Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

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

38 files changed, 11598 insertions, 0 deletions

diff --git a/comm/mailnews/db/msgdb/.eslintrc.js b/comm/mailnews/db/msgdb/.eslintrc.js
new file mode 100644
index 0000000000..5816519fbb
--- /dev/null
+++ b/comm/mailnews/db/msgdb/.eslintrc.js
@@ -0,0 +1,5 @@
+"use strict";
+
+module.exports = {
+  extends: ["plugin:mozilla/valid-jsdoc"],
+};
diff --git a/comm/mailnews/db/msgdb/moz.build b/comm/mailnews/db/msgdb/moz.build
new file mode 100644
index 0000000000..a49689ab64
--- /dev/null
+++ b/comm/mailnews/db/msgdb/moz.build
@@ -0,0 +1,11 @@
+# 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/.
+
+DIRS += [
+    "public",
+    "src",
+]
+
+TEST_DIRS += ["test"]
diff --git a/comm/mailnews/db/msgdb/public/moz.build b/comm/mailnews/db/msgdb/public/moz.build
new file mode 100644
index 0000000000..5bed71ce9c
--- /dev/null
+++ b/comm/mailnews/db/msgdb/public/moz.build
@@ -0,0 +1,25 @@
+# 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/.
+
+XPIDL_SOURCES += [
+    "nsIDBChangeAnnouncer.idl",
+    "nsIDBChangeListener.idl",
+    "nsIDBFolderInfo.idl",
+    "nsIMsgDatabase.idl",
+    "nsIMsgOfflineImapOperation.idl",
+    "nsINewsDatabase.idl",
+]
+
+XPIDL_MODULE = "msgdb"
+
+EXPORTS += [
+    "nsDBFolderInfo.h",
+    "nsImapMailDatabase.h",
+    "nsMailDatabase.h",
+    "nsMsgDatabase.h",
+    "nsMsgHdr.h",
+    "nsMsgThread.h",
+    "nsNewsDatabase.h",
+]
diff --git a/comm/mailnews/db/msgdb/public/nsDBFolderInfo.h b/comm/mailnews/db/msgdb/public/nsDBFolderInfo.h
new file mode 100644
index 0000000000..5b1150e4e7
--- /dev/null
+++ b/comm/mailnews/db/msgdb/public/nsDBFolderInfo.h
@@ -0,0 +1,151 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 class encapsulates the global information about a folder stored in the
+   summary file.
+*/
+#ifndef _nsDBFolderInfo_H
+#define _nsDBFolderInfo_H
+
+#include "mozilla/MemoryReporting.h"
+#include "nsString.h"
+#include "MailNewsTypes.h"
+#include "mdb.h"
+#include "nsTArray.h"
+#include "nsIDBFolderInfo.h"
+#include <time.h>
+
+class nsMsgDatabase;
+
+// again, this could inherit from nsISupports, but I don't see the need as of
+// yet. I'm not sure it needs to be ref-counted (but I think it does).
+
+// I think these getters and setters really need to go through mdb and not rely
+// on the object caching the values. If this somehow turns out to be
+// prohibitively expensive, we can invent some sort of dirty mechanism, but I
+// think it turns out that these values will be cached by the MSG_FolderInfo's
+// anyway.
+class nsDBFolderInfo : public nsIDBFolderInfo {
+ public:
+  friend class nsMsgDatabase;
+
+  explicit nsDBFolderInfo(nsMsgDatabase* mdb);
+
+  NS_DECL_ISUPPORTS
+  // interface methods.
+  NS_DECL_NSIDBFOLDERINFO
+  // create the appropriate table and row in a new db.
+  nsresult AddToNewMDB();
+  // accessor methods.
+
+  bool TestFlag(int32_t flags);
+  int16_t GetIMAPHierarchySeparator();
+  void SetIMAPHierarchySeparator(int16_t hierarchyDelimiter);
+  void ChangeImapTotalPendingMessages(int32_t delta);
+  void ChangeImapUnreadPendingMessages(int32_t delta);
+
+  nsresult InitFromExistingDB();
+  // get and set arbitrary property, aka row cell value.
+  nsresult SetPropertyWithToken(mdb_token aProperty,
+                                const nsAString& propertyStr);
+  nsresult SetUint32PropertyWithToken(mdb_token aProperty,
+                                      uint32_t propertyValue);
+  nsresult SetInt64PropertyWithToken(mdb_token aProperty,
+                                     int64_t propertyValue);
+  nsresult SetInt32PropertyWithToken(mdb_token aProperty,
+                                     int32_t propertyValue);
+  nsresult GetPropertyWithToken(mdb_token aProperty, nsAString& propertyValue);
+  nsresult GetUint32PropertyWithToken(mdb_token aProperty,
+                                      uint32_t& propertyValue,
+                                      uint32_t defaultValue = 0);
+  nsresult GetInt32PropertyWithToken(mdb_token aProperty,
+                                     int32_t& propertyValue,
+                                     int32_t defaultValue = 0);
+  nsresult GetInt64PropertyWithToken(mdb_token aProperty,
+                                     int64_t& propertyValue,
+                                     int64_t defaultValue = 0);
+
+  nsTArray<nsMsgKey> m_lateredKeys;  // list of latered messages
+
+  virtual size_t SizeOfExcludingThis(
+      mozilla::MallocSizeOf aMallocSizeOf) const {
+    return m_lateredKeys.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  }
+  virtual size_t SizeOfIncludingThis(
+      mozilla::MallocSizeOf aMallocSizeOf) const {
+    return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+  }
+
+ protected:
+  virtual ~nsDBFolderInfo();
+
+  // initialize from appropriate table and row in existing db.
+  nsresult InitMDBInfo();
+  nsresult LoadMemberVariables();
+
+  nsresult AdjustHighWater(nsMsgKey highWater, bool force);
+
+  void
+  ReleaseExternalReferences();  // let go of any references to other objects.
+
+  int64_t m_folderSize;
+  int64_t m_expungedBytes;  // sum of size of deleted messages in folder
+  uint32_t m_folderDate;
+  nsMsgKey m_highWaterMessageKey;  // largest news article number or imap uid
+                                   // whose header we've seen
+
+  //  m_numUnreadMessages and m_numMessages can never be negative. 0 means 'no
+  //  msgs'.
+  int32_t m_numUnreadMessages;
+  int32_t m_numMessages;  // includes expunged and ignored messages
+
+  int32_t m_flags;  // folder specific flags. This holds things like re-use
+                    // thread pane,
+  // configured for off-line use, use default retrieval, purge article/header
+  // options
+
+  uint16_t m_version;                // for upgrading...
+  int16_t m_IMAPHierarchySeparator;  // imap path separator
+
+  // mail only (for now)
+
+  // IMAP only
+  int32_t m_ImapUidValidity;
+  int32_t m_totalPendingMessages;
+  int32_t m_unreadPendingMessages;
+
+  // news only (for now)
+  nsMsgKey
+      m_expiredMark;  // Highest invalid article number in group - for expiring
+  // the db folder info will have to know what db and row it belongs to, since
+  // it is really just a wrapper around the singleton folder info row in the
+  // mdb.
+  nsMsgDatabase* m_mdb;
+  nsIMdbTable* m_mdbTable;  // singleton table in db
+  nsIMdbRow* m_mdbRow;      // singleton row in table;
+
+  bool m_mdbTokensInitialized;
+
+  mdb_token m_rowScopeToken;
+  mdb_token m_tableKindToken;
+  // tokens for the pre-set columns - we cache these for speed, which may be
+  // silly
+  mdb_token m_mailboxNameColumnToken;
+  mdb_token m_numMessagesColumnToken;
+  mdb_token m_numUnreadMessagesColumnToken;
+  mdb_token m_flagsColumnToken;
+  mdb_token m_folderSizeColumnToken;
+  mdb_token m_expungedBytesColumnToken;
+  mdb_token m_folderDateColumnToken;
+  mdb_token m_highWaterMessageKeyColumnToken;
+
+  mdb_token m_imapUidValidityColumnToken;
+  mdb_token m_totalPendingMessagesColumnToken;
+  mdb_token m_unreadPendingMessagesColumnToken;
+  mdb_token m_expiredMarkColumnToken;
+  mdb_token m_versionColumnToken;
+};
+
+#endif
diff --git a/comm/mailnews/db/msgdb/public/nsIDBChangeAnnouncer.idl b/comm/mailnews/db/msgdb/public/nsIDBChangeAnnouncer.idl
new file mode 100644
index 0000000000..afdb06f8ca
--- /dev/null
+++ b/comm/mailnews/db/msgdb/public/nsIDBChangeAnnouncer.idl
@@ -0,0 +1,42 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 "MailNewsTypes2.idl"
+
+interface nsIDBChangeListener;
+interface nsIMsgDBHdr;
+
+[scriptable, uuid(22baf00b-939d-42c3-ac51-21d99dfa1f05)]
+interface nsIDBChangeAnnouncer  : nsISupports {
+  void addListener(in nsIDBChangeListener listener);
+  void removeListener(in nsIDBChangeListener listener);
+
+  void notifyHdrChangeAll(in nsIMsgDBHdr aHdrChanged,
+                          in unsigned long aOldFlags,
+                          in unsigned long aNewFlags,
+                          in nsIDBChangeListener instigator);
+
+  void notifyHdrAddedAll(in nsIMsgDBHdr aHdrAdded,
+                         in nsMsgKey parentKey,
+                         in long flags,
+                         in nsIDBChangeListener instigator);
+
+  void notifyHdrDeletedAll(in nsIMsgDBHdr aHdrDeleted,
+                           in nsMsgKey parentKey,
+                           in long flags,
+                           in nsIDBChangeListener instigator);
+
+  void notifyParentChangedAll(in nsMsgKey keyReparented,
+                              in nsMsgKey oldParent,
+                              in nsMsgKey newParent,
+                              in nsIDBChangeListener instigator);
+
+  void notifyReadChanged(in nsIDBChangeListener instigator);
+
+  void notifyJunkScoreChanged(in nsIDBChangeListener aInstigator);
+
+  void notifyAnnouncerGoingAway();
+};
diff --git a/comm/mailnews/db/msgdb/public/nsIDBChangeListener.idl b/comm/mailnews/db/msgdb/public/nsIDBChangeListener.idl
new file mode 100644
index 0000000000..30c50db49c
--- /dev/null
+++ b/comm/mailnews/db/msgdb/public/nsIDBChangeListener.idl
@@ -0,0 +1,117 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 "MailNewsTypes2.idl"
+
+interface nsIDBChangeAnnouncer;
+interface nsIMsgDBHdr;
+interface nsIMsgDatabase;
+
+/**
+ * These callbacks are provided to allow listeners to the message database
+ * to update their status when changes occur.
+ */
+[scriptable, uuid(21c56d34-71b9-42bb-9606-331a6a5f8210)]
+
+interface  nsIDBChangeListener : nsISupports {
+  /**
+   * Callback when message flags are changed.
+   *
+   * @param aHdrChanged The changed header.
+   * @param aOldFlags   Message flags prior to change.
+   * @param aNewFlags   Message flags after change.
+   * @param aInstigator Object that initiated the change.
+   */
+  void onHdrFlagsChanged(in nsIMsgDBHdr aHdrChanged, in unsigned long aOldFlags,
+                   in unsigned long aNewFlags, in nsIDBChangeListener aInstigator);
+
+  /**
+   * Callback when message is marked as deleted.
+   *
+   * @param aHdrChanged The message header that is going to be deleted.
+   * @param aParentKey  Key of parent.
+   * @param aFlags      Flags that message has before delete.
+   * @param aInstigator Object that initiated the change. Can be null.
+   */
+  void onHdrDeleted(in nsIMsgDBHdr aHdrChanged, in nsMsgKey aParentKey, in long aFlags,
+                    in nsIDBChangeListener aInstigator);
+
+  /**
+   * Callback when message is added.
+   *
+   * @param aHdrChanged The message header that is added.
+   * @param aParentKey  Parent key of message.
+   * @param aFlags      Flags that new message will have.
+   * @param aInstigator Object that initiated the change. Can be null.
+   */
+  void onHdrAdded(in nsIMsgDBHdr aHdrChanged, in nsMsgKey aParentKey, in long aFlags,
+                  in nsIDBChangeListener aInstigator);
+
+  /**
+   * Callback when message parent is changed. Parent is changed when message is deleted or moved.
+   *
+   * @param aKeyChanged The message key that parent key was changed.
+   * @param oldParent   Old parent key.
+   * @param newParent   New parent key.
+   * @param aInstigator Object that initiated the change. Can be null.
+   */
+  void onParentChanged(in nsMsgKey aKeyChanged, in nsMsgKey oldParent, in nsMsgKey newParent,
+                       in nsIDBChangeListener aInstigator);
+
+  /**
+   * Callback when announcer is going away. This is good place to release strong pointers to announcer.
+   *
+   * @param instigator Object that initiated the change. Can be null.
+   */
+  void onAnnouncerGoingAway(in nsIDBChangeAnnouncer instigator);
+
+  /**
+   * Callback when read flag is changed.
+   *
+   * @param aInstigator Object that initiated the change. Can be null.
+   */
+  void onReadChanged(in nsIDBChangeListener aInstigator);
+
+  /**
+   * Callback used in case when "junkscore" property is changed.
+   *
+   * @param aInstigator Object that initiated the change. Can be null.
+   */
+  void onJunkScoreChanged(in nsIDBChangeListener aInstigator);
+
+  /**
+   * Callback used in the general case where any field may have changed.
+   * OnHdrPropertyChanged is called twice per change. On the first call, aPreChange
+   * is true, and aStatus is undefined. OnHdrPropertyChanged saves any required status in aStatus
+   * (such as a filter match). The calling function stores the value of aStatus, changes the
+   * header aHdrToChange, then calls OnHdrPropertyChanged again with aPreChange false. On this
+   * second call, the stored value of aStatus is provided, so that any changes may be noted.
+   *
+   * @param aHdrToChange the message header that is changing.
+   * @param aPreChange   true on first call before change, false on second call after change
+   * @param aStatus      storage location provided by calling routine for status
+   * @param aInstigator  object that initiated the change
+   */
+  void onHdrPropertyChanged(in nsIMsgDBHdr aHdrToChange,
+                            in AUTF8String property,
+                            in boolean aPreChange,
+                            inout uint32_t aStatus,
+                            in nsIDBChangeListener aInstigator);
+
+  /**
+   * Generic notification for extensibility. Common events should be documented
+   * here so we have a hope of keeping the documentation up to date.
+   * Current events are:
+   * "DBOpened" - When a pending listener becomes real. This can happen when
+   *              the existing db is force closed and a new one opened. Only
+   *              registered pending listeners are notified.
+   *
+   * @param aDB      the db for this event.
+   * @param aEvent   type of event.
+   *
+   */
+  void onEvent(in nsIMsgDatabase aDB, in string aEvent);
+};
diff --git a/comm/mailnews/db/msgdb/public/nsIDBFolderInfo.idl b/comm/mailnews/db/msgdb/public/nsIDBFolderInfo.idl
new file mode 100644
index 0000000000..cb41041268
--- /dev/null
+++ b/comm/mailnews/db/msgdb/public/nsIDBFolderInfo.idl
@@ -0,0 +1,94 @@
+/* -*- 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 "MailNewsTypes2.idl"
+
+[scriptable, uuid(a72dab4b-b3bd-471e-9a38-1b242b385459)]
+interface  nsIDBFolderInfo : nsISupports {
+  attribute long flags;
+
+  /**
+   * Or's aFlags into flags.
+   *
+   * @param - the flags(s) to set
+   *
+   * @return - the resulting flags.
+   */
+  long  orFlags(in long aFlags);
+  /**
+   * And's aFlags with flags, set flags to the result
+   *
+   * @param             the flags(s) to AND
+   *
+   * @return            the resulting flags.
+   */
+  long  andFlags(in long aFlags);
+
+  /**
+   * Allows us to keep track of the highwater mark
+   *
+   * @param aNewKey     If larger than the current highwater
+   *                    mark, sets the highwater mark to aNewKey.
+   */
+  void  onKeyAdded(in nsMsgKey aNewKey);
+
+  attribute nsMsgKey highWater;
+  attribute nsMsgKey expiredMark;
+  attribute long long folderSize;
+  attribute unsigned long folderDate;
+  void changeNumUnreadMessages(in long aDelta);
+  void changeNumMessages(in long aDelta);
+
+  // numUnreadMessages and numMessages will never return negative numbers. 0 means 'no msgs'.
+  attribute long numUnreadMessages;
+  attribute long numMessages;
+
+  attribute long long expungedBytes;
+  attribute long imapUidValidity;
+  attribute unsigned long version;
+  attribute long imapTotalPendingMessages;
+  attribute long imapUnreadPendingMessages;
+
+  attribute nsMsgViewTypeValue viewType;
+  attribute nsMsgViewFlagsTypeValue viewFlags;
+  attribute nsMsgViewSortTypeValue sortType;
+  attribute nsMsgViewSortOrderValue sortOrder;
+
+  void changeExpungedBytes(in long aDelta);
+
+  /**
+   * Gets a string property from the folder. Also used for URIs, hence the AUTF8String type.
+   *
+   * @param propertyName The name of the property for the value to retrieve.
+   */
+  AUTF8String getCharProperty(in string propertyName);
+
+  /**
+   * Sets a string property from the folder. Also used for URIs, hence the AUTF8String type.
+   *
+   * @param propertyName   The name of the property for which to set a value
+   * @param propertyValue  The new value of the property.
+   */
+  void setCharProperty(in string aPropertyName, in AUTF8String aPropertyValue);
+  void setUint32Property(in string propertyName, in unsigned long propertyValue);
+  void setInt64Property(in string propertyName, in long long propertyValue);
+  unsigned long getUint32Property(in string propertyName, in unsigned long defaultValue);
+  long long     getInt64Property(in string propertyName, in long long defaultValue);
+  boolean getBooleanProperty(in string propertyName, in boolean defaultValue);
+  void setBooleanProperty(in string propertyName, in boolean aPropertyValue);
+  nsIDBFolderInfo GetTransferInfo();
+  void initFromTransferInfo(in nsIDBFolderInfo transferInfo);
+
+  attribute AString locale;
+  attribute AString mailboxName;
+
+
+  AString getProperty(in string propertyName);
+  void setProperty(in string propertyName, in AString propertyStr);
+
+  attribute string knownArtsSet;
+  attribute ACString folderName;
+};
diff --git a/comm/mailnews/db/msgdb/public/nsIMsgDatabase.idl b/comm/mailnews/db/msgdb/public/nsIMsgDatabase.idl
new file mode 100644
index 0000000000..e54c938c15
--- /dev/null
+++ b/comm/mailnews/db/msgdb/public/nsIMsgDatabase.idl
@@ -0,0 +1,506 @@
+/* -*- 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/. */
+
+/**
+ * @defgroup msgdb Mailnews message database
+ * This module is the access point to locally-stored databases.
+ *
+ * These databases are stored in .msf files. Each file contains useful cached
+ * information, like the message id or references, as well as the cc header or
+ * tag information. This cached information is encapsulated in nsIMsgDBHdr.
+ *
+ * Also included is threading information, mostly encapsulated in nsIMsgThread.
+ * The final component is the database folder info, which contains information
+ * on the view and basic information also stored in the folder cache such as the
+ * name or most recent update.
+ *
+ * What this module does not do is access individual messages. Access is
+ * strictly controlled by the nsIMsgFolder objects and their backends.
+ * @{
+ */
+#include "nsISupports.idl"
+#include "nsIDBChangeAnnouncer.idl"
+
+interface nsIMsgDatabase;
+interface nsIDBChangeListener;
+interface nsIMsgDBHdr;
+interface nsIMsgEnumerator;
+interface nsIMsgThread;
+interface nsIMsgThreadEnumerator;
+interface nsIDBFolderInfo;
+interface nsIMsgOfflineImapOperation;
+interface nsIMsgFolder;
+interface nsIFile;
+interface nsIMsgSearchTerm;
+
+typedef unsigned long nsMsgRetainByPreference;
+
+
+[scriptable, uuid(fe8b7cec-eec8-4bcd-82ff-d8bb23cef3da)]
+
+interface nsIMsgRetentionSettings : nsISupports
+{
+  const unsigned long nsMsgRetainAll = 1;
+  const unsigned long nsMsgRetainByAge = 2;
+  const unsigned long nsMsgRetainByNumHeaders = 3;
+
+  attribute boolean useServerDefaults;
+  attribute nsMsgRetainByPreference retainByPreference;
+  attribute unsigned long daysToKeepHdrs;
+  attribute unsigned long numHeadersToKeep;
+
+  // this is for keeping offline bodies.
+  attribute boolean cleanupBodiesByDays;
+  attribute unsigned long daysToKeepBodies;
+
+  /**
+   * Should retention settings be applied to flagged/starred messages?
+   * If false, flagged messages are never automatically deleted.
+   */
+  attribute boolean applyToFlaggedMessages;
+};
+
+[scriptable, uuid(86a9da90-14f1-11d5-a5c0-0060b0fc04b7)]
+interface nsIMsgDownloadSettings : nsISupports
+{
+  attribute boolean useServerDefaults;
+  attribute boolean downloadByDate;
+  attribute boolean downloadUnreadOnly;
+  attribute unsigned long ageLimitOfMsgsToDownload;
+};
+
+typedef long nsMsgDBCommit;
+
+[scriptable, uuid(15431853-e448-45dc-8978-9958bf74d9b7)]
+interface nsMsgDBCommitType : nsISupports
+{
+  const long kLargeCommit = 1;
+  const long kSessionCommit = 2;
+  const long kCompressCommit = 3;
+};
+
+/**
+ * A service to open mail databases and manipulate listeners automatically.
+ *
+ * The contract ID for this component is
+ * <tt>\@mozilla.org/msgDatabase/msgDBService;1</tt>.
+ */
+[scriptable, uuid(4cbbf024-3760-402d-89f3-6ababafeb07d)]
+interface nsIMsgDBService : nsISupports
+{
+  /**
+   * Opens a database for a given folder.
+   *
+   * This method is preferred over nsIMsgDBService::openMailDBFromFile if the
+   * caller has an actual nsIMsgFolder around. If the database detects that it
+   * is unreadable or out of date (using nsIMsgDatabase::outOfDate) it will
+   * destroy itself and prepare to be rebuilt, unless aLeaveInvalidDB is true.
+   *
+   * If one gets a NS_MSG_ERROR_FOLDER_SUMMARY_MISSING message, then one
+   * should call nsIMsgDBService::createNewDB to create the new database.
+   *
+   * @param aFolder         The folder whose database should be returned.
+   * @param aLeaveInvalidDB Whether or not the database should be deleted if it
+   *                        is invalid.
+   * @return                A new nsIMsgDatabase object representing the folder
+   *                        database that was opened.
+   * @exception NS_ERROR_FILE_NOT_FOUND
+   *                        The file could not be created.
+   * @exception NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE
+   *                        The database is present (and was opened), but the
+   *                        summary file is out of date.
+   * @exception NS_MSG_ERROR_FOLDER_SUMMARY_MISSING
+   *                        The database is present, but the summary file is
+   *                        missing.
+   * @see nsIMsgDatabase::Open
+   * @see nsIMsgDBService::createNewDB
+   */
+  nsIMsgDatabase openFolderDB(in nsIMsgFolder aFolder,
+                              in boolean aLeaveInvalidDB);
+
+  /**
+   * Creates a new database for the given folder.
+   *
+   * If the database already exists, it will return the database, emit a
+   * warning, but not fully initialize it. For this reason, it should only be
+   * used when it is known that the database does not exist, such as when
+   * nsIMsgDBService::openFolderDB throws an error.
+   *
+   * @see nsIMsgDBService::openFolderDB
+   */
+  nsIMsgDatabase createNewDB(in nsIMsgFolder aFolder);
+
+  /**
+   * Opens or creates a database for a given file.
+   *
+   * This method should only be used if the caller does not have a folder
+   * instance, because the resulting db and message headers retrieved from the
+   * database would not know their owning folder, which limits their usefulness.
+   * For this reason, one should use nsIMsgDBService::openFolderDB instead
+   * except under special circumstances.
+   *
+   * Unlike nsIMsgDBService::openFolderDB, there is no corresponding method to
+   * create a new database if opening the database failed. However, this method
+   * will never throw NS_MSG_ERROR_FOLDER_SUMMARY_MISSING, so no corresponding
+   * method is needed.
+   *
+   * @param aFile           The file for which the database should be returned.
+   * @param aFolder         Folder the db corresponds to (may be null)
+   * @param aCreate         Whether or not the file should be created.
+   * @param aLeaveInvalidDB Whether or not the database should be deleted if it
+   *                        is invalid.
+   * @return                A new nsIMsgDatabase object encapsulating the file
+   *                        passed in.
+   * @exception NS_ERROR_FILE_NOT_FOUND
+   *                        The file could not be created.
+   * @see nsIMsgDBService::openFolderDB
+   * @see nsIMsgDatabase::Open
+   */
+  nsIMsgDatabase openMailDBFromFile(in nsIFile aFile,
+                                    in nsIMsgFolder aFolder,
+                                    in boolean aCreate,
+                                    in boolean aLeaveInvalidDB);
+  /**
+   * Adds the given listener to the listener set for the folder.
+   *
+   * Since the message database will likely be opened and closed many times, by
+   * registering using this method, one will be guaranteed to see all subsequent
+   * modifications. This will also add the listener to the database if it is
+   * already opened.
+   *
+   * @param aFolder         The folder to add a listener to.
+   * @param aListener       The listener to add the folder to.
+   */
+  void registerPendingListener(in nsIMsgFolder aFolder,
+                               in nsIDBChangeListener aListener);
+  /**
+   * Removes the listener from all folder listener sets.
+   *
+   * @param aListener       The listener to remove.
+   * @exception NS_ERROR_FAILURE
+   *                        The listener is not registered.
+   */
+  void unregisterPendingListener(in nsIDBChangeListener aListener);
+
+  /**
+   * Get the db for a folder, if already open.
+   *
+   * @param aFolder   The folder to get the cached (open) db for.
+   *
+   * @returns         null if the db isn't open, otherwise the db.
+   */
+  nsIMsgDatabase cachedDBForFolder(in nsIMsgFolder aFolder);
+
+  /**
+   * Close the db for a folder, if already open.
+   *
+   * @param aFolder   The folder to close the cached (open) db for.
+   */
+  void forceFolderDBClosed(in nsIMsgFolder aFolder);
+
+  /// an enumerator to iterate over the open dbs.
+  readonly attribute Array<nsIMsgDatabase> openDBs;
+};
+
+[scriptable, uuid(b64e66f8-4717-423a-be42-482658fb2199)]
+interface nsIMsgDatabase : nsIDBChangeAnnouncer {
+  void close(in boolean aForceCommit);
+
+  void commit(in nsMsgDBCommit commitType);
+  // Force closed is evil, and we should see if we can do without it.
+  // In 4.x, it was mainly used to remove corrupted databases.
+  void forceClosed();
+  void clearCachedHdrs();
+  void resetHdrCacheSize(in unsigned long size);
+
+  readonly attribute nsIDBFolderInfo  dBFolderInfo;
+
+  /// Size of the database file in bytes.
+  readonly attribute long long databaseSize;
+
+  /// Folder this db was opened on.
+  readonly attribute nsIMsgFolder folder;
+
+  /**
+   * This is used when deciding which db's to close to free up memory
+   * and other resources in an LRU manner. It doesn't track every operation
+   * on every object from the db, but high level things like open, commit,
+   * and perhaps some of the list methods. Commit should be a proxy for all
+   * the mutation methods.
+   *
+   * I'm allowing clients to set the last use time as well, so that
+   * nsIMsgFolder.msgDatabase can set the last use time.
+   */
+  attribute PRTime lastUseTime;
+
+  // get a message header for the given key. Caller must release()!
+
+  nsIMsgDBHdr getMsgHdrForKey(in nsMsgKey key);
+  nsIMsgDBHdr getMsgHdrForMessageID(in string messageID);
+
+  /**
+   * Get a message header for a Gmail message with the given X-GM-MSGID.
+   * @param {string} aGmailMessageID - The ID of the message to find.
+   *
+   * @returns the message, or null if not found (without throwing an error).
+   */
+  nsIMsgDBHdr getMsgHdrForGMMsgID(in string aGmailMessageID);
+  //Returns whether or not this database contains the given key
+  boolean containsKey(in nsMsgKey key);
+
+/**
+ * Must call AddNewHdrToDB after creating. The idea is that you create
+ * a new header, fill in its properties, and then call AddNewHdrToDB.
+ * AddNewHdrToDB will send notifications to any listeners.
+ *
+ * @param aKey msgKey for the new header. If aKey is nsMsgKey_None,
+ *             we will auto-assign a new key.
+ */
+  nsIMsgDBHdr createNewHdr(in nsMsgKey aKey);
+
+  void addNewHdrToDB(in nsIMsgDBHdr newHdr, in boolean notify);
+
+  nsIMsgDBHdr copyHdrFromExistingHdr(in nsMsgKey key, in nsIMsgDBHdr existingHdr, in boolean addHdrToDB);
+
+  /**
+   * Returns all message keys stored in the database.
+   * Keys are returned in the order as stored in the database.
+   * The caller should sort them if it needs to.
+   */
+  Array<nsMsgKey> listAllKeys();
+
+  nsIMsgEnumerator enumerateMessages();
+  nsIMsgEnumerator reverseEnumerateMessages();
+  nsIMsgThreadEnumerator enumerateThreads();
+
+  /**
+   * Get an enumerator of messages matching the passed-in search terms.
+   *
+   * @param searchTerms  Array of search terms to evaluate.
+   * @param reverse      Start at the end, defaults to false.
+   *
+   * @returns An enumerator to iterate over matching messages.
+   */
+  nsIMsgEnumerator getFilterEnumerator(in Array<nsIMsgSearchTerm> searchTerms,
+                                          [optional] in boolean reverse);
+
+  // count the total and unread msgs, and adjust global count if needed
+  void syncCounts();
+
+  nsIMsgThread getThreadContainingMsgHdr(in nsIMsgDBHdr msgHdr) ;
+
+  // helpers for user command functions like delete, mark read, etc.
+
+  void markHdrRead(in nsIMsgDBHdr msgHdr, in boolean bRead,
+                         in nsIDBChangeListener instigator);
+
+  void markHdrReplied(in nsIMsgDBHdr msgHdr, in boolean bReplied,
+                         in nsIDBChangeListener instigator);
+
+  void markHdrMarked(in nsIMsgDBHdr msgHdr, in boolean mark,
+                         in nsIDBChangeListener instigator);
+  /**
+   * Remove the new status from a message.
+   *
+   * @param aMsgHdr        The database reference header for the message
+   * @param aInstigator    Reference to original calling object
+   */
+  void markHdrNotNew(in nsIMsgDBHdr aMsgHdr,
+                     in nsIDBChangeListener aInstigator);
+
+  // MDN support
+  void markMDNNeeded(in nsMsgKey key, in boolean bNeeded,
+                           in nsIDBChangeListener instigator);
+
+  void markMDNSent(in nsMsgKey key, in boolean bNeeded,
+                         in nsIDBChangeListener instigator);
+  boolean isMDNSent(in nsMsgKey key);
+
+  void markRead(in nsMsgKey key, in boolean bRead,
+                      in nsIDBChangeListener instigator);
+
+  void markReplied(in nsMsgKey key, in boolean bReplied,
+                         in nsIDBChangeListener instigator);
+
+  void markForwarded(in nsMsgKey key, in boolean bForwarded,
+                           in nsIDBChangeListener instigator);
+
+  void markRedirected(in nsMsgKey key, in boolean bRedirected,
+                      in nsIDBChangeListener instigator);
+
+  void markHasAttachments(in nsMsgKey key, in boolean bHasAttachments,
+                                in nsIDBChangeListener instigator);
+
+  Array<nsMsgKey> markThreadRead(in nsIMsgThread thread, in nsIDBChangeListener instigator);
+
+  /// Mark the specified thread ignored.
+  void markThreadIgnored(in nsIMsgThread thread, in nsMsgKey threadKey,
+                         in boolean bIgnored,
+                         in nsIDBChangeListener instigator);
+
+  /// Mark the specified thread watched.
+  void markThreadWatched(in nsIMsgThread thread, in nsMsgKey threadKey,
+                         in boolean bWatched,
+                         in nsIDBChangeListener instigator);
+
+  /// Mark the specified subthread ignored.
+  void markHeaderKilled(in nsIMsgDBHdr msg, in boolean bIgnored,
+                        in nsIDBChangeListener instigator);
+
+  /// Is the message read.
+  boolean isRead(in nsMsgKey key);
+  /// Is the message part of an ignored thread.
+  boolean isIgnored(in nsMsgKey key);
+  /// Is the message part of a watched thread.
+  boolean isWatched(in nsMsgKey key);
+  /// Is the message flagged/starred.
+  boolean isMarked(in nsMsgKey key);
+  /// Does the message have attachments.
+  boolean hasAttachments(in nsMsgKey key);
+
+  Array<nsMsgKey> markAllRead();
+
+  void deleteMessages(in Array<nsMsgKey> nsMsgKeys,
+                      in nsIDBChangeListener instigator);
+  void deleteMessage(in nsMsgKey key,
+                           in nsIDBChangeListener instigator,
+                           in boolean commit);
+  void deleteHeader(in nsIMsgDBHdr msgHdr, in nsIDBChangeListener instigator,
+                          in boolean commit, in boolean notify);
+
+  /// Lower level routine that doesn't remove hdr from thread or adjust counts.
+  void removeHeaderMdbRow(in nsIMsgDBHdr msgHdr);
+
+  void undoDelete(in nsIMsgDBHdr msgHdr);
+
+  void markMarked(in nsMsgKey key, in boolean mark,
+                        in nsIDBChangeListener instigator);
+  void markOffline(in nsMsgKey key, in boolean offline,
+                         in nsIDBChangeListener instigator);
+  void setStringProperty(in nsMsgKey aKey, in string aProperty, in AUTF8String aValue);
+  /**
+   * Set the value of a string property in a message header
+   *
+   * @param msgHdr    Header of the message whose property will be changed
+   * @param aProperty the property to change
+   * @param aValue    new value for the property
+   */
+  void setStringPropertyByHdr(in nsIMsgDBHdr msgHdr, in string aProperty, in AUTF8String aValue);
+
+  /**
+   * Set the value of a uint32 property in a message header.
+   *
+   * @param aMsgHdr   header of the message whose property will be changed
+   * @param aProperty the property to change
+   * @param aValue    new value for the property
+   */
+  void setUint32PropertyByHdr(in nsIMsgDBHdr aMsgHdr,
+                              in string aProperty, in unsigned long aValue);
+
+  void markImapDeleted(in nsMsgKey key, in boolean deleted,
+                             in nsIDBChangeListener instigator);
+
+  readonly attribute nsMsgKey firstNew;
+
+  attribute nsIMsgRetentionSettings msgRetentionSettings;
+  // Purge unwanted message headers and/or bodies. If deleteViaFolder is
+  // true, we'll call nsIMsgFolder::DeleteMessages to delete the messages.
+  // Otherwise, we'll just delete them from the db.
+  void applyRetentionSettings(in nsIMsgRetentionSettings aMsgRetentionSettings,
+                              in boolean aDeleteViaFolder);
+
+  attribute nsIMsgDownloadSettings msgDownloadSettings;
+
+  boolean hasNew();
+  void clearNewList(in boolean notify);
+  void addToNewList(in nsMsgKey key);
+
+  // Used mainly to force the timestamp of a local mail folder db to
+  // match the time stamp of the corresponding berkeley mail folder,
+  // but also useful to tell the summary to mark itself invalid
+  // Also, if a local folder is being reparsed, summary will be invalid
+  // until the reparsing is done.
+  attribute boolean summaryValid;
+
+  Array<nsMsgKey> listAllOfflineMsgs();
+
+  void setAttributeOnPendingHdr(in nsIMsgDBHdr pendingHdr, in string property,
+                                  in string propertyVal);
+
+  void setUint32AttributeOnPendingHdr(in nsIMsgDBHdr pendingHdr, in string property,
+                                  in unsigned long propertyVal);
+
+  /**
+   * Sets a pending 64 bit attribute, which tells the DB that when a message
+   * which looks like the pendingHdr (e.g., same message-id) is added to the
+   * db, set the passed in property and value on the new header. This is
+   * usually because we've copied an imap message to a different folder, and
+   * want to carry forward attributes from the original message to the copy,
+   * but don't have the message hdr for the copy yet so we can't set
+   * attributes directly.
+   *
+   * @param aPendingHdr usually the source of the copy.
+   * @param aProperty name of property to set.
+   * @param aPropertyVal 64 bit value of property to set.
+   */
+  void setUint64AttributeOnPendingHdr(in nsIMsgDBHdr aPendingHdr,
+                                      in string aProperty,
+                                      in unsigned long long aPropertyVal);
+
+  /**
+   * Given a message header with its message-id set, update any pending
+   *  attributes on the header.
+   *
+   * @param aNewHdr a new header that may have pending attributes.
+   */
+  void updatePendingAttributes(in nsIMsgDBHdr aNewHdr);
+
+  readonly attribute nsMsgKey lowWaterArticleNum;
+  readonly attribute nsMsgKey highWaterArticleNum;
+  attribute nsMsgKey nextPseudoMsgKey;   //for undo-redo of move pop->imap
+  readonly attribute nsMsgKey nextFakeOfflineMsgKey; // for saving "fake" offline msg hdrs
+  // for sorting
+  Array<octet> createCollationKey(in AString sourceString);
+  long compareCollationKeys(in Array<octet> key1, in Array<octet> key2);
+
+  // when creating a view, the default sort order and view flags
+  // use these for the default.  (this allows news to override, so that
+  // news can be threaded by default)
+  readonly attribute nsMsgViewFlagsTypeValue defaultViewFlags;
+  readonly attribute nsMsgViewSortTypeValue  defaultSortType;
+  readonly attribute nsMsgViewSortOrderValue defaultSortOrder;
+
+  // for msg hdr hash table allocation. controllable by caller to improve folder loading performance.
+  attribute unsigned long msgHdrCacheSize;
+
+  /**
+   * The list of messages currently in the NEW state.
+   */
+  Array<nsMsgKey> getNewList();
+
+  // These are used for caching search hits in a db, to speed up saved search folders.
+  nsIMsgEnumerator getCachedHits(in AUTF8String aSearchFolderUri);
+
+  /**
+   * Update search cache to ensure it contains aNewHits.
+   *
+   * @param aSearchFolderUri the target folder.
+   * @param aNewHits sorted list of new message keys.
+   * @returns list of keys of messages removed from cache.
+   */
+  Array<nsMsgKey> refreshCache(in AUTF8String aSearchFolderUri, in Array<nsMsgKey> aNewHits);
+  void updateHdrInCache(in AUTF8String aSearchFolderUri, in nsIMsgDBHdr aHdr, in boolean aAdd);
+  boolean hdrIsInCache(in AUTF8String aSearchFolderUri, in nsIMsgDBHdr aHdr);
+};
+
+[scriptable, uuid(7f98410c-41b7-4a55-8e0c-02107e7f4c0f)]
+interface nsIMsgOfflineOpsDatabase : nsIMsgDatabase {
+  // Has to be in nsMailDatabase, since local folders can be move destinations.
+
+  nsIMsgOfflineImapOperation getOfflineOpForKey(in nsMsgKey messageKey, in boolean create);
+  void removeOfflineOp(in nsIMsgOfflineImapOperation op);
+  Array<nsMsgKey> listAllOfflineOpIds();
+  Array<nsMsgKey> listAllOfflineDeletes();
+};
diff --git a/comm/mailnews/db/msgdb/public/nsIMsgOfflineImapOperation.idl b/comm/mailnews/db/msgdb/public/nsIMsgOfflineImapOperation.idl
new file mode 100644
index 0000000000..bc2aecfa28
--- /dev/null
+++ b/comm/mailnews/db/msgdb/public/nsIMsgOfflineImapOperation.idl
@@ -0,0 +1,50 @@
+/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 "MailNewsTypes2.idl"
+#include "nsIImapUrl.idl" // for imapMessageFlagsType
+
+typedef long nsOfflineImapOperationType;
+
+[scriptable, uuid(b5229a55-22bb-444b-be92-13d719353828)]
+
+interface nsIMsgOfflineImapOperation : nsISupports
+{
+// type of stored imap operations
+  const long kFlagsChanged      = 0x1;
+  const long kMsgMoved          = 0x2;
+  const long kMsgCopy           = 0x4;
+  const long kMoveResult        = 0x8;
+  const long kAppendDraft       = 0x10;
+  const long kAddedHeader       = 0x20;
+  const long kDeletedMsg        = 0x40;
+  const long kMsgMarkedDeleted  = 0x80;
+  const long kAppendTemplate    = 0x100;
+  const long kDeleteAllMsgs     = 0x200;
+  const long kAddKeywords       = 0x400;
+  const long kRemoveKeywords    = 0x800;
+
+  attribute nsOfflineImapOperationType operation;
+  void clearOperation(in nsOfflineImapOperationType operation);
+  attribute nsMsgKey messageKey;
+
+  // for move/copy operations, the msg key of the source msg.
+  attribute nsMsgKey srcMessageKey;
+
+  attribute imapMessageFlagsType flagOperation;
+  attribute imapMessageFlagsType newFlags; // for kFlagsChanged
+  attribute AUTF8String destinationFolderURI; // for move or copy
+  attribute AUTF8String sourceFolderURI;
+  void addKeywordToAdd(in string aKeyword);
+  void addKeywordToRemove(in string aKeyword);
+  readonly attribute string keywordsToAdd;
+  readonly attribute string keywordsToRemove;
+  readonly attribute long numberOfCopies;
+  void addMessageCopyOperation(in AUTF8String destinationBox);
+  string getCopyDestination(in long copyIndex);
+  attribute unsigned long msgSize;
+  attribute boolean playingBack;
+};
diff --git a/comm/mailnews/db/msgdb/public/nsINewsDatabase.idl b/comm/mailnews/db/msgdb/public/nsINewsDatabase.idl
new file mode 100644
index 0000000000..151a42f019
--- /dev/null
+++ b/comm/mailnews/db/msgdb/public/nsINewsDatabase.idl
@@ -0,0 +1,18 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 "nsMsgKeySet.h"
+%}
+
+[ptr] native nsMsgKeySetPtr(nsMsgKeySet);
+
+[scriptable, uuid(f700208a-1dd1-11b2-b947-e4e1e4fdf278)]
+
+interface nsINewsDatabase : nsISupports {
+  [noscript] attribute nsMsgKeySetPtr readSet;
+};
diff --git a/comm/mailnews/db/msgdb/public/nsImapMailDatabase.h b/comm/mailnews/db/msgdb/public/nsImapMailDatabase.h
new file mode 100644
index 0000000000..307ad2ed0a
--- /dev/null
+++ b/comm/mailnews/db/msgdb/public/nsImapMailDatabase.h
@@ -0,0 +1,46 @@
+/* -*- 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 _nsImapMailDatabase_H_
+#define _nsImapMailDatabase_H_
+
+#include "mozilla/Attributes.h"
+#include "nsMailDatabase.h"
+
+class nsImapMailDatabase : public nsMailDatabase {
+ public:
+  // OK, it's dumb that this should require a fileSpec, since there is no file
+  // for the folder. This is mainly because we're deriving from nsMailDatabase;
+  // Perhaps we shouldn't...
+  nsImapMailDatabase();
+  virtual ~nsImapMailDatabase();
+
+  NS_IMETHOD GetSummaryValid(bool* aResult) override;
+  NS_IMETHOD SetSummaryValid(bool valid = true) override;
+  virtual nsresult AdjustExpungedBytesOnDelete(nsIMsgDBHdr* msgHdr) override;
+
+  NS_IMETHOD ForceClosed() override;
+  NS_IMETHOD AddNewHdrToDB(nsIMsgDBHdr* newHdr, bool notify) override;
+  NS_IMETHOD SetAttributeOnPendingHdr(nsIMsgDBHdr* pendingHdr,
+                                      const char* property,
+                                      const char* propertyVal) override;
+  NS_IMETHOD SetUint32AttributeOnPendingHdr(nsIMsgDBHdr* pendingHdr,
+                                            const char* property,
+                                            uint32_t propertyVal) override;
+  NS_IMETHOD SetUint64AttributeOnPendingHdr(nsIMsgDBHdr* aPendingHdr,
+                                            const char* aProperty,
+                                            uint64_t aPropertyVal) override;
+  NS_IMETHOD DeleteMessages(nsTArray<nsMsgKey> const& nsMsgKeys,
+                            nsIDBChangeListener* instigator) override;
+  NS_IMETHOD UpdatePendingAttributes(nsIMsgDBHdr* aNewHdr) override;
+
+ protected:
+  nsresult GetRowForPendingHdr(nsIMsgDBHdr* pendingHdr, nsIMdbRow** row);
+  nsresult GetAllPendingHdrsTable();
+  mdb_token m_pendingHdrsRowScopeToken;
+  mdb_token m_pendingHdrsTableKindToken;
+  nsCOMPtr<nsIMdbTable> m_mdbAllPendingHdrsTable;
+};
+
+#endif
diff --git a/comm/mailnews/db/msgdb/public/nsMailDatabase.h b/comm/mailnews/db/msgdb/public/nsMailDatabase.h
new file mode 100644
index 0000000000..4e29b26322
--- /dev/null
+++ b/comm/mailnews/db/msgdb/public/nsMailDatabase.h
@@ -0,0 +1,62 @@
+/* -*- 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 _nsMailDatabase_H_
+#define _nsMailDatabase_H_
+
+#include "mozilla/Attributes.h"
+#include "nsMsgDatabase.h"
+#include "nsTArray.h"
+
+#include "nsIDBChangeListener.h"
+#include "nsIMsgOfflineImapOperation.h"
+#include "nsISimpleEnumerator.h"
+#include "nsIFile.h"
+
+// This is the subclass of nsMsgDatabase that handles local mail messages.
