHODIMP_(MozExternalRefCountType) Connection::Release(void) {
+  MOZ_ASSERT(0 != mRefCnt, "dup release");
+  nsrefcnt count = --mRefCnt;
+  NS_LOG_RELEASE(this, count, "Connection");
+  if (1 == count) {
+    // If the refcount went to 1, the single reference must be from
+    // gService->mConnections (in class |Service|).  And the code calling
+    // Release is either:
+    // - The "user" code that had created the connection, releasing on any
+    //   thread.
+    // - One of Service's getConnections() callers had acquired a strong
+    //   reference to the Connection that out-lived the last "user" reference,
+    //   and now that just got dropped.  Note that this reference could be
+    //   getting dropped on the main thread or Connection->eventTargetOpenedOn
+    //   (because of the NewRunnableMethod used by minimizeMemory).
+    //
+    // Either way, we should now perform our failsafe Close() and unregister.
+    // However, we only want to do this once, and the reality is that our
+    // refcount could go back up above 1 and down again at any time if we are
+    // off the main thread and getConnections() gets called on the main thread,
+    // so we use an atomic here to do this exactly once.
+    if (mDestroying.compareExchange(false, true)) {
+      // Close the connection, dispatching to the opening event target if we're
+      // not on that event target already and that event target is still
+      // accepting runnables. We do this because it's possible we're on the main
+      // thread because of getConnections(), and we REALLY don't want to
+      // transfer I/O to the main thread if we can avoid it.
+      if (IsOnCurrentSerialEventTarget(eventTargetOpenedOn)) {
+        // This could cause SpinningSynchronousClose() to be invoked and AddRef
+        // triggered for AsyncCloseConnection's strong ref if the conn was ever
+        // use for async purposes.  (Main-thread only, though.)
+        Unused << synchronousClose();
+      } else {
+        nsCOMPtr<nsIRunnable> event =
+            NewRunnableMethod("storage::Connection::synchronousClose", this,
+                              &Connection::synchronousClose);
+        if (NS_FAILED(eventTargetOpenedOn->Dispatch(event.forget(),
+                                                    NS_DISPATCH_NORMAL))) {
+          // The event target was dead and so we've just leaked our runnable.
+          // This should not happen because our non-main-thread consumers should
+          // be explicitly closing their connections, not relying on us to close
+          // them for them.  (It's okay to let a statement go out of scope for
+          // automatic cleanup, but not a Connection.)
+          MOZ_ASSERT(false,
+                     "Leaked Connection::synchronousClose(), ownership fail.");
+          Unused << synchronousClose();
+        }
+      }
+
+      // This will drop its strong reference right here, right now.
+      mStorageService->unregisterConnection(this);
+    }
+  } else if (0 == count) {
+    mRefCnt = 1; /* stabilize */
+#if 0            /* enable this to find non-threadsafe destructors: */
+    NS_ASSERT_OWNINGTHREAD(Connection);
+#endif
+    delete (this);
+    return 0;
+  }
+  return count;
+}
+
+int32_t Connection::getSqliteRuntimeStatus(int32_t aStatusOption,
+                                           int32_t* aMaxValue) {
+  MOZ_ASSERT(connectionReady(), "A connection must exist at this point");
+  int curr = 0, max = 0;
+  DebugOnly<int> rc =
+      ::sqlite3_db_status(mDBConn, aStatusOption, &curr, &max, 0);
+  MOZ_ASSERT(NS_SUCCEEDED(convertResultCode(rc)));
+  if (aMaxValue) *aMaxValue = max;
+  return curr;
+}
+
+nsIEventTarget* Connection::getAsyncExecutionTarget() {
+  NS_ENSURE_TRUE(IsOnCurrentSerialEventTarget(eventTargetOpenedOn), nullptr);
+
+  // Don't return the asynchronous event target if we are shutting down.
+  if (mAsyncExecutionThreadShuttingDown) {
+    return nullptr;
+  }
+
+  // Create the async event target if there's none yet.
+  if (!mAsyncExecutionThread) {
+    // Names start with "sqldb:" followed by a recognizable name, like the
+    // database file name, or a specially crafted name like "memory".
+    // This name will be surfaced on https://crash-stats.mozilla.org, so any
+    // sensitive part of the file name (e.g. an URL origin) should be replaced
+    // by passing an explicit telemetryName to openDatabaseWithFileURL.
+    nsAutoCString name("sqldb:"_ns);
+    name.Append(mTelemetryFilename);
+    static nsThreadPoolNaming naming;
+    nsresult rv = NS_NewNamedThread(naming.GetNextThreadName(name),
+                                    getter_AddRefs(mAsyncExecutionThread));
+    if (NS_FAILED(rv)) {
+      NS_WARNING("Failed to create async thread.");
+      return nullptr;
+    }
+    mAsyncExecutionThread->SetNameForWakeupTelemetry("mozStorage (all)"_ns);
+  }
+
+  return mAsyncExecutionThread;
+}
+
+void Connection::RecordOpenStatus(nsresult rv) {
+  nsCString histogramKey = mTelemetryFilename;
+
+  if (histogramKey.IsEmpty()) {
+    histogramKey.AssignLiteral("unknown");
+  }
+
+  if (NS_SUCCEEDED(rv)) {
+    AccumulateCategoricalKeyed(histogramKey, LABELS_SQLITE_STORE_OPEN::success);
+    return;
+  }
+
+  switch (rv) {
+    case NS_ERROR_FILE_CORRUPTED:
+      AccumulateCategoricalKeyed(histogramKey,
+                                 LABELS_SQLITE_STORE_OPEN::corrupt);
+      break;
+    case NS_ERROR_STORAGE_IOERR:
+      AccumulateCategoricalKeyed(histogramKey,
+                                 LABELS_SQLITE_STORE_OPEN::diskio);
+      break;
+    case NS_ERROR_FILE_ACCESS_DENIED:
+    case NS_ERROR_FILE_IS_LOCKED:
+    case NS_ERROR_FILE_READ_ONLY:
+      AccumulateCategoricalKeyed(histogramKey,
+                                 LABELS_SQLITE_STORE_OPEN::access);
+      break;
+    case NS_ERROR_FILE_NO_DEVICE_SPACE:
+      AccumulateCategoricalKeyed(histogramKey,
+                                 LABELS_SQLITE_STORE_OPEN::diskspace);
+      break;
+    default:
+      AccumulateCategoricalKeyed(histogramKey,
+                                 LABELS_SQLITE_STORE_OPEN::failure);
+  }
+}
+
+void Connection::RecordQueryStatus(int srv) {
+  nsCString histogramKey = mTelemetryFilename;
+
+  if (histogramKey.IsEmpty()) {
+    histogramKey.AssignLiteral("unknown");
+  }
+
+  switch (srv) {
+    case SQLITE_OK:
+    case SQLITE_ROW:
+    case SQLITE_DONE:
+
+    // Note that these are returned when we intentionally cancel a statement so
+    // they aren't indicating a failure.
+    case SQLITE_ABORT:
+    case SQLITE_INTERRUPT:
+      AccumulateCategoricalKeyed(histogramKey,
+                                 LABELS_SQLITE_STORE_QUERY::success);
+      break;
+    case SQLITE_CORRUPT:
+    case SQLITE_NOTADB:
+      AccumulateCategoricalKeyed(histogramKey,
+                                 LABELS_SQLITE_STORE_QUERY::corrupt);
+      break;
+    case SQLITE_PERM:
+    case SQLITE_CANTOPEN:
+    case SQLITE_LOCKED:
+    case SQLITE_READONLY:
+      AccumulateCategoricalKeyed(histogramKey,
+                                 LABELS_SQLITE_STORE_QUERY::access);
+      break;
+    case SQLITE_IOERR:
+    case SQLITE_NOLFS:
+      AccumulateCategoricalKeyed(histogramKey,
+                                 LABELS_SQLITE_STORE_QUERY::diskio);
+      break;
+    case SQLITE_FULL:
+    case SQLITE_TOOBIG:
+      AccumulateCategoricalKeyed(histogramKey,
+                                 LABELS_SQLITE_STORE_QUERY::diskspace);
+      break;
+    case SQLITE_CONSTRAINT:
+    case SQLITE_RANGE:
+    case SQLITE_MISMATCH:
+    case SQLITE_MISUSE:
+      AccumulateCategoricalKeyed(histogramKey,
+                                 LABELS_SQLITE_STORE_QUERY::misuse);
+      break;
+    case SQLITE_BUSY:
+      AccumulateCategoricalKeyed(histogramKey, LABELS_SQLITE_STORE_QUERY::busy);
+      break;
+    default:
+      AccumulateCategoricalKeyed(histogramKey,
+                                 LABELS_SQLITE_STORE_QUERY::failure);
+  }
+}
+
+nsresult Connection::initialize(const nsACString& aStorageKey,
+                                const nsACString& aName) {
+  MOZ_ASSERT(aStorageKey.Equals(kMozStorageMemoryStorageKey));
+  NS_ASSERTION(!connectionReady(),
+               "Initialize called on already opened database!");
+  MOZ_ASSERT(!mIgnoreLockingMode, "Can't ignore locking on an in-memory db.");
+  AUTO_PROFILER_LABEL("Connection::initialize", OTHER);
+
+  mStorageKey = aStorageKey;
+  mName = aName;
+
+  // in memory database requested, sqlite uses a magic file name
+
+  const nsAutoCString path =
+      mName.IsEmpty() ? nsAutoCString(":memory:"_ns)
+                      : "file:"_ns + mName + "?mode=memory&cache=shared"_ns;
+
+  int srv = ::sqlite3_open_v2(path.get(), &mDBConn, mFlags,
+                              basevfs::GetVFSName(true));
+  if (srv != SQLITE_OK) {
+    mDBConn = nullptr;
+    nsresult rv = convertResultCode(srv);
+    RecordOpenStatus(rv);
+    return rv;
+  }
+
+#ifdef MOZ_SQLITE_FTS3_TOKENIZER
+  srv =
+      ::sqlite3_db_config(mDBConn, SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, 1, 0);
+  MOZ_ASSERT(srv == SQLITE_OK,
+             "SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER should be enabled");
+#endif
+
+  // Do not set mDatabaseFile or mFileURL here since this is a "memory"
+  // database.
+
+  nsresult rv = initializeInternal();
+  RecordOpenStatus(rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult Connection::initialize(nsIFile* aDatabaseFile) {
+  NS_ASSERTION(aDatabaseFile, "Passed null file!");
+  NS_ASSERTION(!connectionReady(),
+               "Initialize called on already opened database!");
+  AUTO_PROFILER_LABEL("Connection::initialize", OTHER);
+
+  // Do not set mFileURL here since this is database does not have an associated
+  // URL.
+  mDatabaseFile = aDatabaseFile;
+
+  nsAutoString path;
+  nsresult rv = aDatabaseFile->GetPath(path);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool exclusive = StaticPrefs::storage_sqlite_exclusiveLock_enabled();
+  int srv;
+  if (mIgnoreLockingMode) {
+    exclusive = false;
+    srv = ::sqlite3_open_v2(NS_ConvertUTF16toUTF8(path).get(), &mDBConn, mFlags,
+                            "readonly-immutable-nolock");
+  } else {
+    srv = ::sqlite3_open_v2(NS_ConvertUTF16toUTF8(path).get(), &mDBConn, mFlags,
+                            basevfs::GetVFSName(exclusive));
+    if (exclusive && (srv == SQLITE_LOCKED || srv == SQLITE_BUSY)) {
+      // Retry without trying to get an exclusive lock.
+      exclusive = false;
+      srv = ::sqlite3_open_v2(NS_ConvertUTF16toUTF8(path).get(), &mDBConn,
+                              mFlags, basevfs::GetVFSName(false));
+    }
+  }
+  if (srv != SQLITE_OK) {
+    mDBConn = nullptr;
+    rv = convertResultCode(srv);
+    RecordOpenStatus(rv);
+    return rv;
+  }
+
+  rv = initializeInternal();
+  if (exclusive &&
+      (rv == NS_ERROR_STORAGE_BUSY || rv == NS_ERROR_FILE_IS_LOCKED)) {
+    // Usually SQLite will fail to acquire an exclusive lock on opening, but in
+    // some cases it may successfully open the database and then lock on the
+    // first query execution. When initializeInternal fails it closes the
+    // connection, so we can try to restart it in non-exclusive mode.
+    srv = ::sqlite3_open_v2(NS_ConvertUTF16toUTF8(path).get(), &mDBConn, mFlags,
+                            basevfs::GetVFSName(false));
+    if (srv == SQLITE_OK) {
+      rv = initializeInternal();
+    }
+  }
+
+  RecordOpenStatus(rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult Connection::initialize(nsIFileURL* aFileURL) {
+  NS_ASSERTION(aFileURL, "Passed null file URL!");
+  NS_ASSERTION(!connectionReady(),
+               "Initialize called on already opened database!");
+  AUTO_PROFILER_LABEL("Connection::initialize", OTHER);
+
+  nsCOMPtr<nsIFile> databaseFile;
+  nsresult rv = aFileURL->GetFile(getter_AddRefs(databaseFile));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Set both mDatabaseFile and mFileURL here.
+  mFileURL = aFileURL;
+  mDatabaseFile = databaseFile;
+
+  nsAutoCString spec;
+  rv = aFileURL->GetSpec(spec);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // If there is a key specified, we need to use the obfuscating VFS.
+  nsAutoCString query;
+  rv = aFileURL->GetQuery(query);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool hasKey = false;
+  bool hasDirectoryLockId = false;
+
+  MOZ_ALWAYS_TRUE(URLParams::Parse(
+      query, [&hasKey, &hasDirectoryLockId](const nsAString& aName,
+                                            const nsAString& aValue) {
+        if (aName.EqualsLiteral("key")) {
+          hasKey = true;
+          return true;
+        }
+        if (aName.EqualsLiteral("directoryLockId")) {
+          hasDirectoryLockId = true;
+          return true;
+        }
+        return true;
+      }));
+
+  bool exclusive = StaticPrefs::storage_sqlite_exclusiveLock_enabled();
+
+  const char* const vfs = hasKey               ? obfsvfs::GetVFSName()
+                          : hasDirectoryLockId ? quotavfs::GetVFSName()
+                                               : basevfs::GetVFSName(exclusive);
+
+  int srv = ::sqlite3_open_v2(spec.get(), &mDBConn, mFlags, vfs);
+  if (srv != SQLITE_OK) {
+    mDBConn = nullptr;
+    rv = convertResultCode(srv);
+    RecordOpenStatus(rv);
+    return rv;
+  }
+
+  rv = initializeInternal();
+  RecordOpenStatus(rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult Connection::initializeInternal() {
+  MOZ_ASSERT(mDBConn);
+  auto guard = MakeScopeExit([&]() { initializeFailed(); });
+
+  mConnectionClosed = false;
+
+#ifdef MOZ_SQLITE_FTS3_TOKENIZER
+  DebugOnly<int> srv2 =
+      ::sqlite3_db_config(mDBConn, SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, 1, 0);
+  MOZ_ASSERT(srv2 == SQLITE_OK,
+             "SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER should be enabled");
+#endif
+
+  // Properly wrap the database handle's mutex.
+  sharedDBMutex.initWithMutex(sqlite3_db_mutex(mDBConn));
+
+  // SQLite tracing can slow down queries (especially long queries)
+  // significantly. Don't trace unless the user is actively monitoring SQLite.
+  if (MOZ_LOG_TEST(gStorageLog, LogLevel::Debug)) {
+    ::sqlite3_trace_v2(mDBConn, SQLITE_TRACE_STMT | SQLITE_TRACE_PROFILE,
+                       tracefunc, this);
+
+    MOZ_LOG(
+        gStorageLog, LogLevel::Debug,
+        ("Opening connection to '%s' (%p)", mTelemetryFilename.get(), this));
+  }
+
+  int64_t pageSize = Service::kDefaultPageSize;
+
+  // Set page_size to the preferred default value.  This is effective only if
+  // the database has just been created, otherwise, if the database does not
+  // use WAL journal mode, a VACUUM operation will updated its page_size.
+  nsAutoCString pageSizeQuery(MOZ_STORAGE_UNIQUIFY_QUERY_STR
+                              "PRAGMA page_size = ");
+  pageSizeQuery.AppendInt(pageSize);
+  int srv = executeSql(mDBConn, pageSizeQuery.get());
+  if (srv != SQLITE_OK) {
+    return convertResultCode(srv);
+  }
+
+  // Setting the cache_size forces the database open, verifying if it is valid
+  // or corrupt.  So this is executed regardless it being actually needed.
+  // The cache_size is calculated from the actual page_size, to save memory.
+  nsAutoCString cacheSizeQuery(MOZ_STORAGE_UNIQUIFY_QUERY_STR
+                               "PRAGMA cache_size = ");
+  cacheSizeQuery.AppendInt(-MAX_CACHE_SIZE_KIBIBYTES);
+  srv = executeSql(mDBConn, cacheSizeQuery.get());
+  if (srv != SQLITE_OK) {
+    return convertResultCode(srv);
+  }
+
+  // Register our built-in SQL functions.
+  srv = registerFunctions(mDBConn);
+  if (srv != SQLITE_OK) {
+    return convertResultCode(srv);
+  }
+
+  // Register our built-in SQL collating sequences.
+  srv = registerCollations(mDBConn, mStorageService);
+  if (srv != SQLITE_OK) {
+    return convertResultCode(srv);
+  }
+
+  // Set the default synchronous value. Each consumer can switch this
+  // accordingly to their needs.
+#if defined(ANDROID)
+  // Android prefers synchronous = OFF for performance reasons.
+  Unused << ExecuteSimpleSQL("PRAGMA synchronous = OFF;"_ns);
+#else
+  // Normal is the suggested value for WAL journals.
+  Unused << ExecuteSimpleSQL("PRAGMA synchronous = NORMAL;"_ns);
+#endif
+
+  // Initialization succeeded, we can stop guarding for failures.
+  guard.release();
+  return NS_OK;
+}
+
+nsresult Connection::initializeOnAsyncThread(nsIFile* aStorageFile) {
+  MOZ_ASSERT(!IsOnCurrentSerialEventTarget(eventTargetOpenedOn));
+  nsresult rv = aStorageFile
+                    ? initialize(aStorageFile)
+                    : initialize(kMozStorageMemoryStorageKey, VoidCString());
+  if (NS_FAILED(rv)) {
+    // Shutdown the async thread, since initialization failed.
+    MutexAutoLock lockedScope(sharedAsyncExecutionMutex);
+    mAsyncExecutionThreadShuttingDown = true;
+    nsCOMPtr<nsIRunnable> event =
+        NewRunnableMethod("Connection::shutdownAsyncThread", this,
+                          &Connection::shutdownAsyncThread);
+    Unused << NS_DispatchToMainThread(event);
+  }
+  return rv;
+}
+
+void Connection::initializeFailed() {
+  {
+    MutexAutoLock lockedScope(sharedAsyncExecutionMutex);
+    mConnectionClosed = true;
+  }
+  MOZ_ALWAYS_TRUE(::sqlite3_close(mDBConn) == SQLITE_OK);
+  mDBConn = nullptr;
+  sharedDBMutex.destroy();
+}
+
+nsresult Connection::databaseElementExists(
+    enum DatabaseElementType aElementType, const nsACString& aElementName,
+    bool* _exists) {
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+  nsresult rv = ensureOperationSupported(SYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  // When constructing the query, make sure to SELECT the correct db's
+  // sqlite_master if the user is prefixing the element with a specific db. ex:
+  // sample.test
+  nsCString query("SELECT name FROM (SELECT * FROM ");
+  nsDependentCSubstring element;
+  int32_t ind = aElementName.FindChar('.');
+  if (ind == kNotFound) {
+    element.Assign(aElementName);
+  } else {
+    nsDependentCSubstring db(Substring(aElementName, 0, ind + 1));
+    element.Assign(Substring(aElementName, ind + 1, aElementName.Length()));
+    query.Append(db);
+  }
+  query.AppendLiteral(
+      "sqlite_master UNION ALL SELECT * FROM sqlite_temp_master) WHERE type = "
+      "'");
+
+  switch (aElementType) {
+    case INDEX:
+      query.AppendLiteral("index");
+      break;
+    case TABLE:
+      query.AppendLiteral("table");
+      break;
+  }
+  query.AppendLiteral("' AND name ='");
+  query.Append(element);
+  query.Append('\'');
+
+  sqlite3_stmt* stmt;
+  int srv = prepareStatement(mDBConn, query, &stmt);
+  if (srv != SQLITE_OK) {
+    RecordQueryStatus(srv);
+    return convertResultCode(srv);
+  }
+
+  srv = stepStatement(mDBConn, stmt);
+  // we just care about the return value from step
+  (void)::sqlite3_finalize(stmt);
+
+  RecordQueryStatus(srv);
+
+  if (srv == SQLITE_ROW) {
+    *_exists = true;
+    return NS_OK;
+  }
+  if (srv == SQLITE_DONE) {
+    *_exists = false;
+    return NS_OK;
+  }
+
+  return convertResultCode(srv);
+}
+
+bool Connection::findFunctionByInstance(mozIStorageFunction* aInstance) {
+  sharedDBMutex.assertCurrentThreadOwns();
+
+  for (const auto& data : mFunctions.Values()) {
+    if (data.function == aInstance) {
+      return true;
+    }
+  }
+  return false;
+}
+
+/* static */
+int Connection::sProgressHelper(void* aArg) {
+  Connection* _this = static_cast<Connection*>(aArg);
+  return _this->progressHandler();
+}
+
+int Connection::progressHandler() {
+  sharedDBMutex.assertCurrentThreadOwns();
+  if (mProgressHandler) {
+    bool result;
+    nsresult rv = mProgressHandler->OnProgress(this, &result);
+    if (NS_FAILED(rv)) return 0;  // Don't break request
+    return result ? 1 : 0;
+  }
+  return 0;
+}
+
+nsresult Connection::setClosedState() {
+  // Flag that we are shutting down the async thread, so that
+  // getAsyncExecutionTarget knows not to expose/create the async thread.
+  MutexAutoLock lockedScope(sharedAsyncExecutionMutex);
+  NS_ENSURE_FALSE(mAsyncExecutionThreadShuttingDown, NS_ERROR_UNEXPECTED);
+
+  mAsyncExecutionThreadShuttingDown = true;
+
+  // Set the property to null before closing the connection, otherwise the
+  // other functions in the module may try to use the connection after it is
+  // closed.
+  mDBConn = nullptr;
+
+  return NS_OK;
+}
+
+bool Connection::operationSupported(ConnectionOperation aOperationType) {
+  if (aOperationType == ASYNCHRONOUS) {
+    // Async operations are supported for all connections, on any thread.
+    return true;
+  }
+  // Sync operations are supported for sync connections (on any thread), and
+  // async connections on a background thread.
+  MOZ_ASSERT(aOperationType == SYNCHRONOUS);
+  return mSupportedOperations == SYNCHRONOUS || !NS_IsMainThread();
+}
+
+nsresult Connection::ensureOperationSupported(
+    ConnectionOperation aOperationType) {
+  if (NS_WARN_IF(!operationSupported(aOperationType))) {
+#ifdef DEBUG
+    if (NS_IsMainThread()) {
+      nsCOMPtr<nsIXPConnect> xpc = nsIXPConnect::XPConnect();
+      Unused << xpc->DebugDumpJSStack(false, false, false);
+    }
+#endif
+    MOZ_ASSERT(false,
+               "Don't use async connections synchronously on the main thread");
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+  return NS_OK;
+}
+
+bool Connection::isConnectionReadyOnThisThread() {
+  MOZ_ASSERT_IF(connectionReady(), !mConnectionClosed);
+  if (mAsyncExecutionThread && mAsyncExecutionThread->IsOnCurrentThread()) {
+    return true;
+  }
+  return connectionReady();
+}
+
+bool Connection::isClosing() {
+  MutexAutoLock lockedScope(sharedAsyncExecutionMutex);
+  return mAsyncExecutionThreadShuttingDown && !mConnectionClosed;
+}
+
+bool Connection::isClosed() {
+  MutexAutoLock lockedScope(sharedAsyncExecutionMutex);
+  return mConnectionClosed;
+}
+
+bool Connection::isClosed(MutexAutoLock& lock) { return mConnectionClosed; }
+
+bool Connection::isAsyncExecutionThreadAvailable() {
+  MOZ_ASSERT(IsOnCurrentSerialEventTarget(eventTargetOpenedOn));
+  return mAsyncExecutionThread && !mAsyncExecutionThreadShuttingDown;
+}
+
+void Connection::shutdownAsyncThread() {
+  MOZ_ASSERT(IsOnCurrentSerialEventTarget(eventTargetOpenedOn));
+  MOZ_ASSERT(mAsyncExecutionThread);
+  MOZ_ASSERT(mAsyncExecutionThreadShuttingDown);
+
+  MOZ_ALWAYS_SUCCEEDS(mAsyncExecutionThread->Shutdown());
+  mAsyncExecutionThread = nullptr;
+}
+
+nsresult Connection::internalClose(sqlite3* aNativeConnection) {
+#ifdef DEBUG
+  {  // Make sure we have marked our async thread as shutting down.
+    MutexAutoLock lockedScope(sharedAsyncExecutionMutex);
+    MOZ_ASSERT(mAsyncExecutionThreadShuttingDown,
+               "Did not call setClosedState!");
+    MOZ_ASSERT(!isClosed(lockedScope), "Unexpected closed state");
+  }
+#endif  // DEBUG
+
+  if (MOZ_LOG_TEST(gStorageLog, LogLevel::Debug)) {
+    nsAutoCString leafName(":memory");
+    if (mDatabaseFile) (void)mDatabaseFile->GetNativeLeafName(leafName);
+    MOZ_LOG(gStorageLog, LogLevel::Debug,
+            ("Closing connection to '%s'", leafName.get()));
+  }
+
+  // At this stage, we may still have statements that need to be
+  // finalized. Attempt to close the database connection. This will
+  // always disconnect any virtual tables and cleanly finalize their
+  // internal statements. Once this is done, closing may fail due to
+  // unfinalized client statements, in which case we need to finalize
+  // these statements and close again.
+  {
+    MutexAutoLock lockedScope(sharedAsyncExecutionMutex);
+    mConnectionClosed = true;
+  }
+
+  // Nothing else needs to be done if we don't have a connection here.
+  if (!aNativeConnection) return NS_OK;
+
+  int srv = ::sqlite3_close(aNativeConnection);
+
+  if (srv == SQLITE_BUSY) {
+    {
+      // Nothing else should change the connection or statements status until we
+      // are done here.
+      SQLiteMutexAutoLock lockedScope(sharedDBMutex);
+      // We still have non-finalized statements. Finalize them.
+      sqlite3_stmt* stmt = nullptr;
+      while ((stmt = ::sqlite3_next_stmt(aNativeConnection, stmt))) {
+        MOZ_LOG(gStorageLog, LogLevel::Debug,
+                ("Auto-finalizing SQL statement '%s' (%p)", ::sqlite3_sql(stmt),
+                 stmt));
+
+#ifdef DEBUG
+        SmprintfPointer msg = ::mozilla::Smprintf(
+            "SQL statement '%s' (%p) should have been finalized before closing "
+            "the connection",
+            ::sqlite3_sql(stmt), stmt);
+        NS_WARNING(msg.get());
+#endif  // DEBUG
+
+        srv = ::sqlite3_finalize(stmt);
+
+#ifdef DEBUG
+        if (srv != SQLITE_OK) {
+          SmprintfPointer msg = ::mozilla::Smprintf(
+              "Could not finalize SQL statement (%p)", stmt);
+          NS_WARNING(msg.get());
+        }
+#endif  // DEBUG
+
+        // Ensure that the loop continues properly, whether closing has
+        // succeeded or not.
+        if (srv == SQLITE_OK) {
+          stmt = nullptr;
+        }
+      }
+      // Scope exiting will unlock the mutex before we invoke sqlite3_close()
+      // again, since Sqlite will try to acquire it.
+    }
+
+    // Now that all statements have been finalized, we
+    // should be able to close.
+    srv = ::sqlite3_close(aNativeConnection);
+    MOZ_ASSERT(false,
+               "Had to forcibly close the database connection because not all "
+               "the statements have been finalized.");
+  }
+
+  if (srv == SQLITE_OK) {
+    sharedDBMutex.destroy();
+  } else {
+    MOZ_ASSERT(false,
+               "sqlite3_close failed. There are probably outstanding "
+               "statements that are listed above!");
+  }
+
+  return convertResultCode(srv);
+}
+
+nsCString Connection::getFilename() { return mTelemetryFilename; }
+
+int Connection::stepStatement(sqlite3* aNativeConnection,
+                              sqlite3_stmt* aStatement) {
+  MOZ_ASSERT(aStatement);
+
+  AUTO_PROFILER_LABEL_DYNAMIC_CSTR("Connection::stepStatement", OTHER,
+                                   ::sqlite3_sql(aStatement));
+
+  bool checkedMainThread = false;
+  TimeStamp startTime = TimeStamp::Now();
+
+  // The connection may have been closed if the executing statement has been
+  // created and cached after a call to asyncClose() but before the actual
+  // sqlite3_close().  This usually happens when other tasks using cached
+  // statements are asynchronously scheduled for execution and any of them ends
+  // up after asyncClose. See bug 728653 for details.
+  if (!isConnectionReadyOnThisThread()) return SQLITE_MISUSE;
+
+  (void)::sqlite3_extended_result_codes(aNativeConnection, 1);
+
+  int srv;
+  while ((srv = ::sqlite3_step(aStatement)) == SQLITE_LOCKED_SHAREDCACHE) {
+    if (!checkedMainThread) {
+      checkedMainThread = true;
+      if (::NS_IsMainThread()) {
+        NS_WARNING("We won't allow blocking on the main thread!");
+        break;
+      }
+    }
+
+    srv = WaitForUnlockNotify(aNativeConnection);
+    if (srv != SQLITE_OK) {
+      break;
+    }
+
+    ::sqlite3_reset(aStatement);
+  }
+
+  // Report very slow SQL statements to Telemetry
+  TimeDuration duration = TimeStamp::Now() - startTime;
+  const uint32_t threshold = NS_IsMainThread()
+                                 ? Telemetry::kSlowSQLThresholdForMainThread
+                                 : Telemetry::kSlowSQLThresholdForHelperThreads;
+  if (duration.ToMilliseconds() >= threshold) {
+    nsDependentCString statementString(::sqlite3_sql(aStatement));
+    Telemetry::RecordSlowSQLStatement(
+        statementString, mTelemetryFilename,
+        static_cast<uint32_t>(duration.ToMilliseconds()));
+  }
+
+  (void)::sqlite3_extended_result_codes(aNativeConnection, 0);
+  // Drop off the extended result bits of the result code.
+  return srv & 0xFF;
+}
+
+int Connection::prepareStatement(sqlite3* aNativeConnection,
+                                 const nsCString& aSQL, sqlite3_stmt** _stmt) {
+  // We should not even try to prepare statements after the connection has
+  // been closed.
+  if (!isConnectionReadyOnThisThread()) return SQLITE_MISUSE;
+
+  bool checkedMainThread = false;
+
+  (void)::sqlite3_extended_result_codes(aNativeConnection, 1);
+
+  int srv;
+  while ((srv = ::sqlite3_prepare_v2(aNativeConnection, aSQL.get(), -1, _stmt,
+                                     nullptr)) == SQLITE_LOCKED_SHAREDCACHE) {
+    if (!checkedMainThread) {
+      checkedMainThread = true;
+      if (::NS_IsMainThread()) {
+        NS_WARNING("We won't allow blocking on the main thread!");
+        break;
+      }
+    }
+
+    srv = WaitForUnlockNotify(aNativeConnection);
+    if (srv != SQLITE_OK) {
+      break;
+    }
+  }
+
+  if (srv != SQLITE_OK) {
+    nsCString warnMsg;
+    warnMsg.AppendLiteral("The SQL statement '");
+    warnMsg.Append(aSQL);
+    warnMsg.AppendLiteral("' could not be compiled due to an error: ");
+    warnMsg.Append(::sqlite3_errmsg(aNativeConnection));
+
+#ifdef DEBUG
+    NS_WARNING(warnMsg.get());
+#endif
+    MOZ_LOG(gStorageLog, LogLevel::Error, ("%s", warnMsg.get()));
+  }
+
+  (void)::sqlite3_extended_result_codes(aNativeConnection, 0);
+  // Drop off the extended result bits of the result code.
+  int rc = srv & 0xFF;
+  // sqlite will return OK on a comment only string and set _stmt to nullptr.
+  // The callers of this function are used to only checking the return value,
+  // so it is safer to return an error code.
+  if (rc == SQLITE_OK && *_stmt == nullptr) {
+    return SQLITE_MISUSE;
+  }
+
+  return rc;
+}
+
+int Connection::executeSql(sqlite3* aNativeConnection, const char* aSqlString) {
+  if (!isConnectionReadyOnThisThread()) return SQLITE_MISUSE;
+
+  AUTO_PROFILER_LABEL_DYNAMIC_CSTR("Connection::executeSql", OTHER, aSqlString);
+
+  TimeStamp startTime = TimeStamp::Now();
+  int srv =
+      ::sqlite3_exec(aNativeConnection, aSqlString, nullptr, nullptr, nullptr);
+  RecordQueryStatus(srv);
+
+  // Report very slow SQL statements to Telemetry
+  TimeDuration duration = TimeStamp::Now() - startTime;
+  const uint32_t threshold = NS_IsMainThread()
+                                 ? Telemetry::kSlowSQLThresholdForMainThread
+                                 : Telemetry::kSlowSQLThresholdForHelperThreads;
+  if (duration.ToMilliseconds() >= threshold) {
+    nsDependentCString statementString(aSqlString);
+    Telemetry::RecordSlowSQLStatement(
+        statementString, mTelemetryFilename,
+        static_cast<uint32_t>(duration.ToMilliseconds()));
+  }
+
+  return srv;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsIInterfaceRequestor
+
+NS_IMETHODIMP
+Connection::GetInterface(const nsIID& aIID, void** _result) {
+  if (aIID.Equals(NS_GET_IID(nsIEventTarget))) {
+    nsIEventTarget* background = getAsyncExecutionTarget();
+    NS_IF_ADDREF(background);
+    *_result = background;
+    return NS_OK;
+  }
+  return NS_ERROR_NO_INTERFACE;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// mozIStorageConnection
+
+NS_IMETHODIMP
+Connection::Close() {
+  nsresult rv = ensureOperationSupported(SYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  return synchronousClose();
+}
+
+nsresult Connection::synchronousClose() {
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+#ifdef DEBUG
+  // Since we're accessing mAsyncExecutionThread, we need to be on the opener
+  // event target. We make this check outside of debug code below in
+  // setClosedState, but this is here to be explicit.
+  MOZ_ASSERT(IsOnCurrentSerialEventTarget(eventTargetOpenedOn));
+#endif  // DEBUG
+
+  // Make sure we have not executed any asynchronous statements.
+  // If this fails, the mDBConn may be left open, resulting in a leak.
+  // We'll try to finalize the pending statements and close the connection.
+  if (isAsyncExecutionThreadAvailable()) {
+#ifdef DEBUG
+    if (NS_IsMainThread()) {
+      nsCOMPtr<nsIXPConnect> xpc = nsIXPConnect::XPConnect();
+      Unused << xpc->DebugDumpJSStack(false, false, false);
+    }
+#endif
+    MOZ_ASSERT(false,
+               "Close() was invoked on a connection that executed asynchronous "
+               "statements. "
+               "Should have used asyncClose().");
+    // Try to close the database regardless, to free up resources.
+    Unused << SpinningSynchronousClose();
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  // setClosedState nullifies our connection pointer, so we take a raw pointer
+  // off it, to pass it through the close procedure.
+  sqlite3* nativeConn = mDBConn;
+  nsresult rv = setClosedState();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return internalClose(nativeConn);
+}
+
+NS_IMETHODIMP
+Connection::SpinningSynchronousClose() {
+  nsresult rv = ensureOperationSupported(SYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  if (!IsOnCurrentSerialEventTarget(eventTargetOpenedOn)) {
+    return NS_ERROR_NOT_SAME_THREAD;
+  }
+
+  // As currently implemented, we can't spin to wait for an existing AsyncClose.
+  // Our only existing caller will never have called close; assert if misused
+  // so that no new callers assume this works after an AsyncClose.
+  MOZ_DIAGNOSTIC_ASSERT(connectionReady());
+  if (!connectionReady()) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  RefPtr<CloseListener> listener = new CloseListener();
+  rv = AsyncClose(listener);
+  NS_ENSURE_SUCCESS(rv, rv);
+  MOZ_ALWAYS_TRUE(
+      SpinEventLoopUntil("storage::Connection::SpinningSynchronousClose"_ns,
+                         [&]() { return listener->mClosed; }));
+  MOZ_ASSERT(isClosed(), "The connection should be closed at this point");
+
+  return rv;
+}
+
+NS_IMETHODIMP
+Connection::AsyncClose(mozIStorageCompletionCallback* aCallback) {
+  NS_ENSURE_TRUE(NS_IsMainThread(), NS_ERROR_NOT_SAME_THREAD);
+  // Check if AsyncClose or Close were already invoked.
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(ASYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  // The two relevant factors at this point are whether we have a database
+  // connection and whether we have an async execution thread.  Here's what the
+  // states mean and how we handle them:
+  //
+  // - (mDBConn && asyncThread): The expected case where we are either an
+  //   async connection or a sync connection that has been used asynchronously.
+  //   Either way the caller must call us and not Close().  Nothing surprising
+  //   about this.  We'll dispatch AsyncCloseConnection to the already-existing
+  //   async thread.
+  //
+  // - (mDBConn && !asyncThread): A somewhat unusual case where the caller
+  //   opened the connection synchronously and was planning to use it
+  //   asynchronously, but never got around to using it asynchronously before
+  //   needing to shutdown.  This has been observed to happen for the cookie
+  //   service in a case where Firefox shuts itself down almost immediately
+  //   after startup (for unknown reasons).  In the Firefox shutdown case,
+  //   we may also fail to create a new async execution thread if one does not
+  //   already exist.  (nsThreadManager will refuse to create new threads when
+  //   it has already been told to shutdown.)  As such, we need to handle a
+  //   failure to create the async execution thread by falling back to
+  //   synchronous Close() and also dispatching the completion callback because
+  //   at least Places likes to spin a nested event loop that depends on the
+  //   callback being invoked.
+  //
+  //   Note that we have considered not trying to spin up the async execution
+  //   thread in this case if it does not already exist, but the overhead of
+  //   thread startup (if successful) is significantly less expensive than the
+  //   worst-case potential I/O hit of synchronously closing a database when we
+  //   could close it asynchronously.
+  //
+  // - (!mDBConn && asyncThread): This happens in some but not all cases where
+  //   OpenAsyncDatabase encountered a problem opening the database.  If it
+  //   happened in all cases AsyncInitDatabase would just shut down the thread
+  //   directly and we would avoid this case.  But it doesn't, so for simplicity
+  //   and consistency AsyncCloseConnection knows how to handle this and we
+  //   act like this was the (mDBConn && asyncThread) case in this method.
+  //
+  // - (!mDBConn && !asyncThread): The database was never successfully opened or
+  //   Close() or AsyncClose() has already been called (at least) once.  This is
+  //   undeniably a misuse case by the caller.  We could optimize for this
+  //   case by adding an additional check of mAsyncExecutionThread without using
+  //   getAsyncExecutionTarget() to avoid wastefully creating a thread just to
+  //   shut it down.  But this complicates the method for broken caller code
+  //   whereas we're still correct and safe without the special-case.
+  nsIEventTarget* asyncThread = getAsyncExecutionTarget();
+
+  // Create our callback event if we were given a callback.  This will
+  // eventually be dispatched in all cases, even if we fall back to Close() and
+  // the database wasn't open and we return an error.  The rationale is that
+  // no existing consumer checks our return value and several of them like to
+  // spin nested event loops until the callback fires.  Given that, it seems
+  // preferable for us to dispatch the callback in all cases.  (Except the
+  // wrong thread misuse case we bailed on up above.  But that's okay because
+  // that is statically wrong whereas these edge cases are dynamic.)
+  nsCOMPtr<nsIRunnable> completeEvent;
+  if (aCallback) {
+    completeEvent = newCompletionEvent(aCallback);
+  }
+
+  if (!asyncThread) {
+    // We were unable to create an async thread, so we need to fall back to
+    // using normal Close().  Since there is no async thread, Close() will
+    // not complain about that.  (Close() may, however, complain if the
+    // connection is closed, but that's okay.)
+    if (completeEvent) {
+      // Closing the database is more important than returning an error code
+      // about a failure to dispatch, especially because all existing native
+      // callers ignore our return value.
+      Unused << NS_DispatchToMainThread(completeEvent.forget());
+    }
+    MOZ_ALWAYS_SUCCEEDS(synchronousClose());
+    // Return a success inconditionally here, since Close() is unlikely to fail
+    // and we want to reassure the consumer that its callback will be invoked.
+    return NS_OK;
+  }
+
+  // If we're closing the connection during shutdown, and there is an
+  // interruptible statement running on the helper thread, issue a
+  // sqlite3_interrupt() to avoid crashing when that statement takes a long
+  // time (for example a vacuum).
+  if (AppShutdown::IsInOrBeyond(ShutdownPhase::AppShutdownConfirmed) &&
+      mInterruptible && mIsStatementOnHelperThreadInterruptible) {
+    MOZ_ASSERT(!isClosing(), "Must not be closing, see Interrupt()");
+    DebugOnly<nsresult> rv2 = Interrupt();
+    MOZ_ASSERT(NS_SUCCEEDED(rv2));
+  }
+
+  // setClosedState nullifies our connection pointer, so we take a raw pointer
+  // off it, to pass it through the close procedure.
+  sqlite3* nativeConn = mDBConn;
+  rv = setClosedState();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Create and dispatch our close event to the background thread.
+  nsCOMPtr<nsIRunnable> closeEvent =
+      new AsyncCloseConnection(this, nativeConn, completeEvent);
+  rv = asyncThread->Dispatch(closeEvent, NS_DISPATCH_NORMAL);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::AsyncClone(bool aReadOnly,
+                       mozIStorageCompletionCallback* aCallback) {
+  AUTO_PROFILER_LABEL("Connection::AsyncClone", OTHER);
+
+  NS_ENSURE_TRUE(NS_IsMainThread(), NS_ERROR_NOT_SAME_THREAD);
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(ASYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  if (!mDatabaseFile) return NS_ERROR_UNEXPECTED;
+
+  int flags = mFlags;
+  if (aReadOnly) {
+    // Turn off SQLITE_OPEN_READWRITE, and set SQLITE_OPEN_READONLY.
+    flags = (~SQLITE_OPEN_READWRITE & flags) | SQLITE_OPEN_READONLY;
+    // Turn off SQLITE_OPEN_CREATE.
+    flags = (~SQLITE_OPEN_CREATE & flags);
+  }
+
+  // The cloned connection will still implement the synchronous API, but throw
+  // if any synchronous methods are called on the main thread.
+  RefPtr<Connection> clone =
+      new Connection(mStorageService, flags, ASYNCHRONOUS, mTelemetryFilename);
+
+  RefPtr<AsyncInitializeClone> initEvent =
+      new AsyncInitializeClone(this, clone, aReadOnly, aCallback);
+  // Dispatch to our async thread, since the originating connection must remain
+  // valid and open for the whole cloning process.  This also ensures we are
+  // properly serialized with a `close` operation, rather than race with it.
+  nsCOMPtr<nsIEventTarget> target = getAsyncExecutionTarget();
+  if (!target) {
+    return NS_ERROR_UNEXPECTED;
+  }
+  return target->Dispatch(initEvent, NS_DISPATCH_NORMAL);
+}
+
+nsresult Connection::initializeClone(Connection* aClone, bool aReadOnly) {
+  nsresult rv;
+  if (!mStorageKey.IsEmpty()) {
+    rv = aClone->initialize(mStorageKey, mName);
+  } else if (mFileURL) {
+    rv = aClone->initialize(mFileURL);
+  } else {
+    rv = aClone->initialize(mDatabaseFile);
+  }
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  auto guard = MakeScopeExit([&]() { aClone->initializeFailed(); });
+
+  rv = aClone->SetDefaultTransactionType(mDefaultTransactionType);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Re-attach on-disk databases that were attached to the original connection.
+  {
+    nsCOMPtr<mozIStorageStatement> stmt;
+    rv = CreateStatement("PRAGMA database_list"_ns, getter_AddRefs(stmt));
+    NS_ENSURE_SUCCESS(rv, rv);
+    bool hasResult = false;
+    while (stmt && NS_SUCCEEDED(stmt->ExecuteStep(&hasResult)) && hasResult) {
+      nsAutoCString name;
+      rv = stmt->GetUTF8String(1, name);
+      if (NS_SUCCEEDED(rv) && !name.EqualsLiteral("main") &&
+          !name.EqualsLiteral("temp")) {
+        nsCString path;
+        rv = stmt->GetUTF8String(2, path);
+        if (NS_SUCCEEDED(rv) && !path.IsEmpty()) {
+          nsCOMPtr<mozIStorageStatement> attachStmt;
+          rv = aClone->CreateStatement("ATTACH DATABASE :path AS "_ns + name,
+                                       getter_AddRefs(attachStmt));
+          NS_ENSURE_SUCCESS(rv, rv);
+          rv = attachStmt->BindUTF8StringByName("path"_ns, path);
+          NS_ENSURE_SUCCESS(rv, rv);
+          rv = attachStmt->Execute();
+          NS_ENSURE_SUCCESS(rv, rv);
+        }
+      }
+    }
+  }
+
+  // Copy over pragmas from the original connection.
+  // LIMITATION WARNING!  Many of these pragmas are actually scoped to the
+  // schema ("main" and any other attached databases), and this implmentation
+  // fails to propagate them.  This is being addressed on trunk.
+  static const char* pragmas[] = {
+      "cache_size",  "temp_store",         "foreign_keys", "journal_size_limit",
+      "synchronous", "wal_autocheckpoint", "busy_timeout"};
+  for (auto& pragma : pragmas) {
+    // Read-only connections just need cache_size and temp_store pragmas.
+    if (aReadOnly && ::strcmp(pragma, "cache_size") != 0 &&
+        ::strcmp(pragma, "temp_store") != 0) {
+      continue;
+    }
+
+    nsAutoCString pragmaQuery("PRAGMA ");
+    pragmaQuery.Append(pragma);
+    nsCOMPtr<mozIStorageStatement> stmt;
+    rv = CreateStatement(pragmaQuery, getter_AddRefs(stmt));
+    NS_ENSURE_SUCCESS(rv, rv);
+    bool hasResult = false;
+    if (stmt && NS_SUCCEEDED(stmt->ExecuteStep(&hasResult)) && hasResult) {
+      pragmaQuery.AppendLiteral(" = ");
+      pragmaQuery.AppendInt(stmt->AsInt32(0));
+      rv = aClone->ExecuteSimpleSQL(pragmaQuery);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+  }
+
+  // Copy over temporary tables, triggers, and views from the original
+  // connections. Entities in `sqlite_temp_master` are only visible to the
+  // connection that created them.
+  if (!aReadOnly) {
+    rv = aClone->ExecuteSimpleSQL("BEGIN TRANSACTION"_ns);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    nsCOMPtr<mozIStorageStatement> stmt;
+    rv = CreateStatement(nsLiteralCString("SELECT sql FROM sqlite_temp_master "
+                                          "WHERE type IN ('table', 'view', "
+                                          "'index', 'trigger')"),
+                         getter_AddRefs(stmt));
+    // Propagate errors, because failing to copy triggers might cause schema
+    // coherency issues when writing to the database from the cloned connection.
+    NS_ENSURE_SUCCESS(rv, rv);
+    bool hasResult = false;
+    while (stmt && NS_SUCCEEDED(stmt->ExecuteStep(&hasResult)) && hasResult) {
+      nsAutoCString query;
+      rv = stmt->GetUTF8String(0, query);
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      // The `CREATE` SQL statements in `sqlite_temp_master` omit the `TEMP`
+      // keyword. We need to add it back, or we'll recreate temporary entities
+      // as persistent ones. `sqlite_temp_master` also holds `CREATE INDEX`
+      // statements, but those don't need `TEMP` keywords.
+      if (StringBeginsWith(query, "CREATE TABLE "_ns) ||
+          StringBeginsWith(query, "CREATE TRIGGER "_ns) ||
+          StringBeginsWith(query, "CREATE VIEW "_ns)) {
+        query.Replace(0, 6, "CREATE TEMP");
+      }
+
+      rv = aClone->ExecuteSimpleSQL(query);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    rv = aClone->ExecuteSimpleSQL("COMMIT"_ns);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // Copy any functions that have been added to this connection.
+  SQLiteMutexAutoLock lockedScope(sharedDBMutex);
+  for (const auto& entry : mFunctions) {
+    const nsACString& key = entry.GetKey();
+    Connection::FunctionInfo data = entry.GetData();
+
+    rv = aClone->CreateFunction(key, data.numArgs, data.function);
+    if (NS_FAILED(rv)) {
+      NS_WARNING("Failed to copy function to cloned connection");
+    }
+  }
+
+  // Load SQLite extensions that were on this connection.
+  // Copy into an array rather than holding the mutex while we load extensions.
+  nsTArray<nsCString> loadedExtensions;
+  {
+    MutexAutoLock lockedScope(sharedAsyncExecutionMutex);
+    AppendToArray(loadedExtensions, mLoadedExtensions);
+  }
+  for (const auto& extension : loadedExtensions) {
+    (void)aClone->LoadExtension(extension, nullptr);
+  }
+
+  guard.release();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::Clone(bool aReadOnly, mozIStorageConnection** _connection) {
+  MOZ_ASSERT(IsOnCurrentSerialEventTarget(eventTargetOpenedOn));
+
+  AUTO_PROFILER_LABEL("Connection::Clone", OTHER);
+
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(SYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  int flags = mFlags;
+  if (aReadOnly) {
+    // Turn off SQLITE_OPEN_READWRITE, and set SQLITE_OPEN_READONLY.
+    flags = (~SQLITE_OPEN_READWRITE & flags) | SQLITE_OPEN_READONLY;
+    // Turn off SQLITE_OPEN_CREATE.
+    flags = (~SQLITE_OPEN_CREATE & flags);
+  }
+
+  RefPtr<Connection> clone =
+      new Connection(mStorageService, flags, mSupportedOperations,
+                     mTelemetryFilename, mInterruptible);
+
+  rv = initializeClone(clone, aReadOnly);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  NS_IF_ADDREF(*_connection = clone);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::Interrupt() {
+  MOZ_ASSERT(mInterruptible, "Interrupt method not allowed");
+  MOZ_ASSERT_IF(SYNCHRONOUS == mSupportedOperations,
+                !IsOnCurrentSerialEventTarget(eventTargetOpenedOn));
+  MOZ_ASSERT_IF(ASYNCHRONOUS == mSupportedOperations,
+                IsOnCurrentSerialEventTarget(eventTargetOpenedOn));
+
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  if (isClosing()) {  // Closing already in asynchronous case
+    return NS_OK;
+  }
+
+  {
+    // As stated on https://www.sqlite.org/c3ref/interrupt.html,
+    // it is not safe to call sqlite3_interrupt() when
+    // database connection is closed or might close before
+    // sqlite3_interrupt() returns.
+    MutexAutoLock lockedScope(sharedAsyncExecutionMutex);
+    if (!isClosed(lockedScope)) {
+      MOZ_ASSERT(mDBConn);
+      ::sqlite3_interrupt(mDBConn);
+    }
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::AsyncVacuum(mozIStorageCompletionCallback* aCallback,
+                        bool aUseIncremental, int32_t aSetPageSize) {
+  NS_ENSURE_TRUE(NS_IsMainThread(), NS_ERROR_NOT_SAME_THREAD);
+  // Abort if we're shutting down.
+  if (AppShutdown::IsInOrBeyond(ShutdownPhase::AppShutdownConfirmed)) {
+    return NS_ERROR_ABORT;
+  }
+  // Check if AsyncClose or Close were already invoked.
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(ASYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  nsIEventTarget* asyncThread = getAsyncExecutionTarget();
+  if (!asyncThread) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  // Create and dispatch our vacuum event to the background thread.
+  nsCOMPtr<nsIRunnable> vacuumEvent =
+      new AsyncVacuumEvent(this, aCallback, aUseIncremental, aSetPageSize);
+  rv = asyncThread->Dispatch(vacuumEvent, NS_DISPATCH_NORMAL);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::GetDefaultPageSize(int32_t* _defaultPageSize) {
+  *_defaultPageSize = Service::kDefaultPageSize;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::GetConnectionReady(bool* _ready) {
+  MOZ_ASSERT(IsOnCurrentSerialEventTarget(eventTargetOpenedOn));
+  *_ready = connectionReady();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::GetDatabaseFile(nsIFile** _dbFile) {
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(ASYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  NS_IF_ADDREF(*_dbFile = mDatabaseFile);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::GetLastInsertRowID(int64_t* _id) {
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(SYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  sqlite_int64 id = ::sqlite3_last_insert_rowid(mDBConn);
+  *_id = id;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::GetAffectedRows(int32_t* _rows) {
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(SYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  *_rows = ::sqlite3_changes(mDBConn);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::GetLastError(int32_t* _error) {
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(SYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  *_error = ::sqlite3_errcode(mDBConn);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::GetLastErrorString(nsACString& _errorString) {
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(SYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  const char* serr = ::sqlite3_errmsg(mDBConn);
+  _errorString.Assign(serr);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::GetSchemaVersion(int32_t* _version) {
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(SYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  nsCOMPtr<mozIStorageStatement> stmt;
+  (void)CreateStatement("PRAGMA user_version"_ns, getter_AddRefs(stmt));
+  NS_ENSURE_TRUE(stmt, NS_ERROR_OUT_OF_MEMORY);
+
+  *_version = 0;
+  bool hasResult;
+  if (NS_SUCCEEDED(stmt->ExecuteStep(&hasResult)) && hasResult) {
+    *_version = stmt->AsInt32(0);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::SetSchemaVersion(int32_t aVersion) {
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(SYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  nsAutoCString stmt("PRAGMA user_version = "_ns);
+  stmt.AppendInt(aVersion);
+
+  return ExecuteSimpleSQL(stmt);
+}
+
+NS_IMETHODIMP
+Connection::CreateStatement(const nsACString& aSQLStatement,
+                            mozIStorageStatement** _stmt) {
+  NS_ENSURE_ARG_POINTER(_stmt);
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(SYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  RefPtr<Statement> statement(new Statement());
+  NS_ENSURE_TRUE(statement, NS_ERROR_OUT_OF_MEMORY);
+
+  rv = statement->initialize(this, mDBConn, aSQLStatement);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  Statement* rawPtr;
+  statement.forget(&rawPtr);
+  *_stmt = rawPtr;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::CreateAsyncStatement(const nsACString& aSQLStatement,
+                                 mozIStorageAsyncStatement** _stmt) {
+  NS_ENSURE_ARG_POINTER(_stmt);
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(ASYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  RefPtr<AsyncStatement> statement(new AsyncStatement());
+  NS_ENSURE_TRUE(statement, NS_ERROR_OUT_OF_MEMORY);
+
+  rv = statement->initialize(this, mDBConn, aSQLStatement);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  AsyncStatement* rawPtr;
+  statement.forget(&rawPtr);
+  *_stmt = rawPtr;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::ExecuteSimpleSQL(const nsACString& aSQLStatement) {
+  CHECK_MAINTHREAD_ABUSE();
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(SYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  int srv = executeSql(mDBConn, PromiseFlatCString(aSQLStatement).get());
+  return convertResultCode(srv);
+}
+
+NS_IMETHODIMP
+Connection::ExecuteAsync(
+    const nsTArray<RefPtr<mozIStorageBaseStatement>>& aStatements,
+    mozIStorageStatementCallback* aCallback,
+    mozIStoragePendingStatement** _handle) {
+  nsTArray<StatementData> stmts(aStatements.Length());
+  for (uint32_t i = 0; i < aStatements.Length(); i++) {
+    nsCOMPtr<StorageBaseStatementInternal> stmt =
+        do_QueryInterface(aStatements[i]);
+    NS_ENSURE_STATE(stmt);
+
+    // Obtain our StatementData.
+    StatementData data;
+    nsresult rv = stmt->getAsynchronousStatementData(data);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    NS_ASSERTION(stmt->getOwner() == this,
+                 "Statement must be from this database connection!");
+
+    // Now append it to our array.
+    stmts.AppendElement(data);
+  }
+
+  // Dispatch to the background
+  return AsyncExecuteStatements::execute(std::move(stmts), this, mDBConn,
+                                         aCallback, _handle);
+}
+
+NS_IMETHODIMP
+Connection::ExecuteSimpleSQLAsync(const nsACString& aSQLStatement,
+                                  mozIStorageStatementCallback* aCallback,
+                                  mozIStoragePendingStatement** _handle) {
+  NS_ENSURE_TRUE(NS_IsMainThread(), NS_ERROR_NOT_SAME_THREAD);
+
+  nsCOMPtr<mozIStorageAsyncStatement> stmt;
+  nsresult rv = CreateAsyncStatement(aSQLStatement, getter_AddRefs(stmt));
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  nsCOMPtr<mozIStoragePendingStatement> pendingStatement;
+  rv = stmt->ExecuteAsync(aCallback, getter_AddRefs(pendingStatement));
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  pendingStatement.forget(_handle);
+  return rv;
+}
+
+NS_IMETHODIMP
+Connection::TableExists(const nsACString& aTableName, bool* _exists) {
+  return databaseElementExists(TABLE, aTableName, _exists);
+}
+
+NS_IMETHODIMP
+Connection::IndexExists(const nsACString& aIndexName, bool* _exists) {
+  return databaseElementExists(INDEX, aIndexName, _exists);
+}
+
+NS_IMETHODIMP
+Connection::GetTransactionInProgress(bool* _inProgress) {
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(ASYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  SQLiteMutexAutoLock lockedScope(sharedDBMutex);
+  *_inProgress = transactionInProgress(lockedScope);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::GetDefaultTransactionType(int32_t* _type) {
+  *_type = mDefaultTransactionType;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::SetDefaultTransactionType(int32_t aType) {
+  NS_ENSURE_ARG_RANGE(aType, TRANSACTION_DEFERRED, TRANSACTION_EXCLUSIVE);
+  mDefaultTransactionType = aType;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::GetVariableLimit(int32_t* _limit) {
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  int limit = ::sqlite3_limit(mDBConn, SQLITE_LIMIT_VARIABLE_NUMBER, -1);
+  if (limit < 0) {
+    return NS_ERROR_UNEXPECTED;
+  }
+  *_limit = limit;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::BeginTransaction() {
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(SYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  SQLiteMutexAutoLock lockedScope(sharedDBMutex);
+  return beginTransactionInternal(lockedScope, mDBConn,
+                                  mDefaultTransactionType);
+}
+
+nsresult Connection::beginTransactionInternal(
+    const SQLiteMutexAutoLock& aProofOfLock, sqlite3* aNativeConnection,
+    int32_t aTransactionType) {
+  if (transactionInProgress(aProofOfLock)) {
+    return NS_ERROR_FAILURE;
+  }
+  nsresult rv;
+  switch (aTransactionType) {
+    case TRANSACTION_DEFERRED:
+      rv = convertResultCode(executeSql(aNativeConnection, "BEGIN DEFERRED"));
+      break;
+    case TRANSACTION_IMMEDIATE:
+      rv = convertResultCode(executeSql(aNativeConnection, "BEGIN IMMEDIATE"));
+      break;
+    case TRANSACTION_EXCLUSIVE:
+      rv = convertResultCode(executeSql(aNativeConnection, "BEGIN EXCLUSIVE"));
+      break;
+    default:
+      return NS_ERROR_ILLEGAL_VALUE;
+  }
+  return rv;
+}
+
+NS_IMETHODIMP
+Connection::CommitTransaction() {
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(SYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  SQLiteMutexAutoLock lockedScope(sharedDBMutex);
+  return commitTransactionInternal(lockedScope, mDBConn);
+}
+
+nsresult Connection::commitTransactionInternal(
+    const SQLiteMutexAutoLock& aProofOfLock, sqlite3* aNativeConnection) {
+  if (!transactionInProgress(aProofOfLock)) {
+    return NS_ERROR_UNEXPECTED;
+  }
+  nsresult rv =
+      convertResultCode(executeSql(aNativeConnection, "COMMIT TRANSACTION"));
+  return rv;
+}
+
+NS_IMETHODIMP
+Connection::RollbackTransaction() {
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(SYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  SQLiteMutexAutoLock lockedScope(sharedDBMutex);
+  return rollbackTransactionInternal(lockedScope, mDBConn);
+}
+
+nsresult Connection::rollbackTransactionInternal(
+    const SQLiteMutexAutoLock& aProofOfLock, sqlite3* aNativeConnection) {
+  if (!transactionInProgress(aProofOfLock)) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsresult rv =
+      convertResultCode(executeSql(aNativeConnection, "ROLLBACK TRANSACTION"));
+  return rv;
+}
+
+NS_IMETHODIMP
+Connection::CreateTable(const char* aTableName, const char* aTableSchema) {
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(SYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  SmprintfPointer buf =
+      ::mozilla::Smprintf("CREATE TABLE %s (%s)", aTableName, aTableSchema);
+  if (!buf) return NS_ERROR_OUT_OF_MEMORY;
+
+  int srv = executeSql(mDBConn, buf.get());
+
+  return convertResultCode(srv);
+}
+
+NS_IMETHODIMP
+Connection::CreateFunction(const nsACString& aFunctionName,
+                           int32_t aNumArguments,
+                           mozIStorageFunction* aFunction) {
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(ASYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  // Check to see if this function is already defined.  We only check the name
+  // because a function can be defined with the same body but different names.
+  SQLiteMutexAutoLock lockedScope(sharedDBMutex);
+  NS_ENSURE_FALSE(mFunctions.Contains(aFunctionName), NS_ERROR_FAILURE);
+
+  int srv = ::sqlite3_create_function(
+      mDBConn, nsPromiseFlatCString(aFunctionName).get(), aNumArguments,
+      SQLITE_ANY, aFunction, basicFunctionHelper, nullptr, nullptr);
+  if (srv != SQLITE_OK) return convertResultCode(srv);
+
+  FunctionInfo info = {aFunction, aNumArguments};
+  mFunctions.InsertOrUpdate(aFunctionName, info);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::RemoveFunction(const nsACString& aFunctionName) {
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(ASYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  SQLiteMutexAutoLock lockedScope(sharedDBMutex);
+  NS_ENSURE_TRUE(mFunctions.Get(aFunctionName, nullptr), NS_ERROR_FAILURE);
+
+  int srv = ::sqlite3_create_function(
+      mDBConn, nsPromiseFlatCString(aFunctionName).get(), 0, SQLITE_ANY,
+      nullptr, nullptr, nullptr, nullptr);
+  if (srv != SQLITE_OK) return convertResultCode(srv);
+
+  mFunctions.Remove(aFunctionName);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::SetProgressHandler(int32_t aGranularity,
+                               mozIStorageProgressHandler* aHandler,
+                               mozIStorageProgressHandler** _oldHandler) {
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(ASYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  // Return previous one
+  SQLiteMutexAutoLock lockedScope(sharedDBMutex);
+  NS_IF_ADDREF(*_oldHandler = mProgressHandler);
+
+  if (!aHandler || aGranularity <= 0) {
+    aHandler = nullptr;
+    aGranularity = 0;
+  }
+  mProgressHandler = aHandler;
+  ::sqlite3_progress_handler(mDBConn, aGranularity, sProgressHelper, this);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::RemoveProgressHandler(mozIStorageProgressHandler** _oldHandler) {
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(ASYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  // Return previous one
+  SQLiteMutexAutoLock lockedScope(sharedDBMutex);
+  NS_IF_ADDREF(*_oldHandler = mProgressHandler);
+
+  mProgressHandler = nullptr;
+  ::sqlite3_progress_handler(mDBConn, 0, nullptr, nullptr);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::SetGrowthIncrement(int32_t aChunkSize,
+                               const nsACString& aDatabaseName) {
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(SYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  // Bug 597215: Disk space is extremely limited on Android
+  // so don't preallocate space. This is also not effective
+  // on log structured file systems used by Android devices
+#if !defined(ANDROID) && !defined(MOZ_PLATFORM_MAEMO)
+  // Don't preallocate if less than 500MiB is available.
+  int64_t bytesAvailable;
+  rv = mDatabaseFile->GetDiskSpaceAvailable(&bytesAvailable);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (bytesAvailable < MIN_AVAILABLE_BYTES_PER_CHUNKED_GROWTH) {
+    return NS_ERROR_FILE_TOO_BIG;
+  }
+
+  int srv = ::sqlite3_file_control(
+      mDBConn,
+      aDatabaseName.Length() ? nsPromiseFlatCString(aDatabaseName).get()
+                             : nullptr,
+      SQLITE_FCNTL_CHUNK_SIZE, &aChunkSize);
+  if (srv == SQLITE_OK) {
+    mGrowthChunkSize = aChunkSize;
+  }
+#endif
+  return NS_OK;
+}
+
+int32_t Connection::RemovablePagesInFreeList(const nsACString& aSchemaName) {
+  int32_t freeListPagesCount = 0;
+  if (!isConnectionReadyOnThisThread()) {
+    MOZ_ASSERT(false, "Database connection is not ready");
+    return freeListPagesCount;
+  }
+  {
+    nsAutoCString query(MOZ_STORAGE_UNIQUIFY_QUERY_STR "PRAGMA ");
+    query.Append(aSchemaName);
+    query.AppendLiteral(".freelist_count");
+    nsCOMPtr<mozIStorageStatement> stmt;
+    DebugOnly<nsresult> rv = CreateStatement(query, getter_AddRefs(stmt));
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    bool hasResult = false;
+    if (stmt && NS_SUCCEEDED(stmt->ExecuteStep(&hasResult)) && hasResult) {
+      freeListPagesCount = stmt->AsInt32(0);
+    }
+  }
+  // If there's no chunk size set, any page is good to be removed.
+  if (mGrowthChunkSize == 0 || freeListPagesCount == 0) {
+    return freeListPagesCount;
+  }
+  int32_t pageSize;
+  {
+    nsAutoCString query(MOZ_STORAGE_UNIQUIFY_QUERY_STR "PRAGMA ");
+    query.Append(aSchemaName);
+    query.AppendLiteral(".page_size");
+    nsCOMPtr<mozIStorageStatement> stmt;
+    DebugOnly<nsresult> rv = CreateStatement(query, getter_AddRefs(stmt));
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    bool hasResult = false;
+    if (stmt && NS_SUCCEEDED(stmt->ExecuteStep(&hasResult)) && hasResult) {
+      pageSize = stmt->AsInt32(0);
+    } else {
+      MOZ_ASSERT(false, "Couldn't get page_size");
+      return 0;
+    }
+  }
+  return std::max(0, freeListPagesCount - (mGrowthChunkSize / pageSize));
+}
+
+NS_IMETHODIMP
+Connection::LoadExtension(const nsACString& aExtensionName,
+                          mozIStorageCompletionCallback* aCallback) {
+  AUTO_PROFILER_LABEL("Connection::LoadExtension", OTHER);
+
+  // This is a static list of extensions we can load.
+  // Please use lowercase ASCII names and keep this list alphabetically ordered.
+  static constexpr nsLiteralCString sSupportedExtensions[] = {
+      // clang-format off
+      "fts5"_ns,
+      // clang-format on
+  };
+  if (std::find(std::begin(sSupportedExtensions),
+                std::end(sSupportedExtensions),
+                aExtensionName) == std::end(sSupportedExtensions)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  int srv = ::sqlite3_db_config(mDBConn, SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION,
+                                1, nullptr);
+  if (srv != SQLITE_OK) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  // Track the loaded extension for later connection cloning operations.
+  {
+    MutexAutoLock lockedScope(sharedAsyncExecutionMutex);
+    if (!mLoadedExtensions.EnsureInserted(aExtensionName)) {
+      // Already loaded, bail out but issue a warning.
+      NS_WARNING(nsPrintfCString(
+                     "Tried to register '%s' SQLite extension multiple times!",
+                     PromiseFlatCString(aExtensionName).get())
+                     .get());
+      return NS_OK;
+    }
+  }
+
+  nsAutoCString entryPoint("sqlite3_");
+  entryPoint.Append(aExtensionName);
+  entryPoint.AppendLiteral("_init");
+
+  RefPtr<Runnable> loadTask = NS_NewRunnableFunction(
+      "mozStorageConnection::LoadExtension",
+      [this, self = RefPtr(this), entryPoint,
+       callback = RefPtr(aCallback)]() mutable {
+        MOZ_ASSERT(
+            !NS_IsMainThread() ||
+                (operationSupported(Connection::SYNCHRONOUS) &&
+                 eventTargetOpenedOn == GetMainThreadSerialEventTarget()),
+            "Should happen on main-thread only for synchronous connections "
+            "opened on the main thread");
+#ifdef MOZ_FOLD_LIBS
+        int srv = ::sqlite3_load_extension(mDBConn,
+                                           MOZ_DLL_PREFIX "nss3" MOZ_DLL_SUFFIX,
+                                           entryPoint.get(), nullptr);
+#else
+        int srv = ::sqlite3_load_extension(
+            mDBConn, MOZ_DLL_PREFIX "mozsqlite3" MOZ_DLL_SUFFIX,
+            entryPoint.get(), nullptr);
+#endif
+        if (!callback) {
+          return;
+        };
+        RefPtr<Runnable> callbackTask = NS_NewRunnableFunction(
+            "mozStorageConnection::LoadExtension_callback",
+            [callback = std::move(callback), srv]() {
+              (void)callback->Complete(convertResultCode(srv), nullptr);
+            });
+        if (IsOnCurrentSerialEventTarget(eventTargetOpenedOn)) {
+          MOZ_ALWAYS_SUCCEEDS(callbackTask->Run());
+        } else {
+          // Redispatch the callback to the calling thread.
+          MOZ_ALWAYS_SUCCEEDS(eventTargetOpenedOn->Dispatch(
+              callbackTask.forget(), NS_DISPATCH_NORMAL));
+        }
+      });
+
+  if (NS_IsMainThread() && !operationSupported(Connection::SYNCHRONOUS)) {
+    // This is a main-thread call to an async-only connection, thus we should
+    // load the library in the helper thread.
+    nsIEventTarget* helperThread = getAsyncExecutionTarget();
+    if (!helperThread) {
+      return NS_ERROR_NOT_INITIALIZED;
+    }
+    MOZ_ALWAYS_SUCCEEDS(
+        helperThread->Dispatch(loadTask.forget(), NS_DISPATCH_NORMAL));
+  } else {
+    // In any other case we just load the extension on the current thread.
+    MOZ_ALWAYS_SUCCEEDS(loadTask->Run());
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Connection::EnableModule(const nsACString& aModuleName) {
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(SYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  for (auto& gModule : gModules) {
+    struct Module* m = &gModule;
+    if (aModuleName.Equals(m->name)) {
+      int srv = m->registerFunc(mDBConn, m->name);
+      if (srv != SQLITE_OK) return convertResultCode(srv);
+
+      return NS_OK;
+    }
+  }
+
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+Connection::GetQuotaObjects(QuotaObject** aDatabaseQuotaObject,
+                            QuotaObject** aJournalQuotaObject) {
+  MOZ_ASSERT(aDatabaseQuotaObject);
+  MOZ_ASSERT(aJournalQuotaObject);
+
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(SYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  sqlite3_file* file;
+  int srv = ::sqlite3_file_control(mDBConn, nullptr, SQLITE_FCNTL_FILE_POINTER,
+                                   &file);
+  if (srv != SQLITE_OK) {
+    return convertResultCode(srv);
+  }
+
+  sqlite3_vfs* vfs;
+  srv =
+      ::sqlite3_file_control(mDBConn, nullptr, SQLITE_FCNTL_VFS_POINTER, &vfs);
+  if (srv != SQLITE_OK) {
+    return convertResultCode(srv);
+  }
+
+  bool obfusactingVFS = false;
+
+  {
+    const nsDependentCString vfsName{vfs->zName};
+
+    if (vfsName == obfsvfs::GetVFSName()) {
+      obfusactingVFS = true;
+    } else if (vfsName != quotavfs::GetVFSName()) {
+      NS_WARNING("Got unexpected vfs");
+      return NS_ERROR_FAILURE;
+    }
+  }
+
+  RefPtr<QuotaObject> databaseQuotaObject =
+      GetQuotaObject(file, obfusactingVFS);
+  if (NS_WARN_IF(!databaseQuotaObject)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  srv = ::sqlite3_file_control(mDBConn, nullptr, SQLITE_FCNTL_JOURNAL_POINTER,
+                               &file);
+  if (srv != SQLITE_OK) {
+    return convertResultCode(srv);
+  }
+
+  RefPtr<QuotaObject> journalQuotaObject = GetQuotaObject(file, obfusactingVFS);
+  if (NS_WARN_IF(!journalQuotaObject)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  databaseQuotaObject.forget(aDatabaseQuotaObject);
+  journalQuotaObject.forget(aJournalQuotaObject);
+  return NS_OK;
+}
+
+SQLiteMutex& Connection::GetSharedDBMutex() { return sharedDBMutex; }
+
+uint32_t Connection::GetTransactionNestingLevel(
+    const mozilla::storage::SQLiteMutexAutoLock& aProofOfLock) {
+  return mTransactionNestingLevel;
+}
+
+uint32_t Connection::IncreaseTransactionNestingLevel(
+    const mozilla::storage::SQLiteMutexAutoLock& aProofOfLock) {
+  return ++mTransactionNestingLevel;
+}
+
+uint32_t Connection::DecreaseTransactionNestingLevel(
+    const mozilla::storage::SQLiteMutexAutoLock& aProofOfLock) {
+  return --mTransactionNestingLevel;
+}
+
+NS_IMETHODIMP
+Connection::BackupToFileAsync(nsIFile* aDestinationFile,
+                              mozIStorageCompletionCallback* aCallback) {
+  NS_ENSURE_ARG(aDestinationFile);
+  NS_ENSURE_ARG(aCallback);
+  NS_ENSURE_TRUE(NS_IsMainThread(), NS_ERROR_NOT_SAME_THREAD);
+
+  // Abort if we're shutting down.
+  if (AppShutdown::IsInOrBeyond(ShutdownPhase::AppShutdownConfirmed)) {
+    return NS_ERROR_ABORT;
+  }
+  // Check if AsyncClose or Close were already invoked.
+  if (!connectionReady()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = ensureOperationSupported(ASYNCHRONOUS);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  nsIEventTarget* asyncThread = getAsyncExecutionTarget();
+  if (!asyncThread) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  // Create and dispatch our backup event to the execution thread.
+  nsCOMPtr<nsIRunnable> backupEvent =
+      new AsyncBackupDatabaseFile(this, mDBConn, aDestinationFile, aCallback);
+  rv = asyncThread->Dispatch(backupEvent, NS_DISPATCH_NORMAL);
+  return rv;
+}
+
+}  // namespace mozilla::storage
diff --git a/storage/mozStorageConnection.h b/storage/mozStorageConnection.h
new file mode 100644
index 0000000000..d059c9e8be
--- /dev/null
+++ b/storage/mozStorageConnection.h
@@ -0,0 +1,569 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_storage_Connection_h
+#define mozilla_storage_Connection_h
+
+#include "nsCOMPtr.h"
+#include "mozilla/Atomics.h"
+#include "mozilla/Mutex.h"
+#include "nsProxyRelease.h"
+#include "nsThreadUtils.h"
+#include "nsIInterfaceRequestor.h"
+
+#include "nsTHashMap.h"
+#include "nsTHashSet.h"
+#include "mozIStorageProgressHandler.h"
+#include "SQLiteMutex.h"
+#include "mozIStorageConnection.h"
+#include "mozStorageService.h"
+#include "mozIStorageAsyncConnection.h"
+#include "mozIStorageCompletionCallback.h"
+
+#include "mozilla/Attributes.h"
+
+#include "sqlite3.h"
+
+class nsIFile;
+class nsIFileURL;
+class nsIEventTarget;
+class nsISerialEventTarget;
+class nsIThread;
+
+namespace mozilla::storage {
+
+class Connection final : public mozIStorageConnection,
+                         public nsIInterfaceRequestor {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEASYNCCONNECTION
+  NS_DECL_MOZISTORAGECONNECTION
+  NS_DECL_NSIINTERFACEREQUESTOR
+
+  /**
+   * Indicates if a database operation is synchronous or asynchronous.
+   *
+   * - Async operations may be called from any thread for all connections.
+   * - Sync operations may be called from any thread for sync connections, and
+   *   from background threads for async connections.
+   */
+  enum ConnectionOperation { ASYNCHRONOUS, SYNCHRONOUS };
+
+  /**
+   * Structure used to describe user functions on the database connection.
+   */
+  struct FunctionInfo {
+    nsCOMPtr<mozIStorageFunction> function;
+    int32_t numArgs;
+  };
+
+  /**
+   * @param aService
+   *        Pointer to the storage service.  Held onto for the lifetime of the
+   *        connection.
+   * @param aFlags
+   *        The flags to pass to sqlite3_open_v2.
+   * @param aSupportedOperations
+   *        The operation types supported on this connection. All connections
+   *        implement both the async (`mozIStorageAsyncConnection`) and sync
+   *        (`mozIStorageConnection`) interfaces, but async connections may not
+   *        call sync operations from the main thread.
+   * @param aInterruptible
+   *        If |true|, the pending operations can be interrupted by invokind the
+   *        Interrupt() method.
+   *        If |false|, method Interrupt() must not be used.
+   * @param aIgnoreLockingMode
+   *        If |true|, ignore locks in force on the file. Only usable with
+   *        read-only connections. Defaults to false.
+   *        Use with extreme caution. If sqlite ignores locks, reads may fail
+   *        indicating database corruption (the database won't actually be
+   *        corrupt) or produce wrong results without any indication that has
+   *        happened.
+   */
+  Connection(Service* aService, int aFlags,
+             ConnectionOperation aSupportedOperations,
+             const nsCString& aTelemetryFilename, bool aInterruptible = false,
+             bool aIgnoreLockingMode = false);
+
+  /**
+   * Creates the connection to an in-memory database.
+   */
+  nsresult initialize(const nsACString& aStorageKey, const nsACString& aName);
+
+  /**
+   * Creates the connection to the database.
+   *
+   * @param aDatabaseFile
+   *        The nsIFile of the location of the database to open, or create if it
+   *        does not exist.
+   */
+  nsresult initialize(nsIFile* aDatabaseFile);
+
+  /**
+   * Creates the connection to the database.
+   *
+   * @param aFileURL
+   *        The nsIFileURL of the location of the database to open, or create if
+   * it does not exist.
+   */
+  nsresult initialize(nsIFileURL* aFileURL);
+
+  /**
+   * Same as initialize, but to be used on the async thread.
+   */
+  nsresult initializeOnAsyncThread(nsIFile* aStorageFile);
+
+  /**
+   * Fetches runtime status information for this connection.
+   *
+   * @param aStatusOption One of the SQLITE_DBSTATUS options defined at
+   *        http://www.sqlite.org/c3ref/c_dbstatus_options.html
+   * @param [optional] aMaxValue if provided, will be set to the highest
+   *        istantaneous value.
+   * @return the current value for the specified option.
