1 files changed, 988 insertions, 0 deletions
diff --git a/netwerk/base/nsFileStreams.cpp b/netwerk/base/nsFileStreams.cpp
new file mode 100644
index 0000000000..f574d13f82
--- /dev/null
+++ b/netwerk/base/nsFileStreams.cpp
@@ -0,0 +1,988 @@
+/* -*- 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/. */
+
+#include "ipc/IPCMessageUtils.h"
+
+#if defined(XP_UNIX)
+#  include <unistd.h>
+#elif defined(XP_WIN)
+#  include <windows.h>
+#  include "nsILocalFileWin.h"
+#else
+// XXX add necessary include file for ftruncate (or equivalent)
+#endif
+
+#include "private/pprio.h"
+#include "prerror.h"
+
+#include "IOActivityMonitor.h"
+#include "nsFileStreams.h"
+#include "nsIFile.h"
+#include "nsReadLine.h"
+#include "nsIClassInfoImpl.h"
+#include "nsLiteralString.h"
+#include "nsSocketTransport2.h"  // for ErrorAccordingToNSPR()
+#include "mozilla/ipc/InputStreamUtils.h"
+#include "mozilla/ipc/RandomAccessStreamParams.h"
+#include "mozilla/Unused.h"
+#include "mozilla/FileUtils.h"
+#include "nsNetCID.h"
+#include "nsXULAppAPI.h"
+
+using FileHandleType = mozilla::ipc::FileDescriptor::PlatformHandleType;
+
+using namespace mozilla::ipc;
+using namespace mozilla::net;
+
+using mozilla::DebugOnly;
+using mozilla::Maybe;
+using mozilla::Nothing;
+using mozilla::Some;
+
+////////////////////////////////////////////////////////////////////////////////
+// nsFileStreamBase
+
+nsFileStreamBase::~nsFileStreamBase() {
+  // We don't want to try to rewrind the stream when shutting down.
+  mBehaviorFlags &= ~nsIFileInputStream::REOPEN_ON_REWIND;
+
+  Close();
+}
+
+NS_IMPL_ISUPPORTS(nsFileStreamBase, nsISeekableStream, nsITellableStream,
+                  nsIFileMetadata)
+
+NS_IMETHODIMP
+nsFileStreamBase::Seek(int32_t whence, int64_t offset) {
+  nsresult rv = DoPendingOpen();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  int64_t cnt = PR_Seek64(mFD, offset, (PRSeekWhence)whence);
+  if (cnt == int64_t(-1)) {
+    return NS_ErrorAccordingToNSPR();
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFileStreamBase::Tell(int64_t* result) {
+  if (mState == eDeferredOpen && !(mOpenParams.ioFlags & PR_APPEND)) {
+    *result = 0;
+    return NS_OK;
+  }
+
+  nsresult rv = DoPendingOpen();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  int64_t cnt = PR_Seek64(mFD, 0, PR_SEEK_CUR);
+  if (cnt == int64_t(-1)) {
+    return NS_ErrorAccordingToNSPR();
+  }
+  *result = cnt;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFileStreamBase::SetEOF() {
+  nsresult rv = DoPendingOpen();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+#if defined(XP_UNIX)
+  // Some system calls require an EOF offset.
+  int64_t offset;
+  rv = Tell(&offset);
+  if (NS_FAILED(rv)) return rv;
+#endif
+
+#if defined(XP_UNIX)
+  if (ftruncate(PR_FileDesc2NativeHandle(mFD), offset) != 0) {
+    NS_ERROR("ftruncate failed");
+    return NS_ERROR_FAILURE;
+  }
+#elif defined(XP_WIN)
+  if (!SetEndOfFile((HANDLE)PR_FileDesc2NativeHandle(mFD))) {
+    NS_ERROR("SetEndOfFile failed");
+    return NS_ERROR_FAILURE;
+  }
+#else
+  // XXX not implemented
+#endif
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFileStreamBase::GetSize(int64_t* _retval) {
+  nsresult rv = DoPendingOpen();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  PRFileInfo64 info;
+  if (PR_GetOpenFileInfo64(mFD, &info) == PR_FAILURE) {
+    return NS_BASE_STREAM_OSERROR;
+  }
+
+  *_retval = int64_t(info.size);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFileStreamBase::GetLastModified(int64_t* _retval) {
+  nsresult rv = DoPendingOpen();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  PRFileInfo64 info;
+  if (PR_GetOpenFileInfo64(mFD, &info) == PR_FAILURE) {
+    return NS_BASE_STREAM_OSERROR;
+  }
+
+  int64_t modTime = int64_t(info.modifyTime);
+  if (modTime == 0) {
+    *_retval = 0;
+  } else {
+    *_retval = modTime / int64_t(PR_USEC_PER_MSEC);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFileStreamBase::GetFileDescriptor(PRFileDesc** _retval) {
+  nsresult rv = DoPendingOpen();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  *_retval = mFD;
+  return NS_OK;
+}
+
+nsresult nsFileStreamBase::Close() {
+  CleanUpOpen();
+
+  nsresult rv = NS_OK;
+  if (mFD) {
+    if (PR_Close(mFD) == PR_FAILURE) rv = NS_BASE_STREAM_OSERROR;
+    mFD = nullptr;
+    mState = eClosed;
+  }
+  return rv;
+}
+
+nsresult nsFileStreamBase::Available(uint64_t* aResult) {
+  nsresult rv = DoPendingOpen();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // PR_Available with files over 4GB returns an error, so we have to
+  // use the 64-bit version of PR_Available.