+
+class nsMailDatabase : public nsMsgDatabase {
+ public:
+  nsMailDatabase();
+  virtual ~nsMailDatabase();
+  NS_IMETHOD ForceClosed() override;
+  NS_IMETHOD DeleteMessages(nsTArray<nsMsgKey> const& nsMsgKeys,
+                            nsIDBChangeListener* instigator) override;
+
+  nsresult Open(nsMsgDBService* aDBService, nsIFile* aSummaryFile, bool create,
+                bool upgrading) override;
+  virtual nsMailDatabase* GetMailDB() { return this; }
+
+  virtual uint32_t GetCurVersion() override { return kMsgDBVersion; }
+
+  NS_IMETHOD GetOfflineOpForKey(nsMsgKey opKey, bool create,
+                                nsIMsgOfflineImapOperation** op) override;
+  NS_IMETHOD RemoveOfflineOp(nsIMsgOfflineImapOperation* op) override;
+
+  NS_IMETHOD SetSummaryValid(bool valid) override;
+  NS_IMETHOD GetSummaryValid(bool* valid) override;
+
+  NS_IMETHOD ListAllOfflineOpIds(nsTArray<nsMsgKey>& offlineOpIds) override;
+  NS_IMETHOD ListAllOfflineDeletes(nsTArray<nsMsgKey>& offlineDeletes) override;
+
+  friend class nsMsgOfflineOpEnumerator;
+
+ protected:
+  nsresult GetAllOfflineOpsTable();  // get this on demand
+
+  // get the time and date of the mailbox file
+  void GetMailboxModProperties(int64_t* aSize, uint32_t* aDate);
+
+  nsCOMPtr<nsIMdbTable> m_mdbAllOfflineOpsTable;
+  mdb_token m_offlineOpsRowScopeToken;
+  mdb_token m_offlineOpsTableKindToken;
+
+  virtual void SetReparse(bool reparse);
+
+ protected:
+  bool m_reparse;
+};
+
+#endif
diff --git a/comm/mailnews/db/msgdb/public/nsMsgDatabase.h b/comm/mailnews/db/msgdb/public/nsMsgDatabase.h
new file mode 100644
index 0000000000..f61b9a7b25
--- /dev/null
+++ b/comm/mailnews/db/msgdb/public/nsMsgDatabase.h
@@ -0,0 +1,447 @@
+/* -*- 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 _nsMsgDatabase_H_
+#define _nsMsgDatabase_H_
+
+#include "mozilla/Attributes.h"
+#include "mozilla/MemoryReporting.h"
+#include "mozilla/Path.h"
+#include "nsIFile.h"
+#include "nsIMsgDatabase.h"
+#include "nsMsgHdr.h"
+#include "nsString.h"
+#include "nsIDBChangeAnnouncer.h"
+#include "nsMsgMessageFlags.h"
+#include "nsIMsgFolder.h"
+#include "nsDBFolderInfo.h"
+#include "mozilla/intl/Collator.h"
+#include "nsIMimeConverter.h"
+#include "nsCOMPtr.h"
+#include "nsCOMArray.h"
+#include "PLDHashTable.h"
+#include "nsTArray.h"
+#include "nsTObserverArray.h"
+
+using mozilla::intl::Collator;
+
+class nsMsgThread;
+class nsMsgDatabase;
+class nsIMsgOfflineOpsDatabase;
+class nsIMsgThread;
+class nsMsgDBEnumerator;
+class nsMsgDBThreadEnumerator;
+
+const int32_t kMsgDBVersion = 1;
+
+// Hopefully we're not opening up lots of databases at the same time, however
+// this will give us a buffer before we need to start reallocating the cache
+// array.
+const uint32_t kInitialMsgDBCacheSize = 20;
+
+class nsMsgDBService final : public nsIMsgDBService {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIMSGDBSERVICE
+
+  nsMsgDBService();
+
+  void AddToCache(nsMsgDatabase* pMessageDB);
+  void DumpCache();
+  void EnsureCached(nsMsgDatabase* pMessageDB) {
+    if (!m_dbCache.Contains(pMessageDB)) m_dbCache.AppendElement(pMessageDB);
+  }
+  void RemoveFromCache(nsMsgDatabase* pMessageDB) {
+    m_dbCache.RemoveElement(pMessageDB);
+  }
+
+ protected:
+  ~nsMsgDBService();
+  void HookupPendingListeners(nsIMsgDatabase* db, nsIMsgFolder* folder);
+  void FinishDBOpen(nsIMsgFolder* aFolder, nsMsgDatabase* aMsgDB);
+  nsMsgDatabase* FindInCache(nsIFile* dbName);
+
+  nsCOMArray<nsIMsgFolder> m_foldersPendingListeners;
+  nsCOMArray<nsIDBChangeListener> m_pendingListeners;
+  AutoTArray<nsMsgDatabase*, kInitialMsgDBCacheSize> m_dbCache;
+};
+
+namespace mozilla {
+namespace mailnews {
+class MsgDBReporter;
+}
+}  // namespace mozilla
+
+class nsMsgDatabase : public nsIMsgOfflineOpsDatabase {
+ public:
+  friend class nsMsgDBService;
+  friend class nsMsgPropertyEnumerator;  // accesses m_mdbEnv and m_mdbStore
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIDBCHANGEANNOUNCER
+  NS_DECL_NSIMSGDATABASE
+  NS_DECL_NSIMSGOFFLINEOPSDATABASE
+
+  /**
+   * Opens a database folder.
+   *
+   * @param aFolderName     The name of the folder to create.
+   * @param aCreate         Whether or not the file should be created.
+   * @param aLeaveInvalidDB Set to true if you do not want the database to be
+   *                        deleted if it is invalid.
+   * @exception NS_ERROR_FILE_NOT_FOUND
+   *                        The file could not be created.
+   * @exception NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE
+   *                        The database is present (and was opened), but the
+   *                        summary file is out of date.
+   * @exception NS_MSG_ERROR_FOLDER_SUMMARY_MISSING
+   *                        The database is present (and was opened), but the
+   *                        summary file is missing.
+   */
+  virtual nsresult Open(nsMsgDBService* aDBService, nsIFile* aFolderName,
+                        bool aCreate, bool aLeaveInvalidDB);
+  virtual nsresult IsHeaderRead(nsIMsgDBHdr* hdr, bool* pRead);
+  virtual nsresult MarkHdrReadInDB(nsIMsgDBHdr* msgHdr, bool bRead,
+                                   nsIDBChangeListener* instigator);
+  nsresult OpenInternal(nsMsgDBService* aDBService, nsIFile* aFolderName,
+                        bool aCreate, bool aLeaveInvalidDB, bool sync);
+  nsresult CheckForErrors(nsresult err, bool sync, nsMsgDBService* aDBService,
+                          nsIFile* summaryFile);
+  virtual nsresult OpenMDB(nsIFile* dbfile, bool create, bool sync);
+  virtual nsresult CloseMDB(bool commit);
+  virtual nsresult CreateMsgHdr(nsIMdbRow* hdrRow, nsMsgKey key,
+                                nsIMsgDBHdr** result);
+  virtual nsresult GetThreadForMsgKey(nsMsgKey msgKey, nsIMsgThread** result);
+  virtual nsresult EnumerateMessagesWithFlag(nsIMsgEnumerator** result,
+                                             uint32_t* pFlag);
+  nsresult GetSearchResultsTable(const nsACString& searchFolderUri,
+                                 bool createIfMissing, nsIMdbTable** table);
+
+  //////////////////////////////////////////////////////////////////////////////
+  // nsMsgDatabase methods:
+  nsMsgDatabase();
+
+  nsresult GetMDBFactory(nsIMdbFactory** aMdbFactory);
+  nsIMdbEnv* GetEnv() { return m_mdbEnv; }
+  nsIMdbStore* GetStore() { return m_mdbStore; }
+  virtual uint32_t GetCurVersion();
+  nsresult GetCollationKeyGenerator();
+  nsIMimeConverter* GetMimeConverter();
+
+  nsresult GetTableCreateIfMissing(const char* scope, const char* kind,
+                                   nsIMdbTable** table, mdb_token& scopeToken,
+                                   mdb_token& kindToken);
+
+  // helper function to fill in nsStrings from hdr row cell contents.
+  nsresult RowCellColumnTonsString(nsIMdbRow* row, mdb_token columnToken,
+                                   nsAString& resultStr);
+  nsresult RowCellColumnToUInt32(nsIMdbRow* row, mdb_token columnToken,
+                                 uint32_t* uint32Result,
+                                 uint32_t defaultValue = 0);
+  nsresult RowCellColumnToUInt32(nsIMdbRow* row, mdb_token columnToken,
+                                 uint32_t& uint32Result,
+                                 uint32_t defaultValue = 0);
+  nsresult RowCellColumnToUInt64(nsIMdbRow* row, mdb_token columnToken,
+                                 uint64_t* uint64Result,
+                                 uint64_t defaultValue = 0);
+  nsresult RowCellColumnToMime2DecodedString(nsIMdbRow* row,
+                                             mdb_token columnToken,
+                                             nsAString& resultStr);
+  nsresult RowCellColumnToCollationKey(nsIMdbRow* row, mdb_token columnToken,
+                                       nsTArray<uint8_t>& result);
+  nsresult RowCellColumnToConstCharPtr(nsIMdbRow* row, mdb_token columnToken,
+                                       const char** ptr);
+  nsresult RowCellColumnToAddressCollationKey(nsIMdbRow* row,
+                                              mdb_token colToken,
+                                              nsTArray<uint8_t>& result);
+
+  nsresult GetEffectiveCharset(nsIMdbRow* row, nsACString& resultCharset);
+
+  // these methods take the property name as a string, not a token.
+  // they should be used when the properties aren't accessed a lot
+  nsresult GetProperty(nsIMdbRow* row, const char* propertyName, char** result);
+  nsresult SetProperty(nsIMdbRow* row, const char* propertyName,
+                       const char* propertyVal);
+  nsresult GetPropertyAsNSString(nsIMdbRow* row, const char* propertyName,
+                                 nsAString& result);
+  nsresult SetPropertyFromNSString(nsIMdbRow* row, const char* propertyName,
+                                   const nsAString& propertyVal);
+  nsresult GetUint32Property(nsIMdbRow* row, const char* propertyName,
+                             uint32_t* result, uint32_t defaultValue = 0);
+  nsresult GetUint64Property(nsIMdbRow* row, const char* propertyName,
+                             uint64_t* result, uint64_t defaultValue = 0);
+  nsresult SetUint32Property(nsIMdbRow* row, const char* propertyName,
+                             uint32_t propertyVal);
+  nsresult SetUint64Property(nsIMdbRow* row, const char* propertyName,
+                             uint64_t propertyVal);
+  nsresult GetBooleanProperty(nsIMdbRow* row, const char* propertyName,
+                              bool* result, bool defaultValue = false);
+  nsresult SetBooleanProperty(nsIMdbRow* row, const char* propertyName,
+                              bool propertyVal);
+  // helper function for once we have the token.
+  nsresult SetNSStringPropertyWithToken(nsIMdbRow* row, mdb_token aProperty,
+                                        const nsAString& propertyStr);
+
+  // helper functions to put values in cells for the passed-in row
+  nsresult UInt32ToRowCellColumn(nsIMdbRow* row, mdb_token columnToken,
+                                 uint32_t value);
+  nsresult CharPtrToRowCellColumn(nsIMdbRow* row, mdb_token columnToken,
+                                  const char* charPtr);
+  nsresult RowCellColumnToCharPtr(nsIMdbRow* row, mdb_token columnToken,
+                                  char** result);
+  nsresult UInt64ToRowCellColumn(nsIMdbRow* row, mdb_token columnToken,
+                                 uint64_t value);
+
+  // helper functions to copy an nsString to a yarn, int32 to yarn, and vice
+  // versa.
+  static struct mdbYarn* nsStringToYarn(struct mdbYarn* yarn,
+                                        const nsAString& str);
+  static struct mdbYarn* UInt32ToYarn(struct mdbYarn* yarn, uint32_t i);
+  static struct mdbYarn* UInt64ToYarn(struct mdbYarn* yarn, uint64_t i);
+  static void YarnTonsString(struct mdbYarn* yarn, nsAString& str);
+  static void YarnTonsCString(struct mdbYarn* yarn, nsACString& str);
+  static void YarnToUInt32(struct mdbYarn* yarn, uint32_t* i);
+  static void YarnToUInt64(struct mdbYarn* yarn, uint64_t* i);
+
+#ifdef DEBUG
+  virtual nsresult DumpContents();
+#endif
+
+  friend class nsMsgHdr;     // use this to get access to cached tokens for hdr
+                             // fields
+  friend class nsMsgThread;  // use this to get access to cached tokens for hdr
+                             // fields
+
+  friend class nsMsgDBEnumerator;
+  friend class nsMsgDBThreadEnumerator;
+
+ protected:
+  virtual ~nsMsgDatabase();
+
+  // prefs stuff - in future, we might want to cache the prefs interface
+  nsresult GetBoolPref(const char* prefName, bool* result);
+  nsresult GetIntPref(const char* prefName, int32_t* result);
+  virtual void GetGlobalPrefs();
+  // retrieval methods
+  nsIMsgThread* GetThreadForReference(nsCString& msgID, nsIMsgDBHdr** pMsgHdr);
+  nsIMsgThread* GetThreadForSubject(nsCString& subject);
+  nsIMsgThread* GetThreadForMessageId(nsCString& msgId);
+  nsIMsgThread* GetThreadForThreadId(nsMsgKey threadId);
+  nsMsgHdr* GetMsgHdrForReference(nsCString& reference);
+  nsIMsgDBHdr* GetMsgHdrForSubject(nsCString& subject);
+  // threading interfaces
+  virtual nsresult CreateNewThread(nsMsgKey key, const char* subject,
+                                   nsMsgThread** newThread);
+  virtual bool ThreadBySubjectWithoutRe();
+  virtual bool UseStrictThreading();
+  virtual bool UseCorrectThreading();
+  virtual nsresult ThreadNewHdr(nsMsgHdr* hdr, bool& newThread);
+  virtual nsresult AddNewThread(nsMsgHdr* msgHdr);
+  virtual nsresult AddToThread(nsMsgHdr* newHdr, nsIMsgThread* thread,
+                               nsIMsgDBHdr* pMsgHdr, bool threadInThread);
+
+  static PRTime gLastUseTime;  // global last use time
+  PRTime m_lastUseTime;        // last use time for this db
+  // inline to make instrumentation as cheap as possible
+  inline void RememberLastUseTime() { gLastUseTime = m_lastUseTime = PR_Now(); }
+
+  bool MatchDbName(nsIFile* dbName);  // returns TRUE if they match
+
+  // Flag handling routines
+  virtual nsresult SetKeyFlag(nsMsgKey key, bool set, nsMsgMessageFlagType flag,
+                              nsIDBChangeListener* instigator = nullptr);
+  virtual nsresult SetMsgHdrFlag(nsIMsgDBHdr* msgHdr, bool set,
+                                 nsMsgMessageFlagType flag,
+                                 nsIDBChangeListener* instigator);
+
+  virtual bool SetHdrFlag(nsIMsgDBHdr*, bool bSet, nsMsgMessageFlagType flag);
+  virtual bool SetHdrReadFlag(nsIMsgDBHdr*, bool pRead);
+  virtual uint32_t GetStatusFlags(nsIMsgDBHdr* msgHdr,
+                                  nsMsgMessageFlagType origFlags);
+  // helper function which doesn't involve thread object
+
+  virtual nsresult RemoveHeaderFromDB(nsMsgHdr* msgHdr);
+  virtual nsresult RemoveHeaderFromThread(nsMsgHdr* msgHdr);
+  virtual nsresult AdjustExpungedBytesOnDelete(nsIMsgDBHdr* msgHdr);
+
+  mozilla::UniquePtr<mozilla::intl::Collator> m_collationKeyGenerator = nullptr;
+  nsCOMPtr<nsIMimeConverter> m_mimeConverter;
+  nsCOMPtr<nsIMsgRetentionSettings> m_retentionSettings;
+  nsCOMPtr<nsIMsgDownloadSettings> m_downloadSettings;
+
+  nsresult FindMessagesOlderThan(uint32_t daysToKeepHdrs,
+                                 bool applyToFlaggedMessages,
+                                 nsTArray<RefPtr<nsIMsgDBHdr>>& hdrsToDelete);
+  nsresult FindExcessMessages(uint32_t numHeadersToKeep,
+                              bool applyToFlaggedMessages,
+                              nsTArray<RefPtr<nsIMsgDBHdr>>& hdrsToDelete);
+
+  // mdb bookkeeping stuff
+  virtual nsresult InitExistingDB();
+  virtual nsresult InitNewDB();
+  virtual nsresult InitMDBInfo();
+
+  nsCOMPtr<nsIMsgFolder> m_folder;
+  RefPtr<nsDBFolderInfo> m_dbFolderInfo;
+  nsMsgKey m_nextPseudoMsgKey;
+  nsIMdbEnv* m_mdbEnv;  // to be used in all the db calls.
+  nsIMdbStore* m_mdbStore;
+  nsIMdbTable* m_mdbAllMsgHeadersTable;
+  nsIMdbTable* m_mdbAllThreadsTable;
+
+  // Used for asynchronous db opens. If non-null, we're still opening
+  // the underlying mork database. If null, the db has been completely opened.
+  nsCOMPtr<nsIMdbThumb> m_thumb;
+  // used to remember the args to Open for async open.
+  bool m_create;
+  bool m_leaveInvalidDB;
+
+  nsCOMPtr<nsIFile> m_dbFile;
+  nsTArray<nsMsgKey> m_newSet;  // new messages since last open.
+  bool m_mdbTokensInitialized;
+  nsTObserverArray<nsCOMPtr<nsIDBChangeListener>> m_ChangeListeners;
+  mdb_token m_hdrRowScopeToken;
+  mdb_token m_threadRowScopeToken;
+  mdb_token m_hdrTableKindToken;
+  mdb_token m_threadTableKindToken;
+  mdb_token m_allThreadsTableKindToken;
+  mdb_token m_subjectColumnToken;
+  mdb_token m_senderColumnToken;
+  mdb_token m_messageIdColumnToken;
+  mdb_token m_referencesColumnToken;
+  mdb_token m_recipientsColumnToken;
+  mdb_token m_dateColumnToken;
+  mdb_token m_messageSizeColumnToken;
+  mdb_token m_flagsColumnToken;
+  mdb_token m_priorityColumnToken;
+  mdb_token m_labelColumnToken;
+  mdb_token m_numLinesColumnToken;
+  mdb_token m_ccListColumnToken;
+  mdb_token m_bccListColumnToken;
+  mdb_token m_threadFlagsColumnToken;
+  mdb_token m_threadIdColumnToken;
+  mdb_token m_threadChildrenColumnToken;
+  mdb_token m_threadUnreadChildrenColumnToken;
+  mdb_token m_messageThreadIdColumnToken;
+  mdb_token m_threadSubjectColumnToken;
+  mdb_token m_messageCharSetColumnToken;
+  mdb_token m_threadParentColumnToken;
+  mdb_token m_threadRootKeyColumnToken;
+  mdb_token m_threadNewestMsgDateColumnToken;
+  mdb_token m_offlineMsgOffsetColumnToken;
+  mdb_token m_offlineMessageSizeColumnToken;
+
+  // header caching stuff - MRU headers, keeps them around in memory
+  nsresult AddHdrToCache(nsIMsgDBHdr* hdr, nsMsgKey key);
+  nsresult ClearHdrCache(bool reInit);
+  nsresult RemoveHdrFromCache(nsIMsgDBHdr* hdr, nsMsgKey key);
+  // all headers currently instantiated, doesn't hold refs
+  // these get added when msg hdrs get constructed, and removed when they get
+  // destroyed.
+  nsresult GetHdrFromUseCache(nsMsgKey key, nsIMsgDBHdr** result);
+  nsresult AddHdrToUseCache(nsIMsgDBHdr* hdr, nsMsgKey key);
+  nsresult ClearUseHdrCache();
+  nsresult RemoveHdrFromUseCache(nsIMsgDBHdr* hdr, nsMsgKey key);
+
+  // not-reference holding array of threads we've handed out.
+  // If a db goes away, it will clean up the outstanding threads.
+  // We use an nsTArray because we don't expect to ever have very many
+  // of these, rarely more than 5.
+  nsTArray<nsMsgThread*> m_threads;
+  // Clear outstanding thread objects
+  void ClearThreads();
+  nsMsgThread* FindExistingThread(nsMsgKey threadId);
+
+  mdb_pos FindInsertIndexInSortedTable(nsIMdbTable* table, mdb_id idToInsert);
+
+  void ClearCachedObjects(bool dbGoingAway);
+  void InvalidateEnumerators();
+  // all instantiated headers, but doesn't hold refs.
+  PLDHashTable* m_headersInUse;
+  static PLDHashNumber HashKey(const void* aKey);
+  static bool MatchEntry(const PLDHashEntryHdr* aEntry, const void* aKey);
+  static void MoveEntry(PLDHashTable* aTable, const PLDHashEntryHdr* aFrom,
+                        PLDHashEntryHdr* aTo);
+  static void ClearEntry(PLDHashTable* aTable, PLDHashEntryHdr* aEntry);
+  static PLDHashTableOps gMsgDBHashTableOps;
+  struct MsgHdrHashElement : public PLDHashEntryHdr {
+    nsMsgKey mKey;
+    nsIMsgDBHdr* mHdr;
+  };
+  PLDHashTable* m_cachedHeaders;
+  bool m_bCacheHeaders;
+  nsMsgKey m_cachedThreadId;
+  nsCOMPtr<nsIMsgThread> m_cachedThread;
+  nsCOMPtr<nsIMdbFactory> mMdbFactory;
+
+  // Message reference hash table
+  static PLDHashTableOps gRefHashTableOps;
+  struct RefHashElement : public PLDHashEntryHdr {
+    const char* mRef;  // Hash entry key, must come first
+    nsMsgKey mThreadId;
+    uint32_t mCount;
+  };
+  PLDHashTable* m_msgReferences;
+  nsresult GetRefFromHash(nsCString& reference, nsMsgKey* threadId);
+  nsresult AddRefToHash(nsCString& reference, nsMsgKey threadId);
+  nsresult AddMsgRefsToHash(nsIMsgDBHdr* msgHdr);
+  nsresult RemoveRefFromHash(nsCString& reference);
+  nsresult RemoveMsgRefsFromHash(nsIMsgDBHdr* msgHdr);
+  nsresult InitRefHash();
+
+  // The enumerators add themselves to these lists.
+  // If a db goes away - via destruction or ForceClosed() - it needs to
+  // invalidate any outstanding enumerators.
+  nsTArray<nsMsgDBEnumerator*> m_msgEnumerators;
+  nsTArray<nsMsgDBThreadEnumerator*> m_threadEnumerators;
+
+  // Memory reporter details
+ public:
+  static size_t HeaderHashSizeOf(PLDHashEntryHdr* hdr,
+                                 mozilla::MallocSizeOf aMallocSizeOf,
+                                 void* arg);
+  virtual size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
+  virtual size_t SizeOfIncludingThis(
+      mozilla::MallocSizeOf aMallocSizeOf) const {
+    return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+  }
+
+ private:
+  uint32_t m_cacheSize;
+  RefPtr<mozilla::mailnews::MsgDBReporter> mMemReporter;
+};
+
+class nsMsgRetentionSettings : public nsIMsgRetentionSettings {
+ public:
+  nsMsgRetentionSettings();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIMSGRETENTIONSETTINGS
+ protected:
+  virtual ~nsMsgRetentionSettings();
+  nsMsgRetainByPreference m_retainByPreference;
+  uint32_t m_daysToKeepHdrs;
+  uint32_t m_numHeadersToKeep;
+  bool m_useServerDefaults;
+  bool m_cleanupBodiesByDays;
+  uint32_t m_daysToKeepBodies;
+  bool m_applyToFlaggedMessages;
+};
+
+class nsMsgDownloadSettings : public nsIMsgDownloadSettings {
+ public:
+  nsMsgDownloadSettings();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIMSGDOWNLOADSETTINGS
+ protected:
+  virtual ~nsMsgDownloadSettings();
+  bool m_useServerDefaults;
+  bool m_downloadUnreadOnly;
+  bool m_downloadByDate;
+  int32_t m_ageLimitOfMsgsToDownload;
+};
+
+#endif
diff --git a/comm/mailnews/db/msgdb/public/nsMsgHdr.h b/comm/mailnews/db/msgdb/public/nsMsgHdr.h
new file mode 100644
index 0000000000..94e5b1b8c8
--- /dev/null
+++ b/comm/mailnews/db/msgdb/public/nsMsgHdr.h
@@ -0,0 +1,92 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 _nsMsgHdr_H
+#define _nsMsgHdr_H
+
+#include "mozilla/MemoryReporting.h"
+#include "nsIMsgHdr.h"
+#include "nsString.h"
+#include "MailNewsTypes.h"
+#include "mdb.h"
+#include "nsTArray.h"
+
+class nsMsgDatabase;
+class nsIMsgThread;
+
+class nsMsgHdr : public nsIMsgDBHdr {
+ public:
+  NS_DECL_NSIMSGDBHDR
+  friend class nsMsgDatabase;
+  friend class nsImapMailDatabase;
+  friend class nsMsgPropertyEnumerator;
+  friend class nsMsgThread;
+
+  ////////////////////////////////////////////////////////////////////////////
+  ////////////////////////////////////////////////////////////////////////////
+  // nsMsgHdr methods:
+  nsMsgHdr(nsMsgDatabase* db, nsIMdbRow* dbRow);
+
+  NS_DECL_ISUPPORTS
+
+  size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOfFun) const {
+    return m_references.ShallowSizeOfExcludingThis(aMallocSizeOfFun);
+  }
+  size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOfFun) const {
+    return aMallocSizeOfFun(this) + SizeOfExcludingThis(aMallocSizeOfFun);
+  }
+
+ protected:
+  nsIMdbRow* GetMDBRow() { return m_mdbRow; }
+  void ReleaseMDBRow() { NS_IF_RELEASE(m_mdbRow); }
+  nsMsgDatabase* GetMdb() { return m_mdb; }
+  void ClearCachedValues() { m_initedValues = 0; }
+
+  virtual nsresult GetRawFlags(uint32_t* result);
+
+  bool IsParentOf(nsIMsgDBHdr* possibleChild);
+  bool IsAncestorOf(nsIMsgDBHdr* possibleChild);
+
+ private:
+  virtual ~nsMsgHdr();
+
+  void Init();
+  virtual nsresult InitFlags();
+  virtual nsresult InitCachedValues();
+
+  bool IsAncestorKilled(uint32_t ancestorsToCheck);
+  void ReparentInThread(nsIMsgThread* thread);
+
+  nsresult SetStringColumn(const char* str, mdb_token token);
+  nsresult SetUInt32Column(uint32_t value, mdb_token token);
+  nsresult GetUInt32Column(mdb_token token, uint32_t* pvalue,
+                           uint32_t defaultValue = 0);
+  nsresult SetUInt64Column(uint64_t value, mdb_token token);
+  nsresult GetUInt64Column(mdb_token token, uint64_t* pvalue,
+                           uint64_t defaultValue = 0);
+
+  // reference and threading stuff.
+  nsresult ParseReferences(const char* references);
+  const char* GetNextReference(const char* startNextRef, nsCString& reference,
+                               bool acceptNonDelimitedReferences);
+
+  nsMsgKey m_threadId;
+  nsMsgKey m_messageKey;  // news: article number, local mail: key, imap: uid...
+  nsMsgKey m_threadParent;  // message this is a reply to, in thread.
+  PRTime m_date;
+  uint32_t m_messageSize;  // lines for news articles, bytes for mail messages
+  uint32_t m_flags;
+  // avoid parsing references every time we want one
+  nsTArray<nsCString> m_references;
+
+  // nsMsgHdrs will have to know what db and row they belong to, since they are
+  // really just a wrapper around the msg row in the mdb. This could cause
+  // problems, though I hope not.
+  nsMsgDatabase* m_mdb;
+  nsIMdbRow* m_mdbRow;
+  uint32_t m_initedValues;
+};
+
+#endif
diff --git a/comm/mailnews/db/msgdb/public/nsMsgThread.h b/comm/mailnews/db/msgdb/public/nsMsgThread.h
new file mode 100644
index 0000000000..37add58082
--- /dev/null
+++ b/comm/mailnews/db/msgdb/public/nsMsgThread.h
@@ -0,0 +1,65 @@
+/* -*- 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/. */
+
+#ifndef _nsMsgThread_H
+#define _nsMsgThread_H
+
+#include "nsIMsgThread.h"
+#include "nsString.h"
+#include "MailNewsTypes.h"
+#include "mdb.h"
+
+class nsIMdbTable;
+class nsIMsgDBHdr;
+class nsMsgDatabase;
+
+class nsMsgThread : public nsIMsgThread {
+ public:
+  nsMsgThread();
+  nsMsgThread(nsMsgDatabase* db, nsIMdbTable* table);
+
+  friend class nsMsgThreadEnumerator;
+  friend class nsMsgDatabase;
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIMSGTHREAD
+
+  RefPtr<nsMsgDatabase> m_mdbDB;
+
+ protected:
+  virtual ~nsMsgThread();
+
+  void Init();
+  void Clear();
+  virtual nsresult InitCachedValues();
+  nsresult ChangeChildCount(int32_t delta);
+  nsresult ChangeUnreadChildCount(int32_t delta);
+  nsresult RemoveChild(nsMsgKey msgKey);
+  nsresult SetThreadRootKey(nsMsgKey threadRootKey);
+  nsresult GetChildHdrForKey(nsMsgKey desiredKey, nsIMsgDBHdr** result,
+                             int32_t* resultIndex);
+  nsresult RerootThread(nsIMsgDBHdr* newParentOfOldRoot, nsIMsgDBHdr* oldRoot,
+                        nsIDBChangeAnnouncer* announcer);
+  nsresult ReparentChildrenOf(nsMsgKey oldParent, nsMsgKey newParent,
+                              nsIDBChangeAnnouncer* announcer);
+
+  nsresult ReparentNonReferenceChildrenOf(nsIMsgDBHdr* topLevelHdr,
+                                          nsMsgKey newParentKey,
+                                          nsIDBChangeAnnouncer* announcer);
+  nsresult ReparentMsgsWithInvalidParent(uint32_t numChildren,
+                                         nsMsgKey threadParentKey);
+
+  nsMsgKey m_threadKey;
+  uint32_t m_numChildren;
+  uint32_t m_numUnreadChildren;
+  uint32_t m_flags;
+  nsCOMPtr<nsIMdbTable> m_mdbTable;
+  nsCOMPtr<nsIMdbRow> m_metaRow;
+  bool m_cachedValuesInitialized;
+  nsMsgKey m_threadRootKey;
+  uint32_t m_newestMsgDate;
+};
+
+#endif
diff --git a/comm/mailnews/db/msgdb/public/nsNewsDatabase.h b/comm/mailnews/db/msgdb/public/nsNewsDatabase.h
new file mode 100644
index 0000000000..4a804d0d69
--- /dev/null
+++ b/comm/mailnews/db/msgdb/public/nsNewsDatabase.h
@@ -0,0 +1,57 @@
+/* -*- 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 _nsNewsDatabase_H_
+#define _nsNewsDatabase_H_
+
+#include "mozilla/Attributes.h"
+#include "nsMsgDatabase.h"
+#include "nsINewsDatabase.h"
+#include "nsTArray.h"
+#include "nsIMsgHdr.h"
+
+// news group database
+
+class nsNewsDatabase : public nsMsgDatabase, public nsINewsDatabase {
+ public:
+  nsNewsDatabase();
+
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_NSINEWSDATABASE
+
+  NS_IMETHOD Close(bool forceCommit) override;
+  NS_IMETHOD ForceClosed() override;
+  NS_IMETHOD Commit(nsMsgDBCommit commitType) override;
+  virtual uint32_t GetCurVersion() override;
+
+  // methods to get and set docsets for ids.
+  NS_IMETHOD IsRead(nsMsgKey key, bool* pRead) override;
+  virtual nsresult IsHeaderRead(nsIMsgDBHdr* msgHdr, bool* pRead) override;
+
+  NS_IMETHOD GetHighWaterArticleNum(nsMsgKey* key) override;
+  NS_IMETHOD GetLowWaterArticleNum(nsMsgKey* key) override;
+  NS_IMETHOD MarkAllRead(nsTArray<nsMsgKey>& thoseMarked) override;
+
+  virtual nsresult ExpireUpTo(nsMsgKey expireKey);
+  virtual nsresult ExpireRange(nsMsgKey startRange, nsMsgKey endRange);
+
+  virtual bool SetHdrReadFlag(nsIMsgDBHdr* msgHdr, bool bRead) override;
+
+  virtual nsresult AdjustExpungedBytesOnDelete(nsIMsgDBHdr* msgHdr) override;
+  nsresult SyncWithReadSet();
+
+  NS_IMETHOD GetDefaultViewFlags(
+      nsMsgViewFlagsTypeValue* aDefaultViewFlags) override;
+  NS_IMETHOD GetDefaultSortType(
+      nsMsgViewSortTypeValue* aDefaultSortType) override;
+  NS_IMETHOD GetDefaultSortOrder(
+      nsMsgViewSortOrderValue* aDefaultSortOrder) override;
+
+ protected:
+  virtual ~nsNewsDatabase();
+  // this is owned by the nsNewsFolder, which lives longer than the db.
+  nsMsgKeySet* m_readSet;
+};
+
+#endif
diff --git a/comm/mailnews/db/msgdb/src/components.conf b/comm/mailnews/db/msgdb/src/components.conf
new file mode 100644
index 0000000000..1d65e685f2
--- /dev/null
+++ b/comm/mailnews/db/msgdb/src/components.conf
@@ -0,0 +1,44 @@
+# 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 = [
+    {
+        "cid": "{a86c86ae-e97f-11d2-a506-0060b0fc04b7}",
+        "contract_ids": ["@mozilla.org/nsMsgDatabase/msgDB-mailbox"],
+        "type": "nsMailDatabase",
+        "headers": ["/comm/mailnews/db/msgdb/public/nsMailDatabase.h"],
+    },
+    {
+        "cid": "{36414aa0-e980-11d2-a506-0060b0fc04b7}",
+        "contract_ids": ["@mozilla.org/nsMsgDatabase/msgDB-news"],
+        "type": "nsNewsDatabase",
+        "headers": ["/comm/mailnews/db/msgdb/public/nsNewsDatabase.h"],
+    },
+    {
+        "cid": "{9e4b07ee-e980-11d2-a506-0060b0fc04b7}",
+        "contract_ids": ["@mozilla.org/nsMsgDatabase/msgDB-imap"],
+        "type": "nsImapMailDatabase",
+        "headers": ["/comm/mailnews/db/msgdb/public/nsImapMailDatabase.h"],
+    },
+    {
+        "cid": "{1bd976d6-df44-11d4-a5b6-0060b0fc04b7}",
+        "contract_ids": ["@mozilla.org/msgDatabase/retentionSettings;1"],
+        "type": "nsMsgRetentionSettings",
+        "headers": ["/comm/mailnews/db/msgdb/public/nsMsgDatabase.h"],
+    },
+    {
+        "cid": "{4e3dae5a-157a-11d5-a5c0-0060b0fc04b7}",
+        "contract_ids": ["@mozilla.org/msgDatabase/downloadSettings;1"],
+        "type": "nsMsgDownloadSettings",
+        "headers": ["/comm/mailnews/db/msgdb/public/nsMsgDatabase.h"],
+    },
+    {
+        "cid": "{03223c50-1e88-45e8-ba1a-7ce792dc3fc3}",
+        "contract_ids": ["@mozilla.org/msgDatabase/msgDBService;1"],
+        "type": "nsMsgDBService",
+        "headers": ["/comm/mailnews/db/msgdb/public/nsMsgDatabase.h"],
+        "name": "DB",
+        "interfaces": ["nsIMsgDBService"],
+    },
+]
diff --git a/comm/mailnews/db/msgdb/src/moz.build b/comm/mailnews/db/msgdb/src/moz.build
new file mode 100644
index 0000000000..06c2b92475
--- /dev/null
+++ b/comm/mailnews/db/msgdb/src/moz.build
@@ -0,0 +1,22 @@
+# 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/.
+
+SOURCES += [
+    "nsDBFolderInfo.cpp",
+    "nsImapMailDatabase.cpp",
+    "nsMailDatabase.cpp",
+    "nsMsgDatabase.cpp",
+    "nsMsgDatabaseEnumerators.cpp",
+    "nsMsgHdr.cpp",
+    "nsMsgOfflineImapOperation.cpp",
+    "nsMsgThread.cpp",
+    "nsNewsDatabase.cpp",
+]
+
+FINAL_LIBRARY = "mail"
+
+XPCOM_MANIFESTS += [
+    "components.conf",
+]
diff --git a/comm/mailnews/db/msgdb/src/nsDBFolderInfo.cpp b/comm/mailnews/db/msgdb/src/nsDBFolderInfo.cpp
new file mode 100644
index 0000000000..57118ffaf8
--- /dev/null
+++ b/comm/mailnews/db/msgdb/src/nsDBFolderInfo.cpp
@@ -0,0 +1,749 @@
+/* -*- 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 "msgCore.h"
+#include "nsDBFolderInfo.h"
+#include "nsMsgDatabase.h"
+#include "nsMsgFolderFlags.h"
+#include "nsIPrefService.h"
+#include "nsIPrefBranch.h"
+#include "nsIPrefLocalizedString.h"
+#include "nsIObserver.h"
+#include "nsIObserverService.h"
+#include "nsIMsgDBView.h"
+#include "nsServiceManagerUtils.h"
+#include "nsImapCore.h"
+
+static const char* kDBFolderInfoScope = "ns:msg:db:row:scope:dbfolderinfo:all";
+static const char* kDBFolderInfoTableKind = "ns:msg:db:table:kind:dbfolderinfo";
+
+struct mdbOid gDBFolderInfoOID;
+
+static const char* kNumMessagesColumnName = "numMsgs";
+// have to leave this as numNewMsgs even though it's numUnread Msgs
+static const char* kNumUnreadMessagesColumnName = "numNewMsgs";
+static const char* kFlagsColumnName = "flags";
+static const char* kFolderSizeColumnName = "folderSize";
+static const char* kExpungedBytesColumnName = "expungedBytes";
+static const char* kFolderDateColumnName = "folderDate";
+static const char* kHighWaterMessageKeyColumnName = "highWaterKey";
+
+static const char* kImapUidValidityColumnName = "UIDValidity";
+static const char* kTotalPendingMessagesColumnName = "totPendingMsgs";
+static const char* kUnreadPendingMessagesColumnName = "unreadPendingMsgs";
+static const char* kMailboxNameColumnName = "mailboxName";
+static const char* kKnownArtsSetColumnName = "knownArts";
+static const char* kExpiredMarkColumnName = "expiredMark";
+static const char* kVersionColumnName = "version";
+static const char* kLocaleColumnName = "locale";
+
+NS_IMPL_ADDREF(nsDBFolderInfo)
+NS_IMPL_RELEASE(nsDBFolderInfo)
+
+NS_IMETHODIMP
+nsDBFolderInfo::QueryInterface(REFNSIID iid, void** result) {
+  if (!result) return NS_ERROR_NULL_POINTER;
+
+  *result = nullptr;
+  if (iid.Equals(NS_GET_IID(nsIDBFolderInfo)) ||
+      iid.Equals(NS_GET_IID(nsISupports))) {
+    *result = static_cast<nsIDBFolderInfo*>(this);
+    AddRef();
+    return NS_OK;
+  }
+  return NS_NOINTERFACE;
+}
+
+nsDBFolderInfo::nsDBFolderInfo(nsMsgDatabase* mdb)
+    : m_flags(0),
+      m_expiredMark(0),
+      m_tableKindToken(0),
+      m_expiredMarkColumnToken(0) {
+  m_mdbTable = NULL;
+  m_mdbRow = NULL;
+  m_version = 1;                 // for upgrading...
+  m_IMAPHierarchySeparator = 0;  // imap path separator
+  // mail only (for now)
+  m_folderSize = 0;
+  m_folderDate = 0;
+  m_expungedBytes = 0;  // sum of size of deleted messages in folder
+  m_highWaterMessageKey = 0;
+
+  m_numUnreadMessages = 0;
+  m_numMessages = 0;
+  // IMAP only
+  m_ImapUidValidity = kUidUnknown;
+  m_totalPendingMessages = 0;
+  m_unreadPendingMessages = 0;
+
+  m_mdbTokensInitialized = false;
+
+  m_mdb = mdb;
+  if (mdb) {
+    nsresult err;
+
+    err = m_mdb->GetStore()->StringToToken(mdb->GetEnv(), kDBFolderInfoScope,
+                                           &m_rowScopeToken);
+    if (NS_SUCCEEDED(err)) {
+      err = m_mdb->GetStore()->StringToToken(
+          mdb->GetEnv(), kDBFolderInfoTableKind, &m_tableKindToken);
+      if (NS_SUCCEEDED(err)) {
+        gDBFolderInfoOID.mOid_Scope = m_rowScopeToken;
+        gDBFolderInfoOID.mOid_Id = 1;
+      }
+    }
+    InitMDBInfo();
+  }
+}
+
+nsDBFolderInfo::~nsDBFolderInfo() {
+  // nsMsgDatabase strictly owns nsDBFolderInfo, so don't ref-count db.
+  ReleaseExternalReferences();
+}
+
+// Release any objects we're holding onto. This needs to be safe
+// to call multiple times.
+void nsDBFolderInfo::ReleaseExternalReferences() {
+  if (m_mdb) {
+    if (m_mdbTable) {
+      NS_RELEASE(m_mdbTable);
+      m_mdbTable = nullptr;
+    }
+    if (m_mdbRow) {
+      NS_RELEASE(m_mdbRow);
+      m_mdbRow = nullptr;
+    }
+    m_mdb = nullptr;
+  }
+}
+
+// this routine sets up a new db to know about the dbFolderInfo stuff...
+nsresult nsDBFolderInfo::AddToNewMDB() {
+  nsresult ret = NS_OK;
+  if (m_mdb && m_mdb->GetStore()) {
+    nsIMdbStore* store = m_mdb->GetStore();
+    // create the unique table for the dbFolderInfo.
+    nsresult err =
+        store->NewTable(m_mdb->GetEnv(), m_rowScopeToken, m_tableKindToken,
+                        true, nullptr, &m_mdbTable);
+
+    // create the singleton row for the dbFolderInfo.
+    err = store->NewRowWithOid(m_mdb->GetEnv(), &gDBFolderInfoOID, &m_mdbRow);
+
+    // add the row to the singleton table.
+    if (m_mdbRow && NS_SUCCEEDED(err))
+      err = m_mdbTable->AddRow(m_mdb->GetEnv(), m_mdbRow);
+
+    ret = err;  // what are we going to do about nsresult's?
+  }
+  return ret;
+}
+
+nsresult nsDBFolderInfo::InitFromExistingDB() {
+  nsresult ret = NS_OK;
+  if (m_mdb && m_mdb->GetStore()) {
+    nsIMdbStore* store = m_mdb->GetStore();
+    if (store) {
+      mdb_pos rowPos;
+      mdb_count outTableCount;  // current number of such tables
+      mdb_bool mustBeUnique;    // whether port can hold only one of these
+      mdb_bool hasOid;
+      ret = store->GetTableKind(m_mdb->GetEnv(), m_rowScopeToken,
+                                m_tableKindToken, &outTableCount, &mustBeUnique,
+                                &m_mdbTable);
+      // NS_ASSERTION(mustBeUnique && outTableCount == 1, "only one global db
+      // info allowed");
+
+      if (m_mdbTable) {
+        // find singleton row for global info.
+        ret = m_mdbTable->HasOid(m_mdb->GetEnv(), &gDBFolderInfoOID, &hasOid);
+        if (NS_SUCCEEDED(ret)) {
+          nsIMdbTableRowCursor* rowCursor;
+          rowPos = -1;
+          ret = m_mdbTable->GetTableRowCursor(m_mdb->GetEnv(), rowPos,
+                                              &rowCursor);
+          if (NS_SUCCEEDED(ret)) {
+            ret = rowCursor->NextRow(m_mdb->GetEnv(), &m_mdbRow, &rowPos);
+            NS_RELEASE(rowCursor);
+            if (!m_mdbRow) ret = NS_ERROR_FAILURE;
+            if (NS_SUCCEEDED(ret)) LoadMemberVariables();
+          }
+        }
+      } else
+        ret = NS_ERROR_FAILURE;
+    }
+  }
+  return ret;
+}
+
+nsresult nsDBFolderInfo::InitMDBInfo() {
+  nsresult ret = NS_OK;
+  if (!m_mdbTokensInitialized && m_mdb && m_mdb->GetStore()) {
+    nsIMdbStore* store = m_mdb->GetStore();
+    nsIMdbEnv* env = m_mdb->GetEnv();
+
+    store->StringToToken(env, kNumMessagesColumnName,
+                         &m_numMessagesColumnToken);
+    store->StringToToken(env, kNumUnreadMessagesColumnName,
+                         &m_numUnreadMessagesColumnToken);
+    store->StringToToken(env, kFlagsColumnName, &m_flagsColumnToken);
+    store->StringToToken(env, kFolderSizeColumnName, &m_folderSizeColumnToken);
+    store->StringToToken(env, kExpungedBytesColumnName,
+                         &m_expungedBytesColumnToken);
+    store->StringToToken(env, kFolderDateColumnName, &m_folderDateColumnToken);
+
+    store->StringToToken(env, kHighWaterMessageKeyColumnName,
+                         &m_highWaterMessageKeyColumnToken);
+    store->StringToToken(env, kMailboxNameColumnName,
+                         &m_mailboxNameColumnToken);
+
+    store->StringToToken(env, kImapUidValidityColumnName,
+                         &m_imapUidValidityColumnToken);
+    store->StringToToken(env, kTotalPendingMessagesColumnName,
+                         &m_totalPendingMessagesColumnToken);
+    store->StringToToken(env, kUnreadPendingMessagesColumnName,
+                         &m_unreadPendingMessagesColumnToken);
+    store->StringToToken(env, kExpiredMarkColumnName,
+                         &m_expiredMarkColumnToken);
+    store->StringToToken(env, kVersionColumnName, &m_versionColumnToken);
+    m_mdbTokensInitialized = true;
+  }
+
+  return ret;
+}
+
+nsresult nsDBFolderInfo::LoadMemberVariables() {
+  // it's really not an error for these properties to not exist...