+   */
+  int32_t getSqliteRuntimeStatus(int32_t aStatusOption,
+                                 int32_t* aMaxValue = nullptr);
+  /**
+   * Registers/unregisters a commit hook callback.
+   *
+   * @param aCallbackFn a callback function to be invoked on transactions
+   *        commit.  Pass nullptr to unregister the current callback.
+   * @param [optional] aData if provided, will be passed to the callback.
+   * @see http://sqlite.org/c3ref/commit_hook.html
+   */
+  void setCommitHook(int (*aCallbackFn)(void*), void* aData = nullptr) {
+    MOZ_ASSERT(mDBConn, "A connection must exist at this point");
+    ::sqlite3_commit_hook(mDBConn, aCallbackFn, aData);
+  };
+
+  /**
+   * Gets autocommit status.
+   */
+  bool getAutocommit() {
+    return mDBConn && static_cast<bool>(::sqlite3_get_autocommit(mDBConn));
+  };
+
+  /**
+   * Lazily creates and returns a background execution thread.  In the future,
+   * the thread may be re-claimed if left idle, so you should call this
+   * method just before you dispatch and not save the reference.
+   *
+   * This must be called from the opener thread.
+   *
+   * @return an event target suitable for asynchronous statement execution.
+   * @note This method will return null once AsyncClose() has been called.
+   */
+  nsIEventTarget* getAsyncExecutionTarget();
+
+  /**
+   * Mutex used by asynchronous statements to protect state.  The mutex is
+   * declared on the connection object because there is no contention between
+   * asynchronous statements (they are serialized on mAsyncExecutionThread).
+   * Currently protects:
+   *  - Connection.mAsyncExecutionThreadShuttingDown
+   *  - Connection.mConnectionClosed
+   *  - AsyncExecuteStatements.mCancelRequested
+   *  - Connection.mLoadedExtensions
+   */
+  Mutex sharedAsyncExecutionMutex MOZ_UNANNOTATED;
+
+  /**
+   * Wraps the mutex that SQLite gives us from sqlite3_db_mutex.  This is public
+   * because we already expose the sqlite3* native connection and proper
+   * operation of the deadlock detector requires everyone to use the same single
+   * SQLiteMutex instance for correctness.
+   */
+  SQLiteMutex sharedDBMutex;
+
+  /**
+   * References the event target this database was opened on.
+   */
+  const nsCOMPtr<nsISerialEventTarget> eventTargetOpenedOn;
+
+  /**
+   * Closes the SQLite database, and warns about any non-finalized statements.
+   */
+  nsresult internalClose(sqlite3* aNativeconnection);
+
+  /**
+   * Shuts down the passed-in async thread.
+   */
+  void shutdownAsyncThread();
+
+  /**
+   * Obtains the filename of the connection.  Useful for logging.
+   */
+  nsCString getFilename();
+
+  /**
+   * Creates an sqlite3 prepared statement object from an SQL string.
+   *
+   * @param aNativeConnection
+   *        The underlying Sqlite connection to prepare the statement with.
+   * @param aSQL
+   *        The SQL statement string to compile.
+   * @param _stmt
+   *        New sqlite3_stmt object.
+   * @return the result from sqlite3_prepare_v2.
+   */
+  int prepareStatement(sqlite3* aNativeConnection, const nsCString& aSQL,
+                       sqlite3_stmt** _stmt);
+
+  /**
+   * Performs a sqlite3_step on aStatement, while properly handling
+   * SQLITE_LOCKED when not on the main thread by waiting until we are notified.
+   *
+   * @param aNativeConnection
+   *        The underlying Sqlite connection to step the statement with.
+   * @param aStatement
+   *        A pointer to a sqlite3_stmt object.
+   * @return the result from sqlite3_step.
+   */
+  int stepStatement(sqlite3* aNativeConnection, sqlite3_stmt* aStatement);
+
+  /**
+   * Raw connection transaction management.
+   *
+   * @see BeginTransactionAs, CommitTransaction, RollbackTransaction.
+   */
+  nsresult beginTransactionInternal(
+      const SQLiteMutexAutoLock& aProofOfLock, sqlite3* aNativeConnection,
+      int32_t aTransactionType = TRANSACTION_DEFERRED);
+  nsresult commitTransactionInternal(const SQLiteMutexAutoLock& aProofOfLock,
+                                     sqlite3* aNativeConnection);
+  nsresult rollbackTransactionInternal(const SQLiteMutexAutoLock& aProofOfLock,
+                                       sqlite3* aNativeConnection);
+
+  /**
+   * Indicates if this database connection is open.
+   */
+  inline bool connectionReady() { return mDBConn != nullptr; }
+
+  /**
+   * Indicates if this database connection has an open transaction. Because
+   * multiple threads can execute statements on the same connection, this method
+   * requires proof that the caller is holding `sharedDBMutex`.
+   *
+   * Per the SQLite docs, `sqlite3_get_autocommit` returns 0 if autocommit mode
+   * is disabled. `BEGIN` disables autocommit mode, and `COMMIT`, `ROLLBACK`, or
+   * an automatic rollback re-enables it.
+   */
+  inline bool transactionInProgress(const SQLiteMutexAutoLock& aProofOfLock) {
+    return !getAutocommit();
+  }
+
+  /**
+   * Indicates if this database connection supports the given operation.
+   *
+   * @param  aOperationType
+   *         The operation type, sync or async.
+   * @return `true` if the operation is supported, `false` otherwise.
+   */
+  bool operationSupported(ConnectionOperation aOperationType);
+
+  /**
+   * Thread-aware version of connectionReady, results per caller's thread are:
+   *  - owner thread: Same as connectionReady().  True means we have a valid,
+   *    un-closed database connection and it's not going away until you invoke
+   *    Close() or AsyncClose().
+   *  - async thread: Returns true at all times because you can't schedule
+   *    runnables against the async thread after AsyncClose() has been called.
+   *    Therefore, the connection is still around if your code is running.
+   *  - any other thread: Race-prone Lies!  If you are main-thread code in
+   *    mozStorageService iterating over the list of connections, you need to
+   *    acquire the sharedAsyncExecutionMutex for the connection, invoke
+   *    connectionReady() while holding it, and then continue to hold it while
+   *    you do whatever you need to do.  This is because of off-main-thread
+   *    consumers like dom/cache and IndexedDB and other QuotaManager clients.
+   */
+  bool isConnectionReadyOnThisThread();
+
+  /**
+   * True if this connection has inited shutdown.
+   */
+  bool isClosing();
+
+  /**
+   * True if the underlying connection is closed.
+   * Any sqlite resources may be lost when this returns true, so nothing should
+   * try to use them.
+   * This locks on sharedAsyncExecutionMutex.
+   */
+  bool isClosed();
+
+  /**
+   * Same as isClosed(), but takes a proof-of-lock instead of locking
+   * internally.
+   */
+  bool isClosed(MutexAutoLock& lock);
+
+  /**
+   * True if the async execution thread is alive and able to be used (i.e., it
+   * is not in the process of shutting down.)
+   *
+   * This must be called from the opener thread.
+   */
+  bool isAsyncExecutionThreadAvailable();
+
+  nsresult initializeClone(Connection* aClone, bool aReadOnly);
+
+  /**
+   * Records a status from a sqlite statement.
+   *
+   * @param srv The sqlite result for the failure or SQLITE_OK.
+   */
+  void RecordQueryStatus(int srv);
+
+  /**
+   * Returns the number of pages in the free list that can be removed.
+   *
+   * A database may use chunked growth to reduce filesystem fragmentation, then
+   * Sqlite will allocate and release multiple pages in chunks. We want to
+   * preserve the chunked space to reduce the likelihood of fragmentation,
+   * releasing free pages only when there's a large amount of them. This can be
+   * used to decide if it's worth vacuuming the database and how many pages can
+   * be vacuumed in case of incremental vacuum.
+   * Note this returns 0, and asserts, in case of errors.
+   */
+  int32_t RemovablePagesInFreeList(const nsACString& aSchemaName);
+
+  /**
+   * Whether the statement currently running on the helper thread can be
+   * interrupted.
+   */
+  Atomic<bool> mIsStatementOnHelperThreadInterruptible;
+
+ private:
+  ~Connection();
+  nsresult initializeInternal();
+  void initializeFailed();
+
+  /**
+   * Records the status of an attempt to load a sqlite database to telemetry.
+   *
+   * @param rv The state of the load, success or failure.
+   */
+  void RecordOpenStatus(nsresult rv);
+
+  /**
+   * Sets the database into a closed state so no further actions can be
+   * performed.
+   *
+   * @note mDBConn is set to nullptr in this method.
+   */
+  nsresult setClosedState();
+
+  /**
+   * Helper for calls to sqlite3_exec. Reports long delays to Telemetry.
+   *
+   * @param aNativeConnection
+   *        The underlying Sqlite connection to execute the query with.
+   * @param aSqlString
+   *        SQL string to execute
+   * @return the result from sqlite3_exec.
+   */
+  int executeSql(sqlite3* aNativeConnection, const char* aSqlString);
+
+  /**
+   * Describes a certain primitive type in the database.
+   *
+   * Possible Values Are:
+   *  INDEX - To check for the existence of an index
+   *  TABLE - To check for the existence of a table
+   */
+  enum DatabaseElementType { INDEX, TABLE };
+
+  /**
+   * Determines if the specified primitive exists.
+   *
+   * @param aElementType
+   *        The type of element to check the existence of
+   * @param aElementName
+   *        The name of the element to check for
+   * @returns true if element exists, false otherwise
+   */
+  nsresult databaseElementExists(enum DatabaseElementType aElementType,
+                                 const nsACString& aElementName, bool* _exists);
+
+  bool findFunctionByInstance(mozIStorageFunction* aInstance);
+
+  static int sProgressHelper(void* aArg);
+  // Generic progress handler
+  // Dispatch call to registered progress handler,
+  // if there is one. Do nothing in other cases.
+  int progressHandler();
+
+  /**
+   * Like `operationSupported`, but throws (and, in a debug build, asserts) if
+   * the operation is unsupported.
+   */
+  nsresult ensureOperationSupported(ConnectionOperation aOperationType);
+
+  sqlite3* mDBConn;
+  nsCString mStorageKey;
+  nsCString mName;
+  nsCOMPtr<nsIFileURL> mFileURL;
+  nsCOMPtr<nsIFile> mDatabaseFile;
+
+  /**
+   * Lazily created thread for asynchronous statement execution.  Consumers
+   * should use getAsyncExecutionTarget rather than directly accessing this
+   * field.
+   *
+   * This must be modified only on the opener thread.
+   */
+  nsCOMPtr<nsIThread> mAsyncExecutionThread;
+
+  /**
+   * The filename that will be reported to telemetry for this connection. By
+   * default this will be the leaf of the path to the database file.
+   */
+  nsCString mTelemetryFilename;
+
+  /**
+   * Stores the default behavior for all transactions run on this connection.
+   */
+  mozilla::Atomic<int32_t> mDefaultTransactionType;
+
+  /**
+   * Used to trigger cleanup logic only the first time our refcount hits 1.  We
+   * may trigger a failsafe Close() that invokes SpinningSynchronousClose()
+   * which invokes AsyncClose() which may bump our refcount back up to 2 (and
+   * which will then fall back down to 1 again).  It's also possible that the
+   * Service may bump our refcount back above 1 if getConnections() runs before
+   * we invoke unregisterConnection().
+   */
+  mozilla::Atomic<bool> mDestroying;
+
+  /**
+   * Stores the mapping of a given function by name to its instance.  Access is
+   * protected by sharedDBMutex.
+   */
+  nsTHashMap<nsCStringHashKey, FunctionInfo> mFunctions;
+
+  /**
+   * Stores the registered progress handler for the database connection.  Access
+   * is protected by sharedDBMutex.
+   */
+  nsCOMPtr<mozIStorageProgressHandler> mProgressHandler;
+
+  // This is here for two reasons: 1) It's used to make sure that the
+  // connections do not outlive the service.  2) Our custom collating functions
+  // call its localeCompareStrings() method.
+  RefPtr<Service> mStorageService;
+
+  nsresult synchronousClose();
+
+  /**
+   * Stores the flags we passed to sqlite3_open_v2.
+   */
+  const int mFlags;
+
+  uint32_t mTransactionNestingLevel;
+
+  /**
+   * Indicates which operations are supported on this connection.
+   */
+  const ConnectionOperation mSupportedOperations;
+
+  /**
+   * Stores whether this connection is interruptible.
+   */
+  const bool mInterruptible;
+
+  /**
+   * Stores whether we should ask sqlite3_open_v2 to ignore locking.
+   */
+  const bool mIgnoreLockingMode;
+
+  /**
+   * Set to true by Close() or AsyncClose() prior to shutdown.
+   *
+   * If false, we guarantee both that the underlying sqlite3 database
+   * connection is still open and that getAsyncExecutionTarget() can
+   * return a thread. Once true, either the sqlite3 database
+   * connection is being shutdown or it has been
+   * shutdown. Additionally, once true, getAsyncExecutionTarget()
+   * returns null.
+   *
+   * This variable should be accessed while holding the
+   * sharedAsyncExecutionMutex.
+   */
+  bool mAsyncExecutionThreadShuttingDown;
+
+  /**
+   * Set to true just prior to calling sqlite3_close on the
+   * connection.
+   *
+   * This variable should be accessed while holding the
+   * sharedAsyncExecutionMutex.
+   */
+  bool mConnectionClosed;
+
+  /**
+   * Stores the growth increment chunk size, set through SetGrowthIncrement().
+   */
+  Atomic<int32_t> mGrowthChunkSize;
+
+  /**
+   * Stores a list of the SQLite extensions loaded for this connections.
+   * This is used to properly clone the connection.
+   * @note Hold sharedAsyncExecutionMutex while using this.
+   */
+  nsTHashSet<nsCString> mLoadedExtensions
+      MOZ_GUARDED_BY(sharedAsyncExecutionMutex);
+};
+
+/**
+ * A Runnable designed to call a mozIStorageCompletionCallback on
+ * the appropriate thread.
+ */
+class CallbackComplete final : public Runnable {
+ public:
+  /**
+   * @param aValue The result to pass to the callback. It must
+   *               already be owned by the main thread.
+   * @param aCallback The callback. It must already be owned by the
+   *                  main thread.
+   */
+  CallbackComplete(nsresult aStatus, nsISupports* aValue,
+                   already_AddRefed<mozIStorageCompletionCallback> aCallback)
+      : Runnable("storage::CallbackComplete"),
+        mStatus(aStatus),
+        mValue(aValue),
+        mCallback(aCallback) {}
+
+  NS_IMETHOD Run() override {
+    MOZ_ASSERT(NS_IsMainThread());
+    nsresult rv = mCallback->Complete(mStatus, mValue);
+
+    // Ensure that we release on the main thread
+    mValue = nullptr;
+    mCallback = nullptr;
+    return rv;
+  }
+
+ private:
+  nsresult mStatus;
+  nsCOMPtr<nsISupports> mValue;
+  // This is a RefPtr<T> and not a nsCOMPtr<T> because
+  // nsCOMP<T> would cause an off-main thread QI, which
+  // is not a good idea (and crashes XPConnect).
+  RefPtr<mozIStorageCompletionCallback> mCallback;
+};
+
+}  // namespace mozilla::storage
+
+/**
+ * Casting Connection to nsISupports is ambiguous.
+ * This method handles that.
+ */
+inline nsISupports* ToSupports(mozilla::storage::Connection* p) {
+  return NS_ISUPPORTS_CAST(mozIStorageAsyncConnection*, p);
+}
+
+#endif  // mozilla_storage_Connection_h
diff --git a/storage/mozStorageError.cpp b/storage/mozStorageError.cpp
new file mode 100644
index 0000000000..89beccac38
--- /dev/null
+++ b/storage/mozStorageError.cpp
@@ -0,0 +1,40 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozStorageError.h"
+
+namespace mozilla {
+namespace storage {
+
+////////////////////////////////////////////////////////////////////////////////
+//// Error
+
+Error::Error(int aResult, const char* aMessage)
+    : mResult(aResult), mMessage(aMessage) {}
+
+/**
+ * Note:  This object is only ever accessed on one thread at a time.  It it not
+ *        threadsafe, but it does need threadsafe AddRef and Release.
+ */
+NS_IMPL_ISUPPORTS(Error, mozIStorageError)
+
+////////////////////////////////////////////////////////////////////////////////
+//// mozIStorageError
+
+NS_IMETHODIMP
+Error::GetResult(int32_t* _result) {
+  *_result = mResult;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Error::GetMessage(nsACString& _message) {
+  _message = mMessage;
+  return NS_OK;
+}
+
+}  // namespace storage
+}  // namespace mozilla
diff --git a/storage/mozStorageError.h b/storage/mozStorageError.h
new file mode 100644
index 0000000000..07037fb418
--- /dev/null
+++ b/storage/mozStorageError.h
@@ -0,0 +1,34 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozStorageError_h
+#define mozStorageError_h
+
+#include "mozIStorageError.h"
+#include "nsString.h"
+#include "mozilla/Attributes.h"
+
+namespace mozilla {
+namespace storage {
+
+class Error final : public mozIStorageError {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEERROR
+
+  Error(int aResult, const char* aMessage);
+
+ private:
+  ~Error() {}
+
+  int mResult;
+  nsCString mMessage;
+};
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif  // mozStorageError_h
diff --git a/storage/mozStorageHelper.h b/storage/mozStorageHelper.h
new file mode 100644
index 0000000000..35ee54faa3
--- /dev/null
+++ b/storage/mozStorageHelper.h
@@ -0,0 +1,326 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef MOZSTORAGEHELPER_H
+#define MOZSTORAGEHELPER_H
+
+#include "nsCOMPtr.h"
+#include "nsString.h"
+#include "mozilla/DebugOnly.h"
+#include "mozilla/ScopeExit.h"
+
+#include "mozilla/storage/SQLiteMutex.h"
+#include "mozIStorageConnection.h"
+#include "mozIStorageStatement.h"
+#include "mozIStoragePendingStatement.h"
+#include "mozilla/DebugOnly.h"
+#include "nsCOMPtr.h"
+#include "nsError.h"
+
+/**
+ * This class wraps a transaction inside a given C++ scope, guaranteeing that
+ * the transaction will be completed even if you have an exception or
+ * return early.
+ *
+ * A common use is to create an instance with aCommitOnComplete = false
+ * (rollback), then call Commit() on this object manually when your function
+ * completes successfully.
+ *
+ * @note nested transactions are not supported by Sqlite, only nested
+ * savepoints, so if a transaction is already in progress, this object creates
+ * a nested savepoint to the existing transaction which is considered as
+ * anonymous savepoint itself. However, aType and aAsyncCommit are ignored
+ * in the case of nested savepoints.
+ *
+ * @param aConnection
+ *        The connection to create the transaction on.
+ * @param aCommitOnComplete
+ *        Controls whether the transaction is committed or rolled back when
+ *        this object goes out of scope.
+ * @param aType [optional]
+ *        The transaction type, as defined in mozIStorageConnection. Uses the
+ *        default transaction behavior for the connection if unspecified.
+ * @param aAsyncCommit [optional]
+ *        Whether commit should be executed asynchronously on the helper thread.
+ *        This is a special option introduced as an interim solution to reduce
+ *        main-thread fsyncs in Places.  Can only be used on main-thread.
+ *
+ *        WARNING: YOU SHOULD _NOT_ WRITE NEW MAIN-THREAD CODE USING THIS!
+ *
+ *        Notice that async commit might cause synchronous statements to fail
+ *        with SQLITE_BUSY.  A possible mitigation strategy is to use
+ *        PRAGMA busy_timeout, but notice that might cause main-thread jank.
+ *        Finally, if the database is using WAL journaling mode, other
+ *        connections won't see the changes done in async committed transactions
+ *        until commit is complete.
+ *
+ *        For all of the above reasons, this should only be used as an interim
+ *        solution and avoided completely if possible.
+ */
+class mozStorageTransaction {
+  using SQLiteMutexAutoLock = mozilla::storage::SQLiteMutexAutoLock;
+
+ public:
+  mozStorageTransaction(
+      mozIStorageConnection* aConnection, bool aCommitOnComplete,
+      int32_t aType = mozIStorageConnection::TRANSACTION_DEFAULT,
+      bool aAsyncCommit = false)
+      : mConnection(aConnection),
+        mType(aType),
+        mNestingLevel(0),
+        mHasTransaction(false),
+        mCommitOnComplete(aCommitOnComplete),
+        mCompleted(false),
+        mAsyncCommit(aAsyncCommit) {}
+
+  ~mozStorageTransaction() {
+    if (mConnection && mHasTransaction && !mCompleted) {
+      if (mCommitOnComplete) {
+        mozilla::DebugOnly<nsresult> rv = Commit();
+        NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
+                             "A transaction didn't commit correctly");
+      } else {
+        mozilla::DebugOnly<nsresult> rv = Rollback();
+        NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
+                             "A transaction didn't rollback correctly");
+      }
+    }
+  }
+
+  /**
+   * Starts the transaction.
+   */
+  nsresult Start() {
+    // XXX We should probably get rid of mHasTransaction and use mConnection
+    // for checking if a transaction has been started. However, we need to
+    // first stop supporting null mConnection and also move aConnection from
+    // the constructor to Start.
+    MOZ_DIAGNOSTIC_ASSERT(!mHasTransaction);
+
+    // XXX We should probably stop supporting null mConnection.
+
+    // XXX We should probably get rid of mCompleted and allow to start the
+    // transaction again if it was already committed or rolled back.
+    if (!mConnection || mCompleted) {
+      return NS_OK;
+    }
+
+    SQLiteMutexAutoLock lock(mConnection->GetSharedDBMutex());
+
+    // We nee to speculatively set the nesting level to be able to decide
+    // if this is a top level transaction and to be able to generate the
+    // savepoint name.
+    TransactionStarted(lock);
+
+    // If there's a failure we need to revert the speculatively set nesting
+    // level on the connection.
+    auto autoFinishTransaction =
+        mozilla::MakeScopeExit([&] { TransactionFinished(lock); });
+
+    nsAutoCString query;
+
+    if (TopLevelTransaction(lock)) {
+      query.Assign("BEGIN");
+      int32_t type = mType;
+      if (type == mozIStorageConnection::TRANSACTION_DEFAULT) {
+        MOZ_ALWAYS_SUCCEEDS(mConnection->GetDefaultTransactionType(&type));
+      }
+      switch (type) {
+        case mozIStorageConnection::TRANSACTION_IMMEDIATE:
+          query.AppendLiteral(" IMMEDIATE");
+          break;
+        case mozIStorageConnection::TRANSACTION_EXCLUSIVE:
+          query.AppendLiteral(" EXCLUSIVE");
+          break;
+        case mozIStorageConnection::TRANSACTION_DEFERRED:
+          query.AppendLiteral(" DEFERRED");
+          break;
+        default:
+          MOZ_ASSERT(false, "Unknown transaction type");
+      }
+    } else {
+      query.Assign("SAVEPOINT sp"_ns + IntToCString(mNestingLevel));
+    }
+
+    nsresult rv = mConnection->ExecuteSimpleSQL(query);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    autoFinishTransaction.release();
+
+    return NS_OK;
+  }
+
+  /**
+   * Commits the transaction if one is in progress. If one is not in progress,
+   * this is a NOP since the actual owner of the transaction outside of our
+   * scope is in charge of finally committing or rolling back the transaction.
+   */
+  nsresult Commit() {
+    // XXX Assert instead of returning NS_OK if the transaction hasn't been
+    // started.
+    if (!mConnection || mCompleted || !mHasTransaction) return NS_OK;
+
+    SQLiteMutexAutoLock lock(mConnection->GetSharedDBMutex());
+
+#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
+    MOZ_DIAGNOSTIC_ASSERT(CurrentTransaction(lock));
+#else
+    if (!CurrentTransaction(lock)) {
+      return NS_ERROR_NOT_AVAILABLE;
+    }
+#endif
+
+    mCompleted = true;
+
+    nsresult rv;
+
+    if (TopLevelTransaction(lock)) {
+      // TODO (bug 559659): this might fail with SQLITE_BUSY, but we don't
+      // handle it, thus the transaction might stay open until the next COMMIT.
+      if (mAsyncCommit) {
+        nsCOMPtr<mozIStoragePendingStatement> ps;
+        rv = mConnection->ExecuteSimpleSQLAsync("COMMIT"_ns, nullptr,
+                                                getter_AddRefs(ps));
+      } else {
+        rv = mConnection->ExecuteSimpleSQL("COMMIT"_ns);
+      }
+    } else {
+      rv = mConnection->ExecuteSimpleSQL("RELEASE sp"_ns +
+                                         IntToCString(mNestingLevel));
+    }
+
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    TransactionFinished(lock);
+
+    return NS_OK;
+  }
+
+  /**
+   * Rolls back the transaction if one is in progress. If one is not in
+   * progress, this is a NOP since the actual owner of the transaction outside
+   * of our scope is in charge of finally rolling back the transaction.
+   */
+  nsresult Rollback() {
+    // XXX Assert instead of returning NS_OK if the transaction hasn't been
+    // started.
+    if (!mConnection || mCompleted || !mHasTransaction) return NS_OK;
+
+    SQLiteMutexAutoLock lock(mConnection->GetSharedDBMutex());
+
+#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
+    MOZ_DIAGNOSTIC_ASSERT(CurrentTransaction(lock));
+#else
+    if (!CurrentTransaction(lock)) {
+      return NS_ERROR_NOT_AVAILABLE;
+    }
+#endif
+
+    mCompleted = true;
+
+    nsresult rv;
+
+    if (TopLevelTransaction(lock)) {
+      // TODO (bug 1062823): from Sqlite 3.7.11 on, rollback won't ever return
+      // a busy error, so this handling can be removed.
+      do {
+        rv = mConnection->ExecuteSimpleSQL("ROLLBACK"_ns);
+        if (rv == NS_ERROR_STORAGE_BUSY) (void)PR_Sleep(PR_INTERVAL_NO_WAIT);
+      } while (rv == NS_ERROR_STORAGE_BUSY);
+    } else {
+      const auto nestingLevelCString = IntToCString(mNestingLevel);
+      rv = mConnection->ExecuteSimpleSQL(
+          "ROLLBACK TO sp"_ns + nestingLevelCString + "; RELEASE sp"_ns +
+          nestingLevelCString);
+    }
+
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    TransactionFinished(lock);
+
+    return NS_OK;
+  }
+
+ protected:
+  void TransactionStarted(const SQLiteMutexAutoLock& aProofOfLock) {
+    MOZ_ASSERT(mConnection);
+    MOZ_ASSERT(!mHasTransaction);
+    MOZ_ASSERT(mNestingLevel == 0);
+    mHasTransaction = true;
+    mNestingLevel = mConnection->IncreaseTransactionNestingLevel(aProofOfLock);
+  }
+
+  bool CurrentTransaction(const SQLiteMutexAutoLock& aProofOfLock) const {
+    MOZ_ASSERT(mConnection);
+    MOZ_ASSERT(mHasTransaction);
+    MOZ_ASSERT(mNestingLevel > 0);
+    return mNestingLevel ==
+           mConnection->GetTransactionNestingLevel(aProofOfLock);
+  }
+
+  bool TopLevelTransaction(const SQLiteMutexAutoLock& aProofOfLock) const {
+    MOZ_ASSERT(mConnection);
+    MOZ_ASSERT(mHasTransaction);
+    MOZ_ASSERT(mNestingLevel > 0);
+    MOZ_ASSERT(CurrentTransaction(aProofOfLock));
+    return mNestingLevel == 1;
+  }
+
+  void TransactionFinished(const SQLiteMutexAutoLock& aProofOfLock) {
+    MOZ_ASSERT(mConnection);
+    MOZ_ASSERT(mHasTransaction);
+    MOZ_ASSERT(mNestingLevel > 0);
+    MOZ_ASSERT(CurrentTransaction(aProofOfLock));
+    mConnection->DecreaseTransactionNestingLevel(aProofOfLock);
+    mNestingLevel = 0;
+    mHasTransaction = false;
+  }
+
+  nsCOMPtr<mozIStorageConnection> mConnection;
+  int32_t mType;
+  uint32_t mNestingLevel;
+  bool mHasTransaction;
+  bool mCommitOnComplete;
+  bool mCompleted;
+  bool mAsyncCommit;
+};
+
+/**
+ * This class wraps a statement so that it is guaraneed to be reset when
+ * this object goes out of scope.
+ *
+ * Note that this always just resets the statement. If the statement doesn't
+ * need resetting, the reset operation is inexpensive.
+ */
+class MOZ_STACK_CLASS mozStorageStatementScoper {
+ public:
+  explicit mozStorageStatementScoper(mozIStorageStatement* aStatement)
+      : mStatement(aStatement) {}
+  ~mozStorageStatementScoper() {
+    if (mStatement) mStatement->Reset();
+  }
+
+  mozStorageStatementScoper(mozStorageStatementScoper&&) = default;
+  mozStorageStatementScoper& operator=(mozStorageStatementScoper&&) = default;
+  mozStorageStatementScoper(const mozStorageStatementScoper&) = delete;
+  mozStorageStatementScoper& operator=(const mozStorageStatementScoper&) =
+      delete;
+
+  /**
+   * Call this to make the statement not reset. You might do this if you know
+   * that the statement has been reset.
+   */
+  void Abandon() { mStatement = nullptr; }
+
+ protected:
+  nsCOMPtr<mozIStorageStatement> mStatement;
+};
+
+// Use this to make queries uniquely identifiable in telemetry
+// statistics, especially PRAGMAs.  We don't include __LINE__ so that
+// queries are stable in the face of source code changes.
+#define MOZ_STORAGE_UNIQUIFY_QUERY_STR "/* " __FILE__ " */ "
+
+#endif /* MOZSTORAGEHELPER_H */
diff --git a/storage/mozStoragePrivateHelpers.cpp b/storage/mozStoragePrivateHelpers.cpp
new file mode 100644
index 0000000000..ffda8d51e8
--- /dev/null
+++ b/storage/mozStoragePrivateHelpers.cpp
@@ -0,0 +1,253 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "sqlite3.h"
+
+#include "jsfriendapi.h"
+
+#include "nsPrintfCString.h"
+#include "nsString.h"
+#include "nsError.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/CondVar.h"
+#include "nsQueryObject.h"
+#include "nsThreadUtils.h"
+#include "nsJSUtils.h"
+
+#include "Variant.h"
+#include "mozStoragePrivateHelpers.h"
+#include "mozIStorageCompletionCallback.h"
+
+#include "mozilla/Logging.h"
+extern mozilla::LazyLogModule gStorageLog;
+
+namespace mozilla {
+namespace storage {
+
+bool isErrorCode(int aSQLiteResultCode) {
+  // Drop off the extended result bits of the result code.
+  int rc = aSQLiteResultCode & 0xFF;
+
+  return rc != SQLITE_OK && rc != SQLITE_ROW && rc != SQLITE_DONE;
+}
+
+nsresult convertResultCode(int aSQLiteResultCode) {
+  // Drop off the extended result bits of the result code.
+  int rc = aSQLiteResultCode & 0xFF;
+
+  switch (rc) {
+    case SQLITE_OK:
+    case SQLITE_ROW:
+    case SQLITE_DONE:
+      return NS_OK;
+    case SQLITE_CORRUPT:
+    case SQLITE_NOTADB:
+      return NS_ERROR_FILE_CORRUPTED;
+    case SQLITE_PERM:
+    case SQLITE_CANTOPEN:
+      return NS_ERROR_FILE_ACCESS_DENIED;
+    case SQLITE_BUSY:
+      return NS_ERROR_STORAGE_BUSY;
+    case SQLITE_LOCKED:
+      return NS_ERROR_FILE_IS_LOCKED;
+    case SQLITE_READONLY:
+      return NS_ERROR_FILE_READ_ONLY;
+    case SQLITE_IOERR:
+      return NS_ERROR_STORAGE_IOERR;
+    case SQLITE_FULL:
+    case SQLITE_TOOBIG:
+      return NS_ERROR_FILE_NO_DEVICE_SPACE;
+    case SQLITE_NOMEM:
+      return NS_ERROR_OUT_OF_MEMORY;
+    case SQLITE_MISUSE:
+      return NS_ERROR_UNEXPECTED;
+    case SQLITE_ABORT:
+    case SQLITE_INTERRUPT:
+      return NS_ERROR_ABORT;
+    case SQLITE_CONSTRAINT:
+      return NS_ERROR_STORAGE_CONSTRAINT;
+  }
+
+    // generic error
+#ifdef DEBUG
+  nsAutoCString message;
+  message.AppendLiteral("SQLite returned error code ");
+  message.AppendInt(rc);
+  message.AppendLiteral(" , Storage will convert it to NS_ERROR_FAILURE");
+  NS_WARNING_ASSERTION(rc == SQLITE_ERROR, message.get());
+#endif
+  return NS_ERROR_FAILURE;
+}
+
+void checkAndLogStatementPerformance(sqlite3_stmt* aStatement) {
+  // Check to see if the query performed sorting operations or not.  If it
+  // did, it may need to be optimized!
+  int count = ::sqlite3_stmt_status(aStatement, SQLITE_STMTSTATUS_SORT, 1);
+  if (count <= 0) return;
+
+  const char* sql = ::sqlite3_sql(aStatement);
+
+  // Check to see if this is marked to not warn
+  if (::strstr(sql, "/* do not warn (bug ")) return;
+
+  // CREATE INDEX always sorts (sorting is a necessary step in creating
+  // an index).  So ignore the warning there.
+  if (::strstr(sql, "CREATE INDEX") || ::strstr(sql, "CREATE UNIQUE INDEX"))
+    return;
+
+  nsAutoCString message("Suboptimal indexes for the SQL statement ");
+#ifdef MOZ_STORAGE_SORTWARNING_SQL_DUMP
+  message.Append('`');
+  message.Append(sql);
+  message.AppendLiteral("` [");
+  message.AppendInt(count);
+  message.AppendLiteral(" sort operation(s)]");
+#else
+  nsPrintfCString address("0x%p", aStatement);
+  message.Append(address);
+#endif
+  message.AppendLiteral(" (http://mzl.la/1FuID0j).");
+  NS_WARNING(message.get());
+}
+
+nsIVariant* convertJSValToVariant(JSContext* aCtx, const JS::Value& aValue) {
+  if (aValue.isInt32()) return new IntegerVariant(aValue.toInt32());
+
+  if (aValue.isDouble()) return new FloatVariant(aValue.toDouble());
+
+  if (aValue.isString()) {
+    nsAutoJSString value;
+    if (!value.init(aCtx, aValue.toString())) return nullptr;
+    return new TextVariant(value);
+  }
+
+  if (aValue.isBoolean()) return new IntegerVariant(aValue.isTrue() ? 1 : 0);
+
+  if (aValue.isNull()) return new NullVariant();
+
+  if (aValue.isObject()) {
+    JS::Rooted<JSObject*> obj(aCtx, &aValue.toObject());
+    // We only support Date instances, all others fail.
+    bool valid;
+    if (!js::DateIsValid(aCtx, obj, &valid) || !valid) return nullptr;
+
+    double msecd;
+    if (!js::DateGetMsecSinceEpoch(aCtx, obj, &msecd)) return nullptr;
+
+    msecd *= 1000.0;
+    int64_t msec = msecd;
+
+    return new IntegerVariant(msec);
+  }
+
+  return nullptr;
+}
+
+Variant_base* convertVariantToStorageVariant(nsIVariant* aVariant) {
+  RefPtr<Variant_base> variant = do_QueryObject(aVariant);
+  if (variant) {
+    // JS helpers already convert the JS representation to a Storage Variant,
+    // in such a case there's nothing left to do here, so just pass-through.
+    return variant;
+  }
+
+  if (!aVariant) return new NullVariant();
+
+  uint16_t dataType = aVariant->GetDataType();
+
+  switch (dataType) {
+    case nsIDataType::VTYPE_BOOL:
+    case nsIDataType::VTYPE_INT8:
+    case nsIDataType::VTYPE_INT16:
+    case nsIDataType::VTYPE_INT32:
+    case nsIDataType::VTYPE_UINT8:
+    case nsIDataType::VTYPE_UINT16:
+    case nsIDataType::VTYPE_UINT32:
+    case nsIDataType::VTYPE_INT64:
+    case nsIDataType::VTYPE_UINT64: {
+      int64_t v;
+      nsresult rv = aVariant->GetAsInt64(&v);
+      NS_ENSURE_SUCCESS(rv, nullptr);
+      return new IntegerVariant(v);
+    }
+    case nsIDataType::VTYPE_FLOAT:
+    case nsIDataType::VTYPE_DOUBLE: {
+      double v;
+      nsresult rv = aVariant->GetAsDouble(&v);
+      NS_ENSURE_SUCCESS(rv, nullptr);
+      return new FloatVariant(v);
+    }
+    case nsIDataType::VTYPE_CHAR:
+    case nsIDataType::VTYPE_CHAR_STR:
+    case nsIDataType::VTYPE_STRING_SIZE_IS:
+    case nsIDataType::VTYPE_UTF8STRING:
+    case nsIDataType::VTYPE_CSTRING: {
+      nsCString v;
+      nsresult rv = aVariant->GetAsAUTF8String(v);
+      NS_ENSURE_SUCCESS(rv, nullptr);
+      return new UTF8TextVariant(v);
+    }
+    case nsIDataType::VTYPE_WCHAR:
+    case nsIDataType::VTYPE_WCHAR_STR:
+    case nsIDataType::VTYPE_WSTRING_SIZE_IS:
+    case nsIDataType::VTYPE_ASTRING: {
+      nsString v;
+      nsresult rv = aVariant->GetAsAString(v);
+      NS_ENSURE_SUCCESS(rv, nullptr);
+      return new TextVariant(v);
+    }
+    case nsIDataType::VTYPE_ARRAY: {
+      uint16_t type;
+      nsIID iid;
+      uint32_t len;
+      void* rawArray;
+      // Note this copies the array data.
+      nsresult rv = aVariant->GetAsArray(&type, &iid, &len, &rawArray);
+      NS_ENSURE_SUCCESS(rv, nullptr);
+      if (type == nsIDataType::VTYPE_UINT8) {
+        std::pair<uint8_t*, int> v(static_cast<uint8_t*>(rawArray), len);
+        // Take ownership of the data avoiding a further copy.
+        return new AdoptedBlobVariant(v);
+      }
+      [[fallthrough]];
+    }
+    case nsIDataType::VTYPE_EMPTY:
+    case nsIDataType::VTYPE_EMPTY_ARRAY:
+    case nsIDataType::VTYPE_VOID:
+      return new NullVariant();
+    case nsIDataType::VTYPE_ID:
+    case nsIDataType::VTYPE_INTERFACE:
+    case nsIDataType::VTYPE_INTERFACE_IS:
+    default:
+      NS_WARNING("Unsupported variant type");
+      return nullptr;
+  }
+}
+
+namespace {
+class CallbackEvent : public Runnable {
+ public:
+  explicit CallbackEvent(mozIStorageCompletionCallback* aCallback)
+      : Runnable("storage::CallbackEvent"), mCallback(aCallback) {}
+
+  NS_IMETHOD Run() override {
+    (void)mCallback->Complete(NS_OK, nullptr);
+    return NS_OK;
+  }
+
+ private:
+  nsCOMPtr<mozIStorageCompletionCallback> mCallback;
+};
+}  // namespace
+already_AddRefed<nsIRunnable> newCompletionEvent(
+    mozIStorageCompletionCallback* aCallback) {
+  NS_ASSERTION(aCallback, "Passing a null callback is a no-no!");
+  nsCOMPtr<nsIRunnable> event = new CallbackEvent(aCallback);
+  return event.forget();
+}
+
+}  // namespace storage
+}  // namespace mozilla
diff --git a/storage/mozStoragePrivateHelpers.h b/storage/mozStoragePrivateHelpers.h
new file mode 100644
index 0000000000..9dca95392e
--- /dev/null
+++ b/storage/mozStoragePrivateHelpers.h
@@ -0,0 +1,154 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozStoragePrivateHelpers_h
+#define mozStoragePrivateHelpers_h
+
+/**
+ * This file contains convenience methods for mozStorage.
+ */
+
+#include "sqlite3.h"
+#include "nsISerialEventTarget.h"
+#include "nsIVariant.h"
+#include "nsError.h"
+#include "js/TypeDecls.h"
+#include "Variant.h"
+
+class mozIStorageCompletionCallback;
+class nsIRunnable;
+
+namespace mozilla {
+namespace storage {
+
+////////////////////////////////////////////////////////////////////////////////
+//// Macros
+
+#define ENSURE_INDEX_VALUE(aIndex, aCount) \
+  NS_ENSURE_TRUE(aIndex < aCount, NS_ERROR_INVALID_ARG)
+
+////////////////////////////////////////////////////////////////////////////////
+//// Functions
+
+/**
+ * Returns true if the given SQLite result is an error of come kind.
+ *
+ * @param aSQLiteResultCode
+ *        The SQLite return code to check.
+ * @returns true if the result represents an error.
+ */
+bool isErrorCode(int aSQLiteResultCode);
+
+/**
+ * Converts a SQLite return code to an nsresult return code.
+ *
+ * @param aSQLiteResultCode
+ *        The SQLite return code to convert.
+ * @returns the corresponding nsresult code for aSQLiteResultCode.
+ */
+nsresult convertResultCode(int aSQLiteResultCode);
+
+/**
+ * Checks the performance of a SQLite statement and logs a warning with
+ * NS_WARNING.  Currently this only checks the number of sort operations done
+ * on a statement, and if more than zero have been done, the statement can be
+ * made faster with the careful use of an index.
+ *
+ * @param aStatement
+ *        The sqlite3_stmt object to check.
+ */
+void checkAndLogStatementPerformance(sqlite3_stmt* aStatement);
+
+/**
+ * Convert the provided JS::Value into a variant representation if possible.
+ *
+ * @param aCtx
+ *        The JSContext the value is from.
+ * @param aValue
+ *        The JavaScript value to convert.  All primitive types are supported,
+ *        but only Date objects are supported from the Date family.  Date
+ *        objects are coerced to PRTime (nanoseconds since epoch) values.
+ * @return the variant if conversion was successful, nullptr if conversion
+ *         failed.  The caller is responsible for addref'ing if non-null.
+ */
+nsIVariant* convertJSValToVariant(JSContext* aCtx, const JS::Value& aValue);
+
+/**
+ * Convert a provided nsIVariant implementation to our own thread-safe
+ * refcounting implementation, if needed.
+ *
+ * @param aValue
+ *        The original nsIVariant to be converted.
+ * @return a thread-safe refcounting nsIVariant implementation.
+ */
+Variant_base* convertVariantToStorageVariant(nsIVariant* aVariant);
+
+/**
+ * Obtains an event that will notify a completion callback about completion.
+ *
+ * @param aCallback
+ *        The callback to be notified.
+ * @return an nsIRunnable that can be dispatched to the calling thread.
+ */
+already_AddRefed<nsIRunnable> newCompletionEvent(
+    mozIStorageCompletionCallback* aCallback);
+
+/**
+ * Utility method to get a Blob as a string value.  The string expects
+ * the interface exposed by nsAString/nsACString/etc.
+ */
+template <class T, class V>
+nsresult DoGetBlobAsString(T* aThis, uint32_t aIndex, V& aValue) {
+  typedef typename V::char_type char_type;
+
+  uint32_t size;
+  char_type* blob;
+  nsresult rv =
+      aThis->GetBlob(aIndex, &size, reinterpret_cast<uint8_t**>(&blob));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  aValue.Assign(blob, size / sizeof(char_type));
+  delete[] blob;
+  return NS_OK;
+}
+
+/**
+ * Utility method to bind a string value as a Blob.  The string expects
+ * the interface exposed by nsAString/nsACString/etc.
+ */
+template <class T, class V>
+nsresult DoBindStringAsBlobByName(T* aThis, const nsACString& aName,
+                                  const V& aValue) {
+  typedef typename V::char_type char_type;
+  return aThis->BindBlobByName(
+      aName, reinterpret_cast<const uint8_t*>(aValue.BeginReading()),
+      aValue.Length() * sizeof(char_type));
+}
+
+/**
+ * Utility method to bind a string value as a Blob.  The string expects
+ * the interface exposed by nsAString/nsACString/etc.
+ */
+template <class T, class V>
+nsresult DoBindStringAsBlobByIndex(T* aThis, uint32_t aIndex, const V& aValue) {
+  typedef typename V::char_type char_type;
+  return aThis->BindBlobByIndex(
+      aIndex, reinterpret_cast<const uint8_t*>(aValue.BeginReading()),
+      aValue.Length() * sizeof(char_type));
+}
+
+/**
+ * Utility function to check if a serial event target may run runnables
+ * on the current thread.
+ */
+inline bool IsOnCurrentSerialEventTarget(nsISerialEventTarget* aTarget) {
+  return aTarget->IsOnCurrentThread();
+}
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif  // mozStoragePrivateHelpers_h
diff --git a/storage/mozStorageResultSet.cpp b/storage/mozStorageResultSet.cpp
new file mode 100644
index 0000000000..8a0ae6abd3
--- /dev/null
+++ b/storage/mozStorageResultSet.cpp
@@ -0,0 +1,47 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozStorageRow.h"
+#include "mozStorageResultSet.h"
+
+namespace mozilla {
+namespace storage {
+
+////////////////////////////////////////////////////////////////////////////////
+//// ResultSet
+
+ResultSet::ResultSet() : mCurrentIndex(0) {}
+
+ResultSet::~ResultSet() { mData.Clear(); }
+
+nsresult ResultSet::add(mozIStorageRow* aRow) {
+  return mData.AppendObject(aRow) ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
+}
+
+/**
+ * Note:  This object is only ever accessed on one thread at a time.  It it not
+ *        threadsafe, but it does need threadsafe AddRef and Release.
+ */
+NS_IMPL_ISUPPORTS(ResultSet, mozIStorageResultSet)
+
+////////////////////////////////////////////////////////////////////////////////
+//// mozIStorageResultSet
+
+NS_IMETHODIMP
+ResultSet::GetNextRow(mozIStorageRow** _row) {
+  NS_ENSURE_ARG_POINTER(_row);
+
+  if (mCurrentIndex >= mData.Count()) {
+    // Just return null here
+    return NS_OK;
+  }
+
+  NS_ADDREF(*_row = mData.ObjectAt(mCurrentIndex++));
+  return NS_OK;
+}
+
+}  // namespace storage
+}  // namespace mozilla
diff --git a/storage/mozStorageResultSet.h b/storage/mozStorageResultSet.h
new file mode 100644
index 0000000000..0716504378
--- /dev/null
+++ b/storage/mozStorageResultSet.h
@@ -0,0 +1,52 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozStorageResultSet_h
+#define mozStorageResultSet_h
+
+#include "mozIStorageResultSet.h"
+#include "nsCOMArray.h"
+#include "mozilla/Attributes.h"
+class mozIStorageRow;
+
+namespace mozilla {
+namespace storage {
+
+class ResultSet final : public mozIStorageResultSet {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGERESULTSET
+
+  ResultSet();
+
+  /**
+   * Adds a tuple to this result set.
+   */
+  nsresult add(mozIStorageRow* aTuple);
+
+  /**
+   * @returns the number of rows this result set holds.
+   */
+  int32_t rows() const { return mData.Count(); }
+
+ private:
+  ~ResultSet();
+
+  /**
+   * Stores the current index of the active result set.
+   */
+  int32_t mCurrentIndex;
+
+  /**
+   * Stores the tuples.
+   */
+  nsCOMArray<mozIStorageRow> mData;
+};
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif  // mozStorageResultSet_h
diff --git a/storage/mozStorageRow.cpp b/storage/mozStorageRow.cpp
new file mode 100644
index 0000000000..bee49dfd85
--- /dev/null
+++ b/storage/mozStorageRow.cpp
@@ -0,0 +1,206 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozStorageRow.h"
+
+#include "nsString.h"
+
+#include "sqlite3.h"
+#include "mozStoragePrivateHelpers.h"
+#include "Variant.h"
+
+namespace mozilla {
+namespace storage {
+
+////////////////////////////////////////////////////////////////////////////////
+//// Row
+
+nsresult Row::initialize(sqlite3_stmt* aStatement) {
+  // Get the number of results
+  mNumCols = ::sqlite3_column_count(aStatement);
+
+  // Start copying over values
+  for (uint32_t i = 0; i < mNumCols; i++) {
+    // Store the value
+    nsIVariant* variant = nullptr;
+    int type = ::sqlite3_column_type(aStatement, i);
+    switch (type) {
+      case SQLITE_INTEGER:
+        variant = new IntegerVariant(::sqlite3_column_int64(aStatement, i));
+        break;
+      case SQLITE_FLOAT:
+        variant = new FloatVariant(::sqlite3_column_double(aStatement, i));
+        break;
+      case SQLITE_TEXT: {
+        const char16_t* value = static_cast<const char16_t*>(
+            ::sqlite3_column_text16(aStatement, i));
+        nsDependentString str(
+            value, ::sqlite3_column_bytes16(aStatement, i) / sizeof(char16_t));
+        variant = new TextVariant(str);
+        break;
+      }
+      case SQLITE_NULL:
+        variant = new NullVariant();
+        break;
+      case SQLITE_BLOB: {
+        const void* data = ::sqlite3_column_blob(aStatement, i);
+        int size = ::sqlite3_column_bytes(aStatement, i);
+        variant = new BlobVariant(std::pair<const void*, int>(data, size));
+        break;
+      }
+      default:
+        return NS_ERROR_UNEXPECTED;
+    }
+    NS_ENSURE_TRUE(variant, NS_ERROR_OUT_OF_MEMORY);
+
+    // Insert into our storage array
+    NS_ENSURE_TRUE(mData.InsertObjectAt(variant, i), NS_ERROR_OUT_OF_MEMORY);
+
+    // Associate the name (if any) with the index
+    const char* name = ::sqlite3_column_name(aStatement, i);
+    if (!name) break;
+    nsAutoCString colName(name);
+    mNameHashtable.InsertOrUpdate(colName, i);
+  }
+
+  return NS_OK;
+}
+
+/**
+ * Note:  This object is only ever accessed on one thread at a time.  It it not
+ *        threadsafe, but it does need threadsafe AddRef and Release.
+ */
+NS_IMPL_ISUPPORTS(Row, mozIStorageRow, mozIStorageValueArray)
+
+////////////////////////////////////////////////////////////////////////////////
+//// mozIStorageRow
+
+NS_IMETHODIMP
+Row::GetResultByIndex(uint32_t aIndex, nsIVariant** _result) {
+  ENSURE_INDEX_VALUE(aIndex, mNumCols);
+  NS_ADDREF(*_result = mData.ObjectAt(aIndex));
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Row::GetResultByName(const nsACString& aName, nsIVariant** _result) {
+  uint32_t index;
+  NS_ENSURE_TRUE(mNameHashtable.Get(aName, &index), NS_ERROR_NOT_AVAILABLE);
+  return GetResultByIndex(index, _result);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// mozIStorageValueArray
+
+NS_IMETHODIMP
+Row::GetNumEntries(uint32_t* _entries) {
+  *_entries = mNumCols;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Row::GetTypeOfIndex(uint32_t aIndex, int32_t* _type) {
+  ENSURE_INDEX_VALUE(aIndex, mNumCols);
+
+  uint16_t type = mData.ObjectAt(aIndex)->GetDataType();
+  switch (type) {
+    case nsIDataType::VTYPE_INT32:
+    case nsIDataType::VTYPE_INT64:
+      *_type = mozIStorageValueArray::VALUE_TYPE_INTEGER;
+      break;
+    case nsIDataType::VTYPE_DOUBLE:
+      *_type = mozIStorageValueArray::VALUE_TYPE_FLOAT;
+      break;
+    case nsIDataType::VTYPE_ASTRING:
+      *_type = mozIStorageValueArray::VALUE_TYPE_TEXT;
+      break;
+    case nsIDataType::VTYPE_ARRAY:
+      *_type = mozIStorageValueArray::VALUE_TYPE_BLOB;
+      break;
+    default:
+      *_type = mozIStorageValueArray::VALUE_TYPE_NULL;
+      break;
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Row::GetInt32(uint32_t aIndex, int32_t* _value) {
+  ENSURE_INDEX_VALUE(aIndex, mNumCols);
+  return mData.ObjectAt(aIndex)->GetAsInt32(_value);
+}
+
+NS_IMETHODIMP
+Row::GetInt64(uint32_t aIndex, int64_t* _value) {
+  ENSURE_INDEX_VALUE(aIndex, mNumCols);
+  return mData.ObjectAt(aIndex)->GetAsInt64(_value);
+}
+
+NS_IMETHODIMP
+Row::GetDouble(uint32_t aIndex, double* _value) {
+  ENSURE_INDEX_VALUE(aIndex, mNumCols);
+  return mData.ObjectAt(aIndex)->GetAsDouble(_value);
+}
+
+NS_IMETHODIMP
+Row::GetUTF8String(uint32_t aIndex, nsACString& _value) {
+  ENSURE_INDEX_VALUE(aIndex, mNumCols);
+  return mData.ObjectAt(aIndex)->GetAsAUTF8String(_value);
+}
+
+NS_IMETHODIMP
+Row::GetString(uint32_t aIndex, nsAString& _value) {
+  ENSURE_INDEX_VALUE(aIndex, mNumCols);
+  return mData.ObjectAt(aIndex)->GetAsAString(_value);
+}
+
+NS_IMETHODIMP
+Row::GetBlob(uint32_t aIndex, uint32_t* _size, uint8_t** _blob) {
+  ENSURE_INDEX_VALUE(aIndex, mNumCols);
+
+  uint16_t type;
+  nsIID interfaceIID;
+  return mData.ObjectAt(aIndex)->GetAsArray(&type, &interfaceIID, _size,
+                                            reinterpret_cast<void**>(_blob));
+}
+
+NS_IMETHODIMP
+Row::GetBlobAsString(uint32_t aIndex, nsAString& aValue) {
+  return DoGetBlobAsString(this, aIndex, aValue);
+}
+
+NS_IMETHODIMP
+Row::GetBlobAsUTF8String(uint32_t aIndex, nsACString& aValue) {
+  return DoGetBlobAsString(this, aIndex, aValue);
+}
+
+NS_IMETHODIMP
+Row::GetIsNull(uint32_t aIndex, bool* _isNull) {
+  ENSURE_INDEX_VALUE(aIndex, mNumCols);
+  NS_ENSURE_ARG_POINTER(_isNull);
+
+  uint16_t type = mData.ObjectAt(aIndex)->GetDataType();
+  *_isNull = type == nsIDataType::VTYPE_EMPTY;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Row::GetSharedUTF8String(uint32_t, uint32_t*, char const**) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+Row::GetSharedString(uint32_t, uint32_t*, const char16_t**) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+Row::GetSharedBlob(uint32_t, uint32_t*, const uint8_t**) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+}  // namespace storage
+}  // namespace mozilla
diff --git a/storage/mozStorageRow.h b/storage/mozStorageRow.h
new file mode 100644
index 0000000000..b816781719
--- /dev/null
+++ b/storage/mozStorageRow.h
@@ -0,0 +1,59 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozStorageRow_h
+#define mozStorageRow_h
+
+#include "mozIStorageRow.h"
+#include "nsCOMArray.h"
+#include "nsTHashMap.h"
+#include "mozilla/Attributes.h"
+class nsIVariant;
+struct sqlite3_stmt;
+
+namespace mozilla {
+namespace storage {
+
+class Row final : public mozIStorageRow {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEROW
+  NS_DECL_MOZISTORAGEVALUEARRAY
+
+  Row() : mNumCols(0) {}
+
+  /**
+   * Initializes the object with the given statement.  Copies the values from
+   * the statement.
+   *
+   * @param aStatement
+   *        The sqlite statement to pull results from.
+   */
+  nsresult initialize(sqlite3_stmt* aStatement);
+
+ private:
+  ~Row() {}
+
+  /**
+   * The number of columns in this tuple.
+   */
+  uint32_t mNumCols;
+
+  /**
+   * Stores the data in the tuple.
+   */
+  nsCOMArray<nsIVariant> mData;
+
+  /**
+   * Maps a given name to a column index.
+   */
+  nsTHashMap<nsCStringHashKey, uint32_t> mNameHashtable;
+};
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif  // mozStorageRow_h
diff --git a/storage/mozStorageSQLFunctions.cpp b/storage/mozStorageSQLFunctions.cpp
new file mode 100644
index 0000000000..c05010c2ff
--- /dev/null
+++ b/storage/mozStorageSQLFunctions.cpp
@@ -0,0 +1,369 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/ArrayUtils.h"
+
+#include "mozStorageSQLFunctions.h"
+#include "nsTArray.h"
+#include "nsUnicharUtils.h"
+#include <algorithm>
+#include "sqlite3.h"
+
+namespace mozilla {
+namespace storage {
+
+////////////////////////////////////////////////////////////////////////////////
+//// Local Helper Functions
+
+namespace {
+
+/**
+ * Performs the LIKE comparison of a string against a pattern.  For more detail
+ * see http://www.sqlite.org/lang_expr.html#like.
+ *
+ * @param aPatternItr
+ *        An iterator at the start of the pattern to check for.
+ * @param aPatternEnd
+ *        An iterator at the end of the pattern to check for.
+ * @param aStringItr
+ *        An iterator at the start of the string to check for the pattern.
+ * @param aStringEnd
+ *        An iterator at the end of the string to check for the pattern.
+ * @param aEscapeChar
+ *        The character to use for escaping symbols in the pattern.
+ * @return 1 if the pattern is found, 0 otherwise.
+ */
+int likeCompare(nsAString::const_iterator aPatternItr,
+                nsAString::const_iterator aPatternEnd,
+                nsAString::const_iterator aStringItr,
+                nsAString::const_iterator aStringEnd, char16_t aEscapeChar) {
+  const char16_t MATCH_ALL('%');
+  const char16_t MATCH_ONE('_');
+
+  bool lastWasEscape = false;
+  while (aPatternItr != aPatternEnd) {
+    /**
+     * What we do in here is take a look at each character from the input
+     * pattern, and do something with it.  There are 4 possibilities:
+     * 1) character is an un-escaped match-all character
+     * 2) character is an un-escaped match-one character
+     * 3) character is an un-escaped escape character
+     * 4) character is not any of the above
+     */
+    if (!lastWasEscape && *aPatternItr == MATCH_ALL) {
+      // CASE 1
+      /**
+       * Now we need to skip any MATCH_ALL or MATCH_ONE characters that follow a
+       * MATCH_ALL character.  For each MATCH_ONE character, skip one character
+       * in the pattern string.
+       */
+      while (*aPatternItr == MATCH_ALL || *aPatternItr == MATCH_ONE) {
+        if (*aPatternItr == MATCH_ONE) {
+          // If we've hit the end of the string we are testing, no match
+          if (aStringItr == aStringEnd) return 0;
+          aStringItr++;
+        }
+        aPatternItr++;
+      }
+
+      // If we've hit the end of the pattern string, match
+      if (aPatternItr == aPatternEnd) return 1;
+
+      while (aStringItr != aStringEnd) {
+        if (likeCompare(aPatternItr, aPatternEnd, aStringItr, aStringEnd,
+                        aEscapeChar)) {
+          // we've hit a match, so indicate this
+          return 1;
+        }
+        aStringItr++;
+      }
+
+      // No match
+      return 0;
+    }
+    if (!lastWasEscape && *aPatternItr == MATCH_ONE) {
+      // CASE 2
+      if (aStringItr == aStringEnd) {
+        // If we've hit the end of the string we are testing, no match
+        return 0;
+      }
+      aStringItr++;
+      lastWasEscape = false;
+    } else if (!lastWasEscape && *aPatternItr == aEscapeChar) {
+      // CASE 3
+      lastWasEscape = true;
+    } else {
+      // CASE 4
+      if (::ToUpperCase(*aStringItr) != ::ToUpperCase(*aPatternItr)) {
+        // If we've hit a point where the strings don't match, there is no match
+        return 0;
+      }
+      aStringItr++;
+      lastWasEscape = false;
+    }
+
+    aPatternItr++;
+  }
+
+  return aStringItr == aStringEnd;
+}
+
+/**
+ * Compute the Levenshtein Edit Distance between two strings.
+ *
+ * @param aStringS
+ *        a string
+ * @param aStringT
+ *        another string
+ * @param _result
+ *        an outparam that will receive the edit distance between the arguments
+ * @return a Sqlite result code, e.g. SQLITE_OK, SQLITE_NOMEM, etc.
+ */
+int levenshteinDistance(const nsAString& aStringS, const nsAString& aStringT,
+                        int* _result) {
+  // Set the result to a non-sensical value in case we encounter an error.
+  *_result = -1;
+
+  const uint32_t sLen = aStringS.Length();
+  const uint32_t tLen = aStringT.Length();
+
+  if (sLen == 0) {
+    *_result = tLen;
+    return SQLITE_OK;
+  }
+  if (tLen == 0) {
+    *_result = sLen;
+    return SQLITE_OK;
+  }
+
+  // Notionally, Levenshtein Distance is computed in a matrix.  If we
+  // assume s = "span" and t = "spam", the matrix would look like this:
+  //    s -->
+  //  t          s   p   a   n
+  //  |      0   1   2   3   4
+  //  V  s   1   *   *   *   *
+  //     p   2   *   *   *   *
+  //     a   3   *   *   *   *
+  //     m   4   *   *   *   *
+  //
+  // Note that the row width is sLen + 1 and the column height is tLen + 1,
+  // where sLen is the length of the string "s" and tLen is the length of "t".
+  // The first row and the first column are initialized as shown, and
+  // the algorithm computes the remaining cells row-by-row, and
+  // left-to-right within each row.  The computation only requires that
+  // we be able to see the current row and the previous one.
+
+  // Allocate memory for two rows.
+  AutoTArray<int, nsAutoString::kStorageSize> row1;
+  AutoTArray<int, nsAutoString::kStorageSize> row2;
+
+  // Declare the raw pointers that will actually be used to access the memory.
+  int* prevRow = row1.AppendElements(sLen + 1);
+  int* currRow = row2.AppendElements(sLen + 1);
+
+  // Initialize the first row.
+  for (uint32_t i = 0; i <= sLen; i++) prevRow[i] = i;
+
+  const char16_t* s = aStringS.BeginReading();
+  const char16_t* t = aStringT.BeginReading();
+
+  // Compute the empty cells in the "matrix" row-by-row, starting with
+  // the second row.
+  for (uint32_t ti = 1; ti <= tLen; ti++) {
+    // Initialize the first cell in this row.
+    currRow[0] = ti;
+
+    // Get the character from "t" that corresponds to this row.
+    const char16_t tch = t[ti - 1];
+
+    // Compute the remaining cells in this row, left-to-right,
+    // starting at the second column (and first character of "s").
+    for (uint32_t si = 1; si <= sLen; si++) {
+      // Get the character from "s" that corresponds to this column,
+      // compare it to the t-character, and compute the "cost".
+      const char16_t sch = s[si - 1];
+      int cost = (sch == tch) ? 0 : 1;
+
+      // ............ We want to calculate the value of cell "d" from
+      // ...ab....... the previously calculated (or initialized) cells
+      // ...cd....... "a", "b", and "c", where d = min(a', b', c').
+      // ............
+      int aPrime = prevRow[si - 1] + cost;
+      int bPrime = prevRow[si] + 1;
+      int cPrime = currRow[si - 1] + 1;
+      currRow[si] = std::min(aPrime, std::min(bPrime, cPrime));
+    }
+
+    // Advance to the next row.  The current row becomes the previous
+    // row and we recycle the old previous row as the new current row.
+    // We don't need to re-initialize the new current row since we will
+    // rewrite all of its cells anyway.
+    int* oldPrevRow = prevRow;
+    prevRow = currRow;
+    currRow = oldPrevRow;
+  }
+
+  // The final result is the value of the last cell in the last row.
+  // Note that that's now in the "previous" row, since we just swapped them.
+  *_result = prevRow[sLen];
+  return SQLITE_OK;
+}
+
+// This struct is used only by registerFunctions below, but ISO C++98 forbids
+// instantiating a template dependent on a locally-defined type.  Boo-urns!
+struct Functions {
+  const char* zName;
+  int nArg;
+  int enc;
+  void* pContext;
+  void (*xFunc)(::sqlite3_context*, int, sqlite3_value**);
+};
+
+}  // namespace
+
+////////////////////////////////////////////////////////////////////////////////
+//// Exposed Functions
+
+int registerFunctions(sqlite3* aDB) {
+  Functions functions[] = {
+      {"lower", 1, SQLITE_UTF16, 0, caseFunction},
+      {"lower", 1, SQLITE_UTF8, 0, caseFunction},
+      {"upper", 1, SQLITE_UTF16, (void*)1, caseFunction},
+      {"upper", 1, SQLITE_UTF8, (void*)1, caseFunction},
+
+      {"like", 2, SQLITE_UTF16, 0, likeFunction},
+      {"like", 2, SQLITE_UTF8, 0, likeFunction},
+      {"like", 3, SQLITE_UTF16, 0, likeFunction},
+      {"like", 3, SQLITE_UTF8, 0, likeFunction},
+
+      {"levenshteinDistance", 2, SQLITE_UTF16, 0, levenshteinDistanceFunction},
+      {"levenshteinDistance", 2, SQLITE_UTF8, 0, levenshteinDistanceFunction},
+
+      {"utf16Length", 1, SQLITE_UTF16, 0, utf16LengthFunction},
+      {"utf16Length", 1, SQLITE_UTF8, 0, utf16LengthFunction},
+  };
+
+  int rv = SQLITE_OK;
+  for (size_t i = 0; SQLITE_OK == rv && i < ArrayLength(functions); ++i) {
+    struct Functions* p = &functions[i];
+    rv = ::sqlite3_create_function(aDB, p->zName, p->nArg, p->enc, p->pContext,
+                                   p->xFunc, nullptr, nullptr);
+  }
+
+  return rv;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// SQL Functions
+
+void caseFunction(sqlite3_context* aCtx, int aArgc, sqlite3_value** aArgv) {
+  NS_ASSERTION(1 == aArgc, "Invalid number of arguments!");
+
+  const char16_t* value =
+      static_cast<const char16_t*>(::sqlite3_value_text16(aArgv[0]));
+  nsAutoString data(value,
+                    ::sqlite3_value_bytes16(aArgv[0]) / sizeof(char16_t));
+  bool toUpper = ::sqlite3_user_data(aCtx) ? true : false;
+
+  if (toUpper)
+    ::ToUpperCase(data);
+  else
+    ::ToLowerCase(data);
+
+  // Set the result.
+  ::sqlite3_result_text16(aCtx, data.get(), data.Length() * sizeof(char16_t),
+                          SQLITE_TRANSIENT);
+}
+
+/**
+ * This implements the like() SQL function.  This is used by the LIKE operator.
+ * The SQL statement 'A LIKE B' is implemented as 'like(B, A)', and if there is
+ * an escape character, say E, it is implemented as 'like(B, A, E)'.
+ */
+void likeFunction(sqlite3_context* aCtx, int aArgc, sqlite3_value** aArgv) {
+  NS_ASSERTION(2 == aArgc || 3 == aArgc, "Invalid number of arguments!");
+
+  if (::sqlite3_value_bytes(aArgv[0]) >
+      ::sqlite3_limit(::sqlite3_context_db_handle(aCtx),
+                      SQLITE_LIMIT_LIKE_PATTERN_LENGTH, -1)) {
+    ::sqlite3_result_error(aCtx, "LIKE or GLOB pattern too complex",
+                           SQLITE_TOOBIG);
+    return;
+  }
+
+  if (!::sqlite3_value_text16(aArgv[0]) || !::sqlite3_value_text16(aArgv[1]))
+    return;
+
+  const char16_t* a =
+      static_cast<const char16_t*>(::sqlite3_value_text16(aArgv[1]));
+  int aLen = ::sqlite3_value_bytes16(aArgv[1]) / sizeof(char16_t);
+  nsDependentString A(a, aLen);
+
+  const char16_t* b =
+      static_cast<const char16_t*>(::sqlite3_value_text16(aArgv[0]));
+  int bLen = ::sqlite3_value_bytes16(aArgv[0]) / sizeof(char16_t);
+  nsDependentString B(b, bLen);
+  NS_ASSERTION(!B.IsEmpty(), "LIKE string must not be null!");
+
+  char16_t E = 0;
+  if (3 == aArgc)
+    E = static_cast<const char16_t*>(::sqlite3_value_text16(aArgv[2]))[0];
+
+  nsAString::const_iterator itrString, endString;
+  A.BeginReading(itrString);
+  A.EndReading(endString);
+  nsAString::const_iterator itrPattern, endPattern;
+  B.BeginReading(itrPattern);
+  B.EndReading(endPattern);
+  ::sqlite3_result_int(
+      aCtx, likeCompare(itrPattern, endPattern, itrString, endString, E));
+}
+
+void levenshteinDistanceFunction(sqlite3_context* aCtx, int aArgc,
+                                 sqlite3_value** aArgv) {
+  NS_ASSERTION(2 == aArgc, "Invalid number of arguments!");
+
+  // If either argument is a SQL NULL, then return SQL NULL.
+  if (::sqlite3_value_type(aArgv[0]) == SQLITE_NULL ||
+      ::sqlite3_value_type(aArgv[1]) == SQLITE_NULL) {
+    ::sqlite3_result_null(aCtx);
+    return;
+  }
+
+  const char16_t* a =
+      static_cast<const char16_t*>(::sqlite3_value_text16(aArgv[0]));
+  int aLen = ::sqlite3_value_bytes16(aArgv[0]) / sizeof(char16_t);
+
+  const char16_t* b =
+      static_cast<const char16_t*>(::sqlite3_value_text16(aArgv[1]));
+  int bLen = ::sqlite3_value_bytes16(aArgv[1]) / sizeof(char16_t);
+
+  // Compute the Levenshtein Distance, and return the result (or error).
+  int distance = -1;
+  const nsDependentString A(a, aLen);
+  const nsDependentString B(b, bLen);
+  int status = levenshteinDistance(A, B, &distance);
+  if (status == SQLITE_OK) {
+    ::sqlite3_result_int(aCtx, distance);
+  } else if (status == SQLITE_NOMEM) {
+    ::sqlite3_result_error_nomem(aCtx);
+  } else {
+    ::sqlite3_result_error(aCtx, "User function returned error code", -1);
+  }
+}
+
+void utf16LengthFunction(sqlite3_context* aCtx, int aArgc,
+                         sqlite3_value** aArgv) {
+  NS_ASSERTION(1 == aArgc, "Invalid number of arguments!");
+
+  int len = ::sqlite3_value_bytes16(aArgv[0]) / sizeof(char16_t);
+
+  // Set the result.
+  ::sqlite3_result_int(aCtx, len);
+}
+
+}  // namespace storage
+}  // namespace mozilla
diff --git a/storage/mozStorageSQLFunctions.h b/storage/mozStorageSQLFunctions.h
new file mode 100644
index 0000000000..2a3f1f3d7e
--- /dev/null
+++ b/storage/mozStorageSQLFunctions.h
@@ -0,0 +1,85 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozStorageSQLFunctions_h
+#define mozStorageSQLFunctions_h
+
+#include "sqlite3.h"
+#include "nscore.h"
+
+namespace mozilla {
+namespace storage {
+
+/**
+ * Registers the functions declared here with the specified database.
+ *
+ * @param aDB
+ *        The database we'll be registering the functions with.
+ * @return the SQLite status code indicating success or failure.
+ */
+int registerFunctions(sqlite3* aDB);
+
+////////////////////////////////////////////////////////////////////////////////
+//// Predefined Functions
+
+/**
+ * Overridden function to perform the SQL functions UPPER and LOWER.  These
+ * support unicode, which the default implementations do not do.
+ *
+ * @param aCtx
+ *        The sqlite_context that this function is being called on.
+ * @param aArgc
+ *        The number of arguments the function is being called with.
+ * @param aArgv
+ *        An array of the arguments the functions is being called with.
+ */
+void caseFunction(sqlite3_context* aCtx, int aArgc, sqlite3_value** aArgv);
+
+/**
+ * Overridden function to perform the SQL function LIKE.  This supports unicode,
+ * which the default implementation does not do.
+ *
+ * @param aCtx
+ *        The sqlite_context that this function is being called on.
+ * @param aArgc
+ *        The number of arguments the function is being called with.
+ * @param aArgv
+ *        An array of the arguments the functions is being called with.
+ */
+void likeFunction(sqlite3_context* aCtx, int aArgc, sqlite3_value** aArgv);
+
+/**
+ * An implementation of the Levenshtein Edit Distance algorithm for use in
+ * Sqlite queries.
+ *
+ * @param aCtx
+ *        The sqlite_context that this function is being called on.
+ * @param aArgc
+ *        The number of arguments the function is being called with.
+ * @param aArgv
+ *        An array of the arguments the functions is being called with.
+ */
+void levenshteinDistanceFunction(sqlite3_context* aCtx, int aArgc,
+                                 sqlite3_value** aArgv);
+
+/**
+ * An alternative string length function that uses XPCOM string classes for
+ * string length calculation.
+ *
+ * @param aCtx
+ *        The sqlite_context that this function is being called on.
+ * @param aArgc
+ *        The number of arguments the function is being called with.
+ * @param aArgv
+ *        An array of the arguments the functions is being called with.
+ */
+void utf16LengthFunction(sqlite3_context* aCtx, int aArgc,
+                         sqlite3_value** aArgv);
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif  // mozStorageSQLFunctions_h
diff --git a/storage/mozStorageService.cpp b/storage/mozStorageService.cpp
new file mode 100644
index 0000000000..78aebb5d8d
--- /dev/null
+++ b/storage/mozStorageService.cpp
@@ -0,0 +1,744 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "BaseVFS.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/DebugOnly.h"
+#include "mozilla/SpinEventLoopUntil.h"
+#include "nsIFile.h"
+#include "nsIFileURL.h"
+#include "mozStorageService.h"
+#include "mozStorageConnection.h"
+#include "nsComponentManagerUtils.h"
+#include "nsEmbedCID.h"
+#include "nsExceptionHandler.h"
+#include "nsThreadUtils.h"
+#include "mozStoragePrivateHelpers.h"
+#include "nsIObserverService.h"
+#include "nsIPropertyBag2.h"
+#include "ObfuscatingVFS.h"
+#include "QuotaVFS.h"
+#include "mozilla/Services.h"
+#include "mozilla/LateWriteChecks.h"
+#include "mozIStorageCompletionCallback.h"
+#include "mozIStoragePendingStatement.h"
+#include "mozilla/StaticPrefs_storage.h"
+#include "mozilla/intl/Collator.h"
+#include "mozilla/intl/LocaleService.h"
+
+#include "sqlite3.h"
+#include "mozilla/AutoSQLiteLifetime.h"
+
+#ifdef XP_WIN
+// "windows.h" was included and it can #define lots of things we care about...
+#  undef CompareString
+#endif
+
+using mozilla::intl::Collator;
+
+namespace mozilla::storage {
+
+////////////////////////////////////////////////////////////////////////////////
+//// Memory Reporting
+
+#ifdef MOZ_DMD
+mozilla::Atomic<size_t> gSqliteMemoryUsed;
+#endif
+
+static int64_t StorageSQLiteDistinguishedAmount() {
+  return ::sqlite3_memory_used();
+}
+
+/**
+ * Passes a single SQLite memory statistic to a memory reporter callback.
+ *
+ * @param aHandleReport
+ *        The callback.
+ * @param aData
+ *        The data for the callback.
+ * @param aConn
+ *        The SQLite connection.
+ * @param aPathHead
+ *        Head of the path for the memory report.
+ * @param aKind
+ *        The memory report statistic kind, one of "stmt", "cache" or
+ *        "schema".
+ * @param aDesc
+ *        The memory report description.
+ * @param aOption
+ *        The SQLite constant for getting the measurement.
+ * @param aTotal
+ *        The accumulator for the measurement.
+ */
+static void ReportConn(nsIHandleReportCallback* aHandleReport,
+                       nsISupports* aData, Connection* aConn,
+                       const nsACString& aPathHead, const nsACString& aKind,
+                       const nsACString& aDesc, int32_t aOption,
+                       size_t* aTotal) {
+  nsCString path(aPathHead);
+  path.Append(aKind);
+  path.AppendLiteral("-used");
+
+  int32_t val = aConn->getSqliteRuntimeStatus(aOption);
+  aHandleReport->Callback(""_ns, path, nsIMemoryReporter::KIND_HEAP,
+                          nsIMemoryReporter::UNITS_BYTES, int64_t(val), aDesc,
+                          aData);
+  *aTotal += val;
+}
+
+// Warning: To get a Connection's measurements requires holding its lock.
+// There may be a delay getting the lock if another thread is accessing the
+// Connection.  This isn't very nice if CollectReports is called from the main
+// thread!  But at the time of writing this function is only called when
+// about:memory is loaded (not, for example, when telemetry pings occur) and
+// any delays in that case aren't so bad.
+NS_IMETHODIMP
+Service::CollectReports(nsIHandleReportCallback* aHandleReport,
+                        nsISupports* aData, bool aAnonymize) {
+  size_t totalConnSize = 0;
+  {
+    nsTArray<RefPtr<Connection>> connections;
+    getConnections(connections);
+
+    for (uint32_t i = 0; i < connections.Length(); i++) {
+      RefPtr<Connection>& conn = connections[i];
+
+      // Someone may have closed the Connection, in which case we skip it.
+      // Note that we have consumers of the synchronous API that are off the
+      // main-thread, like the DOM Cache and IndexedDB, and as such we must be
+      // sure that we have a connection.
+      MutexAutoLock lockedAsyncScope(conn->sharedAsyncExecutionMutex);
+      if (!conn->connectionReady()) {
+        continue;
+      }
+
+      nsCString pathHead("explicit/storage/sqlite/");
+      // This filename isn't privacy-sensitive, and so is never anonymized.
+      pathHead.Append(conn->getFilename());
+      pathHead.Append('/');
+
+      SQLiteMutexAutoLock lockedScope(conn->sharedDBMutex);
+
+      constexpr auto stmtDesc =
+          "Memory (approximate) used by all prepared statements used by "
+          "connections to this database."_ns;
+      ReportConn(aHandleReport, aData, conn, pathHead, "stmt"_ns, stmtDesc,
+                 SQLITE_DBSTATUS_STMT_USED, &totalConnSize);
+
+      constexpr auto cacheDesc =
+          "Memory (approximate) used by all pager caches used by connections "
+          "to this database."_ns;
+      ReportConn(aHandleReport, aData, conn, pathHead, "cache"_ns, cacheDesc,
+                 SQLITE_DBSTATUS_CACHE_USED_SHARED, &totalConnSize);
+
+      constexpr auto schemaDesc =
+          "Memory (approximate) used to store the schema for all databases "
+          "associated with connections to this database."_ns;
+      ReportConn(aHandleReport, aData, conn, pathHead, "schema"_ns, schemaDesc,
+                 SQLITE_DBSTATUS_SCHEMA_USED, &totalConnSize);
+    }
+
+#ifdef MOZ_DMD
+    if (::sqlite3_memory_used() != int64_t(gSqliteMemoryUsed)) {
+      NS_WARNING(
+          "memory consumption reported by SQLite doesn't match "
+          "our measurements");
+    }
+#endif
+  }
+
+  int64_t other = static_cast<int64_t>(::sqlite3_memory_used() - totalConnSize);
+
+  MOZ_COLLECT_REPORT("explicit/storage/sqlite/other", KIND_HEAP, UNITS_BYTES,
+                     other, "All unclassified sqlite memory.");
+
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Service
+
+NS_IMPL_ISUPPORTS(Service, mozIStorageService, nsIObserver, nsIMemoryReporter)
+
+Service* Service::gService = nullptr;
+
+already_AddRefed<Service> Service::getSingleton() {
+  if (gService) {
+    return do_AddRef(gService);
+  }
+
+  // The first reference to the storage service must be obtained on the
+  // main thread.