+  int64_t avail = PR_Available64(mFD);
+  if (avail == -1) {
+    return NS_ErrorAccordingToNSPR();
+  }
+
+  // If available is greater than 4GB, return 4GB
+  *aResult = (uint64_t)avail;
+  return NS_OK;
+}
+
+nsresult nsFileStreamBase::Read(char* aBuf, uint32_t aCount,
+                                uint32_t* aResult) {
+  nsresult rv = DoPendingOpen();
+  if (rv == NS_BASE_STREAM_CLOSED) {
+    *aResult = 0;
+    return NS_OK;
+  }
+
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  int32_t bytesRead = PR_Read(mFD, aBuf, aCount);
+  if (bytesRead == -1) {
+    return NS_ErrorAccordingToNSPR();
+  }
+
+  *aResult = bytesRead;
+  return NS_OK;
+}
+
+nsresult nsFileStreamBase::ReadSegments(nsWriteSegmentFun aWriter,
+                                        void* aClosure, uint32_t aCount,
+                                        uint32_t* aResult) {
+  // ReadSegments is not implemented because it would be inefficient when
+  // the writer does not consume all data.  If you want to call ReadSegments,
+  // wrap a BufferedInputStream around the file stream.  That will call
+  // Read().
+
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+nsresult nsFileStreamBase::IsNonBlocking(bool* aNonBlocking) {
+  *aNonBlocking = false;
+  return NS_OK;
+}
+
+nsresult nsFileStreamBase::Flush(void) {
+  nsresult rv = DoPendingOpen();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  int32_t cnt = PR_Sync(mFD);
+  if (cnt == -1) {
+    return NS_ErrorAccordingToNSPR();
+  }
+  return NS_OK;
+}
+
+nsresult nsFileStreamBase::Write(const char* buf, uint32_t count,
+                                 uint32_t* result) {
+  nsresult rv = DoPendingOpen();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  int32_t cnt = PR_Write(mFD, buf, count);
+  if (cnt == -1) {
+    return NS_ErrorAccordingToNSPR();
+  }
+  *result = cnt;
+  return NS_OK;
+}
+
+nsresult nsFileStreamBase::WriteFrom(nsIInputStream* inStr, uint32_t count,
+                                     uint32_t* _retval) {
+  MOZ_ASSERT_UNREACHABLE("WriteFrom (see source comment)");
+  return NS_ERROR_NOT_IMPLEMENTED;
+  // File streams intentionally do not support this method.
+  // If you need something like this, then you should wrap
+  // the file stream using nsIBufferedOutputStream
+}
+
+nsresult nsFileStreamBase::WriteSegments(nsReadSegmentFun reader, void* closure,
+                                         uint32_t count, uint32_t* _retval) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+  // File streams intentionally do not support this method.
+  // If you need something like this, then you should wrap
+  // the file stream using nsIBufferedOutputStream
+}
+
+nsresult nsFileStreamBase::MaybeOpen(nsIFile* aFile, int32_t aIoFlags,
+                                     int32_t aPerm, bool aDeferred) {
+  NS_ENSURE_STATE(aFile);
+
+  mOpenParams.ioFlags = aIoFlags;
+  mOpenParams.perm = aPerm;
+
+  if (aDeferred) {
+    // Clone the file, as it may change between now and the deferred open
+    nsCOMPtr<nsIFile> file;
+    nsresult rv = aFile->Clone(getter_AddRefs(file));
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    mOpenParams.localFile = std::move(file);
+    NS_ENSURE_TRUE(mOpenParams.localFile, NS_ERROR_UNEXPECTED);
+
+    mState = eDeferredOpen;
+    return NS_OK;
+  }
+
+  mOpenParams.localFile = aFile;
+
+  // Following call open() at main thread.