+  GetInt32PropertyWithToken(m_numMessagesColumnToken, m_numMessages);
+  GetInt32PropertyWithToken(m_numUnreadMessagesColumnToken,
+                            m_numUnreadMessages);
+  GetInt32PropertyWithToken(m_flagsColumnToken, m_flags);
+  GetInt64PropertyWithToken(m_folderSizeColumnToken, m_folderSize);
+  GetUint32PropertyWithToken(m_folderDateColumnToken, m_folderDate);
+  GetInt32PropertyWithToken(m_imapUidValidityColumnToken, m_ImapUidValidity,
+                            kUidUnknown);
+  GetUint32PropertyWithToken(m_expiredMarkColumnToken, m_expiredMark);
+  GetInt64PropertyWithToken(m_expungedBytesColumnToken, m_expungedBytes);
+  GetUint32PropertyWithToken(m_highWaterMessageKeyColumnToken,
+                             m_highWaterMessageKey);
+  int32_t version;
+
+  GetInt32PropertyWithToken(m_versionColumnToken, version);
+  m_version = (uint16_t)version;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetVersion(uint32_t version) {
+  m_version = version;
+  return SetUint32PropertyWithToken(m_versionColumnToken, (uint32_t)m_version);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetVersion(uint32_t* version) {
+  *version = m_version;
+  return NS_OK;
+}
+
+nsresult nsDBFolderInfo::AdjustHighWater(nsMsgKey highWater, bool force) {
+  if (force || m_highWaterMessageKey < highWater) {
+    m_highWaterMessageKey = highWater;
+    SetUint32PropertyWithToken(m_highWaterMessageKeyColumnToken, highWater);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetHighWater(nsMsgKey highWater) {
+  return AdjustHighWater(highWater, true);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::OnKeyAdded(nsMsgKey aNewKey) {
+  return AdjustHighWater(aNewKey, false);
+}
+
+NS_IMETHODIMP
+nsDBFolderInfo::GetFolderSize(int64_t* size) {
+  NS_ENSURE_ARG_POINTER(size);
+  *size = m_folderSize;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetFolderSize(int64_t size) {
+  m_folderSize = size;
+  return SetInt64Property(kFolderSizeColumnName, m_folderSize);
+}
+
+NS_IMETHODIMP
+nsDBFolderInfo::GetFolderDate(uint32_t* folderDate) {
+  NS_ENSURE_ARG_POINTER(folderDate);
+  *folderDate = m_folderDate;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetFolderDate(uint32_t folderDate) {
+  m_folderDate = folderDate;
+  return SetUint32PropertyWithToken(m_folderDateColumnToken, folderDate);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetHighWater(nsMsgKey* result) {
+  // Sanity check highwater - if it gets too big, other code
+  // can fail. Look through last 100 messages to recalculate
+  // the highwater mark.
+  *result = m_highWaterMessageKey;
+  if (m_highWaterMessageKey > 0xFFFFFF00 && m_mdb) {
+    nsCOMPtr<nsIMsgEnumerator> hdrs;
+    nsresult rv = m_mdb->ReverseEnumerateMessages(getter_AddRefs(hdrs));
+    if (NS_FAILED(rv)) return rv;
+    bool hasMore = false;
+    nsCOMPtr<nsIMsgDBHdr> pHeader;
+    nsMsgKey recalculatedHighWater = 1;
+    int32_t i = 0;
+    while (i++ < 100 && NS_SUCCEEDED(rv = hdrs->HasMoreElements(&hasMore)) &&
+           hasMore) {
+      (void)hdrs->GetNext(getter_AddRefs(pHeader));
+      if (pHeader) {
+        nsMsgKey msgKey;
+        pHeader->GetMessageKey(&msgKey);
+        if (msgKey > recalculatedHighWater) recalculatedHighWater = msgKey;
+      }
+    }
+    NS_ASSERTION(m_highWaterMessageKey >= recalculatedHighWater,
+                 "highwater incorrect");
+    m_highWaterMessageKey = recalculatedHighWater;
+  }
+  *result = m_highWaterMessageKey;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetExpiredMark(nsMsgKey expiredKey) {
+  m_expiredMark = expiredKey;
+  return SetUint32PropertyWithToken(m_expiredMarkColumnToken, expiredKey);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetExpiredMark(nsMsgKey* result) {
+  *result = m_expiredMark;
+  return NS_OK;
+}
+
+// The size of the argument depends on the maximum size of a single message
+NS_IMETHODIMP nsDBFolderInfo::ChangeExpungedBytes(int32_t delta) {
+  return SetExpungedBytes(m_expungedBytes + delta);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetMailboxName(const nsAString& newBoxName) {
+  return SetPropertyWithToken(m_mailboxNameColumnToken, newBoxName);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetMailboxName(nsAString& boxName) {
+  return GetPropertyWithToken(m_mailboxNameColumnToken, boxName);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::ChangeNumUnreadMessages(int32_t delta) {
+  m_numUnreadMessages += delta;
+  // m_numUnreadMessages can never be set to negative.
+  if (m_numUnreadMessages < 0) {
+#ifdef DEBUG_bienvenu1
+    NS_ASSERTION(false, "Hardcoded assertion");
+#endif
+    m_numUnreadMessages = 0;
+  }
+  return SetUint32PropertyWithToken(m_numUnreadMessagesColumnToken,
+                                    m_numUnreadMessages);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::ChangeNumMessages(int32_t delta) {
+  m_numMessages += delta;
+  // m_numMessages can never be set to negative.
+  if (m_numMessages < 0) {
+#ifdef DEBUG_bienvenu
+    NS_ASSERTION(false, "num messages can't be < 0");
+#endif
+    m_numMessages = 0;
+  }
+  return SetUint32PropertyWithToken(m_numMessagesColumnToken, m_numMessages);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetNumUnreadMessages(int32_t* result) {
+  *result = m_numUnreadMessages;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetNumUnreadMessages(int32_t numUnreadMessages) {
+  m_numUnreadMessages = numUnreadMessages;
+  return SetUint32PropertyWithToken(m_numUnreadMessagesColumnToken,
+                                    m_numUnreadMessages);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetNumMessages(int32_t* result) {
+  *result = m_numMessages;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetNumMessages(int32_t numMessages) {
+  m_numMessages = numMessages;
+  return SetUint32PropertyWithToken(m_numMessagesColumnToken, m_numMessages);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetExpungedBytes(int64_t* result) {
+  *result = m_expungedBytes;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetExpungedBytes(int64_t expungedBytes) {
+  m_expungedBytes = expungedBytes;
+  return SetInt64PropertyWithToken(m_expungedBytesColumnToken, m_expungedBytes);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetFlags(int32_t* result) {
+  *result = m_flags;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetFlags(int32_t flags) {
+  nsresult ret = NS_OK;
+
+  if (m_flags != flags) {
+    NS_ASSERTION((m_flags & nsMsgFolderFlags::Inbox) == 0 ||
+                     (flags & nsMsgFolderFlags::Inbox) != 0,
+                 "lost inbox flag");
+    m_flags = flags;
+    ret = SetInt32PropertyWithToken(m_flagsColumnToken, m_flags);
+  }
+  return ret;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::OrFlags(int32_t flags, int32_t* result) {
+  m_flags |= flags;
+  *result = m_flags;
+  return SetInt32PropertyWithToken(m_flagsColumnToken, m_flags);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::AndFlags(int32_t flags, int32_t* result) {
+  m_flags &= flags;
+  *result = m_flags;
+  return SetInt32PropertyWithToken(m_flagsColumnToken, m_flags);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetImapUidValidity(int32_t* result) {
+  *result = m_ImapUidValidity;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetImapUidValidity(int32_t uidValidity) {
+  m_ImapUidValidity = uidValidity;
+  return SetUint32PropertyWithToken(m_imapUidValidityColumnToken,
+                                    m_ImapUidValidity);
+}
+
+bool nsDBFolderInfo::TestFlag(int32_t flags) { return (m_flags & flags) != 0; }
+
+NS_IMETHODIMP
+nsDBFolderInfo::GetLocale(nsAString& result) {
+  GetProperty(kLocaleColumnName, result);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetLocale(const nsAString& locale) {
+  return SetProperty(kLocaleColumnName, locale);
+}
+
+NS_IMETHODIMP
+nsDBFolderInfo::GetImapTotalPendingMessages(int32_t* result) {
+  NS_ENSURE_ARG_POINTER(result);
+  *result = m_totalPendingMessages;
+  return NS_OK;
+}
+
+void nsDBFolderInfo::ChangeImapTotalPendingMessages(int32_t delta) {
+  m_totalPendingMessages += delta;
+  SetInt32PropertyWithToken(m_totalPendingMessagesColumnToken,
+                            m_totalPendingMessages);
+}
+
+NS_IMETHODIMP
+nsDBFolderInfo::GetImapUnreadPendingMessages(int32_t* result) {
+  NS_ENSURE_ARG_POINTER(result);
+  *result = m_unreadPendingMessages;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetImapUnreadPendingMessages(
+    int32_t numUnreadPendingMessages) {
+  m_unreadPendingMessages = numUnreadPendingMessages;
+  return SetUint32PropertyWithToken(m_unreadPendingMessagesColumnToken,
+                                    m_unreadPendingMessages);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetImapTotalPendingMessages(
+    int32_t numTotalPendingMessages) {
+  m_totalPendingMessages = numTotalPendingMessages;
+  return SetUint32PropertyWithToken(m_totalPendingMessagesColumnToken,
+                                    m_totalPendingMessages);
+}
+
+void nsDBFolderInfo::ChangeImapUnreadPendingMessages(int32_t delta) {
+  m_unreadPendingMessages += delta;
+  SetInt32PropertyWithToken(m_unreadPendingMessagesColumnToken,
+                            m_unreadPendingMessages);
+}
+
+/* attribute nsMsgViewTypeValue viewType; */
+NS_IMETHODIMP nsDBFolderInfo::GetViewType(nsMsgViewTypeValue* aViewType) {
+  uint32_t viewTypeValue;
+  nsresult rv = GetUint32Property("viewType", nsMsgViewType::eShowAllThreads,
+                                  &viewTypeValue);
+  *aViewType = viewTypeValue;
+  return rv;
+}
+NS_IMETHODIMP nsDBFolderInfo::SetViewType(nsMsgViewTypeValue aViewType) {
+  return SetUint32Property("viewType", aViewType);
+}
+
+/* attribute nsMsgViewFlagsTypeValue viewFlags; */
+NS_IMETHODIMP nsDBFolderInfo::GetViewFlags(
+    nsMsgViewFlagsTypeValue* aViewFlags) {
+  nsMsgViewFlagsTypeValue defaultViewFlags;
+  nsresult rv = m_mdb->GetDefaultViewFlags(&defaultViewFlags);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  uint32_t viewFlagsValue;
+  rv = GetUint32Property("viewFlags", defaultViewFlags, &viewFlagsValue);
+  *aViewFlags = viewFlagsValue;
+  return rv;
+}
+NS_IMETHODIMP nsDBFolderInfo::SetViewFlags(nsMsgViewFlagsTypeValue aViewFlags) {
+  return SetUint32Property("viewFlags", aViewFlags);
+}
+
+/* attribute nsMsgViewSortTypeValue sortType; */
+NS_IMETHODIMP nsDBFolderInfo::GetSortType(nsMsgViewSortTypeValue* aSortType) {
+  nsMsgViewSortTypeValue defaultSortType;
+  nsresult rv = m_mdb->GetDefaultSortType(&defaultSortType);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  uint32_t sortTypeValue;
+  rv = GetUint32Property("sortType", defaultSortType, &sortTypeValue);
+  *aSortType = sortTypeValue;
+  return rv;
+}
+NS_IMETHODIMP nsDBFolderInfo::SetSortType(nsMsgViewSortTypeValue aSortType) {
+  return SetUint32Property("sortType", aSortType);
+}
+
+/* attribute nsMsgViewSortOrderValue sortOrder; */
+NS_IMETHODIMP nsDBFolderInfo::GetSortOrder(
+    nsMsgViewSortOrderValue* aSortOrder) {
+  nsMsgViewSortOrderValue defaultSortOrder;
+  nsresult rv = m_mdb->GetDefaultSortOrder(&defaultSortOrder);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  uint32_t sortOrderValue;
+  rv = GetUint32Property("sortOrder", defaultSortOrder, &sortOrderValue);
+  *aSortOrder = sortOrderValue;
+  return rv;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetSortOrder(nsMsgViewSortOrderValue aSortOrder) {
+  return SetUint32Property("sortOrder", aSortOrder);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetKnownArtsSet(const char* newsArtSet) {
+  return m_mdb->SetProperty(m_mdbRow, kKnownArtsSetColumnName, newsArtSet);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetKnownArtsSet(char** newsArtSet) {
+  return m_mdb->GetProperty(m_mdbRow, kKnownArtsSetColumnName, newsArtSet);
+}
+
+// get arbitrary property, aka row cell value.
+NS_IMETHODIMP nsDBFolderInfo::GetProperty(const char* propertyName,
+                                          nsAString& resultProperty) {
+  return m_mdb->GetPropertyAsNSString(m_mdbRow, propertyName, resultProperty);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetCharProperty(
+    const char* aPropertyName, const nsACString& aPropertyValue) {
+  return m_mdb->SetProperty(m_mdbRow, aPropertyName,
+                            PromiseFlatCString(aPropertyValue).get());
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetCharProperty(const char* propertyName,
+                                              nsACString& resultProperty) {
+  nsCString result;
+  nsresult rv =
+      m_mdb->GetProperty(m_mdbRow, propertyName, getter_Copies(result));
+  if (NS_SUCCEEDED(rv)) resultProperty.Assign(result);
+  return rv;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetUint32Property(const char* propertyName,
+                                                uint32_t propertyValue) {
+  return m_mdb->SetUint32Property(m_mdbRow, propertyName, propertyValue);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetInt64Property(const char* propertyName,
+                                               int64_t propertyValue) {
+  return m_mdb->SetUint64Property(m_mdbRow, propertyName,
+                                  (uint64_t)propertyValue);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetProperty(const char* propertyName,
+                                          const nsAString& propertyStr) {
+  return m_mdb->SetPropertyFromNSString(m_mdbRow, propertyName, propertyStr);
+}
+
+nsresult nsDBFolderInfo::SetPropertyWithToken(mdb_token aProperty,
+                                              const nsAString& propertyStr) {
+  return m_mdb->SetNSStringPropertyWithToken(m_mdbRow, aProperty, propertyStr);
+}
+
+nsresult nsDBFolderInfo::SetUint32PropertyWithToken(mdb_token aProperty,
+                                                    uint32_t propertyValue) {
+  return m_mdb->UInt32ToRowCellColumn(m_mdbRow, aProperty, propertyValue);
+}
+
+nsresult nsDBFolderInfo::SetInt64PropertyWithToken(mdb_token aProperty,
+                                                   int64_t propertyValue) {
+  return m_mdb->UInt64ToRowCellColumn(m_mdbRow, aProperty,
+                                      (uint64_t)propertyValue);
+}
+
+nsresult nsDBFolderInfo::SetInt32PropertyWithToken(mdb_token aProperty,
+                                                   int32_t propertyValue) {
+  nsAutoString propertyStr;
+  propertyStr.AppendInt(propertyValue, 16);
+  return SetPropertyWithToken(aProperty, propertyStr);
+}
+
+nsresult nsDBFolderInfo::GetPropertyWithToken(mdb_token aProperty,
+                                              nsAString& resultProperty) {
+  return m_mdb->RowCellColumnTonsString(m_mdbRow, aProperty, resultProperty);
+}
+
+nsresult nsDBFolderInfo::GetUint32PropertyWithToken(mdb_token aProperty,
+                                                    uint32_t& propertyValue,
+                                                    uint32_t defaultValue) {
+  return m_mdb->RowCellColumnToUInt32(m_mdbRow, aProperty, propertyValue,
+                                      defaultValue);
+}
+
+nsresult nsDBFolderInfo::GetInt32PropertyWithToken(mdb_token aProperty,
+                                                   int32_t& propertyValue,
+                                                   int32_t defaultValue) {
+  return m_mdb->RowCellColumnToUInt32(m_mdbRow, aProperty,
+                                      (uint32_t&)propertyValue, defaultValue);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetUint32Property(const char* propertyName,
+                                                uint32_t defaultValue,
+                                                uint32_t* propertyValue) {
+  return m_mdb->GetUint32Property(m_mdbRow, propertyName, propertyValue,
+                                  defaultValue);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetInt64Property(const char* propertyName,
+                                               int64_t defaultValue,
+                                               int64_t* propertyValue) {
+  return m_mdb->GetUint64Property(m_mdbRow, propertyName,
+                                  (uint64_t*)&propertyValue, defaultValue);
+}
+
+nsresult nsDBFolderInfo::GetInt64PropertyWithToken(mdb_token aProperty,
+                                                   int64_t& propertyValue,
+                                                   int64_t defaultValue) {
+  return m_mdb->RowCellColumnToUInt64(m_mdbRow, aProperty,
+                                      (uint64_t*)&propertyValue, defaultValue);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetBooleanProperty(const char* propertyName,
+                                                 bool defaultValue,
+                                                 bool* propertyValue) {
+  uint32_t defaultUint32Value = (defaultValue) ? 1 : 0;
+  uint32_t returnValue;
+  nsresult rv = m_mdb->GetUint32Property(m_mdbRow, propertyName, &returnValue,
+                                         defaultUint32Value);
+  *propertyValue = (returnValue != 0);
+  return rv;
+}
+NS_IMETHODIMP nsDBFolderInfo::SetBooleanProperty(const char* propertyName,
+                                                 bool propertyValue) {
+  return m_mdb->SetUint32Property(m_mdbRow, propertyName,
+                                  propertyValue ? 1 : 0);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetFolderName(nsACString& folderName) {
+  return GetCharProperty("folderName", folderName);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetFolderName(const nsACString& folderName) {
+  return SetCharProperty("folderName", folderName);
+}
+
+class nsTransferDBFolderInfo : public nsDBFolderInfo {
+ public:
+  nsTransferDBFolderInfo();
+  virtual ~nsTransferDBFolderInfo();
+  // parallel arrays of properties and values
+  nsTArray<nsCString> m_properties;
+  nsTArray<nsCString> m_values;
+};
+
+nsTransferDBFolderInfo::nsTransferDBFolderInfo() : nsDBFolderInfo(nullptr) {}
+
+nsTransferDBFolderInfo::~nsTransferDBFolderInfo() {}
+
+/* void GetTransferInfo (out nsIDBFolderInfo transferInfo); */
+NS_IMETHODIMP nsDBFolderInfo::GetTransferInfo(nsIDBFolderInfo** transferInfo) {
+  NS_ENSURE_ARG_POINTER(transferInfo);
+  NS_ENSURE_STATE(m_mdbRow);
+
+  RefPtr<nsTransferDBFolderInfo> newInfo = new nsTransferDBFolderInfo;
+
+  mdb_count numCells;
+  mdbYarn cellYarn;
+  mdb_column cellColumn;
+  char columnName[100];
+  mdbYarn cellName = {columnName, 0, sizeof(columnName), 0, 0, nullptr};
+
+  m_mdbRow->GetCount(m_mdb->GetEnv(), &numCells);
+  // iterate over the cells in the dbfolderinfo remembering attribute names and
+  // values.
+  for (mdb_count cellIndex = 0; cellIndex < numCells; cellIndex++) {
+    nsresult err = m_mdbRow->SeekCellYarn(m_mdb->GetEnv(), cellIndex,
+                                          &cellColumn, nullptr);
+    if (NS_SUCCEEDED(err)) {
+      err = m_mdbRow->AliasCellYarn(m_mdb->GetEnv(), cellColumn, &cellYarn);
+      if (NS_SUCCEEDED(err)) {
+        m_mdb->GetStore()->TokenToString(m_mdb->GetEnv(), cellColumn,
+                                         &cellName);
+        newInfo->m_values.AppendElement(
+            Substring((const char*)cellYarn.mYarn_Buf,
+                      (const char*)cellYarn.mYarn_Buf + cellYarn.mYarn_Fill));
+        newInfo->m_properties.AppendElement(
+            Substring((const char*)cellName.mYarn_Buf,
+                      (const char*)cellName.mYarn_Buf + cellName.mYarn_Fill));
+      }
+    }
+  }
+
+  newInfo.forget(transferInfo);
+  return NS_OK;
+}
+
+/* void InitFromTransferInfo (in nsIDBFolderInfo transferInfo); */
+NS_IMETHODIMP nsDBFolderInfo::InitFromTransferInfo(
+    nsIDBFolderInfo* aTransferInfo) {
+  NS_ENSURE_ARG(aTransferInfo);
+
+  nsTransferDBFolderInfo* transferInfo =
+      static_cast<nsTransferDBFolderInfo*>(aTransferInfo);
+
+  for (uint32_t i = 0; i < transferInfo->m_values.Length(); i++)
+    SetCharProperty(transferInfo->m_properties[i].get(),
+                    transferInfo->m_values[i]);
+
+  LoadMemberVariables();
+  return NS_OK;
+}
diff --git a/comm/mailnews/db/msgdb/src/nsImapMailDatabase.cpp b/comm/mailnews/db/msgdb/src/nsImapMailDatabase.cpp
new file mode 100644
index 0000000000..7103d0c475
--- /dev/null
+++ b/comm/mailnews/db/msgdb/src/nsImapMailDatabase.cpp
@@ -0,0 +1,217 @@
+/* -*- 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 <sys/stat.h>
+
+#include "msgCore.h"
+#include "nsImapMailDatabase.h"
+#include "nsDBFolderInfo.h"
+#include "nsMsgMessageFlags.h"
+
+const char* kPendingHdrsScope =
+    "ns:msg:db:row:scope:pending:all";  // scope for all offine ops table
+const char* kPendingHdrsTableKind = "ns:msg:db:table:kind:pending";
+struct mdbOid gAllPendingHdrsTableOID;
+
+nsImapMailDatabase::nsImapMailDatabase()
+    : m_pendingHdrsRowScopeToken(0), m_pendingHdrsTableKindToken(0) {}
+
+nsImapMailDatabase::~nsImapMailDatabase() {}
+
+NS_IMETHODIMP nsImapMailDatabase::GetSummaryValid(bool* aResult) {
+  NS_ENSURE_ARG_POINTER(aResult);
+  if (m_dbFolderInfo) {
+    uint32_t version;
+    m_dbFolderInfo->GetVersion(&version);
+    *aResult = (GetCurVersion() == version);
+  } else
+    *aResult = false;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsImapMailDatabase::SetSummaryValid(bool valid) {
+  if (m_dbFolderInfo) {
+    m_dbFolderInfo->SetVersion(valid ? GetCurVersion() : 0);
+    Commit(nsMsgDBCommitType::kLargeCommit);
+  }
+  return NS_OK;
+}
+
+// We override this to avoid our parent class (nsMailDatabase)'s
+// grabbing of the folder semaphore, and bailing on failure.
+NS_IMETHODIMP nsImapMailDatabase::DeleteMessages(
+    nsTArray<nsMsgKey> const& nsMsgKeys, nsIDBChangeListener* instigator) {
+  return nsMsgDatabase::DeleteMessages(nsMsgKeys, instigator);
+}
+
+nsresult nsImapMailDatabase::AdjustExpungedBytesOnDelete(nsIMsgDBHdr* msgHdr) {
+  uint32_t msgFlags;
+  msgHdr->GetFlags(&msgFlags);
+  if (msgFlags & nsMsgMessageFlags::Offline && m_dbFolderInfo) {
+    uint32_t size = 0;
+    (void)msgHdr->GetOfflineMessageSize(&size);
+    return m_dbFolderInfo->ChangeExpungedBytes(size);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsImapMailDatabase::ForceClosed() {
+  m_mdbAllPendingHdrsTable = nullptr;
+  return nsMailDatabase::ForceClosed();
+}
+
+nsresult nsImapMailDatabase::GetAllPendingHdrsTable() {
+  nsresult rv = NS_OK;
+  if (!m_mdbAllPendingHdrsTable)
+    rv = GetTableCreateIfMissing(kPendingHdrsScope, kPendingHdrsTableKind,
+                                 getter_AddRefs(m_mdbAllPendingHdrsTable),
+                                 m_pendingHdrsRowScopeToken,
+                                 m_pendingHdrsTableKindToken);
+  return rv;
+}
+
+NS_IMETHODIMP nsImapMailDatabase::AddNewHdrToDB(nsIMsgDBHdr* newHdr,
+                                                bool notify) {
+  nsresult rv = nsMsgDatabase::AddNewHdrToDB(newHdr, notify);
+  if (NS_SUCCEEDED(rv)) rv = UpdatePendingAttributes(newHdr);
+  return rv;
+}
+
+NS_IMETHODIMP nsImapMailDatabase::UpdatePendingAttributes(
+    nsIMsgDBHdr* aNewHdr) {
+  nsresult rv = GetAllPendingHdrsTable();
+  NS_ENSURE_SUCCESS(rv, rv);
+  mdb_count numPendingHdrs = 0;
+  m_mdbAllPendingHdrsTable->GetCount(GetEnv(), &numPendingHdrs);
+  if (numPendingHdrs > 0) {
+    mdbYarn messageIdYarn;
+    nsCOMPtr<nsIMdbRow> pendingRow;
+    mdbOid outRowId;
+
+    nsCString messageId;
+    aNewHdr->GetMessageId(getter_Copies(messageId));
+    messageIdYarn.mYarn_Buf = (void*)messageId.get();
+    messageIdYarn.mYarn_Fill = messageId.Length();
+    messageIdYarn.mYarn_Form = 0;
+    messageIdYarn.mYarn_Size = messageIdYarn.mYarn_Fill;
+
+    m_mdbStore->FindRow(GetEnv(), m_pendingHdrsRowScopeToken,
+                        m_messageIdColumnToken, &messageIdYarn, &outRowId,
+                        getter_AddRefs(pendingRow));
+    if (pendingRow) {
+      mdb_count numCells;
+      mdbYarn cellYarn;
+      mdb_column cellColumn;
+      uint32_t existingFlags;
+
+      pendingRow->GetCount(GetEnv(), &numCells);
+      aNewHdr->GetFlags(&existingFlags);
+      // iterate over the cells in the pending hdr setting properties on the
+      // aNewHdr. we skip cell 0, which is the messageId;
+      nsMsgHdr* msgHdr =
+          static_cast<nsMsgHdr*>(aNewHdr);  // closed system, cast ok
+      nsIMdbRow* row = msgHdr->GetMDBRow();
+      for (mdb_count cellIndex = 1; cellIndex < numCells; cellIndex++) {
+        nsresult err =
+            pendingRow->SeekCellYarn(GetEnv(), cellIndex, &cellColumn, nullptr);
+        if (NS_SUCCEEDED(err)) {
+          err = pendingRow->AliasCellYarn(GetEnv(), cellColumn, &cellYarn);
+          if (NS_SUCCEEDED(err)) {
+            if (row) row->AddColumn(GetEnv(), cellColumn, &cellYarn);
+          }
+        }
+      }
+      // We might have changed some cached values, so force a refresh.
+      msgHdr->ClearCachedValues();
+      uint32_t resultFlags;
+      msgHdr->OrFlags(existingFlags, &resultFlags);
+      m_mdbAllPendingHdrsTable->CutRow(GetEnv(), pendingRow);
+      pendingRow->CutAllColumns(GetEnv());
+    }
+  }
+  return rv;
+}
+
+nsresult nsImapMailDatabase::GetRowForPendingHdr(nsIMsgDBHdr* pendingHdr,
+                                                 nsIMdbRow** row) {
+  nsresult rv = GetAllPendingHdrsTable();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  mdbYarn messageIdYarn;
+  nsCOMPtr<nsIMdbRow> pendingRow;
+  mdbOid outRowId;
+  nsCString messageId;
+  pendingHdr->GetMessageId(getter_Copies(messageId));
+  messageIdYarn.mYarn_Buf = (void*)messageId.get();
+  messageIdYarn.mYarn_Fill = messageId.Length();
+  messageIdYarn.mYarn_Form = 0;
+  messageIdYarn.mYarn_Size = messageIdYarn.mYarn_Fill;
+
+  rv = m_mdbStore->FindRow(GetEnv(), m_pendingHdrsRowScopeToken,
+                           m_messageIdColumnToken, &messageIdYarn, &outRowId,
+                           getter_AddRefs(pendingRow));
+
+  if (!pendingRow)
+    rv = m_mdbStore->NewRow(GetEnv(), m_pendingHdrsRowScopeToken,
+                            getter_AddRefs(pendingRow));
+
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (pendingRow) {
+    // now we need to add cells to the row to remember the messageid, property
+    // and property value, and flags. Then, when hdrs are added to the db, we'll
+    // check if they have a matching message-id, and if so, set the property and
+    // flags
+    // XXX we already fetched messageId from the pending hdr, could it have
+    // changed by the time we get here?
+    nsCString messageId;
+    pendingHdr->GetMessageId(getter_Copies(messageId));
+    // we're just going to ignore messages without a message-id. They should be
+    // rare. If SPAM messages often didn't have message-id's, they'd be filtered
+    // on the server, most likely, and spammers would then start putting in
+    // message-id's.
+    if (!messageId.IsEmpty()) {
+      extern const char* kMessageIdColumnName;
+      m_mdbAllPendingHdrsTable->AddRow(GetEnv(), pendingRow);
+      // make sure this is the first cell so that when we ignore the first
+      // cell in nsImapMailDatabase::AddNewHdrToDB, we're ignoring the right one
+      (void)SetProperty(pendingRow, kMessageIdColumnName, messageId.get());
+      pendingRow.forget(row);
+    } else
+      return NS_ERROR_FAILURE;
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsImapMailDatabase::SetAttributeOnPendingHdr(
+    nsIMsgDBHdr* pendingHdr, const char* property, const char* propertyVal) {
+  NS_ENSURE_ARG_POINTER(pendingHdr);
+  nsCOMPtr<nsIMdbRow> pendingRow;
+  nsresult rv = GetRowForPendingHdr(pendingHdr, getter_AddRefs(pendingRow));
+  NS_ENSURE_SUCCESS(rv, rv);
+  return SetProperty(pendingRow, property, propertyVal);
+}
+
+NS_IMETHODIMP
+nsImapMailDatabase::SetUint32AttributeOnPendingHdr(nsIMsgDBHdr* pendingHdr,
+                                                   const char* property,
+                                                   uint32_t propertyVal) {
+  NS_ENSURE_ARG_POINTER(pendingHdr);
+  nsCOMPtr<nsIMdbRow> pendingRow;
+  nsresult rv = GetRowForPendingHdr(pendingHdr, getter_AddRefs(pendingRow));
+  NS_ENSURE_SUCCESS(rv, rv);
+  return SetUint32Property(pendingRow, property, propertyVal);
+}
+
+NS_IMETHODIMP
+nsImapMailDatabase::SetUint64AttributeOnPendingHdr(nsIMsgDBHdr* aPendingHdr,
+                                                   const char* aProperty,
+                                                   uint64_t aPropertyVal) {
+  NS_ENSURE_ARG_POINTER(aPendingHdr);
+  nsCOMPtr<nsIMdbRow> pendingRow;
+  nsresult rv = GetRowForPendingHdr(aPendingHdr, getter_AddRefs(pendingRow));
+  NS_ENSURE_SUCCESS(rv, rv);
+  return SetUint64Property(pendingRow, aProperty, aPropertyVal);
+}
diff --git a/comm/mailnews/db/msgdb/src/nsMailDatabase.cpp b/comm/mailnews/db/msgdb/src/nsMailDatabase.cpp
new file mode 100644
index 0000000000..c07294785a
--- /dev/null
+++ b/comm/mailnews/db/msgdb/src/nsMailDatabase.cpp
@@ -0,0 +1,380 @@
+/* -*- 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 "msgCore.h"
+#include "nsMailDatabase.h"
+#include "nsDBFolderInfo.h"
+#include "nsMsgLocalFolderHdrs.h"
+#include "nsNetUtil.h"
+#include "nsMsgOfflineImapOperation.h"
+#include "nsMsgFolderFlags.h"
+#include "mozilla/Logging.h"
+#include "prprf.h"
+#include "nsMsgUtils.h"
+#include "nsIMsgPluggableStore.h"
+#include "nsSimpleEnumerator.h"
+
+using namespace mozilla;
+
+extern LazyLogModule IMAPOffline;  // defined in nsMsgOfflineImapOperation.cpp
+
+// scope for all offine ops table
+const char* kOfflineOpsScope = "ns:msg:db:row:scope:ops:all";
+const char* kOfflineOpsTableKind = "ns:msg:db:table:kind:ops";
+struct mdbOid gAllOfflineOpsTableOID;
+
+nsMailDatabase::nsMailDatabase() : m_reparse(false) {
+  m_mdbAllOfflineOpsTable = nullptr;
+  m_offlineOpsRowScopeToken = 0;
+  m_offlineOpsTableKindToken = 0;
+}
+
+nsMailDatabase::~nsMailDatabase() {}
+
+// caller passes in upgrading==true if they want back a db even if the db is out
+// of date. If so, they'll extract out the interesting info from the db, close
+// it, delete it, and then try to open the db again, prior to reparsing.
+nsresult nsMailDatabase::Open(nsMsgDBService* aDBService, nsIFile* aSummaryFile,
+                              bool aCreate, bool aUpgrading) {
+#ifdef DEBUG
+  nsString leafName;
+  aSummaryFile->GetLeafName(leafName);
+  if (!StringEndsWith(leafName, NS_LITERAL_STRING_FROM_CSTRING(SUMMARY_SUFFIX),
+                      nsCaseInsensitiveStringComparator))
+    NS_ERROR("non summary file passed into open");
+#endif
+  return nsMsgDatabase::Open(aDBService, aSummaryFile, aCreate, aUpgrading);
+}
+
+NS_IMETHODIMP nsMailDatabase::ForceClosed() {
+  m_mdbAllOfflineOpsTable = nullptr;
+  return nsMsgDatabase::ForceClosed();
+}
+
+// get this on demand so that only db's that have offline ops will
+// create the table.
+nsresult nsMailDatabase::GetAllOfflineOpsTable() {
+  nsresult rv = NS_OK;
+  if (!m_mdbAllOfflineOpsTable)
+    rv = GetTableCreateIfMissing(kOfflineOpsScope, kOfflineOpsTableKind,
+                                 getter_AddRefs(m_mdbAllOfflineOpsTable),
+                                 m_offlineOpsRowScopeToken,
+                                 m_offlineOpsTableKindToken);
+  return rv;
+}
+
+NS_IMETHODIMP nsMailDatabase::DeleteMessages(
+    nsTArray<nsMsgKey> const& nsMsgKeys, nsIDBChangeListener* instigator) {
+  nsresult rv;
+  if (m_folder) {
+    bool isLocked;
+    m_folder->GetLocked(&isLocked);
+    if (isLocked) {
+      NS_ASSERTION(false, "Some other operation is in progress");
+      return NS_MSG_FOLDER_BUSY;
+    }
+  }
+
+  rv = nsMsgDatabase::DeleteMessages(nsMsgKeys, instigator);
+  SetSummaryValid(true);
+  return rv;
+}
+
+NS_IMETHODIMP nsMailDatabase::GetSummaryValid(bool* aResult) {
+  uint32_t version;
+  m_dbFolderInfo->GetVersion(&version);
+  if (GetCurVersion() != version) {
+    *aResult = false;
+    return NS_OK;
+  }
+  if (!m_folder) {
+    // If the folder is not set, we just return without checking the validity
+    // of the summary file. For now, this is an expected condition when the
+    // message database is being opened from a URL in
+    // nsMailboxUrl::GetMsgHdrForKey() which calls
+    // nsMsgDBService::OpenMailDBFromFile() without a folder.
+    // Returning an error here would lead to the deletion of the MSF in the
+    // caller nsMsgDatabase::CheckForErrors().
+    *aResult = true;
+    return NS_OK;
+  }
+
+  // If this is a virtual folder, there is no storage.
+  bool isVirtual = false;
+  m_folder->GetFlag(nsMsgFolderFlags::Virtual, &isVirtual);
+  if (isVirtual) {
+    *aResult = true;
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIMsgPluggableStore> msgStore;
+  nsresult rv = m_folder->GetMsgStore(getter_AddRefs(msgStore));
+  NS_ENSURE_SUCCESS(rv, rv);
+  return msgStore->IsSummaryFileValid(m_folder, this, aResult);
+}
+
+NS_IMETHODIMP nsMailDatabase::SetSummaryValid(bool aValid) {
+  nsMsgDatabase::SetSummaryValid(aValid);
+
+  if (!m_folder) return NS_ERROR_NULL_POINTER;
+
+  // If this is a virtual folder, there is no storage.
+  bool flag;
+  m_folder->GetFlag(nsMsgFolderFlags::Virtual, &flag);
+  if (flag) return NS_OK;
+
+  nsCOMPtr<nsIMsgPluggableStore> msgStore;
+  nsresult rv = m_folder->GetMsgStore(getter_AddRefs(msgStore));
+  NS_ENSURE_SUCCESS(rv, rv);
+  return msgStore->SetSummaryFileValid(m_folder, this, aValid);
+}
+
+NS_IMETHODIMP nsMailDatabase::RemoveOfflineOp(nsIMsgOfflineImapOperation* op) {
+  nsresult rv = GetAllOfflineOpsTable();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (!op || !m_mdbAllOfflineOpsTable) return NS_ERROR_NULL_POINTER;
+  nsMsgOfflineImapOperation* offlineOp =
+      static_cast<nsMsgOfflineImapOperation*>(
+          op);  // closed system, so this is ok
+  nsIMdbRow* row = offlineOp->GetMDBRow();
+  rv = m_mdbAllOfflineOpsTable->CutRow(GetEnv(), row);
+  row->CutAllColumns(GetEnv());
+  return rv;
+}
+
+NS_IMETHODIMP nsMailDatabase::GetOfflineOpForKey(
+    nsMsgKey msgKey, bool create, nsIMsgOfflineImapOperation** offlineOp) {
+  mdb_bool hasOid;
+  mdbOid rowObjectId;
+  nsresult err;
+
+  nsresult rv = GetAllOfflineOpsTable();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (!offlineOp || !m_mdbAllOfflineOpsTable) return NS_ERROR_NULL_POINTER;
+
+  *offlineOp = NULL;
+
+  rowObjectId.mOid_Id = msgKey;
+  rowObjectId.mOid_Scope = m_offlineOpsRowScopeToken;
+  err = m_mdbAllOfflineOpsTable->HasOid(GetEnv(), &rowObjectId, &hasOid);
+  if (NS_SUCCEEDED(err) && m_mdbStore && (hasOid || create)) {
+    nsCOMPtr<nsIMdbRow> offlineOpRow;
+    err = m_mdbStore->GetRow(GetEnv(), &rowObjectId,
+                             getter_AddRefs(offlineOpRow));
+
+    if (create) {
+      if (!offlineOpRow) {
+        err = m_mdbStore->NewRowWithOid(GetEnv(), &rowObjectId,
+                                        getter_AddRefs(offlineOpRow));
+        NS_ENSURE_SUCCESS(err, err);
+      }
+      if (offlineOpRow && !hasOid)
+        m_mdbAllOfflineOpsTable->AddRow(GetEnv(), offlineOpRow);
+    }
+
+    if (NS_SUCCEEDED(err) && offlineOpRow) {
+      NS_IF_ADDREF(*offlineOp =
+                       new nsMsgOfflineImapOperation(this, offlineOpRow));
+      (*offlineOp)->SetMessageKey(msgKey);
+    }
+    if (!hasOid && m_dbFolderInfo) {
+      // set initial value for flags so we don't lose them.
+      nsCOMPtr<nsIMsgDBHdr> msgHdr;
+      GetMsgHdrForKey(msgKey, getter_AddRefs(msgHdr));
+      if (msgHdr) {
+        uint32_t flags;
+        msgHdr->GetFlags(&flags);
+        (*offlineOp)->SetNewFlags(flags);
+      }
+      int32_t newFlags;
+      m_dbFolderInfo->OrFlags(nsMsgFolderFlags::OfflineEvents, &newFlags);
+    }
+  }
+
+  return err;
+}
+
+NS_IMETHODIMP nsMailDatabase::ListAllOfflineOpIds(
+    nsTArray<nsMsgKey>& offlineOpIds) {
+  nsresult rv = GetAllOfflineOpsTable();
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsIMdbTableRowCursor* rowCursor;
+
+  if (m_mdbAllOfflineOpsTable) {
+    nsresult err =
+        m_mdbAllOfflineOpsTable->GetTableRowCursor(GetEnv(), -1, &rowCursor);
+    while (NS_SUCCEEDED(err) && rowCursor) {
+      mdbOid outOid;
+      mdb_pos outPos;
+
+      err = rowCursor->NextRowOid(GetEnv(), &outOid, &outPos);
+      // is this right? Mork is returning a 0 id, but that should valid.
+      if (outPos < 0 || outOid.mOid_Id == (mdb_id)-1) break;
+      if (NS_SUCCEEDED(err)) {
+        offlineOpIds.AppendElement(outOid.mOid_Id);
+        if (MOZ_LOG_TEST(IMAPOffline, LogLevel::Info)) {
+          nsCOMPtr<nsIMsgOfflineImapOperation> offlineOp;
+          GetOfflineOpForKey(outOid.mOid_Id, false, getter_AddRefs(offlineOp));
+          if (offlineOp) {
+            nsMsgOfflineImapOperation* logOp =
+                static_cast<nsMsgOfflineImapOperation*>(
+                    static_cast<nsIMsgOfflineImapOperation*>(offlineOp.get()));
+            if (logOp) logOp->Log();
+          }
+        }
+      }
+    }
+    // TODO: would it cause a problem to replace this with "rv = err;" ?
+    rv = (NS_SUCCEEDED(err)) ? NS_OK : NS_ERROR_FAILURE;
+    rowCursor->Release();
+  }
+
+  offlineOpIds.Sort();
+  return rv;
+}
+
+NS_IMETHODIMP nsMailDatabase::ListAllOfflineDeletes(
+    nsTArray<nsMsgKey>& offlineDeletes) {
+  nsresult rv = GetAllOfflineOpsTable();
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsIMdbTableRowCursor* rowCursor;
+  if (m_mdbAllOfflineOpsTable) {
+    nsresult err =
+        m_mdbAllOfflineOpsTable->GetTableRowCursor(GetEnv(), -1, &rowCursor);
+    while (NS_SUCCEEDED(err) && rowCursor) {
+      mdbOid outOid;
+      mdb_pos outPos;
+      nsIMdbRow* offlineOpRow;
+
+      err = rowCursor->NextRow(GetEnv(), &offlineOpRow, &outPos);
+      // is this right? Mork is returning a 0 id, but that should valid.
+      if (outPos < 0 || offlineOpRow == nullptr) break;
+      if (NS_SUCCEEDED(err)) {
+        offlineOpRow->GetOid(GetEnv(), &outOid);
+        RefPtr<nsIMsgOfflineImapOperation> offlineOp =
+            new nsMsgOfflineImapOperation(this, offlineOpRow);
+        imapMessageFlagsType newFlags;
+        nsOfflineImapOperationType opType;
+
+        offlineOp->GetOperation(&opType);
+        offlineOp->GetNewFlags(&newFlags);
+        if (opType & nsIMsgOfflineImapOperation::kMsgMoved ||
+            ((opType & nsIMsgOfflineImapOperation::kFlagsChanged) &&
+             (newFlags & nsIMsgOfflineImapOperation::kMsgMarkedDeleted)))
+          offlineDeletes.AppendElement(outOid.mOid_Id);
+
+        offlineOpRow->Release();
+      }
+    }
+    // TODO: would it cause a problem to replace this with "rv = err;" ?
+    rv = (NS_SUCCEEDED(err)) ? NS_OK : NS_ERROR_FAILURE;
+    rowCursor->Release();
+  }
+  return rv;
+}
+
+// This is used to remember that the db is out of sync with the mail folder
+// and needs to be regenerated.