+  NS_ENSURE_TRUE(NS_IsMainThread(), nullptr);
+  RefPtr<Service> service = new Service();
+  if (NS_SUCCEEDED(service->initialize())) {
+    // Note: This is cleared in the Service destructor.
+    gService = service.get();
+    return service.forget();
+  }
+
+  return nullptr;
+}
+
+int Service::AutoVFSRegistration::Init(UniquePtr<sqlite3_vfs> aVFS) {
+  MOZ_ASSERT(!mVFS);
+  if (aVFS) {
+    mVFS = std::move(aVFS);
+    return sqlite3_vfs_register(mVFS.get(), 0);
+  }
+  NS_WARNING("Failed to register VFS");
+  return SQLITE_OK;
+}
+
+Service::AutoVFSRegistration::~AutoVFSRegistration() {
+  if (mVFS) {
+    int rc = sqlite3_vfs_unregister(mVFS.get());
+    if (rc != SQLITE_OK) {
+      NS_WARNING("Failed to unregister sqlite vfs wrapper.");
+    }
+  }
+}
+
+Service::Service()
+    : mMutex("Service::mMutex"),
+      mRegistrationMutex("Service::mRegistrationMutex"),
+      mLastSensitivity(mozilla::intl::Collator::Sensitivity::Base) {}
+
+Service::~Service() {
+  mozilla::UnregisterWeakMemoryReporter(this);
+  mozilla::UnregisterStorageSQLiteDistinguishedAmount();
+
+  gService = nullptr;
+}
+
+void Service::registerConnection(Connection* aConnection) {
+  mRegistrationMutex.AssertNotCurrentThreadOwns();
+  MutexAutoLock mutex(mRegistrationMutex);
+  (void)mConnections.AppendElement(aConnection);
+}
+
+void Service::unregisterConnection(Connection* aConnection) {
+  // If this is the last Connection it might be the only thing keeping Service
+  // alive.  So ensure that Service is destroyed only after the Connection is
+  // cleanly unregistered and destroyed.
+  RefPtr<Service> kungFuDeathGrip(this);
+  RefPtr<Connection> forgettingRef;
+  {
+    mRegistrationMutex.AssertNotCurrentThreadOwns();
+    MutexAutoLock mutex(mRegistrationMutex);
+
+    for (uint32_t i = 0; i < mConnections.Length(); ++i) {
+      if (mConnections[i] == aConnection) {
+        // Because dropping the final reference can potentially result in
+        // spinning a nested event loop if the connection was not properly
+        // shutdown, we want to do that outside this loop so that we can finish
+        // mutating the array and drop our mutex.
+        forgettingRef = std::move(mConnections[i]);
+        mConnections.RemoveElementAt(i);
+        break;
+      }
+    }
+  }
+
+  MOZ_ASSERT(forgettingRef,
+             "Attempt to unregister unknown storage connection!");
+
+  // Do not proxy the release anywhere, just let this reference drop here. (We
+  // previously did proxy the release, but that was because we invoked Close()
+  // in the destructor and Close() likes to complain if it's not invoked on the
+  // opener event target, so it was essential that the last reference be dropped
+  // on the opener event target.  We now enqueue Close() inside our caller,
+  // Release(), so it doesn't actually matter what thread our reference drops
+  // on.)
+}
+
+void Service::getConnections(
+    /* inout */ nsTArray<RefPtr<Connection>>& aConnections) {
+  mRegistrationMutex.AssertNotCurrentThreadOwns();
+  MutexAutoLock mutex(mRegistrationMutex);
+  aConnections.Clear();
+  aConnections.AppendElements(mConnections);
+}
+
+void Service::minimizeMemory() {
+  nsTArray<RefPtr<Connection>> connections;
+  getConnections(connections);
+
+  for (uint32_t i = 0; i < connections.Length(); i++) {
+    RefPtr<Connection> conn = connections[i];
+    // For non-main-thread owning/opening threads, we may be racing against them
+    // closing their connection or their thread.  That's okay, see below.
+    if (!conn->connectionReady()) {
+      continue;
+    }
+
+    constexpr auto shrinkPragma = "PRAGMA shrink_memory"_ns;
+
+    if (!conn->operationSupported(Connection::SYNCHRONOUS)) {
+      // This is a mozIStorageAsyncConnection, it can only be used on the main
+      // thread, so we can do a straight API call.
+      nsCOMPtr<mozIStoragePendingStatement> ps;
+      DebugOnly<nsresult> rv = conn->ExecuteSimpleSQLAsync(
+          shrinkPragma, nullptr, getter_AddRefs(ps));
+      MOZ_ASSERT(NS_SUCCEEDED(rv), "Should have purged sqlite caches");
+    } else if (IsOnCurrentSerialEventTarget(conn->eventTargetOpenedOn)) {
+      if (conn->isAsyncExecutionThreadAvailable()) {
+        nsCOMPtr<mozIStoragePendingStatement> ps;
+        DebugOnly<nsresult> rv = conn->ExecuteSimpleSQLAsync(
+            shrinkPragma, nullptr, getter_AddRefs(ps));
+        MOZ_ASSERT(NS_SUCCEEDED(rv), "Should have purged sqlite caches");
+      } else {
+        conn->ExecuteSimpleSQL(shrinkPragma);
+      }
+    } else {
+      // We are on the wrong event target, the query should be executed on the
+      // opener event target, so we must dispatch to it.
+      // It's possible the connection is already closed or will be closed by the
+      // time our runnable runs. ExecuteSimpleSQL will safely return with a
+      // failure in that case. If the event target is shutting down or shut
+      // down, the dispatch will fail and that's okay.
+      nsCOMPtr<nsIRunnable> event = NewRunnableMethod<const nsCString>(
+          "Connection::ExecuteSimpleSQL", conn, &Connection::ExecuteSimpleSQL,
+          shrinkPragma);
+      Unused << conn->eventTargetOpenedOn->Dispatch(event, NS_DISPATCH_NORMAL);
+    }
+  }
+}
+
+UniquePtr<sqlite3_vfs> ConstructReadOnlyNoLockVFS();
+
+static const char* sObserverTopics[] = {"memory-pressure",
+                                        "xpcom-shutdown-threads"};
+
+nsresult Service::initialize() {
+  MOZ_ASSERT(NS_IsMainThread(), "Must be initialized on the main thread");
+
+  int rc = AutoSQLiteLifetime::getInitResult();
+  if (rc != SQLITE_OK) {
+    return convertResultCode(rc);
+  }
+
+  /**
+   *                    The virtual file system hierarchy
+   *
+   *                                 obfsvfs
+   *                                    |
+   *                                    |
+   *                                    |
+   *                                 quotavfs
+   *                                   / \
+   *                                 /     \
+   *                               /         \
+   *                             /             \
+   *                           /                 \
+   *                     base-vfs-excl        base-vfs
+   *                          / \               / \
+   *                        /     \           /     \
+   *                      /         \       /         \
+   *                 unix-excl     win32  unix       win32
+   */
+
+  rc = mBaseSqliteVFS.Init(basevfs::ConstructVFS(false));
+  if (rc != SQLITE_OK) {
+    return convertResultCode(rc);
+  }
+
+  rc = mBaseExclSqliteVFS.Init(basevfs::ConstructVFS(true));
+  if (rc != SQLITE_OK) {
+    return convertResultCode(rc);
+  }
+
+  rc = mQuotaSqliteVFS.Init(quotavfs::ConstructVFS(basevfs::GetVFSName(
+      StaticPrefs::storage_sqlite_exclusiveLock_enabled())));
+  if (rc != SQLITE_OK) {
+    return convertResultCode(rc);
+  }
+
+  rc =
+      mObfuscatingSqliteVFS.Init(obfsvfs::ConstructVFS(quotavfs::GetVFSName()));
+  if (rc != SQLITE_OK) {
+    return convertResultCode(rc);
+  }
+
+  rc = mReadOnlyNoLockSqliteVFS.Init(ConstructReadOnlyNoLockVFS());
+  if (rc != SQLITE_OK) {
+    return convertResultCode(rc);
+  }
+
+  nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+  NS_ENSURE_TRUE(os, NS_ERROR_FAILURE);
+
+  for (auto& sObserverTopic : sObserverTopics) {
+    nsresult rv = os->AddObserver(this, sObserverTopic, false);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+  }
+
+  mozilla::RegisterWeakMemoryReporter(this);
+  mozilla::RegisterStorageSQLiteDistinguishedAmount(
+      StorageSQLiteDistinguishedAmount);
+
+  return NS_OK;
+}
+
+int Service::localeCompareStrings(const nsAString& aStr1,
+                                  const nsAString& aStr2,
+                                  Collator::Sensitivity aSensitivity) {
+  // The mozilla::intl::Collator is not thread safe, since the Collator::Options
+  // can be changed.
+  MutexAutoLock mutex(mMutex);
+
+  Collator* collator = getCollator();
+  if (!collator) {
+    NS_ERROR("Storage service has no collation");
+    return 0;
+  }
+
+  if (aSensitivity != mLastSensitivity) {
+    Collator::Options options{};
+    options.sensitivity = aSensitivity;
+    auto result = mCollator->SetOptions(options);
+
+    if (result.isErr()) {
+      NS_WARNING("Could not configure the mozilla::intl::Collation.");
+      return 0;
+    }
+    mLastSensitivity = aSensitivity;
+  }
+
+  return collator->CompareStrings(aStr1, aStr2);
+}
+
+Collator* Service::getCollator() {
+  mMutex.AssertCurrentThreadOwns();
+
+  if (mCollator) {
+    return mCollator.get();
+  }
+
+  auto result = mozilla::intl::LocaleService::TryCreateComponent<Collator>();
+  if (result.isErr()) {
+    NS_WARNING("Could not create mozilla::intl::Collation.");
+    return nullptr;
+  }
+
+  mCollator = result.unwrap();
+
+  // Sort in a case-insensitive way, where "base" letters are considered
+  // equal, e.g: a = á, a = A, a ≠ b.
+  Collator::Options options{};
+  options.sensitivity = Collator::Sensitivity::Base;
+  auto optResult = mCollator->SetOptions(options);
+
+  if (optResult.isErr()) {
+    NS_WARNING("Could not configure the mozilla::intl::Collation.");
+    mCollator = nullptr;
+    return nullptr;
+  }
+
+  return mCollator.get();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// mozIStorageService
+
+NS_IMETHODIMP
+Service::OpenSpecialDatabase(const nsACString& aStorageKey,
+                             const nsACString& aName, uint32_t aConnectionFlags,
+                             mozIStorageConnection** _connection) {
+  if (!aStorageKey.Equals(kMozStorageMemoryStorageKey)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  const bool interruptible =
+      aConnectionFlags & mozIStorageService::CONNECTION_INTERRUPTIBLE;
+
+  int flags = SQLITE_OPEN_READWRITE;
+
+  if (!aName.IsEmpty()) {
+    flags |= SQLITE_OPEN_URI;
+  }
+
+  RefPtr<Connection> msc =
+      new Connection(this, flags, Connection::SYNCHRONOUS,
+                     kMozStorageMemoryStorageKey, interruptible);
+  const nsresult rv = msc->initialize(aStorageKey, aName);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  msc.forget(_connection);
+  return NS_OK;
+}
+
+namespace {
+
+class AsyncInitDatabase final : public Runnable {
+ public:
+  AsyncInitDatabase(Connection* aConnection, nsIFile* aStorageFile,
+                    int32_t aGrowthIncrement,
+                    mozIStorageCompletionCallback* aCallback)
+      : Runnable("storage::AsyncInitDatabase"),
+        mConnection(aConnection),
+        mStorageFile(aStorageFile),
+        mGrowthIncrement(aGrowthIncrement),
+        mCallback(aCallback) {
+    MOZ_ASSERT(NS_IsMainThread());
+  }
+
+  NS_IMETHOD Run() override {
+    MOZ_ASSERT(!NS_IsMainThread());
+    nsresult rv = mConnection->initializeOnAsyncThread(mStorageFile);
+    if (NS_FAILED(rv)) {
+      return DispatchResult(rv, nullptr);
+    }
+
+    if (mGrowthIncrement >= 0) {
+      // Ignore errors. In the future, we might wish to log them.
+      (void)mConnection->SetGrowthIncrement(mGrowthIncrement, ""_ns);
+    }
+
+    return DispatchResult(
+        NS_OK, NS_ISUPPORTS_CAST(mozIStorageAsyncConnection*, mConnection));
+  }
+
+ private:
+  nsresult DispatchResult(nsresult aStatus, nsISupports* aValue) {
+    RefPtr<CallbackComplete> event =
+        new CallbackComplete(aStatus, aValue, mCallback.forget());
+    return NS_DispatchToMainThread(event);
+  }
+
+  ~AsyncInitDatabase() {
+    NS_ReleaseOnMainThread("AsyncInitDatabase::mStorageFile",
+                           mStorageFile.forget());
+    NS_ReleaseOnMainThread("AsyncInitDatabase::mConnection",
+                           mConnection.forget());
+
+    // Generally, the callback will be released by CallbackComplete.
+    // However, if for some reason Run() is not executed, we still
+    // need to ensure that it is released here.
+    NS_ReleaseOnMainThread("AsyncInitDatabase::mCallback", mCallback.forget());
+  }
+
+  RefPtr<Connection> mConnection;
+  nsCOMPtr<nsIFile> mStorageFile;
+  int32_t mGrowthIncrement;
+  RefPtr<mozIStorageCompletionCallback> mCallback;
+};
+
+}  // namespace
+
+NS_IMETHODIMP
+Service::OpenAsyncDatabase(nsIVariant* aDatabaseStore, uint32_t aOpenFlags,
+                           uint32_t /* aConnectionFlags */,
+                           mozIStorageCompletionCallback* aCallback) {
+  if (!NS_IsMainThread()) {
+    return NS_ERROR_NOT_SAME_THREAD;
+  }
+  NS_ENSURE_ARG(aDatabaseStore);
+  NS_ENSURE_ARG(aCallback);
+
+  const bool shared = aOpenFlags & mozIStorageService::OPEN_SHARED;
+  const bool ignoreLockingMode =
+      aOpenFlags & mozIStorageService::OPEN_IGNORE_LOCKING_MODE;
+  // Specifying ignoreLockingMode will force use of the readOnly flag:
+  const bool readOnly =
+      ignoreLockingMode || (aOpenFlags & mozIStorageService::OPEN_READONLY);
+  int flags = readOnly ? SQLITE_OPEN_READONLY : SQLITE_OPEN_READWRITE;
+
+  nsCOMPtr<nsIFile> storageFile;
+  nsCOMPtr<nsISupports> dbStore;
+  nsresult rv = aDatabaseStore->GetAsISupports(getter_AddRefs(dbStore));
+  if (NS_SUCCEEDED(rv)) {
+    // Generally, aDatabaseStore holds the database nsIFile.
+    storageFile = do_QueryInterface(dbStore, &rv);
+    if (NS_FAILED(rv)) {
+      return NS_ERROR_INVALID_ARG;
+    }
+
+    nsCOMPtr<nsIFile> cloned;
+    rv = storageFile->Clone(getter_AddRefs(cloned));
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    storageFile = std::move(cloned);
+
+    if (!readOnly) {
+      // Ensure that SQLITE_OPEN_CREATE is passed in for compatibility reasons.
+      flags |= SQLITE_OPEN_CREATE;
+    }
+
+    // Apply the shared-cache option.
+    flags |= shared ? SQLITE_OPEN_SHAREDCACHE : SQLITE_OPEN_PRIVATECACHE;
+  } else {
+    // Sometimes, however, it's a special database name.
+    nsAutoCString keyString;
+    rv = aDatabaseStore->GetAsACString(keyString);
+    if (NS_FAILED(rv) || !keyString.Equals(kMozStorageMemoryStorageKey)) {
+      return NS_ERROR_INVALID_ARG;
+    }
+
+    // Just fall through with nullptr storageFile, this will cause the storage
+    // connection to use a memory DB.
+  }
+
+  // Create connection on this thread, but initialize it on its helper thread.
+  nsAutoCString telemetryFilename;
+  if (!storageFile) {
+    telemetryFilename.Assign(kMozStorageMemoryStorageKey);
+  } else {
+    rv = storageFile->GetNativeLeafName(telemetryFilename);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  RefPtr<Connection> msc =
+      new Connection(this, flags, Connection::ASYNCHRONOUS, telemetryFilename,
+                     /* interruptible */ true, ignoreLockingMode);
+  nsCOMPtr<nsIEventTarget> target = msc->getAsyncExecutionTarget();
+  MOZ_ASSERT(target,
+             "Cannot initialize a connection that has been closed already");
+
+  RefPtr<AsyncInitDatabase> asyncInit = new AsyncInitDatabase(
+      msc, storageFile, /* growthIncrement */ -1, aCallback);
+  return target->Dispatch(asyncInit, nsIEventTarget::DISPATCH_NORMAL);
+}
+
+NS_IMETHODIMP
+Service::OpenDatabase(nsIFile* aDatabaseFile, uint32_t aConnectionFlags,
+                      mozIStorageConnection** _connection) {
+  NS_ENSURE_ARG(aDatabaseFile);
+
+  const bool interruptible =
+      aConnectionFlags & mozIStorageService::CONNECTION_INTERRUPTIBLE;
+
+  // Always ensure that SQLITE_OPEN_CREATE is passed in for compatibility
+  // reasons.
+  const int flags =
+      SQLITE_OPEN_READWRITE | SQLITE_OPEN_SHAREDCACHE | SQLITE_OPEN_CREATE;
+  nsAutoCString telemetryFilename;
+  nsresult rv = aDatabaseFile->GetNativeLeafName(telemetryFilename);
+  NS_ENSURE_SUCCESS(rv, rv);
+  RefPtr<Connection> msc = new Connection(this, flags, Connection::SYNCHRONOUS,
+                                          telemetryFilename, interruptible);
+  rv = msc->initialize(aDatabaseFile);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  msc.forget(_connection);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Service::OpenUnsharedDatabase(nsIFile* aDatabaseFile, uint32_t aConnectionFlags,
+                              mozIStorageConnection** _connection) {
+  NS_ENSURE_ARG(aDatabaseFile);
+
+  const bool interruptible =
+      aConnectionFlags & mozIStorageService::CONNECTION_INTERRUPTIBLE;
+
+  // Always ensure that SQLITE_OPEN_CREATE is passed in for compatibility
+  // reasons.
+  const int flags =
+      SQLITE_OPEN_READWRITE | SQLITE_OPEN_PRIVATECACHE | SQLITE_OPEN_CREATE;
+  nsAutoCString telemetryFilename;
+  nsresult rv = aDatabaseFile->GetNativeLeafName(telemetryFilename);
+  NS_ENSURE_SUCCESS(rv, rv);
+  RefPtr<Connection> msc = new Connection(this, flags, Connection::SYNCHRONOUS,
+                                          telemetryFilename, interruptible);
+  rv = msc->initialize(aDatabaseFile);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  msc.forget(_connection);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Service::OpenDatabaseWithFileURL(nsIFileURL* aFileURL,
+                                 const nsACString& aTelemetryFilename,
+                                 uint32_t aConnectionFlags,
+                                 mozIStorageConnection** _connection) {
+  NS_ENSURE_ARG(aFileURL);
+
+  const bool interruptible =
+      aConnectionFlags & mozIStorageService::CONNECTION_INTERRUPTIBLE;
+
+  // Always ensure that SQLITE_OPEN_CREATE is passed in for compatibility
+  // reasons.
+  const int flags = SQLITE_OPEN_READWRITE | SQLITE_OPEN_SHAREDCACHE |
+                    SQLITE_OPEN_CREATE | SQLITE_OPEN_URI;
+  nsresult rv;
+  nsAutoCString telemetryFilename;
+  if (!aTelemetryFilename.IsEmpty()) {
+    telemetryFilename = aTelemetryFilename;
+  } else {
+    nsCOMPtr<nsIFile> databaseFile;
+    rv = aFileURL->GetFile(getter_AddRefs(databaseFile));
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = databaseFile->GetNativeLeafName(telemetryFilename);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  RefPtr<Connection> msc = new Connection(this, flags, Connection::SYNCHRONOUS,
+                                          telemetryFilename, interruptible);
+  rv = msc->initialize(aFileURL);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  msc.forget(_connection);
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsIObserver
+
+NS_IMETHODIMP
+Service::Observe(nsISupports*, const char* aTopic, const char16_t*) {
+  if (strcmp(aTopic, "memory-pressure") == 0) {
+    minimizeMemory();
+  } else if (strcmp(aTopic, "xpcom-shutdown-threads") == 0) {
+    // The Service is kept alive by our strong observer references and
+    // references held by Connection instances.  Since we're about to remove the
+    // former and then wait for the latter ones to go away, it behooves us to
+    // hold a strong reference to ourselves so our calls to getConnections() do
+    // not happen on a deleted object.
+    RefPtr<Service> kungFuDeathGrip = this;
+
+    nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+
+    for (auto& sObserverTopic : sObserverTopics) {
+      (void)os->RemoveObserver(this, sObserverTopic);
+    }
+
+    SpinEventLoopUntil("storage::Service::Observe(xpcom-shutdown-threads)"_ns,
+                       [&]() -> bool {
+                         // We must wait until all the closing connections are
+                         // closed.
+                         nsTArray<RefPtr<Connection>> connections;
+                         getConnections(connections);
+                         for (auto& conn : connections) {
+                           if (conn->isClosing()) {
+                             return false;
+                           }
+                         }
+                         return true;
+                       });
+
+#ifdef DEBUG
+    nsTArray<RefPtr<Connection>> connections;
+    getConnections(connections);
+    for (uint32_t i = 0, n = connections.Length(); i < n; i++) {
+      if (!connections[i]->isClosed()) {
+        // getFilename is only the leaf name for the database file,
+        // so it shouldn't contain privacy-sensitive information.
+        CrashReporter::AnnotateCrashReport(
+            CrashReporter::Annotation::StorageConnectionNotClosed,
+            connections[i]->getFilename());
+        printf_stderr("Storage connection not closed: %s",
+                      connections[i]->getFilename().get());
+        MOZ_CRASH();
+      }
+    }
+#endif
+  }
+
+  return NS_OK;
+}
+
+}  // namespace mozilla::storage
diff --git a/storage/mozStorageService.h b/storage/mozStorageService.h
new file mode 100644
index 0000000000..fc8686f122
--- /dev/null
+++ b/storage/mozStorageService.h
@@ -0,0 +1,183 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef MOZSTORAGESERVICE_H
+#define MOZSTORAGESERVICE_H
+
+#include "nsCOMPtr.h"
+#include "nsIFile.h"
+#include "nsIMemoryReporter.h"
+#include "nsIObserver.h"
+#include "nsTArray.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/intl/Collator.h"
+
+#include "mozIStorageService.h"
+
+class nsIMemoryReporter;
+struct sqlite3_vfs;
+namespace mozilla::intl {
+class Collator;
+}
+
+namespace mozilla::storage {
+
+class Connection;
+class Service : public mozIStorageService,
+                public nsIObserver,
+                public nsIMemoryReporter {
+ public:
+  /**
+   * Initializes the service.  This must be called before any other function!
+   */
+  nsresult initialize();
+
+  /**
+   * Compares two strings using the Service's locale-aware collation.
+   *
+   * @param  aStr1
+   *         The string to be compared against aStr2.
+   * @param  aStr2
+   *         The string to be compared against aStr1.
+   * @param  aSensitivity
+   *         The sorting sensitivity.
+   * @return aStr1 - aStr2.  That is, if aStr1 < aStr2, returns a negative
+   *         number.  If aStr1 > aStr2, returns a positive number.  If
+   *         aStr1 == aStr2, returns 0.
+   */
+  int localeCompareStrings(const nsAString& aStr1, const nsAString& aStr2,
+                           mozilla::intl::Collator::Sensitivity aSensitivity);
+
+  static already_AddRefed<Service> getSingleton();
+
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGESERVICE
+  NS_DECL_NSIOBSERVER
+  NS_DECL_NSIMEMORYREPORTER
+
+  /**
+   * Returns a boolean value indicating whether or not the given page size is
+   * valid (currently understood as a power of 2 between 512 and 65536).
+   */
+  static bool pageSizeIsValid(int32_t aPageSize) {
+    return aPageSize == 512 || aPageSize == 1024 || aPageSize == 2048 ||
+           aPageSize == 4096 || aPageSize == 8192 || aPageSize == 16384 ||
+           aPageSize == 32768 || aPageSize == 65536;
+  }
+
+  static const int32_t kDefaultPageSize = 32768;
+
+  /**
+   * Registers the connection with the storage service.  Connections are
+   * registered so they can be iterated over.
+   *
+   * @pre mRegistrationMutex is not held
+   *
+   * @param  aConnection
+   *         The connection to register.
+   */
+  void registerConnection(Connection* aConnection);
+
+  /**
+   * Unregisters the connection with the storage service.
+   *
+   * @pre mRegistrationMutex is not held
+   *
+   * @param  aConnection
+   *         The connection to unregister.
+   */
+  void unregisterConnection(Connection* aConnection);
+
+  /**
+   * Gets the list of open connections.  Note that you must test each
+   * connection with mozIStorageConnection::connectionReady before doing
+   * anything with it, and skip it if it's not ready.
+   *
+   * @pre mRegistrationMutex is not held
+   *
+   * @param  aConnections
+   *         An inout param;  it is cleared and the connections are appended to
+   *         it.
+   * @return The open connections.
+   */
+  void getConnections(nsTArray<RefPtr<Connection> >& aConnections);
+
+ private:
+  Service();
+  virtual ~Service();
+
+  /**
+   * Used for 1) locking around calls when initializing connections so that we
+   * can ensure that the state of sqlite3_enable_shared_cache is sane and 2)
+   * synchronizing access to mLocaleCollation.
+   */
+  Mutex mMutex MOZ_UNANNOTATED;
+
+  struct AutoVFSRegistration {
+    int Init(UniquePtr<sqlite3_vfs> aVFS);
+    ~AutoVFSRegistration();
+
+   private:
+    UniquePtr<sqlite3_vfs> mVFS;
+  };
+
+  // The order of these members should match the order of Init calls in
+  // initialize(), to ensure that the unregistration takes place in the reverse
+  // order.
+  AutoVFSRegistration mBaseSqliteVFS;
+  AutoVFSRegistration mBaseExclSqliteVFS;
+  AutoVFSRegistration mQuotaSqliteVFS;
+  AutoVFSRegistration mObfuscatingSqliteVFS;
+  AutoVFSRegistration mReadOnlyNoLockSqliteVFS;
+
+  /**
+   * Protects mConnections.
+   */
+  Mutex mRegistrationMutex MOZ_UNANNOTATED;
+
+  /**
+   * The list of connections we have created.  Modifications to it are
+   * protected by |mRegistrationMutex|.
+   */
+  nsTArray<RefPtr<Connection> > mConnections;
+
+  /**
+   * Frees as much heap memory as possible from all of the known open
+   * connections.
+   */
+  void minimizeMemory();
+
+  /**
+   * Lazily creates and returns a collator created from the application's
+   * locale that all statements of all Connections of this Service may use.
+   * Since the collator's lifetime is that of the Service and no statement may
+   * execute outside the lifetime of the Service, this method returns a raw
+   * pointer.
+   */
+  mozilla::intl::Collator* getCollator();
+
+  /**
+   * Lazily created collator that all statements of all Connections of this
+   * Service may use.  The collator is created from the application's locale.
+   *
+   * @note The collator is not thread-safe since the options can be changed
+   * between calls. Access should be synchronized.
+   */
+  mozilla::UniquePtr<mozilla::intl::Collator> mCollator = nullptr;
+
+  nsCOMPtr<nsIFile> mProfileStorageFile;
+
+  nsCOMPtr<nsIMemoryReporter> mStorageSQLiteReporter;
+
+  static Service* gService;
+
+  mozilla::intl::Collator::Sensitivity mLastSensitivity;
+};
+
+}  // namespace mozilla::storage
+
+#endif /* MOZSTORAGESERVICE_H */
diff --git a/storage/mozStorageStatement.cpp b/storage/mozStorageStatement.cpp
new file mode 100644
index 0000000000..6de46e6ea8
--- /dev/null
+++ b/storage/mozStorageStatement.cpp
@@ -0,0 +1,843 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <limits.h>
+#include <stdio.h>
+
+#include "nsError.h"
+#include "nsThreadUtils.h"
+#include "nsIClassInfoImpl.h"
+#include "Variant.h"
+
+#include "mozIStorageError.h"
+
+#include "mozStorageBindingParams.h"
+#include "mozStorageConnection.h"
+#include "mozStorageStatementJSHelper.h"
+#include "mozStoragePrivateHelpers.h"
+#include "mozStorageStatementParams.h"
+#include "mozStorageStatementRow.h"
+#include "mozStorageStatement.h"
+
+#include "mozilla/Logging.h"
+#include "mozilla/Printf.h"
+#include "mozilla/ProfilerLabels.h"
+
+extern mozilla::LazyLogModule gStorageLog;
+
+namespace mozilla {
+namespace storage {
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsIClassInfo
+
+NS_IMPL_CI_INTERFACE_GETTER(Statement, mozIStorageStatement,
+                            mozIStorageBaseStatement, mozIStorageBindingParams,
+                            mozIStorageValueArray,
+                            mozilla::storage::StorageBaseStatementInternal)
+
+class StatementClassInfo : public nsIClassInfo {
+ public:
+  constexpr StatementClassInfo() = default;
+
+  NS_DECL_ISUPPORTS_INHERITED
+
+  NS_IMETHOD
+  GetInterfaces(nsTArray<nsIID>& _array) override {
+    return NS_CI_INTERFACE_GETTER_NAME(Statement)(_array);
+  }
+
+  NS_IMETHOD
+  GetScriptableHelper(nsIXPCScriptable** _helper) override {
+    static StatementJSHelper sJSHelper;
+    *_helper = &sJSHelper;
+    return NS_OK;
+  }
+
+  NS_IMETHOD
+  GetContractID(nsACString& aContractID) override {
+    aContractID.SetIsVoid(true);
+    return NS_OK;
+  }
+
+  NS_IMETHOD
+  GetClassDescription(nsACString& aDesc) override {
+    aDesc.SetIsVoid(true);
+    return NS_OK;
+  }
+
+  NS_IMETHOD
+  GetClassID(nsCID** _id) override {
+    *_id = nullptr;
+    return NS_OK;
+  }
+
+  NS_IMETHOD
+  GetFlags(uint32_t* _flags) override {
+    *_flags = 0;
+    return NS_OK;
+  }
+
+  NS_IMETHOD
+  GetClassIDNoAlloc(nsCID* _cid) override { return NS_ERROR_NOT_AVAILABLE; }
+};
+
+NS_IMETHODIMP_(MozExternalRefCountType) StatementClassInfo::AddRef() {
+  return 2;
+}
+NS_IMETHODIMP_(MozExternalRefCountType) StatementClassInfo::Release() {
+  return 1;
+}
+NS_IMPL_QUERY_INTERFACE(StatementClassInfo, nsIClassInfo)
+
+static StatementClassInfo sStatementClassInfo;
+
+////////////////////////////////////////////////////////////////////////////////
+//// Statement
+
+Statement::Statement()
+    : mDBStatement(nullptr),
+      mParamCount(0),
+      mResultColumnCount(0),
+      mExecuting(false),
+      mQueryStatusRecorded(false),
+      mHasExecuted(false) {}
+
+nsresult Statement::initialize(Connection* aDBConnection,
+                               sqlite3* aNativeConnection,
+                               const nsACString& aSQLStatement) {
+  MOZ_ASSERT(aDBConnection, "No database connection given!");
+  MOZ_ASSERT(aDBConnection->isConnectionReadyOnThisThread(),
+             "Database connection should be valid");
+  MOZ_ASSERT(!mDBStatement, "Statement already initialized!");
+  MOZ_ASSERT(aNativeConnection, "No native connection given!");
+
+  int srv = aDBConnection->prepareStatement(
+      aNativeConnection, PromiseFlatCString(aSQLStatement), &mDBStatement);
+  if (srv != SQLITE_OK) {
+    MOZ_LOG(gStorageLog, LogLevel::Error,
+            ("Sqlite statement prepare error: %d '%s'", srv,
+             ::sqlite3_errmsg(aNativeConnection)));
+    MOZ_LOG(gStorageLog, LogLevel::Error,
+            ("Statement was: '%s'", PromiseFlatCString(aSQLStatement).get()));
+
+    aDBConnection->RecordQueryStatus(srv);
+    mQueryStatusRecorded = true;
+    return convertResultCode(srv);
+  }
+
+  MOZ_LOG(gStorageLog, LogLevel::Debug,
+          ("Initialized statement '%s' (0x%p)",
+           PromiseFlatCString(aSQLStatement).get(), mDBStatement));
+
+  mDBConnection = aDBConnection;
+  mNativeConnection = aNativeConnection;
+  mParamCount = ::sqlite3_bind_parameter_count(mDBStatement);
+  mResultColumnCount = ::sqlite3_column_count(mDBStatement);
+  mColumnNames.Clear();
+
+  nsCString* columnNames = mColumnNames.AppendElements(mResultColumnCount);
+  for (uint32_t i = 0; i < mResultColumnCount; i++) {
+    const char* name = ::sqlite3_column_name(mDBStatement, i);
+    columnNames[i].Assign(name);
+  }
+
+#ifdef DEBUG
+  // We want to try and test for LIKE and that consumers are using
+  // escapeStringForLIKE instead of just trusting user input.  The idea to
+  // check to see if they are binding a parameter after like instead of just
+  // using a string.  We only do this in debug builds because it's expensive!
+  auto c = nsCaseInsensitiveCStringComparator;
+  nsACString::const_iterator start, end, e;
+  aSQLStatement.BeginReading(start);
+  aSQLStatement.EndReading(end);
+  e = end;
+  while (::FindInReadable(" LIKE"_ns, start, e, c)) {
+    // We have a LIKE in here, so we perform our tests
+    // FindInReadable moves the iterator, so we have to get a new one for
+    // each test we perform.
+    nsACString::const_iterator s1, s2, s3;
+    s1 = s2 = s3 = start;
+
+    if (!(::FindInReadable(" LIKE ?"_ns, s1, end, c) ||
+          ::FindInReadable(" LIKE :"_ns, s2, end, c) ||
+          ::FindInReadable(" LIKE @"_ns, s3, end, c))) {
+      // At this point, we didn't find a LIKE statement followed by ?, :,
+      // or @, all of which are valid characters for binding a parameter.
+      // We will warn the consumer that they may not be safely using LIKE.
+      NS_WARNING(
+          "Unsafe use of LIKE detected!  Please ensure that you "
+          "are using mozIStorageStatement::escapeStringForLIKE "
+          "and that you are binding that result to the statement "
+          "to prevent SQL injection attacks.");
+    }
+
+    // resetting start and e
+    start = e;
+    e = end;
+  }
+#endif
+
+  return NS_OK;
+}
+
+mozIStorageBindingParams* Statement::getParams() {
+  nsresult rv;
+
+  // If we do not have an array object yet, make it.
+  if (!mParamsArray) {
+    nsCOMPtr<mozIStorageBindingParamsArray> array;
+    rv = NewBindingParamsArray(getter_AddRefs(array));
+    NS_ENSURE_SUCCESS(rv, nullptr);
+
+    mParamsArray = static_cast<BindingParamsArray*>(array.get());
+  }
+
+  // If there isn't already any rows added, we'll have to add one to use.
+  if (mParamsArray->length() == 0) {
+    RefPtr<BindingParams> params(new BindingParams(mParamsArray, this));
+    NS_ENSURE_TRUE(params, nullptr);
+
+    rv = mParamsArray->AddParams(params);
+    NS_ENSURE_SUCCESS(rv, nullptr);
+
+    // We have to unlock our params because AddParams locks them.  This is safe
+    // because no reference to the params object was, or ever will be given out.
+    params->unlock(this);
+
+    // We also want to lock our array at this point - we don't want anything to
+    // be added to it.  Nothing has, or will ever get a reference to it, but we
+    // will get additional safety checks via assertions by doing this.
+    mParamsArray->lock();
+  }
+
+  return *mParamsArray->begin();
+}
+
+void Statement::MaybeRecordQueryStatus(int srv, bool isResetting) {
+  // If the statement hasn't been executed synchronously since it was last reset
+  // or created then there is no need to record anything. Asynchronous
+  // statements have their status tracked and recorded by StatementData.
+  if (!mHasExecuted) {
+    return;
+  }
+
+  if (!isResetting && !isErrorCode(srv)) {
+    // Non-errors will be recorded when finalizing.
+    return;
+  }
+
+  // We only record a status if no status has been recorded previously.
+  if (!mQueryStatusRecorded && mDBConnection) {
+    mDBConnection->RecordQueryStatus(srv);
+  }
+
+  // Allow another status to be recorded if we are resetting this statement.
+  mQueryStatusRecorded = !isResetting;
+}
+
+Statement::~Statement() { (void)internalFinalize(true); }
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsISupports
+
+NS_IMPL_ADDREF(Statement)
+NS_IMPL_RELEASE(Statement)
+
+NS_INTERFACE_MAP_BEGIN(Statement)
+  NS_INTERFACE_MAP_ENTRY(mozIStorageStatement)
+  NS_INTERFACE_MAP_ENTRY(mozIStorageBaseStatement)
+  NS_INTERFACE_MAP_ENTRY(mozIStorageBindingParams)
+  NS_INTERFACE_MAP_ENTRY(mozIStorageValueArray)
+  NS_INTERFACE_MAP_ENTRY(mozilla::storage::StorageBaseStatementInternal)
+  if (aIID.Equals(NS_GET_IID(nsIClassInfo))) {
+    foundInterface = static_cast<nsIClassInfo*>(&sStatementClassInfo);
+  } else
+    NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, mozIStorageStatement)
+NS_INTERFACE_MAP_END
+
+////////////////////////////////////////////////////////////////////////////////
+//// StorageBaseStatementInternal
+
+Connection* Statement::getOwner() { return mDBConnection; }
+
+int Statement::getAsyncStatement(sqlite3_stmt** _stmt) {
+  // If we have no statement, we shouldn't be calling this method!
+  NS_ASSERTION(mDBStatement != nullptr, "We have no statement to clone!");
+
+  // If we do not yet have a cached async statement, clone our statement now.
+  if (!mAsyncStatement) {
+    nsDependentCString sql(::sqlite3_sql(mDBStatement));
+    int rc = mDBConnection->prepareStatement(mNativeConnection, sql,
+                                             &mAsyncStatement);
+    if (rc != SQLITE_OK) {
+      mDBConnection->RecordQueryStatus(rc);
+      *_stmt = nullptr;
+      return rc;
+    }
+
+    MOZ_LOG(gStorageLog, LogLevel::Debug,
+            ("Cloned statement 0x%p to 0x%p", mDBStatement, mAsyncStatement));
+  }
+
+  *_stmt = mAsyncStatement;
+  return SQLITE_OK;
+}
+
+nsresult Statement::getAsynchronousStatementData(StatementData& _data) {
+  if (!mDBStatement) return NS_ERROR_UNEXPECTED;
+
+  sqlite3_stmt* stmt;
+  int rc = getAsyncStatement(&stmt);
+  if (rc != SQLITE_OK) return convertResultCode(rc);
+
+  _data = StatementData(stmt, bindingParamsArray(), this);
+
+  return NS_OK;
+}
+
+already_AddRefed<mozIStorageBindingParams> Statement::newBindingParams(
+    mozIStorageBindingParamsArray* aOwner) {
+  nsCOMPtr<mozIStorageBindingParams> params = new BindingParams(aOwner, this);
+  return params.forget();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// mozIStorageStatement
+
+// proxy to StorageBaseStatementInternal using its define helper.
+MIXIN_IMPL_STORAGEBASESTATEMENTINTERNAL(Statement, (void)0;)
+
+NS_IMETHODIMP
+Statement::Clone(mozIStorageStatement** _statement) {
+  RefPtr<Statement> statement(new Statement());
+  NS_ENSURE_TRUE(statement, NS_ERROR_OUT_OF_MEMORY);
+
+  nsAutoCString sql(::sqlite3_sql(mDBStatement));
+  nsresult rv = statement->initialize(mDBConnection, mNativeConnection, sql);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  statement.forget(_statement);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Statement::Finalize() { return internalFinalize(false); }
+
+nsresult Statement::internalFinalize(bool aDestructing) {
+  if (!mDBStatement) return NS_OK;
+
+  int srv = SQLITE_OK;
+
+  {
+    // If the statement ends up being finalized twice, the second finalization
+    // would apply to a dangling pointer and may cause unexpected consequences.
+    // Thus we must be sure that the connection state won't change during this
+    // operation, to avoid racing with finalizations made by the closing
+    // connection.  See Connection::internalClose().
+    MutexAutoLock lockedScope(mDBConnection->sharedAsyncExecutionMutex);
+    if (!mDBConnection->isClosed(lockedScope)) {
+      MOZ_LOG(gStorageLog, LogLevel::Debug,
+              ("Finalizing statement '%s' during garbage-collection",
+               ::sqlite3_sql(mDBStatement)));
+      srv = ::sqlite3_finalize(mDBStatement);
+    }
+#ifdef DEBUG
+    else {
+      // The database connection is closed. The sqlite
+      // statement has either been finalized already by the connection
+      // or is about to be finalized by the connection.
+      //
+      // Finalizing it here would be useless and segfaultish.
+      //
+      // Note that we can't display the statement itself, as the data structure
+      // is not valid anymore. However, the address shown here should help
+      // developers correlate with the more complete debug message triggered
+      // by AsyncClose().
+
+      SmprintfPointer msg = ::mozilla::Smprintf(
+          "SQL statement (%p) should have been finalized"
+          " before garbage-collection. For more details on this statement, set"
+          " NSPR_LOG_MESSAGES=mozStorage:5 .",
+          mDBStatement);
+      NS_WARNING(msg.get());
+
+      // Use %s so we aren't exposing random strings to printf interpolation.
+      MOZ_LOG(gStorageLog, LogLevel::Warning, ("%s", msg.get()));
+    }
+#endif  // DEBUG
+  }
+
+  // This will be a no-op if the status has already been recorded or if this
+  // statement has not been executed. Async statements have their status
+  // tracked and recorded in StatementData.
+  MaybeRecordQueryStatus(srv, true);
+
+  mDBStatement = nullptr;
+
+  if (mAsyncStatement) {
+    // If the destructor called us, there are no pending async statements (they
+    // hold a reference to us) and we can/must just kill the statement directly.
+    if (aDestructing)
+      destructorAsyncFinalize();
+    else
+      asyncFinalize();
+  }
+
+  // Release the holders, so they can release the reference to us.
+  mStatementParamsHolder = nullptr;
+  mStatementRowHolder = nullptr;
+
+  return convertResultCode(srv);
+}
+
+NS_IMETHODIMP
+Statement::GetParameterCount(uint32_t* _parameterCount) {
+  if (!mDBStatement) return NS_ERROR_NOT_INITIALIZED;
+
+  *_parameterCount = mParamCount;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Statement::GetParameterName(uint32_t aParamIndex, nsACString& _name) {
+  if (!mDBStatement) return NS_ERROR_NOT_INITIALIZED;
+  ENSURE_INDEX_VALUE(aParamIndex, mParamCount);
+
+  const char* name =
+      ::sqlite3_bind_parameter_name(mDBStatement, aParamIndex + 1);
+  if (name == nullptr) {
+    // this thing had no name, so fake one
+    nsAutoCString fakeName(":");
+    fakeName.AppendInt(aParamIndex);
+    _name.Assign(fakeName);
+  } else {
+    _name.Assign(nsDependentCString(name));
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Statement::GetParameterIndex(const nsACString& aName, uint32_t* _index) {
+  if (!mDBStatement) return NS_ERROR_NOT_INITIALIZED;
+
+  // We do not accept any forms of names other than ":name", but we need to add
+  // the colon for SQLite.
+  nsAutoCString name(":");
+  name.Append(aName);
+  int ind = ::sqlite3_bind_parameter_index(mDBStatement, name.get());
+  if (ind == 0)  // Named parameter not found.
+    return NS_ERROR_INVALID_ARG;
+
+  *_index = ind - 1;  // SQLite indexes are 1-based, we are 0-based.
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Statement::GetColumnCount(uint32_t* _columnCount) {
+  if (!mDBStatement) return NS_ERROR_NOT_INITIALIZED;
+
+  *_columnCount = mResultColumnCount;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Statement::GetColumnName(uint32_t aColumnIndex, nsACString& _name) {
+  if (!mDBStatement) return NS_ERROR_NOT_INITIALIZED;
+  ENSURE_INDEX_VALUE(aColumnIndex, mResultColumnCount);
+
+  const char* cname = ::sqlite3_column_name(mDBStatement, aColumnIndex);
+  _name.Assign(nsDependentCString(cname));
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Statement::GetColumnIndex(const nsACString& aName, uint32_t* _index) {
+  if (!mDBStatement) return NS_ERROR_NOT_INITIALIZED;
+
+  // Surprisingly enough, SQLite doesn't provide an API for this.  We have to
+  // determine it ourselves sadly.
+  for (uint32_t i = 0; i < mResultColumnCount; i++) {
+    if (mColumnNames[i].Equals(aName)) {
+      *_index = i;
+      return NS_OK;
+    }
+  }
+
+  return NS_ERROR_INVALID_ARG;
+}
+
+NS_IMETHODIMP
+Statement::Reset() {
+  if (!mDBStatement) return NS_ERROR_NOT_INITIALIZED;
+
+#ifdef DEBUG
+  MOZ_LOG(gStorageLog, LogLevel::Debug,
+          ("Resetting statement: '%s'", ::sqlite3_sql(mDBStatement)));
+
+  checkAndLogStatementPerformance(mDBStatement);
+#endif
+
+  mParamsArray = nullptr;
+  (void)sqlite3_reset(mDBStatement);
+  (void)sqlite3_clear_bindings(mDBStatement);
+
+  mExecuting = false;
+
+  // This will be a no-op if the status has already been recorded or if this
+  // statement has not been executed. Async statements have their status
+  // tracked and recorded in StatementData.
+  MaybeRecordQueryStatus(SQLITE_OK, true);
+  mHasExecuted = false;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Statement::BindParameters(mozIStorageBindingParamsArray* aParameters) {
+  NS_ENSURE_ARG_POINTER(aParameters);
+
+  if (!mDBStatement) return NS_ERROR_NOT_INITIALIZED;
+
+  BindingParamsArray* array = static_cast<BindingParamsArray*>(aParameters);
+  if (array->getOwner() != this) return NS_ERROR_UNEXPECTED;
+
+  if (array->length() == 0) return NS_ERROR_UNEXPECTED;
+
+  mParamsArray = array;
+  mParamsArray->lock();
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Statement::Execute() {
+  if (!mDBStatement) return NS_ERROR_NOT_INITIALIZED;
+
+  bool ret;
+  nsresult rv = ExecuteStep(&ret);
+  nsresult rv2 = Reset();
+
+  return NS_FAILED(rv) ? rv : rv2;
+}
+
+NS_IMETHODIMP
+Statement::ExecuteStep(bool* _moreResults) {
+  AUTO_PROFILER_LABEL("Statement::ExecuteStep", OTHER);
+
+  if (!mDBStatement) return NS_ERROR_NOT_INITIALIZED;
+
+  // Bind any parameters first before executing.
+  if (mParamsArray) {
+    // If we have more than one row of parameters to bind, they shouldn't be
+    // calling this method (and instead use executeAsync).
+    if (mParamsArray->length() != 1) return NS_ERROR_UNEXPECTED;
+
+    BindingParamsArray::iterator row = mParamsArray->begin();
+    nsCOMPtr<IStorageBindingParamsInternal> bindingInternal =
+        do_QueryInterface(*row);
+    nsCOMPtr<mozIStorageError> error = bindingInternal->bind(mDBStatement);
+    if (error) {
+      int32_t srv;
+      (void)error->GetResult(&srv);
+      return convertResultCode(srv);
+    }
+
+    // We have bound, so now we can clear our array.
+    mParamsArray = nullptr;
+  }
+  int srv = mDBConnection->stepStatement(mNativeConnection, mDBStatement);
+  mHasExecuted = true;
+  MaybeRecordQueryStatus(srv);
+
+  if (srv != SQLITE_ROW && srv != SQLITE_DONE &&
+      MOZ_LOG_TEST(gStorageLog, LogLevel::Debug)) {
+    nsAutoCString errStr;
+    (void)mDBConnection->GetLastErrorString(errStr);
+    MOZ_LOG(gStorageLog, LogLevel::Debug,
+            ("Statement::ExecuteStep error: %s", errStr.get()));
+  }
+
+  // SQLITE_ROW and SQLITE_DONE are non-errors
+  if (srv == SQLITE_ROW) {
+    // we got a row back
+    mExecuting = true;
+    *_moreResults = true;
+    return NS_OK;
+  } else if (srv == SQLITE_DONE) {
+    // statement is done (no row returned)
+    mExecuting = false;
+    *_moreResults = false;
+    return NS_OK;
+  } else if (srv == SQLITE_BUSY || srv == SQLITE_MISUSE) {
+    mExecuting = false;
+  } else if (mExecuting) {
+    MOZ_LOG(gStorageLog, LogLevel::Error,
+            ("SQLite error after mExecuting was true!"));
+    mExecuting = false;
+  }
+
+  return convertResultCode(srv);
+}
+
+NS_IMETHODIMP
+Statement::GetState(int32_t* _state) {
+  if (!mDBStatement)
+    *_state = MOZ_STORAGE_STATEMENT_INVALID;
+  else if (mExecuting)
+    *_state = MOZ_STORAGE_STATEMENT_EXECUTING;
+  else
+    *_state = MOZ_STORAGE_STATEMENT_READY;
+
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// mozIStorageValueArray (now part of mozIStorageStatement too)
+
+NS_IMETHODIMP
+Statement::GetNumEntries(uint32_t* _length) {
+  *_length = mResultColumnCount;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Statement::GetTypeOfIndex(uint32_t aIndex, int32_t* _type) {
+  if (!mDBStatement) return NS_ERROR_NOT_INITIALIZED;
+
+  ENSURE_INDEX_VALUE(aIndex, mResultColumnCount);
+
+  if (!mExecuting) return NS_ERROR_UNEXPECTED;
+
+  int t = ::sqlite3_column_type(mDBStatement, aIndex);
+  switch (t) {
+    case SQLITE_INTEGER:
+      *_type = mozIStorageStatement::VALUE_TYPE_INTEGER;
+      break;
+    case SQLITE_FLOAT:
+      *_type = mozIStorageStatement::VALUE_TYPE_FLOAT;
+      break;
+    case SQLITE_TEXT:
+      *_type = mozIStorageStatement::VALUE_TYPE_TEXT;
+      break;
+    case SQLITE_BLOB:
+      *_type = mozIStorageStatement::VALUE_TYPE_BLOB;
+      break;
+    case SQLITE_NULL:
+      *_type = mozIStorageStatement::VALUE_TYPE_NULL;
+      break;
+    default:
+      return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Statement::GetInt32(uint32_t aIndex, int32_t* _value) {
+  if (!mDBStatement) return NS_ERROR_NOT_INITIALIZED;
+
+  ENSURE_INDEX_VALUE(aIndex, mResultColumnCount);
+
+  if (!mExecuting) return NS_ERROR_UNEXPECTED;
+
+  *_value = ::sqlite3_column_int(mDBStatement, aIndex);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Statement::GetInt64(uint32_t aIndex, int64_t* _value) {
+  if (!mDBStatement) return NS_ERROR_NOT_INITIALIZED;
+
+  ENSURE_INDEX_VALUE(aIndex, mResultColumnCount);
+
+  if (!mExecuting) return NS_ERROR_UNEXPECTED;
+
+  *_value = ::sqlite3_column_int64(mDBStatement, aIndex);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Statement::GetDouble(uint32_t aIndex, double* _value) {
+  if (!mDBStatement) return NS_ERROR_NOT_INITIALIZED;
+
+  ENSURE_INDEX_VALUE(aIndex, mResultColumnCount);
+
+  if (!mExecuting) return NS_ERROR_UNEXPECTED;
+
+  *_value = ::sqlite3_column_double(mDBStatement, aIndex);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Statement::GetUTF8String(uint32_t aIndex, nsACString& _value) {
+  // Get type of Index will check aIndex for us, so we don't have to.
+  int32_t type;
+  nsresult rv = GetTypeOfIndex(aIndex, &type);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (type == mozIStorageStatement::VALUE_TYPE_NULL) {
+    // NULL columns should have IsVoid set to distinguish them from the empty
+    // string.
+    _value.SetIsVoid(true);
+  } else {
+    const char* value = reinterpret_cast<const char*>(
+        ::sqlite3_column_text(mDBStatement, aIndex));
+    _value.Assign(value, ::sqlite3_column_bytes(mDBStatement, aIndex));
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Statement::GetString(uint32_t aIndex, nsAString& _value) {
+  // Get type of Index will check aIndex for us, so we don't have to.
+  int32_t type;
+  nsresult rv = GetTypeOfIndex(aIndex, &type);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (type == mozIStorageStatement::VALUE_TYPE_NULL) {
+    // NULL columns should have IsVoid set to distinguish them from the empty
+    // string.
+    _value.SetIsVoid(true);
+  } else {
+    const char16_t* value = static_cast<const char16_t*>(
+        ::sqlite3_column_text16(mDBStatement, aIndex));
+    _value.Assign(value, ::sqlite3_column_bytes16(mDBStatement, aIndex) /
+                             sizeof(char16_t));
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Statement::GetVariant(uint32_t aIndex, nsIVariant** _value) {
+  if (!mDBStatement) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  ENSURE_INDEX_VALUE(aIndex, mResultColumnCount);
+
+  if (!mExecuting) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsCOMPtr<nsIVariant> variant;
+  int type = ::sqlite3_column_type(mDBStatement, aIndex);
+  switch (type) {
+    case SQLITE_INTEGER:
+      variant =
+          new IntegerVariant(::sqlite3_column_int64(mDBStatement, aIndex));
+      break;
+    case SQLITE_FLOAT:
+      variant = new FloatVariant(::sqlite3_column_double(mDBStatement, aIndex));
+      break;
+    case SQLITE_TEXT: {
+      const char16_t* value = static_cast<const char16_t*>(
+          ::sqlite3_column_text16(mDBStatement, aIndex));
+      nsDependentString str(
+          value,
+          ::sqlite3_column_bytes16(mDBStatement, aIndex) / sizeof(char16_t));
+      variant = new TextVariant(str);
+      break;
+    }
+    case SQLITE_NULL:
+      variant = new NullVariant();
+      break;
+    case SQLITE_BLOB: {
+      int size = ::sqlite3_column_bytes(mDBStatement, aIndex);
+      const void* data = ::sqlite3_column_blob(mDBStatement, aIndex);
+      variant = new BlobVariant(std::pair<const void*, int>(data, size));
+      break;
+    }
+  }
+  NS_ENSURE_TRUE(variant, NS_ERROR_UNEXPECTED);
+
+  variant.forget(_value);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Statement::GetBlob(uint32_t aIndex, uint32_t* _size, uint8_t** _blob) {
+  if (!mDBStatement) return NS_ERROR_NOT_INITIALIZED;
+
+  ENSURE_INDEX_VALUE(aIndex, mResultColumnCount);
+
+  if (!mExecuting) return NS_ERROR_UNEXPECTED;
+
+  int size = ::sqlite3_column_bytes(mDBStatement, aIndex);
+  void* blob = nullptr;
+  if (size) {
+    blob = moz_xmemdup(::sqlite3_column_blob(mDBStatement, aIndex), size);
+  }
+
+  *_blob = static_cast<uint8_t*>(blob);
+  *_size = size;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Statement::GetBlobAsString(uint32_t aIndex, nsAString& aValue) {
+  return DoGetBlobAsString(this, aIndex, aValue);
+}
+
+NS_IMETHODIMP
+Statement::GetBlobAsUTF8String(uint32_t aIndex, nsACString& aValue) {
+  return DoGetBlobAsString(this, aIndex, aValue);
+}
+
+NS_IMETHODIMP
+Statement::GetSharedUTF8String(uint32_t aIndex, uint32_t* _byteLength,
+                               const char** _value) {
+  *_value = reinterpret_cast<const char*>(
+      ::sqlite3_column_text(mDBStatement, aIndex));
+  if (_byteLength) {
+    *_byteLength = ::sqlite3_column_bytes(mDBStatement, aIndex);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Statement::GetSharedString(uint32_t aIndex, uint32_t* _byteLength,
+                           const char16_t** _value) {
+  *_value = static_cast<const char16_t*>(
+      ::sqlite3_column_text16(mDBStatement, aIndex));
+  if (_byteLength) {
+    *_byteLength = ::sqlite3_column_bytes16(mDBStatement, aIndex);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Statement::GetSharedBlob(uint32_t aIndex, uint32_t* _byteLength,
+                         const uint8_t** _blob) {
+  *_blob =
+      static_cast<const uint8_t*>(::sqlite3_column_blob(mDBStatement, aIndex));
+  if (_byteLength) {
+    *_byteLength = ::sqlite3_column_bytes(mDBStatement, aIndex);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Statement::GetIsNull(uint32_t aIndex, bool* _isNull) {
+  // Get type of Index will check aIndex for us, so we don't have to.
+  int32_t type;
+  nsresult rv = GetTypeOfIndex(aIndex, &type);
+  NS_ENSURE_SUCCESS(rv, rv);
+  *_isNull = (type == mozIStorageStatement::VALUE_TYPE_NULL);
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// mozIStorageBindingParams
+
+BOILERPLATE_BIND_PROXIES(Statement,
+                         if (!mDBStatement) return NS_ERROR_NOT_INITIALIZED;)
+
+}  // namespace storage
+}  // namespace mozilla
diff --git a/storage/mozStorageStatement.h b/storage/mozStorageStatement.h
new file mode 100644
index 0000000000..e472a804c2
--- /dev/null
+++ b/storage/mozStorageStatement.h
@@ -0,0 +1,132 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozStorageStatement_h
+#define mozStorageStatement_h
+
+#include "nsString.h"
+
+#include "nsTArray.h"
+
+#include "mozStorageBindingParamsArray.h"
+#include "mozStorageStatementData.h"
+#include "mozIStorageStatement.h"
+#include "mozIStorageValueArray.h"
+#include "StorageBaseStatementInternal.h"
+#include "mozilla/Attributes.h"
+
+struct sqlite3_stmt;
+
+namespace mozilla {
+namespace storage {
+class StatementJSHelper;
+class Connection;
+class StatementParamsHolder;
+class StatementRowHolder;
+
+class Statement final : public mozIStorageStatement,
+                        public mozIStorageValueArray,
+                        public StorageBaseStatementInternal {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGESTATEMENT
+  NS_DECL_MOZISTORAGEBASESTATEMENT
+  NS_DECL_MOZISTORAGEBINDINGPARAMS
+  // NS_DECL_MOZISTORAGEVALUEARRAY (methods in mozIStorageStatement)
+  NS_DECL_STORAGEBASESTATEMENTINTERNAL
+
+  Statement();
+
+  /**
+   * Initializes the object on aDBConnection by preparing the SQL statement
+   * given by aSQLStatement.
+   *
+   * @param aDBConnection
+   *        The Connection object this statement is associated with.
+   * @param aNativeConnection
+   *        The native Sqlite connection this statement is associated with.
+   * @param aSQLStatement
+   *        The SQL statement to prepare that this object will represent.
+   */
+  nsresult initialize(Connection* aDBConnection, sqlite3* aNativeConnection,
+                      const nsACString& aSQLStatement);
+
+  /**
+   * Obtains the native statement pointer.
+   */
+  inline sqlite3_stmt* nativeStatement() { return mDBStatement; }
+
+  /**
+   * Obtains and transfers ownership of the array of parameters that are bound
+   * to this statment.  This can be null.
+   */
+  inline already_AddRefed<BindingParamsArray> bindingParamsArray() {
+    return mParamsArray.forget();
+  }
+
+ private:
+  ~Statement();
+
+  sqlite3_stmt* mDBStatement;
+  uint32_t mParamCount;
+  uint32_t mResultColumnCount;
+  nsTArray<nsCString> mColumnNames;
+  bool mExecuting;
+
+  // Tracks whether the status for this statement has been recorded since it was
+  // last reset or created.
+  bool mQueryStatusRecorded;
+  // Tracks whether this statement has been executed since it was last reset or
+  // created.
+  bool mHasExecuted;
+
+  /**
+   * @return a pointer to the BindingParams object to use with our Bind*
+   *         method.
+   */
+  mozIStorageBindingParams* getParams();
+
+  /**
+   * Records a query status result in telemetry. If a result has already been
+   * recorded for this statement then this does nothing. Otherwise the result
+   * is recorded if it is an error or if this is the final result.
+   */
+  void MaybeRecordQueryStatus(int srv, bool isResetting = false);
+
+  /**
+   * Holds the array of parameters to bind to this statement when we execute
+   * it asynchronously.
+   */
+  RefPtr<BindingParamsArray> mParamsArray;
+
+  /**
+   * The following two members are only used with the JS helper.  They cache
+   * the row and params objects.
+   */
+  nsMainThreadPtrHandle<StatementParamsHolder> mStatementParamsHolder;
+  nsMainThreadPtrHandle<StatementRowHolder> mStatementRowHolder;
+
+  /**
+   * Internal version of finalize that allows us to tell it if it is being
+   * called from the destructor so it can know not to dispatch events that
+   * require a reference to us.
+   *
+   * @param aDestructing
+   *        Is the destructor calling?
+   */
+  nsresult internalFinalize(bool aDestructing);
+
+  friend class StatementJSHelper;
+};
+
+inline nsISupports* ToSupports(Statement* p) {
+  return NS_ISUPPORTS_CAST(mozIStorageStatement*, p);
+}
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif  // mozStorageStatement_h
diff --git a/storage/mozStorageStatementData.h b/storage/mozStorageStatementData.h
new file mode 100644
index 0000000000..1008496671
--- /dev/null
+++ b/storage/mozStorageStatementData.h
@@ -0,0 +1,143 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 sts=2 et
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozStorageStatementData_h
+#define mozStorageStatementData_h
+
+#include "sqlite3.h"
+
+#include "nsTArray.h"
+#include "MainThreadUtils.h"
+
+#include "mozStorageBindingParamsArray.h"
+#include "mozStorageConnection.h"
+#include "StorageBaseStatementInternal.h"
+#include "mozStoragePrivateHelpers.h"
+
+struct sqlite3_stmt;
+
+namespace mozilla {
+namespace storage {
+
+class StatementData {
+ public:
+  StatementData(sqlite3_stmt* aStatement,
+                already_AddRefed<BindingParamsArray> aParamsArray,
+                StorageBaseStatementInternal* aStatementOwner)
+      : mStatement(aStatement),
+        mParamsArray(aParamsArray),
+        mQueryStatusRecorded(false),
+        mStatementOwner(aStatementOwner) {
+    MOZ_ASSERT(mStatementOwner, "Must have a statement owner!");
+  }
+  StatementData(const StatementData& aSource)
+      : mStatement(aSource.mStatement),
+        mParamsArray(aSource.mParamsArray),
+        mQueryStatusRecorded(false),
+        mStatementOwner(aSource.mStatementOwner) {
+    MOZ_ASSERT(mStatementOwner, "Must have a statement owner!");
+  }
+  StatementData() : mStatement(nullptr), mQueryStatusRecorded(false) {}
+  ~StatementData() {
+    // We need to ensure that mParamsArray is released on the main thread,
+    // as the binding arguments may be XPConnect values, which are safe
+    // to release only on the main thread.
+    NS_ReleaseOnMainThread("StatementData::mParamsArray",
+                           mParamsArray.forget());
+  }
+
+  /**
+   * Return the sqlite statement, fetching it from the storage statement.  In
+   * the case of AsyncStatements this may actually create the statement
+   */
+  inline int getSqliteStatement(sqlite3_stmt** _stmt) {
+    if (!mStatement) {
+      int rc = mStatementOwner->getAsyncStatement(&mStatement);
+      MaybeRecordQueryStatus(rc);
+      NS_ENSURE_TRUE(rc == SQLITE_OK, rc);
+    }
+    *_stmt = mStatement;
+    return SQLITE_OK;
+  }
+
+  operator BindingParamsArray*() const { return mParamsArray; }
+
+  /**
+   * NULLs out our sqlite3_stmt (it is held by the owner) after reseting it and
+   * clear all bindings to it.  This is expected to occur on the async thread.
+   */
+  inline void reset() {
+    MOZ_ASSERT(mStatementOwner, "Must have a statement owner!");
+    // In the AsyncStatement case we may never have populated mStatement if the
+    // AsyncExecuteStatements got canceled or a failure occurred in constructing
+    // the statement.
+    if (mStatement) {
+      (void)::sqlite3_reset(mStatement);
+      (void)::sqlite3_clear_bindings(mStatement);
+      mStatement = nullptr;
+
+      if (!mQueryStatusRecorded) {
+        mStatementOwner->getOwner()->RecordQueryStatus(SQLITE_OK);
+      }
+    }
+  }
+
+  /**
+   * Indicates if this statement has parameters to be bound before it is
+   * executed.
+   *
+   * @return true if the statement has parameters to bind against, false
+   *         otherwise.
+   */
+  inline bool hasParametersToBeBound() const { return !!mParamsArray; }
+  /**
+   * Indicates the number of implicit statements generated by this statement
+   * requiring a transaction for execution.  For example a single statement
+   * with N BindingParams will execute N implicit staments.
+   *
+   * @return number of statements requiring a transaction for execution.
+   *
+   * @note In the case of AsyncStatements this may actually create the
+   *       statement.
+   */
+  inline uint32_t needsTransaction() {
+    MOZ_ASSERT(!NS_IsMainThread());
+    // Be sure to use the getSqliteStatement helper, since sqlite3_stmt_readonly
+    // can only analyze prepared statements and AsyncStatements are prepared
+    // lazily.
+    sqlite3_stmt* stmt;
+    int rc = getSqliteStatement(&stmt);
+    if (SQLITE_OK != rc || ::sqlite3_stmt_readonly(stmt)) {
+      return 0;
+    }
+    return mParamsArray ? mParamsArray->length() : 1;
+  }
+
+  void MaybeRecordQueryStatus(int srv) {
+    if (mQueryStatusRecorded || !isErrorCode(srv)) {
+      return;
+    }
+
+    mStatementOwner->getOwner()->RecordQueryStatus(srv);
+    mQueryStatusRecorded = true;
+  }
+
+ private:
+  sqlite3_stmt* mStatement;
+  RefPtr<BindingParamsArray> mParamsArray;
+  bool mQueryStatusRecorded;
+
+  /**
+   * We hold onto a reference of the statement's owner so it doesn't get
+   * destroyed out from under us.
+   */
+  nsCOMPtr<StorageBaseStatementInternal> mStatementOwner;
+};
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif  // mozStorageStatementData_h
diff --git a/storage/mozStorageStatementJSHelper.cpp b/storage/mozStorageStatementJSHelper.cpp
new file mode 100644
index 0000000000..c891e955a2
--- /dev/null
+++ b/storage/mozStorageStatementJSHelper.cpp
@@ -0,0 +1,258 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsIXPConnect.h"
+#include "mozStorageStatement.h"
+#include "mozStorageService.h"
+
+#include "nsString.h"
+#include "nsServiceManagerUtils.h"
+
+#include "mozStorageStatementJSHelper.h"
+
+#include "mozStorageStatementRow.h"
+#include "mozStorageStatementParams.h"
+
+#include "jsapi.h"
+#include "js/PropertyAndElement.h"  // JS_DefineFunction, JS_DefineProperty, JS_DefinePropertyById
+#include "js/Value.h"
+
+#include "xpc_make_class.h"
+
+namespace mozilla {
+namespace storage {
+
+////////////////////////////////////////////////////////////////////////////////
+//// Global Functions
+
+static bool stepFunc(JSContext* aCtx, uint32_t argc, JS::Value* _vp) {
+  JS::CallArgs args = CallArgsFromVp(argc, _vp);
+
+  nsCOMPtr<nsIXPConnect> xpc(nsIXPConnect::XPConnect());
+  nsCOMPtr<nsIXPConnectWrappedNative> wrapper;
+
+  if (!args.thisv().isObject()) {
+    ::JS_ReportErrorASCII(aCtx, "mozIStorageStatement::step() requires object");
+    return false;
+  }
+
+  JS::Rooted<JSObject*> obj(aCtx, &args.thisv().toObject());
+  nsresult rv =
+      xpc->GetWrappedNativeOfJSObject(aCtx, obj, getter_AddRefs(wrapper));
+  if (NS_FAILED(rv)) {
+    ::JS_ReportErrorASCII(
+        aCtx, "mozIStorageStatement::step() could not obtain native statement");
+    return false;
+  }
+
+#ifdef DEBUG
+  {
+    nsCOMPtr<mozIStorageStatement> isStatement(
+        do_QueryInterface(wrapper->Native()));
+    NS_ASSERTION(isStatement, "How is this not a statement?!");
+  }
+#endif
+
+  Statement* stmt = static_cast<Statement*>(
+      static_cast<mozIStorageStatement*>(wrapper->Native()));
+
+  bool hasMore = false;
+  rv = stmt->ExecuteStep(&hasMore);
+  if (NS_SUCCEEDED(rv) && !hasMore) {
+    args.rval().setBoolean(false);
+    (void)stmt->Reset();
+    return true;
+  }
+
+  if (NS_FAILED(rv)) {
+    ::JS_ReportErrorASCII(aCtx,
+                          "mozIStorageStatement::step() returned an error");
+    return false;
+  }
+
+  args.rval().setBoolean(hasMore);
+  return true;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// StatementJSHelper
+
+nsresult StatementJSHelper::getRow(Statement* aStatement, JSContext* aCtx,
+                                   JSObject* aScopeObj, JS::Value* _row) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+#ifdef DEBUG
+  int32_t state;
+  (void)aStatement->GetState(&state);
+  NS_ASSERTION(state == mozIStorageStatement::MOZ_STORAGE_STATEMENT_EXECUTING,
+               "Invalid state to get the row object - all calls will fail!");
+#endif
+
+  JS::Rooted<JSObject*> scope(aCtx, aScopeObj);
+
+  if (!aStatement->mStatementRowHolder) {
+    dom::GlobalObject global(aCtx, scope);
+    if (global.Failed()) {
+      return NS_ERROR_UNEXPECTED;
+    }
+
+    nsCOMPtr<nsPIDOMWindowInner> window =
+        do_QueryInterface(global.GetAsSupports());
+
+    RefPtr<StatementRow> row(new StatementRow(window, aStatement));
+    NS_ENSURE_TRUE(row, NS_ERROR_OUT_OF_MEMORY);
+
+    RefPtr<StatementRowHolder> rowHolder = new StatementRowHolder(row);
+    NS_ENSURE_TRUE(rowHolder, NS_ERROR_OUT_OF_MEMORY);
+
+    aStatement->mStatementRowHolder =
+        new nsMainThreadPtrHolder<StatementRowHolder>(
+            "Statement::mStatementRowHolder", rowHolder);
+  }
+
+  RefPtr<StatementRow> row(aStatement->mStatementRowHolder->Get());
+  JSObject* obj = row->WrapObject(aCtx, nullptr);
+  if (!obj) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  _row->setObject(*obj);
+  return NS_OK;
+}
+
+nsresult StatementJSHelper::getParams(Statement* aStatement, JSContext* aCtx,
+                                      JSObject* aScopeObj, JS::Value* _params) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+#ifdef DEBUG
+  int32_t state;
+  (void)aStatement->GetState(&state);
+  NS_ASSERTION(state == mozIStorageStatement::MOZ_STORAGE_STATEMENT_READY,
+               "Invalid state to get the params object - all calls will fail!");
+#endif
+
+  JS::Rooted<JSObject*> scope(aCtx, aScopeObj);
+
+  if (!aStatement->mStatementParamsHolder) {
+    dom::GlobalObject global(aCtx, scope);
+    if (global.Failed()) {
+      return NS_ERROR_UNEXPECTED;
+    }
+
+    nsCOMPtr<nsPIDOMWindowInner> window =
+        do_QueryInterface(global.GetAsSupports());
+
+    RefPtr<StatementParams> params(new StatementParams(window, aStatement));
+    NS_ENSURE_TRUE(params, NS_ERROR_OUT_OF_MEMORY);
+
+    RefPtr<StatementParamsHolder> paramsHolder =
+        new StatementParamsHolder(params);
+    NS_ENSURE_TRUE(paramsHolder, NS_ERROR_OUT_OF_MEMORY);
+
+    aStatement->mStatementParamsHolder =
+        new nsMainThreadPtrHolder<StatementParamsHolder>(
+            "Statement::mStatementParamsHolder", paramsHolder);
+  }
+
+  RefPtr<StatementParams> params(aStatement->mStatementParamsHolder->Get());
+  JSObject* obj = params->WrapObject(aCtx, nullptr);
+  if (!obj) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  _params->setObject(*obj);
+  return NS_OK;
+}
+
+NS_IMETHODIMP_(MozExternalRefCountType) StatementJSHelper::AddRef() {
+  return 2;
+}
+NS_IMETHODIMP_(MozExternalRefCountType) StatementJSHelper::Release() {
+  return 1;
+}
+NS_INTERFACE_MAP_BEGIN(StatementJSHelper)
+  NS_INTERFACE_MAP_ENTRY(nsIXPCScriptable)
+  NS_INTERFACE_MAP_ENTRY(nsISupports)
+NS_INTERFACE_MAP_END
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsIXPCScriptable
+
+#define XPC_MAP_CLASSNAME StatementJSHelper
+#define XPC_MAP_QUOTED_CLASSNAME "StatementJSHelper"
+#define XPC_MAP_FLAGS \
+  (XPC_SCRIPTABLE_WANT_RESOLVE | XPC_SCRIPTABLE_ALLOW_PROP_MODS_DURING_RESOLVE)
+#include "xpc_map_end.h"
+
+NS_IMETHODIMP
+StatementJSHelper::Resolve(nsIXPConnectWrappedNative* aWrapper, JSContext* aCtx,
+                           JSObject* aScopeObj, jsid aId, bool* aResolvedp,
+                           bool* _retval) {
+  if (!aId.isString()) return NS_OK;
+
+  JS::Rooted<JSObject*> scope(aCtx, aScopeObj);
+  JS::Rooted<jsid> id(aCtx, aId);
+
+#ifdef DEBUG
+  {
+    nsCOMPtr<mozIStorageStatement> isStatement(
+        do_QueryInterface(aWrapper->Native()));
+    NS_ASSERTION(isStatement, "How is this not a statement?!");
+  }
+#endif
+
+  Statement* stmt = static_cast<Statement*>(
+      static_cast<mozIStorageStatement*>(aWrapper->Native()));
+
+  JSLinearString* str = id.toLinearString();
+  if (::JS_LinearStringEqualsLiteral(str, "step")) {
+    *_retval = ::JS_DefineFunction(aCtx, scope, "step", stepFunc, 0,
+                                   JSPROP_RESOLVING) != nullptr;
+    *aResolvedp = true;
+    return NS_OK;
+  }
+
+  JS::Rooted<JS::Value> val(aCtx);
+
+  if (::JS_LinearStringEqualsLiteral(str, "row")) {
+    nsresult rv = getRow(stmt, aCtx, scope, val.address());
+    NS_ENSURE_SUCCESS(rv, rv);
+    *_retval = ::JS_DefinePropertyById(aCtx, scope, id, val, JSPROP_RESOLVING);
+    *aResolvedp = true;
+    return NS_OK;
+  }
+
+  if (::JS_LinearStringEqualsLiteral(str, "params")) {
+    nsresult rv = getParams(stmt, aCtx, scope, val.address());
+    NS_ENSURE_SUCCESS(rv, rv);
+    *_retval = ::JS_DefinePropertyById(aCtx, scope, id, val, JSPROP_RESOLVING);
+    *aResolvedp = true;
+    return NS_OK;
+  }
+
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS0(StatementParamsHolder);
+
+StatementParamsHolder::~StatementParamsHolder() {
+  MOZ_ASSERT(NS_IsMainThread());
+  // We are considered dead at this point, so any wrappers for row or params
+  // need to lose their reference to the statement.
+  mParams->mStatement = nullptr;
+}
+
+NS_IMPL_ISUPPORTS0(StatementRowHolder);
+
+StatementRowHolder::~StatementRowHolder() {
+  MOZ_ASSERT(NS_IsMainThread());
+  // We are considered dead at this point, so any wrappers for row or params
+  // need to lose their reference to the statement.
+  mRow->mStatement = nullptr;
+}
+
+}  // namespace storage
+}  // namespace mozilla
diff --git a/storage/mozStorageStatementJSHelper.h b/storage/mozStorageStatementJSHelper.h
new file mode 100644
index 0000000000..0061d7d6a0
--- /dev/null
+++ b/storage/mozStorageStatementJSHelper.h
@@ -0,0 +1,73 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef MOZSTORAGESTATEMENTJSHELPER_H
+#define MOZSTORAGESTATEMENTJSHELPER_H
+
+#include "nsIXPCScriptable.h"
+
+class Statement;
+
+namespace mozilla {
+namespace storage {
+
+class StatementParams;
+class StatementRow;
+
+class StatementJSHelper : public nsIXPCScriptable {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIXPCSCRIPTABLE
+
+ private:
+  nsresult getRow(Statement*, JSContext*, JSObject*, JS::Value*);
+  nsresult getParams(Statement*, JSContext*, JSObject*, JS::Value*);
+};
+
+/**
+ * Wrappers used to clean up the references JS helpers hold to the statement.
+ * For cycle-avoidance reasons they do not hold reference-counted references,
+ * so it is important we do this.