+  // Main thread might be blocked, while open a remote file.
+  return DoOpen();
+}
+
+void nsFileStreamBase::CleanUpOpen() { mOpenParams.localFile = nullptr; }
+
+nsresult nsFileStreamBase::DoOpen() {
+  MOZ_ASSERT(mState == eDeferredOpen || mState == eUnitialized ||
+             mState == eClosed);
+  NS_ASSERTION(!mFD, "Already have a file descriptor!");
+  NS_ASSERTION(mOpenParams.localFile, "Must have a file to open");
+
+  PRFileDesc* fd;
+  nsresult rv;
+
+  if (mOpenParams.ioFlags & PR_CREATE_FILE) {
+    nsCOMPtr<nsIFile> parent;
+    mOpenParams.localFile->GetParent(getter_AddRefs(parent));
+
+    // Result doesn't need to be checked. If the file's parent path does not
+    // exist, make it. If it does exist, do nothing.
+    if (parent) {
+      Unused << parent->Create(nsIFile::DIRECTORY_TYPE, 0755);
+    }
+  }
+
+#ifdef XP_WIN
+  if (mBehaviorFlags & nsIFileInputStream::SHARE_DELETE) {
+    nsCOMPtr<nsILocalFileWin> file = do_QueryInterface(mOpenParams.localFile);
+    MOZ_ASSERT(file);
+
+    rv = file->OpenNSPRFileDescShareDelete(mOpenParams.ioFlags,
+                                           mOpenParams.perm, &fd);
+  } else
+#endif  // XP_WIN
+  {
+    rv = mOpenParams.localFile->OpenNSPRFileDesc(mOpenParams.ioFlags,
+                                                 mOpenParams.perm, &fd);
+  }
+
+  if (rv == NS_OK && IOActivityMonitor::IsActive()) {
+    auto nativePath = mOpenParams.localFile->NativePath();
+    if (!nativePath.IsEmpty()) {
+// registering the file to the activity monitor
+#ifdef XP_WIN
+      // 16 bits unicode
+      IOActivityMonitor::MonitorFile(
+          fd, NS_ConvertUTF16toUTF8(nativePath.get()).get());
+#else
+      // 8 bit unicode
+      IOActivityMonitor::MonitorFile(fd, nativePath.get());
+#endif
+    }
+  }
+
+  CleanUpOpen();
+
+  if (NS_FAILED(rv)) {
+    mState = eError;
+    mErrorValue = rv;
+    return rv;
+  }
+
+  mFD = fd;
+  mState = eOpened;
+
+  return NS_OK;
+}
+
+nsresult nsFileStreamBase::DoPendingOpen() {
+  switch (mState) {
+    case eUnitialized:
+      MOZ_CRASH("This should not happen.");
+      return NS_ERROR_FAILURE;
+
+    case eDeferredOpen:
+      return DoOpen();
+
+    case eOpened:
+      MOZ_ASSERT(mFD);
+      if (NS_WARN_IF(!mFD)) {
+        return NS_ERROR_FAILURE;
+      }
+      return NS_OK;
+
+    case eClosed:
+      MOZ_ASSERT(!mFD);
+      return NS_BASE_STREAM_CLOSED;
+
+    case eError:
+      return mErrorValue;
+  }
+
+  MOZ_CRASH("Invalid mState value.");
+  return NS_ERROR_FAILURE;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// nsFileInputStream
+
+NS_IMPL_ADDREF_INHERITED(nsFileInputStream, nsFileStreamBase)
+NS_IMPL_RELEASE_INHERITED(nsFileInputStream, nsFileStreamBase)
+
+NS_IMPL_CLASSINFO(nsFileInputStream, nullptr, nsIClassInfo::THREADSAFE,
+                  NS_LOCALFILEINPUTSTREAM_CID)
+
+NS_INTERFACE_MAP_BEGIN(nsFileInputStream)
+  NS_INTERFACE_MAP_ENTRY(nsIInputStream)
+  NS_INTERFACE_MAP_ENTRY(nsIFileInputStream)
+  NS_INTERFACE_MAP_ENTRY(nsILineInputStream)
+  NS_INTERFACE_MAP_ENTRY(nsIIPCSerializableInputStream)
+  NS_IMPL_QUERY_CLASSINFO(nsFileInputStream)
+  NS_INTERFACE_MAP_ENTRY_CONDITIONAL(nsICloneableInputStream, IsCloneable())
+NS_INTERFACE_MAP_END_INHERITING(nsFileStreamBase)
+
+NS_IMPL_CI_INTERFACE_GETTER(nsFileInputStream, nsIInputStream,