+void nsMailDatabase::SetReparse(bool reparse) { m_reparse = reparse; }
+
+class nsMsgOfflineOpEnumerator : public nsSimpleEnumerator {
+ public:
+  const nsID& DefaultInterface() override {
+    return NS_GET_IID(nsIMsgOfflineImapOperation);
+  }
+
+  // nsISimpleEnumerator methods:
+  NS_DECL_NSISIMPLEENUMERATOR
+
+  explicit nsMsgOfflineOpEnumerator(nsMailDatabase* db);
+
+ protected:
+  ~nsMsgOfflineOpEnumerator() override;
+  nsresult GetRowCursor();
+  nsresult PrefetchNext();
+  nsMailDatabase* mDB;
+  nsIMdbTableRowCursor* mRowCursor;
+  nsCOMPtr<nsIMsgOfflineImapOperation> mResultOp;
+  bool mDone;
+  bool mNextPrefetched;
+};
+
+nsMsgOfflineOpEnumerator::nsMsgOfflineOpEnumerator(nsMailDatabase* db)
+    : mDB(db), mRowCursor(nullptr), mDone(false) {
+  NS_ADDREF(mDB);
+  mNextPrefetched = false;
+}
+
+nsMsgOfflineOpEnumerator::~nsMsgOfflineOpEnumerator() {
+  NS_IF_RELEASE(mRowCursor);
+  NS_RELEASE(mDB);
+}
+
+nsresult nsMsgOfflineOpEnumerator::GetRowCursor() {
+  nsresult rv = NS_OK;
+  mDone = false;
+
+  if (!mDB || !mDB->m_mdbAllOfflineOpsTable) return NS_ERROR_NULL_POINTER;
+
+  rv = mDB->m_mdbAllOfflineOpsTable->GetTableRowCursor(mDB->GetEnv(), -1,
+                                                       &mRowCursor);
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgOfflineOpEnumerator::GetNext(nsISupports** aItem) {
+  NS_ENSURE_ARG_POINTER(aItem);
+
+  nsresult rv = NS_OK;
+  if (!mNextPrefetched) rv = PrefetchNext();
+  if (NS_SUCCEEDED(rv)) {
+    if (mResultOp) {
+      NS_ADDREF(*aItem = mResultOp);
+      mNextPrefetched = false;
+    }
+  }
+  return rv;
+}
+
+nsresult nsMsgOfflineOpEnumerator::PrefetchNext() {
+  nsresult rv = NS_OK;
+  nsIMdbRow* offlineOpRow;
+  mdb_pos rowPos;
+
+  if (!mRowCursor) {
+    rv = GetRowCursor();
+    if (NS_FAILED(rv)) return rv;
+  }
+
+  rv = mRowCursor->NextRow(mDB->GetEnv(), &offlineOpRow, &rowPos);
+  if (!offlineOpRow) {
+    mDone = true;
+    return NS_ERROR_FAILURE;
+  }
+  if (NS_FAILED(rv)) {
+    mDone = true;
+    return rv;
+  }
+
+  nsIMsgOfflineImapOperation* op =
+      new nsMsgOfflineImapOperation(mDB, offlineOpRow);
+  mResultOp = op;
+  if (!op) return NS_ERROR_OUT_OF_MEMORY;
+
+  if (mResultOp) {
+    mNextPrefetched = true;
+    return NS_OK;
+  }
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP nsMsgOfflineOpEnumerator::HasMoreElements(bool* aResult) {
+  NS_ENSURE_ARG_POINTER(aResult);
+
+  if (!mNextPrefetched) PrefetchNext();
+  *aResult = !mDone;
+  return NS_OK;
+}
diff --git a/comm/mailnews/db/msgdb/src/nsMsgDatabase.cpp b/comm/mailnews/db/msgdb/src/nsMsgDatabase.cpp
new file mode 100644
index 0000000000..779ca400a9
--- /dev/null
+++ b/comm/mailnews/db/msgdb/src/nsMsgDatabase.cpp
@@ -0,0 +1,4730 @@
+/* -*- 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/. */
+
+// this file implements the nsMsgDatabase interface using the MDB Interface.
+
+#include "nscore.h"
+#include "msgCore.h"
+#include "nsIFile.h"
+#include "nsMailDatabase.h"
+#include "nsDBFolderInfo.h"
+#include "nsIMsgNewsFolder.h"
+#include "nsMsgThread.h"
+#include "nsIMsgSearchTerm.h"
+#include "nsIMdbFactoryFactory.h"
+#include "mozilla/Logging.h"
+#include "mozilla/Telemetry.h"
+#include "prprf.h"
+#include "nsMsgFolderFlags.h"
+#include "nsIMsgAccountManager.h"
+#include "nsIMsgDBView.h"
+#include "nsIMsgFolderCache.h"
+#include "nsIMsgFolderCacheElement.h"
+#include "MailNewsTypes2.h"
+#include "nsMsgUtils.h"
+#include "nsComponentManagerUtils.h"
+#include "nsServiceManagerUtils.h"
+#include "nsMemory.h"
+#include "nsIPrefService.h"
+#include "nsIPrefBranch.h"
+#include "nsPrintfCString.h"
+#include "nsMsgDatabaseEnumerators.h"
+#include "nsIMemoryReporter.h"
+#include "nsIWeakReferenceUtils.h"
+#include "nsMailDirServiceDefs.h"
+#include "mozilla/Components.h"
+#include "mozilla/mailnews/MimeHeaderParser.h"
+#include "mozilla/intl/LocaleService.h"
+
+using namespace mozilla::mailnews;
+using namespace mozilla;
+
+#if defined(DEBUG_sspitzer_) || defined(DEBUG_seth_)
+#  define DEBUG_MSGKEYSET 1
+#endif
+
+#define MSG_HASH_SIZE 512
+
+// This will be used on discovery, since we don't know total.
+const int32_t kMaxHdrsInCache = 512;
+
+// special keys
+static const nsMsgKey kAllMsgHdrsTableKey = 1;
+static const nsMsgKey kTableKeyForThreadOne = 0xfffffffe;
+static const nsMsgKey kAllThreadsTableKey = 0xfffffffd;
+static const nsMsgKey kFirstPseudoKey = 0xfffffff0;
+static const nsMsgKey kIdStartOfFake = 0xffffff80;
+static const nsMsgKey kForceReparseKey = 0xfffffff0;
+
+LazyLogModule DBLog("MsgDB");
+
+PRTime nsMsgDatabase::gLastUseTime;
+
+/**
+ * mozilla::intl APIs require sizeable buffers. This class abstracts over
+ * the nsTArray.
+ */
+class nsTArrayU8Buffer {
+ public:
+  using CharType = uint8_t;
+
+  // Do not allow copy or move. Move could be added in the future if needed.
+  nsTArrayU8Buffer(const nsTArrayU8Buffer&) = delete;
+  nsTArrayU8Buffer& operator=(const nsTArrayU8Buffer&) = delete;
+
+  explicit nsTArrayU8Buffer(nsTArray<CharType>& aArray) : mArray(aArray) {}
+
+  /**
+   * Ensures the buffer has enough space to accommodate |size| elements.
+   */
+  [[nodiscard]] bool reserve(size_t size) {
+    mArray.SetCapacity(size);
+    // nsTArray::SetCapacity returns void, return true to keep the API the same
+    // as the other Buffer implementations.
+    return true;
+  }
+
+  /**
+   * Returns the raw data inside the buffer.
+   */
+  CharType* data() { return mArray.Elements(); }
+
+  /**
+   * Returns the count of elements written into the buffer.
+   */
+  size_t length() const { return mArray.Length(); }
+
+  /**
+   * Returns the buffer's overall capacity.
+   */
+  size_t capacity() const { return mArray.Capacity(); }
+
+  /**
+   * Resizes the buffer to the given amount of written elements.
+   */
+  void written(size_t amount) {
+    MOZ_ASSERT(amount <= mArray.Capacity());
+    // This sets |mArray|'s internal size so that it matches how much was
+    // written. This is necessary because the write happens across FFI
+    // boundaries.
+    mArray.SetLengthAndRetainStorage(amount);
+  }
+
+ private:
+  nsTArray<CharType>& mArray;
+};
+
+NS_IMPL_ISUPPORTS(nsMsgDBService, nsIMsgDBService)
+
+nsMsgDBService::nsMsgDBService() {}
+
+nsMsgDBService::~nsMsgDBService() {
+#ifdef DEBUG
+  // If you hit this warning, it means that some code is holding onto
+  // a db at shutdown.
+  NS_WARNING_ASSERTION(!m_dbCache.Length(), "some msg dbs left open");
+#  ifndef MOZILLA_OFFICIAL
+  // Only print this on local builds since it causes crashes,
+  // see bug 1468691, bug 1377692 and bug 1342858.
+  for (uint32_t i = 0; i < m_dbCache.Length(); i++) {
+    nsMsgDatabase* pMessageDB = m_dbCache.ElementAt(i);
+    if (pMessageDB)
+      printf("db left open %s\n",
+             pMessageDB->m_dbFile->HumanReadablePath().get());
+  }
+#  endif
+#endif
+}
+
+NS_IMETHODIMP nsMsgDBService::OpenFolderDB(nsIMsgFolder* aFolder,
+                                           bool aLeaveInvalidDB,
+                                           nsIMsgDatabase** _retval) {
+  NS_ENSURE_ARG(aFolder);
+  nsCOMPtr<nsIMsgIncomingServer> incomingServer;
+  nsresult rv = aFolder->GetServer(getter_AddRefs(incomingServer));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIFile> summaryFilePath;
+  rv = aFolder->GetSummaryFile(getter_AddRefs(summaryFilePath));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsMsgDatabase* cacheDB = FindInCache(summaryFilePath);
+  if (cacheDB) {
+    // this db could have ended up in the folder cache w/o an m_folder pointer
+    // via OpenMailDBFromFile. If so, take this chance to fix the folder.
+    if (!cacheDB->m_folder) cacheDB->m_folder = aFolder;
+    cacheDB->RememberLastUseTime();
+    *_retval = cacheDB;  // FindInCache already addRefed.
+    // if m_thumb is set, someone is asynchronously opening the db. But our
+    // caller wants to synchronously open it, so just do it.
+    if (cacheDB->m_thumb)
+      return cacheDB->Open(this, summaryFilePath, false, aLeaveInvalidDB);
+    return NS_OK;
+  }
+
+  nsCString localDatabaseType;
+  incomingServer->GetLocalDatabaseType(localDatabaseType);
+  nsAutoCString dbContractID("@mozilla.org/nsMsgDatabase/msgDB-");
+  dbContractID.Append(localDatabaseType.get());
+  nsCOMPtr<nsIMsgDatabase> msgDB = do_CreateInstance(dbContractID.get(), &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Don't try to create the database yet--let the createNewDB call do that.
+  nsMsgDatabase* msgDatabase = static_cast<nsMsgDatabase*>(msgDB.get());
+  msgDatabase->m_folder = aFolder;
+  rv = msgDatabase->Open(this, summaryFilePath, false, aLeaveInvalidDB);
+  if (NS_FAILED(rv) && rv != NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE) return rv;
+
+  NS_ADDREF(*_retval = msgDB);
+
+  if (NS_FAILED(rv)) {
+#ifdef DEBUG
+    // Doing these checks for debug only as we don't want to report certain
+    // errors in debug mode, but in release mode we wouldn't report them either
+
+    // These errors are expected.
+    if (rv == NS_MSG_ERROR_FOLDER_SUMMARY_MISSING ||
+        rv == NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE)
+      return rv;
+
+    // If it isn't one of the expected errors, throw a warning.
+    NS_ENSURE_SUCCESS(rv, rv);
+#endif
+    return rv;
+  }
+
+  FinishDBOpen(aFolder, msgDatabase);
+  return rv;
+}
+
+/**
+ * When a db is opened, we need to hook up any pending listeners for
+ * that db, and notify them.
+ */
+void nsMsgDBService::HookupPendingListeners(nsIMsgDatabase* db,
+                                            nsIMsgFolder* folder) {
+  for (int32_t listenerIndex = 0;
+       listenerIndex < m_foldersPendingListeners.Count(); listenerIndex++) {
+    //  check if we have a pending listener on this db, and if so, add it.
+    if (m_foldersPendingListeners[listenerIndex] == folder) {
+      db->AddListener(m_pendingListeners.ObjectAt(listenerIndex));
+      m_pendingListeners.ObjectAt(listenerIndex)->OnEvent(db, "DBOpened");
+    }
+  }
+}
+
+void nsMsgDBService::FinishDBOpen(nsIMsgFolder* aFolder,
+                                  nsMsgDatabase* aMsgDB) {
+  uint32_t folderFlags;
+  aFolder->GetFlags(&folderFlags);
+
+  if (!(folderFlags & nsMsgFolderFlags::Virtual) &&
+      aMsgDB->m_mdbAllMsgHeadersTable) {
+    mdb_count numHdrsInTable = 0;
+    int32_t numMessages;
+    aMsgDB->m_mdbAllMsgHeadersTable->GetCount(aMsgDB->GetEnv(),
+                                              &numHdrsInTable);
+    aMsgDB->m_dbFolderInfo->GetNumMessages(&numMessages);
+    if (numMessages != (int32_t)numHdrsInTable) aMsgDB->SyncCounts();
+  }
+  HookupPendingListeners(aMsgDB, aFolder);
+  aMsgDB->RememberLastUseTime();
+}
+
+//----------------------------------------------------------------------
+// FindInCache - this addrefs the db it finds.
+//----------------------------------------------------------------------
+nsMsgDatabase* nsMsgDBService::FindInCache(nsIFile* dbName) {
+  for (uint32_t i = 0; i < m_dbCache.Length(); i++) {
+    nsMsgDatabase* pMessageDB = m_dbCache[i];
+    if (pMessageDB->MatchDbName(dbName)) {
+      if (pMessageDB->m_mdbStore)  // don't return db without store
+      {
+        NS_ADDREF(pMessageDB);
+        return pMessageDB;
+      }
+    }
+  }
+  return nullptr;
+}
+
+// This method is called when the caller is trying to create a db without
+// having a corresponding nsIMsgFolder object.  This happens in a few
+// situations, including imap folder discovery, compacting local folders,
+// and copying local folders.
+NS_IMETHODIMP nsMsgDBService::OpenMailDBFromFile(nsIFile* aFolderName,
+                                                 nsIMsgFolder* aFolder,
+                                                 bool aCreate,
+                                                 bool aLeaveInvalidDB,
+                                                 nsIMsgDatabase** pMessageDB) {
+  if (!aFolderName) return NS_ERROR_NULL_POINTER;
+
+  nsCOMPtr<nsIFile> dbPath;
+  nsresult rv = GetSummaryFileLocation(aFolderName, getter_AddRefs(dbPath));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  *pMessageDB = FindInCache(dbPath);
+  if (*pMessageDB) return NS_OK;
+
+  RefPtr<nsMailDatabase> msgDB = new nsMailDatabase;
+  NS_ENSURE_TRUE(msgDB, NS_ERROR_OUT_OF_MEMORY);
+  rv = msgDB->Open(this, dbPath, aCreate, aLeaveInvalidDB);
+  if (rv == NS_ERROR_FILE_NOT_FOUND) return rv;
+  NS_IF_ADDREF(*pMessageDB = msgDB);
+  if (aCreate && msgDB && rv == NS_MSG_ERROR_FOLDER_SUMMARY_MISSING) rv = NS_OK;
+  if (NS_SUCCEEDED(rv)) msgDB->m_folder = aFolder;
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgDBService::CreateNewDB(nsIMsgFolder* aFolder,
+                                          nsIMsgDatabase** _retval) {
+  NS_ENSURE_ARG(aFolder);
+
+  nsCOMPtr<nsIMsgIncomingServer> incomingServer;
+  nsresult rv = aFolder->GetServer(getter_AddRefs(incomingServer));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIFile> summaryFilePath;
+  rv = aFolder->GetSummaryFile(getter_AddRefs(summaryFilePath));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCString localDatabaseType;
+  incomingServer->GetLocalDatabaseType(localDatabaseType);
+  nsAutoCString dbContractID("@mozilla.org/nsMsgDatabase/msgDB-");
+  dbContractID.Append(localDatabaseType.get());
+
+  nsCOMPtr<nsIMsgDatabase> msgDB = do_CreateInstance(dbContractID.get(), &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsMsgDatabase* msgDatabase = static_cast<nsMsgDatabase*>(msgDB.get());
+
+  msgDatabase->m_folder = aFolder;
+  rv = msgDatabase->Open(this, summaryFilePath, true, true);
+
+  // We are trying to create a new database, but that implies that it did not
+  // already exist. Open returns NS_MSG_ERROR_FOLDER_SUMMARY_MISSING for the
+  // successful creation of a new database. But if it existed for some
+  // reason, then we would get rv = NS_OK instead. That is a "failure"
+  // from our perspective, so we want to return a failure since we are not
+  // returning a valid database object.
+  NS_ENSURE_TRUE(rv == NS_MSG_ERROR_FOLDER_SUMMARY_MISSING,
+                 NS_SUCCEEDED(rv) ? NS_ERROR_FILE_ALREADY_EXISTS : rv);
+
+  NS_ADDREF(*_retval = msgDB);
+
+  HookupPendingListeners(msgDB, aFolder);
+
+  msgDatabase->RememberLastUseTime();
+
+  return NS_OK;
+}
+
+/* void registerPendingListener (in nsIMsgFolder aFolder, in nsIDBChangeListener
+ * aListener); */
+NS_IMETHODIMP nsMsgDBService::RegisterPendingListener(
+    nsIMsgFolder* aFolder, nsIDBChangeListener* aListener) {
+  // need to make sure we don't hold onto these forever. Maybe a shutdown
+  // listener? if there is a db open on this folder already, we should register
+  // the listener.
+  m_foldersPendingListeners.AppendObject(aFolder);
+  m_pendingListeners.AppendObject(aListener);
+  nsCOMPtr<nsIMsgDatabase> openDB;
+  CachedDBForFolder(aFolder, getter_AddRefs(openDB));
+  if (openDB) openDB->AddListener(aListener);
+  return NS_OK;
+}
+
+/* void unregisterPendingListener (in nsIDBChangeListener aListener); */
+NS_IMETHODIMP nsMsgDBService::UnregisterPendingListener(
+    nsIDBChangeListener* aListener) {
+  int32_t listenerIndex = m_pendingListeners.IndexOfObject(aListener);
+  if (listenerIndex != -1) {
+    nsCOMPtr<nsIMsgDatabase> msgDB;
+    CachedDBForFolder(m_foldersPendingListeners[listenerIndex],
+                      getter_AddRefs(msgDB));
+    if (msgDB) msgDB->RemoveListener(aListener);
+    m_foldersPendingListeners.RemoveObjectAt(listenerIndex);
+    m_pendingListeners.RemoveObjectAt(listenerIndex);
+    return NS_OK;
+  }
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP nsMsgDBService::CachedDBForFolder(nsIMsgFolder* aFolder,
+                                                nsIMsgDatabase** aRetDB) {
+  NS_ENSURE_ARG_POINTER(aFolder);
+  NS_ENSURE_ARG_POINTER(aRetDB);
+
+  nsCOMPtr<nsIFile> summaryFilePath;
+  nsresult rv = aFolder->GetSummaryFile(getter_AddRefs(summaryFilePath));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  *aRetDB = FindInCache(summaryFilePath);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDBService::ForceFolderDBClosed(nsIMsgFolder* aFolder) {
+  nsCOMPtr<nsIMsgDatabase> mailDB;
+  nsresult rv = CachedDBForFolder(aFolder, getter_AddRefs(mailDB));
+  if (mailDB) {
+    mailDB->ForceClosed();
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgDBService::GetOpenDBs(
+    nsTArray<RefPtr<nsIMsgDatabase>>& aOpenDBs) {
+  aOpenDBs.Clear();
+  aOpenDBs.SetCapacity(m_dbCache.Length());
+  for (auto db : m_dbCache) {
+    aOpenDBs.AppendElement(db);
+  }
+  return NS_OK;
+}
+
+static bool gGotGlobalPrefs = false;
+static bool gThreadWithoutRe = true;
+static bool gStrictThreading = false;
+static bool gCorrectThreading = false;
+
+void nsMsgDatabase::GetGlobalPrefs() {
+  if (!gGotGlobalPrefs) {
+    GetBoolPref("mail.thread_without_re", &gThreadWithoutRe);
+    GetBoolPref("mail.strict_threading", &gStrictThreading);
+    GetBoolPref("mail.correct_threading", &gCorrectThreading);
+    gGotGlobalPrefs = true;
+  }
+}
+
+nsresult nsMsgDatabase::AddHdrToCache(
+    nsIMsgDBHdr* hdr, nsMsgKey key)  // do we want key? We could get it from hdr
+{
+  if (m_bCacheHeaders) {
+    if (!m_cachedHeaders)
+      m_cachedHeaders = new PLDHashTable(
+          &gMsgDBHashTableOps, sizeof(struct MsgHdrHashElement), m_cacheSize);
+    if (m_cachedHeaders) {
+      if (key == nsMsgKey_None) hdr->GetMessageKey(&key);
+      if (m_cachedHeaders->EntryCount() > m_cacheSize) ClearHdrCache(true);
+      PLDHashEntryHdr* entry =
+          m_cachedHeaders->Add((void*)(uintptr_t)key, mozilla::fallible);
+      if (!entry) return NS_ERROR_OUT_OF_MEMORY;  // XXX out of memory
+
+      MsgHdrHashElement* element = static_cast<MsgHdrHashElement*>(entry);
+      element->mHdr = hdr;
+      element->mKey = key;
+      NS_ADDREF(hdr);  // make the cache hold onto the header
+      return NS_OK;
+    }
+  }
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP nsMsgDatabase::SetMsgHdrCacheSize(uint32_t aSize) {
+  m_cacheSize = aSize;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetMsgHdrCacheSize(uint32_t* aSize) {
+  NS_ENSURE_ARG_POINTER(aSize);
+  *aSize = m_cacheSize;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetLastUseTime(PRTime* aTime) {
+  NS_ENSURE_ARG_POINTER(aTime);
+  *aTime = m_lastUseTime;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::SetLastUseTime(PRTime aTime) {
+  gLastUseTime = m_lastUseTime = aTime;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetDatabaseSize(int64_t* _retval) {
+  NS_ENSURE_ARG_POINTER(_retval);
+
+  nsresult rv;
+  bool exists;
+  NS_ENSURE_TRUE(m_dbFile, NS_ERROR_NULL_POINTER);
+  rv = m_dbFile->Exists(&exists);
+  if (NS_SUCCEEDED(rv)) {
+    if (exists)
+      rv = m_dbFile->GetFileSize(_retval);
+    else
+      *_retval = 0;
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgDatabase::ClearCachedHdrs() {
+  ClearCachedObjects(false);
+#ifdef DEBUG_bienvenu1
+  if (mRefCnt > 1) {
+    NS_ASSERTION(false, "");
+    printf("someone's holding onto db - refs = %ld\n", mRefCnt);
+  }
+#endif
+  return NS_OK;
+}
+
+// Invalidate any outstanding message enumerators using this db.
+void nsMsgDatabase::InvalidateEnumerators() {
+  RefPtr<nsMsgDatabase> kungFuDeathGrip(this);
+  // Work in reverse, as the enumerators remove themselves from the list.
+  {
+    auto n = m_msgEnumerators.Length();
+    for (auto i = n; i > 0; --i) {
+      m_msgEnumerators[i - 1]->Invalidate();
+    }
+  }
+  // And again for thread enumerators.
+  {
+    auto n = m_threadEnumerators.Length();
+    for (auto i = n; i > 0; --i) {
+      m_threadEnumerators[i - 1]->Invalidate();
+    }
+  }
+}
+
+nsMsgThread* nsMsgDatabase::FindExistingThread(nsMsgKey threadId) {
+  uint32_t numThreads = m_threads.Length();
+  for (uint32_t i = 0; i < numThreads; i++)
+    if (m_threads[i]->m_threadKey == threadId) return m_threads[i];
+
+  return nullptr;
+}
+
+void nsMsgDatabase::ClearThreads() {
+  // clear out existing threads
+  nsTArray<nsMsgThread*> copyThreads;
+  copyThreads.SwapElements(m_threads);
+
+  uint32_t numThreads = copyThreads.Length();
+  for (uint32_t i = 0; i < numThreads; i++) copyThreads[i]->Clear();
+}
+
+void nsMsgDatabase::ClearCachedObjects(bool dbGoingAway) {
+  ClearHdrCache(false);
+#ifdef DEBUG_DavidBienvenu
+  if (m_headersInUse && m_headersInUse->EntryCount() > 0) {
+    NS_ASSERTION(false, "leaking headers");
+    printf("leaking %d headers in %s\n", m_headersInUse->EntryCount(),
+           m_dbFile->HumanReadablePath().get());
+  }
+#endif
+  m_cachedThread = nullptr;
+  m_cachedThreadId = nsMsgKey_None;
+  // We should only clear the use hdr cache when the db is going away, or we
+  // could end up with multiple copies of the same logical msg hdr, which will
+  // lead to ref-counting problems.
+  if (dbGoingAway) {
+    ClearUseHdrCache();
+    ClearThreads();
+  }
+  m_thumb = nullptr;
+}
+
+nsresult nsMsgDatabase::ClearHdrCache(bool reInit) {
+  if (m_cachedHeaders) {
+    // save this away in case we renter this code.
+    PLDHashTable* saveCachedHeaders = m_cachedHeaders;
+    m_cachedHeaders = nullptr;
+    for (auto iter = saveCachedHeaders->Iter(); !iter.Done(); iter.Next()) {
+      auto element = static_cast<MsgHdrHashElement*>(iter.Get());
+      if (element) NS_IF_RELEASE(element->mHdr);
+    }
+
+    if (reInit) {
+      saveCachedHeaders->ClearAndPrepareForLength(m_cacheSize);
+      m_cachedHeaders = saveCachedHeaders;
+    } else {
+      delete saveCachedHeaders;
+    }
+  }
+  return NS_OK;
+}
+
+nsresult nsMsgDatabase::RemoveHdrFromCache(nsIMsgDBHdr* hdr, nsMsgKey key) {
+  if (m_cachedHeaders) {
+    if (key == nsMsgKey_None) hdr->GetMessageKey(&key);
+
+    PLDHashEntryHdr* entry =
+        m_cachedHeaders->Search((const void*)(uintptr_t)key);
+    if (entry) {
+      m_cachedHeaders->Remove((void*)(uintptr_t)key);
+      NS_RELEASE(hdr);  // get rid of extra ref the cache was holding.
+    }
+  }
+  return NS_OK;
+}
+
+nsresult nsMsgDatabase::GetHdrFromUseCache(nsMsgKey key, nsIMsgDBHdr** result) {
+  if (!result) return NS_ERROR_NULL_POINTER;
+
+  nsresult rv = NS_ERROR_FAILURE;
+
+  *result = nullptr;
+
+  if (m_headersInUse) {
+    PLDHashEntryHdr* entry =
+        m_headersInUse->Search((const void*)(uintptr_t)key);
+    if (entry) {
+      MsgHdrHashElement* element = static_cast<MsgHdrHashElement*>(entry);
+      *result = element->mHdr;
+    }
+    if (*result) {
+      NS_ADDREF(*result);
+      rv = NS_OK;
+    }
+  }
+  return rv;
+}
+
+PLDHashTableOps nsMsgDatabase::gMsgDBHashTableOps = {
+    HashKey, MatchEntry, MoveEntry, ClearEntry, nullptr};
+
+// HashKey is supposed to maximize entropy in the low order bits, and the key
+// as is, should do that.
+PLDHashNumber nsMsgDatabase::HashKey(const void* aKey) {
+  return PLDHashNumber(NS_PTR_TO_INT32(aKey));
+}
+
+bool nsMsgDatabase::MatchEntry(const PLDHashEntryHdr* aEntry,
+                               const void* aKey) {
+  const MsgHdrHashElement* hdr = static_cast<const MsgHdrHashElement*>(aEntry);
+  return aKey == (const void*)(uintptr_t)
+                     hdr->mKey;  // ### or get the key from the hdr...
+}
+
+void nsMsgDatabase::MoveEntry(PLDHashTable* aTable,
+                              const PLDHashEntryHdr* aFrom,
+                              PLDHashEntryHdr* aTo) {
+  new (KnownNotNull, aTo)
+      MsgHdrHashElement(std::move(*((MsgHdrHashElement*)aFrom)));
+}
+
+void nsMsgDatabase::ClearEntry(PLDHashTable* aTable, PLDHashEntryHdr* aEntry) {
+  MsgHdrHashElement* element = static_cast<MsgHdrHashElement*>(aEntry);
+  element->mHdr = nullptr;        // eh? Need to release this or not?
+  element->mKey = nsMsgKey_None;  // eh?
+}
+
+nsresult nsMsgDatabase::AddHdrToUseCache(nsIMsgDBHdr* hdr, nsMsgKey key) {
+  if (!m_headersInUse) {
+    mdb_count numHdrs = MSG_HASH_SIZE;
+    if (m_mdbAllMsgHeadersTable)
+      m_mdbAllMsgHeadersTable->GetCount(GetEnv(), &numHdrs);
+    m_headersInUse =
+        new PLDHashTable(&gMsgDBHashTableOps, sizeof(struct MsgHdrHashElement),
+                         std::max((mdb_count)MSG_HASH_SIZE, numHdrs));
+  }
+  if (m_headersInUse) {
+    if (key == nsMsgKey_None) hdr->GetMessageKey(&key);
+    PLDHashEntryHdr* entry =
+        m_headersInUse->Add((void*)(uintptr_t)key, mozilla::fallible);
+    if (!entry) return NS_ERROR_OUT_OF_MEMORY;  // XXX out of memory
+
+    MsgHdrHashElement* element = static_cast<MsgHdrHashElement*>(entry);
+    element->mHdr = hdr;
+    element->mKey = key;
+    // the hash table won't add ref, we'll do it ourselves
+    // stand for the addref that CreateMsgHdr normally does.
+    NS_ADDREF(hdr);
+    return NS_OK;
+  }
+
+  return NS_ERROR_OUT_OF_MEMORY;
+}
+
+nsresult nsMsgDatabase::ClearUseHdrCache() {
+  if (m_headersInUse) {
+    // clear mdb row pointers of any headers still in use, because the
+    // underlying db is going away.
+    for (auto iter = m_headersInUse->Iter(); !iter.Done(); iter.Next()) {
+      auto element = static_cast<const MsgHdrHashElement*>(iter.Get());
+      if (element && element->mHdr) {
+        nsMsgHdr* msgHdr = static_cast<nsMsgHdr*>(
+            element->mHdr);  // closed system, so this is ok
+        // clear out m_mdbRow member variable - the db is going away, which
+        // means that this member variable might very well point to a mork db
+        // that is gone.
+        NS_IF_RELEASE(msgHdr->m_mdbRow);
+        //    NS_IF_RELEASE(msgHdr->m_mdb);
+      }
+    }
+    delete m_headersInUse;
+    m_headersInUse = nullptr;
+  }
+  return NS_OK;
+}
+
+nsresult nsMsgDatabase::RemoveHdrFromUseCache(nsIMsgDBHdr* hdr, nsMsgKey key) {
+  if (m_headersInUse) {
+    if (key == nsMsgKey_None) hdr->GetMessageKey(&key);
+
+    m_headersInUse->Remove((void*)(uintptr_t)key);
+  }
+  return NS_OK;
+}
+
+nsresult nsMsgDatabase::CreateMsgHdr(nsIMdbRow* hdrRow, nsMsgKey key,
+                                     nsIMsgDBHdr** result) {
+  NS_ENSURE_ARG_POINTER(hdrRow);
+  NS_ENSURE_ARG_POINTER(result);
+
+  nsresult rv = GetHdrFromUseCache(key, result);
+  if (NS_SUCCEEDED(rv) && *result) {
+    hdrRow->Release();
+    return rv;
+  }
+
+  nsMsgHdr* msgHdr = new nsMsgHdr(this, hdrRow);
+  if (!msgHdr) return NS_ERROR_OUT_OF_MEMORY;
+  msgHdr->SetMessageKey(key);
+  // don't need to addref here; GetHdrFromUseCache addrefs.
+  *result = msgHdr;
+
+  AddHdrToCache(msgHdr, key);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::AddListener(nsIDBChangeListener* aListener) {
+  NS_ENSURE_ARG_POINTER(aListener);
+  m_ChangeListeners.AppendElementUnlessExists(aListener);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::RemoveListener(nsIDBChangeListener* aListener) {
+  NS_ENSURE_ARG_POINTER(aListener);
+  m_ChangeListeners.RemoveElement(aListener);
+  return NS_OK;
+}
+
+// XXX should we return rv for listener->propertyfunc_?
+#define NOTIFY_LISTENERS(propertyfunc_, params_)                         \
+  PR_BEGIN_MACRO                                                         \
+  nsTObserverArray<nsCOMPtr<nsIDBChangeListener>>::ForwardIterator iter( \
+      m_ChangeListeners);                                                \
+  nsCOMPtr<nsIDBChangeListener> listener;                                \
+  while (iter.HasMore()) {                                               \
+    listener = iter.GetNext();                                           \
+    listener->propertyfunc_ params_;                                     \
+  }                                                                      \
+  PR_END_MACRO
+
+// change announcer methods - just broadcast to all listeners.
+NS_IMETHODIMP nsMsgDatabase::NotifyHdrChangeAll(
+    nsIMsgDBHdr* aHdrChanged, uint32_t aOldFlags, uint32_t aNewFlags,
+    nsIDBChangeListener* aInstigator) {
+  // We will only notify the change if the header exists in the database.
+  // This allows database functions to be usable in both the case where the
+  // header is in the db, or the header is not so no notifications should be
+  // given.
+  nsMsgKey key;
+  bool inDb = false;
+  if (aHdrChanged) {
+    aHdrChanged->GetMessageKey(&key);
+    ContainsKey(key, &inDb);
+  }
+  if (inDb)
+    NOTIFY_LISTENERS(OnHdrFlagsChanged,
+                     (aHdrChanged, aOldFlags, aNewFlags, aInstigator));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::NotifyReadChanged(
+    nsIDBChangeListener* aInstigator) {
+  NOTIFY_LISTENERS(OnReadChanged, (aInstigator));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::NotifyJunkScoreChanged(
+    nsIDBChangeListener* aInstigator) {
+  NOTIFY_LISTENERS(OnJunkScoreChanged, (aInstigator));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::NotifyHdrDeletedAll(
+    nsIMsgDBHdr* aHdrDeleted, nsMsgKey aParentKey, int32_t aFlags,
+    nsIDBChangeListener* aInstigator) {
+  NOTIFY_LISTENERS(OnHdrDeleted,
+                   (aHdrDeleted, aParentKey, aFlags, aInstigator));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::NotifyHdrAddedAll(
+    nsIMsgDBHdr* aHdrAdded, nsMsgKey aParentKey, int32_t aFlags,
+    nsIDBChangeListener* aInstigator) {
+#ifdef DEBUG_bienvenu1
+  printf("notifying add of %ld parent %ld\n", keyAdded, parentKey);
+#endif
+  NOTIFY_LISTENERS(OnHdrAdded, (aHdrAdded, aParentKey, aFlags, aInstigator));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::NotifyParentChangedAll(
+    nsMsgKey aKeyReparented, nsMsgKey aOldParent, nsMsgKey aNewParent,
+    nsIDBChangeListener* aInstigator) {
+  NOTIFY_LISTENERS(OnParentChanged,
+                   (aKeyReparented, aOldParent, aNewParent, aInstigator));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::NotifyAnnouncerGoingAway(void) {
+  NOTIFY_LISTENERS(OnAnnouncerGoingAway, (this));
+  return NS_OK;
+}
+
+bool nsMsgDatabase::MatchDbName(nsIFile* dbFile)  // returns true if they match
+{
+  NS_ENSURE_TRUE(m_dbFile, false);
+  return dbFile->NativePath().Equals(m_dbFile->NativePath());
+}
+
+void nsMsgDBService::AddToCache(nsMsgDatabase* pMessageDB) {
+#ifdef DEBUG_David_Bienvenu
+  NS_ASSERTION(m_dbCache.Length() < 50, "50 or more open db's");
+#endif
+#ifdef DEBUG
+  if (pMessageDB->m_folder) {
+    nsCOMPtr<nsIMsgDatabase> msgDB;
+    CachedDBForFolder(pMessageDB->m_folder, getter_AddRefs(msgDB));
+    NS_ASSERTION(!msgDB, "shouldn't have db in cache");
+  }
+#endif
+  m_dbCache.AppendElement(pMessageDB);
+}
+
+/**
+ * Log the open db's, and how many headers are in memory.
+ */
+void nsMsgDBService::DumpCache() {
+  nsMsgDatabase* db = nullptr;
+  MOZ_LOG(DBLog, LogLevel::Info, ("%zu open DBs", m_dbCache.Length()));
+  for (uint32_t i = 0; i < m_dbCache.Length(); i++) {
+    db = m_dbCache.ElementAt(i);
+    MOZ_LOG(DBLog, LogLevel::Info,
+            ("%s - %" PRIu32 " hdrs in use",
+             db->m_dbFile->HumanReadablePath().get(),
+             db->m_headersInUse ? db->m_headersInUse->EntryCount() : 0));
+  }
+}
+
+// Memory Reporting implementations
+
+size_t nsMsgDatabase::SizeOfExcludingThis(
+    mozilla::MallocSizeOf aMallocSizeOf) const {
+  size_t totalSize = 0;
+  if (m_dbFolderInfo)
+    totalSize += m_dbFolderInfo->SizeOfExcludingThis(aMallocSizeOf);
+  if (m_mdbEnv) {
+    nsIMdbHeap* morkHeap = nullptr;
+    m_mdbEnv->GetHeap(&morkHeap);
+    if (morkHeap) totalSize += morkHeap->GetUsedSize();
+  }
+  totalSize += m_newSet.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  totalSize += m_ChangeListeners.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  totalSize += m_threads.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  // We have two tables of header objects, but every header in m_cachedHeaders
+  // should be in m_headersInUse.
+  // double-counting...
+  size_t headerSize = 0;
+  if (m_headersInUse) {
+    headerSize = m_headersInUse->ShallowSizeOfIncludingThis(aMallocSizeOf);
+    for (auto iter = m_headersInUse->Iter(); !iter.Done(); iter.Next()) {
+      auto entry = static_cast<MsgHdrHashElement*>(iter.Get());
+      // Sigh, this is dangerous, but so long as this is a closed system, this
+      // is safe.
+      headerSize += static_cast<nsMsgHdr*>(entry->mHdr)
+                        ->SizeOfIncludingThis(aMallocSizeOf);
+    }
+  }
+  totalSize += headerSize;
+  if (m_msgReferences)
+    totalSize += m_msgReferences->ShallowSizeOfIncludingThis(aMallocSizeOf);
+  return totalSize;
+}
+
+namespace mozilla {
+namespace mailnews {
+
+MOZ_DEFINE_MALLOC_SIZE_OF(GetMallocSize)
+
+class MsgDBReporter final : public nsIMemoryReporter {
+  nsWeakPtr mDatabase;
+
+ public:
+  explicit MsgDBReporter(nsMsgDatabase* db)
+      : mDatabase(do_GetWeakReference(db)) {}
+
+  NS_DECL_ISUPPORTS
+  NS_IMETHOD GetName(nsACString& aName) {
+    aName.AssignLiteral("msg-database-objects");
+    return NS_OK;
+  }
+
+  NS_IMETHOD CollectReports(nsIHandleReportCallback* aCb, nsISupports* aClosure,
+                            bool aAnonymize) override {
+    nsCString path;
+    GetPath(path, aAnonymize);
+    nsCOMPtr<nsIMsgDatabase> database = do_QueryReferent(mDatabase);
+    nsMsgDatabase* db =
+        database ? static_cast<nsMsgDatabase*>(database.get()) : nullptr;
+    return aCb->Callback(EmptyCString(), path, nsIMemoryReporter::KIND_HEAP,
+                         nsIMemoryReporter::UNITS_BYTES,
+                         db ? db->SizeOfIncludingThis(GetMallocSize) : 0,
+                         "Memory used for the folder database."_ns, aClosure);
+  }
+
+  void GetPath(nsACString& memoryPath, bool aAnonymize) {
+    memoryPath.AssignLiteral("explicit/maildb/database(");
+    nsCOMPtr<nsIMsgDatabase> database = do_QueryReferent(mDatabase);
+    nsCOMPtr<nsIMsgFolder> folder;
+    if (database) database->GetFolder(getter_AddRefs(folder));
+    if (folder) {
+      if (aAnonymize)
+        memoryPath.AppendLiteral("<anonymized>");
+      else {
+        nsAutoCString folderURL;
+        folder->GetFolderURL(folderURL);
+        folderURL.ReplaceChar('/', '\\');
+        memoryPath += folderURL;
+      }
+    } else {
+      memoryPath.AppendLiteral("UNKNOWN-FOLDER");
+    }
+    memoryPath.Append(')');
+  }
+
+ private:
+  ~MsgDBReporter() {}
+};
+
+NS_IMPL_ISUPPORTS(MsgDBReporter, nsIMemoryReporter)
+}  // namespace mailnews
+}  // namespace mozilla
+
+nsMsgDatabase::nsMsgDatabase()
+    : m_dbFolderInfo(nullptr),
+      m_nextPseudoMsgKey(kFirstPseudoKey),
+      m_mdbEnv(nullptr),
+      m_mdbStore(nullptr),
+      m_mdbAllMsgHeadersTable(nullptr),
+      m_mdbAllThreadsTable(nullptr),
+      m_create(false),
+      m_leaveInvalidDB(false),
+      m_mdbTokensInitialized(false),
+      m_hdrRowScopeToken(0),
+      m_hdrTableKindToken(0),
+      m_threadTableKindToken(0),
+      m_subjectColumnToken(0),
+      m_senderColumnToken(0),
+      m_messageIdColumnToken(0),
+      m_referencesColumnToken(0),
+      m_recipientsColumnToken(0),
+      m_dateColumnToken(0),
+      m_messageSizeColumnToken(0),
+      m_flagsColumnToken(0),
+      m_priorityColumnToken(0),
+      m_labelColumnToken(0),
+      m_numLinesColumnToken(0),
+      m_ccListColumnToken(0),
+      m_bccListColumnToken(0),
+      m_threadFlagsColumnToken(0),
+      m_threadIdColumnToken(0),
+      m_threadChildrenColumnToken(0),
+      m_threadUnreadChildrenColumnToken(0),
+      m_messageThreadIdColumnToken(0),
+      m_threadSubjectColumnToken(0),
+      m_messageCharSetColumnToken(0),
+      m_threadParentColumnToken(0),
+      m_threadRootKeyColumnToken(0),
+      m_threadNewestMsgDateColumnToken(0),
+      m_offlineMsgOffsetColumnToken(0),
+      m_offlineMessageSizeColumnToken(0),
+      m_headersInUse(nullptr),
+      m_cachedHeaders(nullptr),
+      m_bCacheHeaders(true),
+      m_cachedThreadId(nsMsgKey_None),
+      m_msgReferences(nullptr),
+      m_cacheSize(kMaxHdrsInCache) {
+  mMemReporter = new mozilla::mailnews::MsgDBReporter(this);
+  mozilla::RegisterWeakMemoryReporter(mMemReporter);
+}
+
+nsMsgDatabase::~nsMsgDatabase() {
+  mozilla::UnregisterWeakMemoryReporter(mMemReporter);
+  mMemReporter = nullptr;
+  //  Close(FALSE);  // better have already been closed.
+  ClearCachedObjects(true);
+  InvalidateEnumerators();
+  delete m_cachedHeaders;
+  delete m_headersInUse;
+
+  if (m_msgReferences) {
+    delete m_msgReferences;
+    m_msgReferences = nullptr;
+  }
+
+  MOZ_LOG(DBLog, LogLevel::Info,
+          ("closing database    %s", m_dbFile->HumanReadablePath().get()));
+
+  nsCOMPtr<nsIMsgDBService> serv(
+      do_GetService("@mozilla.org/msgDatabase/msgDBService;1"));
+  if (serv) static_cast<nsMsgDBService*>(serv.get())->RemoveFromCache(this);
+
+  // if the db folder info refers to the mdb db, we must clear it because
+  // the reference will be a dangling one soon.
+  if (m_dbFolderInfo) m_dbFolderInfo->ReleaseExternalReferences();
+  m_dbFolderInfo = nullptr;
+
+  if (m_mdbAllMsgHeadersTable) m_mdbAllMsgHeadersTable->Release();
+
+  if (m_mdbAllThreadsTable) m_mdbAllThreadsTable->Release();
+
+  if (m_mdbStore) m_mdbStore->Release();
+
+  if (m_mdbEnv) {
+    m_mdbEnv->Release();  //??? is this right?
+    m_mdbEnv = nullptr;
+  }
+  m_ChangeListeners.Clear();
+}
+
+NS_IMPL_ISUPPORTS(nsMsgDatabase, nsIMsgDatabase, nsIMsgOfflineOpsDatabase,
+                  nsIDBChangeAnnouncer)
+
+nsresult nsMsgDatabase::GetMDBFactory(nsIMdbFactory** aMdbFactory) {
+  if (!mMdbFactory) {
+    nsresult rv;
+    nsCOMPtr<nsIMdbFactoryService> mdbFactoryService =
+        do_GetService("@mozilla.org/db/mork;1", &rv);
+    if (NS_SUCCEEDED(rv) && mdbFactoryService) {
+      rv = mdbFactoryService->GetMdbFactory(getter_AddRefs(mMdbFactory));
+      NS_ENSURE_SUCCESS(rv, rv);
+      if (!mMdbFactory) return NS_ERROR_FAILURE;
+    }
+  }
+  NS_ADDREF(*aMdbFactory = mMdbFactory);
+  return NS_OK;
+}
+
+// aLeaveInvalidDB: true if caller wants back a db even out of date.
+// If so, they'll extract out the interesting info from the db, close it,
+// delete it, and then try to open the db again, prior to reparsing.
+nsresult nsMsgDatabase::Open(nsMsgDBService* aDBService, nsIFile* aFolderName,
+                             bool aCreate, bool aLeaveInvalidDB) {
+  return nsMsgDatabase::OpenInternal(aDBService, aFolderName, aCreate,
+                                     aLeaveInvalidDB,
+                                     true /* open synchronously */);
+}
+
+nsresult nsMsgDatabase::OpenInternal(nsMsgDBService* aDBService,
+                                     nsIFile* summaryFile, bool aCreate,
+                                     bool aLeaveInvalidDB, bool sync) {
+  MOZ_LOG(DBLog, LogLevel::Info,
+          ("nsMsgDatabase::Open(%s, %s, %p, %s)",
+           summaryFile->HumanReadablePath().get(), aCreate ? "TRUE" : "FALSE",
+           this, aLeaveInvalidDB ? "TRUE" : "FALSE"));
+
+  nsresult rv = OpenMDB(summaryFile, aCreate, sync);
+  if (NS_FAILED(rv))
+    MOZ_LOG(DBLog, LogLevel::Info,
+            ("error opening db %" PRIx32, static_cast<uint32_t>(rv)));
+
+  if (MOZ_LOG_TEST(DBLog, LogLevel::Debug)) aDBService->DumpCache();
+
+  if (rv == NS_ERROR_FILE_NOT_FOUND) return rv;
+
+  m_create = aCreate;
+  m_leaveInvalidDB = aLeaveInvalidDB;
+  if (!sync && NS_SUCCEEDED(rv)) {
+    aDBService->AddToCache(this);
+    // remember open options for when the parsing is complete.