+ */
+
+class StatementParamsHolder final : public nsISupports {
+ public:
+  NS_DECL_ISUPPORTS
+
+  explicit StatementParamsHolder(StatementParams* aParams) : mParams(aParams) {}
+
+  StatementParams* Get() const {
+    MOZ_ASSERT(mParams);
+    return mParams;
+  }
+
+ private:
+  virtual ~StatementParamsHolder();
+
+  RefPtr<StatementParams> mParams;
+};
+
+class StatementRowHolder final : public nsISupports {
+ public:
+  NS_DECL_ISUPPORTS
+
+  explicit StatementRowHolder(StatementRow* aRow) : mRow(aRow) {}
+
+  StatementRow* Get() const {
+    MOZ_ASSERT(mRow);
+    return mRow;
+  }
+
+ private:
+  virtual ~StatementRowHolder();
+
+  RefPtr<StatementRow> mRow;
+};
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif  // MOZSTORAGESTATEMENTJSHELPER_H
diff --git a/storage/mozStorageStatementParams.cpp b/storage/mozStorageStatementParams.cpp
new file mode 100644
index 0000000000..2d29e53a87
--- /dev/null
+++ b/storage/mozStorageStatementParams.cpp
@@ -0,0 +1,131 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozStorageStatementParams.h"
+
+#include "nsJSUtils.h"
+#include "nsString.h"
+
+#include "jsapi.h"
+
+#include "mozilla/ErrorResult.h"
+#include "mozilla/dom/MozStorageStatementParamsBinding.h"
+#include "mozStoragePrivateHelpers.h"
+#include "mozStorageStatement.h"
+
+namespace mozilla {
+namespace storage {
+
+////////////////////////////////////////////////////////////////////////////////
+//// StatementParams
+
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(StatementParams, mWindow)
+
+NS_INTERFACE_TABLE_HEAD(StatementParams)
+  NS_WRAPPERCACHE_INTERFACE_TABLE_ENTRY
+  NS_INTERFACE_TABLE(StatementParams, nsISupports)
+  NS_INTERFACE_TABLE_TO_MAP_SEGUE_CYCLE_COLLECTION(StatementParams)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(StatementParams)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(StatementParams)
+
+StatementParams::StatementParams(nsPIDOMWindowInner* aWindow,
+                                 Statement* aStatement)
+    : mWindow(aWindow), mStatement(aStatement), mParamCount(0) {
+  NS_ASSERTION(mStatement != nullptr, "mStatement is null");
+  (void)mStatement->GetParameterCount(&mParamCount);
+}
+
+JSObject* StatementParams::WrapObject(JSContext* aCx,
+                                      JS::Handle<JSObject*> aGivenProto) {
+  return dom::MozStorageStatementParams_Binding::Wrap(aCx, this, aGivenProto);
+}
+
+void StatementParams::NamedGetter(JSContext* aCx, const nsAString& aName,
+                                  bool& aFound,
+                                  JS::MutableHandle<JS::Value> aResult,
+                                  mozilla::ErrorResult& aRv) {
+  if (!mStatement) {
+    aRv.Throw(NS_ERROR_NOT_INITIALIZED);
+    return;
+  }
+
+  // Unfortunately there's no API that lets us return the parameter value.
+  aFound = false;
+}
+
+void StatementParams::NamedSetter(JSContext* aCx, const nsAString& aName,
+                                  JS::Handle<JS::Value> aValue,
+                                  mozilla::ErrorResult& aRv) {
+  if (!mStatement) {
+    aRv.Throw(NS_ERROR_NOT_INITIALIZED);
+    return;
+  }
+
+  NS_ConvertUTF16toUTF8 name(aName);
+
+  // Check to see if there's a parameter with this name.
+  nsCOMPtr<nsIVariant> variant(convertJSValToVariant(aCx, aValue));
+  if (!variant) {
+    aRv.Throw(NS_ERROR_UNEXPECTED);
+    return;
+  }
+
+  aRv = mStatement->BindByName(name, variant);
+}
+
+void StatementParams::GetSupportedNames(nsTArray<nsString>& aNames) {
+  if (!mStatement) {
+    return;
+  }
+
+  for (uint32_t i = 0; i < mParamCount; i++) {
+    // Get the name of our parameter.
+    nsAutoCString name;
+    nsresult rv = mStatement->GetParameterName(i, name);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return;
+    }
+
+    // But drop the first character, which is going to be a ':'.
+    name = Substring(name, 1);
+    aNames.AppendElement(NS_ConvertUTF8toUTF16(name));
+  }
+}
+
+void StatementParams::IndexedGetter(JSContext* aCx, uint32_t aIndex,
+                                    bool& aFound,
+                                    JS::MutableHandle<JS::Value> aResult,
+                                    mozilla::ErrorResult& aRv) {
+  if (!mStatement) {
+    aRv.Throw(NS_ERROR_NOT_INITIALIZED);
+    return;
+  }
+
+  // Unfortunately there's no API that lets us return the parameter value.
+  aFound = false;
+}
+
+void StatementParams::IndexedSetter(JSContext* aCx, uint32_t aIndex,
+                                    JS::Handle<JS::Value> aValue,
+                                    mozilla::ErrorResult& aRv) {
+  if (!mStatement) {
+    aRv.Throw(NS_ERROR_NOT_INITIALIZED);
+    return;
+  }
+
+  nsCOMPtr<nsIVariant> variant(convertJSValToVariant(aCx, aValue));
+  if (!variant) {
+    aRv.Throw(NS_ERROR_UNEXPECTED);
+    return;
+  }
+
+  aRv = mStatement->BindByIndex(aIndex, variant);
+}
+
+}  // namespace storage
+}  // namespace mozilla
diff --git a/storage/mozStorageStatementParams.h b/storage/mozStorageStatementParams.h
new file mode 100644
index 0000000000..6164f9854e
--- /dev/null
+++ b/storage/mozStorageStatementParams.h
@@ -0,0 +1,64 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef MOZSTORAGESTATEMENTPARAMS_H
+#define MOZSTORAGESTATEMENTPARAMS_H
+
+#include "mozilla/Attributes.h"
+#include "nsPIDOMWindow.h"
+#include "nsWrapperCache.h"
+
+namespace mozilla {
+class ErrorResult;
+
+namespace storage {
+
+class Statement;
+
+class StatementParams final : public nsISupports, public nsWrapperCache {
+ public:
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS(StatementParams)
+
+  explicit StatementParams(nsPIDOMWindowInner* aWindow, Statement* aStatement);
+
+  void NamedGetter(JSContext* aCx, const nsAString& aName, bool& aFound,
+                   JS::MutableHandle<JS::Value> aResult,
+                   mozilla::ErrorResult& aRv);
+
+  void NamedSetter(JSContext* aCx, const nsAString& aName,
+                   JS::Handle<JS::Value> aValue, mozilla::ErrorResult& aRv);
+
+  uint32_t Length() const { return mParamCount; }
+
+  void IndexedGetter(JSContext* aCx, uint32_t aIndex, bool& aFound,
+                     JS::MutableHandle<JS::Value> aResult,
+                     mozilla::ErrorResult& aRv);
+
+  void IndexedSetter(JSContext* aCx, uint32_t aIndex,
+                     JS::Handle<JS::Value> aValue, mozilla::ErrorResult& aRv);
+
+  void GetSupportedNames(nsTArray<nsString>& aNames);
+
+  JSObject* WrapObject(JSContext* aCx,
+                       JS::Handle<JSObject*> aGivenProto) override;
+
+  nsPIDOMWindowInner* GetParentObject() const { return mWindow; }
+
+ private:
+  ~StatementParams() {}
+
+  nsCOMPtr<nsPIDOMWindowInner> mWindow;
+  Statement* mStatement;
+  uint32_t mParamCount;
+
+  friend class StatementParamsHolder;
+};
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif /* MOZSTORAGESTATEMENTPARAMS_H */
diff --git a/storage/mozStorageStatementRow.cpp b/storage/mozStorageStatementRow.cpp
new file mode 100644
index 0000000000..7d203d7513
--- /dev/null
+++ b/storage/mozStorageStatementRow.cpp
@@ -0,0 +1,152 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsString.h"
+
+#include "mozilla/ErrorResult.h"
+#include "mozilla/dom/MozStorageStatementRowBinding.h"
+#include "mozStorageStatementRow.h"
+#include "mozStorageStatement.h"
+
+#include "jsapi.h"
+#include "js/Array.h"               // JS::NewArrayObject
+#include "js/PropertyAndElement.h"  // JS_DefineElement
+#include "js/Value.h"
+
+#include "xpc_make_class.h"
+
+namespace mozilla {
+namespace storage {
+
+////////////////////////////////////////////////////////////////////////////////
+//// StatementRow
+
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(StatementRow, mWindow)
+
+NS_INTERFACE_TABLE_HEAD(StatementRow)
+  NS_WRAPPERCACHE_INTERFACE_TABLE_ENTRY
+  NS_INTERFACE_TABLE(StatementRow, nsISupports)
+  NS_INTERFACE_TABLE_TO_MAP_SEGUE_CYCLE_COLLECTION(StatementRow)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(StatementRow)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(StatementRow)
+
+StatementRow::StatementRow(nsPIDOMWindowInner* aWindow, Statement* aStatement)
+    : mWindow(aWindow), mStatement(aStatement) {}
+
+JSObject* StatementRow::WrapObject(JSContext* aCx,
+                                   JS::Handle<JSObject*> aGivenProto) {
+  return dom::MozStorageStatementRow_Binding::Wrap(aCx, this, aGivenProto);
+}
+
+void StatementRow::NamedGetter(JSContext* aCx, const nsAString& aName,
+                               bool& aFound,
+                               JS::MutableHandle<JS::Value> aResult,
+                               mozilla::ErrorResult& aRv) {
+  if (!mStatement) {
+    aRv.Throw(NS_ERROR_NOT_INITIALIZED);
+    return;
+  }
+
+  nsCString name = NS_ConvertUTF16toUTF8(aName);
+
+  uint32_t idx;
+  {
+    nsresult rv = mStatement->GetColumnIndex(name, &idx);
+    if (NS_FAILED(rv)) {
+      // It's highly likely that the name doesn't exist, so let the JS engine
+      // check the prototype chain and throw if that doesn't have the property
+      // either.
+      aFound = false;
+      return;
+    }
+  }
+
+  int32_t type;
+  aRv = mStatement->GetTypeOfIndex(idx, &type);
+  if (aRv.Failed()) {
+    return;
+  }
+
+  switch (type) {
+    case mozIStorageValueArray::VALUE_TYPE_INTEGER:
+    case mozIStorageValueArray::VALUE_TYPE_FLOAT: {
+      double dval;
+      aRv = mStatement->GetDouble(idx, &dval);
+      if (aRv.Failed()) {
+        return;
+      }
+      aResult.set(::JS_NumberValue(dval));
+      break;
+    }
+    case mozIStorageValueArray::VALUE_TYPE_TEXT: {
+      uint32_t bytes;
+      const char16_t* sval = reinterpret_cast<const char16_t*>(
+          static_cast<mozIStorageStatement*>(mStatement)
+              ->AsSharedWString(idx, &bytes));
+      JSString* str =
+          ::JS_NewUCStringCopyN(aCx, sval, bytes / sizeof(char16_t));
+      if (!str) {
+        aRv.Throw(NS_ERROR_UNEXPECTED);
+        return;
+      }
+      aResult.setString(str);
+      break;
+    }
+    case mozIStorageValueArray::VALUE_TYPE_BLOB: {
+      uint32_t length;
+      const uint8_t* blob = static_cast<mozIStorageStatement*>(mStatement)
+                                ->AsSharedBlob(idx, &length);
+      JS::Rooted<JSObject*> obj(aCx, JS::NewArrayObject(aCx, length));
+      if (!obj) {
+        aRv.Throw(NS_ERROR_UNEXPECTED);
+        return;
+      }
+      aResult.setObject(*obj);
+
+      // Copy the blob over to the JS array.
+      for (uint32_t i = 0; i < length; i++) {
+        if (!::JS_DefineElement(aCx, obj, i, blob[i], JSPROP_ENUMERATE)) {
+          aRv.Throw(NS_ERROR_UNEXPECTED);
+          return;
+        }
+      }
+      break;
+    }
+    case mozIStorageValueArray::VALUE_TYPE_NULL:
+      aResult.setNull();
+      break;
+    default:
+      NS_ERROR("unknown column type returned, what's going on?");
+      break;
+  }
+  aFound = true;
+}
+
+void StatementRow::GetSupportedNames(nsTArray<nsString>& aNames) {
+  if (!mStatement) {
+    return;
+  }
+
+  uint32_t columnCount;
+  nsresult rv = mStatement->GetColumnCount(&columnCount);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return;
+  }
+
+  for (uint32_t i = 0; i < columnCount; i++) {
+    nsAutoCString name;
+    nsresult rv = mStatement->GetColumnName(i, name);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return;
+    }
+    aNames.AppendElement(NS_ConvertUTF8toUTF16(name));
+  }
+}
+
+}  // namespace storage
+}  // namespace mozilla
diff --git a/storage/mozStorageStatementRow.h b/storage/mozStorageStatementRow.h
new file mode 100644
index 0000000000..319645638d
--- /dev/null
+++ b/storage/mozStorageStatementRow.h
@@ -0,0 +1,50 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef MOZSTORAGESTATEMENTROW_H
+#define MOZSTORAGESTATEMENTROW_H
+
+#include "mozilla/Attributes.h"
+#include "nsPIDOMWindow.h"
+#include "nsWrapperCache.h"
+
+namespace mozilla {
+class ErrorResult;
+
+namespace storage {
+
+class Statement;
+
+class StatementRow final : public nsISupports, public nsWrapperCache {
+ public:
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS(StatementRow)
+
+  explicit StatementRow(nsPIDOMWindowInner* aWindow, Statement* aStatement);
+
+  void NamedGetter(JSContext* aCx, const nsAString& aName, bool& aFound,
+                   JS::MutableHandle<JS::Value> aResult,
+                   mozilla::ErrorResult& aRv);
+  void GetSupportedNames(nsTArray<nsString>& aNames);
+
+  JSObject* WrapObject(JSContext* aCx,
+                       JS::Handle<JSObject*> aGivenProto) override;
+
+  nsPIDOMWindowInner* GetParentObject() const { return mWindow; }
+
+ private:
+  ~StatementRow() {}
+
+  nsCOMPtr<nsPIDOMWindowInner> mWindow;
+  Statement* mStatement;
+
+  friend class StatementRowHolder;
+};
+
+}  // namespace storage
+}  // namespace mozilla
+
+#endif /* MOZSTORAGESTATEMENTROW_H */
diff --git a/storage/rust/Cargo.toml b/storage/rust/Cargo.toml
new file mode 100644
index 0000000000..bf65f94146
--- /dev/null
+++ b/storage/rust/Cargo.toml
@@ -0,0 +1,14 @@
+[package]
+name = "storage"
+description = "Rust bindings for mozStorage."
+version = "0.1.0"
+authors = ["Lina Cambridge <lina@yakshaving.ninja>"]
+edition = "2018"
+license = "MPL-2.0"
+
+[dependencies]
+libc = "0.2"
+nserror = { path = "../../xpcom/rust/nserror" }
+nsstring = { path = "../../xpcom/rust/nsstring" }
+storage_variant = { path = "../variant" }
+xpcom = { path = "../../xpcom/rust/xpcom" }
diff --git a/storage/rust/src/lib.rs b/storage/rust/src/lib.rs
new file mode 100644
index 0000000000..91984bcafc
--- /dev/null
+++ b/storage/rust/src/lib.rs
@@ -0,0 +1,533 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//! A Rust wrapper for mozStorage.
+//!
+//! mozStorage wraps the SQLite C API with support for XPCOM data structures,
+//! asynchronous statement execution, cleanup on shutdown, and connection
+//! cloning that propagates attached databases, pragmas, functions, and
+//! temporary entities. It also collects timing and memory usage stats for
+//! telemetry, and supports detailed statement logging. Additionally, mozStorage
+//! makes it possible to use the same connection handle from JS and native
+//! (C++ and Rust) code.
+//!
+//! Most mozStorage objects, like connections, statements, result rows,
+//! and variants, are thread-safe. Each connection manages a background
+//! thread that can be used to execute statements asynchronously, without
+//! blocking the main thread.
+//!
+//! This crate provides a thin wrapper to make mozStorage easier to use
+//! from Rust. It only wraps the synchronous API, so you can either manage
+//! the entire connection from a background thread, or use the `moz_task`
+//! crate to dispatch tasks to the connection's async thread. Executing
+//! synchronous statements on the main thread is not supported, and will
+//! assert in debug builds.
+
+#![allow(non_snake_case)]
+
+use std::{borrow::Cow, convert::TryFrom, error, fmt, ops::Deref, result};
+
+use nserror::{nsresult, NS_ERROR_NO_INTERFACE, NS_ERROR_UNEXPECTED};
+use nsstring::nsCString;
+use storage_variant::VariantType;
+use xpcom::{
+    getter_addrefs,
+    interfaces::{
+        mozIStorageAsyncConnection, mozIStorageConnection, mozIStorageStatement, nsIEventTarget,
+        nsIThread,
+    },
+    RefPtr, XpCom,
+};
+
+const SQLITE_OK: i32 = 0;
+
+pub type Result<T> = result::Result<T, Error>;
+
+/// `Conn` wraps a `mozIStorageConnection`.
+#[derive(Clone)]
+pub struct Conn {
+    handle: RefPtr<mozIStorageConnection>,
+}
+
+// This is safe as long as our `mozIStorageConnection` is an instance of
+// `mozilla::storage::Connection`, which is atomically reference counted.
+unsafe impl Send for Conn {}
+unsafe impl Sync for Conn {}
+
+impl Conn {
+    /// Wraps a `mozIStorageConnection` in a `Conn`.
+    #[inline]
+    pub fn wrap(connection: RefPtr<mozIStorageConnection>) -> Conn {
+        Conn { handle: connection }
+    }
+
+    /// Returns the wrapped `mozIStorageConnection`.
+    #[inline]
+    pub fn connection(&self) -> &mozIStorageConnection {
+        &self.handle
+    }
+
+    /// Returns the maximum number of bound parameters for statements executed
+    /// on this connection.
+    pub fn variable_limit(&self) -> Result<usize> {
+        let mut limit = 0i32;
+        let rv = unsafe { self.handle.GetVariableLimit(&mut limit) };
+        if rv.failed() {
+            return Err(Error::Limit);
+        }
+        usize::try_from(limit).map_err(|_| Error::Limit)
+    }
+
+    /// Returns the async thread for this connection. This can be used
+    /// with `moz_task` to run synchronous statements on the storage
+    /// thread, without blocking the main thread.
+    pub fn thread(&self) -> Result<RefPtr<nsIThread>> {
+        let target = self.handle.get_interface::<nsIEventTarget>();
+        target
+            .and_then(|t| t.query_interface::<nsIThread>())
+            .ok_or(Error::NoThread)
+    }
+
+    /// Prepares a SQL statement. `query` should only contain one SQL statement.
+    /// If `query` contains multiple statements, only the first will be prepared,
+    /// and the rest will be ignored.
+    pub fn prepare<Q: AsRef<str>>(&self, query: Q) -> Result<Statement> {
+        let statement = self.call_and_wrap_error(DatabaseOp::Prepare, || {
+            getter_addrefs(|p| unsafe {
+                self.handle
+                    .CreateStatement(&*nsCString::from(query.as_ref()), p)
+            })
+        })?;
+        Ok(Statement {
+            conn: self,
+            handle: statement,
+        })
+    }
+
+    /// Executes a SQL statement. `query` may contain one or more
+    /// semicolon-separated SQL statements.
+    pub fn exec<Q: AsRef<str>>(&self, query: Q) -> Result<()> {
+        self.call_and_wrap_error(DatabaseOp::Exec, || {
+            unsafe {
+                self.handle
+                    .ExecuteSimpleSQL(&*nsCString::from(query.as_ref()))
+            }
+            .to_result()
+        })
+    }
+
+    /// Opens a transaction with the default transaction behavior for this
+    /// connection. The transaction should be committed when done. Uncommitted
+    /// `Transaction`s will automatically roll back when they go out of scope.
+    pub fn transaction(&mut self) -> Result<Transaction> {
+        let behavior = self.get_default_transaction_behavior();
+        Transaction::new(self, behavior)
+    }
+
+    /// Indicates if a transaction is currently open on this connection.
+    /// Attempting to open a new transaction when one is already in progress
+    /// will fail with a "cannot start a transaction within a transaction"
+    /// error.
+    ///
+    /// Note that this is `true` even if the transaction was started by another
+    /// caller, like `Sqlite.sys.mjs` or `mozStorageTransaction` from C++. See the
+    /// explanation above `mozIStorageConnection.transactionInProgress` for why
+    /// this matters.
+    pub fn transaction_in_progress(&self) -> Result<bool> {
+        let mut in_progress = false;
+        unsafe { self.handle.GetTransactionInProgress(&mut in_progress) }.to_result()?;
+        Ok(in_progress)
+    }
+
+    /// Opens a transaction with the requested behavior.
+    pub fn transaction_with_behavior(
+        &mut self,
+        behavior: TransactionBehavior,
+    ) -> Result<Transaction> {
+        Transaction::new(self, behavior)
+    }
+
+    fn get_default_transaction_behavior(&self) -> TransactionBehavior {
+        let mut typ = 0i32;
+        let rv = unsafe { self.handle.GetDefaultTransactionType(&mut typ) };
+        if rv.failed() {
+            return TransactionBehavior::Deferred;
+        }
+        match typ {
+            mozIStorageAsyncConnection::TRANSACTION_IMMEDIATE => TransactionBehavior::Immediate,
+            mozIStorageAsyncConnection::TRANSACTION_EXCLUSIVE => TransactionBehavior::Exclusive,
+            _ => TransactionBehavior::Deferred,
+        }
+    }
+
+    /// Invokes a storage operation and returns the last SQLite error if the
+    /// operation fails. This lets `Conn::{prepare, exec}` and
+    /// `Statement::{step, execute}` return more detailed errors, as the
+    /// `nsresult` codes that mozStorage uses are often too generic. For
+    /// example, `NS_ERROR_FAILURE` might be anything from a SQL syntax error
+    /// to an invalid column name in a trigger.
+    ///
+    /// Note that the last error may not be accurate if the underlying
+    /// `mozIStorageConnection` is used concurrently from multiple threads.
+    /// Multithreaded callers that share a connection should serialize their
+    /// uses.
+    fn call_and_wrap_error<T>(
+        &self,
+        op: DatabaseOp,
+        func: impl FnOnce() -> result::Result<T, nsresult>,
+    ) -> Result<T> {
+        func().or_else(|rv| -> Result<T> {
+            let mut code = 0i32;
+            unsafe { self.handle.GetLastError(&mut code) }.to_result()?;
+            Err(if code != SQLITE_OK {
+                let mut message = nsCString::new();
+                unsafe { self.handle.GetLastErrorString(&mut *message) }.to_result()?;
+                Error::Database {
+                    rv,
+                    op,
+                    code,
+                    message,
+                }
+            } else {
+                rv.into()
+            })
+        })
+    }
+}
+
+pub enum TransactionBehavior {
+    Deferred,
+    Immediate,
+    Exclusive,
+}
+
+pub struct Transaction<'c> {
+    conn: &'c mut Conn,
+    active: bool,
+}
+
+impl<'c> Transaction<'c> {
+    /// Opens a transaction on `conn` with the given `behavior`.
+    fn new(conn: &'c mut Conn, behavior: TransactionBehavior) -> Result<Transaction<'c>> {
+        conn.exec(match behavior {
+            TransactionBehavior::Deferred => "BEGIN DEFERRED",
+            TransactionBehavior::Immediate => "BEGIN IMMEDIATE",
+            TransactionBehavior::Exclusive => "BEGIN EXCLUSIVE",
+        })?;
+        Ok(Transaction { conn, active: true })
+    }
+
+    /// Commits the transaction.
+    pub fn commit(mut self) -> Result<()> {
+        if self.active {
+            self.conn.exec("COMMIT")?;
+            self.active = false;
+        }
+        Ok(())
+    }
+
+    /// Rolls the transaction back.
+    pub fn rollback(mut self) -> Result<()> {
+        self.abort()
+    }
+
+    fn abort(&mut self) -> Result<()> {
+        if self.active {
+            self.conn.exec("ROLLBACK")?;
+            self.active = false;
+        }
+        Ok(())
+    }
+}
+
+impl<'c> Deref for Transaction<'c> {
+    type Target = Conn;
+
+    fn deref(&self) -> &Conn {
+        self.conn
+    }
+}
+
+impl<'c> Drop for Transaction<'c> {
+    fn drop(&mut self) {
+        let _ = self.abort();
+    }
+}
+
+pub struct Statement<'c> {
+    conn: &'c Conn,
+    handle: RefPtr<mozIStorageStatement>,
+}
+
+impl<'c> Statement<'c> {
+    /// Binds a parameter at the given `index` to the prepared statement.
+    /// `value` is any type that can be converted into a `Variant`.
+    pub fn bind_by_index<V: VariantType>(&mut self, index: u32, value: V) -> Result<()> {
+        let variant = value.into_variant();
+        unsafe { self.handle.BindByIndex(index as u32, variant.coerce()) }
+            .to_result()
+            .map_err(|rv| Error::BindByIndex {
+                rv,
+                data_type: V::type_name(),
+                index,
+            })
+    }
+
+    /// Binds a parameter with the given `name` to the prepared statement.
+    pub fn bind_by_name<N: AsRef<str>, V: VariantType>(&mut self, name: N, value: V) -> Result<()> {
+        let name = name.as_ref();
+        let variant = value.into_variant();
+        unsafe {
+            self.handle
+                .BindByName(&*nsCString::from(name), variant.coerce())
+        }
+        .to_result()
+        .map_err(|rv| Error::BindByName {
+            rv,
+            data_type: V::type_name(),
+            name: name.into(),
+        })
+    }
+
+    /// Executes the statement and returns the next row of data.
+    pub fn step<'s>(&'s mut self) -> Result<Option<Step<'c, 's>>> {
+        let has_more = self.conn.call_and_wrap_error(DatabaseOp::Step, || {
+            let mut has_more = false;
+            unsafe { self.handle.ExecuteStep(&mut has_more) }.to_result()?;
+            Ok(has_more)
+        })?;
+        Ok(if has_more { Some(Step(self)) } else { None })
+    }
+
+    /// Executes the statement once, discards any data, and resets the
+    /// statement.
+    pub fn execute(&mut self) -> Result<()> {
+        self.conn.call_and_wrap_error(DatabaseOp::Execute, || {
+            unsafe { self.handle.Execute() }.to_result()
+        })
+    }
+
+    /// Resets the prepared statement so that it's ready to be executed
+    /// again, and clears any bound parameters.
+    pub fn reset(&mut self) -> Result<()> {
+        unsafe { self.handle.Reset() }.to_result()?;
+        Ok(())
+    }
+
+    fn get_column_index(&self, name: &str) -> Result<u32> {
+        let mut index = 0u32;
+        let rv = unsafe {
+            self.handle
+                .GetColumnIndex(&*nsCString::from(name), &mut index)
+        };
+        if rv.succeeded() {
+            Ok(index)
+        } else {
+            Err(Error::InvalidColumn {
+                rv,
+                name: name.into(),
+            })
+        }
+    }
+
+    fn get_column_value<T: VariantType>(&self, index: u32) -> result::Result<T, nsresult> {
+        let variant = getter_addrefs(|p| unsafe { self.handle.GetVariant(index, p) })?;
+        let value = T::from_variant(variant.coerce())?;
+        Ok(value)
+    }
+}
+
+impl<'c> Drop for Statement<'c> {
+    fn drop(&mut self) {
+        unsafe { self.handle.Finalize() };
+    }
+}
+
+/// A step is the next row in the result set for a statement.
+pub struct Step<'c, 's>(&'s mut Statement<'c>);
+
+impl<'c, 's> Step<'c, 's> {
+    /// Returns the value of the column at `index` for the current row.
+    pub fn get_by_index<T: VariantType>(&self, index: u32) -> Result<T> {
+        self.0
+            .get_column_value(index)
+            .map_err(|rv| Error::GetByIndex {
+                rv,
+                data_type: T::type_name(),
+                index,
+            })
+    }
+
+    /// A convenience wrapper that returns the default value for the column
+    /// at `index` if `NULL`.
+    pub fn get_by_index_or_default<T: VariantType + Default>(&self, index: u32) -> T {
+        self.get_by_index(index).unwrap_or_default()
+    }
+
+    /// Returns the value of the column specified by `name` for the current row.
+    pub fn get_by_name<N: AsRef<str>, T: VariantType>(&self, name: N) -> Result<T> {
+        let name = name.as_ref();
+        let index = self.0.get_column_index(name)?;
+        self.0
+            .get_column_value(index)
+            .map_err(|rv| Error::GetByName {
+                rv,
+                data_type: T::type_name(),
+                name: name.into(),
+            })
+    }
+
+    /// Returns the default value for the column with the given `name`, or the
+    /// default if the column is `NULL`.
+    pub fn get_by_name_or_default<N: AsRef<str>, T: VariantType + Default>(&self, name: N) -> T {
+        self.get_by_name(name).unwrap_or_default()
+    }
+}
+
+/// A database operation, included for better context in error messages.
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub enum DatabaseOp {
+    Exec,
+    Prepare,
+    Step,
+    Execute,
+}
+
+impl DatabaseOp {
+    /// Returns a description of the operation to include in an error message.
+    pub fn what(&self) -> &'static str {
+        match self {
+            DatabaseOp::Exec => "execute SQL string",
+            DatabaseOp::Prepare => "prepare statement",
+            DatabaseOp::Step => "step statement",
+            DatabaseOp::Execute => "execute statement",
+        }
+    }
+}
+
+/// Storage errors.
+#[derive(Debug)]
+pub enum Error {
+    /// A connection doesn't have a usable async thread. The connection might be
+    /// closed, or the thread manager may have shut down.
+    NoThread,
+
+    /// Failed to get a limit for a database connection.
+    Limit,
+
+    /// A database operation failed. The error includes a SQLite result code,
+    /// and an explanation string.
+    Database {
+        rv: nsresult,
+        op: DatabaseOp,
+        code: i32,
+        message: nsCString,
+    },
+
+    /// A parameter with the given data type couldn't be bound at this index,
+    /// likely because the index is out of range.
+    BindByIndex {
+        rv: nsresult,
+        data_type: Cow<'static, str>,
+        index: u32,
+    },
+
+    /// A parameter with the given type couldn't be bound to this name, likely
+    /// because the statement doesn't have a matching `:`-prefixed parameter
+    /// with the name.
+    BindByName {
+        rv: nsresult,
+        data_type: Cow<'static, str>,
+        name: String,
+    },
+
+    /// A column with this name doesn't exist.
+    InvalidColumn { rv: nsresult, name: String },
+
+    /// A value of the given type couldn't be accessed at this index. This is
+    /// the error returned when a type conversion fails; for example, requesting
+    /// an `nsString` instead of an `Option<nsString>` when the column is `NULL`.
+    GetByIndex {
+        rv: nsresult,
+        data_type: Cow<'static, str>,
+        index: u32,
+    },
+
+    /// A value of the given type couldn't be accessed for the column with
+    /// this name.
+    GetByName {
+        rv: nsresult,
+        data_type: Cow<'static, str>,
+        name: String,
+    },
+
+    /// A storage operation failed for other reasons.
+    Other(nsresult),
+}
+
+impl error::Error for Error {
+    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
+        None
+    }
+}
+
+impl From<nsresult> for Error {
+    fn from(rv: nsresult) -> Error {
+        Error::Other(rv)
+    }
+}
+
+impl From<Error> for nsresult {
+    fn from(err: Error) -> nsresult {
+        match err {
+            Error::NoThread => NS_ERROR_NO_INTERFACE,
+            Error::Limit => NS_ERROR_UNEXPECTED,
+            Error::Database { rv, .. }
+            | Error::BindByIndex { rv, .. }
+            | Error::BindByName { rv, .. }
+            | Error::InvalidColumn { rv, .. }
+            | Error::GetByIndex { rv, .. }
+            | Error::GetByName { rv, .. }
+            | Error::Other(rv) => rv,
+        }
+    }
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            Error::NoThread => f.write_str("Async thread unavailable for storage connection"),
+            Error::Limit => f.write_str("Failed to get limit for storage connection"),
+            Error::Database {
+                op, code, message, ..
+            } => {
+                if message.is_empty() {
+                    write!(f, "Failed to {} with code {}", op.what(), code)
+                } else {
+                    write!(
+                        f,
+                        "Failed to {} with code {} ({})",
+                        op.what(),
+                        code,
+                        message
+                    )
+                }
+            }
+            Error::BindByIndex {
+                data_type, index, ..
+            } => write!(f, "Can't bind {} at {}", data_type, index),
+            Error::BindByName {
+                data_type, name, ..
+            } => write!(f, "Can't bind {} to named parameter {}", data_type, name),
+            Error::InvalidColumn { name, .. } => write!(f, "Column {} doesn't exist", name),
+            Error::GetByIndex {
+                data_type, index, ..
+            } => write!(f, "Can't get {} at {}", data_type, index),
+            Error::GetByName {
+                data_type, name, ..
+            } => write!(f, "Can't get {} for column {}", data_type, name),
+            Error::Other(rv) => write!(f, "Storage operation failed with {}", rv.error_name()),
+        }
+    }
+}
diff --git a/storage/storage.h b/storage/storage.h
new file mode 100644
index 0000000000..6c47755d88
--- /dev/null
+++ b/storage/storage.h
@@ -0,0 +1,24 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_storage_h_
+#define mozilla_storage_h_
+
+////////////////////////////////////////////////////////////////////////////////
+//// Public Interfaces
+
+#include "mozStorageCID.h"
+#include "mozIStorageStatement.h"
+#include "mozIStorageBindingParams.h"
+
+////////////////////////////////////////////////////////////////////////////////
+//// Native Language Helpers
+
+#include "mozStorageHelper.h"
+#include "mozilla/storage/StatementCache.h"
+#include "mozilla/storage/Variant.h"
+
+#endif  // mozilla_storage_h_
diff --git a/storage/style.txt b/storage/style.txt
new file mode 100644
index 0000000000..03652e6066
--- /dev/null
+++ b/storage/style.txt
@@ -0,0 +1,141 @@
+Storage Module Style Guidelines
+
+These guidelines should be followed for all new code in this module.  Reviewers
+will be enforcing them, so please obey them!
+
+* All code should be contained within the namespace mozilla::storage at a
+  minimum.  The use of namespaces is strongly encouraged.
+
+* All functions being called in the global namespace should be prefixed with
+  "::" to indicate that they are in the global namespace.
+
+* The indentation level to use in source code is two spaces.  No tabs, please!
+
+* All files should have the following emacs and vim mode lines:
+  -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+  vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+
+* All functions that are not XPCOM should start with a lowercase letter.
+
+* Function arguments that are not out parameters should be prefixed with a (for
+  pArameter), and use CamelCase.
+
+* Function arguments that are out parameters should be prefixed with an
+  underscore and have a descriptive name.
+
+* Function declarations should include javadoc style comments.
+
+* Javadoc @param tags should have the parameter description start on a new line
+  aligned with the variable name.  See the example below.
+
+* Javadoc @return (note: non-plural) continuation lines should be lined up with
+  the initial comment.  See the example below.
+
+* Javadoc @throws, like @param, should have the exception type on the same line
+  as the @throws and the description on a new line indented to line up with
+  the type of the exception.
+
+* For function implementations, each argument should be on its own line.
+
+* All variables should use camelCase.
+
+* The use of bool is encouraged whenever the variable does not have the
+  potential to go through xpconnect.
+
+* For pointer variable types, include a space after the type before the asterisk
+  and no space between the asterisk and variable name.
+
+* If any part of an if-else block requires braces, all blocks need braces.
+
+* Every else should be on a newline after a brace.
+
+* Bracing should start on the line after a function and class definition.  This
+  goes for JavaScript code as well as C++ code.
+
+* If a return value is not going to be checked, the return value should be
+  explicitly casted to void (C style cast).
+
+
+BIG EXAMPLE:
+
+*** Header ***
+
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_storage_FILENAME_h_
+#define mozilla_storage_FILENAME_h_
+
+namespace mozilla {
+namespace storage {
+
+class Foo : public Bar
+          , public Baz
+{
+public:
+  /**
+   * Brief function summary.
+   *
+   * @param aArg1
+   *        Description description description description description etc etc
+   *        next line of description.
+   * @param aArg2
+   *        Description description description.
+   * @return Description description description description description etc etc
+   *         next line of description.
+   *
+   * @throws NS_ERROR_FAILURE
+   *         Okay, so this is for JavaScript code, but you probably get the
+   *         idea.
+   */
+  int chew(int aArg1, int aArg2);
+};
+
+} // storage
+} // mozilla
+
+#endif // mozilla_storage_FILENAME_h_
+
+
+*** Implementation ***
+
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+NS_IMPL_ISUPPORTS(
+  Foo
+, IBar
+, IBaz
+)
+
+Foo::Foo(
+  LongArgumentLineThatWouldOtherwiseOverflow *aArgument1
+)
+: mField1(0)
+, mField2(0)
+{
+  someMethodWithLotsOfParamsOrJustLongParameters(
+    mLongFieldNameThatIsJustified,
+    mMaybeThisOneIsLessJustifiedButBoyIsItLong,
+    15
+  );
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Separate sections of the file like this
+
+int
+Foo::chew(int aArg1, int aArg2)
+{
+  (void)functionReturningAnIgnoredValue();
+
+  ::functionFromGlobalNamespaceWithVoidReturnValue();
+
+  return 0;
+}
diff --git a/storage/test/gtest/moz.build b/storage/test/gtest/moz.build
new file mode 100644
index 0000000000..db15c440f8
--- /dev/null
+++ b/storage/test/gtest/moz.build
@@ -0,0 +1,40 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+UNIFIED_SOURCES += [
+    "storage_test_harness.cpp",
+    "test_AsXXX_helpers.cpp",
+    "test_async_callbacks_with_spun_event_loops.cpp",
+    "test_async_thread_naming.cpp",
+    "test_asyncStatementExecution_transaction.cpp",
+    "test_binding_params.cpp",
+    "test_file_perms.cpp",
+    "test_interruptSynchronousConnection.cpp",
+    "test_mutex.cpp",
+    "test_spinningSynchronousClose.cpp",
+    "test_statement_scoper.cpp",
+    "test_StatementCache.cpp",
+    "test_transaction_helper.cpp",
+    "test_true_async.cpp",
+    "test_unlock_notify.cpp",
+]
+
+if (
+    CONFIG["MOZ_DEBUG"]
+    and CONFIG["OS_ARCH"] not in ("WINNT")
+    and CONFIG["OS_TARGET"] != "Android"
+):
+    # FIXME bug 523392: test_deadlock_detector doesn't like Windows
+    # Bug 1054249: Doesn't work on Android
+    UNIFIED_SOURCES += [
+        "test_deadlock_detector.cpp",
+    ]
+
+LOCAL_INCLUDES += [
+    "../..",
+]
+
+FINAL_LIBRARY = "xul-gtest"
diff --git a/storage/test/gtest/storage_test_harness.cpp b/storage/test/gtest/storage_test_harness.cpp
new file mode 100644
index 0000000000..29caa1792b
--- /dev/null
+++ b/storage/test/gtest/storage_test_harness.cpp
@@ -0,0 +1,244 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef storage_test_harness_
+#define storage_test_harness_
+
+#include "storage_test_harness.h"
+
+already_AddRefed<mozIStorageService> getService() {
+  nsCOMPtr<mozIStorageService> ss =
+      do_CreateInstance("@mozilla.org/storage/service;1");
+  do_check_true(ss);
+  return ss.forget();
+}
+
+already_AddRefed<mozIStorageConnection> getMemoryDatabase() {
+  nsCOMPtr<mozIStorageService> ss = getService();
+  nsCOMPtr<mozIStorageConnection> conn;
+  nsresult rv = ss->OpenSpecialDatabase(
+      kMozStorageMemoryStorageKey, VoidCString(),
+      mozIStorageService::CONNECTION_DEFAULT, getter_AddRefs(conn));
+  do_check_success(rv);
+  return conn.forget();
+}
+
+already_AddRefed<mozIStorageConnection> getDatabase(nsIFile* aDBFile,
+                                                    uint32_t aConnectionFlags) {
+  nsCOMPtr<nsIFile> dbFile;
+  nsresult rv;
+  if (!aDBFile) {
+    MOZ_RELEASE_ASSERT(NS_IsMainThread(), "Can't get tmp dir off mainthread.");
+    (void)NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR,
+                                 getter_AddRefs(dbFile));
+    NS_ASSERTION(dbFile, "The directory doesn't exists?!");
+
+    rv = dbFile->Append(u"storage_test_db.sqlite"_ns);
+    do_check_success(rv);
+  } else {
+    dbFile = aDBFile;
+  }
+
+  nsCOMPtr<mozIStorageService> ss = getService();
+  nsCOMPtr<mozIStorageConnection> conn;
+  rv = ss->OpenDatabase(dbFile, aConnectionFlags, getter_AddRefs(conn));
+  do_check_success(rv);
+  return conn.forget();
+}
+
+NS_IMPL_ISUPPORTS(AsyncStatementSpinner, mozIStorageStatementCallback,
+                  mozIStorageCompletionCallback)
+
+AsyncStatementSpinner::AsyncStatementSpinner()
+    : completionReason(0), mCompleted(false) {}
+
+NS_IMETHODIMP
+AsyncStatementSpinner::HandleResult(mozIStorageResultSet* aResultSet) {
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+AsyncStatementSpinner::HandleError(mozIStorageError* aError) {
+  int32_t result;
+  nsresult rv = aError->GetResult(&result);
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsAutoCString message;
+  rv = aError->GetMessage(message);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsAutoCString warnMsg;
+  warnMsg.AppendLiteral(
+      "An error occurred while executing an async statement: ");
+  warnMsg.AppendInt(result);
+  warnMsg.Append(' ');
+  warnMsg.Append(message);
+  NS_WARNING(warnMsg.get());
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+AsyncStatementSpinner::HandleCompletion(uint16_t aReason) {
+  completionReason = aReason;
+  mCompleted = true;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+AsyncStatementSpinner::Complete(nsresult, nsISupports*) {
+  mCompleted = true;
+  return NS_OK;
+}
+
+void AsyncStatementSpinner::SpinUntilCompleted() {
+  nsCOMPtr<nsIThread> thread(::do_GetCurrentThread());
+  nsresult rv = NS_OK;
+  bool processed = true;
+  while (!mCompleted && NS_SUCCEEDED(rv)) {
+    rv = thread->ProcessNextEvent(true, &processed);
+  }
+}
+
+#define NS_DECL_ASYNCSTATEMENTSPINNER \
+  NS_IMETHOD HandleResult(mozIStorageResultSet* aResultSet) override;
+
+NS_IMPL_ISUPPORTS(AsyncCompletionSpinner, mozIStorageCompletionCallback)
+
+AsyncCompletionSpinner::AsyncCompletionSpinner()
+    : mCompletionReason(NS_OK), mCompleted(false) {}
+
+NS_IMETHODIMP
+AsyncCompletionSpinner::Complete(nsresult reason, nsISupports* value) {
+  mCompleted = true;
+  mCompletionReason = reason;
+  mCompletionValue = value;
+  return NS_OK;
+}
+
+void AsyncCompletionSpinner::SpinUntilCompleted() {
+  nsCOMPtr<nsIThread> thread(::do_GetCurrentThread());
+  nsresult rv = NS_OK;
+  bool processed = true;
+  while (!mCompleted && NS_SUCCEEDED(rv)) {
+    rv = thread->ProcessNextEvent(true, &processed);
+  }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Async Helpers
+
+/**
+ * Execute an async statement, blocking the main thread until we get the
+ * callback completion notification.
+ */
+void blocking_async_execute(mozIStorageBaseStatement* stmt) {
+  RefPtr<AsyncStatementSpinner> spinner(new AsyncStatementSpinner());
+
+  nsCOMPtr<mozIStoragePendingStatement> pendy;
+  (void)stmt->ExecuteAsync(spinner, getter_AddRefs(pendy));
+  spinner->SpinUntilCompleted();
+}
+
+/**
+ * Invoke AsyncClose on the given connection, blocking the main thread until we
+ * get the completion notification.
+ */
+void blocking_async_close(mozIStorageConnection* db) {
+  RefPtr<AsyncStatementSpinner> spinner(new AsyncStatementSpinner());
+
+  db->AsyncClose(spinner);
+  spinner->SpinUntilCompleted();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Mutex Watching
+
+/**
+ * Verify that mozIStorageAsyncStatement's life-cycle never triggers a mutex on
+ * the caller (generally main) thread.  We do this by decorating the sqlite
+ * mutex logic with our own code that checks what thread it is being invoked on
+ * and sets a flag if it is invoked on the main thread.  We are able to easily
+ * decorate the SQLite mutex logic because SQLite allows us to retrieve the
+ * current function pointers being used and then provide a new set.
+ */
+
+sqlite3_mutex_methods orig_mutex_methods;
+sqlite3_mutex_methods wrapped_mutex_methods;
+
+bool mutex_used_on_watched_thread = false;
+PRThread* watched_thread = nullptr;
+/**
+ * Ugly hack to let us figure out what a connection's async thread is.  If we
+ * were MOZILLA_INTERNAL_API and linked as such we could just include
+ * mozStorageConnection.h and just ask Connection directly.  But that turns out
+ * poorly.
+ *
+ * When the thread a mutex is invoked on isn't watched_thread we save it to this
+ * variable.
+ */
+nsIThread* last_non_watched_thread = nullptr;
+
+/**
+ * Set a flag if the mutex is used on the thread we are watching, but always
+ * call the real mutex function.
+ */
+extern "C" void wrapped_MutexEnter(sqlite3_mutex* mutex) {
+  if (PR_GetCurrentThread() == watched_thread) {
+    mutex_used_on_watched_thread = true;
+  } else {
+    last_non_watched_thread = NS_GetCurrentThread();
+  }
+  orig_mutex_methods.xMutexEnter(mutex);
+}
+
+extern "C" int wrapped_MutexTry(sqlite3_mutex* mutex) {
+  if (::PR_GetCurrentThread() == watched_thread) {
+    mutex_used_on_watched_thread = true;
+  }
+  return orig_mutex_methods.xMutexTry(mutex);
+}
+
+/**
+ * Call to clear the watch state and to set the watching against this thread.
+ *
+ * Check |mutex_used_on_watched_thread| to see if the mutex has fired since
+ * this method was last called.  Since we're talking about the current thread,
+ * there are no race issues to be concerned about
+ */
+void watch_for_mutex_use_on_this_thread() {
+  watched_thread = ::PR_GetCurrentThread();
+  mutex_used_on_watched_thread = false;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Async Helpers
+
+/**
+ * A horrible hack to figure out what the connection's async thread is.  By
+ * creating a statement and async dispatching we can tell from the mutex who
+ * is the async thread, PRThread style.  Then we map that to an nsIThread.
+ */
+already_AddRefed<nsIThread> get_conn_async_thread(mozIStorageConnection* db) {
+  // Make sure we are tracking the current thread as the watched thread
+  watch_for_mutex_use_on_this_thread();
+
+  // - statement with nothing to bind
+  nsCOMPtr<mozIStorageAsyncStatement> stmt;
+  db->CreateAsyncStatement("SELECT 1"_ns, getter_AddRefs(stmt));
+  blocking_async_execute(stmt);
+  stmt->Finalize();
+
+  nsCOMPtr<nsIThread> asyncThread = last_non_watched_thread;
+
+  // Additionally, check that the thread we get as the background thread is the
+  // same one as the one we report from getInterface.
+  nsCOMPtr<nsIEventTarget> target = do_GetInterface(db);
+  nsCOMPtr<nsIThread> allegedAsyncThread = do_QueryInterface(target);
+  do_check_eq(allegedAsyncThread, asyncThread);
+  return asyncThread.forget();
+}
+
+#endif  // storage_test_harness_h__
diff --git a/storage/test/gtest/storage_test_harness.h b/storage/test/gtest/storage_test_harness.h
new file mode 100644
index 0000000000..6f29dc43ad
--- /dev/null
+++ b/storage/test/gtest/storage_test_harness.h
@@ -0,0 +1,223 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef storage_test_harness_h__
+#define storage_test_harness_h__
+
+#include "gtest/gtest.h"
+
+#include "prthread.h"
+#include "nsAppDirectoryServiceDefs.h"
+#include "nsComponentManagerUtils.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsDirectoryServiceUtils.h"
+#include "nsServiceManagerUtils.h"
+#include "nsIThread.h"
+#include "nsThreadUtils.h"
+#include "mozilla/ReentrantMonitor.h"
+
+#include "mozIStorageService.h"
+#include "mozIStorageConnection.h"
+#include "mozIStorageStatementCallback.h"
+#include "mozIStorageCompletionCallback.h"
+#include "mozIStorageBindingParamsArray.h"
+#include "mozIStorageBindingParams.h"
+#include "mozIStorageAsyncStatement.h"
+#include "mozIStorageStatement.h"
+#include "mozIStoragePendingStatement.h"
+#include "mozIStorageError.h"
+#include "nsIInterfaceRequestorUtils.h"
+#include "nsIEventTarget.h"
+
+#include "sqlite3.h"
+
+#define do_check_true(aCondition) EXPECT_TRUE(aCondition)
+
+#define do_check_false(aCondition) EXPECT_FALSE(aCondition)
+
+#define do_check_success(aResult) do_check_true(NS_SUCCEEDED(aResult))
+
+#define do_check_eq(aExpected, aActual) do_check_true(aExpected == aActual)
+
+#define do_check_ok(aInvoc) do_check_true((aInvoc) == SQLITE_OK)
+
+already_AddRefed<mozIStorageService> getService();
+
+already_AddRefed<mozIStorageConnection> getMemoryDatabase();
+
+already_AddRefed<mozIStorageConnection> getDatabase(
+    nsIFile* aDBFile = nullptr,
+    uint32_t aConnectionFlags = mozIStorageService::CONNECTION_DEFAULT);
+
+class AsyncStatementSpinner : public mozIStorageStatementCallback,
+                              public mozIStorageCompletionCallback {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_MOZISTORAGESTATEMENTCALLBACK
+  NS_DECL_MOZISTORAGECOMPLETIONCALLBACK
+
+  AsyncStatementSpinner();
+
+  void SpinUntilCompleted();
+
+  uint16_t completionReason;
+
+ protected:
+  virtual ~AsyncStatementSpinner() = default;
+  volatile bool mCompleted;
+};
+
+class AsyncCompletionSpinner : public mozIStorageCompletionCallback {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_MOZISTORAGECOMPLETIONCALLBACK
+
+  AsyncCompletionSpinner();
+
+  void SpinUntilCompleted();
+
+  nsresult mCompletionReason;
+  nsCOMPtr<nsISupports> mCompletionValue;
+
+ protected:
+  virtual ~AsyncCompletionSpinner() = default;
+  volatile bool mCompleted;
+};
+
+#define NS_DECL_ASYNCSTATEMENTSPINNER \
+  NS_IMETHOD HandleResult(mozIStorageResultSet* aResultSet) override;
+
+////////////////////////////////////////////////////////////////////////////////
+//// Async Helpers
+
+/**
+ * Execute an async statement, blocking the main thread until we get the
+ * callback completion notification.
+ */
+void blocking_async_execute(mozIStorageBaseStatement* stmt);
+
+/**
+ * Invoke AsyncClose on the given connection, blocking the main thread until we
+ * get the completion notification.
+ */
+void blocking_async_close(mozIStorageConnection* db);
+
+////////////////////////////////////////////////////////////////////////////////
+//// Mutex Watching
+
+/**
+ * Verify that mozIStorageAsyncStatement's life-cycle never triggers a mutex on
+ * the caller (generally main) thread.  We do this by decorating the sqlite
+ * mutex logic with our own code that checks what thread it is being invoked on
+ * and sets a flag if it is invoked on the main thread.  We are able to easily
+ * decorate the SQLite mutex logic because SQLite allows us to retrieve the
+ * current function pointers being used and then provide a new set.
+ */
+
+extern sqlite3_mutex_methods orig_mutex_methods;
+extern sqlite3_mutex_methods wrapped_mutex_methods;
+
+extern bool mutex_used_on_watched_thread;
+extern PRThread* watched_thread;
+/**
+ * Ugly hack to let us figure out what a connection's async thread is.  If we
+ * were MOZILLA_INTERNAL_API and linked as such we could just include
+ * mozStorageConnection.h and just ask Connection directly.  But that turns out
+ * poorly.
+ *
+ * When the thread a mutex is invoked on isn't watched_thread we save it to this
+ * variable.
+ */
+extern nsIThread* last_non_watched_thread;
+
+/**
+ * Set a flag if the mutex is used on the thread we are watching, but always
+ * call the real mutex function.
+ */
+extern "C" void wrapped_MutexEnter(sqlite3_mutex* mutex);
+
+extern "C" int wrapped_MutexTry(sqlite3_mutex* mutex);
+
+class HookSqliteMutex {
+ public:
+  HookSqliteMutex() {
+    // We need to initialize and teardown SQLite to get it to set up the
+    // default mutex handlers for us so we can steal them and wrap them.
+    do_check_ok(sqlite3_initialize());
+    do_check_ok(sqlite3_shutdown());
+    do_check_ok(::sqlite3_config(SQLITE_CONFIG_GETMUTEX, &orig_mutex_methods));
+    do_check_ok(
+        ::sqlite3_config(SQLITE_CONFIG_GETMUTEX, &wrapped_mutex_methods));
+    wrapped_mutex_methods.xMutexEnter = wrapped_MutexEnter;
+    wrapped_mutex_methods.xMutexTry = wrapped_MutexTry;
+    do_check_ok(::sqlite3_config(SQLITE_CONFIG_MUTEX, &wrapped_mutex_methods));
+  }
+
+  ~HookSqliteMutex() {
+    do_check_ok(sqlite3_shutdown());
+    do_check_ok(::sqlite3_config(SQLITE_CONFIG_MUTEX, &orig_mutex_methods));
+    do_check_ok(sqlite3_initialize());
+  }
+};
+
+/**
+ * Call to clear the watch state and to set the watching against this thread.
+ *
+ * Check |mutex_used_on_watched_thread| to see if the mutex has fired since
+ * this method was last called.  Since we're talking about the current thread,
+ * there are no race issues to be concerned about
+ */
+void watch_for_mutex_use_on_this_thread();
+
+////////////////////////////////////////////////////////////////////////////////
+//// Thread Wedgers
+
+/**
+ * A runnable that blocks until code on another thread invokes its unwedge
+ * method.  By dispatching this to a thread you can ensure that no subsequent
+ * runnables dispatched to the thread will execute until you invoke unwedge.
+ *
+ * The wedger is self-dispatching, just construct it with its target.
+ */
+class ThreadWedger : public mozilla::Runnable {
+ public:
+  explicit ThreadWedger(nsIEventTarget* aTarget)
+      : mozilla::Runnable("ThreadWedger"),
+        mReentrantMonitor("thread wedger"),
+        unwedged(false) {
+    aTarget->Dispatch(this, aTarget->NS_DISPATCH_NORMAL);
+  }
+
+  NS_IMETHOD Run() override {
+    mozilla::ReentrantMonitorAutoEnter automon(mReentrantMonitor);
+
+    if (!unwedged) automon.Wait();
+
+    return NS_OK;
+  }
+
+  void unwedge() {
+    mozilla::ReentrantMonitorAutoEnter automon(mReentrantMonitor);
+    unwedged = true;
+    automon.Notify();
+  }
+
+ private:
+  mozilla::ReentrantMonitor mReentrantMonitor MOZ_UNANNOTATED;
+  bool unwedged;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Async Helpers
+
+/**
+ * A horrible hack to figure out what the connection's async thread is.  By
+ * creating a statement and async dispatching we can tell from the mutex who
+ * is the async thread, PRThread style.  Then we map that to an nsIThread.
+ */
+already_AddRefed<nsIThread> get_conn_async_thread(mozIStorageConnection* db);
+
+#endif  // storage_test_harness_h__
diff --git a/storage/test/gtest/test_AsXXX_helpers.cpp b/storage/test/gtest/test_AsXXX_helpers.cpp
new file mode 100644
index 0000000000..2320b8383c
--- /dev/null
+++ b/storage/test/gtest/test_AsXXX_helpers.cpp
@@ -0,0 +1,111 @@
+/*
+ *Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+#include "storage_test_harness.h"
+#include "mozIStorageRow.h"
+#include "mozIStorageResultSet.h"
+#include "nsComponentManagerUtils.h"
+
+/**
+ * This file tests AsXXX (AsInt32, AsInt64, ...) helpers.
+ */
+
+////////////////////////////////////////////////////////////////////////////////
+//// Event Loop Spinning
+
+class Spinner : public AsyncStatementSpinner {
+ public:
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_ASYNCSTATEMENTSPINNER
+  Spinner() {}
+
+ protected:
+  ~Spinner() override = default;
+};
+
+NS_IMPL_ISUPPORTS_INHERITED0(Spinner, AsyncStatementSpinner)
+
+NS_IMETHODIMP
+Spinner::HandleResult(mozIStorageResultSet* aResultSet) {
+  nsCOMPtr<mozIStorageRow> row;
+  do_check_true(NS_SUCCEEDED(aResultSet->GetNextRow(getter_AddRefs(row))) &&
+                row);
+
+  do_check_eq(row->AsInt32(0), 0);
+  do_check_eq(row->AsInt64(0), 0);
+  do_check_eq(row->AsDouble(0), 0.0);
+
+  uint32_t len = 100;
+  do_check_eq(row->AsSharedUTF8String(0, &len), (const char*)nullptr);
+  do_check_eq(len, 0);
+  len = 100;
+  do_check_eq(row->AsSharedWString(0, &len), (const char16_t*)nullptr);
+  do_check_eq(len, 0);
+  len = 100;
+  do_check_eq(row->AsSharedBlob(0, &len), (const uint8_t*)nullptr);
+  do_check_eq(len, 0);
+
+  do_check_eq(row->IsNull(0), true);
+  return NS_OK;
+}
+
+TEST(storage_AsXXX_helpers, NULLFallback)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  nsCOMPtr<mozIStorageStatement> stmt;
+  (void)db->CreateStatement("SELECT NULL"_ns, getter_AddRefs(stmt));
+
+  nsCOMPtr<mozIStorageValueArray> valueArray = do_QueryInterface(stmt);
+  do_check_true(valueArray);
+
+  bool hasMore;
+  do_check_true(NS_SUCCEEDED(stmt->ExecuteStep(&hasMore)) && hasMore);
+
+  do_check_eq(stmt->AsInt32(0), 0);
+  do_check_eq(stmt->AsInt64(0), 0);
+  do_check_eq(stmt->AsDouble(0), 0.0);
+  uint32_t len = 100;
+  do_check_eq(stmt->AsSharedUTF8String(0, &len), (const char*)nullptr);
+  do_check_eq(len, 0);
+  len = 100;
+  do_check_eq(stmt->AsSharedWString(0, &len), (const char16_t*)nullptr);
+  do_check_eq(len, 0);
+  len = 100;
+  do_check_eq(stmt->AsSharedBlob(0, &len), (const uint8_t*)nullptr);
+  do_check_eq(len, 0);
+  do_check_eq(stmt->IsNull(0), true);
+
+  do_check_eq(valueArray->AsInt32(0), 0);
+  do_check_eq(valueArray->AsInt64(0), 0);
+  do_check_eq(valueArray->AsDouble(0), 0.0);
+  len = 100;
+  do_check_eq(valueArray->AsSharedUTF8String(0, &len), (const char*)nullptr);
+  do_check_eq(len, 0);
+  len = 100;
+  do_check_eq(valueArray->AsSharedWString(0, &len), (const char16_t*)nullptr);
+  do_check_eq(len, 0);
+  len = 100;
+  do_check_eq(valueArray->AsSharedBlob(0, &len), (const uint8_t*)nullptr);
+  do_check_eq(len, 0);
+  do_check_eq(valueArray->IsNull(0), true);
+}
+
+TEST(storage_AsXXX_helpers, asyncNULLFallback)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  nsCOMPtr<mozIStorageAsyncStatement> stmt;
+  (void)db->CreateAsyncStatement("SELECT NULL"_ns, getter_AddRefs(stmt));
+
+  nsCOMPtr<mozIStoragePendingStatement> pendingStmt;
+  do_check_true(
+      NS_SUCCEEDED(stmt->ExecuteAsync(nullptr, getter_AddRefs(pendingStmt))));
+  do_check_true(pendingStmt);
+  stmt->Finalize();
+  RefPtr<Spinner> asyncSpin(new Spinner());
+  db->AsyncClose(asyncSpin);
+  asyncSpin->SpinUntilCompleted();
+}
diff --git a/storage/test/gtest/test_StatementCache.cpp b/storage/test/gtest/test_StatementCache.cpp
new file mode 100644
index 0000000000..9908a34d79
--- /dev/null
+++ b/storage/test/gtest/test_StatementCache.cpp
@@ -0,0 +1,132 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "storage_test_harness.h"
+
+#include "mozilla/Attributes.h"
+#include "mozilla/storage/StatementCache.h"
+using namespace mozilla::storage;
+
+/**
+ * This file test our statement cache in StatementCache.h.
+ */
+
+////////////////////////////////////////////////////////////////////////////////
+//// Helpers
+
+class SyncCache : public StatementCache<mozIStorageStatement> {
+ public:
+  explicit SyncCache(nsCOMPtr<mozIStorageConnection>& aConnection)
+      : StatementCache<mozIStorageStatement>(aConnection) {}
+};
+
+class AsyncCache : public StatementCache<mozIStorageAsyncStatement> {
+ public:
+  explicit AsyncCache(nsCOMPtr<mozIStorageConnection>& aConnection)
+      : StatementCache<mozIStorageAsyncStatement>(aConnection) {}
+};
+
+/**
+ * Wraps nsCString so we can not implement the same functions twice for each
+ * type.
+ */
+class StringWrapper : public nsCString {
+ public:
+  MOZ_IMPLICIT StringWrapper(const char* aOther) { this->Assign(aOther); }
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Test Functions
+
+// This is some gtest magic that allows us to parameterize tests by |const
+// char[]| and |StringWrapper|.
+template <typename T>
+class storage_StatementCache : public ::testing::Test {};
+typedef ::testing::Types<const char[], StringWrapper> TwoStringTypes;
+
+TYPED_TEST_SUITE(storage_StatementCache, TwoStringTypes);
+TYPED_TEST(storage_StatementCache, GetCachedStatement) {
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+  SyncCache cache(db);
+
+  TypeParam sql = "SELECT * FROM sqlite_master";
+
+  // Make sure we get a statement back with the right state.
+  nsCOMPtr<mozIStorageStatement> stmt = cache.GetCachedStatement(sql);
+  do_check_true(stmt);
+  int32_t state;
+  do_check_success(stmt->GetState(&state));
+  do_check_eq(mozIStorageBaseStatement::MOZ_STORAGE_STATEMENT_READY, state);
+
+  // Check to make sure we get the same copy the second time we ask.
+  nsCOMPtr<mozIStorageStatement> stmt2 = cache.GetCachedStatement(sql);
+  do_check_true(stmt2);
+  do_check_eq(stmt.get(), stmt2.get());
+}
+
+TYPED_TEST_SUITE(storage_StatementCache, TwoStringTypes);
+TYPED_TEST(storage_StatementCache, FinalizeStatements) {
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+  SyncCache cache(db);
+
+  TypeParam sql = "SELECT * FROM sqlite_master";
+
+  // Get a statement, and then tell the cache to finalize.
+  nsCOMPtr<mozIStorageStatement> stmt = cache.GetCachedStatement(sql);
+  do_check_true(stmt);
+
+  cache.FinalizeStatements();
+
+  // We should be in an invalid state at this point.
+  int32_t state;
+  do_check_success(stmt->GetState(&state));
+  do_check_eq(mozIStorageBaseStatement::MOZ_STORAGE_STATEMENT_INVALID, state);
+
+  // Should be able to close the database now too.
+  do_check_success(db->Close());
+}
+
+TYPED_TEST_SUITE(storage_StatementCache, TwoStringTypes);
+TYPED_TEST(storage_StatementCache, GetCachedAsyncStatement) {
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+  AsyncCache cache(db);
+
+  TypeParam sql = "SELECT * FROM sqlite_master";
+
+  // Make sure we get a statement back with the right state.
+  nsCOMPtr<mozIStorageAsyncStatement> stmt = cache.GetCachedStatement(sql);
+  do_check_true(stmt);
+  int32_t state;
+  do_check_success(stmt->GetState(&state));
+  do_check_eq(mozIStorageBaseStatement::MOZ_STORAGE_STATEMENT_READY, state);
+
+  // Check to make sure we get the same copy the second time we ask.
+  nsCOMPtr<mozIStorageAsyncStatement> stmt2 = cache.GetCachedStatement(sql);
+  do_check_true(stmt2);
+  do_check_eq(stmt.get(), stmt2.get());
+}
+
+TYPED_TEST_SUITE(storage_StatementCache, TwoStringTypes);
+TYPED_TEST(storage_StatementCache, FinalizeAsyncStatements) {
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+  AsyncCache cache(db);
+
+  TypeParam sql = "SELECT * FROM sqlite_master";
+
+  // Get a statement, and then tell the cache to finalize.
+  nsCOMPtr<mozIStorageAsyncStatement> stmt = cache.GetCachedStatement(sql);
+  do_check_true(stmt);
+
+  cache.FinalizeStatements();
+
+  // We should be in an invalid state at this point.
+  int32_t state;
+  do_check_success(stmt->GetState(&state));
+  do_check_eq(mozIStorageBaseStatement::MOZ_STORAGE_STATEMENT_INVALID, state);
+
+  // Should be able to close the database now too.
+  do_check_success(db->AsyncClose(nullptr));
+}
diff --git a/storage/test/gtest/test_asyncStatementExecution_transaction.cpp b/storage/test/gtest/test_asyncStatementExecution_transaction.cpp
new file mode 100644
index 0000000000..0e7dec1e8a
--- /dev/null
+++ b/storage/test/gtest/test_asyncStatementExecution_transaction.cpp
@@ -0,0 +1,445 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+#include "storage_test_harness.h"
+
+#include "mozStorageConnection.h"
+
+#include "sqlite3.h"
+
+using namespace mozilla;
+using namespace mozilla::storage;
+
+////////////////////////////////////////////////////////////////////////////////
+//// Helpers
+
+/**
+ * Commit hook to detect transactions.
+ *
+ * @param aArg
+ *        An integer pointer that will be incremented for each commit.
+ */
+int commit_hook(void* aArg) {
+  int* arg = static_cast<int*>(aArg);
+  (*arg)++;
+  return 0;
+}
+
+/**
+ * Executes the passed-in statements and checks if a transaction is created.
+ * When done statements are finalized and database connection is closed.
+ *
+ * @param aDB
+ *        The database connection.
+ * @param aStmts
+ *        Vector of statements.
+ * @param aStmtsLen
+ *        Number of statements.
+ * @param aTransactionExpected
+ *        Whether a transaction is expected or not.
+ */
+void check_transaction(mozIStorageConnection* aDB,
+                       const nsTArray<RefPtr<mozIStorageBaseStatement>>& aStmts,
+                       bool aTransactionExpected) {
+  // -- install a transaction commit hook.
+  int commit = 0;
+  static_cast<Connection*>(aDB)->setCommitHook(commit_hook, &commit);
+
+  RefPtr<AsyncStatementSpinner> asyncSpin(new AsyncStatementSpinner());
+  nsCOMPtr<mozIStoragePendingStatement> asyncPend;
+  do_check_success(
+      aDB->ExecuteAsync(aStmts, asyncSpin, getter_AddRefs(asyncPend)));
+  do_check_true(asyncPend);
+
+  // -- complete the execution
+  asyncSpin->SpinUntilCompleted();
+
+  // -- uninstall the transaction commit hook.
+  static_cast<Connection*>(aDB)->setCommitHook(nullptr);
+
+  // -- check transaction
+  do_check_eq(aTransactionExpected, !!commit);
+
+  // -- check that only one transaction was created.
+  if (aTransactionExpected) {
+    do_check_eq(1, commit);
+  }
+
+  // -- cleanup
+  for (uint32_t i = 0; i < aStmts.Length(); ++i) {
+    aStmts[i]->Finalize();
+  }
+  blocking_async_close(aDB);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Tests
+
+/**
+ * Test that executing multiple readonly AsyncStatements doesn't create a
+ * transaction.
+ */
+TEST(storage_asyncStatementExecution_transaction, MultipleAsyncReadStatements)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // -- create statements and execute them
+  nsCOMPtr<mozIStorageAsyncStatement> stmt1;
+  db->CreateAsyncStatement("SELECT * FROM sqlite_master"_ns,
+                           getter_AddRefs(stmt1));
+
+  nsCOMPtr<mozIStorageAsyncStatement> stmt2;
+  db->CreateAsyncStatement("SELECT * FROM sqlite_master"_ns,
+                           getter_AddRefs(stmt2));
+
+  nsTArray<RefPtr<mozIStorageBaseStatement>> stmts = {
+      ToRefPtr(std::move(stmt1)),
+      ToRefPtr(std::move(stmt2)),
+  };
+
+  check_transaction(db, stmts.Clone(), false);
+}
+
+/**
+ * Test that executing multiple readonly Statements doesn't create a
+ * transaction.
+ */
+TEST(storage_asyncStatementExecution_transaction, MultipleReadStatements)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // -- create statements and execute them
+  nsCOMPtr<mozIStorageStatement> stmt1;
+  db->CreateStatement("SELECT * FROM sqlite_master"_ns, getter_AddRefs(stmt1));
+
+  nsCOMPtr<mozIStorageStatement> stmt2;
+  db->CreateStatement("SELECT * FROM sqlite_master"_ns, getter_AddRefs(stmt2));
+
+  nsTArray<RefPtr<mozIStorageBaseStatement>> stmts = {
+      ToRefPtr(std::move(stmt1)),
+      ToRefPtr(std::move(stmt2)),
+  };
+
+  check_transaction(db, stmts, false);
+}
+
+/**
+ * Test that executing multiple AsyncStatements causing writes creates a
+ * transaction.
+ */
+TEST(storage_asyncStatementExecution_transaction,
+     MultipleAsyncReadWriteStatements)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // -- create statements and execute them
+  nsCOMPtr<mozIStorageAsyncStatement> stmt1;
+  db->CreateAsyncStatement("SELECT * FROM sqlite_master"_ns,
+                           getter_AddRefs(stmt1));
+
+  nsCOMPtr<mozIStorageAsyncStatement> stmt2;
+  db->CreateAsyncStatement("CREATE TABLE test (id INTEGER PRIMARY KEY)"_ns,
+                           getter_AddRefs(stmt2));
+
+  nsTArray<RefPtr<mozIStorageBaseStatement>> stmts = {
+      ToRefPtr(std::move(stmt1)),
+      ToRefPtr(std::move(stmt2)),
+  };
+
+  check_transaction(db, stmts, true);
+}
+
+/**
+ * Test that executing multiple Statements causing writes creates a transaction.
+ */
+TEST(storage_asyncStatementExecution_transaction, MultipleReadWriteStatements)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // -- create statements and execute them
+  nsCOMPtr<mozIStorageStatement> stmt1;
+  db->CreateStatement("SELECT * FROM sqlite_master"_ns, getter_AddRefs(stmt1));
+
+  nsCOMPtr<mozIStorageStatement> stmt2;
+  db->CreateStatement("CREATE TABLE test (id INTEGER PRIMARY KEY)"_ns,
+                      getter_AddRefs(stmt2));
+
+  nsTArray<RefPtr<mozIStorageBaseStatement>> stmts = {
+      ToRefPtr(std::move(stmt1)),
+      ToRefPtr(std::move(stmt2)),
+  };
+
+  check_transaction(db, stmts, true);
+}
+
+/**
+ * Test that executing multiple AsyncStatements causing writes creates a
+ * single transaction.
+ */
+TEST(storage_asyncStatementExecution_transaction, MultipleAsyncWriteStatements)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // -- create statements and execute them
+  nsCOMPtr<mozIStorageAsyncStatement> stmt1;
+  db->CreateAsyncStatement("CREATE TABLE test1 (id INTEGER PRIMARY KEY)"_ns,
+                           getter_AddRefs(stmt1));
+
+  nsCOMPtr<mozIStorageAsyncStatement> stmt2;
+  db->CreateAsyncStatement("CREATE TABLE test2 (id INTEGER PRIMARY KEY)"_ns,
+                           getter_AddRefs(stmt2));
+
+  nsTArray<RefPtr<mozIStorageBaseStatement>> stmts = {
+      ToRefPtr(std::move(stmt1)),
+      ToRefPtr(std::move(stmt2)),
+  };
+
+  check_transaction(db, stmts, true);
+}
+
+/**
+ * Test that executing multiple Statements causing writes creates a
+ * single transaction.
+ */
+TEST(storage_asyncStatementExecution_transaction, MultipleWriteStatements)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // -- create statements and execute them
+  nsCOMPtr<mozIStorageStatement> stmt1;
+  db->CreateStatement("CREATE TABLE test1 (id INTEGER PRIMARY KEY)"_ns,
+                      getter_AddRefs(stmt1));
+
+  nsCOMPtr<mozIStorageStatement> stmt2;
+  db->CreateStatement("CREATE TABLE test2 (id INTEGER PRIMARY KEY)"_ns,
+                      getter_AddRefs(stmt2));
+
+  nsTArray<RefPtr<mozIStorageBaseStatement>> stmts = {
+      ToRefPtr(std::move(stmt1)),
+      ToRefPtr(std::move(stmt2)),
+  };
+
+  check_transaction(db, stmts, true);
+}
+
+/**
+ * Test that executing a single read-only AsyncStatement doesn't create a
+ * transaction.
+ */
+TEST(storage_asyncStatementExecution_transaction, SingleAsyncReadStatement)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // -- create statements and execute them
+  nsCOMPtr<mozIStorageAsyncStatement> stmt;
+  db->CreateAsyncStatement("SELECT * FROM sqlite_master"_ns,
+                           getter_AddRefs(stmt));
+
+  nsTArray<RefPtr<mozIStorageBaseStatement>> stmts = {
+      ToRefPtr(std::move(stmt)),
+  };
+
+  check_transaction(db, stmts, false);
+}
+
+/**
+ * Test that executing a single read-only Statement doesn't create a
+ * transaction.
+ */
+TEST(storage_asyncStatementExecution_transaction, SingleReadStatement)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // -- create statements and execute them
+  nsCOMPtr<mozIStorageStatement> stmt;
+  db->CreateStatement("SELECT * FROM sqlite_master"_ns, getter_AddRefs(stmt));
+
+  nsTArray<RefPtr<mozIStorageBaseStatement>> stmts = {
+      ToRefPtr(std::move(stmt)),
+  };
+
+  check_transaction(db, stmts, false);
+}
+
+/**
+ * Test that executing a single AsyncStatement causing writes creates a
+ * transaction.
+ */
+TEST(storage_asyncStatementExecution_transaction, SingleAsyncWriteStatement)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // -- create statements and execute them
+  nsCOMPtr<mozIStorageAsyncStatement> stmt;
+  db->CreateAsyncStatement("CREATE TABLE test (id INTEGER PRIMARY KEY)"_ns,
+                           getter_AddRefs(stmt));
+
+  nsTArray<RefPtr<mozIStorageBaseStatement>> stmts = {
+      ToRefPtr(std::move(stmt)),
+  };
+
+  check_transaction(db, stmts, true);
+}
+
+/**
+ * Test that executing a single Statement causing writes creates a transaction.
+ */
+TEST(storage_asyncStatementExecution_transaction, SingleWriteStatement)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // -- create statements and execute them
+  nsCOMPtr<mozIStorageStatement> stmt;
+  db->CreateStatement("CREATE TABLE test (id INTEGER PRIMARY KEY)"_ns,
+                      getter_AddRefs(stmt));
+
+  nsTArray<RefPtr<mozIStorageBaseStatement>> stmts = {
+      ToRefPtr(std::move(stmt)),
+  };
+
+  check_transaction(db, stmts, true);
+}
+
+/**
+ * Test that executing a single read-only AsyncStatement with multiple params
+ * doesn't create a transaction.
+ */
+TEST(storage_asyncStatementExecution_transaction,
+     MultipleParamsAsyncReadStatement)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // -- create statements and execute them
+  nsCOMPtr<mozIStorageAsyncStatement> stmt;
+  db->CreateAsyncStatement("SELECT :param FROM sqlite_master"_ns,
+                           getter_AddRefs(stmt));
+
+  // -- bind multiple BindingParams
+  nsCOMPtr<mozIStorageBindingParamsArray> paramsArray;
+  stmt->NewBindingParamsArray(getter_AddRefs(paramsArray));
+  for (int32_t i = 0; i < 2; i++) {
+    nsCOMPtr<mozIStorageBindingParams> params;
+    paramsArray->NewBindingParams(getter_AddRefs(params));
+    params->BindInt32ByName("param"_ns, 1);
+    paramsArray->AddParams(params);
+  }
+  stmt->BindParameters(paramsArray);
+  paramsArray = nullptr;
+
+  nsTArray<RefPtr<mozIStorageBaseStatement>> stmts = {
+      ToRefPtr(std::move(stmt)),
+  };
+
+  check_transaction(db, stmts, false);
+}
+
+/**
+ * Test that executing a single read-only Statement with multiple params
+ * doesn't create a transaction.
+ */
+TEST(storage_asyncStatementExecution_transaction, MultipleParamsReadStatement)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // -- create statements and execute them
+  nsCOMPtr<mozIStorageStatement> stmt;
+  db->CreateStatement("SELECT :param FROM sqlite_master"_ns,
+                      getter_AddRefs(stmt));
+
+  // -- bind multiple BindingParams
+  nsCOMPtr<mozIStorageBindingParamsArray> paramsArray;
+  stmt->NewBindingParamsArray(getter_AddRefs(paramsArray));
+  for (int32_t i = 0; i < 2; i++) {
+    nsCOMPtr<mozIStorageBindingParams> params;
+    paramsArray->NewBindingParams(getter_AddRefs(params));
+    params->BindInt32ByName("param"_ns, 1);
+    paramsArray->AddParams(params);
+  }
+  stmt->BindParameters(paramsArray);
+  paramsArray = nullptr;
+
+  nsTArray<RefPtr<mozIStorageBaseStatement>> stmts = {
+      ToRefPtr(std::move(stmt)),
+  };
+
+  check_transaction(db, stmts, false);
+}
+
+/**
+ * Test that executing a single write AsyncStatement with multiple params
+ * creates a transaction.
+ */
+TEST(storage_asyncStatementExecution_transaction,
+     MultipleParamsAsyncWriteStatement)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // -- create a table for writes
+  nsCOMPtr<mozIStorageStatement> tableStmt;
+  db->CreateStatement("CREATE TABLE test (id INTEGER PRIMARY KEY)"_ns,
+                      getter_AddRefs(tableStmt));
+  tableStmt->Execute();
+  tableStmt->Finalize();
+
+  // -- create statements and execute them
+  nsCOMPtr<mozIStorageAsyncStatement> stmt;
+  db->CreateAsyncStatement("DELETE FROM test WHERE id = :param"_ns,
+                           getter_AddRefs(stmt));
+
+  // -- bind multiple BindingParams
+  nsCOMPtr<mozIStorageBindingParamsArray> paramsArray;
+  stmt->NewBindingParamsArray(getter_AddRefs(paramsArray));
+  for (int32_t i = 0; i < 2; i++) {
+    nsCOMPtr<mozIStorageBindingParams> params;
+    paramsArray->NewBindingParams(getter_AddRefs(params));
+    params->BindInt32ByName("param"_ns, 1);
+    paramsArray->AddParams(params);
+  }
+  stmt->BindParameters(paramsArray);
+  paramsArray = nullptr;
+
+  nsTArray<RefPtr<mozIStorageBaseStatement>> stmts = {
+      ToRefPtr(std::move(stmt)),
+  };
+
+  check_transaction(db, stmts, true);
+}
+
+/**
+ * Test that executing a single write Statement with multiple params
+ * creates a transaction.