+                            nsIFileInputStream, nsISeekableStream,
+                            nsITellableStream, nsILineInputStream)
+
+nsresult nsFileInputStream::Create(REFNSIID aIID, void** aResult) {
+  RefPtr<nsFileInputStream> stream = new nsFileInputStream();
+  return stream->QueryInterface(aIID, aResult);
+}
+
+nsresult nsFileInputStream::Open(nsIFile* aFile, int32_t aIOFlags,
+                                 int32_t aPerm) {
+  nsresult rv = NS_OK;
+
+  // If the previous file is open, close it
+  if (mFD) {
+    rv = Close();
+    if (NS_FAILED(rv)) return rv;
+  }
+
+  // Open the file
+  if (aIOFlags == -1) aIOFlags = PR_RDONLY;
+  if (aPerm == -1) aPerm = 0;
+
+  return MaybeOpen(aFile, aIOFlags, aPerm,
+                   mBehaviorFlags & nsIFileInputStream::DEFER_OPEN);
+}
+
+NS_IMETHODIMP
+nsFileInputStream::Init(nsIFile* aFile, int32_t aIOFlags, int32_t aPerm,
+                        int32_t aBehaviorFlags) {
+  NS_ENSURE_TRUE(!mFD, NS_ERROR_ALREADY_INITIALIZED);
+  NS_ENSURE_TRUE(mState == eUnitialized || mState == eClosed,
+                 NS_ERROR_ALREADY_INITIALIZED);
+
+  mBehaviorFlags = aBehaviorFlags;
+  mState = eUnitialized;
+
+  mFile = aFile;
+  mIOFlags = aIOFlags;
+  mPerm = aPerm;
+
+  return Open(aFile, aIOFlags, aPerm);
+}
+
+NS_IMETHODIMP
+nsFileInputStream::Close() {
+  // Get the cache position at the time the file was close. This allows
+  // NS_SEEK_CUR on a closed file that has been opened with
+  // REOPEN_ON_REWIND.
+  if (mBehaviorFlags & REOPEN_ON_REWIND) {
+    // Get actual position. Not one modified by subclasses
+    nsFileStreamBase::Tell(&mCachedPosition);
+  }
+
+  // null out mLineBuffer in case Close() is called again after failing
+  mLineBuffer = nullptr;
+  return nsFileStreamBase::Close();
+}
+
+NS_IMETHODIMP
+nsFileInputStream::Read(char* aBuf, uint32_t aCount, uint32_t* _retval) {
+  nsresult rv = nsFileStreamBase::Read(aBuf, aCount, _retval);
+  if (rv == NS_ERROR_FILE_NOT_FOUND) {
+    // Don't warn if this is a deffered file not found.
+    return rv;
+  }
+
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Check if we're at the end of file and need to close
+  if (mBehaviorFlags & CLOSE_ON_EOF && *_retval == 0) {
+    Close();
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFileInputStream::ReadLine(nsACString& aLine, bool* aResult) {
+  if (!mLineBuffer) {
+    mLineBuffer = MakeUnique<nsLineBuffer<char>>();
+  }
+  return NS_ReadLine(this, mLineBuffer.get(), aLine, aResult);
+}
+
+NS_IMETHODIMP
+nsFileInputStream::Seek(int32_t aWhence, int64_t aOffset) {
+  return SeekInternal(aWhence, aOffset);
+}
+
+nsresult nsFileInputStream::SeekInternal(int32_t aWhence, int64_t aOffset,
+                                         bool aClearBuf) {
+  nsresult rv = DoPendingOpen();
+  if (rv != NS_OK && rv != NS_BASE_STREAM_CLOSED) {
+    return rv;
+  }
+
+  if (aClearBuf) {
+    mLineBuffer = nullptr;
+  }
+
+  if (rv == NS_BASE_STREAM_CLOSED) {
+    if (mBehaviorFlags & REOPEN_ON_REWIND) {
+      rv = Open(mFile, mIOFlags, mPerm);
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      // If the file was closed, and we do a relative seek, use the
+      // position we cached when we closed the file to seek to the right
+      // location.