+    return rv;
+  }
+  return CheckForErrors(rv, true, aDBService, summaryFile);
+}
+
+nsresult nsMsgDatabase::CheckForErrors(nsresult err, bool sync,
+                                       nsMsgDBService* aDBService,
+                                       nsIFile* summaryFile) {
+  nsCOMPtr<nsIDBFolderInfo> folderInfo;
+  bool summaryFileExists;
+  bool newFile = false;
+  bool deleteInvalidDB = false;
+
+  bool exists;
+  int64_t fileSize = 0;
+  summaryFile->Exists(&exists);
+  if (exists) summaryFile->GetFileSize(&fileSize);
+  // if the old summary doesn't exist, we're creating a new one.
+  if ((!exists || !fileSize) && m_create) newFile = true;
+
+  summaryFileExists = exists && fileSize > 0;
+
+  if (NS_SUCCEEDED(err)) {
+    if (!m_dbFolderInfo) {
+      err = NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE;
+    } else {
+      if (!newFile && summaryFileExists) {
+        bool valid = false;
+        nsresult rv = GetSummaryValid(&valid);
+        if (NS_FAILED(rv) || !valid)
+          err = NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE;
+      }
+      // compare current version of db versus filed out version info.
+      uint32_t version;
+      m_dbFolderInfo->GetVersion(&version);
+      if (GetCurVersion() != version)
+        err = NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE;
+
+      // Check if we should force a reparse because, for example, we have
+      // reached the key limit.
+      bool forceReparse;
+      m_dbFolderInfo->GetBooleanProperty("forceReparse", false, &forceReparse);
+      if (forceReparse) {
+        NS_WARNING("Forcing a reparse presumably because key limit reached");
+        err = NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE;
+      }
+    }
+    if (NS_FAILED(err) && !m_leaveInvalidDB) deleteInvalidDB = true;
+  } else if (err != NS_MSG_ERROR_FOLDER_SUMMARY_MISSING) {
+    // No point declaring it out-of-date and trying to delete it
+    // if it's missing.
+    // We get here with NS_ERROR_FAILURE when Mork can't open the
+    // file due to too many open files. In this case there is no
+    // point to blow away the MSF file.
+    err = NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE;
+    if (!m_leaveInvalidDB) deleteInvalidDB = true;
+  }
+
+  if (deleteInvalidDB) {
+    // this will make the db folder info release its ref to the mail db...
+    m_dbFolderInfo = nullptr;
+    ForceClosed();
+    if (err == NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE)
+      summaryFile->Remove(false);
+  }
+  if (NS_FAILED(err) || newFile) {
+    // if we couldn't open file, or we have a blank one, and we're supposed
+    // to upgrade, upgrade it.
+    if (newFile && !m_leaveInvalidDB)  // caller is upgrading, and we have empty
+                                       // summary file,
+    {  // leave db around and open so caller can upgrade it.
+      err = NS_MSG_ERROR_FOLDER_SUMMARY_MISSING;
+    } else if (NS_FAILED(err) &&
+               err != NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE) {
+      Close(false);
+      summaryFile->Remove(false);  // blow away the db if it's corrupt.
+    }
+  }
+  if (sync && (NS_SUCCEEDED(err) || err == NS_MSG_ERROR_FOLDER_SUMMARY_MISSING))
+    aDBService->AddToCache(this);
+  return (summaryFileExists) ? err : NS_MSG_ERROR_FOLDER_SUMMARY_MISSING;
+}
+
+/**
+ * Open the MDB database synchronously or async based on sync argument.
+ * If successful, this routine will set up the m_mdbStore and m_mdbEnv of
+ * the database object so other database calls can work.
+ */
+nsresult nsMsgDatabase::OpenMDB(nsIFile* dbFile, bool create, bool sync) {
+  nsCOMPtr<nsIMdbFactory> mdbFactory;
+  nsresult ret = GetMDBFactory(getter_AddRefs(mdbFactory));
+  NS_ENSURE_SUCCESS(ret, ret);
+
+  ret = mdbFactory->MakeEnv(NULL, &m_mdbEnv);
+  if (NS_SUCCEEDED(ret)) {
+    nsIMdbHeap* dbHeap = nullptr;
+
+    if (m_mdbEnv) m_mdbEnv->SetAutoClear(true);
+    PathString dbName = dbFile->NativePath();
+    ret = dbFile->Clone(getter_AddRefs(m_dbFile));
+    NS_ENSURE_SUCCESS(ret, ret);
+    bool exists = false;
+    ret = dbFile->Exists(&exists);
+    if (!exists) {
+      ret = NS_MSG_ERROR_FOLDER_SUMMARY_MISSING;
+    }
+    // If m_thumb is set, we're asynchronously opening the db already.
+    else if (!m_thumb) {
+      mdbOpenPolicy inOpenPolicy;
+      mdb_bool canOpen;
+      mdbYarn outFormatVersion;
+
+      nsIMdbFile* oldFile = nullptr;
+      ret = mdbFactory->OpenOldFile(
+          m_mdbEnv, dbHeap, dbName.get(),
+          mdbBool_kFalse,  // not readonly, we want modifiable
+          &oldFile);
+      if (oldFile) {
+        if (NS_SUCCEEDED(ret)) {
+          ret = mdbFactory->CanOpenFilePort(m_mdbEnv,
+                                            oldFile,  // the file to investigate
+                                            &canOpen, &outFormatVersion);
+          if (NS_SUCCEEDED(ret) && canOpen) {
+            inOpenPolicy.mOpenPolicy_ScopePlan.mScopeStringSet_Count = 0;
+            inOpenPolicy.mOpenPolicy_MinMemory = 0;
+            inOpenPolicy.mOpenPolicy_MaxLazy = 0;
+
+            ret = mdbFactory->OpenFileStore(m_mdbEnv, dbHeap, oldFile,
+                                            &inOpenPolicy,
+                                            getter_AddRefs(m_thumb));
+          } else
+            ret = NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE;
+        }
+        NS_RELEASE(oldFile);  // always release our file ref, store has own
+      }
+    }
+    if (NS_SUCCEEDED(ret) && m_thumb && sync) {
+      mdb_count outTotal;        // total somethings to do in operation
+      mdb_count outCurrent;      // subportion of total completed so far
+      mdb_bool outDone = false;  // is operation finished?
+      mdb_bool outBroken;        // is operation irreparably dead and broken?
+      do {
+        ret = m_thumb->DoMore(m_mdbEnv, &outTotal, &outCurrent, &outDone,
+                              &outBroken);
+        if (NS_FAILED(ret)) {  // mork isn't really doing NS errors yet.
+          outDone = true;
+          break;
+        }
+      } while (NS_SUCCEEDED(ret) && !outBroken && !outDone);
+      //        m_mdbEnv->ClearErrors(); // ### temporary...
+      // only 0 is a non-error return.
+      if (NS_SUCCEEDED(ret) && outDone) {
+        ret = mdbFactory->ThumbToOpenStore(m_mdbEnv, m_thumb, &m_mdbStore);
+        if (NS_SUCCEEDED(ret))
+          ret = (m_mdbStore) ? InitExistingDB() : NS_ERROR_FAILURE;
+      }
+#ifdef DEBUG_bienvenu1
+      DumpContents();
+#endif
+      m_thumb = nullptr;
+    } else if (create)  // ### need error code saying why open file store failed
+    {
+      nsIMdbFile* newFile = 0;
+      ret = mdbFactory->CreateNewFile(m_mdbEnv, dbHeap, dbName.get(), &newFile);
+      if (NS_FAILED(ret)) ret = NS_ERROR_FILE_NOT_FOUND;
+      if (newFile) {
+        if (NS_SUCCEEDED(ret)) {
+          mdbOpenPolicy inOpenPolicy;
+
+          inOpenPolicy.mOpenPolicy_ScopePlan.mScopeStringSet_Count = 0;
+          inOpenPolicy.mOpenPolicy_MinMemory = 0;
+          inOpenPolicy.mOpenPolicy_MaxLazy = 0;
+
+          ret = mdbFactory->CreateNewFileStore(m_mdbEnv, dbHeap, newFile,
+                                               &inOpenPolicy, &m_mdbStore);
+          if (NS_SUCCEEDED(ret))
+            ret = (m_mdbStore) ? InitNewDB() : NS_ERROR_FAILURE;
+        }
+        NS_RELEASE(newFile);  // always release our file ref, store has own
+      }
+    }
+  }
+
+  return ret;
+}
+
+nsresult nsMsgDatabase::CloseMDB(bool commit) {
+  if (commit) Commit(nsMsgDBCommitType::kSessionCommit);
+  return (NS_OK);
+}
+
+// force the database to close - this'll flush out anybody holding onto
+// a database without having a listener!
+// This is evil in the com world, but there are times we need to delete the
+// file.
+NS_IMETHODIMP nsMsgDatabase::ForceClosed() {
+  nsresult err = NS_OK;
+
+  // make sure someone has a reference so object won't get deleted out from
+  // under us.
+  NS_ADDREF_THIS();
+  NotifyAnnouncerGoingAway();
+  // make sure dbFolderInfo isn't holding onto mork stuff because mork db is
+  // going away
+  if (m_dbFolderInfo) m_dbFolderInfo->ReleaseExternalReferences();
+  m_dbFolderInfo = nullptr;
+
+  err = CloseMDB(true);  // Backup DB will try to recover info, so commit
+  ClearCachedObjects(true);
+  InvalidateEnumerators();
+  if (m_mdbAllMsgHeadersTable) {
+    m_mdbAllMsgHeadersTable->Release();
+    m_mdbAllMsgHeadersTable = nullptr;
+  }
+  if (m_mdbAllThreadsTable) {
+    m_mdbAllThreadsTable->Release();
+    m_mdbAllThreadsTable = nullptr;
+  }
+  if (m_mdbStore) {
+    m_mdbStore->Release();
+    m_mdbStore = nullptr;
+  }
+
+  // There'd better not be any listeners, because we're going away.
+  NS_ASSERTION(m_ChangeListeners.IsEmpty(),
+               "shouldn't have any listeners left");
+  m_ChangeListeners.Clear();
+
+  NS_RELEASE_THIS();
+  return err;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetDBFolderInfo(nsIDBFolderInfo** result) {
+  if (!m_dbFolderInfo) {
+    NS_ERROR("db must be corrupt");
+    return NS_ERROR_NULL_POINTER;
+  }
+  NS_ADDREF(*result = m_dbFolderInfo);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetFolder(nsIMsgFolder** aFolder) {
+  NS_ENSURE_ARG_POINTER(aFolder);
+  NS_IF_ADDREF(*aFolder = m_folder);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::Commit(nsMsgDBCommit commitType) {
+  nsresult err = NS_OK;
+  nsCOMPtr<nsIMdbThumb> commitThumb;
+
+  RememberLastUseTime();
+  if (commitType == nsMsgDBCommitType::kLargeCommit ||
+      commitType == nsMsgDBCommitType::kSessionCommit) {
+    mdb_percent outActualWaste = 0;
+    mdb_bool outShould;
+    if (m_mdbStore) {
+      err =
+          m_mdbStore->ShouldCompress(GetEnv(), 30, &outActualWaste, &outShould);
+      if (NS_SUCCEEDED(err) && outShould)
+        commitType = nsMsgDBCommitType::kCompressCommit;
+    }
+  }
+  //  commitType = nsMsgDBCommitType::kCompressCommit;  // ### until incremental
+  //  writing works.
+
+  if (m_mdbStore) {
+    switch (commitType) {
+      case nsMsgDBCommitType::kLargeCommit:
+        err = m_mdbStore->LargeCommit(GetEnv(), getter_AddRefs(commitThumb));
+        break;
+      case nsMsgDBCommitType::kSessionCommit:
+        err = m_mdbStore->SessionCommit(GetEnv(), getter_AddRefs(commitThumb));
+        break;
+      case nsMsgDBCommitType::kCompressCommit:
+        err = m_mdbStore->CompressCommit(GetEnv(), getter_AddRefs(commitThumb));
+        break;
+    }
+  }
+  if (commitThumb) {
+    mdb_count outTotal = 0;      // total somethings to do in operation
+    mdb_count outCurrent = 0;    // subportion of total completed so far
+    mdb_bool outDone = false;    // is operation finished?
+    mdb_bool outBroken = false;  // is operation irreparably dead and broken?
+    while (!outDone && !outBroken && NS_SUCCEEDED(err)) {
+      err = commitThumb->DoMore(GetEnv(), &outTotal, &outCurrent, &outDone,
+                                &outBroken);
+    }
+  }
+  // ### do something with error, but clear it now because mork errors out on
+  // commits.
+  if (GetEnv()) GetEnv()->ClearErrors();
+
+  nsresult rv;
+  nsCOMPtr<nsIMsgAccountManager> accountManager =
+      do_GetService("@mozilla.org/messenger/account-manager;1", &rv);
+  if (NS_SUCCEEDED(rv) && accountManager) {
+    nsCOMPtr<nsIMsgFolderCache> folderCache;
+
+    rv = accountManager->GetFolderCache(getter_AddRefs(folderCache));
+    if (NS_SUCCEEDED(rv) && folderCache) {
+      nsCOMPtr<nsIMsgFolderCacheElement> cacheElement;
+      nsCString persistentPath;
+      NS_ENSURE_TRUE(m_dbFile, NS_ERROR_NULL_POINTER);
+      rv = m_dbFile->GetPersistentDescriptor(persistentPath);
+      NS_ENSURE_SUCCESS(rv, err);
+      rv = folderCache->GetCacheElement(persistentPath, false,
+                                        getter_AddRefs(cacheElement));
+      if (NS_SUCCEEDED(rv) && cacheElement && m_dbFolderInfo) {
+        int32_t totalMessages, unreadMessages, pendingMessages,
+            pendingUnreadMessages;
+
+        m_dbFolderInfo->GetNumMessages(&totalMessages);
+        m_dbFolderInfo->GetNumUnreadMessages(&unreadMessages);
+        m_dbFolderInfo->GetImapUnreadPendingMessages(&pendingUnreadMessages);
+        m_dbFolderInfo->GetImapTotalPendingMessages(&pendingMessages);
+        cacheElement->SetCachedInt32("totalMsgs", totalMessages);
+        cacheElement->SetCachedInt32("totalUnreadMsgs", unreadMessages);
+        cacheElement->SetCachedInt32("pendingMsgs", pendingMessages);
+        cacheElement->SetCachedInt32("pendingUnreadMsgs",
+                                     pendingUnreadMessages);
+      }
+    }
+  }
+
+  return err;
+}
+
+NS_IMETHODIMP nsMsgDatabase::Close(bool forceCommit /* = TRUE */) {
+  InvalidateEnumerators();
+  return CloseMDB(forceCommit);
+}
+
+const char* kMsgHdrsScope =
+    "ns:msg:db:row:scope:msgs:all";  // scope for all headers table
+const char* kMsgHdrsTableKind = "ns:msg:db:table:kind:msgs";
+const char* kThreadTableKind = "ns:msg:db:table:kind:thread";
+const char* kThreadHdrsScope =
+    "ns:msg:db:row:scope:threads:all";  // scope for all threads table
+const char* kAllThreadsTableKind =
+    "ns:msg:db:table:kind:allthreads";  // kind for table of all threads
+const char* kSubjectColumnName = "subject";
+const char* kSenderColumnName = "sender";
+const char* kMessageIdColumnName = "message-id";
+const char* kReferencesColumnName = "references";
+const char* kRecipientsColumnName = "recipients";
+const char* kDateColumnName = "date";
+const char* kMessageSizeColumnName = "size";
+const char* kFlagsColumnName = "flags";
+const char* kPriorityColumnName = "priority";
+const char* kLabelColumnName = "label";
+const char* kNumLinesColumnName = "numLines";
+const char* kCCListColumnName = "ccList";
+const char* kBCCListColumnName = "bccList";
+const char* kMessageThreadIdColumnName = "msgThreadId";
+const char* kThreadFlagsColumnName = "threadFlags";
+const char* kThreadIdColumnName = "threadId";
+const char* kThreadChildrenColumnName = "children";
+const char* kThreadUnreadChildrenColumnName = "unreadChildren";
+const char* kThreadSubjectColumnName = "threadSubject";
+const char* kMessageCharSetColumnName = "msgCharSet";
+const char* kThreadParentColumnName = "threadParent";
+const char* kThreadRootColumnName = "threadRoot";
+const char* kThreadNewestMsgDateColumnName = "threadNewestMsgDate";
+const char* kOfflineMsgOffsetColumnName = "msgOffset";
+const char* kOfflineMsgSizeColumnName = "offlineMsgSize";
+struct mdbOid gAllMsgHdrsTableOID;
+struct mdbOid gAllThreadsTableOID;
+const char* kFixedBadRefThreadingProp = "fixedBadRefThreading";
+
+// set up empty tables, dbFolderInfo, etc.
+nsresult nsMsgDatabase::InitNewDB() {
+  nsresult err = NS_OK;
+
+  err = InitMDBInfo();
+  if (NS_SUCCEEDED(err)) {
+    nsDBFolderInfo* dbFolderInfo = new nsDBFolderInfo(this);
+    if (dbFolderInfo) {
+      err = dbFolderInfo->AddToNewMDB();
+      dbFolderInfo->SetVersion(GetCurVersion());
+      dbFolderInfo->SetBooleanProperty("forceReparse", false);
+      dbFolderInfo->SetBooleanProperty(kFixedBadRefThreadingProp, true);
+      nsIMdbStore* store = GetStore();
+      // create the unique table for the dbFolderInfo.
+      struct mdbOid allMsgHdrsTableOID;
+      struct mdbOid allThreadsTableOID;
+      if (!store) return NS_ERROR_NULL_POINTER;
+
+      allMsgHdrsTableOID.mOid_Scope = m_hdrRowScopeToken;
+      allMsgHdrsTableOID.mOid_Id = kAllMsgHdrsTableKey;
+      allThreadsTableOID.mOid_Scope = m_threadRowScopeToken;
+      allThreadsTableOID.mOid_Id = kAllThreadsTableKey;
+
+      // TODO: check this error value?
+      (void)store->NewTableWithOid(GetEnv(), &allMsgHdrsTableOID,
+                                   m_hdrTableKindToken, false, nullptr,
+                                   &m_mdbAllMsgHeadersTable);
+
+      // error here is not fatal.
+      (void)store->NewTableWithOid(GetEnv(), &allThreadsTableOID,
+                                   m_allThreadsTableKindToken, false, nullptr,
+                                   &m_mdbAllThreadsTable);
+
+      m_dbFolderInfo = dbFolderInfo;
+
+    } else
+      err = NS_ERROR_OUT_OF_MEMORY;
+  }
+  return err;
+}
+
+nsresult nsMsgDatabase::GetTableCreateIfMissing(const char* scope,
+                                                const char* kind,
+                                                nsIMdbTable** table,
+                                                mdb_token& scopeToken,
+                                                mdb_token& kindToken) {
+  struct mdbOid tableOID;
+
+  if (!m_mdbStore) return NS_ERROR_FAILURE;
+  (void)m_mdbStore->StringToToken(GetEnv(), scope, &scopeToken);
+  (void)m_mdbStore->StringToToken(GetEnv(), kind, &kindToken);
+  tableOID.mOid_Scope = scopeToken;
+  tableOID.mOid_Id = 1;
+
+  nsresult rv = m_mdbStore->GetTable(GetEnv(), &tableOID, table);
+  NS_ENSURE_SUCCESS(rv, NS_ERROR_FAILURE);
+
+  // create new all all offline ops table, if it doesn't exist.
+  if (NS_SUCCEEDED(rv) && !*table) {
+    rv = m_mdbStore->NewTable(GetEnv(), scopeToken, kindToken, false, nullptr,
+                              table);
+    if (NS_FAILED(rv) || !*table) rv = NS_ERROR_FAILURE;
+  }
+  NS_ASSERTION(NS_SUCCEEDED(rv), "couldn't create offline ops table");
+  return rv;
+}
+
+nsresult nsMsgDatabase::InitExistingDB() {
+  nsresult err = NS_OK;
+
+  err = InitMDBInfo();
+  if (NS_SUCCEEDED(err)) {
+    err = GetStore()->GetTable(GetEnv(), &gAllMsgHdrsTableOID,
+                               &m_mdbAllMsgHeadersTable);
+    if (NS_SUCCEEDED(err)) {
+      m_dbFolderInfo = new nsDBFolderInfo(this);
+      if (m_dbFolderInfo) {
+        err = m_dbFolderInfo->InitFromExistingDB();
+      }
+    } else
+      err = NS_ERROR_FAILURE;
+
+    NS_ASSERTION(NS_SUCCEEDED(err), "failed initing existing db");
+    NS_ENSURE_SUCCESS(err, err);
+    // create new all msg hdrs table, if it doesn't exist.
+    if (NS_SUCCEEDED(err) && !m_mdbAllMsgHeadersTable) {
+      struct mdbOid allMsgHdrsTableOID;
+      allMsgHdrsTableOID.mOid_Scope = m_hdrRowScopeToken;
+      allMsgHdrsTableOID.mOid_Id = kAllMsgHdrsTableKey;
+
+      nsresult mdberr = GetStore()->NewTableWithOid(
+          GetEnv(), &allMsgHdrsTableOID, m_hdrTableKindToken, false, nullptr,
+          &m_mdbAllMsgHeadersTable);
+      if (NS_FAILED(mdberr) || !m_mdbAllMsgHeadersTable) err = NS_ERROR_FAILURE;
+    }
+    struct mdbOid allThreadsTableOID;
+    allThreadsTableOID.mOid_Scope = m_threadRowScopeToken;
+    allThreadsTableOID.mOid_Id = kAllThreadsTableKey;
+    err = GetStore()->GetTable(GetEnv(), &gAllThreadsTableOID,
+                               &m_mdbAllThreadsTable);
+    if (!m_mdbAllThreadsTable) {
+      nsresult mdberr = GetStore()->NewTableWithOid(
+          GetEnv(), &allThreadsTableOID, m_allThreadsTableKindToken, false,
+          nullptr, &m_mdbAllThreadsTable);
+      if (NS_FAILED(mdberr) || !m_mdbAllThreadsTable) err = NS_ERROR_FAILURE;
+    }
+  }
+  if (NS_SUCCEEDED(err) && m_dbFolderInfo) {
+    bool fixedBadRefThreading;
+    m_dbFolderInfo->GetBooleanProperty(kFixedBadRefThreadingProp, false,
+                                       &fixedBadRefThreading);
+    if (!fixedBadRefThreading) {
+      nsCOMPtr<nsIMsgEnumerator> enumerator;
+      err = EnumerateMessages(getter_AddRefs(enumerator));
+      if (NS_SUCCEEDED(err) && enumerator) {
+        bool hasMore;
+
+        while (NS_SUCCEEDED(err = enumerator->HasMoreElements(&hasMore)) &&
+               hasMore) {
+          nsCOMPtr<nsIMsgDBHdr> msgHdr;
+          err = enumerator->GetNext(getter_AddRefs(msgHdr));
+          if (msgHdr && NS_SUCCEEDED(err)) {
+            nsCString messageId;
+            nsAutoCString firstReference;
+            msgHdr->GetMessageId(getter_Copies(messageId));
+            msgHdr->GetStringReference(0, firstReference);
+            if (messageId.Equals(firstReference)) {
+              err = NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE;
+              break;
+            }
+          }
+        }
+      }
+
+      m_dbFolderInfo->SetBooleanProperty(kFixedBadRefThreadingProp, true);
+    }
+  }
+  return err;
+}
+
+// initialize the various tokens and tables in our db's env
+nsresult nsMsgDatabase::InitMDBInfo() {
+  nsresult err = NS_OK;
+
+  if (!m_mdbTokensInitialized && GetStore()) {
+    m_mdbTokensInitialized = true;
+    err =
+        GetStore()->StringToToken(GetEnv(), kMsgHdrsScope, &m_hdrRowScopeToken);
+    if (NS_SUCCEEDED(err)) {
+      GetStore()->StringToToken(GetEnv(), kSubjectColumnName,
+                                &m_subjectColumnToken);
+      GetStore()->StringToToken(GetEnv(), kSenderColumnName,
+                                &m_senderColumnToken);
+      GetStore()->StringToToken(GetEnv(), kMessageIdColumnName,
+                                &m_messageIdColumnToken);
+      // if we just store references as a string, we won't get any savings from
+      // the fact there's a lot of duplication. So we may want to break them up
+      // into multiple columns, r1, r2, etc.
+      GetStore()->StringToToken(GetEnv(), kReferencesColumnName,
+                                &m_referencesColumnToken);
+      // similarly, recipients could be tokenized properties
+      GetStore()->StringToToken(GetEnv(), kRecipientsColumnName,
+                                &m_recipientsColumnToken);
+      GetStore()->StringToToken(GetEnv(), kDateColumnName, &m_dateColumnToken);
+      GetStore()->StringToToken(GetEnv(), kMessageSizeColumnName,
+                                &m_messageSizeColumnToken);
+      GetStore()->StringToToken(GetEnv(), kFlagsColumnName,
+                                &m_flagsColumnToken);
+      GetStore()->StringToToken(GetEnv(), kPriorityColumnName,
+                                &m_priorityColumnToken);
+      GetStore()->StringToToken(GetEnv(), kLabelColumnName,
+                                &m_labelColumnToken);
+      GetStore()->StringToToken(GetEnv(), kNumLinesColumnName,
+                                &m_numLinesColumnToken);
+      GetStore()->StringToToken(GetEnv(), kCCListColumnName,
+                                &m_ccListColumnToken);
+      GetStore()->StringToToken(GetEnv(), kBCCListColumnName,
+                                &m_bccListColumnToken);
+      GetStore()->StringToToken(GetEnv(), kMessageThreadIdColumnName,
+                                &m_messageThreadIdColumnToken);
+      GetStore()->StringToToken(GetEnv(), kThreadIdColumnName,
+                                &m_threadIdColumnToken);
+      GetStore()->StringToToken(GetEnv(), kThreadFlagsColumnName,
+                                &m_threadFlagsColumnToken);
+      GetStore()->StringToToken(GetEnv(), kThreadNewestMsgDateColumnName,
+                                &m_threadNewestMsgDateColumnToken);
+      GetStore()->StringToToken(GetEnv(), kThreadChildrenColumnName,
+                                &m_threadChildrenColumnToken);
+      GetStore()->StringToToken(GetEnv(), kThreadUnreadChildrenColumnName,
+                                &m_threadUnreadChildrenColumnToken);
+      GetStore()->StringToToken(GetEnv(), kThreadSubjectColumnName,
+                                &m_threadSubjectColumnToken);
+      GetStore()->StringToToken(GetEnv(), kMessageCharSetColumnName,
+                                &m_messageCharSetColumnToken);
+      err = GetStore()->StringToToken(GetEnv(), kMsgHdrsTableKind,
+                                      &m_hdrTableKindToken);
+      if (NS_SUCCEEDED(err))
+        err = GetStore()->StringToToken(GetEnv(), kThreadTableKind,
+                                        &m_threadTableKindToken);
+      err = GetStore()->StringToToken(GetEnv(), kAllThreadsTableKind,
+                                      &m_allThreadsTableKindToken);
+      err = GetStore()->StringToToken(GetEnv(), kThreadHdrsScope,
+                                      &m_threadRowScopeToken);
+      err = GetStore()->StringToToken(GetEnv(), kThreadParentColumnName,
+                                      &m_threadParentColumnToken);
+      err = GetStore()->StringToToken(GetEnv(), kThreadRootColumnName,
+                                      &m_threadRootKeyColumnToken);
+      err = GetStore()->StringToToken(GetEnv(), kOfflineMsgOffsetColumnName,
+                                      &m_offlineMsgOffsetColumnToken);
+      err = GetStore()->StringToToken(GetEnv(), kOfflineMsgSizeColumnName,
+                                      &m_offlineMessageSizeColumnToken);
+
+      if (NS_SUCCEEDED(err)) {
+        // The table of all message hdrs will have table id 1.
+        gAllMsgHdrsTableOID.mOid_Scope = m_hdrRowScopeToken;
+        gAllMsgHdrsTableOID.mOid_Id = kAllMsgHdrsTableKey;
+        gAllThreadsTableOID.mOid_Scope = m_threadRowScopeToken;
+        gAllThreadsTableOID.mOid_Id = kAllThreadsTableKey;
+      }
+    }
+  }
+  return err;
+}
+
+// Returns if the db contains this key
+NS_IMETHODIMP nsMsgDatabase::ContainsKey(nsMsgKey key, bool* containsKey) {
+  nsresult err = NS_OK;
+  mdb_bool hasOid;
+  mdbOid rowObjectId;
+
+  if (!containsKey || !m_mdbAllMsgHeadersTable) return NS_ERROR_NULL_POINTER;
+  *containsKey = false;
+
+  rowObjectId.mOid_Id = key;
+  rowObjectId.mOid_Scope = m_hdrRowScopeToken;
+  err = m_mdbAllMsgHeadersTable->HasOid(GetEnv(), &rowObjectId, &hasOid);
+  if (NS_SUCCEEDED(err)) *containsKey = hasOid;
+
+  return err;
+}
+
+// get a message header for the given key. Caller must release()!
+NS_IMETHODIMP nsMsgDatabase::GetMsgHdrForKey(nsMsgKey key,
+                                             nsIMsgDBHdr** pmsgHdr) {
+  *pmsgHdr = nullptr;
+  NS_ENSURE_ARG_POINTER(pmsgHdr);
+  NS_ENSURE_STATE(m_folder);
+  NS_ENSURE_STATE(m_mdbAllMsgHeadersTable);
+  NS_ENSURE_STATE(m_mdbStore);
+
+  // Because this may be called a lot, and we don't want gettimeofday() to show
+  // up in trace logs, we just remember the most recent time any db was used,
+  // which should be close enough for our purposes.
+  m_lastUseTime = gLastUseTime;
+
+  nsresult rv = GetHdrFromUseCache(key, pmsgHdr);
+  if (NS_SUCCEEDED(rv) && *pmsgHdr) return rv;
+
+  mdbOid rowObjectId;
+  rowObjectId.mOid_Id = key;
+  rowObjectId.mOid_Scope = m_hdrRowScopeToken;
+  mdb_bool hasOid;
+  rv = m_mdbAllMsgHeadersTable->HasOid(GetEnv(), &rowObjectId, &hasOid);
+  if (NS_SUCCEEDED(rv) /* && hasOid */) {
+    nsIMdbRow* hdrRow;
+    rv = m_mdbStore->GetRow(GetEnv(), &rowObjectId, &hdrRow);
+    if (NS_SUCCEEDED(rv)) {
+      if (!hdrRow) {
+        rv = NS_ERROR_NULL_POINTER;
+      } else {
+        rv = CreateMsgHdr(hdrRow, key, pmsgHdr);
+      }
+    }
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgDatabase::DeleteMessage(nsMsgKey key,
+                                           nsIDBChangeListener* instigator,
+                                           bool commit) {
+  nsCOMPtr<nsIMsgDBHdr> msgHdr;
+  GetMsgHdrForKey(key, getter_AddRefs(msgHdr));
+  if (!msgHdr) return NS_MSG_MESSAGE_NOT_FOUND;
+
+  return DeleteHeader(msgHdr, instigator, commit, true);
+}
+
+NS_IMETHODIMP nsMsgDatabase::DeleteMessages(nsTArray<nsMsgKey> const& nsMsgKeys,
+                                            nsIDBChangeListener* instigator) {
+  nsresult err = NS_OK;
+
+  uint32_t kindex;
+  for (kindex = 0; kindex < nsMsgKeys.Length(); kindex++) {
+    nsMsgKey key = nsMsgKeys[kindex];
+    nsCOMPtr<nsIMsgDBHdr> msgHdr;
+
+    bool hasKey;
+
+    if (NS_SUCCEEDED(ContainsKey(key, &hasKey)) && hasKey) {
+      GetMsgHdrForKey(key, getter_AddRefs(msgHdr));
+      if (!msgHdr) {
+        err = NS_MSG_MESSAGE_NOT_FOUND;
+        break;
+      }
+      err = DeleteHeader(msgHdr, instigator, kindex % 300 == 0, true);
+      if (NS_FAILED(err)) break;
+    }
+  }
+  return err;
+}
+
+nsresult nsMsgDatabase::AdjustExpungedBytesOnDelete(nsIMsgDBHdr* msgHdr) {
+  uint32_t size = 0;
+  (void)msgHdr->GetMessageSize(&size);
+  return m_dbFolderInfo->ChangeExpungedBytes(size);
+}
+
+NS_IMETHODIMP nsMsgDatabase::DeleteHeader(nsIMsgDBHdr* msg,
+                                          nsIDBChangeListener* instigator,
+                                          bool commit, bool notify) {
+  if (!msg) return NS_ERROR_NULL_POINTER;
+
+  nsMsgHdr* msgHdr =
+      static_cast<nsMsgHdr*>(msg);  // closed system, so this is ok
+  nsMsgKey key;
+  (void)msg->GetMessageKey(&key);
+  // only need to do this for mail - will this speed up news expiration?
+  SetHdrFlag(msg, true, nsMsgMessageFlags::Expunged);  // tell mailbox (mail)
+
+  bool hdrWasNew = m_newSet.BinaryIndexOf(key) != m_newSet.NoIndex;
+  m_newSet.RemoveElement(key);
+
+  if (m_dbFolderInfo) {
+    bool isRead;
+    m_dbFolderInfo->ChangeNumMessages(-1);
+    IsRead(key, &isRead);
+    if (!isRead) m_dbFolderInfo->ChangeNumUnreadMessages(-1);
+    AdjustExpungedBytesOnDelete(msg);
+  }
+
+  uint32_t flags;
+  nsMsgKey threadParent;
+
+  // Save off flags and threadparent since they will no longer exist after we
+  // remove the header from the db.
+  if (notify) {
+    (void)msg->GetFlags(&flags);
+    msg->GetThreadParent(&threadParent);
+  }
+
+  RemoveHeaderFromThread(msgHdr);
+  if (notify) {
+    // If deleted hdr was new, restore the new flag on flags
+    // so saved searches will know to reduce their new msg count.
+    if (hdrWasNew) flags |= nsMsgMessageFlags::New;
+    NotifyHdrDeletedAll(msg, threadParent, flags,
+                        instigator);  // tell listeners
+  }
+  //  if (!onlyRemoveFromThread)  // to speed up expiration, try this. But
+  //  really need to do this in RemoveHeaderFromDB
+  nsresult ret = RemoveHeaderFromDB(msgHdr);
+
+  if (commit)
+    Commit(nsMsgDBCommitType::kLargeCommit);  // ### dmb is this a good time to
+                                              // commit?
+  return ret;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::UndoDelete(nsIMsgDBHdr* aMsgHdr) {
+  if (aMsgHdr) {
+    // Force deleted flag, so SetHdrFlag won't bail out because deleted flag
+    // isn't set.
+    uint32_t result;
+    aMsgHdr->OrFlags(nsMsgMessageFlags::Expunged, &result);
+    SetHdrFlag(aMsgHdr, false,
+               nsMsgMessageFlags::Expunged);  // Clear deleted flag in db.
+  }
+  return NS_OK;
+}
+
+nsresult nsMsgDatabase::RemoveHeaderFromThread(nsMsgHdr* msgHdr) {
+  if (!msgHdr) return NS_ERROR_NULL_POINTER;
+  nsresult ret = NS_OK;
+  nsCOMPtr<nsIMsgThread> thread;
+  ret = GetThreadContainingMsgHdr(msgHdr, getter_AddRefs(thread));
+  if (NS_SUCCEEDED(ret) && thread) {
+    ret = thread->RemoveChildHdr(msgHdr, this);
+  }
+  return ret;
+}
+
+NS_IMETHODIMP nsMsgDatabase::RemoveHeaderMdbRow(nsIMsgDBHdr* msg) {
+  NS_ENSURE_ARG_POINTER(msg);
+  nsMsgHdr* msgHdr =
+      static_cast<nsMsgHdr*>(msg);  // closed system, so this is ok
+  return RemoveHeaderFromDB(msgHdr);
+}
+
+// This is a lower level routine which doesn't send notifications or
+// update folder info. One use is when a rule fires moving a header
+// from one db to another, to remove it from the first db.
+
+nsresult nsMsgDatabase::RemoveHeaderFromDB(nsMsgHdr* msgHdr) {
+  if (!msgHdr) return NS_ERROR_NULL_POINTER;
+  nsresult ret = NS_OK;
+
+  RemoveHdrFromCache(msgHdr, nsMsgKey_None);
+  if (UseCorrectThreading()) RemoveMsgRefsFromHash(msgHdr);
+  nsIMdbRow* row = msgHdr->GetMDBRow();
+  if (row) {
+    ret = m_mdbAllMsgHeadersTable->CutRow(GetEnv(), row);
+    row->CutAllColumns(GetEnv());
+  }
+  msgHdr->ClearCachedValues();
+  return ret;
+}
+
+nsresult nsMsgDatabase::IsRead(nsMsgKey key, bool* pRead) {
+  nsCOMPtr<nsIMsgDBHdr> msgHdr;
+  GetMsgHdrForKey(key, getter_AddRefs(msgHdr));
+  if (!msgHdr) return NS_MSG_MESSAGE_NOT_FOUND;
+
+  return IsHeaderRead(msgHdr, pRead);
+}
+
+uint32_t nsMsgDatabase::GetStatusFlags(nsIMsgDBHdr* msgHdr,
+                                       nsMsgMessageFlagType origFlags) {
+  uint32_t statusFlags = origFlags;
+  bool isRead = true;
+
+  nsMsgKey key;
+  (void)msgHdr->GetMessageKey(&key);
+  if ((!m_newSet.IsEmpty() && m_newSet[m_newSet.Length() - 1] == key) ||
+      (m_newSet.BinaryIndexOf(key) != m_newSet.NoIndex))
+    statusFlags |= nsMsgMessageFlags::New;
+  if (NS_SUCCEEDED(IsHeaderRead(msgHdr, &isRead)) && isRead)
+    statusFlags |= nsMsgMessageFlags::Read;
+  return statusFlags;
+}
+
+nsresult nsMsgDatabase::IsHeaderRead(nsIMsgDBHdr* msgHdr, bool* pRead) {
+  if (!msgHdr) return NS_MSG_MESSAGE_NOT_FOUND;
+
+  nsMsgHdr* hdr = static_cast<nsMsgHdr*>(msgHdr);  // closed system, cast ok
+  // can't call GetFlags, because it will be recursive.
+  uint32_t flags;
+  hdr->GetRawFlags(&flags);
+  *pRead = !!(flags & nsMsgMessageFlags::Read);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::IsMarked(nsMsgKey key, bool* pMarked) {
+  nsCOMPtr<nsIMsgDBHdr> msgHdr;
+
+  GetMsgHdrForKey(key, getter_AddRefs(msgHdr));
+  if (!msgHdr) return NS_MSG_MESSAGE_NOT_FOUND;
+
+  uint32_t flags;
+  (void)msgHdr->GetFlags(&flags);
+  *pMarked = !!(flags & nsMsgMessageFlags::Marked);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::IsIgnored(nsMsgKey key, bool* pIgnored) {
+  NS_ENSURE_ARG_POINTER(pIgnored);
+
+  nsCOMPtr<nsIMsgThread> threadHdr;
+
+  nsresult rv = GetThreadForMsgKey(key, getter_AddRefs(threadHdr));
+  // This should be very surprising, but we leave that up to the caller
+  // to determine for now.
+  if (!threadHdr) return NS_MSG_MESSAGE_NOT_FOUND;
+
+  uint32_t threadFlags;
+  threadHdr->GetFlags(&threadFlags);
+  *pIgnored = !!(threadFlags & nsMsgMessageFlags::Ignored);
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgDatabase::IsWatched(nsMsgKey key, bool* pWatched) {
+  NS_ENSURE_ARG_POINTER(pWatched);
+
+  nsCOMPtr<nsIMsgThread> threadHdr;
+
+  nsresult rv = GetThreadForMsgKey(key, getter_AddRefs(threadHdr));
+  // This should be very surprising, but we leave that up to the caller
+  // to determine for now.
+  if (!threadHdr) return NS_MSG_MESSAGE_NOT_FOUND;
+
+  uint32_t threadFlags;
+  threadHdr->GetFlags(&threadFlags);
+  *pWatched = !!(threadFlags & nsMsgMessageFlags::Watched);
+  return rv;
+}
+
+nsresult nsMsgDatabase::HasAttachments(nsMsgKey key, bool* pHasThem) {
+  NS_ENSURE_ARG_POINTER(pHasThem);
+
+  nsCOMPtr<nsIMsgDBHdr> msgHdr;
+
+  GetMsgHdrForKey(key, getter_AddRefs(msgHdr));
+  if (!msgHdr) return NS_MSG_MESSAGE_NOT_FOUND;
+
+  uint32_t flags;
+  (void)msgHdr->GetFlags(&flags);
+  *pHasThem = !!(flags & nsMsgMessageFlags::Attachment);
+  return NS_OK;
+}
+
+bool nsMsgDatabase::SetHdrReadFlag(nsIMsgDBHdr* msgHdr, bool bRead) {
+  return SetHdrFlag(msgHdr, bRead, nsMsgMessageFlags::Read);
+}
+
+nsresult nsMsgDatabase::MarkHdrReadInDB(nsIMsgDBHdr* msgHdr, bool bRead,
+                                        nsIDBChangeListener* instigator) {
+  nsresult rv;
+  nsMsgKey key;
+  uint32_t oldFlags;
+  bool hdrInDB;
+  (void)msgHdr->GetMessageKey(&key);
+  msgHdr->GetFlags(&oldFlags);
+
+  m_newSet.RemoveElement(key);
+  (void)ContainsKey(key, &hdrInDB);
+  if (hdrInDB && m_dbFolderInfo) {
+    if (bRead)
+      m_dbFolderInfo->ChangeNumUnreadMessages(-1);
+    else
+      m_dbFolderInfo->ChangeNumUnreadMessages(1);
+  }
+
+  SetHdrReadFlag(msgHdr, bRead);  // this will cause a commit, at least for
+                                  // local mail, so do it after we change
+  // the folder counts above, so they will get committed too.
+  uint32_t flags;
+  rv = msgHdr->GetFlags(&flags);
+  flags &= ~nsMsgMessageFlags::New;
+  msgHdr->SetFlags(flags);
+  if (NS_FAILED(rv)) return rv;
+
+  if (oldFlags == flags) return NS_OK;
+
+  return NotifyHdrChangeAll(msgHdr, oldFlags, flags, instigator);
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkRead(nsMsgKey key, bool bRead,
+                                      nsIDBChangeListener* instigator) {
+  nsCOMPtr<nsIMsgDBHdr> msgHdr;
+
+  GetMsgHdrForKey(key, getter_AddRefs(msgHdr));
+  if (!msgHdr) return NS_MSG_MESSAGE_NOT_FOUND;
+
+  return MarkHdrRead(msgHdr, bRead, instigator);
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkReplied(
+    nsMsgKey key, bool bReplied, nsIDBChangeListener* instigator /* = NULL */) {
+  return SetKeyFlag(key, bReplied, nsMsgMessageFlags::Replied, instigator);
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkForwarded(
+    nsMsgKey key, bool bForwarded,
+    nsIDBChangeListener* instigator /* = NULL */) {
+  return SetKeyFlag(key, bForwarded, nsMsgMessageFlags::Forwarded, instigator);
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkRedirected(
+    nsMsgKey key, bool bRedirected,
+    nsIDBChangeListener* instigator /* = NULL */) {
+  return SetKeyFlag(key, bRedirected, nsMsgMessageFlags::Redirected,
+                    instigator);
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkHasAttachments(
+    nsMsgKey key, bool bHasAttachments, nsIDBChangeListener* instigator) {
+  return SetKeyFlag(key, bHasAttachments, nsMsgMessageFlags::Attachment,
+                    instigator);
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::MarkThreadRead(nsIMsgThread* thread,
+                              nsIDBChangeListener* instigator,
+                              nsTArray<nsMsgKey>& aThoseMarkedRead) {
+  NS_ENSURE_ARG_POINTER(thread);
+  aThoseMarkedRead.ClearAndRetainStorage();
+  nsresult rv = NS_OK;
+
+  uint32_t numChildren;
+  thread->GetNumChildren(&numChildren);
+  aThoseMarkedRead.SetCapacity(numChildren);
+  for (uint32_t curChildIndex = 0; curChildIndex < numChildren;
+       curChildIndex++) {
+    nsCOMPtr<nsIMsgDBHdr> child;
+
+    rv = thread->GetChildHdrAt(curChildIndex, getter_AddRefs(child));
+    if (NS_SUCCEEDED(rv) && child) {
+      bool isRead = true;
+      IsHeaderRead(child, &isRead);
+      if (!isRead) {
+        nsMsgKey key;
+        if (NS_SUCCEEDED(child->GetMessageKey(&key)))
+          aThoseMarkedRead.AppendElement(key);
+        MarkHdrRead(child, true, instigator);
+      }
+    }
+  }
+  return rv;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::MarkThreadIgnored(nsIMsgThread* thread, nsMsgKey threadKey,
+                                 bool bIgnored,
+                                 nsIDBChangeListener* instigator) {
+  NS_ENSURE_ARG(thread);
+  uint32_t threadFlags;
+  thread->GetFlags(&threadFlags);
+  uint32_t oldThreadFlags =
+      threadFlags;  // not quite right, since we probably want msg hdr flags.
+  if (bIgnored) {
+    threadFlags |= nsMsgMessageFlags::Ignored;
+    threadFlags &= ~nsMsgMessageFlags::Watched;  // ignore is implicit un-watch
+  } else
+    threadFlags &= ~nsMsgMessageFlags::Ignored;
+  thread->SetFlags(threadFlags);
+
+  nsCOMPtr<nsIMsgDBHdr> msg;
+  GetMsgHdrForKey(threadKey, getter_AddRefs(msg));
+  NS_ENSURE_TRUE(msg, NS_MSG_MESSAGE_NOT_FOUND);
+
+  // We'll add the message flags to the thread flags when notifying, since
+  // notifications are supposed to be about messages, not threads.