+ */
+TEST(storage_asyncStatementExecution_transaction, MultipleParamsWriteStatement)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // -- create a table for writes
+  nsCOMPtr<mozIStorageStatement> tableStmt;
+  db->CreateStatement("CREATE TABLE test (id INTEGER PRIMARY KEY)"_ns,
+                      getter_AddRefs(tableStmt));
+  tableStmt->Execute();
+  tableStmt->Finalize();
+
+  // -- create statements and execute them
+  nsCOMPtr<mozIStorageStatement> stmt;
+  db->CreateStatement("DELETE FROM test WHERE id = :param"_ns,
+                      getter_AddRefs(stmt));
+
+  // -- bind multiple BindingParams
+  nsCOMPtr<mozIStorageBindingParamsArray> paramsArray;
+  stmt->NewBindingParamsArray(getter_AddRefs(paramsArray));
+  for (int32_t i = 0; i < 2; i++) {
+    nsCOMPtr<mozIStorageBindingParams> params;
+    paramsArray->NewBindingParams(getter_AddRefs(params));
+    params->BindInt32ByName("param"_ns, 1);
+    paramsArray->AddParams(params);
+  }
+  stmt->BindParameters(paramsArray);
+  paramsArray = nullptr;
+
+  nsTArray<RefPtr<mozIStorageBaseStatement>> stmts = {
+      ToRefPtr(std::move(stmt)),
+  };
+
+  check_transaction(db, stmts, true);
+}
diff --git a/storage/test/gtest/test_async_callbacks_with_spun_event_loops.cpp b/storage/test/gtest/test_async_callbacks_with_spun_event_loops.cpp
new file mode 100644
index 0000000000..bd437b61ec
--- /dev/null
+++ b/storage/test/gtest/test_async_callbacks_with_spun_event_loops.cpp
@@ -0,0 +1,146 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+#include "storage_test_harness.h"
+#include "prthread.h"
+#include "nsIInterfaceRequestorUtils.h"
+#include "mozilla/Attributes.h"
+
+#include "sqlite3.h"
+
+////////////////////////////////////////////////////////////////////////////////
+//// Async Helpers
+
+/**
+ * Spins the events loop for current thread until aCondition is true.
+ */
+void spin_events_loop_until_true(const bool* const aCondition) {
+  nsCOMPtr<nsIThread> thread(::do_GetCurrentThread());
+  nsresult rv = NS_OK;
+  bool processed = true;
+  while (!(*aCondition) && NS_SUCCEEDED(rv)) {
+    rv = thread->ProcessNextEvent(true, &processed);
+  }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// mozIStorageStatementCallback implementation
+
+class UnownedCallback final : public mozIStorageStatementCallback {
+ public:
+  NS_DECL_ISUPPORTS
+
+  // Whether the object has been destroyed.
+  static bool sAlive;
+  // Whether the first result was received.
+  static bool sResult;
+  // Whether an error was received.
+  static bool sError;
+
+  explicit UnownedCallback(mozIStorageConnection* aDBConn)
+      : mDBConn(aDBConn), mCompleted(false) {
+    sAlive = true;
+    sResult = false;
+    sError = false;
+  }
+
+ private:
+  ~UnownedCallback() {
+    sAlive = false;
+    blocking_async_close(mDBConn);
+  }
+
+ public:
+  NS_IMETHOD HandleResult(mozIStorageResultSet* aResultSet) override {
+    sResult = true;
+    spin_events_loop_until_true(&mCompleted);
+    if (!sAlive) {
+      MOZ_CRASH("The statement callback was destroyed prematurely.");
+    }
+    return NS_OK;
+  }
+
+  NS_IMETHOD HandleError(mozIStorageError* aError) override {
+    sError = true;
+    spin_events_loop_until_true(&mCompleted);
+    if (!sAlive) {
+      MOZ_CRASH("The statement callback was destroyed prematurely.");
+    }
+    return NS_OK;
+  }
+
+  NS_IMETHOD HandleCompletion(uint16_t aReason) override {
+    mCompleted = true;
+    return NS_OK;
+  }
+
+ protected:
+  nsCOMPtr<mozIStorageConnection> mDBConn;
+  bool mCompleted;
+};
+
+NS_IMPL_ISUPPORTS(UnownedCallback, mozIStorageStatementCallback)
+
+bool UnownedCallback::sAlive = false;
+bool UnownedCallback::sResult = false;
+bool UnownedCallback::sError = false;
+
+////////////////////////////////////////////////////////////////////////////////
+//// Tests
+
+TEST(storage_async_callbacks_with_spun_event_loops,
+     SpinEventsLoopInHandleResult)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // Create a test table and populate it.
+  nsCOMPtr<mozIStorageStatement> stmt;
+  db->CreateStatement("CREATE TABLE test (id INTEGER PRIMARY KEY)"_ns,
+                      getter_AddRefs(stmt));
+  stmt->Execute();
+  stmt->Finalize();
+
+  db->CreateStatement("INSERT INTO test (id) VALUES (?)"_ns,
+                      getter_AddRefs(stmt));
+  for (int32_t i = 0; i < 30; ++i) {
+    stmt->BindInt32ByIndex(0, i);
+    stmt->Execute();
+    stmt->Reset();
+  }
+  stmt->Finalize();
+
+  db->CreateStatement("SELECT * FROM test"_ns, getter_AddRefs(stmt));
+  nsCOMPtr<mozIStoragePendingStatement> ps;
+  do_check_success(
+      stmt->ExecuteAsync(new UnownedCallback(db), getter_AddRefs(ps)));
+  stmt->Finalize();
+
+  spin_events_loop_until_true(&UnownedCallback::sResult);
+}
+
+TEST(storage_async_callbacks_with_spun_event_loops, SpinEventsLoopInHandleError)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // Create a test table and populate it.
+  nsCOMPtr<mozIStorageStatement> stmt;
+  db->CreateStatement("CREATE TABLE test (id INTEGER PRIMARY KEY)"_ns,
+                      getter_AddRefs(stmt));
+  stmt->Execute();
+  stmt->Finalize();
+
+  db->CreateStatement("INSERT INTO test (id) VALUES (1)"_ns,
+                      getter_AddRefs(stmt));
+  stmt->Execute();
+  stmt->Finalize();
+
+  // This will cause a constraint error.
+  db->CreateStatement("INSERT INTO test (id) VALUES (1)"_ns,
+                      getter_AddRefs(stmt));
+  nsCOMPtr<mozIStoragePendingStatement> ps;
+  do_check_success(
+      stmt->ExecuteAsync(new UnownedCallback(db), getter_AddRefs(ps)));
+  stmt->Finalize();
+
+  spin_events_loop_until_true(&UnownedCallback::sError);
+}
diff --git a/storage/test/gtest/test_async_thread_naming.cpp b/storage/test/gtest/test_async_thread_naming.cpp
new file mode 100644
index 0000000000..77d088f3e5
--- /dev/null
+++ b/storage/test/gtest/test_async_thread_naming.cpp
@@ -0,0 +1,230 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsVariant.h"
+#include "storage_test_harness.h"
+#include "nsThreadUtils.h"
+#include "nsIURI.h"
+#include "nsIFileURL.h"
+#include "nsIVariant.h"
+#include "nsNetUtil.h"
+
+////////////////////////////////////////////////////////////////////////////////
+//// Tests
+
+TEST(storage_async_thread_naming, MemoryDatabase)
+{
+  HookSqliteMutex hook;
+
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  nsCOMPtr<nsIThread> target(get_conn_async_thread(db));
+  do_check_true(target);
+  PRThread* prThread;
+  target->GetPRThread(&prThread);
+  do_check_true(prThread);
+  nsAutoCString name(PR_GetThreadName(prThread));
+  printf("%s", name.get());
+  do_check_true(StringBeginsWith(name, "sqldb:memory"_ns));
+
+  blocking_async_close(db);
+}
+
+TEST(storage_async_thread_naming, FileDatabase)
+{
+  HookSqliteMutex hook;
+
+  nsAutoString filename(u"test_thread_name.sqlite"_ns);
+  nsCOMPtr<nsIFile> dbFile;
+  do_check_success(NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR,
+                                          getter_AddRefs(dbFile)));
+  do_check_success(dbFile->Append(filename));
+  nsCOMPtr<mozIStorageService> ss = getService();
+  nsCOMPtr<mozIStorageConnection> conn;
+  do_check_success(ss->OpenDatabase(dbFile, 0, getter_AddRefs(conn)));
+
+  nsCOMPtr<nsIThread> target(get_conn_async_thread(conn));
+  do_check_true(target);
+  PRThread* prThread;
+  target->GetPRThread(&prThread);
+  do_check_true(prThread);
+  nsAutoCString name(PR_GetThreadName(prThread));
+  nsAutoCString expected("sqldb:"_ns);
+  expected.Append(NS_ConvertUTF16toUTF8(filename));
+  do_check_true(StringBeginsWith(name, expected));
+
+  {
+    nsCOMPtr<mozIStorageConnection> clone;
+    do_check_success(conn->Clone(true, getter_AddRefs(clone)));
+    nsCOMPtr<nsIThread> target(get_conn_async_thread(conn));
+    do_check_true(target);
+    PRThread* prThread;
+    target->GetPRThread(&prThread);
+    do_check_true(prThread);
+    nsAutoCString name(PR_GetThreadName(prThread));
+    nsAutoCString expected("sqldb:"_ns);
+    expected.Append(NS_ConvertUTF16toUTF8(filename));
+    do_check_true(StringBeginsWith(name, expected));
+    blocking_async_close(clone);
+  }
+
+  blocking_async_close(conn);
+}
+
+TEST(storage_async_thread_naming, FileUnsharedDatabase)
+{
+  HookSqliteMutex hook;
+
+  nsAutoString filename(u"test_thread_name.sqlite"_ns);
+  nsCOMPtr<nsIFile> dbFile;
+  do_check_success(NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR,
+                                          getter_AddRefs(dbFile)));
+  do_check_success(dbFile->Append(filename));
+  nsCOMPtr<mozIStorageService> ss = getService();
+  nsCOMPtr<mozIStorageConnection> conn;
+  do_check_success(ss->OpenUnsharedDatabase(dbFile, 0, getter_AddRefs(conn)));
+
+  nsCOMPtr<nsIThread> target(get_conn_async_thread(conn));
+  do_check_true(target);
+  PRThread* prThread;
+  target->GetPRThread(&prThread);
+  do_check_true(prThread);
+  nsAutoCString name(PR_GetThreadName(prThread));
+  nsAutoCString expected("sqldb:"_ns);
+  expected.Append(NS_ConvertUTF16toUTF8(filename));
+  do_check_true(StringBeginsWith(name, expected));
+
+  blocking_async_close(conn);
+}
+
+TEST(storage_async_thread_naming, FileURLDatabase)
+{
+  HookSqliteMutex hook;
+
+  nsAutoString filename(u"test_thread_name.sqlite"_ns);
+  nsCOMPtr<nsIFile> dbFile;
+  do_check_success(NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR,
+                                          getter_AddRefs(dbFile)));
+  do_check_success(dbFile->Append(filename));
+  nsCOMPtr<nsIURI> uri;
+  do_check_success(NS_NewFileURI(getter_AddRefs(uri), dbFile));
+  nsCOMPtr<nsIFileURL> fileUrl = do_QueryInterface(uri);
+  nsCOMPtr<mozIStorageService> ss = getService();
+  nsCOMPtr<mozIStorageConnection> conn;
+  do_check_success(ss->OpenDatabaseWithFileURL(fileUrl, EmptyCString(), 0,
+                                               getter_AddRefs(conn)));
+
+  nsCOMPtr<nsIThread> target(get_conn_async_thread(conn));
+  do_check_true(target);
+  PRThread* prThread;
+  target->GetPRThread(&prThread);
+  do_check_true(prThread);
+  nsAutoCString name(PR_GetThreadName(prThread));
+  nsAutoCString expected("sqldb:"_ns);
+  expected.Append(NS_ConvertUTF16toUTF8(filename));
+  do_check_true(StringBeginsWith(name, expected));
+
+  blocking_async_close(conn);
+}
+
+TEST(storage_async_thread_naming, OverrideFileURLDatabase)
+{
+  HookSqliteMutex hook;
+
+  nsAutoString filename(u"test_thread_name.sqlite"_ns);
+  nsCOMPtr<nsIFile> dbFile;
+  do_check_success(NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR,
+                                          getter_AddRefs(dbFile)));
+  do_check_success(dbFile->Append(filename));
+  nsCOMPtr<nsIURI> uri;
+  do_check_success(NS_NewFileURI(getter_AddRefs(uri), dbFile));
+  nsCOMPtr<nsIFileURL> fileUrl = do_QueryInterface(uri);
+  nsCOMPtr<mozIStorageService> ss = getService();
+  nsCOMPtr<mozIStorageConnection> conn;
+  nsAutoCString override("override"_ns);
+  do_check_success(
+      ss->OpenDatabaseWithFileURL(fileUrl, override, 0, getter_AddRefs(conn)));
+
+  nsCOMPtr<nsIThread> target(get_conn_async_thread(conn));
+  do_check_true(target);
+  PRThread* prThread;
+  target->GetPRThread(&prThread);
+  do_check_true(prThread);
+  nsAutoCString name(PR_GetThreadName(prThread));
+  nsAutoCString expected("sqldb:"_ns);
+  expected.Append(override);
+  do_check_true(StringBeginsWith(name, expected));
+
+  blocking_async_close(conn);
+}
+
+TEST(storage_async_thread_naming, AsyncOpenDatabase)
+{
+  HookSqliteMutex hook;
+
+  nsAutoString filename(u"test_thread_name.sqlite"_ns);
+  nsCOMPtr<nsIFile> dbFile;
+  do_check_success(NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR,
+                                          getter_AddRefs(dbFile)));
+  do_check_success(dbFile->Append(filename));
+  nsCOMPtr<mozIStorageService> ss = getService();
+
+  RefPtr<AsyncCompletionSpinner> completionSpinner =
+      new AsyncCompletionSpinner();
+  RefPtr<nsVariant> variant = new nsVariant();
+  variant->SetAsInterface(NS_GET_IID(nsIFile), dbFile);
+  do_check_success(ss->OpenAsyncDatabase(variant, 0, 0, completionSpinner));
+  completionSpinner->SpinUntilCompleted();
+  nsCOMPtr<mozIStorageConnection> conn(
+      do_QueryInterface(completionSpinner->mCompletionValue));
+  nsCOMPtr<nsIThread> target(get_conn_async_thread(conn));
+  do_check_true(target);
+  PRThread* prThread;
+  target->GetPRThread(&prThread);
+  do_check_true(prThread);
+  nsAutoCString name(PR_GetThreadName(prThread));
+  nsAutoCString expected("sqldb:"_ns);
+  expected.Append(NS_ConvertUTF16toUTF8(filename));
+  do_check_true(StringBeginsWith(name, expected));
+
+  blocking_async_close(conn);
+}
+
+TEST(storage_async_thread_naming, AsyncClone)
+{
+  HookSqliteMutex hook;
+
+  nsAutoString filename(u"test_thread_name.sqlite"_ns);
+  nsCOMPtr<nsIFile> dbFile;
+  do_check_success(NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR,
+                                          getter_AddRefs(dbFile)));
+  do_check_success(dbFile->Append(filename));
+  nsCOMPtr<mozIStorageService> ss = getService();
+
+  nsCOMPtr<mozIStorageConnection> conn;
+  do_check_success(ss->OpenDatabase(dbFile, 0, getter_AddRefs(conn)));
+
+  RefPtr<AsyncCompletionSpinner> completionSpinner =
+      new AsyncCompletionSpinner();
+  RefPtr<nsVariant> variant = new nsVariant();
+  variant->SetAsInterface(NS_GET_IID(nsIFile), dbFile);
+  do_check_success(conn->AsyncClone(true, completionSpinner));
+  completionSpinner->SpinUntilCompleted();
+  nsCOMPtr<mozIStorageConnection> clone(
+      do_QueryInterface(completionSpinner->mCompletionValue));
+  nsCOMPtr<nsIThread> target(get_conn_async_thread(clone));
+  do_check_true(target);
+  PRThread* prThread;
+  target->GetPRThread(&prThread);
+  do_check_true(prThread);
+  nsAutoCString name(PR_GetThreadName(prThread));
+  nsAutoCString expected("sqldb:"_ns);
+  expected.Append(NS_ConvertUTF16toUTF8(filename));
+  do_check_true(StringBeginsWith(name, expected));
+
+  blocking_async_close(conn);
+  blocking_async_close(clone);
+}
diff --git a/storage/test/gtest/test_binding_params.cpp b/storage/test/gtest/test_binding_params.cpp
new file mode 100644
index 0000000000..a9ca1799f9
--- /dev/null
+++ b/storage/test/gtest/test_binding_params.cpp
@@ -0,0 +1,186 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "storage_test_harness.h"
+
+#include "mozilla/ArrayUtils.h"
+#include "mozStorageHelper.h"
+
+using namespace mozilla;
+
+/**
+ * This file tests binding and reading out string parameters through the
+ * mozIStorageStatement API.
+ */
+
+TEST(storage_binding_params, ASCIIString)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // Create table with a single string column.
+  (void)db->ExecuteSimpleSQL("CREATE TABLE test (str STRING)"_ns);
+
+  // Create statements to INSERT and SELECT the string.
+  nsCOMPtr<mozIStorageStatement> insert, select;
+  (void)db->CreateStatement("INSERT INTO test (str) VALUES (?1)"_ns,
+                            getter_AddRefs(insert));
+  (void)db->CreateStatement("SELECT str FROM test"_ns, getter_AddRefs(select));
+
+  // Roundtrip a string through the table, and ensure it comes out as expected.
+  nsAutoCString inserted("I'm an ASCII string");
+  {
+    mozStorageStatementScoper scoper(insert);
+    bool hasResult;
+    do_check_true(NS_SUCCEEDED(insert->BindUTF8StringByIndex(0, inserted)));
+    do_check_true(NS_SUCCEEDED(insert->ExecuteStep(&hasResult)));
+    do_check_false(hasResult);
+  }
+
+  nsAutoCString result;
+  {
+    mozStorageStatementScoper scoper(select);
+    bool hasResult;
+    do_check_true(NS_SUCCEEDED(select->ExecuteStep(&hasResult)));
+    do_check_true(hasResult);
+    do_check_true(NS_SUCCEEDED(select->GetUTF8String(0, result)));
+  }
+
+  do_check_true(result == inserted);
+
+  (void)db->ExecuteSimpleSQL("DELETE FROM test"_ns);
+}
+
+TEST(storage_binding_params, CString)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // Create table with a single string column.
+  (void)db->ExecuteSimpleSQL("CREATE TABLE test (str STRING)"_ns);
+
+  // Create statements to INSERT and SELECT the string.
+  nsCOMPtr<mozIStorageStatement> insert, select;
+  (void)db->CreateStatement("INSERT INTO test (str) VALUES (?1)"_ns,
+                            getter_AddRefs(insert));
+  (void)db->CreateStatement("SELECT str FROM test"_ns, getter_AddRefs(select));
+
+  // Roundtrip a string through the table, and ensure it comes out as expected.
+  static const char sCharArray[] =
+      "I'm not a \xff\x00\xac\xde\xbb ASCII string!";
+  nsAutoCString inserted(sCharArray, ArrayLength(sCharArray) - 1);
+  do_check_true(inserted.Length() == ArrayLength(sCharArray) - 1);
+  {
+    mozStorageStatementScoper scoper(insert);
+    bool hasResult;
+    do_check_true(NS_SUCCEEDED(insert->BindUTF8StringByIndex(0, inserted)));
+    do_check_true(NS_SUCCEEDED(insert->ExecuteStep(&hasResult)));
+    do_check_false(hasResult);
+  }
+
+  {
+    nsAutoCString result;
+
+    mozStorageStatementScoper scoper(select);
+    bool hasResult;
+    do_check_true(NS_SUCCEEDED(select->ExecuteStep(&hasResult)));
+    do_check_true(hasResult);
+    do_check_true(NS_SUCCEEDED(select->GetUTF8String(0, result)));
+
+    do_check_true(result == inserted);
+  }
+
+  (void)db->ExecuteSimpleSQL("DELETE FROM test"_ns);
+}
+
+TEST(storage_binding_params, UTFStrings)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // Create table with a single string column.
+  (void)db->ExecuteSimpleSQL("CREATE TABLE test (str STRING)"_ns);
+
+  // Create statements to INSERT and SELECT the string.
+  nsCOMPtr<mozIStorageStatement> insert, select;
+  (void)db->CreateStatement("INSERT INTO test (str) VALUES (?1)"_ns,
+                            getter_AddRefs(insert));
+  (void)db->CreateStatement("SELECT str FROM test"_ns, getter_AddRefs(select));
+
+  // Roundtrip a UTF8 string through the table, using UTF8 input and output.
+  static const char sCharArray[] = R"(I'm a ûüâäç UTF8 string!)";
+  nsAutoCString insertedUTF8(sCharArray, ArrayLength(sCharArray) - 1);
+  do_check_true(insertedUTF8.Length() == ArrayLength(sCharArray) - 1);
+  NS_ConvertUTF8toUTF16 insertedUTF16(insertedUTF8);
+  do_check_true(insertedUTF8 == NS_ConvertUTF16toUTF8(insertedUTF16));
+  {
+    mozStorageStatementScoper scoper(insert);
+    bool hasResult;
+    do_check_true(NS_SUCCEEDED(insert->BindUTF8StringByIndex(0, insertedUTF8)));
+    do_check_true(NS_SUCCEEDED(insert->ExecuteStep(&hasResult)));
+    do_check_false(hasResult);
+  }
+
+  {
+    nsAutoCString result;
+
+    mozStorageStatementScoper scoper(select);
+    bool hasResult;
+    do_check_true(NS_SUCCEEDED(select->ExecuteStep(&hasResult)));
+    do_check_true(hasResult);
+    do_check_true(NS_SUCCEEDED(select->GetUTF8String(0, result)));
+
+    do_check_true(result == insertedUTF8);
+  }
+
+  // Use UTF8 input and UTF16 output.
+  {
+    nsAutoString result;
+
+    mozStorageStatementScoper scoper(select);
+    bool hasResult;
+    do_check_true(NS_SUCCEEDED(select->ExecuteStep(&hasResult)));
+    do_check_true(hasResult);
+    do_check_true(NS_SUCCEEDED(select->GetString(0, result)));
+
+    do_check_true(result == insertedUTF16);
+  }
+
+  (void)db->ExecuteSimpleSQL("DELETE FROM test"_ns);
+
+  // Roundtrip the same string using UTF16 input and UTF8 output.
+  {
+    mozStorageStatementScoper scoper(insert);
+    bool hasResult;
+    do_check_true(NS_SUCCEEDED(insert->BindStringByIndex(0, insertedUTF16)));
+    do_check_true(NS_SUCCEEDED(insert->ExecuteStep(&hasResult)));
+    do_check_false(hasResult);
+  }
+
+  {
+    nsAutoCString result;
+
+    mozStorageStatementScoper scoper(select);
+    bool hasResult;
+    do_check_true(NS_SUCCEEDED(select->ExecuteStep(&hasResult)));
+    do_check_true(hasResult);
+    do_check_true(NS_SUCCEEDED(select->GetUTF8String(0, result)));
+
+    do_check_true(result == insertedUTF8);
+  }
+
+  // Use UTF16 input and UTF16 output.
+  {
+    nsAutoString result;
+
+    mozStorageStatementScoper scoper(select);
+    bool hasResult;
+    do_check_true(NS_SUCCEEDED(select->ExecuteStep(&hasResult)));
+    do_check_true(hasResult);
+    do_check_true(NS_SUCCEEDED(select->GetString(0, result)));
+
+    do_check_true(result == insertedUTF16);
+  }
+
+  (void)db->ExecuteSimpleSQL("DELETE FROM test"_ns);
+}
diff --git a/storage/test/gtest/test_deadlock_detector.cpp b/storage/test/gtest/test_deadlock_detector.cpp
new file mode 100644
index 0000000000..2679cf26f1
--- /dev/null
+++ b/storage/test/gtest/test_deadlock_detector.cpp
@@ -0,0 +1,56 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: sw=2 ts=4 et :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Note: This file is essentially a copy of
+// xpcom/tests/gtest/TestDeadlockDetector.cpp, but all mutexes were turned into
+// SQLiteMutexes. We use #include and some macros to avoid actual source code
+// duplication.
+
+#include "mozilla/CondVar.h"
+#include "mozilla/RecursiveMutex.h"
+#include "mozilla/ReentrantMonitor.h"
+#include "SQLiteMutex.h"
+
+// We need this one so _gdb_sleep_duration is also in "storage" namespace
+#include "mozilla/gtest/MozHelpers.h"
+
+#include "gtest/gtest.h"
+
+using namespace mozilla;
+
+/**
+ * Helper class to allocate a sqlite3_mutex for our SQLiteMutex.
+ */
+class TestMutex : public mozilla::storage::SQLiteMutex {
+ public:
+  explicit TestMutex(const char* aName)
+      : mozilla::storage::SQLiteMutex(aName),
+        mInner(sqlite3_mutex_alloc(SQLITE_MUTEX_FAST)) {
+    NS_ASSERTION(mInner, "could not allocate a sqlite3_mutex");
+    initWithMutex(mInner);
+  }
+
+  ~TestMutex() { sqlite3_mutex_free(mInner); }
+
+  void Lock() { lock(); }
+
+  void Unlock() { unlock(); }
+
+ private:
+  sqlite3_mutex* mInner;
+};
+
+// These are the two macros that differentiate this file from the XPCOM one.
+#define MUTEX TestMutex
+#define TESTNAME(name) storage_##name
+
+// Bug 1473531: the test storage_DeadlockDetectorTest.storage_Sanity5DeathTest
+// times out on macosx ccov builds
+#if defined(XP_MACOSX) && defined(MOZ_CODE_COVERAGE)
+#  define DISABLE_STORAGE_SANITY5_DEATH_TEST
+#endif
+
+#include "../../../xpcom/tests/gtest/TestDeadlockDetector.cpp"
diff --git a/storage/test/gtest/test_file_perms.cpp b/storage/test/gtest/test_file_perms.cpp
new file mode 100644
index 0000000000..5e54f082ce
--- /dev/null
+++ b/storage/test/gtest/test_file_perms.cpp
@@ -0,0 +1,35 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "storage_test_harness.h"
+#include "nsIFile.h"
+#include "prio.h"
+
+/**
+ * This file tests that the file permissions of the sqlite files match what
+ * we request they be
+ */
+
+TEST(storage_file_perms, Test)
+{
+  nsCOMPtr<mozIStorageConnection> db(getDatabase());
+  nsCOMPtr<nsIFile> dbFile;
+  do_check_success(db->GetDatabaseFile(getter_AddRefs(dbFile)));
+
+  uint32_t perms = 0;
+  do_check_success(dbFile->GetPermissions(&perms));
+
+  // This reflexts the permissions defined by SQLITE_DEFAULT_FILE_PERMISSIONS in
+  // third_party/sqlite3/src/Makefile.in and must be kept in sync with that
+#ifdef ANDROID
+  do_check_true(perms == (PR_IRUSR | PR_IWUSR));
+#elif defined(XP_WIN)
+  do_check_true(perms == (PR_IRUSR | PR_IWUSR | PR_IRGRP | PR_IWGRP | PR_IROTH |
+                          PR_IWOTH));
+#else
+  do_check_true(perms == (PR_IRUSR | PR_IWUSR | PR_IRGRP | PR_IROTH));
+#endif
+}
diff --git a/storage/test/gtest/test_interruptSynchronousConnection.cpp b/storage/test/gtest/test_interruptSynchronousConnection.cpp
new file mode 100644
index 0000000000..dfa19bc86e
--- /dev/null
+++ b/storage/test/gtest/test_interruptSynchronousConnection.cpp
@@ -0,0 +1,81 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+
+#include "storage_test_harness.h"
+
+#include "mozilla/SpinEventLoopUntil.h"
+
+class SynchronousConnectionInterruptionTest : public ::testing::Test {
+ protected:
+  void SetUp() override {
+    mConnection =
+        getDatabase(nullptr, mozIStorageService::CONNECTION_INTERRUPTIBLE);
+    ASSERT_TRUE(mConnection);
+
+    ASSERT_EQ(NS_OK, NS_NewNamedThread("Test Thread", getter_AddRefs(mThread)));
+  }
+
+  void TearDown() override {
+    // We might close the database connection early in test cases.
+    mozilla::Unused << mConnection->Close();
+
+    ASSERT_EQ(NS_OK, mThread->Shutdown());
+  }
+
+  nsCOMPtr<mozIStorageConnection> mConnection;
+
+  nsCOMPtr<nsIThread> mThread;
+
+  bool mDone = false;
+};
+
+TEST_F(SynchronousConnectionInterruptionTest,
+       shouldBeAbleToInterruptInfiniteOperation) {
+  // Delay is modest because we don't want to get interrupted by
+  // some unrelated hang or memory guard
+  const uint32_t delayMs = 500;
+
+  ASSERT_EQ(NS_OK, mThread->DelayedDispatch(
+                       NS_NewRunnableFunction(
+                           "InterruptRunnable",
+                           [this]() {
+                             ASSERT_EQ(NS_OK, mConnection->Interrupt());
+                             mDone = true;
+                           }),
+                       delayMs));
+
+  const nsCString infiniteQuery =
+      "WITH RECURSIVE test(n) "
+      "AS (VALUES(1) UNION ALL SELECT n + 1 FROM test) "
+      "SELECT t.n FROM test, test AS t;"_ns;
+  nsCOMPtr<mozIStorageStatement> stmt;
+  ASSERT_EQ(NS_OK,
+            mConnection->CreateStatement(infiniteQuery, getter_AddRefs(stmt)));
+  ASSERT_EQ(NS_ERROR_ABORT, stmt->Execute());
+  ASSERT_EQ(NS_OK, stmt->Finalize());
+
+  ASSERT_TRUE(mDone);
+
+  ASSERT_EQ(NS_OK, mConnection->Close());
+}
+
+TEST_F(SynchronousConnectionInterruptionTest, interruptAfterCloseWillFail) {
+  ASSERT_EQ(NS_OK, mConnection->Close());
+
+  ASSERT_EQ(
+      NS_OK,
+      mThread->Dispatch(NS_NewRunnableFunction("InterruptRunnable", [this]() {
+        ASSERT_EQ(NS_ERROR_NOT_INITIALIZED, mConnection->Interrupt());
+        mDone = true;
+      })));
+
+  ASSERT_TRUE(mozilla::SpinEventLoopUntil("interruptAfterCloseWillFail"_ns,
+                                          [this]() { return mDone; }));
+
+  ASSERT_EQ(NS_ERROR_NOT_INITIALIZED, mConnection->Close());
+}
diff --git a/storage/test/gtest/test_mutex.cpp b/storage/test/gtest/test_mutex.cpp
new file mode 100644
index 0000000000..db1a645e09
--- /dev/null
+++ b/storage/test/gtest/test_mutex.cpp
@@ -0,0 +1,73 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "storage_test_harness.h"
+
+#include "SQLiteMutex.h"
+
+using namespace mozilla;
+using namespace mozilla::storage;
+
+/**
+ * This file test our sqlite3_mutex wrapper in SQLiteMutex.h.
+ */
+
+TEST(storage_mutex, AutoLock)
+{
+  int lockTypes[] = {
+      SQLITE_MUTEX_FAST,
+      SQLITE_MUTEX_RECURSIVE,
+  };
+  for (int lockType : lockTypes) {
+    // Get our test mutex (we have to allocate a SQLite mutex of the right type
+    // too!).
+    SQLiteMutex mutex("TestMutex");
+    sqlite3_mutex* inner = sqlite3_mutex_alloc(lockType);
+    do_check_true(inner);
+    mutex.initWithMutex(inner);
+
+    // And test that our automatic locking wrapper works as expected.
+    mutex.assertNotCurrentThreadOwns();
+    {
+      SQLiteMutexAutoLock lockedScope(mutex);
+      mutex.assertCurrentThreadOwns();
+    }
+    mutex.assertNotCurrentThreadOwns();
+
+    // Free the wrapped mutex - we don't need it anymore.
+    sqlite3_mutex_free(inner);
+  }
+}
+
+TEST(storage_mutex, AutoUnlock)
+{
+  int lockTypes[] = {
+      SQLITE_MUTEX_FAST,
+      SQLITE_MUTEX_RECURSIVE,
+  };
+  for (int lockType : lockTypes) {
+    // Get our test mutex (we have to allocate a SQLite mutex of the right type
+    // too!).
+    SQLiteMutex mutex("TestMutex");
+    sqlite3_mutex* inner = sqlite3_mutex_alloc(lockType);
+    do_check_true(inner);
+    mutex.initWithMutex(inner);
+
+    // And test that our automatic unlocking wrapper works as expected.
+    {
+      SQLiteMutexAutoLock lockedScope(mutex);
+
+      {
+        SQLiteMutexAutoUnlock unlockedScope(mutex);
+        mutex.assertNotCurrentThreadOwns();
+      }
+      mutex.assertCurrentThreadOwns();
+    }
+
+    // Free the wrapped mutex - we don't need it anymore.
+    sqlite3_mutex_free(inner);
+  }
+}
diff --git a/storage/test/gtest/test_spinningSynchronousClose.cpp b/storage/test/gtest/test_spinningSynchronousClose.cpp
new file mode 100644
index 0000000000..81f9bee11a
--- /dev/null
+++ b/storage/test/gtest/test_spinningSynchronousClose.cpp
@@ -0,0 +1,72 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "storage_test_harness.h"
+#include "prinrval.h"
+
+using namespace mozilla;
+
+/**
+ * Helper to verify that the event loop was spun.  As long as this is dispatched
+ * prior to a call to Close()/SpinningSynchronousClose() we are guaranteed this
+ * will be run if the event loop is spun to perform a close.  This is because
+ * SpinningSynchronousClose must spin the event loop to realize the close
+ * completed and our runnable will already be enqueued and therefore run before
+ * the AsyncCloseConnection's callback.  Note that this invariant may be
+ * violated if our runnables end up in different queues thanks to Quantum
+ * changes, so this test may need to be updated if the close dispatch changes.
+ */
+class CompletionRunnable final : public Runnable {
+ public:
+  explicit CompletionRunnable()
+      : Runnable("CompletionRunnable"), mDone(false) {}
+
+  NS_IMETHOD Run() override {
+    mDone = true;
+    return NS_OK;
+  }
+
+  bool mDone;
+};
+
+// Can only run in optimized builds, or it would assert.
+#ifndef DEBUG
+TEST(storage_spinningSynchronousClose, CloseOnAsync)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+  // Run an async statement.
+  nsCOMPtr<mozIStorageAsyncStatement> stmt;
+  do_check_success(db->CreateAsyncStatement(
+      "CREATE TABLE test (id INTEGER PRIMARY KEY)"_ns, getter_AddRefs(stmt)));
+  nsCOMPtr<mozIStoragePendingStatement> p;
+  do_check_success(stmt->ExecuteAsync(nullptr, getter_AddRefs(p)));
+  do_check_success(stmt->Finalize());
+
+  // Wrongly use Close() instead of AsyncClose().
+  RefPtr<CompletionRunnable> event = new CompletionRunnable();
+  NS_DispatchToMainThread(event, NS_DISPATCH_NORMAL);
+  do_check_false(NS_SUCCEEDED(db->Close()));
+  do_check_true(event->mDone);
+}
+#endif
+
+TEST(storage_spinningSynchronousClose, spinningSynchronousCloseOnAsync)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+  // Run an async statement.
+  nsCOMPtr<mozIStorageAsyncStatement> stmt;
+  do_check_success(db->CreateAsyncStatement(
+      "CREATE TABLE test (id INTEGER PRIMARY KEY)"_ns, getter_AddRefs(stmt)));
+  nsCOMPtr<mozIStoragePendingStatement> p;
+  do_check_success(stmt->ExecuteAsync(nullptr, getter_AddRefs(p)));
+  do_check_success(stmt->Finalize());
+
+  // Use the spinning close API.
+  RefPtr<CompletionRunnable> event = new CompletionRunnable();
+  NS_DispatchToMainThread(event, NS_DISPATCH_NORMAL);
+  do_check_success(db->SpinningSynchronousClose());
+  do_check_true(event->mDone);
+}
diff --git a/storage/test/gtest/test_statement_scoper.cpp b/storage/test/gtest/test_statement_scoper.cpp
new file mode 100644
index 0000000000..3327b0ff6b
--- /dev/null
+++ b/storage/test/gtest/test_statement_scoper.cpp
@@ -0,0 +1,86 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "storage_test_harness.h"
+
+#include "mozStorageHelper.h"
+
+/**
+ * This file test our statement scoper in mozStorageHelper.h.
+ */
+
+TEST(storage_statement_scoper, automatic_reset)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // Need to create a table to populate sqlite_master with an entry.
+  (void)db->ExecuteSimpleSQL("CREATE TABLE test (id INTEGER PRIMARY KEY)"_ns);
+
+  nsCOMPtr<mozIStorageStatement> stmt;
+  (void)db->CreateStatement("SELECT * FROM sqlite_master"_ns,
+                            getter_AddRefs(stmt));
+
+  // Reality check - make sure we start off in the right state.
+  int32_t state = -1;
+  (void)stmt->GetState(&state);
+  do_check_true(state == mozIStorageStatement::MOZ_STORAGE_STATEMENT_READY);
+
+  // Start executing the statement, which will put it into an executing state.
+  {
+    mozStorageStatementScoper scoper(stmt);
+    bool hasMore;
+    do_check_true(NS_SUCCEEDED(stmt->ExecuteStep(&hasMore)));
+
+    // Reality check that we are executing.
+    state = -1;
+    (void)stmt->GetState(&state);
+    do_check_true(state ==
+                  mozIStorageStatement::MOZ_STORAGE_STATEMENT_EXECUTING);
+  }
+
+  // And we should be ready again.
+  state = -1;
+  (void)stmt->GetState(&state);
+  do_check_true(state == mozIStorageStatement::MOZ_STORAGE_STATEMENT_READY);
+}
+
+TEST(storage_statement_scoper, Abandon)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // Need to create a table to populate sqlite_master with an entry.
+  (void)db->ExecuteSimpleSQL("CREATE TABLE test (id INTEGER PRIMARY KEY)"_ns);
+
+  nsCOMPtr<mozIStorageStatement> stmt;
+  (void)db->CreateStatement("SELECT * FROM sqlite_master"_ns,
+                            getter_AddRefs(stmt));
+
+  // Reality check - make sure we start off in the right state.
+  int32_t state = -1;
+  (void)stmt->GetState(&state);
+  do_check_true(state == mozIStorageStatement::MOZ_STORAGE_STATEMENT_READY);
+
+  // Start executing the statement, which will put it into an executing state.
+  {
+    mozStorageStatementScoper scoper(stmt);
+    bool hasMore;
+    do_check_true(NS_SUCCEEDED(stmt->ExecuteStep(&hasMore)));
+
+    // Reality check that we are executing.
+    state = -1;
+    (void)stmt->GetState(&state);
+    do_check_true(state ==
+                  mozIStorageStatement::MOZ_STORAGE_STATEMENT_EXECUTING);
+
+    // And call Abandon.  We should not reset now when we fall out of scope.
+    scoper.Abandon();
+  }
+
+  // And we should still be executing.
+  state = -1;
+  (void)stmt->GetState(&state);
+  do_check_true(state == mozIStorageStatement::MOZ_STORAGE_STATEMENT_EXECUTING);
+}
diff --git a/storage/test/gtest/test_transaction_helper.cpp b/storage/test/gtest/test_transaction_helper.cpp
new file mode 100644
index 0000000000..d11f631967
--- /dev/null
+++ b/storage/test/gtest/test_transaction_helper.cpp
@@ -0,0 +1,184 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "storage_test_harness.h"
+
+#include "mozStorageHelper.h"
+#include "mozStorageConnection.h"
+
+using namespace mozilla;
+using namespace mozilla::storage;
+
+bool has_transaction(mozIStorageConnection* aDB) {
+  return !(static_cast<Connection*>(aDB)->getAutocommit());
+}
+
+/**
+ * This file tests our Transaction helper in mozStorageHelper.h.
+ */
+
+TEST(storage_transaction_helper, Commit)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // Create a table in a transaction, call Commit, and make sure that it does
+  // exists after the transaction falls out of scope.
+  {
+    mozStorageTransaction transaction(db, false);
+    do_check_success(transaction.Start());
+    do_check_true(has_transaction(db));
+    (void)db->ExecuteSimpleSQL("CREATE TABLE test (id INTEGER PRIMARY KEY)"_ns);
+    (void)transaction.Commit();
+  }
+  do_check_false(has_transaction(db));
+
+  bool exists = false;
+  (void)db->TableExists("test"_ns, &exists);
+  do_check_true(exists);
+}
+
+TEST(storage_transaction_helper, Rollback)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // Create a table in a transaction, call Rollback, and make sure that it does
+  // not exists after the transaction falls out of scope.
+  {
+    mozStorageTransaction transaction(db, true);
+    do_check_success(transaction.Start());
+    do_check_true(has_transaction(db));
+    (void)db->ExecuteSimpleSQL("CREATE TABLE test (id INTEGER PRIMARY KEY)"_ns);
+    (void)transaction.Rollback();
+  }
+  do_check_false(has_transaction(db));
+
+  bool exists = true;
+  (void)db->TableExists("test"_ns, &exists);
+  do_check_false(exists);
+}
+
+TEST(storage_transaction_helper, AutoCommit)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // Create a table in a transaction, and make sure that it exists after the
+  // transaction falls out of scope.  This means the Commit was successful.
+  {
+    mozStorageTransaction transaction(db, true);
+    do_check_success(transaction.Start());
+    do_check_true(has_transaction(db));
+    (void)db->ExecuteSimpleSQL("CREATE TABLE test (id INTEGER PRIMARY KEY)"_ns);
+  }
+  do_check_false(has_transaction(db));
+
+  bool exists = false;
+  (void)db->TableExists("test"_ns, &exists);
+  do_check_true(exists);
+}
+
+TEST(storage_transaction_helper, AutoRollback)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // Create a table in a transaction, and make sure that it does not exists
+  // after the transaction falls out of scope.  This means the Rollback was
+  // successful.
+  {
+    mozStorageTransaction transaction(db, false);
+    do_check_success(transaction.Start());
+    do_check_true(has_transaction(db));
+    (void)db->ExecuteSimpleSQL("CREATE TABLE test (id INTEGER PRIMARY KEY)"_ns);
+  }
+  do_check_false(has_transaction(db));
+
+  bool exists = true;
+  (void)db->TableExists("test"_ns, &exists);
+  do_check_false(exists);
+}
+
+TEST(storage_transaction_helper, null_database_connection)
+{
+  // We permit the use of the Transaction helper when passing a null database
+  // in, so we need to make sure this still works without crashing.
+  mozStorageTransaction transaction(nullptr, false);
+  do_check_success(transaction.Start());
+  do_check_true(NS_SUCCEEDED(transaction.Commit()));
+  do_check_true(NS_SUCCEEDED(transaction.Rollback()));
+}
+
+TEST(storage_transaction_helper, async_Commit)
+{
+  HookSqliteMutex hook;
+
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // -- wedge the thread
+  nsCOMPtr<nsIThread> target(get_conn_async_thread(db));
+  do_check_true(target);
+  RefPtr<ThreadWedger> wedger(new ThreadWedger(target));
+
+  {
+    mozStorageTransaction transaction(
+        db, false, mozIStorageConnection::TRANSACTION_DEFERRED, true);
+    do_check_success(transaction.Start());
+    do_check_true(has_transaction(db));
+    (void)db->ExecuteSimpleSQL("CREATE TABLE test (id INTEGER PRIMARY KEY)"_ns);
+    (void)transaction.Commit();
+  }
+  do_check_true(has_transaction(db));
+
+  // -- unwedge the async thread
+  wedger->unwedge();
+
+  // Ensure the transaction has done its job by enqueueing an async execution.
+  nsCOMPtr<mozIStorageAsyncStatement> stmt;
+  (void)db->CreateAsyncStatement("SELECT NULL"_ns, getter_AddRefs(stmt));
+  blocking_async_execute(stmt);
+  stmt->Finalize();
+  do_check_false(has_transaction(db));
+  bool exists = false;
+  (void)db->TableExists("test"_ns, &exists);
+  do_check_true(exists);
+
+  blocking_async_close(db);
+}
+
+TEST(storage_transaction_helper, Nesting)
+{
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  {
+    mozStorageTransaction transaction(db, false);
+    do_check_success(transaction.Start());
+    do_check_true(has_transaction(db));
+    do_check_success(
+        db->ExecuteSimpleSQL("CREATE TABLE test (id INTEGER PRIMARY KEY)"_ns));
+
+    {
+      mozStorageTransaction nestedTransaction(db, false);
+      do_check_success(nestedTransaction.Start());
+      do_check_true(has_transaction(db));
+      do_check_success(db->ExecuteSimpleSQL(
+          "CREATE TABLE nested_test (id INTEGER PRIMARY KEY)"_ns));
+
+#ifndef MOZ_DIAGNOSTIC_ASSERT_ENABLED
+      do_check_true(transaction.Commit() == NS_ERROR_NOT_AVAILABLE);
+      do_check_true(transaction.Rollback() == NS_ERROR_NOT_AVAILABLE);
+#endif
+    }
+
+    bool exists = false;
+    do_check_success(db->TableExists("nested_test"_ns, &exists));
+    do_check_false(exists);
+
+    (void)transaction.Commit();
+  }
+  do_check_false(has_transaction(db));
+
+  bool exists = false;
+  do_check_success(db->TableExists("test"_ns, &exists));
+  do_check_true(exists);
+}
diff --git a/storage/test/gtest/test_true_async.cpp b/storage/test/gtest/test_true_async.cpp
new file mode 100644
index 0000000000..3b54b73b3a
--- /dev/null
+++ b/storage/test/gtest/test_true_async.cpp
@@ -0,0 +1,161 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "storage_test_harness.h"
+
+////////////////////////////////////////////////////////////////////////////////
+//// Tests
+
+TEST(storage_true_async, TrueAsyncStatement)
+{
+  HookSqliteMutex hook;
+
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // Start watching for forbidden mutex usage.
+  watch_for_mutex_use_on_this_thread();
+
+  // - statement with nothing to bind
+  nsCOMPtr<mozIStorageAsyncStatement> stmt;
+  db->CreateAsyncStatement("CREATE TABLE test (id INTEGER PRIMARY KEY)"_ns,
+                           getter_AddRefs(stmt));
+  blocking_async_execute(stmt);
+  stmt->Finalize();
+  do_check_false(mutex_used_on_watched_thread);
+
+  // - statement with something to bind ordinally
+  db->CreateAsyncStatement("INSERT INTO test (id) VALUES (?)"_ns,
+                           getter_AddRefs(stmt));
+  stmt->BindInt32ByIndex(0, 1);
+  blocking_async_execute(stmt);
+  stmt->Finalize();
+  do_check_false(mutex_used_on_watched_thread);
+
+  // - statement with something to bind by name
+  db->CreateAsyncStatement("INSERT INTO test (id) VALUES (:id)"_ns,
+                           getter_AddRefs(stmt));
+  nsCOMPtr<mozIStorageBindingParamsArray> paramsArray;
+  stmt->NewBindingParamsArray(getter_AddRefs(paramsArray));
+  nsCOMPtr<mozIStorageBindingParams> params;
+  paramsArray->NewBindingParams(getter_AddRefs(params));
+  params->BindInt32ByName("id"_ns, 2);
+  paramsArray->AddParams(params);
+  params = nullptr;
+  stmt->BindParameters(paramsArray);
+  paramsArray = nullptr;
+  blocking_async_execute(stmt);
+  stmt->Finalize();
+  do_check_false(mutex_used_on_watched_thread);
+
+  // - now, make sure creating a sync statement does trigger our guard.
+  // (If this doesn't happen, our test is bunk and it's important to know that.)
+  nsCOMPtr<mozIStorageStatement> syncStmt;
+  db->CreateStatement("SELECT * FROM test"_ns, getter_AddRefs(syncStmt));
+  syncStmt->Finalize();
+  do_check_true(mutex_used_on_watched_thread);
+
+  blocking_async_close(db);
+}
+
+/**
+ * Test that cancellation before a statement is run successfully stops the
+ * statement from executing.
+ */
+TEST(storage_true_async, AsyncCancellation)
+{
+  HookSqliteMutex hook;
+
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+
+  // -- wedge the thread
+  nsCOMPtr<nsIThread> target(get_conn_async_thread(db));
+  do_check_true(target);
+  RefPtr<ThreadWedger> wedger(new ThreadWedger(target));
+
+  // -- create statements and cancel them
+  // - async
+  nsCOMPtr<mozIStorageAsyncStatement> asyncStmt;
+  db->CreateAsyncStatement(
+      "CREATE TABLE asyncTable (id INTEGER PRIMARY KEY)"_ns,
+      getter_AddRefs(asyncStmt));
+
+  RefPtr<AsyncStatementSpinner> asyncSpin(new AsyncStatementSpinner());
+  nsCOMPtr<mozIStoragePendingStatement> asyncPend;
+  (void)asyncStmt->ExecuteAsync(asyncSpin, getter_AddRefs(asyncPend));
+  do_check_true(asyncPend);
+  asyncPend->Cancel();
+
+  // - sync
+  nsCOMPtr<mozIStorageStatement> syncStmt;
+  db->CreateStatement("CREATE TABLE syncTable (id INTEGER PRIMARY KEY)"_ns,
+                      getter_AddRefs(syncStmt));
+
+  RefPtr<AsyncStatementSpinner> syncSpin(new AsyncStatementSpinner());
+  nsCOMPtr<mozIStoragePendingStatement> syncPend;
+  (void)syncStmt->ExecuteAsync(syncSpin, getter_AddRefs(syncPend));
+  do_check_true(syncPend);
+  syncPend->Cancel();
+
+  // -- unwedge the async thread
+  wedger->unwedge();
+
+  // -- verify that both statements report they were canceled
+  asyncSpin->SpinUntilCompleted();
+  do_check_true(asyncSpin->completionReason ==
+                mozIStorageStatementCallback::REASON_CANCELED);
+
+  syncSpin->SpinUntilCompleted();
+  do_check_true(syncSpin->completionReason ==
+                mozIStorageStatementCallback::REASON_CANCELED);
+
+  // -- verify that neither statement constructed their tables
+  nsresult rv;
+  bool exists;
+  rv = db->TableExists("asyncTable"_ns, &exists);
+  do_check_true(rv == NS_OK);
+  do_check_false(exists);
+  rv = db->TableExists("syncTable"_ns, &exists);
+  do_check_true(rv == NS_OK);
+  do_check_false(exists);
+
+  // -- cleanup
+  asyncStmt->Finalize();
+  syncStmt->Finalize();
+  blocking_async_close(db);
+}
+
+/**
+ * Test that the destructor for an asynchronous statement which has a
+ *  sqlite3_stmt will dispatch that statement to the async thread for
+ *  finalization rather than trying to finalize it on the main thread
+ *  (and thereby running afoul of our mutex use detector).
+ */
+TEST(storage_true_async, AsyncDestructorFinalizesOnAsyncThread)
+{
+  HookSqliteMutex hook;
+
+  nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());
+  watch_for_mutex_use_on_this_thread();
+
+  // -- create an async statement
+  nsCOMPtr<mozIStorageAsyncStatement> stmt;
+  db->CreateAsyncStatement("CREATE TABLE test (id INTEGER PRIMARY KEY)"_ns,
+                           getter_AddRefs(stmt));
+
+  // -- execute it so it gets a sqlite3_stmt that needs to be finalized
+  blocking_async_execute(stmt);
+  do_check_false(mutex_used_on_watched_thread);
+
+  // -- forget our reference
+  stmt = nullptr;
+
+  // -- verify the mutex was not touched
+  do_check_false(mutex_used_on_watched_thread);
+
+  // -- make sure the statement actually gets finalized / cleanup
+  // the close will assert if we failed to finalize!
+  blocking_async_close(db);
+}
diff --git a/storage/test/gtest/test_unlock_notify.cpp b/storage/test/gtest/test_unlock_notify.cpp
new file mode 100644
index 0000000000..93cc5b09a8
--- /dev/null
+++ b/storage/test/gtest/test_unlock_notify.cpp
@@ -0,0 +1,234 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim set:sw=2 ts=2 et lcs=trail\:.,tab\:>~ : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "storage_test_harness.h"
+
+#include "mozilla/ReentrantMonitor.h"
+#include "nsThreadUtils.h"
+#include "mozIStorageStatement.h"
+
+/**
+ * This file tests that our implementation around sqlite3_unlock_notify works
+ * as expected.
+ */
+
+////////////////////////////////////////////////////////////////////////////////
+//// Helpers
+
+enum State { STARTING, WRITE_LOCK, READ_LOCK, TEST_DONE };
+
+class DatabaseLocker : public mozilla::Runnable {
+ public:
+  explicit DatabaseLocker(const char* aSQL, nsIFile* aDBFile = nullptr)
+      : mozilla::Runnable("DatabaseLocker"),
+        monitor("DatabaseLocker::monitor"),
+        mSQL(aSQL),
+        mState(STARTING),
+        mDBFile(aDBFile) {}
+
+  void RunInBackground() {
+    (void)NS_NewNamedThread("DatabaseLocker", getter_AddRefs(mThread));
+    do_check_true(mThread);
+
+    do_check_success(mThread->Dispatch(this, NS_DISPATCH_NORMAL));
+  }
+
+  void Shutdown() {
+    if (mThread) {
+      mThread->Shutdown();
+    }
+  }
+
+  NS_IMETHOD Run() override {
+    mozilla::ReentrantMonitorAutoEnter lock(monitor);
+
+    nsCOMPtr<mozIStorageConnection> db(getDatabase(mDBFile));
+
+    nsCString sql(mSQL);
+    nsCOMPtr<mozIStorageStatement> stmt;
+    do_check_success(db->CreateStatement(sql, getter_AddRefs(stmt)));
+
+    bool hasResult;
+    do_check_success(stmt->ExecuteStep(&hasResult));
+
+    Notify(WRITE_LOCK);
+    WaitFor(TEST_DONE);
+
+    return NS_OK;
+  }
+
+  void WaitFor(State aState) {
+    monitor.AssertCurrentThreadIn();
+    while (mState != aState) {
+      do_check_success(monitor.Wait());
+    }
+  }
+
+  void Notify(State aState) {
+    monitor.AssertCurrentThreadIn();
+    mState = aState;
+    do_check_success(monitor.Notify());
+  }
+
+  mozilla::ReentrantMonitor monitor MOZ_UNANNOTATED;
+
+ protected:
+  nsCOMPtr<nsIThread> mThread;
+  const char* const mSQL;
+  State mState;
+  nsCOMPtr<nsIFile> mDBFile;
+};
+
+class DatabaseTester : public DatabaseLocker {
+ public:
+  DatabaseTester(mozIStorageConnection* aConnection, const char* aSQL)
+      : DatabaseLocker(aSQL), mConnection(aConnection) {}
+
+  NS_IMETHOD Run() override {
+    mozilla::ReentrantMonitorAutoEnter lock(monitor);
+    WaitFor(READ_LOCK);
+
+    nsCString sql(mSQL);
+    nsCOMPtr<mozIStorageStatement> stmt;
+    do_check_success(mConnection->CreateStatement(sql, getter_AddRefs(stmt)));
+
+    bool hasResult;
+    nsresult rv = stmt->ExecuteStep(&hasResult);
+    do_check_eq(rv, NS_ERROR_FILE_IS_LOCKED);
+
+    // Finalize our statement and null out our connection before notifying to
+    // ensure that we close on the proper thread.
+    rv = stmt->Finalize();
+    do_check_eq(rv, NS_ERROR_FILE_IS_LOCKED);
+    mConnection = nullptr;
+
+    Notify(TEST_DONE);
+
+    return NS_OK;
+  }
+
+ private:
+  nsCOMPtr<mozIStorageConnection> mConnection;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Test Functions
+
+void setup() {
+  nsCOMPtr<mozIStorageConnection> db(getDatabase());
+
+  // Create and populate a dummy table.
+  nsresult rv = db->ExecuteSimpleSQL(nsLiteralCString(
+      "CREATE TABLE test (id INTEGER PRIMARY KEY, data STRING)"));
+  do_check_success(rv);
+  rv = db->ExecuteSimpleSQL("INSERT INTO test (data) VALUES ('foo')"_ns);
+  do_check_success(rv);
+  rv = db->ExecuteSimpleSQL("INSERT INTO test (data) VALUES ('bar')"_ns);
+  do_check_success(rv);
+  rv =
+      db->ExecuteSimpleSQL("CREATE UNIQUE INDEX unique_data ON test (data)"_ns);
+  do_check_success(rv);
+}
+
+void test_step_locked_does_not_block_main_thread() {
+  nsCOMPtr<mozIStorageConnection> db(getDatabase());
+
+  // Need to prepare our statement ahead of time so we make sure to only test
+  // step and not prepare.
+  nsCOMPtr<mozIStorageStatement> stmt;
+  nsresult rv = db->CreateStatement(
+      "INSERT INTO test (data) VALUES ('test1')"_ns, getter_AddRefs(stmt));
+  do_check_success(rv);
+
+  nsCOMPtr<nsIFile> dbFile;
+  db->GetDatabaseFile(getter_AddRefs(dbFile));
+  RefPtr<DatabaseLocker> locker(
+      new DatabaseLocker("SELECT * FROM test", dbFile));
+  do_check_true(locker);
+  {
+    mozilla::ReentrantMonitorAutoEnter lock(locker->monitor);
+    locker->RunInBackground();
+
+    // Wait for the locker to notify us that it has locked the database
+    // properly.
+    locker->WaitFor(WRITE_LOCK);
+
+    bool hasResult;
+    rv = stmt->ExecuteStep(&hasResult);
+    do_check_eq(rv, NS_ERROR_FILE_IS_LOCKED);
+
+    locker->Notify(TEST_DONE);
+  }
+  locker->Shutdown();
+}
+
+void test_drop_index_does_not_loop() {
+  nsCOMPtr<mozIStorageConnection> db(getDatabase());
+
+  // Need to prepare our statement ahead of time so we make sure to only test
+  // step and not prepare.
+  nsCOMPtr<mozIStorageStatement> stmt;
+  nsresult rv =
+      db->CreateStatement("SELECT * FROM test"_ns, getter_AddRefs(stmt));
+  do_check_success(rv);
+
+  RefPtr<DatabaseTester> tester =
+      new DatabaseTester(db, "DROP INDEX unique_data");
+  do_check_true(tester);
+  {
+    mozilla::ReentrantMonitorAutoEnter lock(tester->monitor);
+    tester->RunInBackground();
+
+    // Hold a read lock on the database, and then let the tester try to execute.
+    bool hasResult;
+    rv = stmt->ExecuteStep(&hasResult);
+    do_check_success(rv);
+    do_check_true(hasResult);
+    tester->Notify(READ_LOCK);
+
+    // Make sure the tester finishes its test before we move on.
+    tester->WaitFor(TEST_DONE);
+  }
+  tester->Shutdown();
+}
+
+void test_drop_table_does_not_loop() {
+  nsCOMPtr<mozIStorageConnection> db(getDatabase());
+
+  // Need to prepare our statement ahead of time so we make sure to only test
+  // step and not prepare.
+  nsCOMPtr<mozIStorageStatement> stmt;
+  nsresult rv =
+      db->CreateStatement("SELECT * FROM test"_ns, getter_AddRefs(stmt));
+  do_check_success(rv);
+
+  RefPtr<DatabaseTester> tester(new DatabaseTester(db, "DROP TABLE test"));
+  do_check_true(tester);
+  {
+    mozilla::ReentrantMonitorAutoEnter lock(tester->monitor);
+    tester->RunInBackground();
+
+    // Hold a read lock on the database, and then let the tester try to execute.
+    bool hasResult;
+    rv = stmt->ExecuteStep(&hasResult);
+    do_check_success(rv);
+    do_check_true(hasResult);
+    tester->Notify(READ_LOCK);
+
+    // Make sure the tester finishes its test before we move on.
+    tester->WaitFor(TEST_DONE);
+  }
+  tester->Shutdown();
+}
+
+TEST(storage_unlock_notify, Test)
+{
+  // These must execute in order.
+  setup();
+  test_step_locked_does_not_block_main_thread();
+  test_drop_index_does_not_loop();
+  test_drop_table_does_not_loop();
+}
diff --git a/storage/test/moz.build b/storage/test/moz.build
new file mode 100644
index 0000000000..7dd21f5fe2
--- /dev/null
+++ b/storage/test/moz.build
@@ -0,0 +1,13 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+XPCSHELL_TESTS_MANIFESTS += ["unit/xpcshell.toml"]
+
+TEST_DIRS += ["gtest"]
+
+TESTING_JS_MODULES += [
+    "unit/VacuumParticipant.sys.mjs",
+]
diff --git a/storage/test/unit/VacuumParticipant.sys.mjs b/storage/test/unit/VacuumParticipant.sys.mjs
new file mode 100644
index 0000000000..9f1c39826e
--- /dev/null
+++ b/storage/test/unit/VacuumParticipant.sys.mjs
@@ -0,0 +1,109 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+// This testing component is used in test_vacuum* tests.
+
+const CAT_NAME = "vacuum-participant";
+const CONTRACT_ID = "@unit.test.com/test-vacuum-participant;1";
+
+import { MockRegistrar } from "resource://testing-common/MockRegistrar.sys.mjs";
+import { TestUtils } from "resource://testing-common/TestUtils.sys.mjs";
+
+export class VacuumParticipant {
+  #dbConn;
+  #expectedPageSize = 0;
+  #useIncrementalVacuum = false;
+  #grant = false;
+
+  /**
+   * Build a VacuumParticipant instance.
+   * Note: After creation you must await instance.promiseRegistered() to ensure
+   * Category Caches have been updated.
+   *
+   * @param {mozIStorageAsyncConnection} databaseConnection
+   *   The connection to be vacuumed.
+   * @param {Number} [expectedPageSize]
+   *   Used to change the database page size.
+   * @param {boolean} [useIncrementalVacuum]
+   *   Whether to enable incremental vacuum on the database.
+   * @param {boolean} [grant]
+   *   Whether the vacuum operation should be granted.
+   */
+  constructor(
+    databaseConnection,
+    { expectedPageSize = 0, useIncrementalVacuum = false, grant = true } = {}
+  ) {
+    this.#dbConn = databaseConnection;
+
+    // Register as the only participant.
+    this.#unregisterAllParticipants();
+    this.#registerAsParticipant();
+
+    this.#expectedPageSize = expectedPageSize;
+    this.#useIncrementalVacuum = useIncrementalVacuum;
+    this.#grant = grant;
+
+    this.QueryInterface = ChromeUtils.generateQI([
+      "mozIStorageVacuumParticipant",
+    ]);
+  }
+
+  promiseRegistered() {
+    // The category manager dispatches change notifications to the main thread,
+    // so we must wait one tick.
+    return TestUtils.waitForTick();
+  }
+
+  #registerAsParticipant() {
+    MockRegistrar.register(CONTRACT_ID, this);
+    Services.catMan.addCategoryEntry(
+      CAT_NAME,
+      "vacuumParticipant",
+      CONTRACT_ID,
+      false,
+      false
+    );
+  }
+
+  #unregisterAllParticipants() {
+    // First unregister other participants.
+    for (let { data: entry } of Services.catMan.enumerateCategory(CAT_NAME)) {
+      Services.catMan.deleteCategoryEntry("vacuum-participant", entry, false);
+    }
+  }
+
+  async dispose() {
+    this.#unregisterAllParticipants();
+    MockRegistrar.unregister(CONTRACT_ID);
+    await new Promise(resolve => {
+      this.#dbConn.asyncClose(resolve);
+    });
+  }
+
+  get expectedDatabasePageSize() {
+    return this.#expectedPageSize;
+  }
+
+  get useIncrementalVacuum() {
+    return this.#useIncrementalVacuum;
+  }
+
+  get databaseConnection() {
+    return this.#dbConn;
+  }
+
+  onBeginVacuum() {
+    if (!this.#grant) {
+      return false;
+    }
+    Services.obs.notifyObservers(null, "test-begin-vacuum");
+    return true;
+  }
+  onEndVacuum(succeeded) {
+    Services.obs.notifyObservers(
+      null,
+      succeeded ? "test-end-vacuum-success" : "test-end-vacuum-failure"
+    );
+  }
+}
diff --git a/storage/test/unit/baddataDB.sqlite b/storage/test/unit/baddataDB.sqlite
new file mode 100644
index 0000000000..5b2f9da3d6
--- /dev/null
+++ b/storage/test/unit/baddataDB.sqlite
diff --git a/storage/test/unit/corruptDB.sqlite b/storage/test/unit/corruptDB.sqlite
new file mode 100644
index 0000000000..b234246cac
--- /dev/null
+++ b/storage/test/unit/corruptDB.sqlite
diff --git a/storage/test/unit/fakeDB.sqlite b/storage/test/unit/fakeDB.sqlite
new file mode 100644
index 0000000000..5f7498bfc2
--- /dev/null
+++ b/storage/test/unit/fakeDB.sqlite
@@ -0,0 +1 @@
+BACON
diff --git a/storage/test/unit/goodDB.sqlite b/storage/test/unit/goodDB.sqlite
new file mode 100644
index 0000000000..b06884672f
--- /dev/null
+++ b/storage/test/unit/goodDB.sqlite
diff --git a/storage/test/unit/head_storage.js b/storage/test/unit/head_storage.js
new file mode 100644
index 0000000000..ba1b76ad0b
--- /dev/null
+++ b/storage/test/unit/head_storage.js
@@ -0,0 +1,412 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var { XPCOMUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/XPCOMUtils.sys.mjs"
+);
+var { AppConstants } = ChromeUtils.importESModule(
+  "resource://gre/modules/AppConstants.sys.mjs"
+);
+
+ChromeUtils.defineESModuleGetters(this, {
+  FileUtils: "resource://gre/modules/FileUtils.sys.mjs",
+  Sqlite: "resource://gre/modules/Sqlite.sys.mjs",
+  TelemetryTestUtils: "resource://testing-common/TelemetryTestUtils.sys.mjs",
+  TestUtils: "resource://testing-common/TestUtils.sys.mjs",
+});
+
+const OPEN_HISTOGRAM = "SQLITE_STORE_OPEN";
+const QUERY_HISTOGRAM = "SQLITE_STORE_QUERY";
+
+const TELEMETRY_VALUES = {
+  success: 0,
+  failure: 1,
+  access: 2,
+  diskio: 3,
+  corrupt: 4,
+  busy: 5,
+  misuse: 6,
+  diskspace: 7,
+};
+
+do_get_profile();
+var gDBConn = null;
+
+const TEST_DB_NAME = "test_storage.sqlite";
+function getTestDB() {
+  var db = Services.dirsvc.get("ProfD", Ci.nsIFile);
+  db.append(TEST_DB_NAME);
+  return db;
+}
+
+/**
+ * Obtains a corrupt database to test against.
+ */
+function getCorruptDB() {
+  return do_get_file("corruptDB.sqlite");
+}
+
+/**
+ * Obtains a fake (non-SQLite format) database to test against.
+ */
+function getFakeDB() {
+  return do_get_file("fakeDB.sqlite");
+}
+
+/**
+ * Delete the test database file.
+ */
+function deleteTestDB() {
+  print("*** Storage Tests: Trying to remove file!");
+  var dbFile = getTestDB();
+  if (dbFile.exists()) {
+    try {
+      dbFile.remove(false);
+    } catch (e) {
+      /* stupid windows box */
+    }
+  }
+}
+
+function cleanup() {
+  // close the connection
+  print("*** Storage Tests: Trying to close!");
+  getOpenedDatabase().close();
+
+  // we need to null out the database variable to get a new connection the next
+  // time getOpenedDatabase is called
+  gDBConn = null;
+
+  // removing test db
+  deleteTestDB();
+}
+
+/**
+ * Use asyncClose to cleanup a connection.  Synchronous by means of internally
+ * spinning an event loop.
+ */
+function asyncCleanup() {
+  let closed = false;
+
+  // close the connection
+  print("*** Storage Tests: Trying to asyncClose!");
+  getOpenedDatabase().asyncClose(function () {
+    closed = true;
+  });
+
+  let tm = Cc["@mozilla.org/thread-manager;1"].getService();
+  tm.spinEventLoopUntil("Test(head_storage.js:asyncCleanup)", () => closed);
+
+  // we need to null out the database variable to get a new connection the next
+  // time getOpenedDatabase is called
+  gDBConn = null;
+
+  // removing test db
+  deleteTestDB();
+}
+
+/**
+ * Get a connection to the test database.  Creates and caches the connection
+ * if necessary, otherwise reuses the existing cached connection. This
+ * connection shares its cache.
+ *
+ * @returns the mozIStorageConnection for the file.
+ */
+function getOpenedDatabase(connectionFlags = 0) {
+  if (!gDBConn) {
+    gDBConn = Services.storage.openDatabase(getTestDB(), connectionFlags);
+
+    // Clear out counts for any queries that occured while opening the database.
+    TelemetryTestUtils.getAndClearKeyedHistogram(OPEN_HISTOGRAM);
+    TelemetryTestUtils.getAndClearKeyedHistogram(QUERY_HISTOGRAM);
+  }
+  return gDBConn;
+}
+
+/**
+ * Get a connection to the test database.  Creates and caches the connection
+ * if necessary, otherwise reuses the existing cached connection. This
+ * connection doesn't share its cache.
+ *
+ * @returns the mozIStorageConnection for the file.
+ */
+function getOpenedUnsharedDatabase() {
+  if (!gDBConn) {
+    gDBConn = Services.storage.openUnsharedDatabase(getTestDB());
+  }
+  return gDBConn;
+}
+
+/**
+ * Obtains a specific database to use.
+ *
+ * @param aFile
+ *        The nsIFile representing the db file to open.
+ * @returns the mozIStorageConnection for the file.
+ */
+function getDatabase(aFile) {
+  return Services.storage.openDatabase(aFile);
+}
+
+function createStatement(aSQL) {
+  return getOpenedDatabase().createStatement(aSQL);
+}
+
+/**
+ * Creates an asynchronous SQL statement.
+ *
+ * @param aSQL
+ *        The SQL to parse into a statement.
+ * @returns a mozIStorageAsyncStatement from aSQL.
+ */
+function createAsyncStatement(aSQL) {
+  return getOpenedDatabase().createAsyncStatement(aSQL);
+}
+
+/**
+ * Invoke the given function and assert that it throws an exception expressing
+ * the provided error code in its 'result' attribute.  JS function expressions
+ * can be used to do this concisely.
+ *
+ * Example:
+ *  expectError(Cr.NS_ERROR_INVALID_ARG, () => explodingFunction());
+ *
+ * @param aErrorCode
+ *        The error code to expect from invocation of aFunction.
+ * @param aFunction
+ *        The function to invoke and expect an XPCOM-style error from.
+ */
+function expectError(aErrorCode, aFunction) {
+  let exceptionCaught = false;
+  try {
+    aFunction();
+  } catch (e) {
+    if (e.result != aErrorCode) {
+      do_throw(
+        "Got an exception, but the result code was not the expected " +
+          "one.  Expected " +
+          aErrorCode +
+          ", got " +
+          e.result
+      );
+    }
+    exceptionCaught = true;
+  }
+  if (!exceptionCaught) {
+    do_throw(aFunction + " should have thrown an exception but did not!");
+  }
+}
+
+/**
+ * Run a query synchronously and verify that we get back the expected results.
+ *
+ * @param aSQLString
+ *        The SQL string for the query.
+ * @param aBind
+ *        The value to bind at index 0.
+ * @param aResults
+ *        A list of the expected values returned in the sole result row.
+ *        Express blobs as lists.
+ */
+function verifyQuery(aSQLString, aBind, aResults) {
+  let stmt = getOpenedDatabase().createStatement(aSQLString);
+  stmt.bindByIndex(0, aBind);
+  try {
+    Assert.ok(stmt.executeStep());
+    let nCols = stmt.numEntries;
+    if (aResults.length != nCols) {
+      do_throw(
+        "Expected " +
+          aResults.length +
+          " columns in result but " +
+          "there are only " +
+          aResults.length +
+          "!"
+      );
+    }
+    for (let iCol = 0; iCol < nCols; iCol++) {
+      let expectedVal = aResults[iCol];
+      let valType = stmt.getTypeOfIndex(iCol);
+      if (expectedVal === null) {
+        Assert.equal(stmt.VALUE_TYPE_NULL, valType);
+        Assert.ok(stmt.getIsNull(iCol));
+      } else if (typeof expectedVal == "number") {
+        if (Math.floor(expectedVal) == expectedVal) {
+          Assert.equal(stmt.VALUE_TYPE_INTEGER, valType);
+          Assert.equal(expectedVal, stmt.getInt32(iCol));
+        } else {
+          Assert.equal(stmt.VALUE_TYPE_FLOAT, valType);
+          Assert.equal(expectedVal, stmt.getDouble(iCol));
+        }
+      } else if (typeof expectedVal == "string") {
+        Assert.equal(stmt.VALUE_TYPE_TEXT, valType);
+        Assert.equal(expectedVal, stmt.getUTF8String(iCol));
+      } else {
+        // blob
+        Assert.equal(stmt.VALUE_TYPE_BLOB, valType);
+        let count = { value: 0 },
+          blob = { value: null };
+        stmt.getBlob(iCol, count, blob);
+        Assert.equal(count.value, expectedVal.length);
+        for (let i = 0; i < count.value; i++) {
+          Assert.equal(expectedVal[i], blob.value[i]);
+        }
+      }
+    }
+  } finally {
+    stmt.finalize();
+  }
+}
+
+/**
+ * Return the number of rows in the able with the given name using a synchronous
+ * query.
+ *
+ * @param aTableName
+ *        The name of the table.
+ * @return The number of rows.
+ */
+function getTableRowCount(aTableName) {
+  var currentRows = 0;
+  var countStmt = getOpenedDatabase().createStatement(
+    "SELECT COUNT(1) AS count FROM " + aTableName
+  );
+  try {
+    Assert.ok(countStmt.executeStep());
+    currentRows = countStmt.row.count;
+  } finally {
+    countStmt.finalize();
+  }
+  return currentRows;
+}
+
+// Promise-Returning Functions
+
+function asyncClone(db, readOnly) {
+  return new Promise((resolve, reject) => {
+    db.asyncClone(readOnly, function (status, db2) {
+      if (Components.isSuccessCode(status)) {
+        resolve(db2.QueryInterface(Ci.mozIStorageAsyncConnection));
+      } else {
+        reject(status);
+      }
+    });
+  });
+}
+
+function asyncClose(db) {
+  return new Promise((resolve, reject) => {
+    db.asyncClose(function (status) {
+      if (Components.isSuccessCode(status)) {
+        resolve();
+      } else {
+        reject(status);
+      }
+    });
+  });
+}
+
+function mapOptionsToFlags(aOptions, aMapping) {
+  let result = aMapping.default;
+  Object.entries(aOptions || {}).forEach(([optionName, isTrue]) => {
+    if (aMapping.hasOwnProperty(optionName) && isTrue) {
+      result |= aMapping[optionName];
+    }
+  });
+  return result;
+}
+
+function getOpenFlagsMap() {
+  return {
+    default: Ci.mozIStorageService.OPEN_DEFAULT,
+    shared: Ci.mozIStorageService.OPEN_SHARED,
+    readOnly: Ci.mozIStorageService.OPEN_READONLY,
+    ignoreLockingMode: Ci.mozIStorageService.OPEN_IGNORE_LOCKING_MODE,
+  };
+}
+
+function getConnectionFlagsMap() {
+  return {
+    default: Ci.mozIStorageService.CONNECTION_DEFAULT,
+    interruptible: Ci.mozIStorageService.CONNECTION_INTERRUPTIBLE,
+  };
+}
+
+function openAsyncDatabase(file, options) {
+  return new Promise((resolve, reject) => {
+    const openFlags = mapOptionsToFlags(options, getOpenFlagsMap());
+    const connectionFlags = mapOptionsToFlags(options, getConnectionFlagsMap());
+
+    Services.storage.openAsyncDatabase(
+      file,
+      openFlags,
+      connectionFlags,
+      function (status, db) {
+        if (Components.isSuccessCode(status)) {
+          resolve(db.QueryInterface(Ci.mozIStorageAsyncConnection));
+        } else {
+          reject(status);
+        }
+      }
+    );
+  });
+}
+
+function executeAsync(statement, onResult) {
+  return new Promise((resolve, reject) => {
+    statement.executeAsync({
+      handleError(error) {
+        reject(error);
+      },
+      handleResult(result) {
+        if (onResult) {
+          onResult(result);
+        }
+      },
+      handleCompletion(result) {
+        resolve(result);
+      },
+    });
+  });
+}
+
+function executeMultipleStatementsAsync(db, statements, onResult) {
+  return new Promise((resolve, reject) => {
+    db.executeAsync(statements, {
+      handleError(error) {
+        reject(error);
+      },
+      handleResult(result) {
+        if (onResult) {
+          onResult(result);
+        }
+      },
+      handleCompletion(result) {
+        resolve(result);
+      },
+    });
+  });
+}
+
+function executeSimpleSQLAsync(db, query, onResult) {
+  return new Promise((resolve, reject) => {
+    db.executeSimpleSQLAsync(query, {
+      handleError(error) {
+        reject(error);
+      },
+      handleResult(result) {
+        if (onResult) {
+          onResult(result);
+        } else {
+          do_throw("No results were expected");
+        }
+      },
+      handleCompletion(result) {
+        resolve(result);
+      },
+    });
+  });
+}
+
+cleanup();
diff --git a/storage/test/unit/locale_collation.txt b/storage/test/unit/locale_collation.txt
new file mode 100644
index 0000000000..86f50579bb
--- /dev/null
+++ b/storage/test/unit/locale_collation.txt
@@ -0,0 +1,174 @@
+ 
+!
+"
+#
+$
+%
+&
+'
+(
+)
+*
++
+,
+-
+.
+/
+0
+1
+2
+3
+4
+5
+6
+7
+8
+9
+:
+;
+<
+=
+>
+?