+      if (aWhence == NS_SEEK_CUR) {
+        aWhence = NS_SEEK_SET;
+        aOffset += mCachedPosition;
+      }
+      // If we're trying to seek to the start then we're done, so
+      // return early to avoid Seek from calling DoPendingOpen and
+      // opening the underlying file earlier than necessary.
+      if (aWhence == NS_SEEK_SET && aOffset == 0) {
+        return NS_OK;
+      }
+    } else {
+      return NS_BASE_STREAM_CLOSED;
+    }
+  }
+
+  return nsFileStreamBase::Seek(aWhence, aOffset);
+}
+
+NS_IMETHODIMP
+nsFileInputStream::Tell(int64_t* aResult) {
+  return nsFileStreamBase::Tell(aResult);
+}
+
+NS_IMETHODIMP
+nsFileInputStream::Available(uint64_t* aResult) {
+  return nsFileStreamBase::Available(aResult);
+}
+
+void nsFileInputStream::SerializedComplexity(uint32_t aMaxSize,
+                                             uint32_t* aSizeUsed,
+                                             uint32_t* aPipes,
+                                             uint32_t* aTransferables) {
+  *aTransferables = 1;
+}
+
+void nsFileInputStream::Serialize(InputStreamParams& aParams, uint32_t aMaxSize,
+                                  uint32_t* aSizeUsed) {
+  MOZ_ASSERT(aSizeUsed);
+  *aSizeUsed = 0;
+
+  FileInputStreamParams params;
+
+  if (NS_SUCCEEDED(DoPendingOpen())) {
+    MOZ_ASSERT(mFD);
+    FileHandleType fd = FileHandleType(PR_FileDesc2NativeHandle(mFD));
+    NS_ASSERTION(fd, "This should never be null!");
+
+    params.fileDescriptor() = FileDescriptor(fd);
+
+    Close();
+  } else {
+    NS_WARNING(
+        "This file has not been opened (or could not be opened). "
+        "Sending an invalid file descriptor to the other process!");
+
+    params.fileDescriptor() = FileDescriptor();
+  }
+
+  int32_t behaviorFlags = mBehaviorFlags;
+
+  // The receiving process (or thread) is going to have an open file
+  // descriptor automatically so transferring this flag is meaningless.
+  behaviorFlags &= ~nsIFileInputStream::DEFER_OPEN;
+
+  params.behaviorFlags() = behaviorFlags;
+  params.ioFlags() = mIOFlags;
+
+  aParams = params;
+}
+
+bool nsFileInputStream::Deserialize(const InputStreamParams& aParams) {
+  NS_ASSERTION(!mFD, "Already have a file descriptor?!");
+  NS_ASSERTION(mState == nsFileStreamBase::eUnitialized, "Deferring open?!");
+  NS_ASSERTION(!mFile, "Should never have a file here!");
+  NS_ASSERTION(!mPerm, "This should always be 0!");
+
+  if (aParams.type() != InputStreamParams::TFileInputStreamParams) {
+    NS_WARNING("Received unknown parameters from the other process!");
+    return false;
+  }
+
+  const FileInputStreamParams& params = aParams.get_FileInputStreamParams();
+
+  const FileDescriptor& fd = params.fileDescriptor();
+
+  if (fd.IsValid()) {
+    auto rawFD = fd.ClonePlatformHandle();
+    PRFileDesc* fileDesc = PR_ImportFile(PROsfd(rawFD.release()));
+    if (!fileDesc) {
+      NS_WARNING("Failed to import file handle!");
+      return false;
+    }
+    mFD = fileDesc;
+    mState = eOpened;
+  } else {
+    NS_WARNING("Received an invalid file descriptor!");
+    mState = eError;
+    mErrorValue = NS_ERROR_FILE_NOT_FOUND;
+  }
+
+  mBehaviorFlags = params.behaviorFlags();
+
+  if (!XRE_IsParentProcess()) {
+    // A child process shouldn't close when it reads the end because it will
+    // not be able to reopen the file later.
+    mBehaviorFlags &= ~nsIFileInputStream::CLOSE_ON_EOF;
+
+    // A child process will not be able to reopen the file so this flag is
+    // meaningless.
+    mBehaviorFlags &= ~nsIFileInputStream::REOPEN_ON_REWIND;
+  }
+
+  mIOFlags = params.ioFlags();
+
+  return true;
+}
+
+bool nsFileInputStream::IsCloneable() const {
+  // This inputStream is cloneable only if has been created using Init() and
+  // it owns a nsIFile. This is not true when it is deserialized from IPC.