+  uint32_t msgFlags;
+  msg->GetFlags(&msgFlags);
+
+  return NotifyHdrChangeAll(msg, oldThreadFlags | msgFlags,
+                            threadFlags | msgFlags, instigator);
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::MarkHeaderKilled(nsIMsgDBHdr* msg, bool bIgnored,
+                                nsIDBChangeListener* instigator) {
+  uint32_t msgFlags;
+  msg->GetFlags(&msgFlags);
+  uint32_t oldFlags = msgFlags;
+  if (bIgnored)
+    msgFlags |= nsMsgMessageFlags::Ignored;
+  else
+    msgFlags &= ~nsMsgMessageFlags::Ignored;
+  msg->SetFlags(msgFlags);
+
+  return NotifyHdrChangeAll(msg, oldFlags, msgFlags, instigator);
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::MarkThreadWatched(nsIMsgThread* thread, nsMsgKey threadKey,
+                                 bool bWatched,
+                                 nsIDBChangeListener* instigator) {
+  NS_ENSURE_ARG(thread);
+  uint32_t threadFlags;
+  thread->GetFlags(&threadFlags);
+  uint32_t oldThreadFlags =
+      threadFlags;  // not quite right, since we probably want msg hdr flags.
+  if (bWatched) {
+    threadFlags |= nsMsgMessageFlags::Watched;
+    threadFlags &= ~nsMsgMessageFlags::Ignored;  // watch is implicit un-ignore
+  } else
+    threadFlags &= ~nsMsgMessageFlags::Watched;
+  thread->SetFlags(threadFlags);
+
+  nsCOMPtr<nsIMsgDBHdr> msg;
+  GetMsgHdrForKey(threadKey, getter_AddRefs(msg));
+  if (!msg) return NS_MSG_MESSAGE_NOT_FOUND;
+
+  // We'll add the message flags to the thread flags when notifying, since
+  // notifications are supposed to be about messages, not threads.
+  uint32_t msgFlags;
+  msg->GetFlags(&msgFlags);
+
+  return NotifyHdrChangeAll(msg, oldThreadFlags | msgFlags,
+                            threadFlags | msgFlags, instigator);
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkMarked(nsMsgKey key, bool mark,
+                                        nsIDBChangeListener* instigator) {
+  return SetKeyFlag(key, mark, nsMsgMessageFlags::Marked, instigator);
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkOffline(nsMsgKey key, bool offline,
+                                         nsIDBChangeListener* instigator) {
+  return SetKeyFlag(key, offline, nsMsgMessageFlags::Offline, instigator);
+}
+
+NS_IMETHODIMP nsMsgDatabase::SetStringProperty(nsMsgKey aKey,
+                                               const char* aProperty,
+                                               const nsACString& aValue) {
+  nsCOMPtr<nsIMsgDBHdr> msgHdr;
+  GetMsgHdrForKey(aKey, getter_AddRefs(msgHdr));
+  if (!msgHdr) return NS_MSG_MESSAGE_NOT_FOUND;
+  return SetStringPropertyByHdr(msgHdr, aProperty, aValue);
+}
+
+NS_IMETHODIMP nsMsgDatabase::SetStringPropertyByHdr(nsIMsgDBHdr* msgHdr,
+                                                    const char* aProperty,
+                                                    const nsACString& aValue) {
+  // don't do notifications if message not yet added to database.
+  // Ignore errors (consequences of failure are minor).
+  bool notify = true;
+  nsMsgKey key = nsMsgKey_None;
+  msgHdr->GetMessageKey(&key);
+  ContainsKey(key, &notify);
+
+  nsCString oldValue;
+  nsresult rv = msgHdr->GetStringProperty(aProperty, oldValue);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // if no change to this string property, bail out
+  if (oldValue.Equals(aValue)) return NS_OK;
+
+  // Precall OnHdrPropertyChanged to store prechange status
+  nsTArray<uint32_t> statusArray(m_ChangeListeners.Length());
+  nsCOMPtr<nsIDBChangeListener> listener;
+  if (notify) {
+    nsTObserverArray<nsCOMPtr<nsIDBChangeListener>>::ForwardIterator listeners(
+        m_ChangeListeners);
+    while (listeners.HasMore()) {
+      listener = listeners.GetNext();
+      // initialize |status| because some implementations of
+      // OnHdrPropertyChanged does not set the value.
+      uint32_t status = 0;
+      (void)listener->OnHdrPropertyChanged(msgHdr, nsCString(aProperty), true,
+                                           &status, nullptr);
+      // ignore errors, but append element to keep arrays in sync
+      statusArray.AppendElement(status);
+    }
+  }
+
+  rv = msgHdr->SetStringProperty(aProperty, aValue);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Postcall OnHdrPropertyChanged to process the change
+  if (notify) {
+    // if this is the junk score property notify, as long as we're not going
+    // from no value to non junk
+    if (!strcmp(aProperty, "junkscore") &&
+        !(oldValue.IsEmpty() && aValue.Equals("0")))
+      NotifyJunkScoreChanged(nullptr);
+
+    nsTObserverArray<nsCOMPtr<nsIDBChangeListener>>::ForwardIterator listeners(
+        m_ChangeListeners);
+    for (uint32_t i = 0; listeners.HasMore() && i < statusArray.Length(); i++) {
+      listener = listeners.GetNext();
+      uint32_t status = statusArray[i];
+      (void)listener->OnHdrPropertyChanged(msgHdr, nsCString(aProperty), false,
+                                           &status, nullptr);
+      // ignore errors
+    }
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::SetUint32PropertyByHdr(nsIMsgDBHdr* aMsgHdr,
+                                      const char* aProperty, uint32_t aValue) {
+  // If no change to this property, bail out.
+  uint32_t oldValue;
+  nsresult rv = aMsgHdr->GetUint32Property(aProperty, &oldValue);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (oldValue == aValue) return NS_OK;
+
+  // Don't do notifications if message not yet added to database.
+  bool notify = true;
+  nsMsgKey key = nsMsgKey_None;
+  aMsgHdr->GetMessageKey(&key);
+  ContainsKey(key, &notify);
+
+  // Precall OnHdrPropertyChanged to store prechange status.
+  nsTArray<uint32_t> statusArray(m_ChangeListeners.Length());
+  nsCOMPtr<nsIDBChangeListener> listener;
+  if (notify) {
+    nsTObserverArray<nsCOMPtr<nsIDBChangeListener>>::ForwardIterator listeners(
+        m_ChangeListeners);
+    while (listeners.HasMore()) {
+      listener = listeners.GetNext();
+      // initialize |status| because some implementations of
+      // OnHdrPropertyChanged does not set the value.
+      uint32_t status = 0;
+      (void)listener->OnHdrPropertyChanged(aMsgHdr, nsCString(aProperty), true,
+                                           &status, nullptr);
+      // Ignore errors, but append element to keep arrays in sync.
+      statusArray.AppendElement(status);
+    }
+  }
+
+  rv = aMsgHdr->SetUint32Property(aProperty, aValue);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Postcall OnHdrPropertyChanged to process the change.
+  if (notify) {
+    nsTObserverArray<nsCOMPtr<nsIDBChangeListener>>::ForwardIterator listeners(
+        m_ChangeListeners);
+    for (uint32_t i = 0; listeners.HasMore(); i++) {
+      listener = listeners.GetNext();
+      uint32_t status = statusArray[i];
+      (void)listener->OnHdrPropertyChanged(aMsgHdr, nsCString(aProperty), false,
+                                           &status, nullptr);
+      // Ignore errors.
+    }
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkImapDeleted(nsMsgKey key, bool deleted,
+                                             nsIDBChangeListener* instigator) {
+  return SetKeyFlag(key, deleted, nsMsgMessageFlags::IMAPDeleted, instigator);
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkMDNNeeded(
+    nsMsgKey key, bool bNeeded, nsIDBChangeListener* instigator /* = NULL */) {
+  return SetKeyFlag(key, bNeeded, nsMsgMessageFlags::MDNReportNeeded,
+                    instigator);
+}
+
+nsresult nsMsgDatabase::MarkMDNSent(
+    nsMsgKey key, bool bSent, nsIDBChangeListener* instigator /* = NULL */) {
+  return SetKeyFlag(key, bSent, nsMsgMessageFlags::MDNReportSent, instigator);
+}
+
+nsresult nsMsgDatabase::IsMDNSent(nsMsgKey key, bool* pSent) {
+  nsCOMPtr<nsIMsgDBHdr> msgHdr;
+
+  GetMsgHdrForKey(key, getter_AddRefs(msgHdr));
+  if (!msgHdr) return NS_MSG_MESSAGE_NOT_FOUND;
+
+  uint32_t flags;
+  (void)msgHdr->GetFlags(&flags);
+  *pSent = !!(flags & nsMsgMessageFlags::MDNReportSent);
+  return NS_OK;
+}
+
+nsresult nsMsgDatabase::SetKeyFlag(nsMsgKey key, bool set,
+                                   nsMsgMessageFlagType flag,
+                                   nsIDBChangeListener* instigator) {
+  nsCOMPtr<nsIMsgDBHdr> msgHdr;
+
+  GetMsgHdrForKey(key, getter_AddRefs(msgHdr));
+  if (!msgHdr) return NS_MSG_MESSAGE_NOT_FOUND;
+
+  return SetMsgHdrFlag(msgHdr, set, flag, instigator);
+}
+
+nsresult nsMsgDatabase::SetMsgHdrFlag(nsIMsgDBHdr* msgHdr, bool set,
+                                      nsMsgMessageFlagType flag,
+                                      nsIDBChangeListener* instigator) {
+  uint32_t oldFlags;
+  (void)msgHdr->GetFlags(&oldFlags);
+
+  if (!SetHdrFlag(msgHdr, set, flag)) return NS_OK;
+
+  uint32_t flags;
+  (void)msgHdr->GetFlags(&flags);
+
+  return NotifyHdrChangeAll(msgHdr, oldFlags, flags, instigator);
+}
+
+// Helper routine - lowest level of flag setting - returns true if flags change,
+// false otherwise.
+bool nsMsgDatabase::SetHdrFlag(nsIMsgDBHdr* msgHdr, bool bSet,
+                               nsMsgMessageFlagType flag) {
+  uint32_t statusFlags;
+  (void)msgHdr->GetFlags(&statusFlags);
+  uint32_t currentStatusFlags = GetStatusFlags(msgHdr, statusFlags);
+  bool flagAlreadySet = (currentStatusFlags & flag) != 0;
+
+  if ((flagAlreadySet && !bSet) || (!flagAlreadySet && bSet)) {
+    uint32_t resultFlags;
+    if (bSet)
+      msgHdr->OrFlags(flag, &resultFlags);
+    else
+      msgHdr->AndFlags(~flag, &resultFlags);
+    return true;
+  }
+  return false;
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkHdrRead(nsIMsgDBHdr* msgHdr, bool bRead,
+                                         nsIDBChangeListener* instigator) {
+  bool isReadInDB = true;
+  nsresult rv = nsMsgDatabase::IsHeaderRead(msgHdr, &isReadInDB);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool isRead = true;
+  rv = IsHeaderRead(msgHdr, &isRead);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // if the flag is already correct in the db, don't change it.
+  // Check msg flags as well as IsHeaderRead in case it's a newsgroup
+  // and the msghdr flags are out of sync with the newsrc settings.
+  // (we could override this method for news db's, but it's a trivial fix here.
+  if (bRead != isRead || isRead != isReadInDB) {
+    nsMsgKey msgKey;
+    msgHdr->GetMessageKey(&msgKey);
+
+    bool inDB = false;
+    (void)ContainsKey(msgKey, &inDB);
+
+    if (inDB) {
+      nsCOMPtr<nsIMsgThread> threadHdr;
+      rv = GetThreadForMsgKey(msgKey, getter_AddRefs(threadHdr));
+      if (threadHdr) threadHdr->MarkChildRead(bRead);
+    }
+
+#ifndef MOZ_SUITE
+    if (bRead) {
+      Telemetry::ScalarAdd(Telemetry::ScalarID::TB_MAILS_READ, 1);
+    }
+#endif
+
+    return MarkHdrReadInDB(msgHdr, bRead, instigator);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkHdrReplied(nsIMsgDBHdr* msgHdr, bool bReplied,
+                                            nsIDBChangeListener* instigator) {
+  return SetMsgHdrFlag(msgHdr, bReplied, nsMsgMessageFlags::Replied,
+                       instigator);
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkHdrMarked(nsIMsgDBHdr* msgHdr, bool mark,
+                                           nsIDBChangeListener* instigator) {
+  return SetMsgHdrFlag(msgHdr, mark, nsMsgMessageFlags::Marked, instigator);
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::MarkHdrNotNew(nsIMsgDBHdr* aMsgHdr,
+                             nsIDBChangeListener* aInstigator) {
+  NS_ENSURE_ARG_POINTER(aMsgHdr);
+  nsMsgKey msgKey;
+  aMsgHdr->GetMessageKey(&msgKey);
+  m_newSet.RemoveElement(msgKey);
+  return SetMsgHdrFlag(aMsgHdr, false, nsMsgMessageFlags::New, aInstigator);
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkAllRead(nsTArray<nsMsgKey>& aThoseMarked) {
+  aThoseMarked.ClearAndRetainStorage();
+
+  nsCOMPtr<nsIMsgEnumerator> hdrs;
+  nsresult rv = EnumerateMessages(getter_AddRefs(hdrs));
+  NS_ENSURE_SUCCESS(rv, rv);
+  bool hasMore = false;
+
+  while (NS_SUCCEEDED(rv = hdrs->HasMoreElements(&hasMore)) && hasMore) {
+    nsCOMPtr<nsIMsgDBHdr> msg;
+    rv = hdrs->GetNext(getter_AddRefs(msg));
+    if (NS_FAILED(rv)) break;
+
+    bool isRead;
+    IsHeaderRead(msg, &isRead);
+
+    if (!isRead) {
+      nsMsgKey key;
+      (void)msg->GetMessageKey(&key);
+      aThoseMarked.AppendElement(key);
+      rv = MarkHdrRead(msg, true, nullptr);  // ### dmb - blow off error?
+    }
+  }
+
+  // force num new to 0.
+  int32_t numUnreadMessages;
+
+  rv = m_dbFolderInfo->GetNumUnreadMessages(&numUnreadMessages);
+  if (NS_SUCCEEDED(rv))
+    m_dbFolderInfo->ChangeNumUnreadMessages(-numUnreadMessages);
+  // caller will Commit the db, so no need to do it here.
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgDatabase::AddToNewList(nsMsgKey key) {
+  // we add new keys in increasing order...
+  if (m_newSet.IsEmpty() || (m_newSet[m_newSet.Length() - 1] < key))
+    m_newSet.AppendElement(key);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::ClearNewList(bool notify /* = FALSE */) {
+  if (notify && !m_newSet.IsEmpty())  // need to update view
+  {
+    nsTArray<nsMsgKey> saveNewSet;
+    // clear m_newSet so that the code that's listening to the key change
+    // doesn't think we have new messages and send notifications all over
+    // that we have new messages.
+    saveNewSet.SwapElements(m_newSet);
+    for (uint32_t elementIndex = saveNewSet.Length() - 1;; elementIndex--) {
+      nsMsgKey lastNewKey = saveNewSet.ElementAt(elementIndex);
+      nsCOMPtr<nsIMsgDBHdr> msgHdr;
+      GetMsgHdrForKey(lastNewKey, getter_AddRefs(msgHdr));
+      if (msgHdr) {
+        uint32_t flags;
+        (void)msgHdr->GetFlags(&flags);
+
+        if ((flags | nsMsgMessageFlags::New) != flags) {
+          msgHdr->AndFlags(~nsMsgMessageFlags::New, &flags);
+          NotifyHdrChangeAll(msgHdr, flags | nsMsgMessageFlags::New, flags,
+                             nullptr);
+        }
+      }
+      if (elementIndex == 0) break;
+    }
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::HasNew(bool* _retval) {
+  if (!_retval) return NS_ERROR_NULL_POINTER;
+
+  *_retval = (m_newSet.Length() > 0);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetFirstNew(nsMsgKey* result) {
+  bool hasnew;
+  nsresult rv = HasNew(&hasnew);
+  if (NS_FAILED(rv)) return rv;
+  *result = (hasnew) ? m_newSet.ElementAt(0) : nsMsgKey_None;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::EnumerateMessages(nsIMsgEnumerator** result) {
+  RememberLastUseTime();
+  NS_ENSURE_ARG_POINTER(result);
+  NS_ADDREF(*result = new nsMsgDBEnumerator(this, m_mdbAllMsgHeadersTable,
+                                            nullptr, nullptr));
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::ReverseEnumerateMessages(nsIMsgEnumerator** result) {
+  NS_ENSURE_ARG_POINTER(result);
+  NS_ADDREF(*result = new nsMsgDBEnumerator(this, m_mdbAllMsgHeadersTable,
+                                            nullptr, nullptr, false));
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::GetFilterEnumerator(
+    const nsTArray<RefPtr<nsIMsgSearchTerm>>& searchTerms, bool aReverse,
+    nsIMsgEnumerator** aResult) {
+  NS_ENSURE_ARG_POINTER(aResult);
+  RefPtr<nsMsgFilteredDBEnumerator> e =
+      new nsMsgFilteredDBEnumerator(this, m_mdbAllMsgHeadersTable, aReverse);
+
+  NS_ENSURE_TRUE(e, NS_ERROR_OUT_OF_MEMORY);
+  nsresult rv = e->InitSearchSession(searchTerms, m_folder);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  e.forget(aResult);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::SyncCounts() {
+  nsCOMPtr<nsIMsgEnumerator> hdrs;
+  nsresult rv = EnumerateMessages(getter_AddRefs(hdrs));
+  if (NS_FAILED(rv)) return rv;
+  bool hasMore = false;
+
+  mdb_count numHdrsInTable = 0;
+  int32_t numUnread = 0;
+  int32_t numHdrs = 0;
+
+  if (m_mdbAllMsgHeadersTable)
+    m_mdbAllMsgHeadersTable->GetCount(GetEnv(), &numHdrsInTable);
+  else
+    return NS_ERROR_NULL_POINTER;
+
+  while (NS_SUCCEEDED(rv = hdrs->HasMoreElements(&hasMore)) && hasMore) {
+    nsCOMPtr<nsIMsgDBHdr> header;
+    rv = hdrs->GetNext(getter_AddRefs(header));
+    NS_ASSERTION(NS_SUCCEEDED(rv), "nsMsgDBEnumerator broken");
+    if (NS_FAILED(rv)) break;
+
+    bool isRead;
+    IsHeaderRead(header, &isRead);
+    if (!isRead) numUnread++;
+    numHdrs++;
+  }
+
+  int32_t oldTotal, oldUnread;
+  (void)m_dbFolderInfo->GetNumUnreadMessages(&oldUnread);
+  (void)m_dbFolderInfo->GetNumMessages(&oldTotal);
+  if (oldUnread != numUnread)
+    m_dbFolderInfo->ChangeNumUnreadMessages(numUnread - oldUnread);
+  if (oldTotal != numHdrs)
+    m_dbFolderInfo->ChangeNumMessages(numHdrs - oldTotal);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::ListAllKeys(nsTArray<nsMsgKey>& keys) {
+  nsresult rv = NS_OK;
+  nsCOMPtr<nsIMdbTableRowCursor> rowCursor;
+  RememberLastUseTime();
+  keys.Clear();
+
+  if (m_mdbAllMsgHeadersTable) {
+    uint32_t numMsgs = 0;
+    m_mdbAllMsgHeadersTable->GetCount(GetEnv(), &numMsgs);
+    keys.SetCapacity(numMsgs);
+    rv = m_mdbAllMsgHeadersTable->GetTableRowCursor(GetEnv(), -1,
+                                                    getter_AddRefs(rowCursor));
+    while (NS_SUCCEEDED(rv) && rowCursor) {
+      mdbOid outOid;
+      mdb_pos outPos;
+
+      rv = rowCursor->NextRowOid(GetEnv(), &outOid, &outPos);
+      // is this right? Mork is returning a 0 id, but that should valid.
+      if (outPos < 0 || outOid.mOid_Id == (mdb_id)-1) break;
+      if (NS_SUCCEEDED(rv)) keys.AppendElement(outOid.mOid_Id);
+    }
+  }
+  return rv;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::EnumerateThreads(nsIMsgThreadEnumerator** result) {
+  RememberLastUseTime();
+  NS_ADDREF(*result = new nsMsgDBThreadEnumerator(this, nullptr));
+  return NS_OK;
+}
+
+// only return headers with a particular flag set
+static nsresult nsMsgFlagSetFilter(nsIMsgDBHdr* msg, void* closure) {
+  uint32_t msgFlags, desiredFlags;
+  desiredFlags = *(uint32_t*)closure;
+  msg->GetFlags(&msgFlags);
+  return (msgFlags & desiredFlags) ? NS_OK : NS_ERROR_FAILURE;
+}
+
+nsresult nsMsgDatabase::EnumerateMessagesWithFlag(nsIMsgEnumerator** result,
+                                                  uint32_t* pFlag) {
+  RememberLastUseTime();
+  NS_ADDREF(*result = new nsMsgDBEnumerator(this, m_mdbAllMsgHeadersTable,
+                                            nsMsgFlagSetFilter, pFlag));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::CreateNewHdr(nsMsgKey key, nsIMsgDBHdr** pnewHdr) {
+  nsresult err = NS_OK;
+  nsIMdbRow* hdrRow = nullptr;
+  struct mdbOid allMsgHdrsTableOID;
+
+  if (!pnewHdr || !m_mdbAllMsgHeadersTable || !m_mdbStore)
+    return NS_ERROR_NULL_POINTER;
+
+  if (key != nsMsgKey_None) {
+    allMsgHdrsTableOID.mOid_Scope = m_hdrRowScopeToken;
+    allMsgHdrsTableOID.mOid_Id = key;  // presumes 0 is valid key value
+
+    err = m_mdbStore->GetRow(GetEnv(), &allMsgHdrsTableOID, &hdrRow);
+    if (!hdrRow)
+      err = m_mdbStore->NewRowWithOid(GetEnv(), &allMsgHdrsTableOID, &hdrRow);
+  } else {
+    // Mork will assign an ID to the new row, generally the next available ID.
+    err = m_mdbStore->NewRow(GetEnv(), m_hdrRowScopeToken, &hdrRow);
+    if (hdrRow) {
+      struct mdbOid oid;
+      hdrRow->GetOid(GetEnv(), &oid);
+      key = oid.mOid_Id;
+    } else {
+      // We failed to create a new row. That can happen if we run out of keys,
+      // which will force a reparse.
+      nsTArray<nsMsgKey> keys;
+      if (NS_SUCCEEDED(ListAllKeys(keys))) {
+        for (nsMsgKey key : keys) {
+          if (key >= kForceReparseKey) {
+            // Force a reparse.
+            if (m_dbFolderInfo)
+              m_dbFolderInfo->SetBooleanProperty("forceReparse", true);
+            break;
+          }
+        }
+      }
+      err = NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE;
+    }
+  }
+  if (NS_FAILED(err)) return err;
+  err = CreateMsgHdr(hdrRow, key, pnewHdr);
+  return err;
+}
+
+NS_IMETHODIMP nsMsgDatabase::AddNewHdrToDB(nsIMsgDBHdr* newHdr, bool notify) {
+  NS_ENSURE_ARG_POINTER(newHdr);
+  nsMsgHdr* hdr = static_cast<nsMsgHdr*>(newHdr);  // closed system, cast ok
+  bool newThread;
+  bool hasKey = false;
+  nsMsgKey msgKey = nsMsgKey_None;
+  (void)hdr->GetMessageKey(&msgKey);
+  (void)ContainsKey(msgKey, &hasKey);
+  if (hasKey) {
+    NS_ERROR("adding hdr that already exists");
+    return NS_ERROR_FAILURE;
+  }
+  nsresult err = ThreadNewHdr(hdr, newThread);
+  // we thread header before we add it to the all headers table
+  // so that subject and reference threading will work (otherwise,
+  // when we try to find the first header with the same subject or
+  // reference, we get the new header!)
+  if (NS_SUCCEEDED(err)) {
+    nsMsgKey key;
+    uint32_t flags;
+
+    newHdr->GetMessageKey(&key);
+    hdr->GetRawFlags(&flags);
+    // use raw flags instead of GetFlags, because GetFlags will
+    // pay attention to what's in m_newSet, and this new hdr isn't
+    // in m_newSet yet.
+    if (flags & nsMsgMessageFlags::New) {
+      uint32_t newFlags;
+      newHdr->AndFlags(~nsMsgMessageFlags::New,
+                       &newFlags);  // make sure not filed out
+      AddToNewList(key);
+    }
+    if (m_dbFolderInfo) {
+      m_dbFolderInfo->ChangeNumMessages(1);
+      bool isRead = true;
+      IsHeaderRead(newHdr, &isRead);
+      if (!isRead) m_dbFolderInfo->ChangeNumUnreadMessages(1);
+      m_dbFolderInfo->OnKeyAdded(key);
+    }
+
+    err = m_mdbAllMsgHeadersTable->AddRow(GetEnv(), hdr->GetMDBRow());
+    if (notify) {
+      nsMsgKey threadParent;
+
+      newHdr->GetThreadParent(&threadParent);
+      NotifyHdrAddedAll(newHdr, threadParent, flags, NULL);
+    }
+
+    if (UseCorrectThreading()) err = AddMsgRefsToHash(newHdr);
+  }
+  NS_ASSERTION(NS_SUCCEEDED(err), "error creating thread");
+  return err;
+}
+
+NS_IMETHODIMP nsMsgDatabase::CopyHdrFromExistingHdr(nsMsgKey key,
+                                                    nsIMsgDBHdr* existingHdr,
+                                                    bool addHdrToDB,
+                                                    nsIMsgDBHdr** newHdr) {
+  nsresult err = NS_OK;
+
+  if (existingHdr) {
+    nsMsgHdr* sourceMsgHdr =
+        static_cast<nsMsgHdr*>(existingHdr);  // closed system, cast ok
+    nsMsgHdr* destMsgHdr = nullptr;
+    CreateNewHdr(key, (nsIMsgDBHdr**)&destMsgHdr);
+    nsIMdbRow* sourceRow = sourceMsgHdr->GetMDBRow();
+    if (!destMsgHdr || !sourceRow) return NS_MSG_MESSAGE_NOT_FOUND;
+
+    nsIMdbRow* destRow = destMsgHdr->GetMDBRow();
+    if (!destRow) return NS_ERROR_UNEXPECTED;
+
+    err = destRow->SetRow(GetEnv(), sourceRow);
+    if (NS_SUCCEEDED(err)) {
+      // we may have gotten the header from a cache - calling SetRow
+      // basically invalidates any cached values, so invalidate them.
+      destMsgHdr->ClearCachedValues();
+      if (addHdrToDB) err = AddNewHdrToDB(destMsgHdr, true);
+      if (NS_SUCCEEDED(err) && newHdr) *newHdr = destMsgHdr;
+    }
+  }
+  return err;
+}
+
+nsresult nsMsgDatabase::RowCellColumnTonsString(nsIMdbRow* hdrRow,
+                                                mdb_token columnToken,
+                                                nsAString& resultStr) {
+  NS_ENSURE_ARG_POINTER(hdrRow);
+
+  struct mdbYarn yarn;
+  nsresult rv = hdrRow->AliasCellYarn(GetEnv(), columnToken, &yarn);
+  NS_ENSURE_SUCCESS(rv, rv);
+  YarnTonsString(&yarn, resultStr);
+  return NS_OK;
+}
+
+// as long as the row still exists, and isn't changed, the returned const char
+// ** will be valid. But be very careful using this data - the caller should
+// never return it in turn to another caller.
+nsresult nsMsgDatabase::RowCellColumnToConstCharPtr(nsIMdbRow* hdrRow,
+                                                    mdb_token columnToken,
+                                                    const char** ptr) {
+  NS_ENSURE_ARG_POINTER(hdrRow);
+
+  struct mdbYarn yarn;
+  nsresult rv = hdrRow->AliasCellYarn(GetEnv(), columnToken, &yarn);
+  NS_ENSURE_SUCCESS(rv, rv);
+  *ptr = (const char*)yarn.mYarn_Buf;
+  return NS_OK;
+}
+
+nsIMimeConverter* nsMsgDatabase::GetMimeConverter() {
+  if (!m_mimeConverter) {
+    // apply mime decode
+    m_mimeConverter = do_GetService("@mozilla.org/messenger/mimeconverter;1");
+  }
+  return m_mimeConverter;
+}
+
+nsresult nsMsgDatabase::GetEffectiveCharset(nsIMdbRow* row,
+                                            nsACString& resultCharset) {
+  resultCharset.Truncate();
+  nsresult rv = RowCellColumnToCharPtr(row, m_messageCharSetColumnToken,
+                                       getter_Copies(resultCharset));
+  if (NS_FAILED(rv) || resultCharset.IsEmpty() ||
+      resultCharset.EqualsLiteral("us-ascii")) {
+    resultCharset.AssignLiteral("UTF-8");
+    nsCOMPtr<nsIMsgNewsFolder> newsfolder(do_QueryInterface(m_folder));
+    if (newsfolder) newsfolder->GetCharset(resultCharset);
+  }
+  return rv;
+}
+
+nsresult nsMsgDatabase::RowCellColumnToMime2DecodedString(
+    nsIMdbRow* row, mdb_token columnToken, nsAString& resultStr) {
+  nsresult err = NS_OK;
+  const char* nakedString = nullptr;
+  err = RowCellColumnToConstCharPtr(row, columnToken, &nakedString);
+  if (NS_SUCCEEDED(err) && nakedString && strlen(nakedString)) {
+    GetMimeConverter();
+    if (m_mimeConverter) {
+      nsAutoString decodedStr;
+      nsCString charSet;
+      GetEffectiveCharset(row, charSet);
+
+      err = m_mimeConverter->DecodeMimeHeader(nakedString, charSet.get(), false,
+                                              true, resultStr);
+    }
+  }
+  return err;
+}
+
+nsresult nsMsgDatabase::RowCellColumnToAddressCollationKey(
+    nsIMdbRow* row, mdb_token colToken, nsTArray<uint8_t>& result) {
+  nsString sender;
+  nsresult rv = RowCellColumnToMime2DecodedString(row, colToken, sender);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsString name;
+  ExtractName(DecodedHeader(sender), name);
+  return CreateCollationKey(name, result);
+}
+
+nsresult nsMsgDatabase::GetCollationKeyGenerator() {
+  if (!m_collationKeyGenerator) {
+    auto result = mozilla::intl::LocaleService::TryCreateComponent<Collator>();
+    if (result.isErr()) {
+      NS_WARNING("Could not create mozilla::intl::Collation.");
+      return NS_ERROR_FAILURE;
+    }
+
+    m_collationKeyGenerator = 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 = m_collationKeyGenerator->SetOptions(options);
+
+    if (optResult.isErr()) {
+      NS_WARNING("Could not configure the mozilla::intl::Collation.");
+      m_collationKeyGenerator = nullptr;
+      return NS_ERROR_FAILURE;
+    }
+  }
+  return NS_OK;
+}
+
+nsresult nsMsgDatabase::RowCellColumnToCollationKey(nsIMdbRow* row,
+                                                    mdb_token columnToken,
+                                                    nsTArray<uint8_t>& result) {
+  const char* nakedString = nullptr;
+  nsresult err;
+
+  err = RowCellColumnToConstCharPtr(row, columnToken, &nakedString);
+  if (!nakedString) nakedString = "";
+  if (NS_SUCCEEDED(err)) {
+    GetMimeConverter();
+    if (m_mimeConverter) {
+      nsCString decodedStr;
+      nsCString charSet;
+      GetEffectiveCharset(row, charSet);
+
+      err = m_mimeConverter->DecodeMimeHeaderToUTF8(
+          nsDependentCString(nakedString), charSet.get(), false, true,
+          decodedStr);
+      if (NS_SUCCEEDED(err))
+        err = CreateCollationKey(NS_ConvertUTF8toUTF16(decodedStr), result);
+    }
+  }
+  return err;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::CompareCollationKeys(const nsTArray<uint8_t>& key1,
+                                    const nsTArray<uint8_t>& key2,
+                                    int32_t* result) {
+  nsresult rv = GetCollationKeyGenerator();
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (!m_collationKeyGenerator) return NS_ERROR_FAILURE;
+
+  *result = m_collationKeyGenerator->CompareSortKeys(key1, key2);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::CreateCollationKey(const nsAString& sourceString,
+                                  nsTArray<uint8_t>& key) {
+  nsresult err = GetCollationKeyGenerator();
+  NS_ENSURE_SUCCESS(err, err);
+  if (!m_collationKeyGenerator) return NS_ERROR_FAILURE;
+
+  nsTArrayU8Buffer buffer(key);
+
+  auto result = m_collationKeyGenerator->GetSortKey(sourceString, buffer);
+  NS_ENSURE_TRUE(result.isOk(), NS_ERROR_FAILURE);
+
+  return NS_OK;
+}
+
+nsresult nsMsgDatabase::RowCellColumnToUInt32(nsIMdbRow* hdrRow,
+                                              mdb_token columnToken,
+                                              uint32_t& uint32Result,
+                                              uint32_t defaultValue) {
+  return RowCellColumnToUInt32(hdrRow, columnToken, &uint32Result,
+                               defaultValue);
+}
+
+nsresult nsMsgDatabase::RowCellColumnToUInt32(nsIMdbRow* hdrRow,
+                                              mdb_token columnToken,
+                                              uint32_t* uint32Result,
+                                              uint32_t defaultValue) {
+  nsresult err = NS_OK;
+
+  if (uint32Result) *uint32Result = defaultValue;
+  if (hdrRow)  // ### probably should be an error if hdrRow is NULL...
+  {
+    struct mdbYarn yarn;
+    err = hdrRow->AliasCellYarn(GetEnv(), columnToken, &yarn);
+    if (NS_SUCCEEDED(err)) YarnToUInt32(&yarn, uint32Result);
+  }
+  return err;
+}
+
+nsresult nsMsgDatabase::UInt32ToRowCellColumn(nsIMdbRow* row,
+                                              mdb_token columnToken,
+                                              uint32_t value) {
+  struct mdbYarn yarn;
+  char yarnBuf[100];
+
+  if (!row) return NS_ERROR_NULL_POINTER;
+
+  yarn.mYarn_Buf = (void*)yarnBuf;
+  yarn.mYarn_Size = sizeof(yarnBuf);
+  yarn.mYarn_Fill = yarn.mYarn_Size;
+  yarn.mYarn_Form = 0;
+  yarn.mYarn_Grow = NULL;
+  return row->AddColumn(GetEnv(), columnToken, UInt32ToYarn(&yarn, value));
+}
+
+nsresult nsMsgDatabase::UInt64ToRowCellColumn(nsIMdbRow* row,
+                                              mdb_token columnToken,
+                                              uint64_t value) {
+  NS_ENSURE_ARG_POINTER(row);
+  struct mdbYarn yarn;
+  char yarnBuf[17];  // max string is 16 bytes, + 1 for null.
+
+  yarn.mYarn_Buf = (void*)yarnBuf;
+  yarn.mYarn_Size = sizeof(yarnBuf);
+  yarn.mYarn_Form = 0;
+  yarn.mYarn_Grow = NULL;
+  PR_snprintf((char*)yarn.mYarn_Buf, yarn.mYarn_Size, "%llx", value);
+  yarn.mYarn_Fill = PL_strlen((const char*)yarn.mYarn_Buf);
+  return row->AddColumn(GetEnv(), columnToken, &yarn);
+}
+
+nsresult nsMsgDatabase::RowCellColumnToUInt64(nsIMdbRow* hdrRow,
+                                              mdb_token columnToken,
+                                              uint64_t* uint64Result,
+                                              uint64_t defaultValue) {
+  nsresult err = NS_OK;
+
+  if (uint64Result) *uint64Result = defaultValue;
+  if (hdrRow)  // ### probably should be an error if hdrRow is NULL...
+  {
+    struct mdbYarn yarn;
+    err = hdrRow->AliasCellYarn(GetEnv(), columnToken, &yarn);
+    if (NS_SUCCEEDED(err)) YarnToUInt64(&yarn, uint64Result);
+  }
+  return err;
+}
+
+nsresult nsMsgDatabase::CharPtrToRowCellColumn(nsIMdbRow* row,
+                                               mdb_token columnToken,
+                                               const char* charPtr) {
+  if (!row) return NS_ERROR_NULL_POINTER;
+
+  struct mdbYarn yarn;
+  yarn.mYarn_Buf = (void*)charPtr;
+  yarn.mYarn_Size = PL_strlen((const char*)yarn.mYarn_Buf) + 1;
+  yarn.mYarn_Fill = yarn.mYarn_Size - 1;
+  yarn.mYarn_Form =
+      0;  // what to do with this? we're storing csid in the msg hdr...
+
+  return row->AddColumn(GetEnv(), columnToken, &yarn);
+}
+
+// caller must free result
+nsresult nsMsgDatabase::RowCellColumnToCharPtr(nsIMdbRow* row,
+                                               mdb_token columnToken,
+                                               char** result) {
+  nsresult err = NS_ERROR_NULL_POINTER;
+
+  if (row && result) {
+    struct mdbYarn yarn;
+    err = row->AliasCellYarn(GetEnv(), columnToken, &yarn);
+    if (NS_SUCCEEDED(err)) {
+      *result = (char*)moz_xmalloc(yarn.mYarn_Fill + 1);
+      if (*result) {
+        if (yarn.mYarn_Fill > 0)
+          memcpy(*result, yarn.mYarn_Buf, yarn.mYarn_Fill);
+        (*result)[yarn.mYarn_Fill] = '\0';
+      } else
+        err = NS_ERROR_OUT_OF_MEMORY;
+    }
+  }
+  return err;
+}
+
+/* static */ struct mdbYarn* nsMsgDatabase::nsStringToYarn(
+    struct mdbYarn* yarn, const nsAString& str) {
+  yarn->mYarn_Buf = ToNewCString(NS_ConvertUTF16toUTF8(str));
+  yarn->mYarn_Size = strlen((const char*)yarn->mYarn_Buf) + 1;
+  yarn->mYarn_Fill = yarn->mYarn_Size - 1;
+  yarn->mYarn_Form =
+      0;  // what to do with this? we're storing csid in the msg hdr...
+  return yarn;
+}
+
+/* static */ struct mdbYarn* nsMsgDatabase::UInt32ToYarn(struct mdbYarn* yarn,
+                                                         uint32_t i) {
+  PR_snprintf((char*)yarn->mYarn_Buf, yarn->mYarn_Size, "%lx", i);
+  yarn->mYarn_Fill = PL_strlen((const char*)yarn->mYarn_Buf);
+  yarn->mYarn_Form =
+      0;  // what to do with this? Should be parsed out of the mime2 header?
+  return yarn;
+}
+
+/* static */ struct mdbYarn* nsMsgDatabase::UInt64ToYarn(struct mdbYarn* yarn,
+                                                         uint64_t i) {
+  PR_snprintf((char*)yarn->mYarn_Buf, yarn->mYarn_Size, "%llx", i);
+  yarn->mYarn_Fill = PL_strlen((const char*)yarn->mYarn_Buf);
+  yarn->mYarn_Form = 0;
+  return yarn;
+}
+
+/* static */ void nsMsgDatabase::YarnTonsString(struct mdbYarn* yarn,
+                                                nsAString& str) {
+  const char* buf = (const char*)yarn->mYarn_Buf;
+  if (buf)
+    CopyUTF8toUTF16(Substring(buf, buf + yarn->mYarn_Fill), str);
+  else
+    str.Truncate();
+}
+
+/* static */ void nsMsgDatabase::YarnTonsCString(struct mdbYarn* yarn,
+                                                 nsACString& str) {
+  const char* buf = (const char*)yarn->mYarn_Buf;
+  if (buf)
+    str.Assign(buf, yarn->mYarn_Fill);
+  else
+    str.Truncate();
+}
+
+// WARNING - if yarn is empty, *pResult will not be changed!!!!
+// this is so we can leave default values as they were.
+/* static */ void nsMsgDatabase::YarnToUInt32(struct mdbYarn* yarn,
+                                              uint32_t* pResult) {
+  uint8_t numChars = std::min<mdb_fill>(8, yarn->mYarn_Fill);
+
+  if (numChars == 0) return;
+
+  *pResult = MsgUnhex((char*)yarn->mYarn_Buf, numChars);
+}
+
+// WARNING - if yarn is empty, *pResult will not be changed!!!!
+// this is so we can leave default values as they were.
+/* static */ void nsMsgDatabase::YarnToUInt64(struct mdbYarn* yarn,
+                                              uint64_t* pResult) {
+  uint8_t numChars = std::min<mdb_fill>(16, yarn->mYarn_Fill);
+
+  if (numChars == 0) return;
+
+  *pResult = MsgUnhex((char*)yarn->mYarn_Buf, numChars);
+}
+
+nsresult nsMsgDatabase::GetProperty(nsIMdbRow* row, const char* propertyName,
+                                    char** result) {
+  nsresult err = NS_OK;
+  mdb_token property_token;
+
+  if (m_mdbStore)
+    err = m_mdbStore->StringToToken(GetEnv(), propertyName, &property_token);
+  else
+    err = NS_ERROR_NULL_POINTER;
+  if (NS_SUCCEEDED(err))
+    err = RowCellColumnToCharPtr(row, property_token, result);
+
+  return err;
+}
+
+nsresult nsMsgDatabase::SetProperty(nsIMdbRow* row, const char* propertyName,
+                                    const char* propertyVal) {
+  nsresult err = NS_OK;
+  mdb_token property_token;
+
+  NS_ENSURE_STATE(m_mdbStore);  // db might have been closed out from under us.
+  if (!row) return NS_ERROR_NULL_POINTER;
+
+  err = m_mdbStore->StringToToken(GetEnv(), propertyName, &property_token);
+  if (NS_SUCCEEDED(err))
+    CharPtrToRowCellColumn(row, property_token, propertyVal);
+  return err;
+}
+
+nsresult nsMsgDatabase::GetPropertyAsNSString(nsIMdbRow* row,
+                                              const char* propertyName,
+                                              nsAString& result) {
+  nsresult err = NS_OK;
+  mdb_token property_token;
+
+  NS_ENSURE_STATE(m_mdbStore);  // db might have been closed out from under us.
+  if (!row) return NS_ERROR_NULL_POINTER;
+
+  err = m_mdbStore->StringToToken(GetEnv(), propertyName, &property_token);
+  if (NS_SUCCEEDED(err))
+    err = RowCellColumnTonsString(row, property_token, result);
+
+  return err;
+}
+
+nsresult nsMsgDatabase::SetPropertyFromNSString(nsIMdbRow* row,
+                                                const char* propertyName,
+                                                const nsAString& propertyVal) {
+  nsresult err = NS_OK;
+  mdb_token property_token;
+
+  NS_ENSURE_STATE(m_mdbStore);  // db might have been closed out from under us.
+  if (!row) return NS_ERROR_NULL_POINTER;
+
+  err = m_mdbStore->StringToToken(GetEnv(), propertyName, &property_token);
+  if (NS_SUCCEEDED(err))
+    return SetNSStringPropertyWithToken(row, property_token, propertyVal);
+
+  return err;
+}
+
+nsresult nsMsgDatabase::GetUint32Property(nsIMdbRow* row,
+                                          const char* propertyName,
+                                          uint32_t* result,
+                                          uint32_t defaultValue) {
+  nsresult err = NS_OK;
+  mdb_token property_token;
+
+  NS_ENSURE_STATE(m_mdbStore);  // db might have been closed out from under us.
+  if (!row) return NS_ERROR_NULL_POINTER;
+
+  err = m_mdbStore->StringToToken(GetEnv(), propertyName, &property_token);
+  if (NS_SUCCEEDED(err))
+    err = RowCellColumnToUInt32(row, property_token, result, defaultValue);
+
+  return err;
+}
+
+nsresult nsMsgDatabase::GetUint64Property(nsIMdbRow* row,
+                                          const char* propertyName,
+                                          uint64_t* result,
+                                          uint64_t defaultValue) {
+  nsresult err = NS_OK;
+  mdb_token property_token;
+
+  NS_ENSURE_STATE(m_mdbStore);  // db might have been closed out from under us.
+  if (!row) return NS_ERROR_NULL_POINTER;
+
+  err = m_mdbStore->StringToToken(GetEnv(), propertyName, &property_token);
+  if (NS_SUCCEEDED(err))
+    err = RowCellColumnToUInt64(row, property_token, result, defaultValue);
+
+  return err;
+}
+
+nsresult nsMsgDatabase::SetUint32Property(nsIMdbRow* row,
+                                          const char* propertyName,
+                                          uint32_t propertyVal) {
+  struct mdbYarn yarn;
+  char int32StrBuf[20];
+  yarn.mYarn_Buf = int32StrBuf;
+  yarn.mYarn_Size = sizeof(int32StrBuf);
+  yarn.mYarn_Fill = sizeof(int32StrBuf);
+
+  NS_ENSURE_STATE(m_mdbStore);  // db might have been closed out from under us.
+  if (!row) return NS_ERROR_NULL_POINTER;
+
+  mdb_token property_token;
+
+  nsresult err =
+      m_mdbStore->StringToToken(GetEnv(), propertyName, &property_token);
+  if (NS_SUCCEEDED(err)) {
+    UInt32ToYarn(&yarn, propertyVal);
+    err = row->AddColumn(GetEnv(), property_token, &yarn);
+  }
+  return err;
+}
+
+nsresult nsMsgDatabase::SetUint64Property(nsIMdbRow* row,
+                                          const char* propertyName,
+                                          uint64_t propertyVal) {
+  struct mdbYarn yarn;
+  char int64StrBuf[100];
+  yarn.mYarn_Buf = int64StrBuf;
+  yarn.mYarn_Size = sizeof(int64StrBuf);
+  yarn.mYarn_Fill = sizeof(int64StrBuf);
+
+  NS_ENSURE_STATE(m_mdbStore);  // db might have been closed out from under us.