+@
+A
+B
+C
+D
+E
+F
+G
+H
+I
+J
+K
+L
+M
+N
+O
+P
+Q
+R
+S
+T
+U
+V
+W
+X
+Y
+Z
+[
+\
+]
+^
+_
+`
+a
+b
+c
+d
+e
+f
+g
+h
+i
+j
+k
+l
+m
+n
+o
+p
+q
+r
+s
+t
+u
+v
+w
+x
+y
+z
+{
+|
+}
+~
+ludwig van beethoven
+Ludwig van Beethoven
+Ludwig van beethoven
+Jane
+jane
+JANE
+jAne
+jaNe
+janE
+JAne
+JaNe
+JanE
+JANe
+JaNE
+JAnE
+jANE
+Umberto Eco
+Umberto eco
+umberto eco
+umberto Eco
+UMBERTO ECO
+ace
+bash
+*ace
+!ace
+%ace
+~ace
+#ace
+cork
+denizen
+[denizen]
+(denizen)
+{denizen}
+/denizen/
+#denizen#
+$denizen$
+@denizen
+elf
+full
+gnome
+gnomic investigation of typological factors in the grammaticalization process of Malayo-Polynesian substaratum in the protoAltaic vocabulary core in the proto-layers of pre-historic Japanese
+gnomic investigation of typological factors in the grammaticalization process of Malayo-Polynesian substaratum in the protoAltaic vocabulary core in the proto-layers of pre-historic Javanese
+hint
+Internationalization
+Zinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalization
+Zinternationalization internationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizatio
+n
+Zinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalization internationalizationinternationalizationinternationalizationinternationalizationinternationalization
+ZinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizaTioninternationalizationinternationalizationinternationalizationinternationalization
+ZinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizationinternationalizaTion
+jostle
+kin
+Laymen
+lumens
+Lumens
+motleycrew
+motley crew
+niven's creative talents
+nivens creative talents
+opie
+posh restaurants in surbanized and still urban incorporated subsection of this beautifl city in the Rockies
+posh restaurants in surbanized and still urban incorporated subsection of this beautifl city in the Rokkies
+posh restaurants in surbanized and still urban incorporated subsection of this beautifl city in the rockies
+quilt's
+quilts
+quilt
+Rondo
+street
+tamale oxidization and iodization in rapid progress
+tamale oxidization and iodization in rapid Progress
+until
+vera
+Wobble
+Xanadu's legenary imaginary floccinaucinihilipilification in localization of theoretical portions of glottochronological understanding of the phoneme
+Xanadu's legenary imaginary floccinaucinihilipilification in localization of theoretical portions of glottochronological understanding of the phoname
+yearn
+zodiac
+a
+å
diff --git a/storage/test/unit/test_bug-365166.js b/storage/test/unit/test_bug-365166.js
new file mode 100644
index 0000000000..aef53e60f2
--- /dev/null
+++ b/storage/test/unit/test_bug-365166.js
@@ -0,0 +1,23 @@
+// Testcase for bug 365166 - crash [@ strlen] calling
+// mozIStorageStatement::getColumnName of a statement created with
+// "PRAGMA user_version" or "PRAGMA schema_version"
+function run_test() {
+  test("user");
+  test("schema");
+
+  function test(param) {
+    var colName = param + "_version";
+    var sql = "PRAGMA " + colName;
+
+    var file = getTestDB();
+    var conn = Services.storage.openDatabase(file);
+    var statement = conn.createStatement(sql);
+    try {
+      // This shouldn't crash:
+      Assert.equal(statement.getColumnName(0), colName);
+    } finally {
+      statement.reset();
+      statement.finalize();
+    }
+  }
+}
diff --git a/storage/test/unit/test_bug-393952.js b/storage/test/unit/test_bug-393952.js
new file mode 100644
index 0000000000..a91bcb034e
--- /dev/null
+++ b/storage/test/unit/test_bug-393952.js
@@ -0,0 +1,35 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Testcase for bug 393952:  crash when I try to VACUUM and one of the tables
+// has a UNIQUE text column.   StorageUnicodeFunctions::likeFunction()
+// needs to handle null aArgv[0] and aArgv[1]
+
+function setup() {
+  getOpenedDatabase().createTable("t1", "x TEXT UNIQUE");
+
+  var stmt = createStatement("INSERT INTO t1 (x) VALUES ('a')");
+  stmt.execute();
+  stmt.reset();
+  stmt.finalize();
+}
+
+function test_vacuum() {
+  var stmt = createStatement("VACUUM;");
+  stmt.executeStep();
+  stmt.reset();
+  stmt.finalize();
+}
+
+var tests = [test_vacuum];
+
+function run_test() {
+  setup();
+
+  for (var i = 0; i < tests.length; i++) {
+    tests[i]();
+  }
+
+  cleanup();
+}
diff --git a/storage/test/unit/test_bug-429521.js b/storage/test/unit/test_bug-429521.js
new file mode 100644
index 0000000000..1e647e984a
--- /dev/null
+++ b/storage/test/unit/test_bug-429521.js
@@ -0,0 +1,49 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function setup() {
+  getOpenedDatabase().createTable("t1", "x TEXT");
+
+  var stmt = createStatement(
+    "INSERT INTO t1 (x) VALUES ('/mozilla.org/20070129_1/Europe/Berlin')"
+  );
+  stmt.execute();
+  stmt.finalize();
+}
+
+function test_bug429521() {
+  var stmt = createStatement(
+    "SELECT DISTINCT(zone) FROM (" +
+      "SELECT x AS zone FROM t1 WHERE x LIKE '/mozilla.org%'" +
+      ");"
+  );
+
+  print("*** test_bug429521: started");
+
+  try {
+    while (stmt.executeStep()) {
+      print("*** test_bug429521: step() Read wrapper.row.zone");
+
+      // BUG: the print commands after the following statement
+      // are never executed. Script stops immediately.
+      stmt.row.zone;
+
+      print("*** test_bug429521: step() Read wrapper.row.zone finished");
+    }
+  } catch (e) {
+    print("*** test_bug429521: " + e);
+  }
+
+  print("*** test_bug429521: finished");
+
+  stmt.finalize();
+}
+
+function run_test() {
+  setup();
+
+  test_bug429521();
+
+  cleanup();
+}
diff --git a/storage/test/unit/test_bug-444233.js b/storage/test/unit/test_bug-444233.js
new file mode 100644
index 0000000000..934f69ad60
--- /dev/null
+++ b/storage/test/unit/test_bug-444233.js
@@ -0,0 +1,54 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function setup() {
+  // Create the table
+  getOpenedDatabase().createTable(
+    "test_bug444233",
+    "id INTEGER PRIMARY KEY, value TEXT"
+  );
+
+  // Insert dummy data, using wrapper methods
+  var stmt = createStatement(
+    "INSERT INTO test_bug444233 (value) VALUES (:value)"
+  );
+  stmt.params.value = "value1";
+  stmt.execute();
+  stmt.finalize();
+
+  stmt = createStatement("INSERT INTO test_bug444233 (value) VALUES (:value)");
+  stmt.params.value = "value2";
+  stmt.execute();
+  stmt.finalize();
+}
+
+function test_bug444233() {
+  print("*** test_bug444233: started");
+
+  // Check that there are 2 results
+  var stmt = createStatement("SELECT COUNT(*) AS number FROM test_bug444233");
+  Assert.ok(stmt.executeStep());
+  Assert.equal(2, stmt.row.number);
+  stmt.reset();
+  stmt.finalize();
+
+  print("*** test_bug444233: doing delete");
+
+  // Now try to delete using IN
+  // Cheating since we know ids are 1,2
+  try {
+    var ids = [1, 2];
+    stmt = createStatement("DELETE FROM test_bug444233 WHERE id IN (:ids)");
+    stmt.params.ids = ids;
+  } catch (e) {
+    print("*** test_bug444233: successfully caught exception");
+  }
+  stmt.finalize();
+}
+
+function run_test() {
+  setup();
+  test_bug444233();
+  cleanup();
+}
diff --git a/storage/test/unit/test_cache_size.js b/storage/test/unit/test_cache_size.js
new file mode 100644
index 0000000000..bd56de64cd
--- /dev/null
+++ b/storage/test/unit/test_cache_size.js
@@ -0,0 +1,73 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// This file tests that dbs of various page sizes are using the right cache
+// size (bug 703113).
+
+/**
+ * In order to change the cache size, we must open a DB, change the page
+ * size, create a table, close the DB, then re-open the DB.  We then check
+ * the cache size after reopening.
+ *
+ * @param dbOpener
+ *        function that opens the DB specified in file
+ * @param file
+ *        file holding the database
+ * @param pageSize
+ *        the DB's page size
+ * @param expectedCacheSize
+ *        the expected cache size for the given page size
+ */
+function check_size(dbOpener, file, pageSize, expectedCacheSize) {
+  // Open the DB, immediately change its page size.
+  let db = dbOpener(file);
+  db.executeSimpleSQL("PRAGMA page_size = " + pageSize);
+
+  // Check the page size change worked.
+  let stmt = db.createStatement("PRAGMA page_size");
+  Assert.ok(stmt.executeStep());
+  Assert.equal(stmt.row.page_size, pageSize);
+  stmt.finalize();
+
+  // Create a simple table.
+  db.executeSimpleSQL("CREATE TABLE test ( id INTEGER PRIMARY KEY )");
+
+  // Close and re-open the DB.
+  db.close();
+  db = dbOpener(file);
+
+  // Check cache size is as expected.
+  stmt = db.createStatement("PRAGMA cache_size");
+  Assert.ok(stmt.executeStep());
+  Assert.equal(stmt.row.cache_size, expectedCacheSize);
+  stmt.finalize();
+}
+
+function new_file(name) {
+  let file = Services.dirsvc.get("ProfD", Ci.nsIFile);
+  file.append(name + ".sqlite");
+  Assert.ok(!file.exists());
+  return file;
+}
+
+function run_test() {
+  const kExpectedCacheSize = -2048; // 2MiB
+
+  let pageSizes = [1024, 4096, 32768];
+
+  for (let i = 0; i < pageSizes.length; i++) {
+    let pageSize = pageSizes[i];
+    check_size(
+      getDatabase,
+      new_file("shared" + pageSize),
+      pageSize,
+      kExpectedCacheSize
+    );
+    check_size(
+      Services.storage.openUnsharedDatabase,
+      new_file("unshared" + pageSize),
+      pageSize,
+      kExpectedCacheSize
+    );
+  }
+}
diff --git a/storage/test/unit/test_chunk_growth.js b/storage/test/unit/test_chunk_growth.js
new file mode 100644
index 0000000000..4bcdf86ce3
--- /dev/null
+++ b/storage/test/unit/test_chunk_growth.js
@@ -0,0 +1,51 @@
+// This file tests SQLITE_FCNTL_CHUNK_SIZE behaves as expected
+
+function run_sql(d, sql) {
+  var stmt = d.createStatement(sql);
+  stmt.execute();
+  stmt.finalize();
+}
+
+function new_file(name) {
+  var file = Services.dirsvc.get("ProfD", Ci.nsIFile);
+  file.append(name);
+  return file;
+}
+
+function get_size(name) {
+  return new_file(name).fileSize;
+}
+
+function run_test() {
+  const filename = "chunked.sqlite";
+  const CHUNK_SIZE = 512 * 1024;
+  var d = getDatabase(new_file(filename));
+  try {
+    d.setGrowthIncrement(CHUNK_SIZE, "");
+  } catch (e) {
+    if (e.result != Cr.NS_ERROR_FILE_TOO_BIG) {
+      throw e;
+    }
+    print("Too little free space to set CHUNK_SIZE!");
+    return;
+  }
+  run_sql(d, "CREATE TABLE bloat(data varchar)");
+
+  var orig_size = get_size(filename);
+  /* Dump in at least 32K worth of data.
+   * While writing ensure that the file size growth in chunksize set above.
+   */
+  const str1024 = new Array(1024).join("T");
+  for (var i = 0; i < 32; i++) {
+    run_sql(d, "INSERT INTO bloat VALUES('" + str1024 + "')");
+    var size = get_size(filename);
+    // Must not grow in small increments.
+    Assert.ok(size == orig_size || size >= CHUNK_SIZE);
+  }
+  /* In addition to growing in chunk-size increments, the db
+   * should shrink in chunk-size increments too.
+   */
+  run_sql(d, "DELETE FROM bloat");
+  run_sql(d, "VACUUM");
+  Assert.ok(get_size(filename) >= CHUNK_SIZE);
+}
diff --git a/storage/test/unit/test_connection_asyncClose.js b/storage/test/unit/test_connection_asyncClose.js
new file mode 100644
index 0000000000..2d89087c5c
--- /dev/null
+++ b/storage/test/unit/test_connection_asyncClose.js
@@ -0,0 +1,128 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Thorough branch coverage for asyncClose.
+ *
+ * Coverage of asyncClose by connection state at time of AsyncClose invocation:
+ * - (asyncThread && mDBConn) => AsyncCloseConnection used, actually closes
+ *   - test_asyncClose_does_not_complete_before_statements
+ *   - test_double_asyncClose_throws
+ *   - test_asyncClose_does_not_throw_without_callback
+ * - (asyncThread && !mDBConn) => AsyncCloseConnection used, although no close
+ *   is required.  Note that this is only possible in the event that
+ *   openAsyncDatabase was used and we failed to open the database.
+ *   Additionally, the async connection will never be exposed to the caller and
+ *   AsyncInitDatabase will be the one to (automatically) call AsyncClose.
+ *   - test_asyncClose_failed_open
+ * - (!asyncThread && mDBConn) => Close() invoked, actually closes
+ *   - test_asyncClose_on_sync_db
+ * - (!asyncThread && !mDBConn) => Close() invoked, no close needed, errors.
+ *   This happens if the database has already been closed.
+ *   - test_double_asyncClose_throws
+ */
+
+/**
+ * Sanity check that our close indeed happens after asynchronously executed
+ * statements scheduled during the same turn of the event loop.  Note that we
+ * just care that the statement says it completed without error, we're not
+ * worried that the close will happen and then the statement will magically
+ * complete.
+ */
+add_task(async function test_asyncClose_does_not_complete_before_statements() {
+  let db = Services.storage.openDatabase(getTestDB());
+  let stmt = db.createStatement("SELECT * FROM sqlite_master");
+  // Issue the executeAsync but don't yield for it...
+  let asyncStatementPromise = executeAsync(stmt);
+  stmt.finalize();
+
+  // Issue the close.  (And now the order of yielding doesn't matter.)
+  // Branch coverage: (asyncThread && mDBConn)
+  await asyncClose(db);
+  equal(
+    await asyncStatementPromise,
+    Ci.mozIStorageStatementCallback.REASON_FINISHED
+  );
+});
+
+/**
+ * Open an async database (ensures the async thread is created) and then invoke
+ * AsyncClose() twice without yielding control flow.  The first will initiate
+ * the actual async close after calling setClosedState which synchronously
+ * impacts what the second call will observe.  The second call will then see the
+ * async thread is not available and fall back to invoking Close() which will
+ * notice the mDBConn is already gone.
+ */
+if (!AppConstants.DEBUG) {
+  add_task(async function test_double_asyncClose_throws() {
+    let db = await openAsyncDatabase(getTestDB());
+
+    // (Don't yield control flow yet, save the promise for after we make the
+    // second call.)
+    // Branch coverage: (asyncThread && mDBConn)
+    let realClosePromise = await asyncClose(db);
+    try {
+      // Branch coverage: (!asyncThread && !mDBConn)
+      db.asyncClose();
+      ok(false, "should have thrown");
+    } catch (e) {
+      equal(e.result, Cr.NS_ERROR_NOT_INITIALIZED);
+    }
+
+    await realClosePromise;
+  });
+}
+
+/**
+ * Create a sync db connection and never take it asynchronous and then call
+ * asyncClose on it.  This will bring the async thread to life to perform the
+ * shutdown to avoid blocking the main thread, although we won't be able to
+ * tell the difference between this happening and the method secretly shunting
+ * to close().
+ */
+add_task(async function test_asyncClose_on_sync_db() {
+  let db = Services.storage.openDatabase(getTestDB());
+
+  // Branch coverage: (!asyncThread && mDBConn)
+  await asyncClose(db);
+  ok(true, "closed sync connection asynchronously");
+});
+
+/**
+ * Fail to asynchronously open a DB in order to get an async thread existing
+ * without having an open database and asyncClose invoked.  As per the file
+ * doc-block, note that asyncClose will automatically be invoked by the
+ * AsyncInitDatabase when it fails to open the database.  We will never be
+ * provided with a reference to the connection and so cannot call AsyncClose on
+ * it ourselves.
+ */
+add_task(async function test_asyncClose_failed_open() {
+  // This will fail and the promise will be rejected.
+  let openPromise = openAsyncDatabase(getFakeDB());
+  await openPromise.then(
+    () => {
+      ok(false, "we should have failed to open the db; this test is broken!");
+    },
+    () => {
+      ok(true, "correctly failed to open db; bg asyncClose should happen");
+    }
+  );
+  // (NB: we are unable to observe the thread shutdown, but since we never open
+  // a database, this test is not going to interfere with other tests so much.)
+});
+
+// THE TEST BELOW WANTS TO BE THE LAST TEST WE RUN.  DO NOT MAKE IT SAD.
+/**
+ * Verify that asyncClose without a callback does not explode.  Without a
+ * callback the shutdown is not actually observable, so we run this test last
+ * in order to avoid weird overlaps.
+ */
+add_task(async function test_asyncClose_does_not_throw_without_callback() {
+  let db = await openAsyncDatabase(getTestDB());
+  // Branch coverage: (asyncThread && mDBConn)
+  db.asyncClose();
+  ok(true, "if we shutdown cleanly and do not crash, then we succeeded");
+});
+// OBEY SHOUTING UPPER-CASE COMMENTS.
+// ADD TESTS ABOVE THE FORMER TEST, NOT BELOW IT.
diff --git a/storage/test/unit/test_connection_executeAsync.js b/storage/test/unit/test_connection_executeAsync.js
new file mode 100644
index 0000000000..a77299ba3b
--- /dev/null
+++ b/storage/test/unit/test_connection_executeAsync.js
@@ -0,0 +1,175 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * This file tests the functionality of mozIStorageConnection::executeAsync for
+ * both mozIStorageStatement and mozIStorageAsyncStatement.
+ *
+ * A single database connection is used for the entirety of the test, which is
+ * a legacy thing, but we otherwise use the modern promise-based driver and
+ * async helpers.
+ */
+
+const INTEGER = 1;
+const TEXT = "this is test text";
+const REAL = 3.23;
+const BLOB = [1, 2];
+
+add_task(async function test_first_create_and_add() {
+  // synchronously open the database and let gDBConn hold onto it because we
+  // use this database
+  let db = getOpenedDatabase();
+  // synchronously set up our table *that will be used for the rest of the file*
+  db.executeSimpleSQL(
+    "CREATE TABLE test (" +
+      "id INTEGER, " +
+      "string TEXT, " +
+      "number REAL, " +
+      "nuller NULL, " +
+      "blober BLOB" +
+      ")"
+  );
+
+  let stmts = [];
+  stmts[0] = db.createStatement(
+    "INSERT INTO test (id, string, number, nuller, blober) VALUES (?, ?, ?, ?, ?)"
+  );
+  stmts[0].bindByIndex(0, INTEGER);
+  stmts[0].bindByIndex(1, TEXT);
+  stmts[0].bindByIndex(2, REAL);
+  stmts[0].bindByIndex(3, null);
+  stmts[0].bindBlobByIndex(4, BLOB, BLOB.length);
+  stmts[1] = getOpenedDatabase().createAsyncStatement(
+    "INSERT INTO test (string, number, nuller, blober) VALUES (?, ?, ?, ?)"
+  );
+  stmts[1].bindByIndex(0, TEXT);
+  stmts[1].bindByIndex(1, REAL);
+  stmts[1].bindByIndex(2, null);
+  stmts[1].bindBlobByIndex(3, BLOB, BLOB.length);
+
+  // asynchronously execute the statements
+  let execResult = await executeMultipleStatementsAsync(
+    db,
+    stmts,
+    function (aResultSet) {
+      ok(false, "we only did inserts so we should not have gotten results!");
+    }
+  );
+  equal(
+    Ci.mozIStorageStatementCallback.REASON_FINISHED,
+    execResult,
+    "execution should have finished successfully."
+  );
+
+  // Check that the result is in the table
+  let stmt = db.createStatement(
+    "SELECT string, number, nuller, blober FROM test WHERE id = ?"
+  );
+  stmt.bindByIndex(0, INTEGER);
+  try {
+    Assert.ok(stmt.executeStep());
+    Assert.equal(TEXT, stmt.getString(0));
+    Assert.equal(REAL, stmt.getDouble(1));
+    Assert.ok(stmt.getIsNull(2));
+    let count = { value: 0 };
+    let blob = { value: null };
+    stmt.getBlob(3, count, blob);
+    Assert.equal(BLOB.length, count.value);
+    for (let i = 0; i < BLOB.length; i++) {
+      Assert.equal(BLOB[i], blob.value[i]);
+    }
+  } finally {
+    stmt.finalize();
+  }
+
+  // Make sure we have two rows in the table
+  stmt = db.createStatement("SELECT COUNT(1) FROM test");
+  try {
+    Assert.ok(stmt.executeStep());
+    Assert.equal(2, stmt.getInt32(0));
+  } finally {
+    stmt.finalize();
+  }
+
+  stmts[0].finalize();
+  stmts[1].finalize();
+});
+
+add_task(async function test_last_multiple_bindings_on_statements() {
+  // This tests to make sure that we pass all the statements multiply bound
+  // parameters when we call executeAsync.
+  const AMOUNT_TO_ADD = 5;
+  const ITERATIONS = 5;
+
+  let stmts = [];
+  let db = getOpenedDatabase();
+  let sqlString =
+    "INSERT INTO test (id, string, number, nuller, blober) " +
+    "VALUES (:int, :text, :real, :null, :blob)";
+  // We run the same statement twice, and should insert 2 * AMOUNT_TO_ADD.
+  for (let i = 0; i < ITERATIONS; i++) {
+    // alternate the type of statement we create
+    if (i % 2) {
+      stmts[i] = db.createStatement(sqlString);
+    } else {
+      stmts[i] = db.createAsyncStatement(sqlString);
+    }
+
+    let params = stmts[i].newBindingParamsArray();
+    for (let j = 0; j < AMOUNT_TO_ADD; j++) {
+      let bp = params.newBindingParams();
+      bp.bindByName("int", INTEGER);
+      bp.bindByName("text", TEXT);
+      bp.bindByName("real", REAL);
+      bp.bindByName("null", null);
+      bp.bindBlobByName("blob", BLOB);
+      params.addParams(bp);
+    }
+    stmts[i].bindParameters(params);
+  }
+
+  // Get our current number of rows in the table.
+  let currentRows = 0;
+  let countStmt = getOpenedDatabase().createStatement(
+    "SELECT COUNT(1) AS count FROM test"
+  );
+  try {
+    Assert.ok(countStmt.executeStep());
+    currentRows = countStmt.row.count;
+  } finally {
+    countStmt.reset();
+  }
+
+  // Execute asynchronously.
+  let execResult = await executeMultipleStatementsAsync(
+    db,
+    stmts,
+    function (aResultSet) {
+      ok(false, "we only did inserts so we should not have gotten results!");
+    }
+  );
+  equal(
+    Ci.mozIStorageStatementCallback.REASON_FINISHED,
+    execResult,
+    "execution should have finished successfully."
+  );
+
+  // Check to make sure we added all of our rows.
+  try {
+    Assert.ok(countStmt.executeStep());
+    Assert.equal(currentRows + ITERATIONS * AMOUNT_TO_ADD, countStmt.row.count);
+  } finally {
+    countStmt.finalize();
+  }
+
+  stmts.forEach(stmt => stmt.finalize());
+
+  // we are the last test using this connection and since it has gone async
+  // we *must* call asyncClose on it.
+  await asyncClose(db);
+  gDBConn = null;
+});
+
+// If you add a test down here you will need to move the asyncClose or clean
+// things up a little more.
diff --git a/storage/test/unit/test_connection_executeSimpleSQLAsync.js b/storage/test/unit/test_connection_executeSimpleSQLAsync.js
new file mode 100644
index 0000000000..00bdda7e03
--- /dev/null
+++ b/storage/test/unit/test_connection_executeSimpleSQLAsync.js
@@ -0,0 +1,94 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * This file tests the functionality of
+ * mozIStorageAsyncConnection::executeSimpleSQLAsync.
+ */
+
+const INTEGER = 1;
+const TEXT = "this is test text";
+const REAL = 3.23;
+
+add_task(async function test_create_and_add() {
+  let adb = await openAsyncDatabase(getTestDB());
+
+  let completion = await executeSimpleSQLAsync(
+    adb,
+    "CREATE TABLE test (id INTEGER, string TEXT, number REAL)"
+  );
+
+  Assert.equal(Ci.mozIStorageStatementCallback.REASON_FINISHED, completion);
+
+  completion = await executeSimpleSQLAsync(
+    adb,
+    "INSERT INTO test (id, string, number) " +
+      "VALUES (" +
+      INTEGER +
+      ', "' +
+      TEXT +
+      '", ' +
+      REAL +
+      ")"
+  );
+
+  Assert.equal(Ci.mozIStorageStatementCallback.REASON_FINISHED, completion);
+
+  let result = null;
+
+  completion = await executeSimpleSQLAsync(
+    adb,
+    "SELECT string, number FROM test WHERE id = 1",
+    function (aResultSet) {
+      result = aResultSet.getNextRow();
+      Assert.equal(2, result.numEntries);
+      Assert.equal(TEXT, result.getString(0));
+      Assert.equal(REAL, result.getDouble(1));
+    }
+  );
+
+  Assert.equal(Ci.mozIStorageStatementCallback.REASON_FINISHED, completion);
+  Assert.notEqual(result, null);
+  result = null;
+
+  await executeSimpleSQLAsync(
+    adb,
+    "SELECT COUNT(0) FROM test",
+    function (aResultSet) {
+      result = aResultSet.getNextRow();
+      Assert.equal(1, result.getInt32(0));
+    }
+  );
+
+  Assert.notEqual(result, null);
+
+  await asyncClose(adb);
+});
+
+add_task(async function test_asyncClose_does_not_complete_before_statement() {
+  let adb = await openAsyncDatabase(getTestDB());
+  let executed = false;
+
+  let reason = await executeSimpleSQLAsync(
+    adb,
+    "SELECT * FROM test",
+    function (aResultSet) {
+      let result = aResultSet.getNextRow();
+
+      Assert.notEqual(result, null);
+      Assert.equal(3, result.numEntries);
+      Assert.equal(INTEGER, result.getInt32(0));
+      Assert.equal(TEXT, result.getString(1));
+      Assert.equal(REAL, result.getDouble(2));
+      executed = true;
+    }
+  );
+
+  Assert.equal(Ci.mozIStorageStatementCallback.REASON_FINISHED, reason);
+
+  // Ensure that the statement executed to completion.
+  Assert.ok(executed);
+
+  await asyncClose(adb);
+});
diff --git a/storage/test/unit/test_connection_failsafe_close.js b/storage/test/unit/test_connection_failsafe_close.js
new file mode 100644
index 0000000000..d4fa6d1503
--- /dev/null
+++ b/storage/test/unit/test_connection_failsafe_close.js
@@ -0,0 +1,35 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * This file tests edge-cases related to mozStorageService::unregisterConnection
+ * in the face of failsafe closing at destruction time which results in
+ * SpinningSynchronousClose being invoked which can "resurrect" the connection
+ * and result in a second call to unregisterConnection.
+ *
+ * See https://bugzilla.mozilla.org/show_bug.cgi?id=1413501 for more context.
+ */
+
+add_task(async function test_failsafe_close_of_async_connection() {
+  // get the db
+  let db = getOpenedDatabase();
+
+  // do something async
+  let callbackInvoked = new Promise(resolve => {
+    db.executeSimpleSQLAsync("CREATE TABLE test (id INTEGER)", {
+      handleCompletion: resolve,
+    });
+  });
+
+  // drop our reference and force a GC so the only live reference is owned by
+  // the async statement.
+  db = gDBConn = null;
+  // (we don't need to cycle collect)
+  Cu.forceGC();
+
+  // now we need to wait for that callback to have completed.
+  await callbackInvoked;
+
+  Assert.ok(true, "if we shutdown cleanly and do not crash, then we succeeded");
+});
diff --git a/storage/test/unit/test_connection_interrupt.js b/storage/test/unit/test_connection_interrupt.js
new file mode 100644
index 0000000000..e257e9af82
--- /dev/null
+++ b/storage/test/unit/test_connection_interrupt.js
@@ -0,0 +1,125 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// This file tests the functionality of mozIStorageAsyncConnection::interrupt
+// in the asynchronous case.
+add_task(async function test_wr_async_conn() {
+  // Interrupt cannot be used on R/W async connections.
+  let db = await openAsyncDatabase(getTestDB());
+  await db.interrupt();
+  info("should be able to interrupt a R/W async connection");
+  await asyncClose(db);
+});
+
+add_task(async function test_closed_conn() {
+  let db = await openAsyncDatabase(getTestDB(), { readOnly: true });
+  await asyncClose(db);
+  Assert.throws(
+    () => db.interrupt(),
+    /NS_ERROR_NOT_INITIALIZED/,
+    "interrupt() should throw if invoked on a closed connection"
+  );
+});
+
+add_task(
+  {
+    // We use a timeout in the test that may be insufficient on Android emulators.
+    // We don't really need the Android coverage, so skip on Android.
+    skip_if: () => AppConstants.platform == "android",
+  },
+  async function test_async_conn() {
+    let db = await openAsyncDatabase(getTestDB(), { readOnly: true });
+    // This query is built to hang forever.
+    let stmt = db.createAsyncStatement(`
+    WITH RECURSIVE test(n) AS (
+      VALUES(1)
+      UNION ALL
+      SELECT n + 1 FROM test
+    )
+    SELECT t.n
+    FROM test,test AS t`);
+
+    let completePromise = new Promise((resolve, reject) => {
+      let listener = {
+        handleResult(aResultSet) {
+          reject();
+        },
+        handleError(aError) {
+          reject();
+        },
+        handleCompletion(aReason) {
+          resolve(aReason);
+        },
+      };
+      stmt.executeAsync(listener);
+      stmt.finalize();
+    });
+
+    // Wait for the statement to be executing.
+    // This is not rock-solid, see the discussion in bug 1320301. A better
+    // approach will be evaluated in a separate bug.
+    await new Promise(resolve => do_timeout(500, resolve));
+
+    db.interrupt();
+
+    Assert.equal(
+      await completePromise,
+      Ci.mozIStorageStatementCallback.REASON_CANCELED,
+      "Should have been canceled"
+    );
+
+    await asyncClose(db);
+  }
+);
+
+add_task(
+  {
+    // We use a timeout in the test that may be insufficient on Android emulators.
+    // We don't really need the Android coverage, so skip on Android.
+    skip_if: () => AppConstants.platform == "android",
+  },
+  async function test_async_conn() {
+    let db = await openAsyncDatabase(getTestDB());
+    // This query is built to hang forever.
+    let stmt = db.createAsyncStatement(`
+    WITH RECURSIVE test(n) AS (
+      VALUES(1)
+      UNION ALL
+      SELECT n + 1 FROM test
+    )
+    SELECT t.n
+    FROM test,test AS t`);
+
+    let completePromise = new Promise((resolve, reject) => {
+      let listener = {
+        handleResult(aResultSet) {
+          reject();
+        },
+        handleError(aError) {
+          reject();
+        },
+        handleCompletion(aReason) {
+          resolve(aReason);
+        },
+      };
+      stmt.executeAsync(listener);
+      stmt.finalize();
+    });
+
+    // Wait for the statement to be executing.
+    // This is not rock-solid, see the discussion in bug 1320301. A better
+    // approach will be evaluated in a separate bug.
+    await new Promise(resolve => do_timeout(500, resolve));
+
+    // We are going to interrupt a database connection
+    db.interrupt();
+
+    Assert.equal(
+      await completePromise,
+      Ci.mozIStorageStatementCallback.REASON_CANCELED,
+      "Should have been able to cancel even for R/W database"
+    );
+
+    await asyncClose(db);
+  }
+);
diff --git a/storage/test/unit/test_connection_online_backup.js b/storage/test/unit/test_connection_online_backup.js
new file mode 100644
index 0000000000..3599d8c824
--- /dev/null
+++ b/storage/test/unit/test_connection_online_backup.js
@@ -0,0 +1,211 @@
+/* Any copyright is dedicated to the Public Domain.
+http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/**
+ * This test file tests the backupToFileAsync function on
+ * mozIStorageAsyncConnection, which is implemented for mozStorageConnection.
+ * (but not implemented for mozilla::dom::cache::Connection).
+ */
+
+// The name of the backup database file that will be created.
+const BACKUP_FILE_NAME = "test_storage.sqlite.backup";
+// The number of rows to insert into the test table in the source
+// database.
+const TEST_ROWS = 10;
+// The page size to set on the source database. During setup, we assert that
+// this does not match the default page size.
+const TEST_PAGE_SIZE = 512;
+
+/**
+ * This setup function creates a table inside of the test database and inserts
+ * some test rows. Critically, it keeps the connection to the database _open_
+ * so that we can test the scenario where a database is copied with existing
+ * open connections.
+ *
+ * The database is closed in a cleanup function.
+ */
+add_setup(async () => {
+  let conn = await openAsyncDatabase(getTestDB());
+
+  Assert.notEqual(
+    conn.defaultPageSize,
+    TEST_PAGE_SIZE,
+    "Should not default to having the TEST_PAGE_SIZE"
+  );
+
+  await executeSimpleSQLAsync(conn, "PRAGMA page_size = " + TEST_PAGE_SIZE);
+
+  let createStmt = conn.createAsyncStatement("CREATE TABLE test(name TEXT)");
+  await executeAsync(createStmt);
+  createStmt.finalize();
+
+  registerCleanupFunction(async () => {
+    await asyncClose(conn);
+  });
+});
+
+/**
+ * Erases the test table and inserts TEST_ROWS rows into it.
+ *
+ * @param {mozIStorageAsyncConnection} connection
+ *   The connection to use to prepare the database.
+ * @returns {Promise<undefined>}
+ */
+async function prepareSourceDatabase(connection) {
+  await executeSimpleSQLAsync(connection, "DELETE from test");
+  for (let i = 0; i < TEST_ROWS; ++i) {
+    let name = `Database row #${i}`;
+    let stmt = connection.createAsyncStatement(
+      "INSERT INTO test (name) VALUES (:name)"
+    );
+    stmt.params.name = name;
+    let result = await executeAsync(stmt);
+    stmt.finalize();
+    Assert.ok(Components.isSuccessCode(result), `Inserted test row #${i}`);
+  }
+}
+
+/**
+ * Gets the test DB prepared with the testing table and rows.
+ *
+ * @returns {Promise<mozIStorageAsyncConnection>}
+ */
+async function getPreparedAsyncDatabase() {
+  let connection = await openAsyncDatabase(getTestDB());
+  await prepareSourceDatabase(connection);
+  return connection;
+}
+
+/**
+ * Creates a copy of the database connected to via connection, and
+ * returns an nsIFile pointing at the created copy file once the
+ * copy is complete.
+ *
+ * @param {mozIStorageAsyncConnection} connection
+ *   A connection to a database that should be copied.
+ * @returns {Promise<nsIFile>}
+ */
+async function createCopy(connection) {
+  let destFilePath = PathUtils.join(PathUtils.profileDir, BACKUP_FILE_NAME);
+  let destFile = await IOUtils.getFile(destFilePath);
+  Assert.ok(
+    !(await IOUtils.exists(destFilePath)),
+    "Backup file shouldn't exist yet."
+  );
+
+  await new Promise(resolve => {
+    connection.backupToFileAsync(destFile, result => {
+      Assert.ok(Components.isSuccessCode(result));
+      resolve(result);
+    });
+  });
+
+  return destFile;
+}
+
+/**
+ * Opens up the database at file, asserts that the page_size matches
+ * TEST_PAGE_SIZE, and that the number of rows in the test table matches
+ * expectedEntries. Closes the connection after these assertions.
+ *
+ * @param {nsIFile} file
+ *   The database file to be opened and queried.
+ * @param {number} [expectedEntries=TEST_ROWS]
+ *   The expected number of rows in the test table. Defaults to TEST_ROWS.
+ * @returns {Promise<undefined>}
+ */
+async function assertSuccessfulCopy(file, expectedEntries = TEST_ROWS) {
+  let conn = await openAsyncDatabase(file);
+
+  await executeSimpleSQLAsync(conn, "PRAGMA page_size", resultSet => {
+    let result = resultSet.getNextRow();
+    Assert.equal(TEST_PAGE_SIZE, result.getResultByIndex(0).getAsUint32());
+  });
+
+  let stmt = conn.createAsyncStatement("SELECT COUNT(*) FROM test");
+  let results = await new Promise(resolve => {
+    executeAsync(stmt, resolve);
+  });
+  stmt.finalize();
+  let row = results.getNextRow();
+  let count = row.getResultByName("COUNT(*)");
+  Assert.equal(count, expectedEntries, "Got the expected entries");
+
+  Assert.ok(
+    !file.leafName.endsWith(".tmp"),
+    "Should not end in .tmp extension"
+  );
+
+  await asyncClose(conn);
+}
+
+/**
+ * Test the basic behaviour of backupToFileAsync, and ensure that the copied
+ * database has the same characteristics and contents as the source database.
+ */
+add_task(async function test_backupToFileAsync() {
+  let newConnection = await getPreparedAsyncDatabase();
+  let copyFile = await createCopy(newConnection);
+  Assert.ok(
+    await IOUtils.exists(copyFile.path),
+    "A new file was created by backupToFileAsync"
+  );
+
+  await assertSuccessfulCopy(copyFile);
+  await IOUtils.remove(copyFile.path);
+  await asyncClose(newConnection);
+});
+
+/**
+ * Tests that if insertions are underway during a copy, that those insertions
+ * show up in the copied database.
+ */
+add_task(async function test_backupToFileAsync_during_insert() {
+  let newConnection = await getPreparedAsyncDatabase();
+  const NEW_ENTRIES = 5;
+
+  let copyFilePromise = createCopy(newConnection);
+  let inserts = [];
+  for (let i = 0; i < NEW_ENTRIES; ++i) {
+    let name = `New database row #${i}`;
+    let stmt = newConnection.createAsyncStatement(
+      "INSERT INTO test (name) VALUES (:name)"
+    );
+    stmt.params.name = name;
+    inserts.push(executeAsync(stmt));
+    stmt.finalize();
+  }
+  await Promise.all(inserts);
+  let copyFile = await copyFilePromise;
+
+  Assert.ok(
+    await IOUtils.exists(copyFile.path),
+    "A new file was created by backupToFileAsync"
+  );
+
+  await assertSuccessfulCopy(copyFile, TEST_ROWS + NEW_ENTRIES);
+  await IOUtils.remove(copyFile.path);
+  await asyncClose(newConnection);
+});
+
+/**
+ * Tests the behaviour of backupToFileAsync as exposed through Sqlite.sys.mjs.
+ */
+add_task(async function test_backupToFileAsync_via_Sqlite_module() {
+  let xpcomConnection = await getPreparedAsyncDatabase();
+  let moduleConnection = await Sqlite.openConnection({
+    path: xpcomConnection.databaseFile.path,
+  });
+
+  let copyFilePath = PathUtils.join(PathUtils.profileDir, BACKUP_FILE_NAME);
+  await moduleConnection.backup(copyFilePath);
+  let copyFile = await IOUtils.getFile(copyFilePath);
+  Assert.ok(await IOUtils.exists(copyFilePath), "A new file was created");
+
+  await assertSuccessfulCopy(copyFile);
+  await IOUtils.remove(copyFile.path);
+  await moduleConnection.close();
+  await asyncClose(xpcomConnection);
+});
diff --git a/storage/test/unit/test_default_journal_size_limit.js b/storage/test/unit/test_default_journal_size_limit.js
new file mode 100644
index 0000000000..f2d28b9aa4
--- /dev/null
+++ b/storage/test/unit/test_default_journal_size_limit.js
@@ -0,0 +1,44 @@
+/* Any copyright is dedicated to the Public Domain.
+ * https://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests defaul journal_size_limit
+
+async function check_journal_size(db) {
+  let stmt = db.createAsyncStatement("PRAGMA journal_size_limit");
+  let value = await new Promise((resolve, reject) => {
+    stmt.executeAsync({
+      handleResult(resultSet) {
+        resolve(resultSet.getNextRow().getResultByIndex(0));
+      },
+      handleError(error) {
+        reject();
+      },
+      handleCompletion() {},
+    });
+  });
+  Assert.greater(value, 0, "There is a positive journal_size_limit");
+  stmt.finalize();
+  await new Promise(resolve => db.asyncClose(resolve));
+}
+
+async function getDbPath(name) {
+  let path = PathUtils.join(PathUtils.profileDir, name + ".sqlite");
+  Assert.ok(!(await IOUtils.exists(path)));
+  return path;
+}
+
+add_task(async function () {
+  await check_journal_size(
+    Services.storage.openDatabase(
+      new FileUtils.File(await getDbPath("journal"))
+    )
+  );
+  await check_journal_size(
+    Services.storage.openUnsharedDatabase(
+      new FileUtils.File(await getDbPath("journalUnshared"))
+    )
+  );
+  await check_journal_size(
+    await openAsyncDatabase(new FileUtils.File(await getDbPath("journalAsync")))
+  );
+});
diff --git a/storage/test/unit/test_js_helpers.js b/storage/test/unit/test_js_helpers.js
new file mode 100644
index 0000000000..da533a78fc
--- /dev/null
+++ b/storage/test/unit/test_js_helpers.js
@@ -0,0 +1,150 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set sw=2 ts=2 sts=2 et : */
+/**
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+/**
+ * This file tests that the JS language helpers in various ways.
+ */
+
+// Test Functions
+
+function test_params_enumerate() {
+  let stmt = createStatement("SELECT * FROM test WHERE id IN (:a, :b, :c)");
+
+  // Make sure they are right.
+  let expected = [0, 1, 2, "a", "b", "c", "length"];
+  let index = 0;
+  for (let name in stmt.params) {
+    if (name == "QueryInterface") {
+      continue;
+    }
+    Assert.equal(name, expected[index++]);
+  }
+  Assert.equal(index, 7);
+}
+
+function test_params_prototype() {
+  let stmt = createStatement("SELECT * FROM sqlite_master");
+
+  // Set a property on the prototype and make sure it exist (will not be a
+  // bindable parameter, however).
+  Object.getPrototypeOf(stmt.params).test = 2;
+  Assert.equal(stmt.params.test, 2);
+
+  delete Object.getPrototypeOf(stmt.params).test;
+  stmt.finalize();
+}
+
+function test_row_prototype() {
+  let stmt = createStatement("SELECT * FROM sqlite_master");
+
+  Assert.ok(stmt.executeStep());
+
+  // Set a property on the prototype and make sure it exists (will not be in the
+  // results, however).
+  Object.getPrototypeOf(stmt.row).test = 2;
+  Assert.equal(stmt.row.test, 2);
+
+  // Clean up after ourselves.
+  delete Object.getPrototypeOf(stmt.row).test;
+  stmt.finalize();
+}
+
+function test_row_enumerate() {
+  let stmt = createStatement("SELECT * FROM test");
+
+  Assert.ok(stmt.executeStep());
+
+  let expected = ["id", "string"];
+  let expected_values = [123, "foo"];
+  let index = 0;
+  for (let name in stmt.row) {
+    Assert.equal(name, expected[index]);
+    Assert.equal(stmt.row[name], expected_values[index]);
+    index++;
+  }
+  Assert.equal(index, 2);
+
+  // Save off the row helper, then forget the statement and trigger a GC.  We
+  // want to ensure that if the row helper is retained but the statement is
+  // destroyed, that no crash occurs and that the late access attempt simply
+  // throws an error.
+  let savedOffRow = stmt.row;
+  stmt = null;
+  Cu.forceGC();
+  Assert.throws(
+    () => {
+      return savedOffRow.string;
+    },
+    /NS_ERROR_NOT_INITIALIZED/,
+    "GC'ed statement should throw"
+  );
+}
+
+function test_params_gets_sync() {
+  // Added for bug 562866.
+  /*
+  let stmt = createStatement(
+    "SELECT * FROM test WHERE id IN (:a, :b, :c)"
+  );
+
+  // Make sure we do not assert in getting the value.
+  let originalCount = Object.getOwnPropertyNames(stmt.params).length;
+  let expected = ["a", "b", "c"];
+  for (let name of expected) {
+    stmt.params[name];
+  }
+
+  // Now make sure we didn't magically get any additional properties.
+  let finalCount = Object.getOwnPropertyNames(stmt.params).length;
+  do_check_eq(originalCount + expected.length, finalCount);
+  */
+}
+
+function test_params_gets_async() {
+  // Added for bug 562866.
+  /*
+  let stmt = createAsyncStatement(
+    "SELECT * FROM test WHERE id IN (:a, :b, :c)"
+  );
+
+  // Make sure we do not assert in getting the value.
+  let originalCount = Object.getOwnPropertyNames(stmt.params).length;
+  let expected = ["a", "b", "c"];
+  for (let name of expected) {
+    stmt.params[name];
+  }
+
+  // Now make sure we didn't magically get any additional properties.
+  let finalCount = Object.getOwnPropertyNames(stmt.params).length;
+  do_check_eq(originalCount + expected.length, finalCount);
+  */
+}
+
+// Test Runner
+
+var tests = [
+  test_params_enumerate,
+  test_params_prototype,
+  test_row_enumerate,
+  test_row_prototype,
+  test_params_gets_sync,
+  test_params_gets_async,
+];
+function run_test() {
+  cleanup();
+
+  // Create our database.
+  getOpenedDatabase().executeSimpleSQL(
+    "CREATE TABLE test (id INTEGER PRIMARY KEY, string TEXT)"
+  );
+  getOpenedDatabase().executeSimpleSQL(
+    "INSERT INTO test (id, string) VALUES (123, 'foo')"
+  );
+
+  // Run the tests.
+  tests.forEach(test => test());
+}
diff --git a/storage/test/unit/test_levenshtein.js b/storage/test/unit/test_levenshtein.js
new file mode 100644
index 0000000000..a92b3a9559
--- /dev/null
+++ b/storage/test/unit/test_levenshtein.js
@@ -0,0 +1,66 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file tests the Levenshtein Distance function we've registered.
+
+function createUtf16Database() {
+  print("Creating the in-memory UTF-16-encoded database.");
+  let conn = Services.storage.openSpecialDatabase("memory");
+  conn.executeSimpleSQL("PRAGMA encoding = 'UTF-16'");
+
+  print("Make sure the encoding was set correctly and is now UTF-16.");
+  let stmt = conn.createStatement("PRAGMA encoding");
+  Assert.ok(stmt.executeStep());
+  let enc = stmt.getString(0);
+  stmt.finalize();
+
+  // The value returned will actually be UTF-16le or UTF-16be.
+  Assert.ok(enc === "UTF-16le" || enc === "UTF-16be");
+
+  return conn;
+}
+
+function check_levenshtein(db, s, t, expectedDistance) {
+  var stmt = db.createStatement("SELECT levenshteinDistance(:s, :t) AS result");
+  stmt.params.s = s;
+  stmt.params.t = t;
+  try {
+    Assert.ok(stmt.executeStep());
+    Assert.equal(expectedDistance, stmt.row.result);
+  } finally {
+    stmt.reset();
+    stmt.finalize();
+  }
+}
+
+function testLevenshtein(db) {
+  // Basic tests.
+  check_levenshtein(db, "", "", 0);
+  check_levenshtein(db, "foo", "", 3);
+  check_levenshtein(db, "", "bar", 3);
+  check_levenshtein(db, "yellow", "hello", 2);
+  check_levenshtein(db, "gumbo", "gambol", 2);
+  check_levenshtein(db, "kitten", "sitten", 1);
+  check_levenshtein(db, "sitten", "sittin", 1);
+  check_levenshtein(db, "sittin", "sitting", 1);
+  check_levenshtein(db, "kitten", "sitting", 3);
+  check_levenshtein(db, "Saturday", "Sunday", 3);
+  check_levenshtein(db, "YHCQPGK", "LAHYQQKPGKA", 6);
+
+  // Test SQL NULL handling.
+  check_levenshtein(db, "foo", null, null);
+  check_levenshtein(db, null, "bar", null);
+  check_levenshtein(db, null, null, null);
+
+  // The levenshteinDistance function allocates temporary memory on the stack
+  // if it can.  Test some strings long enough to force a heap allocation.
+  var dots1000 = Array(1001).join(".");
+  var dashes1000 = Array(1001).join("-");
+  check_levenshtein(db, dots1000, dashes1000, 1000);
+}
+
+function run_test() {
+  testLevenshtein(getOpenedDatabase());
+  testLevenshtein(createUtf16Database());
+}
diff --git a/storage/test/unit/test_like.js b/storage/test/unit/test_like.js
new file mode 100644
index 0000000000..91674a8816
--- /dev/null
+++ b/storage/test/unit/test_like.js
@@ -0,0 +1,199 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file tests our LIKE implementation since we override it for unicode
+
+function setup() {
+  getOpenedDatabase().createTable("t1", "x TEXT");
+
+  var stmt = createStatement("INSERT INTO t1 (x) VALUES ('a')");
+  stmt.execute();
+  stmt.finalize();
+
+  stmt = createStatement("INSERT INTO t1 (x) VALUES ('ab')");
+  stmt.execute();
+  stmt.finalize();
+
+  stmt = createStatement("INSERT INTO t1 (x) VALUES ('abc')");
+  stmt.execute();
+  stmt.finalize();
+
+  stmt = createStatement("INSERT INTO t1 (x) VALUES ('abcd')");
+  stmt.execute();
+  stmt.finalize();
+
+  stmt = createStatement("INSERT INTO t1 (x) VALUES ('acd')");
+  stmt.execute();
+  stmt.finalize();
+
+  stmt = createStatement("INSERT INTO t1 (x) VALUES ('abd')");
+  stmt.execute();
+  stmt.finalize();
+
+  stmt = createStatement("INSERT INTO t1 (x) VALUES ('bc')");
+  stmt.execute();
+  stmt.finalize();
+
+  stmt = createStatement("INSERT INTO t1 (x) VALUES ('bcd')");
+  stmt.execute();
+  stmt.finalize();
+
+  stmt = createStatement("INSERT INTO t1 (x) VALUES ('xyz')");
+  stmt.execute();
+  stmt.finalize();
+
+  stmt = createStatement("INSERT INTO t1 (x) VALUES ('ABC')");
+  stmt.execute();
+  stmt.finalize();
+
+  stmt = createStatement("INSERT INTO t1 (x) VALUES ('CDE')");
+  stmt.execute();
+  stmt.finalize();
+
+  stmt = createStatement("INSERT INTO t1 (x) VALUES ('ABC abc xyz')");
+  stmt.execute();
+  stmt.finalize();
+}
+
+function test_count() {
+  var stmt = createStatement("SELECT count(*) FROM t1;");
+  Assert.ok(stmt.executeStep());
+  Assert.equal(stmt.getInt32(0), 12);
+  stmt.reset();
+  stmt.finalize();
+}
+
+function test_like_1() {
+  var stmt = createStatement("SELECT x FROM t1 WHERE x LIKE ?;");
+  stmt.bindByIndex(0, "abc");
+  var solutions = ["abc", "ABC"];
+  Assert.ok(stmt.executeStep());
+  Assert.ok(solutions.includes(stmt.getString(0)));
+  Assert.ok(stmt.executeStep());
+  Assert.ok(solutions.includes(stmt.getString(0)));
+  Assert.ok(!stmt.executeStep());
+  stmt.reset();
+  stmt.finalize();
+}
+
+function test_like_2() {
+  var stmt = createStatement("SELECT x FROM t1 WHERE x LIKE ?;");
+  stmt.bindByIndex(0, "ABC");
+  var solutions = ["abc", "ABC"];
+  Assert.ok(stmt.executeStep());
+  Assert.ok(solutions.includes(stmt.getString(0)));
+  Assert.ok(stmt.executeStep());
+  Assert.ok(solutions.includes(stmt.getString(0)));
+  Assert.ok(!stmt.executeStep());
+  stmt.reset();
+  stmt.finalize();
+}
+
+function test_like_3() {
+  var stmt = createStatement("SELECT x FROM t1 WHERE x LIKE ?;");
+  stmt.bindByIndex(0, "aBc");
+  var solutions = ["abc", "ABC"];
+  Assert.ok(stmt.executeStep());
+  Assert.ok(solutions.includes(stmt.getString(0)));
+  Assert.ok(stmt.executeStep());
+  Assert.ok(solutions.includes(stmt.getString(0)));
+  Assert.ok(!stmt.executeStep());
+  stmt.reset();
+  stmt.finalize();
+}
+
+function test_like_4() {
+  var stmt = createStatement("SELECT x FROM t1 WHERE x LIKE ?;");
+  stmt.bindByIndex(0, "abc%");
+  var solutions = ["abc", "abcd", "ABC", "ABC abc xyz"];
+  Assert.ok(stmt.executeStep());
+  Assert.ok(solutions.includes(stmt.getString(0)));
+  Assert.ok(stmt.executeStep());
+  Assert.ok(solutions.includes(stmt.getString(0)));
+  Assert.ok(stmt.executeStep());
+  Assert.ok(solutions.includes(stmt.getString(0)));
+  Assert.ok(stmt.executeStep());
+  Assert.ok(solutions.includes(stmt.getString(0)));
+  Assert.ok(!stmt.executeStep());
+  stmt.reset();
+  stmt.finalize();
+}
+
+function test_like_5() {
+  var stmt = createStatement("SELECT x FROM t1 WHERE x LIKE ?;");
+  stmt.bindByIndex(0, "a_c");
+  var solutions = ["abc", "ABC"];
+  Assert.ok(stmt.executeStep());
+  Assert.ok(solutions.includes(stmt.getString(0)));
+  Assert.ok(stmt.executeStep());
+  Assert.ok(solutions.includes(stmt.getString(0)));
+  Assert.ok(!stmt.executeStep());
+  stmt.reset();
+  stmt.finalize();
+}
+
+function test_like_6() {
+  var stmt = createStatement("SELECT x FROM t1 WHERE x LIKE ?;");
+  stmt.bindByIndex(0, "ab%d");
+  var solutions = ["abcd", "abd"];
+  Assert.ok(stmt.executeStep());
+  Assert.ok(solutions.includes(stmt.getString(0)));
+  Assert.ok(stmt.executeStep());
+  Assert.ok(solutions.includes(stmt.getString(0)));
+  Assert.ok(!stmt.executeStep());
+  stmt.reset();
+  stmt.finalize();
+}
+
+function test_like_7() {
+  var stmt = createStatement("SELECT x FROM t1 WHERE x LIKE ?;");
+  stmt.bindByIndex(0, "a_c%");
+  var solutions = ["abc", "abcd", "ABC", "ABC abc xyz"];
+  Assert.ok(stmt.executeStep());
+  Assert.ok(solutions.includes(stmt.getString(0)));
+  Assert.ok(stmt.executeStep());
+  Assert.ok(solutions.includes(stmt.getString(0)));
+  Assert.ok(stmt.executeStep());
+  Assert.ok(solutions.includes(stmt.getString(0)));
+  Assert.ok(stmt.executeStep());
+  Assert.ok(solutions.includes(stmt.getString(0)));
+  Assert.ok(!stmt.executeStep());
+  stmt.reset();
+  stmt.finalize();
+}
+
+function test_like_8() {
+  var stmt = createStatement("SELECT x FROM t1 WHERE x LIKE ?;");
+  stmt.bindByIndex(0, "%bcd");
+  var solutions = ["abcd", "bcd"];
+  Assert.ok(stmt.executeStep());
+  Assert.ok(solutions.includes(stmt.getString(0)));
+  Assert.ok(stmt.executeStep());
+  Assert.ok(solutions.includes(stmt.getString(0)));
+  Assert.ok(!stmt.executeStep());
+  stmt.reset();
+  stmt.finalize();
+}
+
+var tests = [
+  test_count,
+  test_like_1,
+  test_like_2,
+  test_like_3,
+  test_like_4,
+  test_like_5,
+  test_like_6,
+  test_like_7,
+  test_like_8,
+];
+
+function run_test() {
+  setup();
+
+  for (var i = 0; i < tests.length; i++) {
+    tests[i]();
+  }
+
+  cleanup();
+}
diff --git a/storage/test/unit/test_like_escape.js b/storage/test/unit/test_like_escape.js
new file mode 100644
index 0000000000..66d6d1d583
--- /dev/null
+++ b/storage/test/unit/test_like_escape.js
@@ -0,0 +1,72 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const LATIN1_AE = "\xc6";
+const LATIN1_ae = "\xe6";
+
+function setup() {
+  getOpenedDatabase().createTable("t1", "x TEXT");
+
+  var stmt = createStatement(
+    "INSERT INTO t1 (x) VALUES ('foo/bar_baz%20cheese')"
+  );
+  stmt.execute();
+  stmt.finalize();
+
+  stmt = createStatement("INSERT INTO t1 (x) VALUES (?1)");
+  // insert LATIN_ae, but search on LATIN_AE
+  stmt.bindByIndex(0, "foo%20" + LATIN1_ae + "/_bar");
+  stmt.execute();
+  stmt.finalize();
+}
+
+function test_escape_for_like_ascii() {
+  const paramForLike = "oo/bar_baz%20chees";
+  const escapeChar = "/";
+
+  for (const utf8 of [false, true]) {
+    var stmt = createStatement("SELECT x FROM t1 WHERE x LIKE ?1 ESCAPE '/'");
+    var paramForLikeEscaped = utf8
+      ? stmt.escapeUTF8StringForLIKE(paramForLike, escapeChar)
+      : stmt.escapeStringForLIKE(paramForLike, escapeChar);
+    // verify that we escaped / _ and %
+    Assert.equal(paramForLikeEscaped, "oo//bar/_baz/%20chees");
+    // prepend and append with % for "contains"
+    stmt.bindByIndex(0, "%" + paramForLikeEscaped + "%");
+    stmt.executeStep();
+    Assert.equal("foo/bar_baz%20cheese", stmt.getString(0));
+    stmt.finalize();
+  }
+}
+
+function test_escape_for_like_non_ascii() {
+  const paramForLike = "oo%20" + LATIN1_AE + "/_ba";
+  const escapeChar = "/";
+
+  for (const utf8 of [false, true]) {
+    var stmt = createStatement("SELECT x FROM t1 WHERE x LIKE ?1 ESCAPE '/'");
+    var paramForLikeEscaped = utf8
+      ? stmt.escapeUTF8StringForLIKE(paramForLike, escapeChar)
+      : stmt.escapeStringForLIKE(paramForLike, escapeChar);
+    // verify that we escaped / _ and %
+    Assert.equal(paramForLikeEscaped, "oo/%20" + LATIN1_AE + "///_ba");
+    // prepend and append with % for "contains"
+    stmt.bindByIndex(0, "%" + paramForLikeEscaped + "%");
+    stmt.executeStep();
+    Assert.equal("foo%20" + LATIN1_ae + "/_bar", stmt.getString(0));
+    stmt.finalize();
+  }
+}
+
+var tests = [test_escape_for_like_ascii, test_escape_for_like_non_ascii];
+
+function run_test() {
+  setup();
+
+  for (var i = 0; i < tests.length; i++) {
+    tests[i]();
+  }
+
+  cleanup();
+}
diff --git a/storage/test/unit/test_locale_collation.js b/storage/test/unit/test_locale_collation.js
new file mode 100644
index 0000000000..96f2415451
--- /dev/null
+++ b/storage/test/unit/test_locale_collation.js
@@ -0,0 +1,291 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Bug 499990 - Locale-aware collation
+ *
+ * Tests our custom, locale-aware collating sequences.
+ */
+
+// The name of the file containing the strings we'll sort during this test.
+// The file's data is taken from intl/locale/tests/sort/us-ascii_base.txt and
+// and intl/locale/tests/sort/us-ascii_sort.txt.
+const DATA_BASENAME = "locale_collation.txt";
+
+// The test data from DATA_BASENAME is read into this array.
+var gStrings;
+
+// A connection to our in-memory UTF-16-encoded database.
+var gUtf16Conn;
+
+// Helper Functions
+
+/**
+ * Since we create a UTF-16 database we have to clean it up, in addition to
+ * the normal cleanup of Storage tests.
+ */
+function cleanupLocaleTests() {
+  print("-- Cleaning up test_locale_collation.js suite.");
+  gUtf16Conn.close();
+  cleanup();
+}
+
+/**
+ * Creates a test database similar to the default one created in
+ * head_storage.js, except that this one uses UTF-16 encoding.
+ *
+ * @return A connection to the database.
+ */
+function createUtf16Database() {
+  print("Creating the in-memory UTF-16-encoded database.");
+  let conn = Services.storage.openSpecialDatabase("memory");
+  conn.executeSimpleSQL("PRAGMA encoding = 'UTF-16'");
+
+  print("Make sure the encoding was set correctly and is now UTF-16.");
+  let stmt = conn.createStatement("PRAGMA encoding");
+  Assert.ok(stmt.executeStep());
+  let enc = stmt.getString(0);
+  stmt.finalize();
+
+  // The value returned will actually be UTF-16le or UTF-16be.
+  Assert.ok(enc === "UTF-16le" || enc === "UTF-16be");
+
+  return conn;
+}
+
+/**
+ * Compares aActual to aExpected, ensuring that the numbers and orderings of
+ * the two arrays' elements are the same.
+ *
+ * @param aActual
+ *        An array of strings retrieved from the database.
+ * @param aExpected
+ *        An array of strings to which aActual should be equivalent.
+ */
+function ensureResultsAreCorrect(aActual, aExpected) {
+  print("Actual results:   " + aActual);
+  print("Expected results: " + aExpected);
+
+  Assert.equal(aActual.length, aExpected.length);
+  for (let i = 0; i < aActual.length; i++) {
+    Assert.equal(aActual[i], aExpected[i]);
+  }
+}
+
+/**
+ * Synchronously SELECTs all rows from the test table of the given database
+ * using the given collation.
+ *
+ * @param  aCollation
+ *         The name of one of our custom locale collations.  The rows are
+ *         ordered by this collation.
+ * @param  aConn
+ *         A connection to either the UTF-8 database or the UTF-16 database.
+ * @return The resulting strings in an array.
+ */
+function getResults(aCollation, aConn) {
+  let results = [];
+  let stmt = aConn.createStatement(
+    "SELECT t FROM test ORDER BY t COLLATE " + aCollation + " ASC"
+  );
+  while (stmt.executeStep()) {
+    results.push(stmt.row.t);
+  }
+  stmt.finalize();
+  return results;
+}
+
+/**
+ * Inserts strings into our test table of the given database in the order given.
+ *
+ * @param aStrings
+ *        An array of strings.
+ * @param aConn
+ *        A connection to either the UTF-8 database or the UTF-16 database.
+ */
+function initTableWithStrings(aStrings, aConn) {
+  print("Initializing test table.");
+
+  aConn.executeSimpleSQL("DROP TABLE IF EXISTS test");
+  aConn.createTable("test", "t TEXT");
+  let stmt = aConn.createStatement("INSERT INTO test (t) VALUES (:t)");
+  aStrings.forEach(function (str) {
+    stmt.params.t = str;
+    stmt.execute();
+    stmt.reset();
+  });
+  stmt.finalize();
+}
+
+/**
+ * Returns a sorting function suitable for passing to Array.prototype.sort().
+ * The returned function uses the application's locale to compare strings.
+ *
+ * @param  aCollation
+ *         The name of one of our custom locale collations.  The sorting
+ *         strength is computed from this value.
+ * @return A function to use as a sorting callback.
+ */
+function localeCompare(aCollation) {
+  let sensitivity;
+
+  switch (aCollation) {
+    case "locale":
+      sensitivity = "base";
+      break;
+    case "locale_case_sensitive":
+      sensitivity = "case";
+      break;
+    case "locale_accent_sensitive":
+      sensitivity = "accent";
+      break;
+    case "locale_case_accent_sensitive":
+      sensitivity = "variant";
+      break;
+    default:
+      do_throw("Error in test: unknown collation '" + aCollation + "'");
+      break;
+  }
+  const collation = new Intl.Collator("en", { sensitivity });
+  return function (aStr1, aStr2) {
+    return collation.compare(aStr1, aStr2);
+  };
+}
+
+/**
+ * Reads in the test data from the file DATA_BASENAME and returns it as an array
+ * of strings.
+ *
+ * @return The test data as an array of strings.
+ */
+function readTestData() {
+  print("Reading in test data.");
+
+  let file = do_get_file(DATA_BASENAME);
+
+  let istream = Cc["@mozilla.org/network/file-input-stream;1"].createInstance(
+    Ci.nsIFileInputStream
+  );
+  istream.init(file, -1, -1, 0);
+  istream.QueryInterface(Ci.nsILineInputStream);
+
+  let line = {};
+  let lines = [];
+  while (istream.readLine(line)) {
+    lines.push(line.value);
+  }
+  istream.close();
+
+  return lines;
+}
+
+/**
+ * Gets the results from the given database using the given collation and
+ * ensures that they match gStrings sorted by the same collation.
+ *
+ * @param aCollation
+ *        The name of one of our custom locale collations.  The rows from the
+ *        database and the expected results are ordered by this collation.
+ * @param aConn
+ *        A connection to either the UTF-8 database or the UTF-16 database.
+ */
+function runTest(aCollation, aConn) {
+  ensureResultsAreCorrect(
+    getResults(aCollation, aConn),
+    gStrings.slice(0).sort(localeCompare(aCollation))
+  );
+}
+
+/**
+ * Gets the results from the UTF-8 database using the given collation and
+ * ensures that they match gStrings sorted by the same collation.
+ *
+ * @param aCollation
+ *        The name of one of our custom locale collations.  The rows from the
+ *        database and the expected results are ordered by this collation.
+ */
+function runUtf8Test(aCollation) {
+  runTest(aCollation, getOpenedDatabase());
+}
+
+/**
+ * Gets the results from the UTF-16 database using the given collation and
+ * ensures that they match gStrings sorted by the same collation.
+ *
+ * @param aCollation
+ *        The name of one of our custom locale collations.  The rows from the
+ *        database and the expected results are ordered by this collation.
+ */
+function runUtf16Test(aCollation) {
+  runTest(aCollation, gUtf16Conn);
+}
+
+/**
+ * Sets up the test suite.
+ */
+function setup() {
+  print("-- Setting up the test_locale_collation.js suite.");
+
+  gStrings = readTestData();
+
+  initTableWithStrings(gStrings, getOpenedDatabase());
+
+  gUtf16Conn = createUtf16Database();
+  initTableWithStrings(gStrings, gUtf16Conn);
+}
+
+// Test Runs
+
+var gTests = [
+  {
+    desc: "Case and accent sensitive UTF-8",
+    run: () => runUtf8Test("locale_case_accent_sensitive"),
+  },
+
+  {
+    desc: "Case sensitive, accent insensitive UTF-8",
+    run: () => runUtf8Test("locale_case_sensitive"),
+  },
+
+  {
+    desc: "Case insensitive, accent sensitive UTF-8",
+    run: () => runUtf8Test("locale_accent_sensitive"),
+  },
+
+  {
+    desc: "Case and accent insensitive UTF-8",
+    run: () => runUtf8Test("locale"),
+  },
+
+  {
+    desc: "Case and accent sensitive UTF-16",
+    run: () => runUtf16Test("locale_case_accent_sensitive"),
+  },
+
+  {
+    desc: "Case sensitive, accent insensitive UTF-16",
+    run: () => runUtf16Test("locale_case_sensitive"),
+  },
+
+  {
+    desc: "Case insensitive, accent sensitive UTF-16",
+    run: () => runUtf16Test("locale_accent_sensitive"),
+  },
+
+  {
+    desc: "Case and accent insensitive UTF-16",
+    run: () => runUtf16Test("locale"),
+  },
+];
+
+function run_test() {
+  setup();
+  gTests.forEach(function (test) {
+    print("-- Running test: " + test.desc);
+    test.run();
+  });
+  cleanupLocaleTests();
+}
diff --git a/storage/test/unit/test_minimizeMemory.js b/storage/test/unit/test_minimizeMemory.js
new file mode 100644
index 0000000000..e694ddc186
--- /dev/null
+++ b/storage/test/unit/test_minimizeMemory.js
@@ -0,0 +1,23 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// This file tests that invoking `Service::minimizeMemory` succeeds for sync
+// and async connections.
+
+function minimizeMemory() {
+  Services.storage
+    .QueryInterface(Ci.nsIObserver)
+    .observe(null, "memory-pressure", null);
+}
+
+add_task(async function test_minimizeMemory_async_connection() {
+  let db = await openAsyncDatabase(getTestDB());
+  minimizeMemory();
+  await asyncClose(db);
+});
+
+add_task(async function test_minimizeMemory_sync_connection() {
+  let db = getOpenedDatabase();
+  minimizeMemory();
+  db.close();
+});
diff --git a/storage/test/unit/test_page_size_is_32k.js b/storage/test/unit/test_page_size_is_32k.js
new file mode 100644
index 0000000000..4a91d13fdc
--- /dev/null
+++ b/storage/test/unit/test_page_size_is_32k.js
@@ -0,0 +1,31 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+// This file tests that dbs are using 32k pagesize
+
+const kExpectedPageSize = 32768; // 32K
+const kExpectedCacheSize = -2048; // 2MiB
+
+function check_size(db) {
+  var stmt = db.createStatement("PRAGMA page_size");
+  stmt.executeStep();
+  Assert.equal(stmt.getInt32(0), kExpectedPageSize);
+  stmt.finalize();
+  stmt = db.createStatement("PRAGMA cache_size");
+  stmt.executeStep();
+  Assert.equal(stmt.getInt32(0), kExpectedCacheSize);
+  stmt.finalize();
+}
+
+function new_file(name) {
+  var file = Services.dirsvc.get("ProfD", Ci.nsIFile);
+  file.append(name + ".sqlite");
+  Assert.ok(!file.exists());
+  return file;
+}
+
+function run_test() {
+  check_size(getDatabase(new_file("shared32k")));
+  check_size(Services.storage.openUnsharedDatabase(new_file("unshared32k")));
+}
diff --git a/storage/test/unit/test_persist_journal.js b/storage/test/unit/test_persist_journal.js
new file mode 100644
index 0000000000..1eea5c703e
--- /dev/null
+++ b/storage/test/unit/test_persist_journal.js
@@ -0,0 +1,89 @@
+/* Any copyright is dedicated to the Public Domain.
+ * https://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests the journal persists on close.
+
+async function check_journal_persists(db, journal) {
+  let path = db.databaseFile.path;
+  info(`testing ${path}`);
+  await new Promise(resolve => {
+    db.executeSimpleSQLAsync(`PRAGMA journal_mode = ${journal}`, {
+      handleCompletion: resolve,
+    });
+  });
+
+  await new Promise(resolve => {
+    db.executeSimpleSQLAsync("CREATE TABLE test (id INTEGER PRIMARY KEY)", {
+      handleCompletion: resolve,
+    });
+  });
+
+  if (journal == "wal") {
+    Assert.ok(await IOUtils.exists(path + "-wal"), "-wal exists before close");
+    Assert.greater(
+      (await IOUtils.stat(path + "-wal")).size,
+      0,
+      "-wal size is non-zero"
+    );
+  } else {
+    Assert.ok(
+      await IOUtils.exists(path + "-journal"),
+      "-journal exists before close"
+    );
+    Assert.equal(
+      (await IOUtils.stat(path + "-journal")).size,
+      0,
+      "-journal is truncated after every transaction"
+    );
+  }
+
+  await new Promise(resolve => db.asyncClose(resolve));
+
+  if (journal == "wal") {
+    Assert.ok(await IOUtils.exists(path + "-wal"), "-wal persists after close");
+    Assert.equal(
+      (await IOUtils.stat(path + "-wal")).size,
+      0,
+      "-wal has been truncated"
+    );
+  } else {
+    Assert.ok(
+      await IOUtils.exists(path + "-journal"),
+      "-journal persists after close"
+    );
+    Assert.equal(
+      (await IOUtils.stat(path + "-journal")).size,
+      0,
+      "-journal has been truncated"
+    );
+  }
+}
+
+async function getDbPath(name) {
+  let path = PathUtils.join(PathUtils.profileDir, name + ".sqlite");
+  Assert.ok(!(await IOUtils.exists(path)), "database should not exist");
+  return path;
+}
+
+add_task(async function () {
+  for (let journal of ["truncate", "wal"]) {
+    await check_journal_persists(
+      Services.storage.openDatabase(
+        new FileUtils.File(await getDbPath(`shared-${journal}`))
+      ),
+      journal
+    );
+    await check_journal_persists(
+      Services.storage.openUnsharedDatabase(
+        new FileUtils.File(await getDbPath(`unshared-${journal}`))
+      ),
+      journal
+    );
+    await check_journal_persists(
+      await openAsyncDatabase(
+        new FileUtils.File(await getDbPath(`async-${journal}`))
+      ),
+      journal
+    );
+  }
+});
diff --git a/storage/test/unit/test_readonly-immutable-nolock_vfs.js b/storage/test/unit/test_readonly-immutable-nolock_vfs.js
new file mode 100644
index 0000000000..5c11150b0a
--- /dev/null
+++ b/storage/test/unit/test_readonly-immutable-nolock_vfs.js
@@ -0,0 +1,47 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file tests the readonly-immutable-nolock VFS.
+
+add_task(async function test() {
+  const path = PathUtils.join(PathUtils.profileDir, "ro");
+  await IOUtils.makeDirectory(path);
+  const dbpath = PathUtils.join(path, "test-immutable.sqlite");
+
+  let conn = await Sqlite.openConnection({ path: dbpath });
+  await conn.execute("PRAGMA journal_mode = WAL");
+  await conn.execute("CREATE TABLE test (id INTEGER PRIMARY KEY)");
+  Assert.ok(await IOUtils.exists(dbpath + "-wal"), "wal journal exists");
+  await conn.close();
+
+  // The wal should have been merged at this point, but just in case...
+  info("Remove auxiliary files and set the folder as readonly");
+  await IOUtils.remove(dbpath + "-wal", { ignoreAbsent: true });
+  await IOUtils.setPermissions(path, 0o555);
+  registerCleanupFunction(async () => {
+    await IOUtils.setPermissions(path, 0o777);
+    await IOUtils.remove(path, { recursive: true });
+  });
+
+  // Windows doesn't disallow creating files in read only folders.
+  if (AppConstants.platform == "macosx" || AppConstants.platform == "linux") {
+    await Assert.rejects(
+      Sqlite.openConnection({ path: dbpath, readOnly: true }),
+      /NS_ERROR_FILE/,
+      "Should not be able to open the db because it can't create a wal journal"
+    );
+  }
+
+  // Open the database with ignoreLockingMode.
+  let conn2 = await Sqlite.openConnection({
+    path: dbpath,
+    ignoreLockingMode: true,
+  });
+  await conn2.execute("SELECT * FROM sqlite_master");
+  Assert.ok(
+    !(await IOUtils.exists(dbpath + "-wal")),
+    "wal journal was not created"
+  );
+  await conn2.close();
+});
diff --git a/storage/test/unit/test_retry_on_busy.js b/storage/test/unit/test_retry_on_busy.js
new file mode 100644
index 0000000000..bf7cdafdad
--- /dev/null
+++ b/storage/test/unit/test_retry_on_busy.js
@@ -0,0 +1,199 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/* eslint-disable mozilla/no-arbitrary-setTimeout */
+
+const { setTimeout } = ChromeUtils.importESModule(
+  "resource://gre/modules/Timer.sys.mjs"
+);
+
+function getProfileFile(name) {
+  let file = do_get_profile();
+  file.append(name);
+  return file;
+}
+
+function promiseAsyncDatabase(name, openOptions = 0) {
+  return new Promise((resolve, reject) => {
+    let file = getProfileFile(name);
+    const connOptions = Ci.mozIStorageService.CONNECTION_DEFAULT;
+    Services.storage.openAsyncDatabase(
+      file,
+      openOptions,
+      connOptions,
+      (status, connection) => {
+        if (!Components.isSuccessCode(status)) {
+          reject(new Error(`Failed to open database: ${status}`));
+        } else {
+          connection.QueryInterface(Ci.mozIStorageAsyncConnection);
+          resolve(connection);
+        }
+      }
+    );
+  });
+}
+
+function promiseClone(db, readOnly = false) {
+  return new Promise((resolve, reject) => {
+    db.asyncClone(readOnly, (status, clone) => {
+      if (!Components.isSuccessCode(status)) {
+        reject(new Error(`Failed to clone connection: ${status}`));
+      } else {
+        clone.QueryInterface(Ci.mozIStorageAsyncConnection);
+        resolve(clone);
+      }
+    });
+  });
+}
+
+function promiseClose(db) {
+  return new Promise((resolve, reject) => {
+    db.asyncClose(status => {
+      if (!Components.isSuccessCode(status)) {
+        reject(new Error(`Failed to close connection: ${status}`));
+      } else {
+        resolve();
+      }
+    });
+  });
+}
+
+function promiseExecuteStatement(statement) {
+  return new Promise((resolve, reject) => {
+    let rows = [];
+    statement.executeAsync({
+      handleResult(resultSet) {
+        let row = null;
+        do {
+          row = resultSet.getNextRow();
+          if (row) {
+            rows.push(row);
+          }
+        } while (row);
+      },
+      handleError(error) {
+        reject(new Error(`Failed to execute statement: ${error.message}`));
+      },
+      handleCompletion(reason) {
+        if (reason == Ci.mozIStorageStatementCallback.REASON_FINISHED) {
+          resolve(rows);
+        } else {
+          reject(new Error("Statement failed to execute or was cancelled"));
+        }
+      },
+    });
+  });
+}
+
+add_task(async function test_retry_on_busy() {
+  info("Open first writer in WAL mode and set up schema");
+  let db1 = await promiseAsyncDatabase("retry-on-busy.sqlite");
+
+  let walStmt = db1.createAsyncStatement(`PRAGMA journal_mode = WAL`);
+  await promiseExecuteStatement(walStmt);
+  let createAStmt = db1.createAsyncStatement(`CREATE TABLE a(
+    b INTEGER PRIMARY KEY
+  )`);
+  await promiseExecuteStatement(createAStmt);
+  let createPrevAStmt = db1.createAsyncStatement(`CREATE TEMP TABLE prevA(
+    curB INTEGER PRIMARY KEY,
+    prevB INTEGER NOT NULL
+  )`);
+  await promiseExecuteStatement(createPrevAStmt);
+  let createATriggerStmt = db1.createAsyncStatement(`
+    CREATE TEMP TRIGGER a_afterinsert_trigger
+    AFTER UPDATE ON a FOR EACH ROW
+    BEGIN
+      REPLACE INTO prevA(curB, prevB) VALUES(NEW.b, OLD.b);
+    END`);
+  await promiseExecuteStatement(createATriggerStmt);
+
+  info("Open second writer");
+  let db2 = await promiseClone(db1);
+
+  info("Attach second writer to new database");
+  let attachStmt = db2.createAsyncStatement(`ATTACH :path AS newDB`);
+  attachStmt.bindByName(
+    "path",
+    getProfileFile("retry-on-busy-attach.sqlite").path
+  );
+  await promiseExecuteStatement(attachStmt);
+
+  info("Create triggers on second writer");
+  let createCStmt = db2.createAsyncStatement(`CREATE TABLE newDB.c(
+    d INTEGER PRIMARY KEY
+  )`);
+  await promiseExecuteStatement(createCStmt);
+  let createCTriggerStmt = db2.createAsyncStatement(`
+    CREATE TEMP TRIGGER c_afterdelete_trigger
+    AFTER DELETE ON c FOR EACH ROW
+    BEGIN
+      INSERT INTO a(b) VALUES(OLD.d);
+    END`);
+  await promiseExecuteStatement(createCTriggerStmt);
+
+  info("Begin transaction on second writer");
+  let begin2Stmt = db2.createAsyncStatement("BEGIN IMMEDIATE");
+  await promiseExecuteStatement(begin2Stmt);
+
+  info(
+    "Begin transaction on first writer; should busy-wait until second writer is done"
+  );
+  let begin1Stmt = db1.createAsyncStatement("BEGIN IMMEDIATE");
+  let promise1Began = promiseExecuteStatement(begin1Stmt);
+  let update1Stmt = db1.createAsyncStatement(`UPDATE a SET b = 3 WHERE b = 1`);
+  let promise1Updated = promiseExecuteStatement(update1Stmt);
+
+  info("Wait 5 seconds");
+  await new Promise(resolve => setTimeout(resolve, 5000));
+
+  info("Commit transaction on second writer");
+  let insertIntoA2Stmt = db2.createAsyncStatement(`INSERT INTO a(b) VALUES(1)`);
+  await promiseExecuteStatement(insertIntoA2Stmt);
+  let insertIntoC2Stmt = db2.createAsyncStatement(`INSERT INTO c(d) VALUES(2)`);
+  await promiseExecuteStatement(insertIntoC2Stmt);
+  let deleteFromC2Stmt = db2.createAsyncStatement(`DELETE FROM c`);
+  await promiseExecuteStatement(deleteFromC2Stmt);
+  let commit2Stmt = db2.createAsyncStatement("COMMIT");
+  await promiseExecuteStatement(commit2Stmt);
+
+  info("Await and commit transaction on first writer");
+  await promise1Began;
+  await promise1Updated;
+
+  let commit1Stmt = db1.createAsyncStatement("COMMIT");
+  await promiseExecuteStatement(commit1Stmt);
+
+  info("Verify our writes succeeded");
+  let select1Stmt = db2.createAsyncStatement("SELECT b FROM a");
+  let rows = await promiseExecuteStatement(select1Stmt);
+  deepEqual(
+    rows.map(row => row.getResultByName("b")),
+    [2, 3]
+  );
+
+  info("Clean up");
+  for (let stmt of [
+    walStmt,
+    createAStmt,
+    createPrevAStmt,
+    createATriggerStmt,
+    attachStmt,
+    createCStmt,
+    createCTriggerStmt,
+    begin2Stmt,
+    begin1Stmt,
+    insertIntoA2Stmt,
+    insertIntoC2Stmt,
+    deleteFromC2Stmt,
+
+    commit2Stmt,
+    update1Stmt,
+    commit1Stmt,
+    select1Stmt,
+  ]) {
+    stmt.finalize();
+  }
+  await promiseClose(db1);
+  await promiseClose(db2);
+});
diff --git a/storage/test/unit/test_sqlite_secure_delete.js b/storage/test/unit/test_sqlite_secure_delete.js
new file mode 100644
index 0000000000..7beb1f1764
--- /dev/null
+++ b/storage/test/unit/test_sqlite_secure_delete.js
@@ -0,0 +1,78 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ *vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This file tests to make sure that SQLite was compiled with
+ * SQLITE_SECURE_DELETE=1.