+  return XRE_IsParentProcess() && mFile;
+}
+
+NS_IMETHODIMP
+nsFileInputStream::GetCloneable(bool* aCloneable) {
+  *aCloneable = IsCloneable();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFileInputStream::Clone(nsIInputStream** aResult) {
+  MOZ_ASSERT(IsCloneable());
+  return NS_NewLocalFileInputStream(aResult, mFile, mIOFlags, mPerm,
+                                    mBehaviorFlags);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// nsFileOutputStream
+
+NS_IMPL_ISUPPORTS_INHERITED(nsFileOutputStream, nsFileStreamBase,
+                            nsIOutputStream, nsIFileOutputStream)
+
+nsresult nsFileOutputStream::Create(REFNSIID aIID, void** aResult) {
+  RefPtr<nsFileOutputStream> stream = new nsFileOutputStream();
+  return stream->QueryInterface(aIID, aResult);
+}
+
+NS_IMETHODIMP
+nsFileOutputStream::Init(nsIFile* file, int32_t ioFlags, int32_t perm,
+                         int32_t behaviorFlags) {
+  NS_ENSURE_TRUE(mFD == nullptr, NS_ERROR_ALREADY_INITIALIZED);
+  NS_ENSURE_TRUE(mState == eUnitialized || mState == eClosed,
+                 NS_ERROR_ALREADY_INITIALIZED);
+
+  mBehaviorFlags = behaviorFlags;
+  mState = eUnitialized;
+
+  if (ioFlags == -1) ioFlags = PR_WRONLY | PR_CREATE_FILE | PR_TRUNCATE;
+  if (perm <= 0) perm = 0664;
+
+  return MaybeOpen(file, ioFlags, perm,
+                   mBehaviorFlags & nsIFileOutputStream::DEFER_OPEN);
+}
+
+nsresult nsFileOutputStream::InitWithFileDescriptor(
+    const mozilla::ipc::FileDescriptor& aFd) {
+  NS_ENSURE_TRUE(mFD == nullptr, NS_ERROR_ALREADY_INITIALIZED);
+  NS_ENSURE_TRUE(mState == eUnitialized || mState == eClosed,
+                 NS_ERROR_ALREADY_INITIALIZED);
+
+  if (aFd.IsValid()) {
+    auto rawFD = aFd.ClonePlatformHandle();
+    PRFileDesc* fileDesc = PR_ImportFile(PROsfd(rawFD.release()));
+    if (!fileDesc) {
+      NS_WARNING("Failed to import file handle!");
+      return NS_ERROR_FAILURE;
+    }
+    mFD = fileDesc;
+    mState = eOpened;
+  } else {
+    mState = eError;
+    mErrorValue = NS_ERROR_FILE_NOT_FOUND;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFileOutputStream::Preallocate(int64_t aLength) {
+  if (!mFD) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  if (!mozilla::fallocate(mFD, aLength)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// nsAtomicFileOutputStream
+
+NS_IMPL_ISUPPORTS_INHERITED(nsAtomicFileOutputStream, nsFileOutputStream,
+                            nsISafeOutputStream, nsIOutputStream,
+                            nsIFileOutputStream)
+
+NS_IMETHODIMP
+nsAtomicFileOutputStream::Init(nsIFile* file, int32_t ioFlags, int32_t perm,
+                               int32_t behaviorFlags) {
+  // While `PR_APPEND` is not supported, `-1` is used as `ioFlags` parameter
+  // in some places, and `PR_APPEND | PR_TRUNCATE` does not require appending
+  // to existing file. So, throw an exception only if `PR_APPEND` is
+  // explicitly specified without `PR_TRUNCATE`.
+  if ((ioFlags & PR_APPEND) && !(ioFlags & PR_TRUNCATE)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+  return nsFileOutputStream::Init(file, ioFlags, perm, behaviorFlags);
+}
+
+nsresult nsAtomicFileOutputStream::DoOpen() {
+  // Make sure mOpenParams.localFile will be empty if we bail somewhere in
+  // this function
+  nsCOMPtr<nsIFile> file;
+  file.swap(mOpenParams.localFile);
+
+  if (!file) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  nsresult rv = file->Exists(&mTargetFileExists);
+  if (NS_FAILED(rv)) {
+    NS_ERROR("Can't tell if target file exists");
+    mTargetFileExists =
+        true;  // Safer to assume it exists - we just do more work.
+  }
+
+  // follow symlinks, for two reasons:
+  // 1) if a user has deliberately set up a profile file as a symlink, we
+  //    honor it
+  // 2) to make the MoveToNative() in Finish() an atomic operation (which may
+  //    not be the case if moving across directories on different
+  //    filesystems).