+  if (!row) return NS_ERROR_NULL_POINTER;
+
+  mdb_token property_token;
+
+  nsresult err =
+      m_mdbStore->StringToToken(GetEnv(), propertyName, &property_token);
+  if (NS_SUCCEEDED(err)) {
+    UInt64ToYarn(&yarn, propertyVal);
+    err = row->AddColumn(GetEnv(), property_token, &yarn);
+  }
+  return err;
+}
+
+nsresult nsMsgDatabase::GetBooleanProperty(nsIMdbRow* row,
+                                           const char* propertyName,
+                                           bool* result,
+                                           bool defaultValue /* = false */) {
+  uint32_t res;
+  nsresult rv =
+      GetUint32Property(row, propertyName, &res, (uint32_t)defaultValue);
+  *result = !!res;
+  return rv;
+}
+
+nsresult nsMsgDatabase::SetBooleanProperty(nsIMdbRow* row,
+                                           const char* propertyName,
+                                           bool propertyVal) {
+  return SetUint32Property(row, propertyName, (uint32_t)propertyVal);
+}
+
+nsresult nsMsgDatabase::SetNSStringPropertyWithToken(
+    nsIMdbRow* row, mdb_token aProperty, const nsAString& propertyStr) {
+  NS_ENSURE_ARG(row);
+  struct mdbYarn yarn;
+
+  yarn.mYarn_Grow = NULL;
+  nsresult err =
+      row->AddColumn(GetEnv(), aProperty, nsStringToYarn(&yarn, propertyStr));
+  free((char*)yarn.mYarn_Buf);  // won't need this when we have nsCString
+  return err;
+}
+
+uint32_t nsMsgDatabase::GetCurVersion() { return kMsgDBVersion; }
+
+NS_IMETHODIMP nsMsgDatabase::SetSummaryValid(bool valid /* = true */) {
+  // If the file was invalid when opened (for example in folder compact), then
+  // it may
+  //  not have been added to the cache. Add it now if missing.
+  if (valid) {
+    nsCOMPtr<nsIMsgDBService> serv(mozilla::components::DB::Service());
+    static_cast<nsMsgDBService*>(serv.get())->EnsureCached(this);
+  }
+  // setting the version to 0 ought to make it pretty invalid.
+  if (m_dbFolderInfo) m_dbFolderInfo->SetVersion(valid ? GetCurVersion() : 0);
+
+  // for default db (and news), there's no nothing to set to make it it valid
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetSummaryValid(bool* aResult) {
+  NS_ENSURE_ARG_POINTER(aResult);
+  *aResult = true;
+  return NS_OK;
+}
+
+// protected routines
+
+// should we thread messages with common subjects that don't start with Re:
+// together? I imagine we might have separate preferences for mail and news, so
+// this is a virtual method.
+bool nsMsgDatabase::ThreadBySubjectWithoutRe() {
+  GetGlobalPrefs();
+  return gThreadWithoutRe;
+}
+
+bool nsMsgDatabase::UseStrictThreading() {
+  GetGlobalPrefs();
+  return gStrictThreading;
+}
+
+// Should we make sure messages are always threaded correctly (see bug 181446)
+bool nsMsgDatabase::UseCorrectThreading() {
+  GetGlobalPrefs();
+  return gCorrectThreading;
+}
+
+// adapted from removed PL_DHashFreeStringKey
+static void msg_DHashFreeStringKey(PLDHashTable* aTable,
+                                   PLDHashEntryHdr* aEntry) {
+  const PLDHashEntryStub* stub = (const PLDHashEntryStub*)aEntry;
+  free((void*)stub->key);
+  PLDHashTable::ClearEntryStub(aTable, aEntry);
+}
+
+PLDHashTableOps nsMsgDatabase::gRefHashTableOps = {
+    PLDHashTable::HashStringKey, PLDHashTable::MatchStringKey,
+    PLDHashTable::MoveEntryStub, msg_DHashFreeStringKey, nullptr};
+
+nsresult nsMsgDatabase::GetRefFromHash(nsCString& reference,
+                                       nsMsgKey* threadId) {
+  // Initialize the reference hash
+  if (!m_msgReferences) {
+    nsresult rv = InitRefHash();
+    if (NS_FAILED(rv)) return rv;
+  }
+
+  // Find reference from the hash
+  PLDHashEntryHdr* entry =
+      m_msgReferences->Search((const void*)reference.get());
+  if (entry) {
+    RefHashElement* element = static_cast<RefHashElement*>(entry);
+    *threadId = element->mThreadId;
+    return NS_OK;
+  }
+
+  return NS_ERROR_FAILURE;
+}
+
+nsresult nsMsgDatabase::AddRefToHash(nsCString& reference, nsMsgKey threadId) {
+  if (m_msgReferences) {
+    PLDHashEntryHdr* entry =
+        m_msgReferences->Add((void*)reference.get(), mozilla::fallible);
+    if (!entry) return NS_ERROR_OUT_OF_MEMORY;  // XXX out of memory
+
+    RefHashElement* element = static_cast<RefHashElement*>(entry);
+    if (!element->mRef) {
+      element->mRef =
+          ToNewCString(reference);  // Will be freed in msg_DHashFreeStringKey()
+      element->mThreadId = threadId;
+      element->mCount = 1;
+    } else
+      element->mCount++;
+  }
+
+  return NS_OK;
+}
+
+nsresult nsMsgDatabase::AddMsgRefsToHash(nsIMsgDBHdr* msgHdr) {
+  uint16_t numReferences = 0;
+  nsMsgKey threadId;
+  nsresult rv = NS_OK;
+
+  msgHdr->GetThreadId(&threadId);
+  msgHdr->GetNumReferences(&numReferences);
+
+  for (int32_t i = 0; i < numReferences; i++) {
+    nsAutoCString reference;
+
+    msgHdr->GetStringReference(i, reference);
+    if (reference.IsEmpty()) break;
+
+    rv = AddRefToHash(reference, threadId);
+    if (NS_FAILED(rv)) break;
+  }
+
+  return rv;
+}
+
+nsresult nsMsgDatabase::RemoveRefFromHash(nsCString& reference) {
+  if (m_msgReferences) {
+    PLDHashEntryHdr* entry =
+        m_msgReferences->Search((const void*)reference.get());
+    if (entry) {
+      RefHashElement* element = static_cast<RefHashElement*>(entry);
+      if (--element->mCount == 0)
+        m_msgReferences->Remove((void*)reference.get());
+    }
+  }
+  return NS_OK;
+}
+
+// Filter only messages with one or more references
+nsresult nsMsgDatabase::RemoveMsgRefsFromHash(nsIMsgDBHdr* msgHdr) {
+  uint16_t numReferences = 0;
+  nsresult rv = NS_OK;
+
+  msgHdr->GetNumReferences(&numReferences);
+
+  for (int32_t i = 0; i < numReferences; i++) {
+    nsAutoCString reference;
+
+    msgHdr->GetStringReference(i, reference);
+    if (reference.IsEmpty()) break;
+
+    rv = RemoveRefFromHash(reference);
+    if (NS_FAILED(rv)) break;
+  }
+
+  return rv;
+}
+
+static nsresult nsReferencesOnlyFilter(nsIMsgDBHdr* msg, void* closure) {
+  uint16_t numReferences = 0;
+  msg->GetNumReferences(&numReferences);
+  return (numReferences) ? NS_OK : NS_ERROR_FAILURE;
+}
+
+nsresult nsMsgDatabase::InitRefHash() {
+  // Delete an existing table just in case
+  if (m_msgReferences) delete m_msgReferences;
+
+  // Create new table
+  m_msgReferences = new PLDHashTable(
+      &gRefHashTableOps, sizeof(struct RefHashElement), MSG_HASH_SIZE);
+  if (!m_msgReferences) return NS_ERROR_OUT_OF_MEMORY;
+
+  // Create enumerator to go through all messages with references
+  nsCOMPtr<nsIMsgEnumerator> enumerator;
+  enumerator = new nsMsgDBEnumerator(this, m_mdbAllMsgHeadersTable,
+                                     nsReferencesOnlyFilter, nullptr);
+  if (enumerator == nullptr) return NS_ERROR_OUT_OF_MEMORY;
+
+  // Populate table with references of existing messages
+  bool hasMore;
+  nsresult rv = NS_OK;
+  while (NS_SUCCEEDED(rv = enumerator->HasMoreElements(&hasMore)) && hasMore) {
+    nsCOMPtr<nsIMsgDBHdr> msgHdr;
+    rv = enumerator->GetNext(getter_AddRefs(msgHdr));
+    if (msgHdr && NS_SUCCEEDED(rv)) rv = AddMsgRefsToHash(msgHdr);
+    if (NS_FAILED(rv)) break;
+  }
+
+  return rv;
+}
+
+nsresult nsMsgDatabase::CreateNewThread(nsMsgKey threadId, const char* subject,
+                                        nsMsgThread** pnewThread) {
+  nsresult err = NS_OK;
+  nsCOMPtr<nsIMdbTable> threadTable;
+  struct mdbOid threadTableOID;
+  struct mdbOid allThreadsTableOID;
+
+  if (!pnewThread || !m_mdbStore) return NS_ERROR_NULL_POINTER;
+
+  threadTableOID.mOid_Scope = m_hdrRowScopeToken;
+  threadTableOID.mOid_Id = threadId;
+
+  // Under some circumstances, mork seems to reuse an old table when we create
+  // one. Prevent problems from that by finding any old table first, and
+  // deleting its rows.
+  nsresult res = GetStore()->GetTable(GetEnv(), &threadTableOID,
+                                      getter_AddRefs(threadTable));
+  if (NS_SUCCEEDED(res) && threadTable) threadTable->CutAllRows(GetEnv());
+
+  err = GetStore()->NewTableWithOid(GetEnv(), &threadTableOID,
+                                    m_threadTableKindToken, false, nullptr,
+                                    getter_AddRefs(threadTable));
+  if (NS_FAILED(err)) return err;
+
+  allThreadsTableOID.mOid_Scope = m_threadRowScopeToken;
+  allThreadsTableOID.mOid_Id = threadId;
+
+  // add a row for this thread in the table of all threads that we'll use
+  // to do our mapping between subject strings and threads.
+  nsCOMPtr<nsIMdbRow> threadRow;
+
+  err = m_mdbStore->GetRow(GetEnv(), &allThreadsTableOID,
+                           getter_AddRefs(threadRow));
+  if (!threadRow) {
+    err = m_mdbStore->NewRowWithOid(GetEnv(), &allThreadsTableOID,
+                                    getter_AddRefs(threadRow));
+    if (NS_SUCCEEDED(err) && threadRow) {
+      if (m_mdbAllThreadsTable)
+        m_mdbAllThreadsTable->AddRow(GetEnv(), threadRow);
+      err = CharPtrToRowCellColumn(threadRow, m_threadSubjectColumnToken,
+                                   subject);
+    }
+  } else {
+#ifdef DEBUG_David_Bienvenu
+    NS_WARNING("odd that thread row already exists");
+#endif
+    threadRow->CutAllColumns(GetEnv());
+    nsCOMPtr<nsIMdbRow> metaRow;
+    threadTable->GetMetaRow(GetEnv(), nullptr, nullptr,
+                            getter_AddRefs(metaRow));
+    if (metaRow) metaRow->CutAllColumns(GetEnv());
+
+    CharPtrToRowCellColumn(threadRow, m_threadSubjectColumnToken, subject);
+  }
+
+  *pnewThread = new nsMsgThread(this, threadTable);
+  if (*pnewThread) {
+    (*pnewThread)->SetThreadKey(threadId);
+    m_cachedThread = *pnewThread;
+    m_cachedThreadId = threadId;
+  }
+  return err;
+}
+
+nsIMsgThread* nsMsgDatabase::GetThreadForReference(nsCString& msgID,
+                                                   nsIMsgDBHdr** pMsgHdr) {
+  nsMsgKey threadId;
+  nsIMsgDBHdr* msgHdr = nullptr;
+  GetMsgHdrForMessageID(msgID.get(), &msgHdr);
+  nsIMsgThread* thread = NULL;
+
+  if (msgHdr != NULL) {
+    if (NS_SUCCEEDED(msgHdr->GetThreadId(&threadId))) {
+      // find thread header for header whose message id we matched.
+      thread = GetThreadForThreadId(threadId);
+    }
+    if (pMsgHdr)
+      *pMsgHdr = msgHdr;
+    else
+      msgHdr->Release();
+  }
+  // Referenced message not found, check if there are messages that reference
+  // same message
+  else if (UseCorrectThreading()) {
+    if (NS_SUCCEEDED(GetRefFromHash(msgID, &threadId)))
+      thread = GetThreadForThreadId(threadId);
+  }
+
+  return thread;
+}
+
+nsIMsgThread* nsMsgDatabase::GetThreadForSubject(nsCString& subject) {
+  nsIMsgThread* thread = nullptr;
+
+  mdbYarn subjectYarn;
+
+  subjectYarn.mYarn_Buf = (void*)subject.get();
+  subjectYarn.mYarn_Fill = PL_strlen(subject.get());
+  subjectYarn.mYarn_Form = 0;
+  subjectYarn.mYarn_Size = subjectYarn.mYarn_Fill;
+
+  nsCOMPtr<nsIMdbRow> threadRow;
+  mdbOid outRowId;
+  if (m_mdbStore) {
+    nsresult result = m_mdbStore->FindRow(
+        GetEnv(), m_threadRowScopeToken, m_threadSubjectColumnToken,
+        &subjectYarn, &outRowId, getter_AddRefs(threadRow));
+    if (NS_SUCCEEDED(result) && threadRow) {
+      // Get key from row
+      mdbOid outOid;
+      nsMsgKey key = nsMsgKey_None;
+      if (NS_SUCCEEDED(threadRow->GetOid(GetEnv(), &outOid)))
+        key = outOid.mOid_Id;
+      // find thread header for header whose message id we matched.
+      // It is fine if key was not found,
+      // GetThreadForThreadId(nsMsgKey_None) returns nullptr.
+      thread = GetThreadForThreadId(key);
+    }
+#ifdef DEBUG_bienvenu1
+    else {
+      nsresult rv;
+      RefPtr<nsMsgThread> pThread;
+
+      nsCOMPtr<nsIMdbPortTableCursor> tableCursor;
+      m_mdbStore->GetPortTableCursor(GetEnv(), m_hdrRowScopeToken,
+                                     m_threadTableKindToken,
+                                     getter_AddRefs(tableCursor));
+
+      nsCOMPtr<nsIMdbTable> table;
+
+      while (true) {
+        rv = tableCursor->NextTable(GetEnv(), getter_AddRefs(table));
+        if (!table) break;
+        if (NS_FAILED(rv)) break;
+
+        pThread = new nsMsgThread(this, table);
+        if (pThread) {
+          nsCString curSubject;
+          pThread->GetSubject(curSubject);
+          if (subject.Equals(curSubject)) {
+            NS_ERROR("thread with subject exists, but FindRow didn't find it");
+            break;
+          }
+        } else
+          break;
+      }
+    }
+#endif
+  }
+  return thread;
+}
+
+// Returns thread that contains a message that references the passed message ID
+nsIMsgThread* nsMsgDatabase::GetThreadForMessageId(nsCString& msgId) {
+  nsIMsgThread* thread = NULL;
+  nsMsgKey threadId;
+
+  if (NS_SUCCEEDED(GetRefFromHash(msgId, &threadId)))
+    thread = GetThreadForThreadId(threadId);
+
+  return thread;
+}
+
+nsresult nsMsgDatabase::ThreadNewHdr(nsMsgHdr* newHdr, bool& newThread) {
+  nsresult result = NS_ERROR_UNEXPECTED;
+  nsCOMPtr<nsIMsgThread> thread;
+  nsCOMPtr<nsIMsgDBHdr> replyToHdr;
+  nsMsgKey threadId = nsMsgKey_None, newHdrKey;
+
+  if (!newHdr) return NS_ERROR_NULL_POINTER;
+
+  newHdr->SetThreadParent(
+      nsMsgKey_None);  // if we're undoing, could have a thread parent
+  uint16_t numReferences = 0;
+  uint32_t newHdrFlags = 0;
+
+  // use raw flags instead of GetFlags, because GetFlags will
+  // pay attention to what's in m_newSet, and this new hdr isn't
+  // in m_newSet yet.
+  newHdr->GetRawFlags(&newHdrFlags);
+  newHdr->GetNumReferences(&numReferences);
+  newHdr->GetMessageKey(&newHdrKey);
+
+  // try reference threading first
+  for (int32_t i = numReferences - 1; i >= 0; i--) {
+    nsAutoCString reference;
+
+    newHdr->GetStringReference(i, reference);
+    // first reference we have hdr for is best top-level hdr.
+    // but we have to handle case of promoting new header to top-level
+    // in case the top-level header comes after a reply.
+
+    if (reference.IsEmpty()) break;
+
+    thread = dont_AddRef(
+        GetThreadForReference(reference, getter_AddRefs(replyToHdr)));
+    if (thread) {
+      if (replyToHdr) {
+        nsMsgKey replyToKey;
+        replyToHdr->GetMessageKey(&replyToKey);
+        // message claims to be a reply to itself - ignore that since it leads
+        // to corrupt threading.
+        if (replyToKey == newHdrKey) {
+          // bad references - throw them all away.
+          newHdr->SetMessageId("");
+          thread = nullptr;
+          break;
+        }
+      }
+      thread->GetThreadKey(&threadId);
+      newHdr->SetThreadId(threadId);
+      result = AddToThread(newHdr, thread, replyToHdr, true);
+      break;
+    }
+  }
+  // if user hasn't said "only thread by ref headers", thread by subject
+  if (!thread && !UseStrictThreading()) {
+    // try subject threading if we couldn't find a reference and the subject
+    // starts with Re:
+    nsCString subject;
+    newHdr->GetSubject(subject);
+    if (ThreadBySubjectWithoutRe() ||
+        (newHdrFlags & nsMsgMessageFlags::HasRe)) {
+      nsAutoCString cSubject(subject);
+      thread = dont_AddRef(GetThreadForSubject(cSubject));
+      if (thread) {
+        thread->GetThreadKey(&threadId);
+        newHdr->SetThreadId(threadId);
+        // TRACE("threading based on subject %s\n", (const char *)
+        // msgHdr->m_subject);
+        // if we move this and do subject threading after, ref threading,
+        // don't thread within children, since we know it won't work. But for
+        // now, pass TRUE.
+        result = AddToThread(newHdr, thread, nullptr, true);
+      }
+    }
+  }
+
+  // Check if this is a new parent to an existing message (that has a reference
+  // to this message)
+  if (!thread && UseCorrectThreading()) {
+    nsCString msgId;
+    newHdr->GetMessageId(getter_Copies(msgId));
+
+    thread = dont_AddRef(GetThreadForMessageId(msgId));
+    if (thread) {
+      thread->GetThreadKey(&threadId);
+      newHdr->SetThreadId(threadId);
+      result = AddToThread(newHdr, thread, nullptr, true);
+    }
+  }
+
+  if (!thread) {
+    // Not a parent or child, make it a new thread for now
+    result = AddNewThread(newHdr);
+    newThread = true;
+  } else {
+    newThread = false;
+  }
+  return result;
+}
+
+nsresult nsMsgDatabase::AddToThread(nsMsgHdr* newHdr, nsIMsgThread* thread,
+                                    nsIMsgDBHdr* inReplyTo,
+                                    bool threadInThread) {
+  // don't worry about real threading yet.
+  return thread->AddChild(newHdr, inReplyTo, threadInThread, this);
+}
+
+nsMsgHdr* nsMsgDatabase::GetMsgHdrForReference(nsCString& reference) {
+  NS_ASSERTION(false, "not implemented yet.");
+  return nullptr;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetMsgHdrForMessageID(const char* aMsgID,
+                                                   nsIMsgDBHdr** aHdr) {
+  NS_ENSURE_ARG_POINTER(aHdr);
+  NS_ENSURE_ARG_POINTER(aMsgID);
+  nsIMsgDBHdr* msgHdr = nullptr;
+  nsresult rv = NS_OK;
+  mdbYarn messageIdYarn;
+
+  messageIdYarn.mYarn_Buf = (void*)aMsgID;
+  messageIdYarn.mYarn_Fill = PL_strlen(aMsgID);
+  messageIdYarn.mYarn_Form = 0;
+  messageIdYarn.mYarn_Size = messageIdYarn.mYarn_Fill;
+
+  nsIMdbRow* hdrRow;
+  mdbOid outRowId;
+  nsresult result;
+  if (m_mdbStore)
+    result = m_mdbStore->FindRow(GetEnv(), m_hdrRowScopeToken,
+                                 m_messageIdColumnToken, &messageIdYarn,
+                                 &outRowId, &hdrRow);
+  else
+    return NS_ERROR_FAILURE;
+  if (NS_SUCCEEDED(result) && hdrRow) {
+    // Get key from row
+    mdbOid outOid;
+    nsMsgKey key = nsMsgKey_None;
+    rv = hdrRow->GetOid(GetEnv(), &outOid);
+    if (NS_WARN_IF(NS_FAILED(rv))) return rv;
+    key = outOid.mOid_Id;
+
+    rv = CreateMsgHdr(hdrRow, key, &msgHdr);
+    if (NS_WARN_IF(NS_FAILED(rv))) return rv;
+  }
+  *aHdr = msgHdr;  // already addreffed above.
+  return NS_OK;    // it's not an error not to find a msg hdr.
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetMsgHdrForGMMsgID(const char* aGMMsgId,
+                                                 nsIMsgDBHdr** aHdr) {
+  NS_ENSURE_ARG_POINTER(aGMMsgId);
+  NS_ENSURE_ARG_POINTER(aHdr);
+  nsIMsgDBHdr* msgHdr = nullptr;
+  nsresult rv = NS_OK;
+  mdbYarn gMailMessageIdYarn;
+  gMailMessageIdYarn.mYarn_Buf = (void*)aGMMsgId;
+  gMailMessageIdYarn.mYarn_Fill = strlen(aGMMsgId);
+  gMailMessageIdYarn.mYarn_Form = 0;
+  gMailMessageIdYarn.mYarn_Size = gMailMessageIdYarn.mYarn_Fill;
+
+  nsIMdbRow* hdrRow;
+  mdbOid outRowId;
+  nsresult result;
+  mdb_token property_token;
+  NS_ENSURE_TRUE(m_mdbStore, NS_ERROR_NULL_POINTER);
+  result = m_mdbStore->StringToToken(GetEnv(), "X-GM-MSGID", &property_token);
+  NS_ENSURE_SUCCESS(result, result);
+  result = m_mdbStore->FindRow(GetEnv(), m_hdrRowScopeToken, property_token,
+                               &gMailMessageIdYarn, &outRowId, &hdrRow);
+  if (NS_SUCCEEDED(result) && hdrRow) {
+    // Get key from row
+    mdbOid outOid;
+    rv = hdrRow->GetOid(GetEnv(), &outOid);
+    NS_ENSURE_SUCCESS(rv, rv);
+    nsMsgKey key = outOid.mOid_Id;
+    rv = CreateMsgHdr(hdrRow, key, &msgHdr);
+    if (NS_WARN_IF(NS_FAILED(rv))) return rv;
+  }
+  *aHdr = msgHdr;
+  return NS_OK;  // it's not an error not to find a msg hdr.
+}
+
+nsIMsgDBHdr* nsMsgDatabase::GetMsgHdrForSubject(nsCString& subject) {
+  nsIMsgDBHdr* msgHdr = nullptr;
+  nsresult rv = NS_OK;
+  mdbYarn subjectYarn;
+
+  subjectYarn.mYarn_Buf = (void*)subject.get();
+  subjectYarn.mYarn_Fill = PL_strlen(subject.get());
+  subjectYarn.mYarn_Form = 0;
+  subjectYarn.mYarn_Size = subjectYarn.mYarn_Fill;
+
+  nsIMdbRow* hdrRow;
+  mdbOid outRowId;
+  nsresult result =
+      GetStore()->FindRow(GetEnv(), m_hdrRowScopeToken, m_subjectColumnToken,
+                          &subjectYarn, &outRowId, &hdrRow);
+  if (NS_SUCCEEDED(result) && hdrRow) {
+    // Get key from row
+    mdbOid outOid;
+    nsMsgKey key = nsMsgKey_None;
+    rv = hdrRow->GetOid(GetEnv(), &outOid);
+    if (NS_WARN_IF(NS_FAILED(rv))) return nullptr;
+    key = outOid.mOid_Id;
+
+    rv = CreateMsgHdr(hdrRow, key, &msgHdr);
+    if (NS_WARN_IF(NS_FAILED(rv))) return nullptr;
+  }
+  return msgHdr;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetThreadContainingMsgHdr(nsIMsgDBHdr* msgHdr,
+                                                       nsIMsgThread** result) {
+  NS_ENSURE_ARG_POINTER(msgHdr);
+  NS_ENSURE_ARG_POINTER(result);
+
+  *result = nullptr;
+  nsMsgKey threadId = nsMsgKey_None;
+  (void)msgHdr->GetThreadId(&threadId);
+  if (threadId != nsMsgKey_None) *result = GetThreadForThreadId(threadId);
+
+  // if we can't find the thread, try using the msg key as the thread id,
+  // because the msg hdr might not have the thread id set correctly
+  // Or maybe the message was deleted?
+  if (!*result) {
+    nsMsgKey msgKey;
+    msgHdr->GetMessageKey(&msgKey);
+    *result = GetThreadForThreadId(msgKey);
+  }
+  // failure is normal when message was deleted
+  return (*result) ? NS_OK : NS_ERROR_FAILURE;
+}
+
+nsresult nsMsgDatabase::GetThreadForMsgKey(nsMsgKey msgKey,
+                                           nsIMsgThread** aResult) {
+  NS_ENSURE_ARG_POINTER(aResult);
+
+  nsCOMPtr<nsIMsgDBHdr> msg;
+  GetMsgHdrForKey(msgKey, getter_AddRefs(msg));
+  if (!msg) return NS_MSG_MESSAGE_NOT_FOUND;
+
+  return GetThreadContainingMsgHdr(msg, aResult);
+}
+
+// caller needs to unrefer.
+nsIMsgThread* nsMsgDatabase::GetThreadForThreadId(nsMsgKey threadId) {
+  nsIMsgThread* retThread = (threadId == m_cachedThreadId && m_cachedThread)
+                                ? m_cachedThread.get()
+                                : FindExistingThread(threadId);
+  if (retThread) {
+    NS_ADDREF(retThread);
+    return retThread;
+  }
+  if (m_mdbStore) {
+    mdbOid tableId;
+    tableId.mOid_Id = threadId;
+    tableId.mOid_Scope = m_hdrRowScopeToken;
+
+    nsCOMPtr<nsIMdbTable> threadTable;
+    nsresult res =
+        m_mdbStore->GetTable(GetEnv(), &tableId, getter_AddRefs(threadTable));
+
+    if (NS_SUCCEEDED(res) && threadTable) {
+      retThread = new nsMsgThread(this, threadTable);
+      if (retThread) {
+        NS_ADDREF(retThread);
+        m_cachedThread = retThread;
+        m_cachedThreadId = threadId;
+      }
+    }
+  }
+  return retThread;
+}
+
+// make the passed in header a thread header
+nsresult nsMsgDatabase::AddNewThread(nsMsgHdr* msgHdr) {
+  if (!msgHdr) return NS_ERROR_NULL_POINTER;
+
+  nsMsgThread* threadHdr = nullptr;
+
+  nsCString subject;
+  nsMsgKey threadKey;
+  msgHdr->GetMessageKey(&threadKey);
+  // can't have a thread with key 1 since that's the table id of the all msg hdr
+  // table, so give it kTableKeyForThreadOne (0xfffffffe).
+  if (threadKey == kAllMsgHdrsTableKey) threadKey = kTableKeyForThreadOne;
+
+  nsresult err = msgHdr->GetSubject(subject);
+
+  err = CreateNewThread(threadKey, subject.get(), &threadHdr);
+  msgHdr->SetThreadId(threadKey);
+  if (threadHdr) {
+    NS_ADDREF(threadHdr);
+    // err = msgHdr->GetSubject(subject);
+    // threadHdr->SetThreadKey(msgHdr->m_messageKey);
+    // threadHdr->SetSubject(subject.get());
+    // need to add the thread table to the db.
+    AddToThread(msgHdr, threadHdr, nullptr, false);
+    NS_RELEASE(threadHdr);
+  }
+  return err;
+}
+
+nsresult nsMsgDatabase::GetBoolPref(const char* prefName, bool* result) {
+  bool prefValue = false;
+  nsresult rv;
+  nsCOMPtr<nsIPrefBranch> pPrefBranch(
+      do_GetService(NS_PREFSERVICE_CONTRACTID, &rv));
+  if (pPrefBranch) {
+    rv = pPrefBranch->GetBoolPref(prefName, &prefValue);
+    *result = prefValue;
+  }
+  return rv;
+}
+
+nsresult nsMsgDatabase::GetIntPref(const char* prefName, int32_t* result) {
+  int32_t prefValue = 0;
+  nsresult rv;
+  nsCOMPtr<nsIPrefBranch> pPrefBranch(
+      do_GetService(NS_PREFSERVICE_CONTRACTID, &rv));
+  if (pPrefBranch) {
+    rv = pPrefBranch->GetIntPref(prefName, &prefValue);
+    *result = prefValue;
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgDatabase::SetAttributeOnPendingHdr(nsIMsgDBHdr* pendingHdr,
+                                                      const char* property,
+                                                      const char* propertyVal) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP nsMsgDatabase::SetUint32AttributeOnPendingHdr(
+    nsIMsgDBHdr* pendingHdr, const char* property, uint32_t propertyVal) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::SetUint64AttributeOnPendingHdr(nsIMsgDBHdr* aPendingHdr,
+                                              const char* aProperty,
+                                              uint64_t aPropertyVal) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::UpdatePendingAttributes(nsIMsgDBHdr* aNewHdr) { return NS_OK; }
+
+NS_IMETHODIMP nsMsgDatabase::GetOfflineOpForKey(
+    nsMsgKey msgKey, bool create, nsIMsgOfflineImapOperation** offlineOp) {
+  NS_ASSERTION(false, "overridden by nsMailDatabase");
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP nsMsgDatabase::RemoveOfflineOp(nsIMsgOfflineImapOperation* op) {
+  NS_ASSERTION(false, "overridden by nsMailDatabase");
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP nsMsgDatabase::ListAllOfflineMsgs(nsTArray<nsMsgKey>& keys) {
+  keys.Clear();
+  nsCOMPtr<nsIMsgEnumerator> enumerator;
+  uint32_t flag = nsMsgMessageFlags::Offline;
+  // if we change this routine to return an enumerator that generates the keys
+  // one by one, we'll need to somehow make a copy of flag for the enumerator
+  // to own, since the enumerator will persist past the life of flag on the
+  // stack.
+  nsresult rv = EnumerateMessagesWithFlag(getter_AddRefs(enumerator), &flag);
+  if (NS_SUCCEEDED(rv) && enumerator) {
+    bool hasMoreElements;
+    while (NS_SUCCEEDED(enumerator->HasMoreElements(&hasMoreElements)) &&
+           hasMoreElements) {
+      // clear out db hdr, because it won't be valid when we get rid of the .msf
+      // file
+      nsCOMPtr<nsIMsgDBHdr> dbMessage;
+      rv = enumerator->GetNext(getter_AddRefs(dbMessage));
+      if (NS_SUCCEEDED(rv) && dbMessage) {
+        nsMsgKey msgKey;
+        dbMessage->GetMessageKey(&msgKey);
+        keys.AppendElement(msgKey);
+      }
+    }
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgDatabase::ListAllOfflineOpIds(
+    nsTArray<nsMsgKey>& offlineOpIds) {
+  NS_ASSERTION(false, "overridden by nsMailDatabase");
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP nsMsgDatabase::ListAllOfflineDeletes(
+    nsTArray<nsMsgKey>& offlineDeletes) {
+  // technically, notimplemented, but no one's putting offline ops in anyway.
+  return NS_OK;
+}
+NS_IMETHODIMP nsMsgDatabase::GetHighWaterArticleNum(nsMsgKey* key) {
+  if (!m_dbFolderInfo) return NS_ERROR_NULL_POINTER;
+  return m_dbFolderInfo->GetHighWater(key);
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetLowWaterArticleNum(nsMsgKey* key) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+/* attribute nsMsgKey NextPseudoMsgKey */
+
+NS_IMETHODIMP nsMsgDatabase::GetNextPseudoMsgKey(nsMsgKey* nextPseudoMsgKey) {
+  NS_ENSURE_ARG_POINTER(nextPseudoMsgKey);
+  *nextPseudoMsgKey = m_nextPseudoMsgKey--;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::SetNextPseudoMsgKey(nsMsgKey nextPseudoMsgKey) {
+  m_nextPseudoMsgKey = nextPseudoMsgKey;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetNextFakeOfflineMsgKey(
+    nsMsgKey* nextFakeOfflineMsgKey) {
+  NS_ENSURE_ARG_POINTER(nextFakeOfflineMsgKey);
+  // iterate over hdrs looking for first non-existent fake offline msg key
+  nsMsgKey fakeMsgKey = kIdStartOfFake;
+
+  bool containsKey;
+  do {
+    ContainsKey(fakeMsgKey, &containsKey);
+    if (!containsKey) break;
+    fakeMsgKey--;
+  } while (containsKey);
+
+  *nextFakeOfflineMsgKey = fakeMsgKey;
+  return NS_OK;
+}
+
+#ifdef DEBUG
+nsresult nsMsgDatabase::DumpContents() {
+  nsTArray<nsMsgKey> keys;
+  nsresult rv = ListAllKeys(keys);
+  NS_ENSURE_SUCCESS(rv, rv);
+  for (nsMsgKey key : keys) {
+    nsCOMPtr<nsIMsgDBHdr> msgHdr;
+    GetMsgHdrForKey(key, getter_AddRefs(msgHdr));
+    if (msgHdr) {
+      nsCString author;
+      nsCString subject;
+
+      msgHdr->GetMessageKey(&key);
+      msgHdr->GetAuthor(getter_Copies(author));
+      msgHdr->GetSubject(subject);
+      printf("hdr key = %u, author = %s subject = %s\n", key, author.get(),
+             subject.get());
+    }
+  }
+
+  nsCOMPtr<nsIMsgThreadEnumerator> threads;
+  rv = EnumerateThreads(getter_AddRefs(threads));
+  NS_ENSURE_SUCCESS(rv, rv);
+  bool hasMore = false;
+  while (NS_SUCCEEDED(rv = threads->HasMoreElements(&hasMore)) && hasMore) {
+    nsCOMPtr<nsIMsgThread> thread;
+    rv = threads->GetNext(getter_AddRefs(thread));
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    nsMsgKey key;
+    thread->GetThreadKey(&key);
+    printf("thread key = %u\n", key);
+    // DumpThread(key);
+  }
+  return NS_OK;
+}
+#endif /* DEBUG */
+
+NS_IMETHODIMP nsMsgDatabase::SetMsgRetentionSettings(
+    nsIMsgRetentionSettings* retentionSettings) {
+  m_retentionSettings = retentionSettings;
+  if (retentionSettings && m_dbFolderInfo) {
+    nsresult rv;
+
+    nsMsgRetainByPreference retainByPreference;
+    uint32_t daysToKeepHdrs;
+    uint32_t numHeadersToKeep;
+    uint32_t daysToKeepBodies;
+    bool cleanupBodiesByDays;
+    bool useServerDefaults;
+    bool applyToFlaggedMessages;
+
+    rv = retentionSettings->GetRetainByPreference(&retainByPreference);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = retentionSettings->GetDaysToKeepHdrs(&daysToKeepHdrs);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = retentionSettings->GetNumHeadersToKeep(&numHeadersToKeep);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = retentionSettings->GetDaysToKeepBodies(&daysToKeepBodies);
+    NS_ENSURE_SUCCESS(rv, rv);
+    (void)retentionSettings->GetCleanupBodiesByDays(&cleanupBodiesByDays);
+    (void)retentionSettings->GetUseServerDefaults(&useServerDefaults);
+    rv = retentionSettings->GetApplyToFlaggedMessages(&applyToFlaggedMessages);
+    NS_ENSURE_SUCCESS(rv, rv);
+    // need to write this to the db. We'll just use the dbfolderinfo to write
+    // properties.
+    m_dbFolderInfo->SetUint32Property("retainBy", retainByPreference);
+    m_dbFolderInfo->SetUint32Property("daysToKeepHdrs", daysToKeepHdrs);
+    m_dbFolderInfo->SetUint32Property("numHdrsToKeep", numHeadersToKeep);
+    m_dbFolderInfo->SetUint32Property("daysToKeepBodies", daysToKeepBodies);
+    m_dbFolderInfo->SetBooleanProperty("cleanupBodies", cleanupBodiesByDays);
+    m_dbFolderInfo->SetBooleanProperty("useServerDefaults", useServerDefaults);
+    m_dbFolderInfo->SetBooleanProperty("applyToFlaggedMessages",
+                                       applyToFlaggedMessages);
+  }
+  Commit(nsMsgDBCommitType::kLargeCommit);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetMsgRetentionSettings(
+    nsIMsgRetentionSettings** retentionSettings) {
+  NS_ENSURE_ARG_POINTER(retentionSettings);
+  if (!m_retentionSettings) {
+    // create a new one, and initialize it from the db.
+    m_retentionSettings = new nsMsgRetentionSettings;
+    if (m_retentionSettings && m_dbFolderInfo) {
+      nsMsgRetainByPreference retainByPreference;
+      uint32_t daysToKeepHdrs = 0;
+      uint32_t numHeadersToKeep = 0;
+      bool useServerDefaults;
+      uint32_t daysToKeepBodies = 0;
+      bool cleanupBodiesByDays = false;
+      bool applyToFlaggedMessages;
+
+      m_dbFolderInfo->GetUint32Property("retainBy",
+                                        nsIMsgRetentionSettings::nsMsgRetainAll,
+                                        &retainByPreference);
+      m_dbFolderInfo->GetUint32Property("daysToKeepHdrs", 0, &daysToKeepHdrs);
+      m_dbFolderInfo->GetUint32Property("numHdrsToKeep", 0, &numHeadersToKeep);
+      m_dbFolderInfo->GetUint32Property("daysToKeepBodies", 0,
+                                        &daysToKeepBodies);
+      m_dbFolderInfo->GetBooleanProperty("useServerDefaults", true,
+                                         &useServerDefaults);
+      m_dbFolderInfo->GetBooleanProperty("cleanupBodies", false,
+                                         &cleanupBodiesByDays);
+      m_dbFolderInfo->GetBooleanProperty("applyToFlaggedMessages", false,
+                                         &applyToFlaggedMessages);
+      m_retentionSettings->SetRetainByPreference(retainByPreference);
+      m_retentionSettings->SetDaysToKeepHdrs(daysToKeepHdrs);
+      m_retentionSettings->SetNumHeadersToKeep(numHeadersToKeep);
+      m_retentionSettings->SetDaysToKeepBodies(daysToKeepBodies);
+      m_retentionSettings->SetUseServerDefaults(useServerDefaults);
+      m_retentionSettings->SetCleanupBodiesByDays(cleanupBodiesByDays);
+      m_retentionSettings->SetApplyToFlaggedMessages(applyToFlaggedMessages);
+    }
+  }
+  NS_IF_ADDREF(*retentionSettings = m_retentionSettings);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::SetMsgDownloadSettings(
+    nsIMsgDownloadSettings* downloadSettings) {
+  m_downloadSettings = downloadSettings;
+  if (downloadSettings && m_dbFolderInfo) {
+    nsresult rv;
+
+    bool useServerDefaults;
+    bool downloadByDate;
+    uint32_t ageLimitOfMsgsToDownload;
+    bool downloadUnreadOnly;
+
+    rv = downloadSettings->GetUseServerDefaults(&useServerDefaults);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = downloadSettings->GetDownloadByDate(&downloadByDate);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = downloadSettings->GetDownloadUnreadOnly(&downloadUnreadOnly);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = downloadSettings->GetAgeLimitOfMsgsToDownload(
+        &ageLimitOfMsgsToDownload);
+    NS_ENSURE_SUCCESS(rv, rv);
+    // need to write this to the db. We'll just use the dbfolderinfo to write
+    // properties.
+    m_dbFolderInfo->SetBooleanProperty("useServerDefaults", useServerDefaults);
+    m_dbFolderInfo->SetBooleanProperty("downloadByDate", downloadByDate);
+    m_dbFolderInfo->SetBooleanProperty("downloadUnreadOnly",
+                                       downloadUnreadOnly);
+    m_dbFolderInfo->SetUint32Property("ageLimit", ageLimitOfMsgsToDownload);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetMsgDownloadSettings(
+    nsIMsgDownloadSettings** downloadSettings) {
+  NS_ENSURE_ARG_POINTER(downloadSettings);
+  if (!m_downloadSettings) {
+    // create a new one, and initialize it from the db.
+    m_downloadSettings = new nsMsgDownloadSettings;
+    if (m_downloadSettings && m_dbFolderInfo) {
+      bool useServerDefaults;
+      bool downloadByDate;
+      uint32_t ageLimitOfMsgsToDownload;
+      bool downloadUnreadOnly;
+
+      m_dbFolderInfo->GetBooleanProperty("useServerDefaults", true,
+                                         &useServerDefaults);
+      m_dbFolderInfo->GetBooleanProperty("downloadByDate", false,
+                                         &downloadByDate);
+      m_dbFolderInfo->GetBooleanProperty("downloadUnreadOnly", false,
+                                         &downloadUnreadOnly);
+      m_dbFolderInfo->GetUint32Property("ageLimit", 0,
+                                        &ageLimitOfMsgsToDownload);
+
+      m_downloadSettings->SetUseServerDefaults(useServerDefaults);
+      m_downloadSettings->SetDownloadByDate(downloadByDate);
+      m_downloadSettings->SetDownloadUnreadOnly(downloadUnreadOnly);
+      m_downloadSettings->SetAgeLimitOfMsgsToDownload(ageLimitOfMsgsToDownload);
+    }
+  }
+  NS_IF_ADDREF(*downloadSettings = m_downloadSettings);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::ApplyRetentionSettings(
+    nsIMsgRetentionSettings* aMsgRetentionSettings, bool aDeleteViaFolder) {
+  NS_ENSURE_ARG_POINTER(aMsgRetentionSettings);
+  nsresult rv = NS_OK;
+
+  if (!m_folder) return NS_ERROR_NULL_POINTER;
+
+  bool isDraftsTemplatesOutbox;
+  uint32_t dtoFlags = nsMsgFolderFlags::Drafts | nsMsgFolderFlags::Templates |
+                      nsMsgFolderFlags::Queue;
+  (void)m_folder->IsSpecialFolder(dtoFlags, true, &isDraftsTemplatesOutbox);
+  // Never apply retention settings to Drafts/Templates/Outbox.
+  if (isDraftsTemplatesOutbox) return NS_OK;
+
+  nsTArray<RefPtr<nsIMsgDBHdr>> msgHdrsToDelete;
+  nsMsgRetainByPreference retainByPreference;
+  aMsgRetentionSettings->GetRetainByPreference(&retainByPreference);
+
+  bool applyToFlaggedMessages = false;
+  aMsgRetentionSettings->GetApplyToFlaggedMessages(&applyToFlaggedMessages);
+
+  uint32_t daysToKeepHdrs = 0;
+  uint32_t numHeadersToKeep = 0;
+  switch (retainByPreference) {
+    case nsIMsgRetentionSettings::nsMsgRetainAll:
+      break;
+    case nsIMsgRetentionSettings::nsMsgRetainByAge:
+      aMsgRetentionSettings->GetDaysToKeepHdrs(&daysToKeepHdrs);
+      rv = FindMessagesOlderThan(daysToKeepHdrs, applyToFlaggedMessages,
+                                 msgHdrsToDelete);
+      break;
+    case nsIMsgRetentionSettings::nsMsgRetainByNumHeaders:
+      aMsgRetentionSettings->GetNumHeadersToKeep(&numHeadersToKeep);
+      rv = FindExcessMessages(numHeadersToKeep, applyToFlaggedMessages,
+                              msgHdrsToDelete);
+      break;
+  }
+  if (m_folder) {
+    // update the time we attempted to purge this folder
+    char dateBuf[100];
+    dateBuf[0] = '\0';
+    PRExplodedTime exploded;
+    PR_ExplodeTime(PR_Now(), PR_LocalTimeParameters, &exploded);
+    PR_FormatTimeUSEnglish(dateBuf, sizeof(dateBuf), "%a %b %d %H:%M:%S %Y",
+                           &exploded);
+    m_folder->SetStringProperty("LastPurgeTime", nsDependentCString(dateBuf));
+  }
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (msgHdrsToDelete.IsEmpty()) {
+    return NS_OK;  // No action required.
+  }
+
+  if (aDeleteViaFolder) {
+    // The folder delete will also delete headers from the DB.
+    rv = m_folder->DeleteMessages(msgHdrsToDelete, nullptr, true, false,
+                                  nullptr, false);
+  } else {
+    // We're just deleting headers in the DB.
+    uint32_t kindex = 0;
+    for (nsIMsgDBHdr* hdr : msgHdrsToDelete) {
+      // Commit after every 300.
+      rv = DeleteHeader(hdr, nullptr, kindex % 300, true);
+      if (NS_FAILED(rv)) {
+        break;
+      }
+    }
+    // compress commit if we deleted more than 10
+    if (msgHdrsToDelete.Length() > 10) {
+      Commit(nsMsgDBCommitType::kCompressCommit);
+    } else {
+      Commit(nsMsgDBCommitType::kLargeCommit);
+    }
+  }
+  return rv;
+}
+
+nsresult nsMsgDatabase::FindMessagesOlderThan(
+    uint32_t daysToKeepHdrs, bool applyToFlaggedMessages,
+    nsTArray<RefPtr<nsIMsgDBHdr>>& hdrsToDelete) {
+  nsresult rv = NS_OK;
+  hdrsToDelete.Clear();
+
+  nsCOMPtr<nsIMsgEnumerator> hdrs;
+  rv = EnumerateMessages(getter_AddRefs(hdrs));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // cutOffDay is the PRTime cut-off point. Any msg with a date less than
+  // that will get purged.