+ */
+
+// Helper Methods
+
+/**
+ * Reads the contents of a file and returns it as a string.
+ *
+ * @param aFile
+ *        The file to return from.
+ * @return the contents of the file in the form of a string.
+ */
+function getFileContents(aFile) {
+  let fstream = Cc["@mozilla.org/network/file-input-stream;1"].createInstance(
+    Ci.nsIFileInputStream
+  );
+  fstream.init(aFile, -1, 0, 0);
+
+  let bstream = Cc["@mozilla.org/binaryinputstream;1"].createInstance(
+    Ci.nsIBinaryInputStream
+  );
+  bstream.setInputStream(fstream);
+  return bstream.readBytes(bstream.available());
+}
+
+// Tests
+
+add_test(function test_delete_removes_data() {
+  const TEST_STRING = "SomeRandomStringToFind";
+
+  let file = getTestDB();
+  let db = Services.storage.openDatabase(file);
+
+  // Create the table and insert the data.
+  db.createTable("test", "data TEXT");
+  let stmt = db.createStatement("INSERT INTO test VALUES(:data)");
+  stmt.params.data = TEST_STRING;
+  try {
+    stmt.execute();
+  } finally {
+    stmt.finalize();
+  }
+
+  // Make sure this test is actually testing what it thinks by making sure the
+  // string shows up in the database.  Because the previous statement was
+  // automatically wrapped in a transaction, the contents are already on disk.
+  let contents = getFileContents(file);
+  Assert.notEqual(-1, contents.indexOf(TEST_STRING));
+
+  // Delete the data, and then close the database.
+  stmt = db.createStatement("DELETE FROM test WHERE data = :data");
+  stmt.params.data = TEST_STRING;
+  try {
+    stmt.execute();
+  } finally {
+    stmt.finalize();
+  }
+  db.close();
+
+  // Check the file to see if the string can be found.
+  contents = getFileContents(file);
+  Assert.equal(-1, contents.indexOf(TEST_STRING));
+
+  run_next_test();
+});
+
+function run_test() {
+  cleanup();
+  run_next_test();
+}
diff --git a/storage/test/unit/test_statement_executeAsync.js b/storage/test/unit/test_statement_executeAsync.js
new file mode 100644
index 0000000000..dab15121a5
--- /dev/null
+++ b/storage/test/unit/test_statement_executeAsync.js
@@ -0,0 +1,1045 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * This file tests the functionality of mozIStorageBaseStatement::executeAsync
+ * for both mozIStorageStatement and mozIStorageAsyncStatement.
+ */
+
+// This file uses the internal _quit from testing/xpcshell/head.js */
+/* global _quit */
+
+const INTEGER = 1;
+const TEXT = "this is test text";
+const REAL = 3.23;
+const BLOB = [1, 2];
+
+/**
+ * Execute the given statement asynchronously, spinning an event loop until the
+ * async statement completes.
+ *
+ * @param aStmt
+ *        The statement to execute.
+ * @param [aOptions={}]
+ * @param [aOptions.error=false]
+ *        If true we should expect an error whose code we do not care about.  If
+ *        a numeric value, that's the error code we expect and require.  If we
+ *        are expecting an error, we expect a completion reason of REASON_ERROR.
+ *        Otherwise we expect no error notification and a completion reason of
+ *        REASON_FINISHED.
+ * @param [aOptions.cancel]
+ *        If true we cancel the pending statement and additionally return the
+ *        pending statement in case you want to further manipulate it.
+ * @param [aOptions.returnPending=false]
+ *        If true we keep the pending statement around and return it to you.  We
+ *        normally avoid doing this to try and minimize the amount of time a
+ *        reference is held to the returned pending statement.
+ * @param [aResults]
+ *        If omitted, we assume no results rows are expected.  If it is a
+ *        number, we assume it is the number of results rows expected.  If it is
+ *        a function, we assume it is a function that takes the 1) result row
+ *        number, 2) result tuple, 3) call stack for the original call to
+ *        execAsync as arguments.  If it is a list, we currently assume it is a
+ *        list of functions where each function is intended to evaluate the
+ *        result row at that ordinal position and takes the result tuple and
+ *        the call stack for the original call.
+ */
+function execAsync(aStmt, aOptions, aResults) {
+  let caller = Components.stack.caller;
+  if (aOptions == null) {
+    aOptions = {};
+  }
+
+  let resultsExpected;
+  let resultsChecker;
+  if (aResults == null) {
+    resultsExpected = 0;
+  } else if (typeof aResults == "number") {
+    resultsExpected = aResults;
+  } else if (typeof aResults == "function") {
+    resultsChecker = aResults;
+  } else {
+    // array
+    resultsExpected = aResults.length;
+    resultsChecker = function (aResultNum, aTup, aCaller) {
+      aResults[aResultNum](aTup, aCaller);
+    };
+  }
+  let resultsSeen = 0;
+
+  let errorCodeExpected = false;
+  let reasonExpected = Ci.mozIStorageStatementCallback.REASON_FINISHED;
+  let altReasonExpected = null;
+  if ("error" in aOptions) {
+    errorCodeExpected = aOptions.error;
+    if (errorCodeExpected) {
+      reasonExpected = Ci.mozIStorageStatementCallback.REASON_ERROR;
+    }
+  }
+  let errorCodeSeen = false;
+
+  if ("cancel" in aOptions && aOptions.cancel) {
+    altReasonExpected = Ci.mozIStorageStatementCallback.REASON_CANCELED;
+  }
+
+  let completed = false;
+
+  let listener = {
+    handleResult(aResultSet) {
+      let row,
+        resultsSeenThisCall = 0;
+      while ((row = aResultSet.getNextRow()) != null) {
+        if (resultsChecker) {
+          resultsChecker(resultsSeen, row, caller);
+        }
+        resultsSeen++;
+        resultsSeenThisCall++;
+      }
+
+      if (!resultsSeenThisCall) {
+        do_throw("handleResult invoked with 0 result rows!");
+      }
+    },
+    handleError(aError) {
+      if (errorCodeSeen) {
+        do_throw("handleError called when we already had an error!");
+      }
+      errorCodeSeen = aError.result;
+    },
+    handleCompletion(aReason) {
+      if (completed) {
+        // paranoia check
+        do_throw("Received a second handleCompletion notification!", caller);
+      }
+
+      if (resultsSeen != resultsExpected) {
+        do_throw(
+          "Expected " +
+            resultsExpected +
+            " rows of results but " +
+            "got " +
+            resultsSeen +
+            " rows!",
+          caller
+        );
+      }
+
+      if (errorCodeExpected && !errorCodeSeen) {
+        do_throw("Expected an error, but did not see one.", caller);
+      } else if (errorCodeExpected != errorCodeSeen) {
+        do_throw(
+          "Expected error code " +
+            errorCodeExpected +
+            " but got " +
+            errorCodeSeen,
+          caller
+        );
+      }
+
+      if (aReason != reasonExpected && aReason != altReasonExpected) {
+        do_throw(
+          "Expected reason " +
+            reasonExpected +
+            (altReasonExpected ? " or " + altReasonExpected : "") +
+            " but got " +
+            aReason,
+          caller
+        );
+      }
+
+      completed = true;
+    },
+  };
+
+  let pending;
+  // Only get a pending reference if we're supposed to do.
+  // (note: This does not stop XPConnect from holding onto one currently.)
+  if (
+    ("cancel" in aOptions && aOptions.cancel) ||
+    ("returnPending" in aOptions && aOptions.returnPending)
+  ) {
+    pending = aStmt.executeAsync(listener);
+  } else {
+    aStmt.executeAsync(listener);
+  }
+
+  if ("cancel" in aOptions && aOptions.cancel) {
+    pending.cancel();
+  }
+
+  Services.tm.spinEventLoopUntil(
+    "Test(test_statement_executeAsync.js:execAsync)",
+    () => completed || _quit
+  );
+
+  return pending;
+}
+
+/**
+ * Make sure that illegal SQL generates the expected runtime error and does not
+ * result in any crashes.  Async-only since the synchronous case generates the
+ * error synchronously (and is tested elsewhere).
+ */
+function test_illegal_sql_async_deferred() {
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(QUERY_HISTOGRAM);
+
+  // gibberish
+  let stmt = makeTestStatement("I AM A ROBOT. DO AS I SAY.");
+  execAsync(stmt, { error: Ci.mozIStorageError.ERROR });
+  stmt.finalize();
+
+  TelemetryTestUtils.assertKeyedHistogramValue(
+    histogram,
+    TEST_DB_NAME,
+    TELEMETRY_VALUES.failure,
+    1
+  );
+  histogram.clear();
+
+  // legal SQL syntax, but with semantics issues.
+  stmt = makeTestStatement("SELECT destination FROM funkytown");
+  execAsync(stmt, { error: Ci.mozIStorageError.ERROR });
+  stmt.finalize();
+
+  TelemetryTestUtils.assertKeyedHistogramValue(
+    histogram,
+    TEST_DB_NAME,
+    TELEMETRY_VALUES.failure,
+    1
+  );
+  histogram.clear();
+
+  run_next_test();
+}
+test_illegal_sql_async_deferred.asyncOnly = true;
+
+function test_create_table() {
+  // Ensure our table doesn't exist
+  Assert.ok(!getOpenedDatabase().tableExists("test"));
+
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(QUERY_HISTOGRAM);
+
+  var stmt = makeTestStatement(
+    "CREATE TABLE test (" +
+      "id INTEGER, " +
+      "string TEXT, " +
+      "number REAL, " +
+      "nuller NULL, " +
+      "blober BLOB" +
+      ")"
+  );
+  execAsync(stmt);
+  stmt.finalize();
+
+  TelemetryTestUtils.assertKeyedHistogramValue(
+    histogram,
+    TEST_DB_NAME,
+    TELEMETRY_VALUES.success,
+    1
+  );
+  histogram.clear();
+
+  // Check that the table has been created
+  Assert.ok(getOpenedDatabase().tableExists("test"));
+
+  histogram.clear();
+
+  // Verify that it's created correctly (this will throw if it wasn't)
+  let checkStmt = getOpenedDatabase().createStatement(
+    "SELECT id, string, number, nuller, blober FROM test"
+  );
+  checkStmt.finalize();
+
+  // Nothing has executed so the histogram should be empty.
+  Assert.ok(!histogram.snapshot().values);
+
+  run_next_test();
+}
+
+function test_add_data() {
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(QUERY_HISTOGRAM);
+
+  var stmt = makeTestStatement(
+    "INSERT INTO test (id, string, number, nuller, blober) " +
+      "VALUES (?, ?, ?, ?, ?)"
+  );
+  stmt.bindBlobByIndex(4, BLOB, BLOB.length);
+  stmt.bindByIndex(3, null);
+  stmt.bindByIndex(2, REAL);
+  stmt.bindByIndex(1, TEXT);
+  stmt.bindByIndex(0, INTEGER);
+
+  execAsync(stmt);
+  stmt.finalize();
+
+  TelemetryTestUtils.assertKeyedHistogramValue(
+    histogram,
+    TEST_DB_NAME,
+    TELEMETRY_VALUES.success,
+    1
+  );
+  histogram.clear();
+
+  // Check that the result is in the table
+  verifyQuery(
+    "SELECT string, number, nuller, blober FROM test WHERE id = ?",
+    INTEGER,
+    [TEXT, REAL, null, BLOB]
+  );
+
+  TelemetryTestUtils.assertKeyedHistogramValue(
+    histogram,
+    TEST_DB_NAME,
+    TELEMETRY_VALUES.success,
+    1
+  );
+  histogram.clear();
+
+  run_next_test();
+}
+
+function test_get_data() {
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(QUERY_HISTOGRAM);
+
+  var stmt = makeTestStatement(
+    "SELECT string, number, nuller, blober, id FROM test WHERE id = ?"
+  );
+  stmt.bindByIndex(0, INTEGER);
+  execAsync(stmt, {}, [
+    function (tuple) {
+      Assert.notEqual(null, tuple);
+
+      // Check that it's what we expect
+      Assert.ok(!tuple.getIsNull(0));
+      Assert.equal(tuple.getResultByName("string"), tuple.getResultByIndex(0));
+      Assert.equal(TEXT, tuple.getResultByName("string"));
+      Assert.equal(
+        Ci.mozIStorageValueArray.VALUE_TYPE_TEXT,
+        tuple.getTypeOfIndex(0)
+      );
+
+      Assert.ok(!tuple.getIsNull(1));
+      Assert.equal(tuple.getResultByName("number"), tuple.getResultByIndex(1));
+      Assert.equal(REAL, tuple.getResultByName("number"));
+      Assert.equal(
+        Ci.mozIStorageValueArray.VALUE_TYPE_FLOAT,
+        tuple.getTypeOfIndex(1)
+      );
+
+      Assert.ok(tuple.getIsNull(2));
+      Assert.equal(tuple.getResultByName("nuller"), tuple.getResultByIndex(2));
+      Assert.equal(null, tuple.getResultByName("nuller"));
+      Assert.equal(
+        Ci.mozIStorageValueArray.VALUE_TYPE_NULL,
+        tuple.getTypeOfIndex(2)
+      );
+
+      Assert.ok(!tuple.getIsNull(3));
+      var blobByName = tuple.getResultByName("blober");
+      Assert.equal(BLOB.length, blobByName.length);
+      var blobByIndex = tuple.getResultByIndex(3);
+      Assert.equal(BLOB.length, blobByIndex.length);
+      for (let i = 0; i < BLOB.length; i++) {
+        Assert.equal(BLOB[i], blobByName[i]);
+        Assert.equal(BLOB[i], blobByIndex[i]);
+      }
+      var count = { value: 0 };
+      var blob = { value: null };
+      tuple.getBlob(3, count, blob);
+      Assert.equal(BLOB.length, count.value);
+      for (let i = 0; i < BLOB.length; i++) {
+        Assert.equal(BLOB[i], blob.value[i]);
+      }
+      Assert.equal(
+        Ci.mozIStorageValueArray.VALUE_TYPE_BLOB,
+        tuple.getTypeOfIndex(3)
+      );
+
+      Assert.ok(!tuple.getIsNull(4));
+      Assert.equal(tuple.getResultByName("id"), tuple.getResultByIndex(4));
+      Assert.equal(INTEGER, tuple.getResultByName("id"));
+      Assert.equal(
+        Ci.mozIStorageValueArray.VALUE_TYPE_INTEGER,
+        tuple.getTypeOfIndex(4)
+      );
+    },
+  ]);
+  stmt.finalize();
+
+  TelemetryTestUtils.assertKeyedHistogramValue(
+    histogram,
+    TEST_DB_NAME,
+    TELEMETRY_VALUES.success,
+    1
+  );
+  histogram.clear();
+
+  run_next_test();
+}
+
+function test_tuple_out_of_bounds() {
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(QUERY_HISTOGRAM);
+
+  var stmt = makeTestStatement("SELECT string FROM test");
+  execAsync(stmt, {}, [
+    function (tuple) {
+      Assert.notEqual(null, tuple);
+
+      // Check all out of bounds - should throw
+      var methods = [
+        "getTypeOfIndex",
+        "getInt32",
+        "getInt64",
+        "getDouble",
+        "getUTF8String",
+        "getString",
+        "getIsNull",
+      ];
+      for (var i in methods) {
+        try {
+          tuple[methods[i]](tuple.numEntries);
+          do_throw("did not throw :(");
+        } catch (e) {
+          Assert.equal(Cr.NS_ERROR_ILLEGAL_VALUE, e.result);
+        }
+      }
+
+      // getBlob requires more args...
+      try {
+        var blob = { value: null };
+        var size = { value: 0 };
+        tuple.getBlob(tuple.numEntries, blob, size);
+        do_throw("did not throw :(");
+      } catch (e) {
+        Assert.equal(Cr.NS_ERROR_ILLEGAL_VALUE, e.result);
+      }
+    },
+  ]);
+  stmt.finalize();
+
+  TelemetryTestUtils.assertKeyedHistogramValue(
+    histogram,
+    TEST_DB_NAME,
+    TELEMETRY_VALUES.success,
+    1
+  );
+  histogram.clear();
+
+  run_next_test();
+}
+
+function test_no_listener_works_on_success() {
+  var stmt = makeTestStatement("DELETE FROM test WHERE id = ?");
+  stmt.bindByIndex(0, 0);
+  stmt.executeAsync();
+  stmt.finalize();
+
+  // Run the next test.
+  run_next_test();
+}
+
+function test_no_listener_works_on_results() {
+  var stmt = makeTestStatement("SELECT ?");
+  stmt.bindByIndex(0, 1);
+  stmt.executeAsync();
+  stmt.finalize();
+
+  // Run the next test.
+  run_next_test();
+}
+
+function test_no_listener_works_on_error() {
+  // commit without a transaction will trigger an error
+  var stmt = makeTestStatement("COMMIT");
+  stmt.executeAsync();
+  stmt.finalize();
+
+  // Run the next test.
+  run_next_test();
+}
+
+function test_partial_listener_works() {
+  var stmt = makeTestStatement("DELETE FROM test WHERE id = ?");
+  stmt.bindByIndex(0, 0);
+  stmt.executeAsync({
+    handleResult(aResultSet) {},
+  });
+  stmt.executeAsync({
+    handleError(aError) {},
+  });
+  stmt.executeAsync({
+    handleCompletion(aReason) {},
+  });
+  stmt.finalize();
+
+  // Run the next test.
+  run_next_test();
+}
+
+/**
+ * Dubious cancellation test that depends on system loading may or may not
+ * succeed in canceling things.  It does at least test if calling cancel blows
+ * up.  test_AsyncCancellation in test_true_async.cpp is our test that canceling
+ * actually works correctly.
+ */
+function test_immediate_cancellation() {
+  var stmt = makeTestStatement("DELETE FROM test WHERE id = ?");
+  stmt.bindByIndex(0, 0);
+  execAsync(stmt, { cancel: true });
+  stmt.finalize();
+  run_next_test();
+}
+
+/**
+ * Test that calling cancel twice throws the second time.
+ */
+function test_double_cancellation() {
+  var stmt = makeTestStatement("DELETE FROM test WHERE id = ?");
+  stmt.bindByIndex(0, 0);
+  let pendingStatement = execAsync(stmt, { cancel: true });
+  // And cancel again - expect an exception
+  expectError(Cr.NS_ERROR_UNEXPECTED, () => pendingStatement.cancel());
+
+  stmt.finalize();
+  run_next_test();
+}
+
+/**
+ * Verify that nothing untoward happens if we try and cancel something after it
+ * has fully run to completion.
+ */
+function test_cancellation_after_execution() {
+  var stmt = makeTestStatement("DELETE FROM test WHERE id = ?");
+  stmt.bindByIndex(0, 0);
+  let pendingStatement = execAsync(stmt, { returnPending: true });
+  // (the statement has fully executed at this point)
+  // canceling after the statement has run to completion should not throw!
+  pendingStatement.cancel();
+
+  stmt.finalize();
+  run_next_test();
+}
+
+/**
+ * Verifies that a single statement can be executed more than once.  Might once
+ * have been intended to also ensure that callback notifications were not
+ * incorrectly interleaved, but that part was brittle (it's totally fine for
+ * handleResult to get called multiple times) and not comprehensive.
+ */
+function test_double_execute() {
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(QUERY_HISTOGRAM);
+
+  var stmt = makeTestStatement("SELECT 1");
+  execAsync(stmt, null, 1);
+  execAsync(stmt, null, 1);
+  stmt.finalize();
+
+  TelemetryTestUtils.assertKeyedHistogramValue(
+    histogram,
+    TEST_DB_NAME,
+    TELEMETRY_VALUES.success,
+    2
+  );
+  histogram.clear();
+
+  run_next_test();
+}
+
+function test_finalized_statement_does_not_crash() {
+  var stmt = makeTestStatement("SELECT * FROM TEST");
+  stmt.finalize();
+  // we are concerned about a crash here; an error is fine.
+  try {
+    stmt.executeAsync();
+  } catch (ex) {
+    // Do nothing.
+  }
+
+  // Run the next test.
+  run_next_test();
+}
+
+/**
+ * Bind by mozIStorageBindingParams on the mozIStorageBaseStatement by index.
+ */
+function test_bind_direct_binding_params_by_index() {
+  var stmt = makeTestStatement(
+    "INSERT INTO test (id, string, number, nuller, blober) " +
+      "VALUES (?, ?, ?, ?, ?)"
+  );
+  let insertId = nextUniqueId++;
+  stmt.bindByIndex(0, insertId);
+  stmt.bindByIndex(1, TEXT);
+  stmt.bindByIndex(2, REAL);
+  stmt.bindByIndex(3, null);
+  stmt.bindBlobByIndex(4, BLOB, BLOB.length);
+  execAsync(stmt);
+  stmt.finalize();
+  verifyQuery(
+    "SELECT string, number, nuller, blober FROM test WHERE id = ?",
+    insertId,
+    [TEXT, REAL, null, BLOB]
+  );
+  run_next_test();
+}
+
+/**
+ * Bind by mozIStorageBindingParams on the mozIStorageBaseStatement by name.
+ */
+function test_bind_direct_binding_params_by_name() {
+  var stmt = makeTestStatement(
+    "INSERT INTO test (id, string, number, nuller, blober) " +
+      "VALUES (:int, :text, :real, :null, :blob)"
+  );
+  let insertId = nextUniqueId++;
+  stmt.bindByName("int", insertId);
+  stmt.bindByName("text", TEXT);
+  stmt.bindByName("real", REAL);
+  stmt.bindByName("null", null);
+  stmt.bindBlobByName("blob", BLOB);
+  execAsync(stmt);
+  stmt.finalize();
+  verifyQuery(
+    "SELECT string, number, nuller, blober FROM test WHERE id = ?",
+    insertId,
+    [TEXT, REAL, null, BLOB]
+  );
+  run_next_test();
+}
+
+function test_bind_js_params_helper_by_index() {
+  var stmt = makeTestStatement(
+    "INSERT INTO test (id, string, number, nuller, blober) " +
+      "VALUES (?, ?, ?, ?, NULL)"
+  );
+  let insertId = nextUniqueId++;
+  // we cannot bind blobs this way; no blober
+  stmt.params[3] = null;
+  stmt.params[2] = REAL;
+  stmt.params[1] = TEXT;
+  stmt.params[0] = insertId;
+  execAsync(stmt);
+  stmt.finalize();
+  verifyQuery(
+    "SELECT string, number, nuller FROM test WHERE id = ?",
+    insertId,
+    [TEXT, REAL, null]
+  );
+  run_next_test();
+}
+
+function test_bind_js_params_helper_by_name() {
+  var stmt = makeTestStatement(
+    "INSERT INTO test (id, string, number, nuller, blober) " +
+      "VALUES (:int, :text, :real, :null, NULL)"
+  );
+  let insertId = nextUniqueId++;
+  // we cannot bind blobs this way; no blober
+  stmt.params.null = null;
+  stmt.params.real = REAL;
+  stmt.params.text = TEXT;
+  stmt.params.int = insertId;
+  execAsync(stmt);
+  stmt.finalize();
+  verifyQuery(
+    "SELECT string, number, nuller FROM test WHERE id = ?",
+    insertId,
+    [TEXT, REAL, null]
+  );
+  run_next_test();
+}
+
+function test_bind_multiple_rows_by_index() {
+  const AMOUNT_TO_ADD = 5;
+  var stmt = makeTestStatement(
+    "INSERT INTO test (id, string, number, nuller, blober) " +
+      "VALUES (?, ?, ?, ?, ?)"
+  );
+  var array = stmt.newBindingParamsArray();
+  for (let i = 0; i < AMOUNT_TO_ADD; i++) {
+    let bp = array.newBindingParams();
+    bp.bindByIndex(0, INTEGER);
+    bp.bindByIndex(1, TEXT);
+    bp.bindByIndex(2, REAL);
+    bp.bindByIndex(3, null);
+    bp.bindBlobByIndex(4, BLOB, BLOB.length);
+    array.addParams(bp);
+    Assert.equal(array.length, i + 1);
+  }
+  stmt.bindParameters(array);
+
+  let rowCount = getTableRowCount("test");
+  execAsync(stmt);
+  Assert.equal(rowCount + AMOUNT_TO_ADD, getTableRowCount("test"));
+  stmt.finalize();
+  run_next_test();
+}
+
+function test_bind_multiple_rows_by_name() {
+  const AMOUNT_TO_ADD = 5;
+  var stmt = makeTestStatement(
+    "INSERT INTO test (id, string, number, nuller, blober) " +
+      "VALUES (:int, :text, :real, :null, :blob)"
+  );
+  var array = stmt.newBindingParamsArray();
+  for (let i = 0; i < AMOUNT_TO_ADD; i++) {
+    let bp = array.newBindingParams();
+    bp.bindByName("int", INTEGER);
+    bp.bindByName("text", TEXT);
+    bp.bindByName("real", REAL);
+    bp.bindByName("null", null);
+    bp.bindBlobByName("blob", BLOB);
+    array.addParams(bp);
+    Assert.equal(array.length, i + 1);
+  }
+  stmt.bindParameters(array);
+
+  let rowCount = getTableRowCount("test");
+  execAsync(stmt);
+  Assert.equal(rowCount + AMOUNT_TO_ADD, getTableRowCount("test"));
+  stmt.finalize();
+  run_next_test();
+}
+
+/**
+ * Verify that a mozIStorageStatement instance throws immediately when we
+ * try and bind to an illegal index.
+ */
+function test_bind_out_of_bounds_sync_immediate() {
+  let stmt = makeTestStatement("INSERT INTO test (id) VALUES (?)");
+
+  let array = stmt.newBindingParamsArray();
+  let bp = array.newBindingParams();
+
+  // Check variant binding.
+  expectError(Cr.NS_ERROR_INVALID_ARG, () => bp.bindByIndex(1, INTEGER));
+  // Check blob binding.
+  expectError(Cr.NS_ERROR_INVALID_ARG, () =>
+    bp.bindBlobByIndex(1, BLOB, BLOB.length)
+  );
+
+  stmt.finalize();
+  run_next_test();
+}
+test_bind_out_of_bounds_sync_immediate.syncOnly = true;
+
+/**
+ * Verify that a mozIStorageAsyncStatement reports an error asynchronously when
+ * we bind to an illegal index.
+ */
+function test_bind_out_of_bounds_async_deferred() {
+  let stmt = makeTestStatement("INSERT INTO test (id) VALUES (?)");
+
+  let array = stmt.newBindingParamsArray();
+  let bp = array.newBindingParams();
+
+  // There is no difference between variant and blob binding for async purposes.
+  bp.bindByIndex(1, INTEGER);
+  array.addParams(bp);
+  stmt.bindParameters(array);
+  execAsync(stmt, { error: Ci.mozIStorageError.RANGE });
+
+  stmt.finalize();
+  run_next_test();
+}
+test_bind_out_of_bounds_async_deferred.asyncOnly = true;
+
+function test_bind_no_such_name_sync_immediate() {
+  let stmt = makeTestStatement("INSERT INTO test (id) VALUES (:foo)");
+
+  let array = stmt.newBindingParamsArray();
+  let bp = array.newBindingParams();
+
+  // Check variant binding.
+  expectError(Cr.NS_ERROR_INVALID_ARG, () =>
+    bp.bindByName("doesnotexist", INTEGER)
+  );
+  // Check blob binding.
+  expectError(Cr.NS_ERROR_INVALID_ARG, () =>
+    bp.bindBlobByName("doesnotexist", BLOB)
+  );
+
+  stmt.finalize();
+  run_next_test();
+}
+test_bind_no_such_name_sync_immediate.syncOnly = true;
+
+function test_bind_no_such_name_async_deferred() {
+  let stmt = makeTestStatement("INSERT INTO test (id) VALUES (:foo)");
+
+  let array = stmt.newBindingParamsArray();
+  let bp = array.newBindingParams();
+
+  bp.bindByName("doesnotexist", INTEGER);
+  array.addParams(bp);
+  stmt.bindParameters(array);
+  execAsync(stmt, { error: Ci.mozIStorageError.RANGE });
+
+  stmt.finalize();
+  run_next_test();
+}
+test_bind_no_such_name_async_deferred.asyncOnly = true;
+
+function test_bind_bogus_type_by_index() {
+  // We try to bind a JS Object here that should fail to bind.
+  let stmt = makeTestStatement("INSERT INTO test (blober) VALUES (?)");
+
+  let array = stmt.newBindingParamsArray();
+  let bp = array.newBindingParams();
+  Assert.throws(() => bp.bindByIndex(0, run_test), /NS_ERROR_UNEXPECTED/);
+
+  stmt.finalize();
+  run_next_test();
+}
+
+function test_bind_bogus_type_by_name() {
+  // We try to bind a JS Object here that should fail to bind.
+  let stmt = makeTestStatement("INSERT INTO test (blober) VALUES (:blob)");
+
+  let array = stmt.newBindingParamsArray();
+  let bp = array.newBindingParams();
+  Assert.throws(() => bp.bindByName("blob", run_test), /NS_ERROR_UNEXPECTED/);
+
+  stmt.finalize();
+  run_next_test();
+}
+
+function test_bind_params_already_locked() {
+  let stmt = makeTestStatement("INSERT INTO test (id) VALUES (:int)");
+
+  let array = stmt.newBindingParamsArray();
+  let bp = array.newBindingParams();
+  bp.bindByName("int", INTEGER);
+  array.addParams(bp);
+
+  // We should get an error after we call addParams and try to bind again.
+  expectError(Cr.NS_ERROR_UNEXPECTED, () => bp.bindByName("int", INTEGER));
+
+  stmt.finalize();
+  run_next_test();
+}
+
+function test_bind_params_array_already_locked() {
+  let stmt = makeTestStatement("INSERT INTO test (id) VALUES (:int)");
+
+  let array = stmt.newBindingParamsArray();
+  let bp1 = array.newBindingParams();
+  bp1.bindByName("int", INTEGER);
+  array.addParams(bp1);
+  let bp2 = array.newBindingParams();
+  stmt.bindParameters(array);
+  bp2.bindByName("int", INTEGER);
+
+  // We should get an error after we have bound the array to the statement.
+  expectError(Cr.NS_ERROR_UNEXPECTED, () => array.addParams(bp2));
+
+  stmt.finalize();
+  run_next_test();
+}
+
+function test_no_binding_params_from_locked_array() {
+  let stmt = makeTestStatement("INSERT INTO test (id) VALUES (:int)");
+
+  let array = stmt.newBindingParamsArray();
+  let bp = array.newBindingParams();
+  bp.bindByName("int", INTEGER);
+  array.addParams(bp);
+  stmt.bindParameters(array);
+
+  // We should not be able to get a new BindingParams object after we have bound
+  // to the statement.
+  expectError(Cr.NS_ERROR_UNEXPECTED, () => array.newBindingParams());
+
+  stmt.finalize();
+  run_next_test();
+}
+
+function test_not_right_owning_array() {
+  let stmt = makeTestStatement("INSERT INTO test (id) VALUES (:int)");
+
+  let array1 = stmt.newBindingParamsArray();
+  let array2 = stmt.newBindingParamsArray();
+  let bp = array1.newBindingParams();
+  bp.bindByName("int", INTEGER);
+
+  // We should not be able to add bp to array2 since it was created from array1.
+  expectError(Cr.NS_ERROR_UNEXPECTED, () => array2.addParams(bp));
+
+  stmt.finalize();
+  run_next_test();
+}
+
+function test_not_right_owning_statement() {
+  let stmt1 = makeTestStatement("INSERT INTO test (id) VALUES (:int)");
+  let stmt2 = makeTestStatement("INSERT INTO test (id) VALUES (:int)");
+
+  let array1 = stmt1.newBindingParamsArray();
+  stmt2.newBindingParamsArray();
+  let bp = array1.newBindingParams();
+  bp.bindByName("int", INTEGER);
+  array1.addParams(bp);
+
+  // We should not be able to bind array1 since it was created from stmt1.
+  expectError(Cr.NS_ERROR_UNEXPECTED, () => stmt2.bindParameters(array1));
+
+  stmt1.finalize();
+  stmt2.finalize();
+  run_next_test();
+}
+
+function test_bind_empty_array() {
+  let stmt = makeTestStatement("INSERT INTO test (id) VALUES (:int)");
+
+  let paramsArray = stmt.newBindingParamsArray();
+
+  // We should not be able to bind this array to the statement because it is
+  // empty.
+  expectError(Cr.NS_ERROR_UNEXPECTED, () => stmt.bindParameters(paramsArray));
+
+  stmt.finalize();
+  run_next_test();
+}
+
+function test_multiple_results() {
+  let expectedResults = getTableRowCount("test");
+  // Sanity check - we should have more than one result, but let's be sure.
+  Assert.ok(expectedResults > 1);
+
+  // Now check that we get back two rows of data from our async query.
+  let stmt = makeTestStatement("SELECT * FROM test");
+  execAsync(stmt, {}, expectedResults);
+
+  stmt.finalize();
+  run_next_test();
+}
+
+// Test Runner
+
+const TEST_PASS_SYNC = 0;
+const TEST_PASS_ASYNC = 1;
+/**
+ * We run 2 passes against the test.  One where makeTestStatement generates
+ * synchronous (mozIStorageStatement) statements and one where it generates
+ * asynchronous (mozIStorageAsyncStatement) statements.
+ *
+ * Because of differences in the ability to know the number of parameters before
+ * dispatching, some tests are sync/async specific.  These functions are marked
+ * with 'syncOnly' or 'asyncOnly' attributes and run_next_test knows what to do.
+ */
+var testPass = TEST_PASS_SYNC;
+
+/**
+ * Create a statement of the type under test per testPass.
+ *
+ * @param aSQL
+ *        The SQL string from which to build a statement.
+ * @return a statement of the type under test per testPass.
+ */
+function makeTestStatement(aSQL) {
+  if (testPass == TEST_PASS_SYNC) {
+    return getOpenedDatabase().createStatement(aSQL);
+  }
+  return getOpenedDatabase().createAsyncStatement(aSQL);
+}
+
+var tests = [
+  test_illegal_sql_async_deferred,
+  test_create_table,
+  test_add_data,
+  test_get_data,
+  test_tuple_out_of_bounds,
+  test_no_listener_works_on_success,
+  test_no_listener_works_on_results,
+  test_no_listener_works_on_error,
+  test_partial_listener_works,
+  test_immediate_cancellation,
+  test_double_cancellation,
+  test_cancellation_after_execution,
+  test_double_execute,
+  test_finalized_statement_does_not_crash,
+  test_bind_direct_binding_params_by_index,
+  test_bind_direct_binding_params_by_name,
+  test_bind_js_params_helper_by_index,
+  test_bind_js_params_helper_by_name,
+  test_bind_multiple_rows_by_index,
+  test_bind_multiple_rows_by_name,
+  test_bind_out_of_bounds_sync_immediate,
+  test_bind_out_of_bounds_async_deferred,
+  test_bind_no_such_name_sync_immediate,
+  test_bind_no_such_name_async_deferred,
+  test_bind_bogus_type_by_index,
+  test_bind_bogus_type_by_name,
+  test_bind_params_already_locked,
+  test_bind_params_array_already_locked,
+  test_bind_empty_array,
+  test_no_binding_params_from_locked_array,
+  test_not_right_owning_array,
+  test_not_right_owning_statement,
+  test_multiple_results,
+];
+var index = 0;
+
+const STARTING_UNIQUE_ID = 2;
+var nextUniqueId = STARTING_UNIQUE_ID;
+
+function run_next_test() {
+  function _run_next_test() {
+    // use a loop so we can skip tests...
+    while (index < tests.length) {
+      let test = tests[index++];
+      // skip tests not appropriate to the current test pass
+      if (
+        (testPass == TEST_PASS_SYNC && "asyncOnly" in test) ||
+        (testPass == TEST_PASS_ASYNC && "syncOnly" in test)
+      ) {
+        continue;
+      }
+
+      // Asynchronous tests means that exceptions don't kill the test.
+      try {
+        print("****** Running the next test: " + test.name);
+        test();
+        return;
+      } catch (e) {
+        do_throw(e);
+      }
+    }
+
+    // if we only completed the first pass, move to the next pass
+    if (testPass == TEST_PASS_SYNC) {
+      print("********* Beginning mozIStorageAsyncStatement pass.");
+      testPass++;
+      index = 0;
+      // a new pass demands a new database
+      asyncCleanup();
+      nextUniqueId = STARTING_UNIQUE_ID;
+      _run_next_test();
+      return;
+    }
+
+    // we did some async stuff; we need to clean up.
+    asyncCleanup();
+    do_test_finished();
+  }
+
+  // Don't actually schedule another test if we're quitting.
+  if (!_quit) {
+    // For saner stacks, we execute this code RSN.
+    executeSoon(_run_next_test);
+  }
+}
+
+function run_test() {
+  // Thunderbird doesn't have one or more of the probes used in this test.
+  // Ensure the data is collected anyway.
+  Services.prefs.setBoolPref(
+    "toolkit.telemetry.testing.overrideProductsCheck",
+    true
+  );
+
+  cleanup();
+
+  do_test_pending();
+  run_next_test();
+}
diff --git a/storage/test/unit/test_statement_wrapper_automatically.js b/storage/test/unit/test_statement_wrapper_automatically.js
new file mode 100644
index 0000000000..8ff203f7c7
--- /dev/null
+++ b/storage/test/unit/test_statement_wrapper_automatically.js
@@ -0,0 +1,166 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+   vim:set ts=2 sw=2 sts=2 et:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file tests the functions of mozIStorageStatementWrapper
+
+function setup() {
+  getOpenedDatabase().createTable(
+    "test",
+    "id INTEGER PRIMARY KEY, val NONE,alt_val NONE"
+  );
+}
+
+/**
+ * A convenience wrapper for do_check_eq.  Calls do_check_eq on aActualVal
+ * and aReturnedVal, with one caveat.
+ *
+ * Date objects are converted before parameter binding to PRTime's (microsecs
+ * since epoch).  They are not reconverted when retrieved from the database.
+ * This function abstracts away this reconversion so that you can pass in,
+ * for example:
+ *
+ *   checkVal(new Date(), aReturnedVal)                    // this
+ *   checkVal(new Date().valueOf() * 1000.0, aReturnedVal) // instead of this
+ *
+ * Should any other types require conversion in the future, their conversions
+ * may also be abstracted away here.
+ *
+ * @param aActualVal
+ *        the value inserted into the database
+ * @param aReturnedVal
+ *        the value retrieved from the database
+ */
+function checkVal(aActualVal, aReturnedVal) {
+  if (aActualVal instanceof Date) {
+    aActualVal = aActualVal.valueOf() * 1000.0;
+  }
+  Assert.equal(aActualVal, aReturnedVal);
+}
+
+/**
+ * Removes all rows from our test table.
+ */
+function clearTable() {
+  var stmt = createStatement("DELETE FROM test");
+  stmt.execute();
+  stmt.finalize();
+  ensureNumRows(0);
+}
+
+/**
+ * Ensures that the number of rows in our test table is equal to aNumRows.
+ * Calls do_check_eq on aNumRows and the value retrieved by SELECT'ing COUNT(*).
+ *
+ * @param aNumRows
+ *        the number of rows our test table should contain
+ */
+function ensureNumRows(aNumRows) {
+  var stmt = createStatement("SELECT COUNT(*) AS number FROM test");
+  Assert.ok(stmt.step());
+  Assert.equal(aNumRows, stmt.row.number);
+  stmt.reset();
+  stmt.finalize();
+}
+
+/**
+ * Inserts aVal into our test table and checks that insertion was successful by
+ * retrieving the newly inserted value from the database and comparing it
+ * against aVal.  aVal is bound to a single parameter.
+ *
+ * @param aVal
+ *        value to insert into our test table and check
+ */
+function insertAndCheckSingleParam(aVal) {
+  clearTable();
+
+  var stmt = createStatement("INSERT INTO test (val) VALUES (:val)");
+  stmt.params.val = aVal;
+  stmt.execute();
+  stmt.finalize();
+
+  ensureNumRows(1);
+
+  stmt = createStatement("SELECT val FROM test WHERE id = 1");
+  Assert.ok(stmt.step());
+  checkVal(aVal, stmt.row.val);
+  stmt.reset();
+  stmt.finalize();
+}
+
+/**
+ * Inserts aVal into our test table and checks that insertion was successful by
+ * retrieving the newly inserted value from the database and comparing it
+ * against aVal.  aVal is bound to two separate parameters, both of which are
+ * checked against aVal.
+ *
+ * @param aVal
+ *        value to insert into our test table and check
+ */
+function insertAndCheckMultipleParams(aVal) {
+  clearTable();
+
+  var stmt = createStatement(
+    "INSERT INTO test (val, alt_val) VALUES (:val, :val)"
+  );
+  stmt.params.val = aVal;
+  stmt.execute();
+  stmt.finalize();
+
+  ensureNumRows(1);
+
+  stmt = createStatement("SELECT val, alt_val FROM test WHERE id = 1");
+  Assert.ok(stmt.step());
+  checkVal(aVal, stmt.row.val);
+  checkVal(aVal, stmt.row.alt_val);
+  stmt.reset();
+  stmt.finalize();
+}
+
+/**
+ * A convenience function that prints out a description of aVal using
+ * aVal.toString and aVal.toSource.  Output is useful when the test fails.
+ *
+ * @param aVal
+ *        a value inserted or to be inserted into our test table
+ */
+function printValDesc(aVal) {
+  try {
+    var toSource = aVal.toSource();
+  } catch (ex) {
+    toSource = "";
+  }
+  print(
+    "Testing value: toString=" +
+      aVal +
+      (toSource ? " toSource=" + toSource : "")
+  );
+}
+
+function run_test() {
+  setup();
+
+  // function JSValStorageStatementBinder in
+  // storage/mozStorageStatementParams.cpp tells us that the following types
+  // and only the following types are valid as statement parameters:
+  var vals = [
+    1337, // int
+    3.1337, // double
+    "foo", // string
+    true, // boolean
+    null, // null
+    new Date(), // Date object
+  ];
+
+  vals.forEach(function (val) {
+    printValDesc(val);
+    print("Single parameter");
+    insertAndCheckSingleParam(val);
+    print("Multiple parameters");
+    insertAndCheckMultipleParams(val);
+  });
+
+  cleanup();
+}
diff --git a/storage/test/unit/test_storage_connection.js b/storage/test/unit/test_storage_connection.js
new file mode 100644
index 0000000000..e7175a9613
--- /dev/null
+++ b/storage/test/unit/test_storage_connection.js
@@ -0,0 +1,997 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file tests the functions of mozIStorageConnection
+
+function fetchAllNames(conn) {
+  let names = [];
+  let stmt = conn.createStatement(`SELECT name FROM test ORDER BY name`);
+  while (stmt.executeStep()) {
+    names.push(stmt.getUTF8String(0));
+  }
+  stmt.finalize();
+  return names;
+}
+
+// Test Functions
+
+add_task(async function test_connectionReady_open() {
+  // there doesn't seem to be a way for the connection to not be ready (unless
+  // we close it with mozIStorageConnection::Close(), but we don't for this).
+  // It can only fail if GetPath fails on the database file, or if we run out
+  // of memory trying to use an in-memory database
+
+  var msc = getOpenedDatabase();
+  Assert.ok(msc.connectionReady);
+});
+
+add_task(async function test_connectionReady_closed() {
+  // This also tests mozIStorageConnection::Close()
+
+  var msc = getOpenedDatabase();
+  msc.close();
+  Assert.ok(!msc.connectionReady);
+  gDBConn = null; // this is so later tests don't start to fail.
+});
+
+add_task(async function test_databaseFile() {
+  var msc = getOpenedDatabase();
+  Assert.ok(getTestDB().equals(msc.databaseFile));
+});
+
+add_task(async function test_tableExists_not_created() {
+  var msc = getOpenedDatabase();
+  Assert.ok(!msc.tableExists("foo"));
+});
+
+add_task(async function test_indexExists_not_created() {
+  var msc = getOpenedDatabase();
+  Assert.ok(!msc.indexExists("foo"));
+});
+
+add_task(async function test_temp_tableExists_and_indexExists() {
+  var msc = getOpenedDatabase();
+  msc.executeSimpleSQL(
+    "CREATE TEMP TABLE test_temp(id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT)"
+  );
+  Assert.ok(msc.tableExists("test_temp"));
+
+  msc.executeSimpleSQL("CREATE INDEX test_temp_ind ON test_temp (name)");
+  Assert.ok(msc.indexExists("test_temp_ind"));
+
+  msc.executeSimpleSQL("DROP INDEX test_temp_ind");
+  msc.executeSimpleSQL("DROP TABLE test_temp");
+});
+
+add_task(async function test_createTable_not_created() {
+  var msc = getOpenedDatabase();
+  msc.createTable("test", "id INTEGER PRIMARY KEY, name TEXT");
+  Assert.ok(msc.tableExists("test"));
+});
+
+add_task(async function test_indexExists_created() {
+  var msc = getOpenedDatabase();
+  msc.executeSimpleSQL("CREATE INDEX name_ind ON test (name)");
+  Assert.ok(msc.indexExists("name_ind"));
+});
+
+add_task(async function test_createTable_already_created() {
+  var msc = getOpenedDatabase();
+  Assert.ok(msc.tableExists("test"));
+  Assert.throws(
+    () => msc.createTable("test", "id INTEGER PRIMARY KEY, name TEXT"),
+    /NS_ERROR_FAILURE/
+  );
+});
+
+add_task(async function test_attach_createTable_tableExists_indexExists() {
+  var msc = getOpenedDatabase();
+  var file = do_get_file("storage_attach.sqlite", true);
+  var msc2 = getDatabase(file);
+  msc.executeSimpleSQL("ATTACH DATABASE '" + file.path + "' AS sample");
+
+  Assert.ok(!msc.tableExists("sample.test"));
+  msc.createTable("sample.test", "id INTEGER PRIMARY KEY, name TEXT");
+  Assert.ok(msc.tableExists("sample.test"));
+  Assert.throws(
+    () => msc.createTable("sample.test", "id INTEGER PRIMARY KEY, name TEXT"),
+    /NS_ERROR_FAILURE/
+  );
+
+  Assert.ok(!msc.indexExists("sample.test_ind"));
+  msc.executeSimpleSQL("CREATE INDEX sample.test_ind ON test (name)");
+  Assert.ok(msc.indexExists("sample.test_ind"));
+
+  msc.executeSimpleSQL("DETACH DATABASE sample");
+  msc2.close();
+  try {
+    file.remove(false);
+  } catch (e) {
+    // Do nothing.
+  }
+});
+
+add_task(async function test_lastInsertRowID() {
+  var msc = getOpenedDatabase();
+  msc.executeSimpleSQL("INSERT INTO test (name) VALUES ('foo')");
+  Assert.equal(1, msc.lastInsertRowID);
+});
+
+add_task(async function test_transactionInProgress_no() {
+  var msc = getOpenedDatabase();
+  Assert.ok(!msc.transactionInProgress);
+});
+
+add_task(async function test_transactionInProgress_yes() {
+  var msc = getOpenedDatabase();
+  msc.beginTransaction();
+  Assert.ok(msc.transactionInProgress);
+  msc.commitTransaction();
+  Assert.ok(!msc.transactionInProgress);
+
+  msc.beginTransaction();
+  Assert.ok(msc.transactionInProgress);
+  msc.rollbackTransaction();
+  Assert.ok(!msc.transactionInProgress);
+});
+
+add_task(async function test_commitTransaction_no_transaction() {
+  var msc = getOpenedDatabase();
+  Assert.ok(!msc.transactionInProgress);
+  Assert.throws(() => msc.commitTransaction(), /NS_ERROR_UNEXPECTED/);
+});
+
+add_task(async function test_rollbackTransaction_no_transaction() {
+  var msc = getOpenedDatabase();
+  Assert.ok(!msc.transactionInProgress);
+  Assert.throws(() => msc.rollbackTransaction(), /NS_ERROR_UNEXPECTED/);
+});
+
+add_task(async function test_get_schemaVersion_not_set() {
+  Assert.equal(0, getOpenedDatabase().schemaVersion);
+});
+
+add_task(async function test_set_schemaVersion() {
+  var msc = getOpenedDatabase();
+  const version = 1;
+  msc.schemaVersion = version;
+  Assert.equal(version, msc.schemaVersion);
+});
+
+add_task(async function test_set_schemaVersion_same() {
+  var msc = getOpenedDatabase();
+  const version = 1;
+  msc.schemaVersion = version; // should still work ok
+  Assert.equal(version, msc.schemaVersion);
+});
+
+add_task(async function test_set_schemaVersion_negative() {
+  var msc = getOpenedDatabase();
+  const version = -1;
+  msc.schemaVersion = version;
+  Assert.equal(version, msc.schemaVersion);
+});
+
+add_task(async function test_createTable() {
+  var temp = getTestDB().parent;
+  temp.append("test_db_table");
+  try {
+    var con = Services.storage.openDatabase(temp);
+    con.createTable("a", "");
+  } catch (e) {
+    if (temp.exists()) {
+      try {
+        temp.remove(false);
+      } catch (e2) {
+        // Do nothing.
+      }
+    }
+    Assert.ok(
+      e.result == Cr.NS_ERROR_NOT_INITIALIZED || e.result == Cr.NS_ERROR_FAILURE
+    );
+  } finally {
+    if (con) {
+      con.close();
+    }
+  }
+});
+
+add_task(async function test_defaultSynchronousAtNormal() {
+  getOpenedDatabase();
+  var stmt = createStatement("PRAGMA synchronous;");
+  try {
+    stmt.executeStep();
+    Assert.equal(1, stmt.getInt32(0));
+  } finally {
+    stmt.reset();
+    stmt.finalize();
+  }
+});
+
+// must be ran before executeAsync tests
+add_task(async function test_close_does_not_spin_event_loop() {
+  // We want to make sure that the event loop on the calling thread does not
+  // spin when close is called.
+  let event = {
+    ran: false,
+    run() {
+      this.ran = true;
+    },
+  };
+
+  // Post the event before we call close, so it would run if the event loop was
+  // spun during close.
+  Services.tm.dispatchToMainThread(event);
+
+  // Sanity check, then close the database.  Afterwards, we should not have ran!
+  Assert.ok(!event.ran);
+  getOpenedDatabase().close();
+  Assert.ok(!event.ran);
+
+  // Reset gDBConn so that later tests will get a new connection object.
+  gDBConn = null;
+});
+
+add_task(
+  async function test_asyncClose_succeeds_with_finalized_async_statement() {
+    // XXX this test isn't perfect since we can't totally control when events will
+    //     run.  If this paticular function fails randomly, it means we have a
+    //     real bug.
+
+    // We want to make sure we create a cached async statement to make sure that
+    // when we finalize our statement, we end up finalizing the async one too so
+    // close will succeed.
+    let stmt = createStatement("SELECT * FROM test");
+    stmt.executeAsync();
+    stmt.finalize();
+
+    await asyncClose(getOpenedDatabase());
+    // Reset gDBConn so that later tests will get a new connection object.
+    gDBConn = null;
+  }
+);
+
+// Would assert on debug builds.
+if (!AppConstants.DEBUG) {
+  add_task(async function test_close_then_release_statement() {
+    // Testing the behavior in presence of a bad client that finalizes
+    // statements after the database has been closed (typically by
+    // letting the gc finalize the statement).
+    let db = getOpenedDatabase();
+    let stmt = createStatement(
+      "SELECT * FROM test -- test_close_then_release_statement"
+    );
+    db.close();
+    stmt.finalize(); // Finalize too late - this should not crash
+
+    // Reset gDBConn so that later tests will get a new connection object.
+    gDBConn = null;
+  });
+
+  add_task(async function test_asyncClose_then_release_statement() {
+    // Testing the behavior in presence of a bad client that finalizes
+    // statements after the database has been async closed (typically by
+    // letting the gc finalize the statement).
+    let db = getOpenedDatabase();
+    let stmt = createStatement(
+      "SELECT * FROM test -- test_asyncClose_then_release_statement"
+    );
+    await asyncClose(db);
+    stmt.finalize(); // Finalize too late - this should not crash
+
+    // Reset gDBConn so that later tests will get a new connection object.
+    gDBConn = null;
+  });
+}
+
+// In debug builds this would cause a fatal assertion.
+if (!AppConstants.DEBUG) {
+  add_task(async function test_close_fails_with_async_statement_ran() {
+    let stmt = createStatement("SELECT * FROM test");
+    stmt.executeAsync();
+    stmt.finalize();
+
+    let db = getOpenedDatabase();
+    Assert.throws(() => db.close(), /NS_ERROR_UNEXPECTED/);
+    // Reset gDBConn so that later tests will get a new connection object.
+    gDBConn = null;
+  });
+}
+
+add_task(async function test_clone_optional_param() {
+  let db1 = Services.storage.openUnsharedDatabase(getTestDB());
+  let db2 = db1.clone();
+  Assert.ok(db2.connectionReady);
+
+  // A write statement should not fail here.
+  let stmt = db2.createStatement("INSERT INTO test (name) VALUES (:name)");
+  stmt.params.name = "dwitte";
+  stmt.execute();
+  stmt.finalize();
+
+  // And a read statement should succeed.
+  stmt = db2.createStatement("SELECT * FROM test");
+  Assert.ok(stmt.executeStep());
+  stmt.finalize();
+
+  // Additionally check that it is a connection on the same database.
+  Assert.ok(db1.databaseFile.equals(db2.databaseFile));
+
+  db1.close();
+  db2.close();
+});
+
+async function standardAsyncTest(promisedDB, name, shouldInit = false) {
+  info("Performing standard async test " + name);
+
+  let adb = await promisedDB;
+  Assert.ok(adb instanceof Ci.mozIStorageAsyncConnection);
+  Assert.ok(adb instanceof Ci.mozIStorageConnection);
+
+  if (shouldInit) {
+    let stmt = adb.createAsyncStatement("CREATE TABLE test(name TEXT)");
+    await executeAsync(stmt);
+    stmt.finalize();
+  }
+
+  // Generate a name to insert and fetch back
+  name = "worker bee " + Math.random() + " (" + name + ")";
+
+  let stmt = adb.createAsyncStatement("INSERT INTO test (name) VALUES (:name)");
+  stmt.params.name = name;
+  let result = await executeAsync(stmt);
+  info("Request complete");
+  stmt.finalize();
+  Assert.ok(Components.isSuccessCode(result));
+  info("Extracting data");
+  stmt = adb.createAsyncStatement("SELECT * FROM test");
+  let found = false;
+  await executeAsync(stmt, function (results) {
+    info("Data has been extracted");
+    for (
+      let row = results.getNextRow();
+      row != null;
+      row = results.getNextRow()
+    ) {
+      if (row.getResultByName("name") == name) {
+        found = true;
+        break;
+      }
+    }
+  });
+  Assert.ok(found);
+  stmt.finalize();
+  await asyncClose(adb);
+
+  info("Standard async test " + name + " complete");
+}
+
+add_task(async function test_open_async() {
+  await standardAsyncTest(openAsyncDatabase(getTestDB(), null), "default");
+  await standardAsyncTest(openAsyncDatabase(getTestDB()), "no optional arg");
+  await standardAsyncTest(
+    openAsyncDatabase(getTestDB(), { shared: false, interruptible: true }),
+    "non-default options"
+  );
+  await standardAsyncTest(
+    openAsyncDatabase("memory"),
+    "in-memory database",
+    true
+  );
+  await standardAsyncTest(
+    openAsyncDatabase("memory", { shared: false }),
+    "in-memory database and options",
+    true
+  );
+
+  info("Testing async opening with readonly option");
+  const impliedReadOnlyOption = { ignoreLockingMode: true };
+
+  let raised = false;
+  let adb = await openAsyncDatabase(getTestDB(), impliedReadOnlyOption);
+  let stmt = adb.createAsyncStatement("CREATE TABLE test(name TEXT)");
+  try {
+    await executeAsync(stmt); // This should throw
+  } catch (e) {
+    raised = true;
+  } finally {
+    if (stmt) {
+      stmt.finalize();
+    }
+    if (adb) {
+      await asyncClose(adb);
+    }
+  }
+
+  Assert.ok(raised);
+});
+
+add_task(async function test_async_open_with_shared_cache() {
+  info("Testing that opening with a shared cache doesn't break stuff");
+  let adb = await openAsyncDatabase(getTestDB(), { shared: true });
+
+  let stmt = adb.createAsyncStatement("INSERT INTO test (name) VALUES (:name)");
+  stmt.params.name = "clockworker";
+  let result = await executeAsync(stmt);
+  info("Request complete");
+  stmt.finalize();
+  Assert.ok(Components.isSuccessCode(result));
+  info("Extracting data");
+  stmt = adb.createAsyncStatement("SELECT * FROM test");
+  let found = false;
+  await executeAsync(stmt, function (results) {
+    info("Data has been extracted");
+    for (
+      let row = results.getNextRow();
+      row != null;
+      row = results.getNextRow()
+    ) {
+      if (row.getResultByName("name") == "clockworker") {
+        found = true;
+        break;
+      }
+    }
+  });
+  Assert.ok(found);
+  stmt.finalize();
+  await asyncClose(adb);
+});
+
+add_task(async function test_clone_trivial_async() {
+  info("Open connection");
+  let db = Services.storage.openDatabase(getTestDB());
+  Assert.ok(db instanceof Ci.mozIStorageAsyncConnection);
+  info("AsyncClone connection");
+  let clone = await asyncClone(db, true);
+  Assert.ok(clone instanceof Ci.mozIStorageAsyncConnection);
+  Assert.ok(clone instanceof Ci.mozIStorageConnection);
+  info("Close connection");
+  await asyncClose(db);
+  info("Close clone");
+  await asyncClose(clone);
+});
+
+add_task(async function test_clone_no_optional_param_async() {
+  "use strict";
+  info("Testing async cloning");
+  let adb1 = await openAsyncDatabase(getTestDB(), null);
+  Assert.ok(adb1 instanceof Ci.mozIStorageAsyncConnection);
+  Assert.ok(adb1 instanceof Ci.mozIStorageConnection);
+
+  info("Cloning database");
+
+  let adb2 = await asyncClone(adb1);
+  info(
+    "Testing that the cloned db is a mozIStorageAsyncConnection " +
+      "and not a mozIStorageConnection"
+  );
+  Assert.ok(adb2 instanceof Ci.mozIStorageAsyncConnection);
+  Assert.ok(adb2 instanceof Ci.mozIStorageConnection);
+
+  info("Inserting data into source db");
+  let stmt = adb1.createAsyncStatement(
+    "INSERT INTO test (name) VALUES (:name)"
+  );
+
+  stmt.params.name = "yoric";
+  let result = await executeAsync(stmt);
+  info("Request complete");
+  stmt.finalize();
+  Assert.ok(Components.isSuccessCode(result));
+  info("Extracting data from clone db");
+  stmt = adb2.createAsyncStatement("SELECT * FROM test");
+  let found = false;
+  await executeAsync(stmt, function (results) {
+    info("Data has been extracted");
+    for (
+      let row = results.getNextRow();
+      row != null;
+      row = results.getNextRow()
+    ) {
+      if (row.getResultByName("name") == "yoric") {
+        found = true;
+        break;
+      }
+    }
+  });
+  Assert.ok(found);
+  stmt.finalize();
+  info("Closing databases");
+  await asyncClose(adb2);
+  info("First db closed");
+
+  await asyncClose(adb1);
+  info("Second db closed");
+});
+
+add_task(async function test_clone_readonly() {
+  let db1 = Services.storage.openUnsharedDatabase(getTestDB());
+  let db2 = db1.clone(true);
+  Assert.ok(db2.connectionReady);
+
+  // A write statement should fail here.
+  let stmt = db2.createStatement("INSERT INTO test (name) VALUES (:name)");
+  stmt.params.name = "reed";
+  expectError(Cr.NS_ERROR_FILE_READ_ONLY, () => stmt.execute());
+  stmt.finalize();
+
+  // And a read statement should succeed.
+  stmt = db2.createStatement("SELECT * FROM test");
+  Assert.ok(stmt.executeStep());
+  stmt.finalize();
+
+  db1.close();
+  db2.close();
+});
+
+add_task(async function test_clone_shared_readonly() {
+  let db1 = Services.storage.openDatabase(getTestDB());
+  let db2 = db1.clone(true);
+  Assert.ok(db2.connectionReady);
+
+  let stmt = db2.createStatement("INSERT INTO test (name) VALUES (:name)");
+  stmt.params.name = "parker";
+  // TODO currently SQLite does not actually work correctly here.  The behavior
+  //      we want is commented out, and the current behavior is being tested
+  //      for.  Our IDL comments will have to be updated when this starts to
+  //      work again.
+  stmt.execute();
+  // expectError(Components.results.NS_ERROR_FILE_READ_ONLY, () => stmt.execute());
+  stmt.finalize();
+
+  // And a read statement should succeed.
+  stmt = db2.createStatement("SELECT * FROM test");
+  Assert.ok(stmt.executeStep());
+  stmt.finalize();
+
+  db1.close();
+  db2.close();
+});
+
+add_task(async function test_close_clone_fails() {
+  let calls = ["openDatabase", "openUnsharedDatabase"];
+  calls.forEach(function (methodName) {
+    let db = Services.storage[methodName](getTestDB());
+    db.close();
+    expectError(Cr.NS_ERROR_NOT_INITIALIZED, () => db.clone());
+  });
+});
+
+add_task(async function test_clone_copies_functions() {
+  const FUNC_NAME = "test_func";
+  let calls = ["openDatabase", "openUnsharedDatabase"];
+  let functionMethods = ["createFunction"];
+  calls.forEach(function (methodName) {
+    [true, false].forEach(function (readOnly) {
+      functionMethods.forEach(function (functionMethod) {
+        let db1 = Services.storage[methodName](getTestDB());
+        // Create a function for db1.
+        db1[functionMethod](FUNC_NAME, 1, {
+          onFunctionCall: () => 0,
+          onStep: () => 0,
+          onFinal: () => 0,
+        });
+
+        // Clone it, and make sure the function exists still.
+        let db2 = db1.clone(readOnly);
+        // Note: this would fail if the function did not exist.
+        let stmt = db2.createStatement(
+          "SELECT " + FUNC_NAME + "(id) FROM test"
+        );
+        stmt.finalize();
+        db1.close();
+        db2.close();
+      });
+    });
+  });
+});
+
+add_task(async function test_clone_copies_overridden_functions() {
+  const FUNC_NAME = "lower";
+  function test_func() {
+    this.called = false;
+  }
+  test_func.prototype = {
+    onFunctionCall() {
+      this.called = true;
+    },
+    onStep() {
+      this.called = true;
+    },
+    onFinal: () => 0,
+  };
+
+  let calls = ["openDatabase", "openUnsharedDatabase"];
+  let functionMethods = ["createFunction"];
+  calls.forEach(function (methodName) {
+    [true, false].forEach(function (readOnly) {
+      functionMethods.forEach(function (functionMethod) {
+        let db1 = Services.storage[methodName](getTestDB());
+        // Create a function for db1.
+        let func = new test_func();
+        db1[functionMethod](FUNC_NAME, 1, func);
+        Assert.ok(!func.called);
+
+        // Clone it, and make sure the function gets called.
+        let db2 = db1.clone(readOnly);
+        let stmt = db2.createStatement(
+          "SELECT " + FUNC_NAME + "(id) FROM test"
+        );
+        stmt.executeStep();
+        Assert.ok(func.called);
+        stmt.finalize();
+        db1.close();
+        db2.close();
+      });
+    });
+  });
+});
+
+add_task(async function test_clone_copies_pragmas() {
+  const PRAGMAS = [
+    { name: "cache_size", value: 500, copied: true },
+    { name: "temp_store", value: 2, copied: true },
+    { name: "foreign_keys", value: 1, copied: true },
+    { name: "journal_size_limit", value: 524288, copied: true },
+    { name: "synchronous", value: 2, copied: true },
+    { name: "wal_autocheckpoint", value: 16, copied: true },
+    { name: "busy_timeout", value: 50, copied: true },
+    { name: "ignore_check_constraints", value: 1, copied: false },
+  ];
+
+  let db1 = Services.storage.openUnsharedDatabase(getTestDB());
+
+  // Sanity check initial values are different from enforced ones.
+  PRAGMAS.forEach(function (pragma) {
+    let stmt = db1.createStatement("PRAGMA " + pragma.name);
+    Assert.ok(stmt.executeStep());
+    Assert.notEqual(pragma.value, stmt.getInt32(0));
+    stmt.finalize();
+  });
+  // Execute pragmas.
+  PRAGMAS.forEach(function (pragma) {
+    db1.executeSimpleSQL("PRAGMA " + pragma.name + " = " + pragma.value);
+  });
+
+  let db2 = db1.clone();
+  Assert.ok(db2.connectionReady);
+
+  // Check cloned connection inherited pragma values.
+  PRAGMAS.forEach(function (pragma) {
+    let stmt = db2.createStatement("PRAGMA " + pragma.name);
+    Assert.ok(stmt.executeStep());
+    let validate = pragma.copied ? "equal" : "notEqual";
+    Assert[validate](pragma.value, stmt.getInt32(0));
+    stmt.finalize();
+  });
+
+  db1.close();
+  db2.close();
+});
+
+add_task(async function test_readonly_clone_copies_pragmas() {
+  const PRAGMAS = [
+    { name: "cache_size", value: 500, copied: true },
+    { name: "temp_store", value: 2, copied: true },
+    { name: "foreign_keys", value: 1, copied: false },
+    { name: "journal_size_limit", value: 524288, copied: false },
+    { name: "synchronous", value: 2, copied: false },
+    { name: "wal_autocheckpoint", value: 16, copied: false },
+    { name: "busy_timeout", value: 50, copied: false },
+    { name: "ignore_check_constraints", value: 1, copied: false },
+  ];
+
+  let db1 = Services.storage.openUnsharedDatabase(getTestDB());
+
+  // Sanity check initial values are different from enforced ones.
+  PRAGMAS.forEach(function (pragma) {
+    let stmt = db1.createStatement("PRAGMA " + pragma.name);
+    Assert.ok(stmt.executeStep());
+    Assert.notEqual(pragma.value, stmt.getInt32(0));
+    stmt.finalize();
+  });
+  // Execute pragmas.
+  PRAGMAS.forEach(function (pragma) {
+    db1.executeSimpleSQL("PRAGMA " + pragma.name + " = " + pragma.value);
+  });
+
+  let db2 = db1.clone(true);
+  Assert.ok(db2.connectionReady);
+
+  // Check cloned connection inherited pragma values.
+  PRAGMAS.forEach(function (pragma) {
+    let stmt = db2.createStatement("PRAGMA " + pragma.name);
+    Assert.ok(stmt.executeStep());
+    let validate = pragma.copied ? "equal" : "notEqual";
+    Assert[validate](pragma.value, stmt.getInt32(0));
+    stmt.finalize();
+  });
+
+  db1.close();
+  db2.close();
+});
+
+add_task(async function test_clone_attach_database() {
+  let db1 = Services.storage.openUnsharedDatabase(getTestDB());
+
+  let c = 0;
+  function attachDB(conn, name) {
+    let file = Services.dirsvc.get("ProfD", Ci.nsIFile);
+    file.append("test_storage_" + ++c + ".sqlite");
+    let db = Services.storage.openUnsharedDatabase(file);
+    conn.executeSimpleSQL(
+      `ATTACH DATABASE '${db.databaseFile.path}' AS ${name}`
+    );
+    db.executeSimpleSQL(`CREATE TABLE test_${name}(name TEXT);`);
+    db.close();
+  }
+  attachDB(db1, "attached_1");
+  attachDB(db1, "attached_2");
+  db1.executeSimpleSQL(`
+    CREATE TEMP TRIGGER test_temp_afterinsert_trigger
+    AFTER DELETE ON test_attached_1 FOR EACH ROW
+    BEGIN
+      INSERT INTO test(name) VALUES(OLD.name);
+    END`);
+
+  // These should not throw.
+  let stmt = db1.createStatement("SELECT * FROM attached_1.sqlite_master");
+  stmt.finalize();
+  stmt = db1.createStatement("SELECT * FROM attached_2.sqlite_master");
+  stmt.finalize();
+  db1.executeSimpleSQL("INSERT INTO test_attached_1(name) VALUES('asuth')");
+  db1.executeSimpleSQL("DELETE FROM test_attached_1");
+  Assert.ok(fetchAllNames(db1).includes("asuth"));
+
+  // R/W clone.
+  let db2 = db1.clone();
+  Assert.ok(db2.connectionReady);
+
+  // These should not throw.
+  stmt = db2.createStatement("SELECT * FROM attached_1.sqlite_master");
+  stmt.finalize();
+  stmt = db2.createStatement("SELECT * FROM attached_2.sqlite_master");
+  stmt.finalize();
+  db2.executeSimpleSQL("INSERT INTO test_attached_1(name) VALUES('past')");
+  db2.executeSimpleSQL("DELETE FROM test_attached_1");
+  let newNames = fetchAllNames(db2);
+  Assert.ok(newNames.includes("past"));
+  Assert.deepEqual(fetchAllNames(db1), newNames);
+
+  // R/O clone.
+  let db3 = db1.clone(true);
+  Assert.ok(db3.connectionReady);
+
+  // These should not throw.
+  stmt = db3.createStatement("SELECT * FROM attached_1.sqlite_master");
+  stmt.finalize();
+  stmt = db3.createStatement("SELECT * FROM attached_2.sqlite_master");
+  stmt.finalize();
+
+  db1.close();
+  db2.close();
+  db3.close();
+});
+
+add_task(async function test_async_clone_with_temp_trigger_and_table() {
+  info("Open connection");
+  let db = Services.storage.openDatabase(getTestDB());
+  Assert.ok(db instanceof Ci.mozIStorageAsyncConnection);
+
+  info("Set up tables on original connection");
+  let createQueries = [
+    `CREATE TEMP TABLE test_temp(name TEXT)`,
+    `CREATE INDEX test_temp_idx ON test_temp(name)`,
+    `CREATE TEMP TRIGGER test_temp_afterdelete_trigger
+     AFTER DELETE ON test_temp FOR EACH ROW
+     BEGIN
+       INSERT INTO test(name) VALUES(OLD.name);
+     END`,
+  ];
+  for (let query of createQueries) {
+    let stmt = db.createAsyncStatement(query);
+    await executeAsync(stmt);
+    stmt.finalize();
+  }
+
+  info("Create read-write clone with temp tables");
+  let readWriteClone = await asyncClone(db, false);
+  Assert.ok(readWriteClone instanceof Ci.mozIStorageAsyncConnection);
+
+  info("Insert into temp table on read-write clone");
+  let insertStmt = readWriteClone.createAsyncStatement(`
+    INSERT INTO test_temp(name) VALUES('mak'), ('standard8'), ('markh')`);
+  await executeAsync(insertStmt);
+  insertStmt.finalize();
+
+  info("Fire temp trigger on read-write clone");
+  let deleteStmt = readWriteClone.createAsyncStatement(`
+    DELETE FROM test_temp`);
+  await executeAsync(deleteStmt);
+  deleteStmt.finalize();
+
+  info("Read from original connection");
+  let names = fetchAllNames(db);
+  Assert.ok(names.includes("mak"));
+  Assert.ok(names.includes("standard8"));
+  Assert.ok(names.includes("markh"));
+
+  info("Create read-only clone");
+  let readOnlyClone = await asyncClone(db, true);
+  Assert.ok(readOnlyClone instanceof Ci.mozIStorageAsyncConnection);
+
+  info("Read-only clone shouldn't have temp entities");
+  let badStmt = readOnlyClone.createAsyncStatement(`SELECT 1 FROM test_temp`);
+  await Assert.rejects(executeAsync(badStmt), Ci.mozIStorageError);
+  badStmt.finalize();
+
+  info("Clean up");
+  for (let conn of [db, readWriteClone, readOnlyClone]) {
+    await asyncClose(conn);
+  }
+});
+
+add_task(async function test_sync_clone_in_transaction() {
+  info("Open connection");
+  let db = Services.storage.openDatabase(getTestDB());
+  Assert.ok(db instanceof Ci.mozIStorageAsyncConnection);
+
+  info("Begin transaction on main connection");
+  db.beginTransaction();
+
+  info("Create temp table and trigger in transaction");
+  let createQueries = [
+    `CREATE TEMP TABLE test_temp(name TEXT)`,
+    `CREATE TEMP TRIGGER test_temp_afterdelete_trigger
+     AFTER DELETE ON test_temp FOR EACH ROW
+     BEGIN
+       INSERT INTO test(name) VALUES(OLD.name);
+     END`,
+  ];
+  for (let query of createQueries) {
+    db.executeSimpleSQL(query);
+  }
+
+  info("Clone main connection while transaction is in progress");
+  let clone = db.clone(/* aReadOnly */ false);
+
+  // Dropping the table also drops `test_temp_afterdelete_trigger`.
+  info("Drop temp table on main connection");
+  db.executeSimpleSQL(`DROP TABLE test_temp`);
+
+  info("Commit transaction");
+  db.commitTransaction();
+
+  info("Clone connection should still have temp entities");
+  let readTempStmt = clone.createStatement(`SELECT 1 FROM test_temp`);
+  readTempStmt.execute();
+  readTempStmt.finalize();
+
+  info("Clean up");
+
+  db.close();
+  clone.close();
+});
+
+add_task(async function test_sync_clone_with_function() {
+  info("Open connection");
+  let db = Services.storage.openDatabase(getTestDB());
+  Assert.ok(db instanceof Ci.mozIStorageAsyncConnection);
+
+  info("Create SQL function");
+  function storeLastInsertedNameFunc() {
+    this.name = null;
+  }
+  storeLastInsertedNameFunc.prototype = {
+    onFunctionCall(args) {
+      this.name = args.getUTF8String(0);
+    },
+  };
+  let func = new storeLastInsertedNameFunc();
+  db.createFunction("store_last_inserted_name", 1, func);
+
+  info("Create temp trigger on main connection");
+  db.executeSimpleSQL(`
+    CREATE TEMP TRIGGER test_afterinsert_trigger
+    AFTER INSERT ON test FOR EACH ROW
+    BEGIN
+      SELECT store_last_inserted_name(NEW.name);
+    END`);
+
+  info("Clone main connection");
+  let clone = db.clone(/* aReadOnly */ false);
+
+  info("Write to clone");
+  clone.executeSimpleSQL(`INSERT INTO test(name) VALUES('kit')`);
+
+  Assert.equal(func.name, "kit");
+
+  info("Clean up");
+  db.close();
+  clone.close();
+});
+
+add_task(async function test_defaultTransactionType() {
+  info("Open connection");
+  let db = Services.storage.openDatabase(getTestDB());
+  Assert.ok(db instanceof Ci.mozIStorageAsyncConnection);
+
+  info("Verify default transaction type");
+  Assert.equal(
+    db.defaultTransactionType,
+    Ci.mozIStorageConnection.TRANSACTION_DEFERRED
+  );
+
+  info("Test other transaction types");
+  for (let type of [
+    Ci.mozIStorageConnection.TRANSACTION_IMMEDIATE,
+    Ci.mozIStorageConnection.TRANSACTION_EXCLUSIVE,
+  ]) {
+    db.defaultTransactionType = type;
+    Assert.equal(db.defaultTransactionType, type);
+  }
+
+  info("Should reject unknown transaction types");
+  Assert.throws(
+    () =>
+      (db.defaultTransactionType =
+        Ci.mozIStorageConnection.TRANSACTION_DEFAULT),
+    /NS_ERROR_ILLEGAL_VALUE/
+  );
+
+  db.defaultTransactionType = Ci.mozIStorageConnection.TRANSACTION_IMMEDIATE;
+
+  info("Clone should inherit default transaction type");
+  let clone = await asyncClone(db, true);
+  Assert.ok(clone instanceof Ci.mozIStorageAsyncConnection);
+  Assert.equal(
+    clone.defaultTransactionType,
+    Ci.mozIStorageConnection.TRANSACTION_IMMEDIATE
+  );
+
+  info("Begin immediate transaction on main connection");
+  db.beginTransaction();
+
+  info("Queue immediate transaction on clone");
+  let stmts = [
+    clone.createAsyncStatement(`BEGIN IMMEDIATE TRANSACTION`),
+    clone.createAsyncStatement(`DELETE FROM test WHERE name = 'new'`),
+    clone.createAsyncStatement(`COMMIT`),
+  ];
+  let promiseStmtsRan = stmts.map(stmt => executeAsync(stmt));
+
+  info("Commit immediate transaction on main connection");
+  db.executeSimpleSQL(`INSERT INTO test(name) VALUES('new')`);
+  db.commitTransaction();
+
+  info("Wait for transaction to succeed on clone");
+  await Promise.all(promiseStmtsRan);
+
+  info("Clean up");
+  for (let stmt of stmts) {
+    stmt.finalize();
+  }
+  await asyncClose(clone);
+  await asyncClose(db);
+});
+
+add_task(async function test_variableLimit() {
+  info("Open connection");
+  let db = Services.storage.openDatabase(getTestDB());
+  Assert.equal(db.variableLimit, 32766, "Should return default limit");
+  await asyncClose(db);
+});
+
+add_task(async function test_getInterface() {
+  let db = getOpenedDatabase();
+  let target = db
+    .QueryInterface(Ci.nsIInterfaceRequestor)
+    .getInterface(Ci.nsIEventTarget);
+  // Just check that target is non-null.  Other tests will ensure that it has
+  // the correct value.