+  nsCOMPtr<nsIFile> tempResult;
+  rv = file->Clone(getter_AddRefs(tempResult));
+  if (NS_SUCCEEDED(rv) && mTargetFileExists) {
+    tempResult->Normalize();
+  }
+
+  if (NS_SUCCEEDED(rv) && mTargetFileExists) {
+    // Abort if |file| is not writable; it won't work as an output stream.
+    bool isWritable;
+    if (NS_SUCCEEDED(file->IsWritable(&isWritable)) && !isWritable) {
+      return NS_ERROR_FILE_ACCESS_DENIED;
+    }
+
+    uint32_t origPerm;
+    if (NS_FAILED(file->GetPermissions(&origPerm))) {
+      NS_ERROR("Can't get permissions of target file");
+      origPerm = mOpenParams.perm;
+    }
+
+    // XXX What if |perm| is more restrictive then |origPerm|?
+    // This leaves the user supplied permissions as they were.
+    rv = tempResult->CreateUnique(nsIFile::NORMAL_FILE_TYPE, origPerm);
+  }
+  if (NS_SUCCEEDED(rv)) {
+    // nsFileOutputStream::DoOpen will work on the temporary file, so we
+    // prepare it and place it in mOpenParams.localFile.
+    mOpenParams.localFile = tempResult;
+    mTempFile = tempResult;
+    mTargetFile = file;
+    rv = nsFileOutputStream::DoOpen();
+  }
+  return rv;
+}
+
+NS_IMETHODIMP
+nsAtomicFileOutputStream::Close() {
+  nsresult rv = nsFileOutputStream::Close();
+
+  // the consumer doesn't want the original file overwritten -
+  // so clean up by removing the temp file.
+  if (mTempFile) {
+    mTempFile->Remove(false);
+    mTempFile = nullptr;
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP
+nsAtomicFileOutputStream::Finish() {
+  nsresult rv = nsFileOutputStream::Close();
+
+  // if there is no temp file, don't try to move it over the original target.
+  // It would destroy the targetfile if close() is called twice.
+  if (!mTempFile) return rv;
+
+  // Only overwrite if everything was ok, and the temp file could be closed.
+  if (NS_SUCCEEDED(mWriteResult) && NS_SUCCEEDED(rv)) {
+    NS_ENSURE_STATE(mTargetFile);
+
+    if (!mTargetFileExists) {
+      // If the target file did not exist when we were initialized, then the
+      // temp file we gave out was actually a reference to the target file.
+      // since we succeeded in writing to the temp file (and hence succeeded
+      // in writing to the target file), there is nothing more to do.
+#ifdef DEBUG
+      bool equal;
+      if (NS_FAILED(mTargetFile->Equals(mTempFile, &equal)) || !equal) {
+        NS_WARNING("mTempFile not equal to mTargetFile");
+      }
+#endif
+    } else {
+      nsAutoString targetFilename;
+      rv = mTargetFile->GetLeafName(targetFilename);
+      if (NS_SUCCEEDED(rv)) {
+        // This will replace target.
+        rv = mTempFile->MoveTo(nullptr, targetFilename);
+        if (NS_FAILED(rv)) mTempFile->Remove(false);
+      }
+    }
+  } else {
+    mTempFile->Remove(false);
+
+    // if writing failed, propagate the failure code to the caller.