+  Assert.ok(target != null);
+
+  await asyncClose(db);
+  gDBConn = null;
+});
diff --git a/storage/test/unit/test_storage_ext.js b/storage/test/unit/test_storage_ext.js
new file mode 100644
index 0000000000..748ac86750
--- /dev/null
+++ b/storage/test/unit/test_storage_ext.js
@@ -0,0 +1,84 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file tests basics of loading SQLite extension.
+
+const VALID_EXTENSION_NAME = "fts5";
+
+add_setup(async function () {
+  cleanup();
+});
+
+add_task(async function test_valid_call() {
+  info("Testing valid call");
+  let conn = getOpenedUnsharedDatabase();
+
+  await new Promise((resolve, reject) => {
+    conn.loadExtension(VALID_EXTENSION_NAME, status => {
+      if (Components.isSuccessCode(status)) {
+        resolve();
+      } else {
+        reject(status);
+      }
+    });
+  });
+
+  cleanup();
+});
+
+add_task(async function test_invalid_calls() {
+  info("Testing invalid calls");
+  let conn = getOpenedUnsharedDatabase();
+
+  await Assert.rejects(
+    new Promise((resolve, reject) => {
+      conn.loadExtension("unknown", status => {
+        if (Components.isSuccessCode(status)) {
+          resolve();
+        } else {
+          reject(status);
+        }
+      });
+    }),
+    /NS_ERROR_ILLEGAL_VALUE/,
+    "Should fail loading unknown extension"
+  );
+
+  cleanup();
+
+  await Assert.rejects(
+    new Promise((resolve, reject) => {
+      conn.loadExtension(VALID_EXTENSION_NAME, status => {
+        if (Components.isSuccessCode(status)) {
+          resolve();
+        } else {
+          reject(status);
+        }
+      });
+    }),
+    /NS_ERROR_NOT_INITIALIZED/,
+    "Should fail loading extension on a closed connection"
+  );
+});
+
+add_task(async function test_more_invalid_calls() {
+  let conn = getOpenedUnsharedDatabase();
+  let promiseClosed = asyncClose(conn);
+
+  await Assert.rejects(
+    new Promise((resolve, reject) => {
+      conn.loadExtension(VALID_EXTENSION_NAME, status => {
+        if (Components.isSuccessCode(status)) {
+          resolve();
+        } else {
+          reject(status);
+        }
+      });
+    }),
+    /NS_ERROR_NOT_INITIALIZED/,
+    "Should fail loading extension on a closing connection"
+  );
+
+  await promiseClosed;
+});
diff --git a/storage/test/unit/test_storage_ext_fts3.js b/storage/test/unit/test_storage_ext_fts3.js
new file mode 100644
index 0000000000..bcc9491a93
--- /dev/null
+++ b/storage/test/unit/test_storage_ext_fts3.js
@@ -0,0 +1,91 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file tests support for the fts3 (full-text index) module.
+
+// Example statements in these tests are taken from the Full Text Index page
+// on the SQLite wiki: http://www.sqlite.org/cvstrac/wiki?p=FullTextIndex
+
+function test_table_creation() {
+  var msc = getOpenedUnsharedDatabase();
+
+  msc.executeSimpleSQL(
+    "CREATE VIRTUAL TABLE recipe USING fts3(name, ingredients)"
+  );
+
+  Assert.ok(msc.tableExists("recipe"));
+}
+
+function test_insertion() {
+  var msc = getOpenedUnsharedDatabase();
+
+  msc.executeSimpleSQL(
+    "INSERT INTO recipe (name, ingredients) VALUES " +
+      "('broccoli stew', 'broccoli peppers cheese tomatoes')"
+  );
+  msc.executeSimpleSQL(
+    "INSERT INTO recipe (name, ingredients) VALUES " +
+      "('pumpkin stew', 'pumpkin onions garlic celery')"
+  );
+  msc.executeSimpleSQL(
+    "INSERT INTO recipe (name, ingredients) VALUES " +
+      "('broccoli pie', 'broccoli cheese onions flour')"
+  );
+  msc.executeSimpleSQL(
+    "INSERT INTO recipe (name, ingredients) VALUES " +
+      "('pumpkin pie', 'pumpkin sugar flour butter')"
+  );
+
+  var stmt = msc.createStatement("SELECT COUNT(*) FROM recipe");
+  stmt.executeStep();
+
+  Assert.equal(stmt.getInt32(0), 4);
+
+  stmt.reset();
+  stmt.finalize();
+}
+
+function test_selection() {
+  var msc = getOpenedUnsharedDatabase();
+
+  var stmt = msc.createStatement(
+    "SELECT rowid, name, ingredients FROM recipe WHERE name MATCH 'pie'"
+  );
+
+  Assert.ok(stmt.executeStep());
+  Assert.equal(stmt.getInt32(0), 3);
+  Assert.equal(stmt.getString(1), "broccoli pie");
+  Assert.equal(stmt.getString(2), "broccoli cheese onions flour");
+
+  Assert.ok(stmt.executeStep());
+  Assert.equal(stmt.getInt32(0), 4);
+  Assert.equal(stmt.getString(1), "pumpkin pie");
+  Assert.equal(stmt.getString(2), "pumpkin sugar flour butter");
+
+  Assert.ok(!stmt.executeStep());
+
+  stmt.reset();
+  stmt.finalize();
+}
+
+var tests = [test_table_creation, test_insertion, test_selection];
+
+function run_test() {
+  // It's extra important to start from scratch, since these tests won't work
+  // with an existing shared cache connection, so we do it even though the last
+  // test probably did it already.
+  cleanup();
+
+  try {
+    for (var i = 0; i < tests.length; i++) {
+      tests[i]();
+    }
+  } finally {
+    // It's extra important to clean up afterwards, since later tests that use
+    // a shared cache connection will not be able to read the database we create,
+    // so we do this in a finally block to ensure it happens even if some of our
+    // tests fail.
+    cleanup();
+  }
+}
diff --git a/storage/test/unit/test_storage_ext_fts5.js b/storage/test/unit/test_storage_ext_fts5.js
new file mode 100644
index 0000000000..7adf4e8b83
--- /dev/null
+++ b/storage/test/unit/test_storage_ext_fts5.js
@@ -0,0 +1,122 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file tests support for the fts5 extension.
+
+// Some example statements in this tests are taken from the SQLite FTS5
+// documentation page: https://sqlite.org/fts5.html
+
+add_setup(async function () {
+  cleanup();
+});
+
+add_task(async function test_synchronous() {
+  info("Testing synchronous connection");
+  let conn = getOpenedUnsharedDatabase();
+  Assert.throws(
+    () =>
+      conn.executeSimpleSQL(
+        "CREATE VIRTUAL TABLE email USING fts5(sender, title, body);"
+      ),
+    /NS_ERROR_FAILURE/,
+    "Should not be able to use FTS5 without loading the extension"
+  );
+
+  await loadFTS5Extension(conn);
+
+  conn.executeSimpleSQL(
+    "CREATE VIRTUAL TABLE email USING fts5(sender, title, body, tokenize='trigram');"
+  );
+
+  conn.executeSimpleSQL(
+    `INSERT INTO email(sender, title, body) VALUES
+    ('Mark', 'Fox', 'The quick brown fox jumps over the lazy dog.'),
+    ('Marco', 'Cat', 'The quick brown cat jumps over the lazy dog.'),
+    ('James', 'Hamster', 'The quick brown hamster jumps over the lazy dog.')`
+  );
+
+  var stmt = conn.createStatement(
+    `SELECT sender, title, highlight(email, 2, '<', '>')
+     FROM email
+     WHERE email MATCH 'ham'
+     ORDER BY bm25(email)`
+  );
+  Assert.ok(stmt.executeStep());
+  Assert.equal(stmt.getString(0), "James");
+  Assert.equal(stmt.getString(1), "Hamster");
+  Assert.equal(
+    stmt.getString(2),
+    "The quick brown <ham>ster jumps over the lazy dog."
+  );
+  stmt.reset();
+  stmt.finalize();
+
+  cleanup();
+});
+
+add_task(async function test_asynchronous() {
+  info("Testing asynchronous connection");
+  let conn = await openAsyncDatabase(getTestDB());
+
+  await Assert.rejects(
+    executeSimpleSQLAsync(
+      conn,
+      "CREATE VIRTUAL TABLE email USING fts5(sender, title, body);"
+    ),
+    err => err.message.startsWith("no such module"),
+    "Should not be able to use FTS5 without loading the extension"
+  );
+
+  await loadFTS5Extension(conn);
+
+  await executeSimpleSQLAsync(
+    conn,
+    "CREATE VIRTUAL TABLE email USING fts5(sender, title, body);"
+  );
+
+  await asyncClose(conn);
+  await IOUtils.remove(getTestDB().path, { ignoreAbsent: true });
+});
+
+add_task(async function test_clone() {
+  info("Testing cloning synchronous connection loads extensions in clone");
+  let conn1 = getOpenedUnsharedDatabase();
+  await loadFTS5Extension(conn1);
+
+  let conn2 = conn1.clone(false);
+  conn2.executeSimpleSQL(
+    "CREATE VIRTUAL TABLE email USING fts5(sender, title, body);"
+  );
+
+  conn2.close();
+  cleanup();
+});
+
+add_task(async function test_asyncClone() {
+  info("Testing asynchronously cloning connection loads extensions in clone");
+  let conn1 = getOpenedUnsharedDatabase();
+  await loadFTS5Extension(conn1);
+
+  let conn2 = await asyncClone(conn1, false);
+  await executeSimpleSQLAsync(
+    conn2,
+    "CREATE VIRTUAL TABLE email USING fts5(sender, title, body);"
+  );
+
+  await asyncClose(conn2);
+  await asyncClose(conn1);
+  await IOUtils.remove(getTestDB().path, { ignoreAbsent: true });
+});
+
+async function loadFTS5Extension(conn) {
+  await new Promise((resolve, reject) => {
+    conn.loadExtension("fts5", status => {
+      if (Components.isSuccessCode(status)) {
+        resolve();
+      } else {
+        reject(status);
+      }
+    });
+  });
+}
diff --git a/storage/test/unit/test_storage_function.js b/storage/test/unit/test_storage_function.js
new file mode 100644
index 0000000000..1b11aa4a52
--- /dev/null
+++ b/storage/test/unit/test_storage_function.js
@@ -0,0 +1,92 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file tests the custom functions
+
+var testNums = [1, 2, 3, 4];
+
+function setup() {
+  getOpenedDatabase().createTable("function_tests", "id INTEGER PRIMARY KEY");
+
+  var stmt = createStatement("INSERT INTO function_tests (id) VALUES(?1)");
+  for (let i = 0; i < testNums.length; ++i) {
+    stmt.bindByIndex(0, testNums[i]);
+    stmt.execute();
+  }
+  stmt.reset();
+  stmt.finalize();
+}
+
+var testSquareFunction = {
+  calls: 0,
+
+  onFunctionCall(val) {
+    ++this.calls;
+    return val.getInt32(0) * val.getInt32(0);
+  },
+};
+
+function test_function_registration() {
+  var msc = getOpenedDatabase();
+  msc.createFunction("test_square", 1, testSquareFunction);
+}
+
+function test_function_no_double_registration() {
+  var msc = getOpenedDatabase();
+  try {
+    msc.createFunction("test_square", 2, testSquareFunction);
+    do_throw("We shouldn't get here!");
+  } catch (e) {
+    Assert.equal(Cr.NS_ERROR_FAILURE, e.result);
+  }
+}
+
+function test_function_removal() {
+  var msc = getOpenedDatabase();
+  msc.removeFunction("test_square");
+  // Should be Ok now
+  msc.createFunction("test_square", 1, testSquareFunction);
+}
+
+function test_function_aliases() {
+  var msc = getOpenedDatabase();
+  msc.createFunction("test_square2", 1, testSquareFunction);
+}
+
+function test_function_call() {
+  var stmt = createStatement("SELECT test_square(id) FROM function_tests");
+  while (stmt.executeStep()) {
+    // Do nothing.
+  }
+  Assert.equal(testNums.length, testSquareFunction.calls);
+  testSquareFunction.calls = 0;
+  stmt.finalize();
+}
+
+function test_function_result() {
+  var stmt = createStatement("SELECT test_square(42) FROM function_tests");
+  stmt.executeStep();
+  Assert.equal(42 * 42, stmt.getInt32(0));
+  testSquareFunction.calls = 0;
+  stmt.finalize();
+}
+
+var tests = [
+  test_function_registration,
+  test_function_no_double_registration,
+  test_function_removal,
+  test_function_aliases,
+  test_function_call,
+  test_function_result,
+];
+
+function run_test() {
+  setup();
+
+  for (var i = 0; i < tests.length; i++) {
+    tests[i]();
+  }
+
+  cleanup();
+}
diff --git a/storage/test/unit/test_storage_progresshandler.js b/storage/test/unit/test_storage_progresshandler.js
new file mode 100644
index 0000000000..e2e01eb2ff
--- /dev/null
+++ b/storage/test/unit/test_storage_progresshandler.js
@@ -0,0 +1,112 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file tests the custom progress handlers
+
+function setup() {
+  var msc = getOpenedDatabase();
+  msc.createTable("handler_tests", "id INTEGER PRIMARY KEY, num INTEGER");
+  msc.beginTransaction();
+
+  var stmt = createStatement(
+    "INSERT INTO handler_tests (id, num) VALUES(?1, ?2)"
+  );
+  for (let i = 0; i < 100; ++i) {
+    stmt.bindByIndex(0, i);
+    stmt.bindByIndex(1, Math.floor(Math.random() * 1000));
+    stmt.execute();
+  }
+  stmt.reset();
+  msc.commitTransaction();
+  stmt.finalize();
+}
+
+var testProgressHandler = {
+  calls: 0,
+  abort: false,
+
+  onProgress(comm) {
+    ++this.calls;
+    return this.abort;
+  },
+};
+
+function test_handler_registration() {
+  var msc = getOpenedDatabase();
+  msc.setProgressHandler(10, testProgressHandler);
+}
+
+function test_handler_return() {
+  var msc = getOpenedDatabase();
+  var oldH = msc.setProgressHandler(5, testProgressHandler);
+  Assert.ok(oldH instanceof Ci.mozIStorageProgressHandler);
+}
+
+function test_handler_removal() {
+  var msc = getOpenedDatabase();
+  msc.removeProgressHandler();
+  var oldH = msc.removeProgressHandler();
+  Assert.equal(oldH, null);
+}
+
+function test_handler_call() {
+  var msc = getOpenedDatabase();
+  msc.setProgressHandler(50, testProgressHandler);
+  // Some long-executing request
+  var stmt = createStatement(
+    "SELECT SUM(t1.num * t2.num) FROM handler_tests AS t1, handler_tests AS t2"
+  );
+  while (stmt.executeStep()) {
+    // Do nothing.
+  }
+  Assert.ok(testProgressHandler.calls > 0);
+  stmt.finalize();
+}
+
+function test_handler_abort() {
+  var msc = getOpenedDatabase();
+  testProgressHandler.abort = true;
+  msc.setProgressHandler(50, testProgressHandler);
+  // Some long-executing request
+  var stmt = createStatement(
+    "SELECT SUM(t1.num * t2.num) FROM handler_tests AS t1, handler_tests AS t2"
+  );
+
+  const SQLITE_INTERRUPT = 9;
+  try {
+    while (stmt.executeStep()) {
+      // Do nothing.
+    }
+    do_throw("We shouldn't get here!");
+  } catch (e) {
+    Assert.equal(Cr.NS_ERROR_ABORT, e.result);
+    Assert.equal(SQLITE_INTERRUPT, msc.lastError);
+  }
+  try {
+    stmt.finalize();
+    do_throw("We shouldn't get here!");
+  } catch (e) {
+    // finalize should return the error code since we encountered an error
+    Assert.equal(Cr.NS_ERROR_ABORT, e.result);
+    Assert.equal(SQLITE_INTERRUPT, msc.lastError);
+  }
+}
+
+var tests = [
+  test_handler_registration,
+  test_handler_return,
+  test_handler_removal,
+  test_handler_call,
+  test_handler_abort,
+];
+
+function run_test() {
+  setup();
+
+  for (var i = 0; i < tests.length; i++) {
+    tests[i]();
+  }
+
+  cleanup();
+}
diff --git a/storage/test/unit/test_storage_service.js b/storage/test/unit/test_storage_service.js
new file mode 100644
index 0000000000..62a933cfbf
--- /dev/null
+++ b/storage/test/unit/test_storage_service.js
@@ -0,0 +1,267 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file tests the functions of mozIStorageService except for
+// openSpecialDatabase, which is tested by test_storage_service_special.js and
+// openUnsharedDatabase, which is tested by test_storage_service_unshared.js.
+
+function test_openDatabase_null_file() {
+  try {
+    Services.storage.openDatabase(null);
+    do_throw("We should not get here!");
+  } catch (e) {
+    print(e);
+    print("e.result is " + e.result);
+    Assert.equal(Cr.NS_ERROR_INVALID_ARG, e.result);
+  }
+}
+
+function test_openDatabase_file_DNE() {
+  // the file should be created after calling
+
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(OPEN_HISTOGRAM);
+
+  var db = getTestDB();
+  Assert.ok(!db.exists());
+  Services.storage.openDatabase(db);
+  Assert.ok(db.exists());
+
+  TelemetryTestUtils.assertKeyedHistogramValue(
+    histogram,
+    db.leafName,
+    TELEMETRY_VALUES.success,
+    1
+  );
+}
+
+function test_openDatabase_file_exists() {
+  // it should already exist from our last test
+
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(OPEN_HISTOGRAM);
+
+  var db = getTestDB();
+  Assert.ok(db.exists());
+  Services.storage.openDatabase(db);
+  Assert.ok(db.exists());
+
+  TelemetryTestUtils.assertKeyedHistogramValue(
+    histogram,
+    db.leafName,
+    TELEMETRY_VALUES.success,
+    1
+  );
+}
+
+function test_corrupt_db_throws_with_openDatabase() {
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(OPEN_HISTOGRAM);
+
+  let db = getCorruptDB();
+
+  try {
+    getDatabase(db);
+    do_throw("should not be here");
+  } catch (e) {
+    Assert.equal(Cr.NS_ERROR_FILE_CORRUPTED, e.result);
+  }
+
+  TelemetryTestUtils.assertKeyedHistogramValue(
+    histogram,
+    db.leafName,
+    TELEMETRY_VALUES.corrupt,
+    1
+  );
+}
+
+function test_fake_db_throws_with_openDatabase() {
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(OPEN_HISTOGRAM);
+
+  let db = getFakeDB();
+
+  try {
+    getDatabase(db);
+    do_throw("should not be here");
+  } catch (e) {
+    Assert.equal(Cr.NS_ERROR_FILE_CORRUPTED, e.result);
+  }
+
+  TelemetryTestUtils.assertKeyedHistogramValue(
+    histogram,
+    db.leafName,
+    TELEMETRY_VALUES.corrupt,
+    1
+  );
+}
+
+function test_openDatabase_directory() {
+  let dir = getTestDB().parent;
+  dir.append("test_storage_temp");
+  if (dir.exists()) {
+    dir.remove(true);
+  }
+  dir.create(Ci.nsIFile.DIRECTORY_TYPE, 0o755);
+  Assert.ok(dir.exists());
+
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(OPEN_HISTOGRAM);
+
+  try {
+    getDatabase(dir);
+    do_throw("should not be here");
+  } catch (e) {
+    Assert.equal(Cr.NS_ERROR_FILE_ACCESS_DENIED, e.result);
+  }
+
+  TelemetryTestUtils.assertKeyedHistogramValue(
+    histogram,
+    dir.leafName,
+    TELEMETRY_VALUES.access,
+    1
+  );
+
+  dir.remove(true);
+}
+
+function test_read_gooddb() {
+  let file = do_get_file("goodDB.sqlite");
+  let db = getDatabase(file);
+
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(QUERY_HISTOGRAM);
+
+  db.executeSimpleSQL("SELECT * FROM Foo;");
+
+  TelemetryTestUtils.assertKeyedHistogramValue(
+    histogram,
+    file.leafName,
+    TELEMETRY_VALUES.success,
+    1
+  );
+
+  histogram.clear();
+
+  let stmt = db.createStatement("SELECT id from Foo");
+
+  while (true) {
+    if (!stmt.executeStep()) {
+      break;
+    }
+  }
+
+  stmt.finalize();
+
+  // A single statement should count as a single access.
+  TelemetryTestUtils.assertKeyedHistogramValue(
+    histogram,
+    file.leafName,
+    TELEMETRY_VALUES.success,
+    1
+  );
+
+  histogram.clear();
+
+  Assert.throws(
+    () => db.executeSimpleSQL("INSERT INTO Foo (rowid) VALUES ('test');"),
+    /NS_ERROR_FAILURE/,
+    "Executing sql should fail."
+  );
+  TelemetryTestUtils.assertKeyedHistogramValue(
+    histogram,
+    file.leafName,
+    TELEMETRY_VALUES.misuse,
+    1
+  );
+}
+
+function test_read_baddb() {
+  let file = do_get_file("baddataDB.sqlite");
+  let db = getDatabase(file);
+
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(QUERY_HISTOGRAM);
+
+  Assert.throws(
+    () => db.executeSimpleSQL("SELECT * FROM Foo"),
+    /NS_ERROR_FILE_CORRUPTED/,
+    "Executing sql should fail."
+  );
+
+  TelemetryTestUtils.assertKeyedHistogramValue(
+    histogram,
+    file.leafName,
+    TELEMETRY_VALUES.corrupt,
+    1
+  );
+
+  histogram.clear();
+
+  let stmt = db.createStatement("SELECT * FROM Foo");
+  Assert.throws(
+    () => stmt.executeStep(),
+    /NS_ERROR_FILE_CORRUPTED/,
+    "Executing a statement should fail."
+  );
+
+  TelemetryTestUtils.assertKeyedHistogramValue(
+    histogram,
+    file.leafName,
+    TELEMETRY_VALUES.corrupt,
+    1
+  );
+}
+
+function test_busy_telemetry() {
+  // Thunderbird doesn't have one or more of the probes used in this test.
+  // Ensure the data is collected anyway.
+  Services.prefs.setBoolPref(
+    "toolkit.telemetry.testing.overrideProductsCheck",
+    true
+  );
+
+  let file = do_get_file("goodDB.sqlite");
+  let conn1 = Services.storage.openUnsharedDatabase(file);
+  let conn2 = Services.storage.openUnsharedDatabase(file);
+
+  conn1.beginTransaction();
+  conn1.executeSimpleSQL("CREATE TABLE test (id INTEGER PRIMARY KEY)");
+
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(QUERY_HISTOGRAM);
+  Assert.throws(
+    () =>
+      conn2.executeSimpleSQL("CREATE TABLE test_busy (id INTEGER PRIMARY KEY)"),
+    /NS_ERROR_STORAGE_BUSY/,
+    "Nested transaction on second connection should fail"
+  );
+  TelemetryTestUtils.assertKeyedHistogramValue(
+    histogram,
+    file.leafName,
+    TELEMETRY_VALUES.busy,
+    1
+  );
+
+  conn1.rollbackTransaction();
+}
+
+var tests = [
+  test_openDatabase_null_file,
+  test_openDatabase_file_DNE,
+  test_openDatabase_file_exists,
+  test_corrupt_db_throws_with_openDatabase,
+  test_fake_db_throws_with_openDatabase,
+  test_openDatabase_directory,
+  test_read_gooddb,
+  test_read_baddb,
+  test_busy_telemetry,
+];
+
+function run_test() {
+  // Thunderbird doesn't have one or more of the probes used in this test.
+  // Ensure the data is collected anyway.
+  Services.prefs.setBoolPref(
+    "toolkit.telemetry.testing.overrideProductsCheck",
+    true
+  );
+
+  for (var i = 0; i < tests.length; i++) {
+    tests[i]();
+  }
+
+  cleanup();
+}
diff --git a/storage/test/unit/test_storage_service_special.js b/storage/test/unit/test_storage_service_special.js
new file mode 100644
index 0000000000..50cde042af
--- /dev/null
+++ b/storage/test/unit/test_storage_service_special.js
@@ -0,0 +1,48 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file tests the openSpecialDatabase function of mozIStorageService.
+
+add_task(async function test_invalid_storage_key() {
+  try {
+    Services.storage.openSpecialDatabase("abcd");
+    do_throw("We should not get here!");
+  } catch (e) {
+    print(e);
+    print("e.result is " + e.result);
+    Assert.equal(Cr.NS_ERROR_INVALID_ARG, e.result);
+  }
+});
+
+add_task(async function test_memdb_close_clone_fails() {
+  for (const name of [null, "foo"]) {
+    const db = Services.storage.openSpecialDatabase("memory", name);
+    db.close();
+    expectError(Cr.NS_ERROR_NOT_INITIALIZED, () => db.clone());
+  }
+});
+
+add_task(async function test_memdb_no_file_on_disk() {
+  for (const name of [null, "foo"]) {
+    const db = Services.storage.openSpecialDatabase("memory", name);
+    db.close();
+    for (const dirKey of ["CurWorkD", "ProfD"]) {
+      const dir = Services.dirsvc.get(dirKey, Ci.nsIFile);
+      const file = dir.clone();
+      file.append(!name ? ":memory:" : "file:foo?mode=memory&cache=shared");
+      Assert.ok(!file.exists());
+    }
+  }
+});
+
+add_task(async function test_memdb_sharing() {
+  for (const name of [null, "foo"]) {
+    const db = Services.storage.openSpecialDatabase("memory", name);
+    db.executeSimpleSQL("CREATE TABLE test(name TEXT)");
+    const db2 = Services.storage.openSpecialDatabase("memory", name);
+    Assert.ok(!!name == db2.tableExists("test"));
+    db.close();
+    db2.close();
+  }
+});
diff --git a/storage/test/unit/test_storage_service_unshared.js b/storage/test/unit/test_storage_service_unshared.js
new file mode 100644
index 0000000000..da1865dfa6
--- /dev/null
+++ b/storage/test/unit/test_storage_service_unshared.js
@@ -0,0 +1,46 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file tests the openUnsharedDatabase function of mozIStorageService.
+
+function test_openUnsharedDatabase_null_file() {
+  try {
+    Services.storage.openUnsharedDatabase(null);
+    do_throw("We should not get here!");
+  } catch (e) {
+    print(e);
+    print("e.result is " + e.result);
+    Assert.equal(Cr.NS_ERROR_INVALID_ARG, e.result);
+  }
+}
+
+function test_openUnsharedDatabase_file_DNE() {
+  // the file should be created after calling
+  var db = getTestDB();
+  Assert.ok(!db.exists());
+  Services.storage.openUnsharedDatabase(db);
+  Assert.ok(db.exists());
+}
+
+function test_openUnsharedDatabase_file_exists() {
+  // it should already exist from our last test
+  var db = getTestDB();
+  Assert.ok(db.exists());
+  Services.storage.openUnsharedDatabase(db);
+  Assert.ok(db.exists());
+}
+
+var tests = [
+  test_openUnsharedDatabase_null_file,
+  test_openUnsharedDatabase_file_DNE,
+  test_openUnsharedDatabase_file_exists,
+];
+
+function run_test() {
+  for (var i = 0; i < tests.length; i++) {
+    tests[i]();
+  }
+
+  cleanup();
+}
diff --git a/storage/test/unit/test_storage_statement.js b/storage/test/unit/test_storage_statement.js
new file mode 100644
index 0000000000..3daf3e7812
--- /dev/null
+++ b/storage/test/unit/test_storage_statement.js
@@ -0,0 +1,183 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file tests the functions of mozIStorageStatement
+
+function setup() {
+  getOpenedDatabase().createTable("test", "id INTEGER PRIMARY KEY, name TEXT");
+}
+
+function test_parameterCount_none() {
+  var stmt = createStatement("SELECT * FROM test");
+  Assert.equal(0, stmt.parameterCount);
+  stmt.reset();
+  stmt.finalize();
+}
+
+function test_parameterCount_one() {
+  var stmt = createStatement("SELECT * FROM test WHERE id = ?1");
+  Assert.equal(1, stmt.parameterCount);
+  stmt.reset();
+  stmt.finalize();
+}
+
+function test_getParameterName() {
+  var stmt = createStatement("SELECT * FROM test WHERE id = :id");
+  Assert.equal(":id", stmt.getParameterName(0));
+  stmt.reset();
+  stmt.finalize();
+}
+
+function test_getParameterIndex_different() {
+  var stmt = createStatement(
+    "SELECT * FROM test WHERE id = :id OR name = :name"
+  );
+  Assert.equal(0, stmt.getParameterIndex("id"));
+  Assert.equal(1, stmt.getParameterIndex("name"));
+  stmt.reset();
+  stmt.finalize();
+}
+
+function test_getParameterIndex_same() {
+  var stmt = createStatement(
+    "SELECT * FROM test WHERE id = :test OR name = :test"
+  );
+  Assert.equal(0, stmt.getParameterIndex("test"));
+  stmt.reset();
+  stmt.finalize();
+}
+
+function test_columnCount() {
+  var stmt = createStatement("SELECT * FROM test WHERE id = ?1 OR name = ?2");
+  Assert.equal(2, stmt.columnCount);
+  stmt.reset();
+  stmt.finalize();
+}
+
+function test_getColumnName() {
+  var stmt = createStatement("SELECT name, id FROM test");
+  Assert.equal("id", stmt.getColumnName(1));
+  Assert.equal("name", stmt.getColumnName(0));
+  stmt.reset();
+  stmt.finalize();
+}
+
+function test_getColumnIndex_same_case() {
+  var stmt = createStatement("SELECT name, id FROM test");
+  Assert.equal(0, stmt.getColumnIndex("name"));
+  Assert.equal(1, stmt.getColumnIndex("id"));
+  stmt.reset();
+  stmt.finalize();
+}
+
+function test_getColumnIndex_different_case() {
+  var stmt = createStatement("SELECT name, id FROM test");
+  try {
+    Assert.equal(0, stmt.getColumnIndex("NaMe"));
+    do_throw("should not get here");
+  } catch (e) {
+    Assert.equal(Cr.NS_ERROR_INVALID_ARG, e.result);
+  }
+  try {
+    Assert.equal(1, stmt.getColumnIndex("Id"));
+    do_throw("should not get here");
+  } catch (e) {
+    Assert.equal(Cr.NS_ERROR_INVALID_ARG, e.result);
+  }
+  stmt.reset();
+  stmt.finalize();
+}
+
+function test_state_ready() {
+  var stmt = createStatement("SELECT name, id FROM test");
+  Assert.equal(Ci.mozIStorageStatement.MOZ_STORAGE_STATEMENT_READY, stmt.state);
+  stmt.reset();
+  stmt.finalize();
+}
+
+function test_state_executing() {
+  var stmt = createStatement("INSERT INTO test (name) VALUES ('foo')");
+  stmt.execute();
+  stmt.execute();
+  stmt.finalize();
+
+  stmt = createStatement("SELECT name, id FROM test");
+  stmt.executeStep();
+  Assert.equal(
+    Ci.mozIStorageStatement.MOZ_STORAGE_STATEMENT_EXECUTING,
+    stmt.state
+  );
+  stmt.executeStep();
+  Assert.equal(
+    Ci.mozIStorageStatement.MOZ_STORAGE_STATEMENT_EXECUTING,
+    stmt.state
+  );
+  stmt.reset();
+  Assert.equal(Ci.mozIStorageStatement.MOZ_STORAGE_STATEMENT_READY, stmt.state);
+  stmt.finalize();
+}
+
+function test_state_after_finalize() {
+  var stmt = createStatement("SELECT name, id FROM test");
+  stmt.executeStep();
+  stmt.finalize();
+  Assert.equal(
+    Ci.mozIStorageStatement.MOZ_STORAGE_STATEMENT_INVALID,
+    stmt.state
+  );
+}
+
+function test_failed_execute() {
+  var stmt = createStatement("INSERT INTO test (name) VALUES ('foo')");
+  stmt.execute();
+  stmt.finalize();
+  var id = getOpenedDatabase().lastInsertRowID;
+  stmt = createStatement("INSERT INTO test(id, name) VALUES(:id, 'bar')");
+  stmt.params.id = id;
+  try {
+    // Should throw a constraint error
+    stmt.execute();
+    do_throw("Should have seen a constraint error");
+  } catch (e) {
+    Assert.equal(getOpenedDatabase().lastError, Ci.mozIStorageError.CONSTRAINT);
+  }
+  Assert.equal(Ci.mozIStorageStatement.MOZ_STORAGE_STATEMENT_READY, stmt.state);
+  // Should succeed without needing to reset the statement manually
+  stmt.finalize();
+}
+
+function test_bind_undefined() {
+  var stmt = createStatement("INSERT INTO test (name) VALUES ('foo')");
+
+  expectError(Cr.NS_ERROR_ILLEGAL_VALUE, () => stmt.bindParameters(undefined));
+
+  stmt.finalize();
+}
+
+var tests = [
+  test_parameterCount_none,
+  test_parameterCount_one,
+  test_getParameterName,
+  test_getParameterIndex_different,
+  test_getParameterIndex_same,
+  test_columnCount,
+  test_getColumnName,
+  test_getColumnIndex_same_case,
+  test_getColumnIndex_different_case,
+  test_state_ready,
+  test_state_executing,
+  test_state_after_finalize,
+  test_failed_execute,
+  test_bind_undefined,
+];
+
+function run_test() {
+  setup();
+
+  for (var i = 0; i < tests.length; i++) {
+    tests[i]();
+  }
+
+  cleanup();
+}
diff --git a/storage/test/unit/test_storage_value_array.js b/storage/test/unit/test_storage_value_array.js
new file mode 100644
index 0000000000..6a8f1fb6a2
--- /dev/null
+++ b/storage/test/unit/test_storage_value_array.js
@@ -0,0 +1,194 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file tests the functions of mozIStorageValueArray
+
+add_task(async function setup() {
+  getOpenedDatabase().createTable(
+    "test",
+    "id INTEGER PRIMARY KEY, name TEXT," +
+      "number REAL, nuller NULL, blobber BLOB"
+  );
+
+  var stmt = createStatement(
+    "INSERT INTO test (name, number, blobber) VALUES (?1, ?2, ?3)"
+  );
+  stmt.bindByIndex(0, "foo");
+  stmt.bindByIndex(1, 2.34);
+  stmt.bindBlobByIndex(2, [], 0);
+  stmt.execute();
+
+  stmt.bindByIndex(0, "");
+  stmt.bindByIndex(1, 1.23);
+  stmt.bindBlobByIndex(2, [1, 2], 2);
+  stmt.execute();
+
+  stmt.reset();
+  stmt.finalize();
+
+  registerCleanupFunction(cleanup);
+});
+
+add_task(async function test_getIsNull_for_null() {
+  var stmt = createStatement("SELECT nuller, blobber FROM test WHERE id = ?1");
+  stmt.bindByIndex(0, 1);
+  Assert.ok(stmt.executeStep());
+
+  Assert.ok(stmt.getIsNull(0)); // null field
+  Assert.ok(stmt.getIsNull(1)); // data is null if size is 0
+  stmt.reset();
+  stmt.finalize();
+});
+
+add_task(async function test_getIsNull_for_non_null() {
+  var stmt = createStatement("SELECT name, blobber FROM test WHERE id = ?1");
+  stmt.bindByIndex(0, 2);
+  Assert.ok(stmt.executeStep());
+
+  Assert.ok(!stmt.getIsNull(0));
+  Assert.ok(!stmt.getIsNull(1));
+  stmt.reset();
+  stmt.finalize();
+});
+
+add_task(async function test_value_type_null() {
+  var stmt = createStatement("SELECT nuller FROM test WHERE id = ?1");
+  stmt.bindByIndex(0, 1);
+  Assert.ok(stmt.executeStep());
+
+  Assert.equal(
+    Ci.mozIStorageValueArray.VALUE_TYPE_NULL,
+    stmt.getTypeOfIndex(0)
+  );
+  stmt.reset();
+  stmt.finalize();
+});
+
+add_task(async function test_value_type_integer() {
+  var stmt = createStatement("SELECT id FROM test WHERE id = ?1");
+  stmt.bindByIndex(0, 1);
+  Assert.ok(stmt.executeStep());
+
+  Assert.equal(
+    Ci.mozIStorageValueArray.VALUE_TYPE_INTEGER,
+    stmt.getTypeOfIndex(0)
+  );
+  stmt.reset();
+  stmt.finalize();
+});
+
+add_task(async function test_value_type_float() {
+  var stmt = createStatement("SELECT number FROM test WHERE id = ?1");
+  stmt.bindByIndex(0, 1);
+  Assert.ok(stmt.executeStep());
+
+  Assert.equal(
+    Ci.mozIStorageValueArray.VALUE_TYPE_FLOAT,
+    stmt.getTypeOfIndex(0)
+  );
+  stmt.reset();
+  stmt.finalize();
+});
+
+add_task(async function test_value_type_text() {
+  var stmt = createStatement("SELECT name FROM test WHERE id = ?1");
+  stmt.bindByIndex(0, 1);
+  Assert.ok(stmt.executeStep());
+
+  Assert.equal(
+    Ci.mozIStorageValueArray.VALUE_TYPE_TEXT,
+    stmt.getTypeOfIndex(0)
+  );
+  stmt.reset();
+  stmt.finalize();
+});
+
+add_task(async function test_value_type_blob() {
+  var stmt = createStatement("SELECT blobber FROM test WHERE id = ?1");
+  stmt.bindByIndex(0, 2);
+  Assert.ok(stmt.executeStep());
+
+  Assert.equal(
+    Ci.mozIStorageValueArray.VALUE_TYPE_BLOB,
+    stmt.getTypeOfIndex(0)
+  );
+  stmt.reset();
+  stmt.finalize();
+});
+
+add_task(async function test_numEntries_one() {
+  var stmt = createStatement("SELECT blobber FROM test WHERE id = ?1");
+  stmt.bindByIndex(0, 2);
+  Assert.ok(stmt.executeStep());
+
+  Assert.equal(1, stmt.numEntries);
+  stmt.reset();
+  stmt.finalize();
+});
+
+add_task(async function test_numEntries_all() {
+  var stmt = createStatement("SELECT * FROM test WHERE id = ?1");
+  stmt.bindByIndex(0, 2);
+  Assert.ok(stmt.executeStep());
+
+  Assert.equal(5, stmt.numEntries);
+  stmt.reset();
+  stmt.finalize();
+});
+
+add_task(async function test_getInt() {
+  var stmt = createStatement("SELECT id FROM test WHERE id = ?1");
+  stmt.bindByIndex(0, 2);
+  Assert.ok(stmt.executeStep());
+
+  Assert.equal(2, stmt.getInt32(0));
+  Assert.equal(2, stmt.getInt64(0));
+  stmt.reset();
+  stmt.finalize();
+});
+
+add_task(async function test_getDouble() {
+  var stmt = createStatement("SELECT number FROM test WHERE id = ?1");
+  stmt.bindByIndex(0, 2);
+  Assert.ok(stmt.executeStep());
+
+  Assert.equal(1.23, stmt.getDouble(0));
+  stmt.reset();
+  stmt.finalize();
+});
+
+add_task(async function test_getUTF8String() {
+  var stmt = createStatement("SELECT name FROM test WHERE id = ?1");
+  stmt.bindByIndex(0, 1);
+  Assert.ok(stmt.executeStep());
+
+  Assert.equal("foo", stmt.getUTF8String(0));
+  stmt.reset();
+  stmt.finalize();
+});
+
+add_task(async function test_getString() {
+  var stmt = createStatement("SELECT name FROM test WHERE id = ?1");
+  stmt.bindByIndex(0, 2);
+  Assert.ok(stmt.executeStep());
+
+  Assert.equal("", stmt.getString(0));
+  stmt.reset();
+  stmt.finalize();
+});
+
+add_task(async function test_getBlob() {
+  var stmt = createStatement("SELECT blobber FROM test WHERE id = ?1");
+  stmt.bindByIndex(0, 2);
+  Assert.ok(stmt.executeStep());
+
+  var count = { value: 0 };
+  var arr = { value: null };
+  stmt.getBlob(0, count, arr);
+  Assert.equal(2, count.value);
+  Assert.equal(1, arr.value[0]);
+  Assert.equal(2, arr.value[1]);
+  stmt.reset();
+  stmt.finalize();
+});
diff --git a/storage/test/unit/test_unicode.js b/storage/test/unit/test_unicode.js
new file mode 100644
index 0000000000..0785a54a42
--- /dev/null
+++ b/storage/test/unit/test_unicode.js
@@ -0,0 +1,91 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file tests the unicode functions that we have added
+
+const LATIN1_AE = "\xc6"; // "Æ"
+const LATIN1_ae = "\xe6"; // "æ"
+
+add_task(async function setup() {
+  getOpenedDatabase().createTable("test", "id INTEGER PRIMARY KEY, name TEXT");
+
+  var stmt = createStatement("INSERT INTO test (name, id) VALUES (?1, ?2)");
+  stmt.bindByIndex(0, LATIN1_AE);
+  stmt.bindByIndex(1, 1);
+  stmt.execute();
+  stmt.bindByIndex(0, "A");
+  stmt.bindByIndex(1, 2);
+  stmt.execute();
+  stmt.bindByIndex(0, "b");
+  stmt.bindByIndex(1, 3);
+  stmt.execute();
+  stmt.bindByIndex(0, LATIN1_ae);
+  stmt.bindByIndex(1, 4);
+  stmt.execute();
+  stmt.finalize();
+
+  registerCleanupFunction(cleanup);
+});
+
+add_task(async function test_upper_ascii() {
+  var stmt = createStatement(
+    "SELECT name, id FROM test WHERE name = upper('a')"
+  );
+  Assert.ok(stmt.executeStep());
+  Assert.equal("A", stmt.getString(0));
+  Assert.equal(2, stmt.getInt32(1));
+  stmt.reset();
+  stmt.finalize();
+});
+
+add_task(async function test_upper_non_ascii() {
+  var stmt = createStatement(
+    "SELECT name, id FROM test WHERE name = upper(?1)"
+  );
+  stmt.bindByIndex(0, LATIN1_ae);
+  Assert.ok(stmt.executeStep());
+  Assert.equal(LATIN1_AE, stmt.getString(0));
+  Assert.equal(1, stmt.getInt32(1));
+  stmt.reset();
+  stmt.finalize();
+});
+
+add_task(async function test_lower_ascii() {
+  var stmt = createStatement(
+    "SELECT name, id FROM test WHERE name = lower('B')"
+  );
+  Assert.ok(stmt.executeStep());
+  Assert.equal("b", stmt.getString(0));
+  Assert.equal(3, stmt.getInt32(1));
+  stmt.reset();
+  stmt.finalize();
+});
+
+add_task(async function test_lower_non_ascii() {
+  var stmt = createStatement(
+    "SELECT name, id FROM test WHERE name = lower(?1)"
+  );
+  stmt.bindByIndex(0, LATIN1_AE);
+  Assert.ok(stmt.executeStep());
+  Assert.equal(LATIN1_ae, stmt.getString(0));
+  Assert.equal(4, stmt.getInt32(1));
+  stmt.reset();
+  stmt.finalize();
+});
+
+add_task(async function test_like_search_different() {
+  var stmt = createStatement("SELECT COUNT(*) FROM test WHERE name LIKE ?1");
+  stmt.bindByIndex(0, LATIN1_AE);
+  Assert.ok(stmt.executeStep());
+  Assert.equal(2, stmt.getInt32(0));
+  stmt.finalize();
+});
+
+add_task(async function test_like_search_same() {
+  var stmt = createStatement("SELECT COUNT(*) FROM test WHERE name LIKE ?1");
+  stmt.bindByIndex(0, LATIN1_ae);
+  Assert.ok(stmt.executeStep());
+  Assert.equal(2, stmt.getInt32(0));
+  stmt.finalize();
+});
diff --git a/storage/test/unit/test_vacuum.js b/storage/test/unit/test_vacuum.js
new file mode 100644
index 0000000000..a4cfdf714f
--- /dev/null
+++ b/storage/test/unit/test_vacuum.js
@@ -0,0 +1,372 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+// This file tests the Vacuum Manager and asyncVacuum().
+
+const { VacuumParticipant } = ChromeUtils.importESModule(
+  "resource://testing-common/VacuumParticipant.sys.mjs"
+);
+
+/**
+ * Sends a fake idle-daily notification to the VACUUM Manager.
+ */
+function synthesize_idle_daily() {
+  Cc["@mozilla.org/storage/vacuum;1"]
+    .getService(Ci.nsIObserver)
+    .observe(null, "idle-daily", null);
+}
+
+/**
+ * Returns a new nsIFile reference for a profile database.
+ * @param filename for the database, excluded the .sqlite extension.
+ */
+function new_db_file(name = "testVacuum") {
+  let file = Services.dirsvc.get("ProfD", Ci.nsIFile);
+  file.append(name + ".sqlite");
+  return file;
+}
+
+function reset_vacuum_date(name = "testVacuum") {
+  let date = parseInt(Date.now() / 1000 - 31 * 86400);
+  // Set last VACUUM to a date in the past.
+  Services.prefs.setIntPref(`storage.vacuum.last.${name}.sqlite`, date);
+  return date;
+}
+
+function get_vacuum_date(name = "testVacuum") {
+  return Services.prefs.getIntPref(`storage.vacuum.last.${name}.sqlite`, 0);
+}
+
+add_setup(async function () {
+  // turn on Cu.isInAutomation
+  Services.prefs.setBoolPref(
+    "security.turn_off_all_security_so_that_viruses_can_take_over_this_computer",
+    true
+  );
+});
+
+add_task(async function test_common_vacuum() {
+  let last_vacuum_date = reset_vacuum_date();
+  info("Test that a VACUUM correctly happens and all notifications are fired.");
+  let promiseTestVacuumBegin = TestUtils.topicObserved("test-begin-vacuum");
+  let promiseTestVacuumEnd = TestUtils.topicObserved("test-end-vacuum-success");
+  let promiseVacuumBegin = TestUtils.topicObserved("vacuum-begin");
+  let promiseVacuumEnd = TestUtils.topicObserved("vacuum-end");
+
+  let participant = new VacuumParticipant(
+    Services.storage.openDatabase(new_db_file())
+  );
+  await participant.promiseRegistered();
+  synthesize_idle_daily();
+  // Wait for notifications.
+  await Promise.all([
+    promiseTestVacuumBegin,
+    promiseTestVacuumEnd,
+    promiseVacuumBegin,
+    promiseVacuumEnd,
+  ]);
+  Assert.greater(get_vacuum_date(), last_vacuum_date);
+  await participant.dispose();
+});
+
+add_task(async function test_skipped_if_recent_vacuum() {
+  info("Test that a VACUUM is skipped if it was run recently.");
+  Services.prefs.setIntPref(
+    "storage.vacuum.last.testVacuum.sqlite",
+    parseInt(Date.now() / 1000)
+  );
+  // Wait for VACUUM skipped notification.
+  let promiseSkipped = TestUtils.topicObserved("vacuum-skip");
+
+  let participant = new VacuumParticipant(
+    Services.storage.openDatabase(new_db_file())
+  );
+  await participant.promiseRegistered();
+  synthesize_idle_daily();
+
+  // Check that VACUUM has been skipped.
+  await promiseSkipped;
+
+  await participant.dispose();
+});
+
+add_task(async function test_page_size_change() {
+  info("Test that a VACUUM changes page_size");
+  reset_vacuum_date();
+
+  let conn = Services.storage.openDatabase(new_db_file());
+  info("Check initial page size.");
+  let stmt = conn.createStatement("PRAGMA page_size");
+  Assert.ok(stmt.executeStep());
+  Assert.equal(stmt.row.page_size, conn.defaultPageSize);
+  stmt.finalize();
+  await populateFreeList(conn);
+
+  let participant = new VacuumParticipant(conn, { expectedPageSize: 1024 });
+  await participant.promiseRegistered();
+  let promiseVacuumEnd = TestUtils.topicObserved("test-end-vacuum-success");
+  synthesize_idle_daily();
+  await promiseVacuumEnd;
+
+  info("Check that page size was updated.");
+  stmt = conn.createStatement("PRAGMA page_size");
+  Assert.ok(stmt.executeStep());
+  Assert.equal(stmt.row.page_size, 1024);
+  stmt.finalize();
+
+  await participant.dispose();
+});
+
+add_task(async function test_skipped_optout_vacuum() {
+  info("Test that a VACUUM is skipped if the participant wants to opt-out.");
+  reset_vacuum_date();
+
+  let participant = new VacuumParticipant(
+    Services.storage.openDatabase(new_db_file()),
+    { grant: false }
+  );
+  await participant.promiseRegistered();
+  // Wait for VACUUM skipped notification.
+  let promiseSkipped = TestUtils.topicObserved("vacuum-skip");
+
+  synthesize_idle_daily();
+
+  // Check that VACUUM has been skipped.
+  await promiseSkipped;
+
+  await participant.dispose();
+});
+
+add_task(async function test_memory_database_crash() {
+  info("Test that we don't crash trying to vacuum a memory database");
+  reset_vacuum_date();
+
+  let participant = new VacuumParticipant(
+    Services.storage.openSpecialDatabase("memory")
+  );
+  await participant.promiseRegistered();
+  // Wait for VACUUM skipped notification.
+  let promiseSkipped = TestUtils.topicObserved("vacuum-skip");
+
+  synthesize_idle_daily();
+
+  // Check that VACUUM has been skipped.
+  await promiseSkipped;
+
+  await participant.dispose();
+});
+
+add_task(async function test_async_connection() {
+  info("Test we can vacuum an async connection");
+  reset_vacuum_date();
+
+  let conn = await openAsyncDatabase(new_db_file());
+  await populateFreeList(conn);
+  let participant = new VacuumParticipant(conn);
+  await participant.promiseRegistered();
+
+  let promiseVacuumEnd = TestUtils.topicObserved("test-end-vacuum-success");
+  synthesize_idle_daily();
+  await promiseVacuumEnd;
+
+  await participant.dispose();
+});
+
+add_task(async function test_change_to_incremental_vacuum() {
+  info("Test we can change to incremental vacuum");
+  reset_vacuum_date();
+
+  let conn = Services.storage.openDatabase(new_db_file());
+  info("Check initial vacuum.");
+  let stmt = conn.createStatement("PRAGMA auto_vacuum");
+  Assert.ok(stmt.executeStep());
+  Assert.equal(stmt.row.auto_vacuum, 0);
+  stmt.finalize();
+  await populateFreeList(conn);
+
+  let participant = new VacuumParticipant(conn, { useIncrementalVacuum: true });
+  await participant.promiseRegistered();
+  let promiseVacuumEnd = TestUtils.topicObserved("test-end-vacuum-success");
+  synthesize_idle_daily();
+  await promiseVacuumEnd;
+
+  info("Check that auto_vacuum was updated.");
+  stmt = conn.createStatement("PRAGMA auto_vacuum");
+  Assert.ok(stmt.executeStep());
+  Assert.equal(stmt.row.auto_vacuum, 2);
+  stmt.finalize();
+
+  await participant.dispose();
+});
+
+add_task(async function test_change_from_incremental_vacuum() {
+  info("Test we can change from incremental vacuum");
+  reset_vacuum_date();
+
+  let conn = Services.storage.openDatabase(new_db_file());
+  conn.executeSimpleSQL("PRAGMA auto_vacuum = 2");
+  info("Check initial vacuum.");
+  let stmt = conn.createStatement("PRAGMA auto_vacuum");
+  Assert.ok(stmt.executeStep());
+  Assert.equal(stmt.row.auto_vacuum, 2);
+  stmt.finalize();
+  await populateFreeList(conn);
+
+  let participant = new VacuumParticipant(conn, {
+    useIncrementalVacuum: false,
+  });
+  await participant.promiseRegistered();
+  let promiseVacuumEnd = TestUtils.topicObserved("test-end-vacuum-success");
+  synthesize_idle_daily();
+  await promiseVacuumEnd;
+
+  info("Check that auto_vacuum was updated.");
+  stmt = conn.createStatement("PRAGMA auto_vacuum");
+  Assert.ok(stmt.executeStep());
+  Assert.equal(stmt.row.auto_vacuum, 0);
+  stmt.finalize();
+
+  await participant.dispose();
+});
+
+add_task(async function test_attached_vacuum() {
+  info("Test attached database is not a problem");
+  reset_vacuum_date();
+
+  let conn = Services.storage.openDatabase(new_db_file());
+  let conn2 = Services.storage.openDatabase(new_db_file("attached"));
+
+  info("Attach " + conn2.databaseFile.path);
+  conn.executeSimpleSQL(
+    `ATTACH DATABASE '${conn2.databaseFile.path}' AS attached`
+  );
+  await asyncClose(conn2);
+  let stmt = conn.createStatement("PRAGMA database_list");
+  let schemas = [];
+  while (stmt.executeStep()) {
+    schemas.push(stmt.row.name);
+  }
+  Assert.deepEqual(schemas, ["main", "attached"]);
+  stmt.finalize();
+
+  await populateFreeList(conn);
+  await populateFreeList(conn, "attached");
+
+  let participant = new VacuumParticipant(conn);
+  await participant.promiseRegistered();
+  let promiseVacuumEnd = TestUtils.topicObserved("test-end-vacuum-success");
+  synthesize_idle_daily();
+  await promiseVacuumEnd;
+
+  await participant.dispose();
+});
+
+add_task(async function test_vacuum_fail() {
+  info("Test a failed vacuum");
+  reset_vacuum_date();
+
+  let conn = Services.storage.openDatabase(new_db_file());
+  // Cannot vacuum in a transaction.
+  conn.beginTransaction();
+  await populateFreeList(conn);
+
+  let participant = new VacuumParticipant(conn);
+  await participant.promiseRegistered();
+  let promiseVacuumEnd = TestUtils.topicObserved("test-end-vacuum-failure");
+  synthesize_idle_daily();
+  await promiseVacuumEnd;
+
+  conn.commitTransaction();
+  await participant.dispose();
+});
+
+add_task(async function test_async_vacuum() {
+  // Since previous tests already go through most cases, this only checks
+  // the basics of directly calling asyncVacuum().
+  info("Test synchronous connection");
+  let conn = Services.storage.openDatabase(new_db_file());
+  await populateFreeList(conn);
+  let rv = await new Promise(resolve => {
+    conn.asyncVacuum(status => {
+      resolve(status);
+    });
+  });
+  Assert.ok(Components.isSuccessCode(rv));
+  await asyncClose(conn);
+
+  info("Test asynchronous connection");
+  conn = await openAsyncDatabase(new_db_file());
+  await populateFreeList(conn);
+  rv = await new Promise(resolve => {
+    conn.asyncVacuum(status => {
+      resolve(status);
+    });
+  });
+  Assert.ok(Components.isSuccessCode(rv));
+  await asyncClose(conn);
+});
+
+// Chunked growth is disabled on Android, so this test is pointless there.
+add_task(
+  { skip_if: () => AppConstants.platform == "android" },
+  async function test_vacuum_growth() {
+    // Tests vacuum doesn't nullify chunked growth.
+    let conn = Services.storage.openDatabase(new_db_file("incremental"));
+    conn.executeSimpleSQL("PRAGMA auto_vacuum = INCREMENTAL");
+    conn.setGrowthIncrement(2 * conn.defaultPageSize, "");
+    await populateFreeList(conn);
+    let stmt = conn.createStatement("PRAGMA freelist_count");
+    let count = 0;
+    Assert.ok(stmt.executeStep());
+    count = stmt.row.freelist_count;
+    stmt.reset();
+    Assert.greater(count, 2, "There's more than 2 page in freelist");
+
+    let rv = await new Promise(resolve => {
+      conn.asyncVacuum(status => {
+        resolve(status);
+      }, true);
+    });
+    Assert.ok(Components.isSuccessCode(rv));
+
+    Assert.ok(stmt.executeStep());
+    Assert.equal(
+      stmt.row.freelist_count,
+      2,
+      "chunked growth space was preserved"
+    );
+    stmt.reset();
+
+    // A full vacuuum should not be executed if there's less free pages than
+    // chunked growth.
+    rv = await new Promise(resolve => {
+      conn.asyncVacuum(status => {
+        resolve(status);
+      });
+    });
+    Assert.ok(Components.isSuccessCode(rv));
+
+    Assert.ok(stmt.executeStep());
+    Assert.equal(
+      stmt.row.freelist_count,
+      2,
+      "chunked growth space was preserved"
+    );
+    stmt.finalize();
+
+    await asyncClose(conn);
+  }
+);
+
+async function populateFreeList(conn, schema = "main") {
+  await executeSimpleSQLAsync(conn, `CREATE TABLE ${schema}.test (id TEXT)`);
+  await executeSimpleSQLAsync(
+    conn,
+    `INSERT INTO ${schema}.test
+     VALUES ${Array.from({ length: 3000 }, () => Math.random()).map(
+       v => "('" + v + "')"
+     )}`
+  );
+  await executeSimpleSQLAsync(conn, `DROP TABLE ${schema}.test`);
+}
diff --git a/storage/test/unit/xpcshell.toml b/storage/test/unit/xpcshell.toml
new file mode 100644
index 0000000000..2560bf3281
--- /dev/null
+++ b/storage/test/unit/xpcshell.toml
@@ -0,0 +1,96 @@
+[DEFAULT]
+head = "head_storage.js"
+support-files = [
+  "baddataDB.sqlite",
+  "corruptDB.sqlite",
+  "fakeDB.sqlite",
+  "goodDB.sqlite",
+  "locale_collation.txt",
+  "VacuumParticipant.sys.mjs",
+]
+
+["test_bug-365166.js"]
+
+["test_bug-393952.js"]
+
+["test_bug-429521.js"]
+
+["test_bug-444233.js"]
+
+["test_cache_size.js"]
+
+["test_chunk_growth.js"]
+# Bug 676981: test fails consistently on Android
+fail-if = ["os == 'android'"]
+
+["test_connection_asyncClose.js"]
+
+["test_connection_executeAsync.js"]
+
+["test_connection_executeSimpleSQLAsync.js"]
+
+["test_connection_failsafe_close.js"]
+# The failsafe close mechanism asserts when performing SpinningSynchronousClose
+# on debug builds, so we can only test on non-debug builds.
+skip-if = ["debug"]
+
+["test_connection_interrupt.js"]
+
+["test_connection_online_backup.js"]
+
+["test_default_journal_size_limit.js"]
+
+["test_js_helpers.js"]
+
+["test_levenshtein.js"]
+
+["test_like.js"]
+
+["test_like_escape.js"]
+
+["test_locale_collation.js"]
+
+["test_minimizeMemory.js"]
+
+["test_page_size_is_32k.js"]
+
+["test_persist_journal.js"]
+
+["test_readonly-immutable-nolock_vfs.js"]
+
+["test_retry_on_busy.js"]
+
+["test_sqlite_secure_delete.js"]
+
+["test_statement_executeAsync.js"]
+
+["test_statement_wrapper_automatically.js"]
+
+["test_storage_connection.js"]
+# Bug 676981: test fails consistently on Android
+fail-if = ["os == 'android'"]
+
+["test_storage_ext.js"]
+
+["test_storage_ext_fts3.js"]
+skip-if = ["appname != 'thunderbird' && appname != 'seamonkey'"]
+
+["test_storage_ext_fts5.js"]
+
+["test_storage_function.js"]
+
+["test_storage_progresshandler.js"]
+
+["test_storage_service.js"]
+
+["test_storage_service_special.js"]
+
+["test_storage_service_unshared.js"]
+
+["test_storage_statement.js"]
+
+["test_storage_value_array.js"]
+
+["test_unicode.js"]
+
+["test_vacuum.js"]
diff --git a/storage/variant/Cargo.toml b/storage/variant/Cargo.toml
new file mode 100644
index 0000000000..26e30ea1ce
--- /dev/null
+++ b/storage/variant/Cargo.toml
@@ -0,0 +1,14 @@
+[package]
+name = "storage_variant"
+version = "0.1.0"
+authors = [
+    "Lina Cambridge <lina@yakshaving.ninja>",
+    "Myk Melez <myk@mykzilla.org>"
+]
+license = "MPL-2.0"
+
+[dependencies]
+libc = "0.2"
+nserror = { path = "../../xpcom/rust/nserror" }
+nsstring = { path = "../../xpcom/rust/nsstring" }
+xpcom = { path = "../../xpcom/rust/xpcom" }
diff --git a/storage/variant/src/bag.rs b/storage/variant/src/bag.rs
new file mode 100644
index 0000000000..91653ba226
--- /dev/null
+++ b/storage/variant/src/bag.rs
@@ -0,0 +1,135 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use nserror::{nsresult, NS_ERROR_CANNOT_CONVERT_DATA, NS_OK};
+use nsstring::nsString;
+use xpcom::{
+    getter_addrefs,
+    interfaces::{nsIProperty, nsIPropertyBag, nsIWritablePropertyBag},
+    RefPtr, XpCom,
+};
+
+use crate::{NsIVariantExt, VariantType};
+
+extern "C" {
+    fn NS_NewHashPropertyBag(bag: *mut *const nsIWritablePropertyBag);
+}
+
+/// A hash property bag backed by storage variant values.
+pub struct HashPropertyBag(RefPtr<nsIWritablePropertyBag>);
+
+// This is safe as long as our `nsIWritablePropertyBag` is an instance of
+// `mozilla::nsHashPropertyBag`, which is atomically reference counted, and
+// all properties are backed by `Storage*Variant`s, all of which are
+// thread-safe.
+unsafe impl Send for HashPropertyBag {}
+unsafe impl Sync for HashPropertyBag {}
+
+impl Default for HashPropertyBag {
+    fn default() -> HashPropertyBag {
+        // This is safe to unwrap because `NS_NewHashPropertyBag` is infallible.
+        let bag = getter_addrefs(|p| {
+            unsafe { NS_NewHashPropertyBag(p) };
+            NS_OK
+        })
+        .unwrap();
+        HashPropertyBag(bag)
+    }
+}
+
+impl HashPropertyBag {
+    /// Creates an empty property bag.
+    #[inline]
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Creates a property bag from an instance of `nsIPropertyBag`, cloning its
+    /// contents. The `source` bag can only contain primitive values for which
+    /// the `VariantType` trait is implemented. Attempting to clone a bag with
+    /// unsupported types, such as arrays, interface pointers, and `jsval`s,
+    /// fails with `NS_ERROR_CANNOT_CONVERT_DATA`.
+    ///
+    /// `clone_from_bag` can be used to clone a thread-unsafe `nsIPropertyBag`,
+    /// like one passed from JavaScript via XPConnect, into one that can be
+    /// shared across threads.
+    pub fn clone_from_bag(source: &nsIPropertyBag) -> Result<Self, nsresult> {
+        let enumerator = getter_addrefs(|p| unsafe { source.GetEnumerator(p) })?;
+        let b = HashPropertyBag::new();
+        while {
+            let mut has_more = false;
+            unsafe { enumerator.HasMoreElements(&mut has_more) }.to_result()?;
+            has_more
+        } {
+            let element = getter_addrefs(|p| unsafe { enumerator.GetNext(p) })?;
+            let property = element
+                .query_interface::<nsIProperty>()
+                .ok_or(NS_ERROR_CANNOT_CONVERT_DATA)?;
+            let mut name = nsString::new();
+            unsafe { property.GetName(&mut *name) }.to_result()?;
+            let value = getter_addrefs(|p| unsafe { property.GetValue(p) })?;
+            unsafe { b.0.SetProperty(&*name, value.try_clone()?.coerce()) }.to_result()?;
+        }
+        Ok(b)
+    }
+
+    /// Returns the value for a property name. Fails with `NS_ERROR_FAILURE`
+    /// if the property doesn't exist, or `NS_ERROR_CANNOT_CONVERT_DATA` if the
+    /// property exists, but is not of the value type `V`.
+    pub fn get<K, V>(&self, name: K) -> Result<V, nsresult>
+    where
+        K: AsRef<str>,
+        V: VariantType,
+    {
+        getter_addrefs(|p| unsafe { self.0.GetProperty(&*nsString::from(name.as_ref()), p) })
+            .and_then(|v| V::from_variant(v.coerce()))
+    }
+
+    /// Returns the value for a property name, or the default if not set or
+    /// not of the value type `V`.
+    #[inline]
+    pub fn get_or_default<K, V>(&self, name: K) -> V
+    where
+        K: AsRef<str>,
+        V: VariantType + Default,
+    {
+        self.get(name).unwrap_or_default()
+    }
+
+    /// Sets a property with the name to the value, overwriting any previous
+    /// value.
+    pub fn set<K, V>(&mut self, name: K, value: V)
+    where
+        K: AsRef<str>,
+        V: VariantType,
+    {
+        let v = value.into_variant();
+        unsafe {
+            // This is safe to unwrap because
+            // `nsHashPropertyBagBase::SetProperty` only returns an error if `v`
+            // is a null pointer.
+            self.0
+                .SetProperty(&*nsString::from(name.as_ref()), v.coerce())
+                .to_result()
+                .unwrap()
+        }
+    }
+
+    /// Deletes a property with the name. Returns `true` if the property
+    /// was previously in the bag, `false` if not.
+    pub fn delete(&mut self, name: impl AsRef<str>) -> bool {
+        unsafe {
+            self.0
+                .DeleteProperty(&*nsString::from(name.as_ref()))
+                .to_result()
+                .is_ok()
+        }
+    }
+
+    /// Returns a reference to the backing `nsIWritablePropertyBag`.
+    #[inline]
+    pub fn bag(&self) -> &nsIWritablePropertyBag {
+        &self.0
+    }
+}
diff --git a/storage/variant/src/lib.rs b/storage/variant/src/lib.rs
new file mode 100644
index 0000000000..4734705299
--- /dev/null
+++ b/storage/variant/src/lib.rs
@@ -0,0 +1,230 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+extern crate libc;
+extern crate nserror;
+extern crate nsstring;
+extern crate xpcom;
+
+mod bag;
+
+use std::{
+    borrow::Cow,
+    convert::{TryFrom, TryInto},
+};
+
+use libc::c_double;
+use nserror::{nsresult, NS_ERROR_CANNOT_CONVERT_DATA, NS_OK};
+use nsstring::{nsACString, nsAString, nsCString, nsString};
+use xpcom::{getter_addrefs, interfaces::nsIVariant, RefPtr};
+
+pub use crate::bag::HashPropertyBag;
+
+extern "C" {
+    fn NS_GetDataType(variant: *const nsIVariant) -> u16;
+    fn NS_NewStorageNullVariant(result: *mut *const nsIVariant);
+    fn NS_NewStorageBooleanVariant(value: bool, result: *mut *const nsIVariant);
+    fn NS_NewStorageIntegerVariant(value: i64, result: *mut *const nsIVariant);
+    fn NS_NewStorageFloatVariant(value: c_double, result: *mut *const nsIVariant);
+    fn NS_NewStorageTextVariant(value: *const nsAString, result: *mut *const nsIVariant);
+    fn NS_NewStorageUTF8TextVariant(value: *const nsACString, result: *mut *const nsIVariant);
+}
+
+// These are the relevant parts of the nsXPTTypeTag enum in xptinfo.h,
+// which nsIVariant.idl reflects into the nsIDataType struct class and uses
+// to constrain the values of nsIVariant::dataType.
+#[repr(u16)]
+#[derive(Debug, Copy, Clone, Eq, Hash, PartialEq)]
+pub enum DataType {
+    Int32 = 2,
+    Int64 = 3,
+    Double = 9,
+    Bool = 10,
+    Void = 13,
+    CharStr = 15,
+    WCharStr = 16,
+    StringSizeIs = 20,
+    WStringSizeIs = 21,
+    Utf8String = 24,
+    CString = 25,
+    AString = 26,
+    EmptyArray = 254,
+    Empty = 255,
+}
+
+impl TryFrom<u16> for DataType {
+    type Error = nsresult;
+
+    /// Converts a raw type tag for an `nsIVariant` into a `DataType` variant.
+    /// Returns `NS_ERROR_CANNOT_CONVERT_DATA` if the type isn't one that we
+    /// support.
+    fn try_from(raw: u16) -> Result<Self, Self::Error> {
+        Ok(match raw {
+            2 => DataType::Int32,
+            3 => DataType::Int64,
+            9 => DataType::Double,
+            10 => DataType::Bool,
+            13 => DataType::Void,
+            15 => DataType::CharStr,
+            16 => DataType::WCharStr,
+            20 => DataType::StringSizeIs,
+            21 => DataType::WStringSizeIs,
+            24 => DataType::Utf8String,
+            25 => DataType::CString,
+            26 => DataType::AString,
+            254 => DataType::EmptyArray,
+            255 => DataType::Empty,
+            _ => Err(NS_ERROR_CANNOT_CONVERT_DATA)?,
+        })
+    }
+}
+
+/// Extension methods implemented on `nsIVariant` types, to make them easier
+/// to work with.
+pub trait NsIVariantExt {
+    /// Returns the raw type tag for this variant. Call
+    /// `DataType::try_from()` on this tag to turn it into a `DataType`.
+    fn get_data_type(&self) -> u16;
+
+    /// Tries to clone this variant, failing with `NS_ERROR_CANNOT_CONVERT_DATA`
+    /// if its type is unsupported.
+    fn try_clone(&self) -> Result<RefPtr<nsIVariant>, nsresult>;
+}
+
+impl NsIVariantExt for nsIVariant {
+    fn get_data_type(&self) -> u16 {
+        unsafe { NS_GetDataType(self) }
+    }
+
+    fn try_clone(&self) -> Result<RefPtr<nsIVariant>, nsresult> {
+        Ok(match self.get_data_type().try_into()? {
+            DataType::Bool => bool::from_variant(self)?.into_variant(),
+            DataType::Int32 => i32::from_variant(self)?.into_variant(),
+            DataType::Int64 => i64::from_variant(self)?.into_variant(),
+            DataType::Double => f64::from_variant(self)?.into_variant(),
+            DataType::AString | DataType::WCharStr | DataType::WStringSizeIs => {
+                nsString::from_variant(self)?.into_variant()
+            }
+            DataType::CString
+            | DataType::CharStr
+            | DataType::StringSizeIs
+            | DataType::Utf8String => nsCString::from_variant(self)?.into_variant(),
+            DataType::Void | DataType::EmptyArray | DataType::Empty => ().into_variant(),
+        })
+    }
+}
+
+pub trait VariantType {
+    fn type_name() -> Cow<'static, str>;
+    fn into_variant(self) -> RefPtr<nsIVariant>;
+    fn from_variant(variant: &nsIVariant) -> Result<Self, nsresult>
+    where
+        Self: Sized;
+}
+
+/// Implements traits to convert between variants and their types.
+macro_rules! variant {
+    ($typ:ident, $constructor:ident, $getter:ident) => {
+        impl VariantType for $typ {
+            fn type_name() -> Cow<'static, str> {
+                stringify!($typ).into()
+            }
+            fn into_variant(self) -> RefPtr<nsIVariant> {
+                // getter_addrefs returns a Result<RefPtr<T>, nsresult>,
+                // but we know that our $constructor is infallible, so we can
+                // safely unwrap and return the RefPtr.
+                getter_addrefs(|p| {
+                    unsafe { $constructor(self.into(), p) };
+                    NS_OK
+                })
+                .unwrap()
+            }
+            fn from_variant(variant: &nsIVariant) -> Result<$typ, nsresult> {
+                let mut result = $typ::default();
+                let rv = unsafe { variant.$getter(&mut result) };
+                if rv.succeeded() {
+                    Ok(result)
+                } else {
+                    Err(rv)
+                }
+            }
+        }
+    };
+    (* $typ:ident, $constructor:ident, $getter:ident) => {
+        impl VariantType for $typ {
+            fn type_name() -> Cow<'static, str> {
+                stringify!($typ).into()
+            }
+            fn into_variant(self) -> RefPtr<nsIVariant> {
+                // getter_addrefs returns a Result<RefPtr<T>, nsresult>,
+                // but we know that our $constructor is infallible, so we can
+                // safely unwrap and return the RefPtr.
+                getter_addrefs(|p| {
+                    unsafe { $constructor(&*self, p) };
+                    NS_OK
+                })
+                .unwrap()
+            }
+            fn from_variant(variant: &nsIVariant) -> Result<$typ, nsresult> {
+                let mut result = $typ::new();
+                let rv = unsafe { variant.$getter(&mut *result) };
+                if rv.succeeded() {
+                    Ok(result)
+                } else {
+                    Err(rv)
+                }
+            }
+        }
+    };
+}
+
+// The unit type (()) is a reasonable equivalation of the null variant.
+// The macro can't produce its implementations of VariantType, however,
+// so we implement them concretely.
+impl VariantType for () {
+    fn type_name() -> Cow<'static, str> {
+        "()".into()
+    }
+    fn into_variant(self) -> RefPtr<nsIVariant> {
+        // getter_addrefs returns a Result<RefPtr<T>, nsresult>,
+        // but we know that NS_NewStorageNullVariant is infallible, so we can
+        // safely unwrap and return the RefPtr.
+        getter_addrefs(|p| {
+            unsafe { NS_NewStorageNullVariant(p) };
+            NS_OK
+        })
+        .unwrap()
+    }
+    fn from_variant(_variant: &nsIVariant) -> Result<Self, nsresult> {
+        Ok(())
+    }
+}
+
+impl<T> VariantType for Option<T>
+where
+    T: VariantType,
+{
+    fn type_name() -> Cow<'static, str> {
+        format!("Option<{}>", T::type_name()).into()
+    }
+    fn into_variant(self) -> RefPtr<nsIVariant> {
+        match self {
+            Some(v) => v.into_variant(),
+            None => ().into_variant(),
+        }
+    }
+    fn from_variant(variant: &nsIVariant) -> Result<Self, nsresult> {
+        Ok(match variant.get_data_type().try_into() {
+            Ok(DataType::Void) | Ok(DataType::EmptyArray) | Ok(DataType::Empty) => None,
+            _ => Some(VariantType::from_variant(variant)?),
+        })
+    }
+}
+
+variant!(bool, NS_NewStorageBooleanVariant, GetAsBool);
+variant!(i32, NS_NewStorageIntegerVariant, GetAsInt32);
+variant!(i64, NS_NewStorageIntegerVariant, GetAsInt64);
+variant!(f64, NS_NewStorageFloatVariant, GetAsDouble);
+variant!(*nsString, NS_NewStorageTextVariant, GetAsAString);
+variant!(*nsCString, NS_NewStorageUTF8TextVariant, GetAsAUTF8String);
diff --git a/storage/variantToSQLiteT_impl.h b/storage/variantToSQLiteT_impl.h
new file mode 100644
index 0000000000..cadaa3f176
--- /dev/null
+++ b/storage/variantToSQLiteT_impl.h
@@ -0,0 +1,114 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Note: we are already in the namepace mozilla::storage
+
+// Note 2: whoever #includes this file must provide implementations of
+// sqlite3_T_* prior.
+
+////////////////////////////////////////////////////////////////////////////////
+//// variantToSQLiteT Implementation
+
+template <typename T>
+int variantToSQLiteT(T aObj, nsIVariant* aValue) {
+  // Allow to return nullptr not wrapped to nsIVariant for speed.
+  if (!aValue) return sqlite3_T_null(aObj);
+
+  uint16_t valueType = aValue->GetDataType();
+  switch (valueType) {
+    case nsIDataType::VTYPE_INT8:
+    case nsIDataType::VTYPE_INT16:
+    case nsIDataType::VTYPE_INT32:
+    case nsIDataType::VTYPE_UINT8:
+    case nsIDataType::VTYPE_UINT16: {
+      int32_t value;
+      nsresult rv = aValue->GetAsInt32(&value);
+      NS_ENSURE_SUCCESS(rv, SQLITE_MISMATCH);
+      return sqlite3_T_int(aObj, value);
+    }
+    case nsIDataType::VTYPE_UINT32:  // Try to preserve full range
+    case nsIDataType::VTYPE_INT64:
+    // Data loss possible, but there is no unsigned types in SQLite
+    case nsIDataType::VTYPE_UINT64: {
+      int64_t value;
+      nsresult rv = aValue->GetAsInt64(&value);
+      NS_ENSURE_SUCCESS(rv, SQLITE_MISMATCH);
+      return sqlite3_T_int64(aObj, value);
+    }
+    case nsIDataType::VTYPE_FLOAT:
+    case nsIDataType::VTYPE_DOUBLE: {
+      double value;
+      nsresult rv = aValue->GetAsDouble(&value);
+      NS_ENSURE_SUCCESS(rv, SQLITE_MISMATCH);
+      return sqlite3_T_double(aObj, value);
+    }
+    case nsIDataType::VTYPE_BOOL: {
+      bool value;
+      nsresult rv = aValue->GetAsBool(&value);
+      NS_ENSURE_SUCCESS(rv, SQLITE_MISMATCH);
+      return sqlite3_T_int(aObj, value ? 1 : 0);
+    }
+    case nsIDataType::VTYPE_CHAR:
+    case nsIDataType::VTYPE_CHAR_STR:
+    case nsIDataType::VTYPE_STRING_SIZE_IS:
+    case nsIDataType::VTYPE_UTF8STRING:
+    case nsIDataType::VTYPE_CSTRING: {
+      nsAutoCString value;
+      // GetAsAUTF8String should never perform conversion when coming from
+      // 8-bit string types, and thus can accept strings with arbitrary encoding
+      // (including UTF8 and ASCII).
+      nsresult rv = aValue->GetAsAUTF8String(value);
+      NS_ENSURE_SUCCESS(rv, SQLITE_MISMATCH);
+      return sqlite3_T_text(aObj, value);
+    }
+    case nsIDataType::VTYPE_WCHAR:
+    case nsIDataType::VTYPE_WCHAR_STR:
+    case nsIDataType::VTYPE_WSTRING_SIZE_IS:
+    case nsIDataType::VTYPE_ASTRING: {
+      nsAutoString value;
+      // GetAsAString does proper conversion to UCS2 from all string-like types.
+      // It can be used universally without problems (unless someone implements
+      // their own variant, but that's their problem).
+      nsresult rv = aValue->GetAsAString(value);
+      NS_ENSURE_SUCCESS(rv, SQLITE_MISMATCH);
+      return sqlite3_T_text16(aObj, value);
+    }
+    case nsIDataType::VTYPE_VOID:
+    case nsIDataType::VTYPE_EMPTY:
+    case nsIDataType::VTYPE_EMPTY_ARRAY:
+      return sqlite3_T_null(aObj);
+    case nsIDataType::VTYPE_ARRAY: {
+      uint16_t arrayType;
+      nsIID iid;
+      uint32_t count;
+      void* data;
+      nsresult rv = aValue->GetAsArray(&arrayType, &iid, &count, &data);
+      NS_ENSURE_SUCCESS(rv, SQLITE_MISMATCH);
+
+      // Check to make sure it's a supported type.
+      NS_ASSERTION(arrayType == nsIDataType::VTYPE_UINT8,
+                   "Invalid type passed!  You may leak!");
+      if (arrayType != nsIDataType::VTYPE_UINT8) {
+        // Technically this could leak with certain data types, but somebody was
+        // being stupid passing us this anyway.
+        free(data);
+        return SQLITE_MISMATCH;
+      }
+
+      // Finally do our thing.  The function should free the array accordingly!
+      int rc = sqlite3_T_blob(aObj, data, count);
+      return rc;
+    }
+    // Maybe, it'll be possible to convert these
+    // in future too.
+    case nsIDataType::VTYPE_ID:
+    case nsIDataType::VTYPE_INTERFACE:
+    case nsIDataType::VTYPE_INTERFACE_IS:
+    default:
+      return SQLITE_MISMATCH;
+  }
+  return SQLITE_OK;
+}