+    if (NS_FAILED(mWriteResult)) rv = mWriteResult;
+  }
+  mTempFile = nullptr;
+  return rv;
+}
+
+NS_IMETHODIMP
+nsAtomicFileOutputStream::Write(const char* buf, uint32_t count,
+                                uint32_t* result) {
+  nsresult rv = nsFileOutputStream::Write(buf, count, result);
+  if (NS_SUCCEEDED(mWriteResult)) {
+    if (NS_FAILED(rv)) {
+      mWriteResult = rv;
+    } else if (count != *result) {
+      mWriteResult = NS_ERROR_LOSS_OF_SIGNIFICANT_DATA;
+    }
+
+    if (NS_FAILED(mWriteResult) && count > 0) {
+      NS_WARNING("writing to output stream failed! data may be lost");
+    }
+  }
+  return rv;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// nsSafeFileOutputStream
+
+NS_IMETHODIMP
+nsSafeFileOutputStream::Finish() {
+  (void)Flush();
+  return nsAtomicFileOutputStream::Finish();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// nsFileRandomAccessStream
+
+nsresult nsFileRandomAccessStream::Create(REFNSIID aIID, void** aResult) {
+  RefPtr<nsFileRandomAccessStream> stream = new nsFileRandomAccessStream();
+  return stream->QueryInterface(aIID, aResult);
+}
+
+NS_IMPL_ISUPPORTS_INHERITED(nsFileRandomAccessStream, nsFileStreamBase,
+                            nsIRandomAccessStream, nsIFileRandomAccessStream,
+                            nsIInputStream, nsIOutputStream)
+
+NS_IMETHODIMP
+nsFileRandomAccessStream::GetInputStream(nsIInputStream** aInputStream) {
+  nsCOMPtr<nsIInputStream> inputStream(this);
+
+  inputStream.forget(aInputStream);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFileRandomAccessStream::GetOutputStream(nsIOutputStream** aOutputStream) {
+  nsCOMPtr<nsIOutputStream> outputStream(this);
+
+  outputStream.forget(aOutputStream);
+  return NS_OK;
+}
+
+nsIInputStream* nsFileRandomAccessStream::InputStream() { return this; }
+
+nsIOutputStream* nsFileRandomAccessStream::OutputStream() { return this; }
+
+RandomAccessStreamParams nsFileRandomAccessStream::Serialize(
+    nsIInterfaceRequestor* aCallbacks) {
+  FileRandomAccessStreamParams params;
+
+  if (NS_SUCCEEDED(DoPendingOpen())) {
+    MOZ_ASSERT(mFD);
+    FileHandleType fd = FileHandleType(PR_FileDesc2NativeHandle(mFD));
+    MOZ_ASSERT(fd, "This should never be null!");
+
+    params.fileDescriptor() = FileDescriptor(fd);
+
+    Close();
+  } else {
+    NS_WARNING(
+        "This file has not been opened (or could not be opened). "
+        "Sending an invalid file descriptor to the other process!");
+
+    params.fileDescriptor() = FileDescriptor();
+  }
+
+  int32_t behaviorFlags = mBehaviorFlags;
+
+  // The receiving process (or thread) is going to have an open file
+  // descriptor automatically so transferring this flag is meaningless.
+  behaviorFlags &= ~nsIFileInputStream::DEFER_OPEN;
+
+  params.behaviorFlags() = behaviorFlags;
+
+  return params;
+}
+
+bool nsFileRandomAccessStream::Deserialize(
+    RandomAccessStreamParams& aStreamParams) {
+  MOZ_ASSERT(!mFD, "Already have a file descriptor?!");
+  MOZ_ASSERT(mState == nsFileStreamBase::eUnitialized, "Deferring open?!");
+
+  if (aStreamParams.type() !=
+      RandomAccessStreamParams::TFileRandomAccessStreamParams) {
+    NS_WARNING("Received unknown parameters from the other process!");
+    return false;
+  }
+
+  const FileRandomAccessStreamParams& params =
+      aStreamParams.get_FileRandomAccessStreamParams();
+
+  const FileDescriptor& fd = params.fileDescriptor();
+
+  if (fd.IsValid()) {
+    auto rawFD = fd.ClonePlatformHandle();
+    PRFileDesc* fileDesc = PR_ImportFile(PROsfd(rawFD.release()));
+    if (!fileDesc) {
+      NS_WARNING("Failed to import file handle!");
+      return false;
+    }
+    mFD = fileDesc;
+    mState = eOpened;
+  } else {
+    NS_WARNING("Received an invalid file descriptor!");
+    mState = eError;
+    mErrorValue = NS_ERROR_FILE_NOT_FOUND;
+  }
+
+  mBehaviorFlags = params.behaviorFlags();
+
+  return true;
+}
+
+NS_IMETHODIMP
+nsFileRandomAccessStream::Init(nsIFile* file, int32_t ioFlags, int32_t perm,
+                               int32_t behaviorFlags) {
+  NS_ENSURE_TRUE(mFD == nullptr, NS_ERROR_ALREADY_INITIALIZED);
+  NS_ENSURE_TRUE(mState == eUnitialized || mState == eClosed,
+                 NS_ERROR_ALREADY_INITIALIZED);
+
+  mBehaviorFlags = behaviorFlags;
+  mState = eUnitialized;
+
+  if (ioFlags == -1) ioFlags = PR_RDWR;
+  if (perm <= 0) perm = 0;
+
+  return MaybeOpen(file, ioFlags, perm,
+                   mBehaviorFlags & nsIFileRandomAccessStream::DEFER_OPEN);
+}
+
+////////////////////////////////////////////////////////////////////////////////