+  PRTime cutOffDay = PR_Now() - daysToKeepHdrs * PR_USEC_PER_DAY;
+
+  bool hasMore = false;
+  while (NS_SUCCEEDED(rv = hdrs->HasMoreElements(&hasMore)) && hasMore) {
+    nsCOMPtr<nsIMsgDBHdr> msg;
+    rv = hdrs->GetNext(getter_AddRefs(msg));
+    NS_ASSERTION(NS_SUCCEEDED(rv), "nsMsgDBEnumerator broken");
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    if (!applyToFlaggedMessages) {
+      uint32_t flags;
+      (void)msg->GetFlags(&flags);
+      if (flags & nsMsgMessageFlags::Marked) {
+        continue;
+      }
+    }
+
+    PRTime date;
+    msg->GetDate(&date);
+    if (date < cutOffDay) {
+      hdrsToDelete.AppendElement(msg);
+    }
+  }
+
+  return NS_OK;
+}
+
+nsresult nsMsgDatabase::FindExcessMessages(
+    uint32_t numHeadersToKeep, bool applyToFlaggedMessages,
+    nsTArray<RefPtr<nsIMsgDBHdr>>& hdrsToDelete) {
+  nsresult rv = NS_OK;
+  hdrsToDelete.Clear();
+
+  nsCOMPtr<nsIMsgEnumerator> hdrs;
+  rv = EnumerateMessages(getter_AddRefs(hdrs));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  mdb_count numHdrs = 0;
+  if (m_mdbAllMsgHeadersTable)
+    m_mdbAllMsgHeadersTable->GetCount(GetEnv(), &numHdrs);
+  else
+    return NS_ERROR_NULL_POINTER;
+
+  bool hasMore = false;
+  while (NS_SUCCEEDED(rv = hdrs->HasMoreElements(&hasMore)) && hasMore) {
+    nsCOMPtr<nsIMsgDBHdr> msg;
+    rv = hdrs->GetNext(getter_AddRefs(msg));
+    NS_ASSERTION(NS_SUCCEEDED(rv), "nsMsgDBEnumerator broken");
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    if (!applyToFlaggedMessages) {
+      uint32_t flags;
+      (void)msg->GetFlags(&flags);
+      if (flags & nsMsgMessageFlags::Marked) {
+        continue;
+      }
+    }
+
+    // this isn't quite right - we want to prefer unread messages (keep all of
+    // those we can)
+    if (numHdrs > numHeadersToKeep) {
+      numHdrs--;
+      hdrsToDelete.AppendElement(msg);
+    }
+  }
+
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(nsMsgRetentionSettings, nsIMsgRetentionSettings)
+
+// Initialise the member variables to reasonable defaults.
+nsMsgRetentionSettings::nsMsgRetentionSettings()
+    : m_retainByPreference(1),
+      m_daysToKeepHdrs(0),
+      m_numHeadersToKeep(0),
+      m_useServerDefaults(true),
+      m_cleanupBodiesByDays(false),
+      m_daysToKeepBodies(0),
+      m_applyToFlaggedMessages(false) {}
+
+nsMsgRetentionSettings::~nsMsgRetentionSettings() {}
+
+/* attribute unsigned long retainByPreference */
+
+NS_IMETHODIMP nsMsgRetentionSettings::GetRetainByPreference(
+    nsMsgRetainByPreference* retainByPreference) {
+  NS_ENSURE_ARG_POINTER(retainByPreference);
+  *retainByPreference = m_retainByPreference;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgRetentionSettings::SetRetainByPreference(
+    nsMsgRetainByPreference retainByPreference) {
+  m_retainByPreference = retainByPreference;
+  return NS_OK;
+}
+
+/* attribute long daysToKeepHdrs; */
+NS_IMETHODIMP nsMsgRetentionSettings::GetDaysToKeepHdrs(
+    uint32_t* aDaysToKeepHdrs) {
+  NS_ENSURE_ARG_POINTER(aDaysToKeepHdrs);
+  *aDaysToKeepHdrs = m_daysToKeepHdrs;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgRetentionSettings::SetDaysToKeepHdrs(
+    uint32_t aDaysToKeepHdrs) {
+  m_daysToKeepHdrs = aDaysToKeepHdrs;
+  return NS_OK;
+}
+
+/* attribute long numHeadersToKeep; */
+NS_IMETHODIMP nsMsgRetentionSettings::GetNumHeadersToKeep(
+    uint32_t* aNumHeadersToKeep) {
+  NS_ENSURE_ARG_POINTER(aNumHeadersToKeep);
+  *aNumHeadersToKeep = m_numHeadersToKeep;
+  return NS_OK;
+}
+NS_IMETHODIMP nsMsgRetentionSettings::SetNumHeadersToKeep(
+    uint32_t aNumHeadersToKeep) {
+  m_numHeadersToKeep = aNumHeadersToKeep;
+  return NS_OK;
+}
+/* attribute boolean useServerDefaults; */
+NS_IMETHODIMP nsMsgRetentionSettings::GetUseServerDefaults(
+    bool* aUseServerDefaults) {
+  NS_ENSURE_ARG_POINTER(aUseServerDefaults);
+  *aUseServerDefaults = m_useServerDefaults;
+  return NS_OK;
+}
+NS_IMETHODIMP nsMsgRetentionSettings::SetUseServerDefaults(
+    bool aUseServerDefaults) {
+  m_useServerDefaults = aUseServerDefaults;
+  return NS_OK;
+}
+
+/* attribute boolean cleanupBodiesByDays; */
+NS_IMETHODIMP nsMsgRetentionSettings::GetCleanupBodiesByDays(
+    bool* aCleanupBodiesByDays) {
+  NS_ENSURE_ARG_POINTER(aCleanupBodiesByDays);
+  *aCleanupBodiesByDays = m_cleanupBodiesByDays;
+  return NS_OK;
+}
+NS_IMETHODIMP nsMsgRetentionSettings::SetCleanupBodiesByDays(
+    bool aCleanupBodiesByDays) {
+  m_cleanupBodiesByDays = aCleanupBodiesByDays;
+  return NS_OK;
+}
+
+/* attribute long daysToKeepBodies; */
+NS_IMETHODIMP nsMsgRetentionSettings::GetDaysToKeepBodies(
+    uint32_t* aDaysToKeepBodies) {
+  NS_ENSURE_ARG_POINTER(aDaysToKeepBodies);
+  *aDaysToKeepBodies = m_daysToKeepBodies;
+  return NS_OK;
+}
+NS_IMETHODIMP nsMsgRetentionSettings::SetDaysToKeepBodies(
+    uint32_t aDaysToKeepBodies) {
+  m_daysToKeepBodies = aDaysToKeepBodies;
+  return NS_OK;
+}
+
+/* attribute boolean applyToFlaggedMessages; */
+NS_IMETHODIMP nsMsgRetentionSettings::GetApplyToFlaggedMessages(
+    bool* aApplyToFlaggedMessages) {
+  NS_ENSURE_ARG_POINTER(aApplyToFlaggedMessages);
+  *aApplyToFlaggedMessages = m_applyToFlaggedMessages;
+  return NS_OK;
+}
+NS_IMETHODIMP nsMsgRetentionSettings::SetApplyToFlaggedMessages(
+    bool aApplyToFlaggedMessages) {
+  m_applyToFlaggedMessages = aApplyToFlaggedMessages;
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(nsMsgDownloadSettings, nsIMsgDownloadSettings)
+
+nsMsgDownloadSettings::nsMsgDownloadSettings() {
+  m_useServerDefaults = false;
+  m_downloadUnreadOnly = false;
+  m_downloadByDate = false;
+  m_ageLimitOfMsgsToDownload = 0;
+}
+
+nsMsgDownloadSettings::~nsMsgDownloadSettings() {}
+
+/* attribute boolean useServerDefaults; */
+NS_IMETHODIMP nsMsgDownloadSettings::GetUseServerDefaults(
+    bool* aUseServerDefaults) {
+  NS_ENSURE_ARG_POINTER(aUseServerDefaults);
+  *aUseServerDefaults = m_useServerDefaults;
+  return NS_OK;
+}
+NS_IMETHODIMP nsMsgDownloadSettings::SetUseServerDefaults(
+    bool aUseServerDefaults) {
+  m_useServerDefaults = aUseServerDefaults;
+  return NS_OK;
+}
+
+/* attribute boolean downloadUnreadOnly; */
+NS_IMETHODIMP nsMsgDownloadSettings::GetDownloadUnreadOnly(
+    bool* aDownloadUnreadOnly) {
+  NS_ENSURE_ARG_POINTER(aDownloadUnreadOnly);
+  *aDownloadUnreadOnly = m_downloadUnreadOnly;
+  return NS_OK;
+}
+NS_IMETHODIMP nsMsgDownloadSettings::SetDownloadUnreadOnly(
+    bool aDownloadUnreadOnly) {
+  m_downloadUnreadOnly = aDownloadUnreadOnly;
+  return NS_OK;
+}
+
+/* attribute boolean downloadByDate; */
+NS_IMETHODIMP nsMsgDownloadSettings::GetDownloadByDate(bool* aDownloadByDate) {
+  NS_ENSURE_ARG_POINTER(aDownloadByDate);
+  *aDownloadByDate = m_downloadByDate;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDownloadSettings::SetDownloadByDate(bool aDownloadByDate) {
+  m_downloadByDate = aDownloadByDate;
+  return NS_OK;
+}
+
+/* attribute long ageLimitOfMsgsToDownload; */
+NS_IMETHODIMP nsMsgDownloadSettings::GetAgeLimitOfMsgsToDownload(
+    uint32_t* ageLimitOfMsgsToDownload) {
+  NS_ENSURE_ARG_POINTER(ageLimitOfMsgsToDownload);
+  *ageLimitOfMsgsToDownload = m_ageLimitOfMsgsToDownload;
+  return NS_OK;
+}
+NS_IMETHODIMP nsMsgDownloadSettings::SetAgeLimitOfMsgsToDownload(
+    uint32_t ageLimitOfMsgsToDownload) {
+  m_ageLimitOfMsgsToDownload = ageLimitOfMsgsToDownload;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetDefaultViewFlags(
+    nsMsgViewFlagsTypeValue* aDefaultViewFlags) {
+  NS_ENSURE_ARG_POINTER(aDefaultViewFlags);
+  GetIntPref("mailnews.default_view_flags", aDefaultViewFlags);
+  if (*aDefaultViewFlags < nsMsgViewFlagsType::kNone ||
+      *aDefaultViewFlags >
+          (nsMsgViewFlagsType::kThreadedDisplay |
+           nsMsgViewFlagsType::kShowIgnored | nsMsgViewFlagsType::kUnreadOnly |
+           nsMsgViewFlagsType::kExpandAll | nsMsgViewFlagsType::kGroupBySort))
+    *aDefaultViewFlags = nsMsgViewFlagsType::kNone;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetDefaultSortType(
+    nsMsgViewSortTypeValue* aDefaultSortType) {
+  NS_ENSURE_ARG_POINTER(aDefaultSortType);
+  GetIntPref("mailnews.default_sort_type", aDefaultSortType);
+  if (*aDefaultSortType < nsMsgViewSortType::byDate ||
+      *aDefaultSortType > nsMsgViewSortType::byAccount)
+    *aDefaultSortType = nsMsgViewSortType::byDate;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetDefaultSortOrder(
+    nsMsgViewSortOrderValue* aDefaultSortOrder) {
+  NS_ENSURE_ARG_POINTER(aDefaultSortOrder);
+  GetIntPref("mailnews.default_sort_order", aDefaultSortOrder);
+  if (*aDefaultSortOrder != nsMsgViewSortOrder::descending)
+    *aDefaultSortOrder = nsMsgViewSortOrder::ascending;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::ResetHdrCacheSize(uint32_t aSize) {
+  if (m_cacheSize > aSize) {
+    m_cacheSize = aSize;
+    ClearHdrCache(false);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::GetNewList(nsTArray<nsMsgKey>& aNewKeys) {
+  aNewKeys = m_newSet.Clone();
+  return NS_OK;
+}
+
+nsresult nsMsgDatabase::GetSearchResultsTable(const nsACString& searchFolderUri,
+                                              bool createIfMissing,
+                                              nsIMdbTable** table) {
+  mdb_kind kindToken;
+  mdb_count numTables;
+  mdb_bool mustBeUnique;
+  NS_ENSURE_TRUE(m_mdbStore, NS_ERROR_NULL_POINTER);
+
+  nsresult err = m_mdbStore->StringToToken(
+      GetEnv(), PromiseFlatCString(searchFolderUri).get(), &kindToken);
+  err = m_mdbStore->GetTableKind(GetEnv(), m_hdrRowScopeToken, kindToken,
+                                 &numTables, &mustBeUnique, table);
+  if ((!*table || NS_FAILED(err)) && createIfMissing)
+    err = m_mdbStore->NewTable(GetEnv(), m_hdrRowScopeToken, kindToken, true,
+                               nullptr, table);
+
+  return *table ? err : NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::GetCachedHits(const nsACString& aSearchFolderUri,
+                             nsIMsgEnumerator** aEnumerator) {
+  nsCOMPtr<nsIMdbTable> table;
+  (void)GetSearchResultsTable(aSearchFolderUri, false, getter_AddRefs(table));
+  if (!table) return NS_ERROR_FAILURE;  // expected result for no cached hits
+  NS_ADDREF(*aEnumerator =
+                new nsMsgDBEnumerator(this, table, nullptr, nullptr));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::RefreshCache(const nsACString& aSearchFolderUri,
+                                          nsTArray<nsMsgKey> const& aNewHits,
+                                          nsTArray<nsMsgKey>& aStaleHits) {
+  nsCOMPtr<nsIMdbTable> table;
+  nsresult err =
+      GetSearchResultsTable(aSearchFolderUri, true, getter_AddRefs(table));
+  NS_ENSURE_SUCCESS(err, err);
+  // update the table so that it just contains aNewHits.
+  // And, keep track of the headers in the original table but not in aNewHits,
+  // so we can put those in aStaleHits. both aNewHits and the db table are
+  // sorted by uid/key. So, start at the beginning of the table and the aNewHits
+  // array.
+  uint32_t newHitIndex = 0;
+  uint32_t tableRowIndex = 0;
+
+  uint32_t rowCount;
+  table->GetCount(GetEnv(), &rowCount);
+  aStaleHits.Clear();
+
+#ifdef DEBUG
+  for (uint64_t i = 1; i < aNewHits.Length(); i++) {
+    NS_ASSERTION(aNewHits[i - 1] < aNewHits[i],
+                 "cached hits for storage not sorted correctly");
+  }
+#endif
+
+  while (newHitIndex < aNewHits.Length() || tableRowIndex < rowCount) {
+    mdbOid oid;
+    nsMsgKey tableRowKey = nsMsgKey_None;
+    if (tableRowIndex < rowCount) {
+      nsresult ret = table->PosToOid(GetEnv(), tableRowIndex, &oid);
+      if (NS_FAILED(ret)) {
+        tableRowIndex++;
+        continue;
+      }
+      tableRowKey =
+          oid.mOid_Id;  // ### TODO need the real key for the 0th key problem.
+    }
+
+    if (newHitIndex < aNewHits.Length() &&
+        aNewHits[newHitIndex] == tableRowKey) {
+      newHitIndex++;
+      tableRowIndex++;
+      continue;
+    } else if (tableRowIndex >= rowCount ||
+               (newHitIndex < aNewHits.Length() &&
+                aNewHits[newHitIndex] < tableRowKey)) {
+      nsCOMPtr<nsIMdbRow> hdrRow;
+      mdbOid rowObjectId;
+
+      rowObjectId.mOid_Id = aNewHits[newHitIndex];
+      rowObjectId.mOid_Scope = m_hdrRowScopeToken;
+      err = m_mdbStore->GetRow(GetEnv(), &rowObjectId, getter_AddRefs(hdrRow));
+      if (hdrRow) {
+        table->AddRow(GetEnv(), hdrRow);
+        mdb_pos newPos;
+        table->MoveRow(GetEnv(), hdrRow, rowCount, tableRowIndex, &newPos);
+        rowCount++;
+        tableRowIndex++;
+      }
+      newHitIndex++;
+      continue;
+    } else if (newHitIndex >= aNewHits.Length() ||
+               aNewHits[newHitIndex] > tableRowKey) {
+      aStaleHits.AppendElement(tableRowKey);
+      table->CutOid(GetEnv(), &oid);
+      rowCount--;
+      continue;  // don't increment tableRowIndex since we removed that row.
+    }
+  }
+
+#ifdef DEBUG_David_Bienvenu
+  printf("after refreshing cache\n");
+  // iterate over table and assert that it's in id order
+  table->GetCount(GetEnv(), &rowCount);
+  mdbOid oid;
+  tableRowIndex = 0;
+  mdb_id prevId = 0;
+  while (tableRowIndex < rowCount) {
+    nsresult ret = table->PosToOid(m_mdbEnv, tableRowIndex++, &oid);
+    if (tableRowIndex > 1 && oid.mOid_Id <= prevId) {
+      NS_ASSERTION(
+          false, "inserting row into cached hits table, not sorted correctly");
+      printf("key %lx is before or equal %lx\n", prevId, oid.mOid_Id);
+    }
+    prevId = oid.mOid_Id;
+  }
+
+#endif
+  Commit(nsMsgDBCommitType::kLargeCommit);
+  return NS_OK;
+}
+
+// search sorted table
+mdb_pos nsMsgDatabase::FindInsertIndexInSortedTable(nsIMdbTable* table,
+                                                    mdb_id idToInsert) {
+  mdb_pos searchPos = 0;
+  uint32_t rowCount;
+  table->GetCount(GetEnv(), &rowCount);
+  mdb_pos hi = rowCount;
+  mdb_pos lo = 0;
+
+  while (hi > lo) {
+    mdbOid outOid;
+    searchPos = (lo + hi - 1) / 2;
+    table->PosToOid(GetEnv(), searchPos, &outOid);
+    if (outOid.mOid_Id == idToInsert) {
+      NS_ASSERTION(false, "id shouldn't be in table");
+      return hi;
+    }
+    if (outOid.mOid_Id > idToInsert)
+      hi = searchPos;
+    else  // if (outOid.mOid_Id <  idToInsert)
+      lo = searchPos + 1;
+  }
+  return hi;
+}
+NS_IMETHODIMP
+nsMsgDatabase::UpdateHdrInCache(const nsACString& aSearchFolderUri,
+                                nsIMsgDBHdr* aHdr, bool aAdd) {
+  nsCOMPtr<nsIMdbTable> table;
+  nsresult err =
+      GetSearchResultsTable(aSearchFolderUri, true, getter_AddRefs(table));
+  NS_ENSURE_SUCCESS(err, err);
+  nsMsgKey key;
+  err = aHdr->GetMessageKey(&key);
+  nsMsgHdr* msgHdr =
+      static_cast<nsMsgHdr*>(aHdr);  // closed system, so this is ok
+  nsIMdbRow* hdrRow = msgHdr->GetMDBRow();
+  if (NS_SUCCEEDED(err) && m_mdbStore && hdrRow) {
+    if (!aAdd) {
+      table->CutRow(m_mdbEnv, hdrRow);
+    } else {
+      mdbOid rowId;
+      hdrRow->GetOid(m_mdbEnv, &rowId);
+      mdb_pos insertPos = FindInsertIndexInSortedTable(table, rowId.mOid_Id);
+      uint32_t rowCount;
+      table->GetCount(m_mdbEnv, &rowCount);
+      table->AddRow(m_mdbEnv, hdrRow);
+      mdb_pos newPos;
+      table->MoveRow(m_mdbEnv, hdrRow, rowCount, insertPos, &newPos);
+    }
+  }
+
+  //  if (aAdd)
+  // if we need to add this hdr, we need to insert it in key order.
+  return NS_OK;
+}
+NS_IMETHODIMP
+nsMsgDatabase::HdrIsInCache(const nsACString& aSearchFolderUri,
+                            nsIMsgDBHdr* aHdr, bool* aResult) {
+  NS_ENSURE_ARG_POINTER(aResult);
+  nsCOMPtr<nsIMdbTable> table;
+  nsresult err =
+      GetSearchResultsTable(aSearchFolderUri, true, getter_AddRefs(table));
+  NS_ENSURE_SUCCESS(err, err);
+  nsMsgKey key;
+  aHdr->GetMessageKey(&key);
+  mdbOid rowObjectId;
+  rowObjectId.mOid_Id = key;
+  rowObjectId.mOid_Scope = m_hdrRowScopeToken;
+  mdb_bool hasOid;
+  err = table->HasOid(GetEnv(), &rowObjectId, &hasOid);
+  *aResult = hasOid;
+  return err;
+}
diff --git a/comm/mailnews/db/msgdb/src/nsMsgDatabaseEnumerators.cpp b/comm/mailnews/db/msgdb/src/nsMsgDatabaseEnumerators.cpp
new file mode 100644
index 0000000000..a64ef46f57
--- /dev/null
+++ b/comm/mailnews/db/msgdb/src/nsMsgDatabaseEnumerators.cpp
@@ -0,0 +1,317 @@
+/* -*- 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 "nsMsgDatabaseEnumerators.h"
+#include "nsMsgDatabase.h"
+#include "nsIMsgHdr.h"
+#include "nsMsgThread.h"
+
+/*
+ * nsMsgDBEnumerator implementation
+ */
+
+nsMsgDBEnumerator::nsMsgDBEnumerator(nsMsgDatabase* db, nsIMdbTable* table,
+                                     nsMsgDBEnumeratorFilter filter,
+                                     void* closure, bool iterateForwards)
+    : mDB(db),
+      mDone(false),
+      mIterateForwards(iterateForwards),
+      mFilter(filter),
+      mClosure(closure) {
+  mTable = table;
+  mRowPos = 0;
+  mDB->m_msgEnumerators.AppendElement(this);
+}
+
+nsMsgDBEnumerator::~nsMsgDBEnumerator() { Invalidate(); }
+
+void nsMsgDBEnumerator::Invalidate() {
+  // Order is important here. If the database is destroyed first, releasing
+  // the cursor will crash (due, I think, to a disconnect between XPCOM and
+  // Mork internal memory management).
+  mRowCursor = nullptr;
+  mTable = nullptr;
+  mResultHdr = nullptr;
+  mDone = true;
+  if (mDB) {
+    mDB->m_msgEnumerators.RemoveElement(this);
+    mDB = nullptr;
+  }
+}
+
+nsresult nsMsgDBEnumerator::GetRowCursor() {
+  mDone = false;
+
+  if (!mDB || !mTable) return NS_ERROR_NULL_POINTER;
+
+  if (mIterateForwards) {
+    mRowPos = -1;
+  } else {
+    mdb_count numRows;
+    mTable->GetCount(mDB->GetEnv(), &numRows);
+    mRowPos = numRows;  // startPos is 0 relative.
+  }
+  return mTable->GetTableRowCursor(mDB->GetEnv(), mRowPos,
+                                   getter_AddRefs(mRowCursor));
+}
+
+NS_IMETHODIMP nsMsgDBEnumerator::GetNext(nsIMsgDBHdr** aItem) {
+  if (!aItem) return NS_ERROR_NULL_POINTER;
+  *aItem = nullptr;
+
+  // If we've already got one ready, return it.
+  if (mResultHdr) {
+    mResultHdr.forget(aItem);
+    return NS_OK;
+  }
+
+  // Bail out if enumerator has been invalidated.
+  if (!mDB) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsresult rv = InternalGetNext(aItem);
+  NS_ENSURE_SUCCESS(rv, rv);
+  return *aItem ? NS_OK : NS_ERROR_FAILURE;
+}
+
+nsresult nsMsgDBEnumerator::InternalGetNext(nsIMsgDBHdr** nextHdr) {
+  nsresult rv;
+
+  *nextHdr = nullptr;
+
+  if (!mRowCursor) {
+    rv = GetRowCursor();
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  while (true) {
+    nsIMdbRow* hdrRow;
+    if (mIterateForwards) {
+      rv = mRowCursor->NextRow(mDB->GetEnv(), &hdrRow, &mRowPos);
+    } else {
+      rv = mRowCursor->PrevRow(mDB->GetEnv(), &hdrRow, &mRowPos);
+    }
+    NS_ENSURE_SUCCESS(rv, rv);
+    if (!hdrRow) {
+      // No more rows, so we're done.
+      *nextHdr = nullptr;
+      return NS_OK;
+    }
+
+    // Get key from row
+    mdbOid outOid;
+    nsMsgKey key = nsMsgKey_None;
+    rv = hdrRow->GetOid(mDB->GetEnv(), &outOid);
+    NS_ENSURE_SUCCESS(rv, rv);
+    key = outOid.mOid_Id;
+
+    nsCOMPtr<nsIMsgDBHdr> hdr;
+    rv = mDB->CreateMsgHdr(hdrRow, key, getter_AddRefs(hdr));
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // Ignore expunged messages.
+    uint32_t flags;
+    hdr->GetFlags(&flags);
+    if (flags & nsMsgMessageFlags::Expunged) {
+      continue;
+    }
+
+    // Ignore anything which doesn't pass the filter func (if there is one).
+    if (mFilter && NS_FAILED(mFilter(hdr, mClosure))) {
+      continue;
+    }
+
+    // If we get this far, we've found it.
+    hdr.forget(nextHdr);
+    return NS_OK;
+  }
+}
+
+NS_IMETHODIMP nsMsgDBEnumerator::HasMoreElements(bool* aResult) {
+  if (!aResult) return NS_ERROR_NULL_POINTER;
+
+  if (!mResultHdr) {
+    // Bail out if enumerator has been invalidated.
+    if (!mDB) {
+      return NS_ERROR_FAILURE;
+    }
+
+    nsresult rv = InternalGetNext(getter_AddRefs(mResultHdr));
+    NS_ENSURE_SUCCESS(rv, rv);
+    if (!mResultHdr) {
+      mDone = true;
+    }
+  }
+
+  *aResult = !mDone;
+  return NS_OK;
+}
+
+/*
+ * nsMsgFilteredDBEnumerator implementation
+ */
+
+nsMsgFilteredDBEnumerator::nsMsgFilteredDBEnumerator(nsMsgDatabase* db,
+                                                     nsIMdbTable* table,
+                                                     bool reverse)
+    : nsMsgDBEnumerator(db, table, nullptr, nullptr, !reverse) {}
+
+nsMsgFilteredDBEnumerator::~nsMsgFilteredDBEnumerator() {}
+
+/**
+ * Create the search session for the enumerator,
+ * add the scope term for "folder" to the search session, and add the search
+ * terms in the array to the search session.
+ */
+nsresult nsMsgFilteredDBEnumerator::InitSearchSession(
+    const nsTArray<RefPtr<nsIMsgSearchTerm>>& searchTerms,
+    nsIMsgFolder* folder) {
+  nsresult rv;
+  m_searchSession =
+      do_CreateInstance("@mozilla.org/messenger/searchSession;1", &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  m_searchSession->AddScopeTerm(nsMsgSearchScope::offlineMail, folder);
+  for (auto searchTerm : searchTerms) {
+    m_searchSession->AppendTerm(searchTerm);
+  }
+  return NS_OK;
+}
+
+nsresult nsMsgFilteredDBEnumerator::InternalGetNext(nsIMsgDBHdr** nextHdr) {
+  nsCOMPtr<nsIMsgDBHdr> hdr;
+  while (true) {
+    nsresult rv = nsMsgDBEnumerator::InternalGetNext(getter_AddRefs(hdr));
+    NS_ENSURE_SUCCESS(rv, rv);
+    if (!hdr) {
+      break;  // No more.
+    }
+    bool matches;
+    rv = m_searchSession->MatchHdr(hdr, mDB, &matches);
+    NS_ENSURE_SUCCESS(rv, rv);
+    if (matches) {
+      break;  // Found one!
+    }
+  }
+  hdr.forget(nextHdr);
+  return NS_OK;
+}
+
+/*
+ * nsMsgDBThreadEnumerator implementation
+ */
+
+nsMsgDBThreadEnumerator::nsMsgDBThreadEnumerator(
+    nsMsgDatabase* db, nsMsgDBThreadEnumeratorFilter filter)
+    : mDB(db),
+      mTableCursor(nullptr),
+      mResultThread(nullptr),
+      mDone(false),
+      mFilter(filter) {
+  mDB->m_threadEnumerators.AppendElement(this);
+  mNextPrefetched = false;
+}
+
+nsMsgDBThreadEnumerator::~nsMsgDBThreadEnumerator() { Invalidate(); }
+
+void nsMsgDBThreadEnumerator::Invalidate() {
+  // Order is important here. If the database is destroyed first, releasing
+  // the cursor will crash (due, I think, to a disconnect between XPCOM and
+  // Mork internal memory management).
+  mTableCursor = nullptr;
+  mResultThread = nullptr;
+  mDone = true;
+  if (mDB) {
+    mDB->m_threadEnumerators.RemoveElement(this);
+    mDB = nullptr;
+  }
+}
+
+nsresult nsMsgDBThreadEnumerator::GetTableCursor(void) {
+  nsresult rv = NS_OK;
+
+  // DB might have disappeared.
+  if (!mDB || !mDB->m_mdbStore) return NS_ERROR_NULL_POINTER;
+  if (NS_FAILED(rv)) return rv;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDBThreadEnumerator::HasMoreElements(bool* aResult) {
+  NS_ENSURE_ARG_POINTER(aResult);
+
+  if (!mNextPrefetched) {
+    PrefetchNext();
+  }
+  *aResult = !mDone;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDBThreadEnumerator::GetNext(nsIMsgThread** aItem) {
+  NS_ENSURE_ARG_POINTER(aItem);
+
+  *aItem = nullptr;
+  nsresult rv = NS_OK;
+  if (!mNextPrefetched) rv = PrefetchNext();
+  if (NS_SUCCEEDED(rv)) {
+    if (mResultThread) {
+      NS_ADDREF(*aItem = mResultThread);
+      mNextPrefetched = false;
+    }
+  }
+  return rv;
+}
+
+nsresult nsMsgDBThreadEnumerator::PrefetchNext() {
+  nsresult rv;
+
+  // DB might have disappeared.
+  if (!mDB || !mDB->m_mdbStore) {
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  if (!mTableCursor) {
+    rv = mDB->m_mdbStore->GetPortTableCursor(
+        mDB->GetEnv(), mDB->m_hdrRowScopeToken, mDB->m_threadTableKindToken,
+        getter_AddRefs(mTableCursor));
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  nsCOMPtr<nsIMdbTable> table;
+  while (true) {
+    mResultThread = nullptr;
+    rv = mTableCursor->NextTable(mDB->GetEnv(), getter_AddRefs(table));
+    if (!table) {
+      mDone = true;
+      return NS_ERROR_FAILURE;
+    }
+    if (NS_FAILED(rv)) {
+      mDone = true;
+      return rv;
+    }
+
+    mdbOid tableId;
+    table->GetOid(mDB->GetEnv(), &tableId);
+
+    mResultThread = mDB->FindExistingThread(tableId.mOid_Id);
+    if (!mResultThread) mResultThread = new nsMsgThread(mDB, table);
+
+    if (mResultThread) {
+      uint32_t numChildren = 0;
+      mResultThread->GetNumChildren(&numChildren);
+      // we've got empty thread; don't tell caller about it.
+      if (numChildren == 0) continue;
+    }
+    if (mFilter && NS_FAILED(mFilter(mResultThread)))
+      continue;
+    else
+      break;
+  }
+  if (mResultThread) {
+    mNextPrefetched = true;
+    return NS_OK;
+  }
+  return NS_ERROR_FAILURE;
+}
diff --git a/comm/mailnews/db/msgdb/src/nsMsgDatabaseEnumerators.h b/comm/mailnews/db/msgdb/src/nsMsgDatabaseEnumerators.h
new file mode 100644
index 0000000000..f68b084611
--- /dev/null
+++ b/comm/mailnews/db/msgdb/src/nsMsgDatabaseEnumerators.h
@@ -0,0 +1,133 @@
+/* -*- 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 _nsMsgDatabaseEnumerators_H_
+#define _nsMsgDatabaseEnumerators_H_
+
+/*
+ * This file provides some enumerator classes, private to nsMsgDatabase.
+ * The outside world would only ever see these as nsIMsgEnumerator or
+ * nsIMsgThreadEnumerator.
+ *
+ * These enumerators automatically register themselves with the nsMsgDatabase
+ * during construction/destruction. This lets the database track all
+ * outstanding enumerators, so they can be invalidated if the database is
+ * destroyed or ForceClosed().
+ * Due to this lifecycle coupling, we try to avoid using refcounted pointers
+ * here, as we don't want outstanding enumerators to lock an otherwise unused
+ * database in existence.
+ */
+
+#include "nsMsgEnumerator.h"
+#include "nsCOMPtr.h"
+#include "nsTArray.h"
+#include "mdb.h"
+#include "nsIDBChangeListener.h"
+
+#include "nsIMsgSearchTerm.h"
+#include "nsIMsgSearchSession.h"
+
+class nsMsgDatabase;
+class nsIMdbTable;
+class nsIMdbTableRowCursor;
+class nsIMsgFolder;
+
+/**
+ * Enumerates over messages, forwards or backward, with an optional filter fn.
+ */
+class nsMsgDBEnumerator : public nsBaseMsgEnumerator {
+ public:
+  // nsIMsgEnumerator support.
+  NS_IMETHOD GetNext(nsIMsgDBHdr** aItem) override;
+  NS_IMETHOD HasMoreElements(bool* aResult) override;
+
+  // Function type for filtering which messages are enumerated.
+  typedef nsresult (*nsMsgDBEnumeratorFilter)(nsIMsgDBHdr* hdr, void* closure);
+
+  nsMsgDBEnumerator(nsMsgDatabase* db, nsIMdbTable* table,
+                    nsMsgDBEnumeratorFilter filter, void* closure,
+                    bool iterateForwards = true);
+  // Called by db when no longer valid (db is being destroyed or ForcedClosed).
+  void Invalidate();
+
+ protected:
+  // internals
+  nsresult GetRowCursor();
+
+  // Returns next message or nullptr if none more.
+  virtual nsresult InternalGetNext(nsIMsgDBHdr** nextHdr);
+
+  // Our source DB. Not refcounted, because we don't want to lock the DB
+  // in existence. The enumerator is registered with the DB, and the DB will
+  // call Invalidate() if it is destroyed or ForceClosed().
+  nsMsgDatabase* mDB;
+  nsCOMPtr<nsIMdbTableRowCursor> mRowCursor;
+  mdb_pos mRowPos;
+  nsCOMPtr<nsIMsgDBHdr> mResultHdr;
+  bool mDone;
+  bool mIterateForwards;
+  nsMsgDBEnumeratorFilter mFilter;
+  nsIMdbTable* mTable;
+  void* mClosure;
+
+  virtual ~nsMsgDBEnumerator() override;
+};
+
+/**
+ * Enumerate over messages which match the given search terms.
+ */
+class nsMsgFilteredDBEnumerator : public nsMsgDBEnumerator {
+ public:
+  nsMsgFilteredDBEnumerator(nsMsgDatabase* db, nsIMdbTable* table,
+                            bool reverse);
+  virtual ~nsMsgFilteredDBEnumerator() override;
+  nsresult InitSearchSession(
+      const nsTArray<RefPtr<nsIMsgSearchTerm>>& searchTerms,
+      nsIMsgFolder* folder);
+
+ protected:
+  virtual nsresult InternalGetNext(nsIMsgDBHdr** nextHdr) override;
+
+  nsCOMPtr<nsIMsgSearchSession> m_searchSession;
+};
+
+/**
+ * Helper class for fetching message threads from a database.
+ * This enumerator automatically registers itself with the nsMsgDatabase.
+ * If the DB is destroyed or ForceClosed() it will call the enumerators
+ * Invalidate() method.
+ */
+class nsMsgDBThreadEnumerator : public nsBaseMsgThreadEnumerator {
+ public:
+  // nsIMsgThreadEnumerator support.
+  NS_IMETHOD GetNext(nsIMsgThread** aItem) override;
+  NS_IMETHOD HasMoreElements(bool* aResult) override;
+
+  // Function type for filtering threads that appear in the enumeration.
+  typedef nsresult (*nsMsgDBThreadEnumeratorFilter)(nsIMsgThread* thread);
+
+  nsMsgDBThreadEnumerator(nsMsgDatabase* db,
+                          nsMsgDBThreadEnumeratorFilter filter);
+
+  // Called by DB when being destroyed or ForcedClosed.
+  void Invalidate();
+
+ protected:
+  virtual ~nsMsgDBThreadEnumerator();
+  nsresult GetTableCursor(void);
+  nsresult PrefetchNext();
+
+  // Our source DB. Not refcounted, because we don't want to lock the DB
+  // in existence. The enumerator is registered with the DB, and the DB will
+  // call Invalidate() if it is destroyed or ForceClosed().
+  nsMsgDatabase* mDB;
+  nsCOMPtr<nsIMdbPortTableCursor> mTableCursor;
+  RefPtr<nsIMsgThread> mResultThread;
+  bool mDone;
+  bool mNextPrefetched;
+  nsMsgDBThreadEnumeratorFilter mFilter;
+};
+
+#endif  // _nsMsgDatabaseEnumerators_H_
diff --git a/comm/mailnews/db/msgdb/src/nsMsgHdr.cpp b/comm/mailnews/db/msgdb/src/nsMsgHdr.cpp
new file mode 100644
index 0000000000..c3d36d9b9b
--- /dev/null
+++ b/comm/mailnews/db/msgdb/src/nsMsgHdr.cpp
@@ -0,0 +1,936 @@
+/* -*- 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 "msgCore.h"
+#include "mozilla/mailnews/MimeHeaderParser.h"
+#include "nsMsgHdr.h"
+#include "nsMsgDatabase.h"
+#include "nsMsgUtils.h"
+#include "nsMsgMessageFlags.h"
+#include "nsIMsgThread.h"
+#include "mozilla/Attributes.h"
+#include "nsStringEnumerator.h"
+#ifdef DEBUG
+#  include "nsPrintfCString.h"
+#endif
+using namespace mozilla::mailnews;
+
+NS_IMPL_ISUPPORTS(nsMsgHdr, nsIMsgDBHdr)
+
+#define FLAGS_INITED 0x1
+#define CACHED_VALUES_INITED 0x2
+#define REFERENCES_INITED 0x4
+#define THREAD_PARENT_INITED 0x8
+
+nsMsgHdr::nsMsgHdr(nsMsgDatabase* db, nsIMdbRow* dbRow) {
+  m_mdb = db;
+  Init();
+  m_mdbRow = dbRow;
+  if (m_mdb) {
+    NS_ADDREF(m_mdb);  // Released in DTOR.
+    mdbOid outOid;
+    if (dbRow && NS_SUCCEEDED(dbRow->GetOid(m_mdb->GetEnv(), &outOid))) {
+      m_messageKey = outOid.mOid_Id;
+      m_mdb->AddHdrToUseCache((nsIMsgDBHdr*)this, m_messageKey);
+    }
+  }
+}
+
+void nsMsgHdr::Init() {
+  m_initedValues = 0;
+  m_messageKey = nsMsgKey_None;
+  m_messageSize = 0;
+  m_date = 0;
+  m_flags = 0;
+  m_mdbRow = NULL;
+  m_threadId = nsMsgKey_None;
+  m_threadParent = nsMsgKey_None;
+}
+
+nsresult nsMsgHdr::InitCachedValues() {
+  nsresult err = NS_OK;
+
+  if (!m_mdb || !m_mdbRow) return NS_ERROR_NULL_POINTER;
+
+  if (!(m_initedValues & CACHED_VALUES_INITED)) {
+    uint32_t uint32Value;
+    mdbOid outOid;
+    if (NS_SUCCEEDED(m_mdbRow->GetOid(m_mdb->GetEnv(), &outOid)))
+      m_messageKey = outOid.mOid_Id;
+
+    err = GetUInt32Column(m_mdb->m_messageSizeColumnToken, &m_messageSize);
+
+    err = GetUInt32Column(m_mdb->m_dateColumnToken, &uint32Value);
+    Seconds2PRTime(uint32Value, &m_date);
+
+    err = GetUInt32Column(m_mdb->m_messageThreadIdColumnToken, &m_threadId);
+
+    if (NS_SUCCEEDED(err)) m_initedValues |= CACHED_VALUES_INITED;
+  }
+  return err;
+}
+
+nsresult nsMsgHdr::InitFlags() {
+  nsresult err = NS_OK;
+
+  if (!m_mdb) return NS_ERROR_NULL_POINTER;
+
+  if (!(m_initedValues & FLAGS_INITED)) {
+    err = GetUInt32Column(m_mdb->m_flagsColumnToken, &m_flags);
+    m_flags &= ~nsMsgMessageFlags::New;  // don't get new flag from MDB
+
+    if (NS_SUCCEEDED(err)) m_initedValues |= FLAGS_INITED;
+  }
+
+  return err;
+}
+
+nsMsgHdr::~nsMsgHdr() {
+  if (m_mdbRow) {
+    if (m_mdb) {
+      NS_RELEASE(m_mdbRow);
+      m_mdb->RemoveHdrFromUseCache((nsIMsgDBHdr*)this, m_messageKey);
+    }
+  }
+  NS_IF_RELEASE(m_mdb);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetMessageKey(nsMsgKey* result) {
+  if (m_messageKey == nsMsgKey_None && m_mdbRow != NULL) {
+    mdbOid outOid;
+    if (NS_SUCCEEDED(m_mdbRow->GetOid(m_mdb->GetEnv(), &outOid)))
+      m_messageKey = outOid.mOid_Id;
+  }
+  *result = m_messageKey;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetThreadId(nsMsgKey* result) {
+  if (!(m_initedValues & CACHED_VALUES_INITED)) InitCachedValues();
+
+  if (result) {
+    *result = m_threadId;
+    return NS_OK;
+  }
+  return NS_ERROR_NULL_POINTER;
+}
+
+NS_IMETHODIMP nsMsgHdr::SetThreadId(nsMsgKey inKey) {
+  m_threadId = inKey;
+  return SetUInt32Column(m_threadId, m_mdb->m_messageThreadIdColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetMessageKey(nsMsgKey value) {
+  m_messageKey = value;
+  return NS_OK;
+}
+
+nsresult nsMsgHdr::GetRawFlags(uint32_t* result) {
+  if (!(m_initedValues & FLAGS_INITED)) InitFlags();
+  *result = m_flags;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetFlags(uint32_t* result) {
+  if (!(m_initedValues & FLAGS_INITED)) InitFlags();
+  if (m_mdb)
+    *result = m_mdb->GetStatusFlags(this, m_flags);
+  else
+    *result = m_flags;
+#ifdef DEBUG_bienvenu
+  NS_ASSERTION(!(*result & (nsMsgMessageFlags::Elided)),
+               "shouldn't be set in db");
+#endif
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::SetFlags(uint32_t flags) {
+#ifdef DEBUG_bienvenu
+  NS_ASSERTION(!(flags & (nsMsgMessageFlags::Elided)),
+               "shouldn't set this flag on db");
+#endif
+  m_initedValues |= FLAGS_INITED;
+  m_flags = flags;
+  // don't write out nsMsgMessageFlags::New to MDB.
+  return SetUInt32Column(m_flags & ~nsMsgMessageFlags::New,
+                         m_mdb->m_flagsColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::OrFlags(uint32_t flags, uint32_t* result) {
+  if (!(m_initedValues & FLAGS_INITED)) InitFlags();
+  if ((m_flags & flags) != flags) SetFlags(m_flags | flags);
+  *result = m_flags;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::AndFlags(uint32_t flags, uint32_t* result) {
+  if (!(m_initedValues & FLAGS_INITED)) InitFlags();
+  if ((m_flags & flags) != m_flags) SetFlags(m_flags & flags);
+  *result = m_flags;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::MarkHasAttachments(bool bHasAttachments) {
+  nsresult rv = NS_OK;
+
+  if (m_mdb) {
+    nsMsgKey key;
+    rv = GetMessageKey(&key);
+    if (NS_SUCCEEDED(rv))
+      rv = m_mdb->MarkHasAttachments(key, bHasAttachments, nullptr);
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgHdr::MarkRead(bool bRead) {
+  nsresult rv = NS_OK;
+
+  if (m_mdb) {
+    nsMsgKey key;
+    rv = GetMessageKey(&key);
+    if (NS_SUCCEEDED(rv)) rv = m_mdb->MarkRead(key, bRead, nullptr);
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgHdr::MarkFlagged(bool bFlagged) {
+  nsresult rv = NS_OK;
+
+  if (m_mdb) {
+    nsMsgKey key;
+    rv = GetMessageKey(&key);
+    if (NS_SUCCEEDED(rv)) rv = m_mdb->MarkMarked(key, bFlagged, nullptr);
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgHdr::SetStringProperty(const char* propertyName,
+                                          const nsACString& propertyValue) {
+  NS_ENSURE_ARG_POINTER(propertyName);
+  if (!m_mdb || !m_mdbRow) return NS_ERROR_NULL_POINTER;
+  return m_mdb->SetProperty(m_mdbRow, propertyName,
+                            PromiseFlatCString(propertyValue).get());
+}
+
+NS_IMETHODIMP nsMsgHdr::GetStringProperty(const char* propertyName,
+                                          nsACString& aPropertyValue) {
+  NS_ENSURE_ARG_POINTER(propertyName);
+  if (!m_mdb || !m_mdbRow) return NS_ERROR_NULL_POINTER;
+  return m_mdb->GetProperty(m_mdbRow, propertyName,
+                            getter_Copies(aPropertyValue));
+}
+
+NS_IMETHODIMP nsMsgHdr::GetUint32Property(const char* propertyName,
+                                          uint32_t* pResult) {
+  NS_ENSURE_ARG_POINTER(propertyName);
+  if (!m_mdb || !m_mdbRow) return NS_ERROR_NULL_POINTER;
+  return m_mdb->GetUint32Property(m_mdbRow, propertyName, pResult);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetUint32Property(const char* propertyName,
+                                          uint32_t value) {
+  NS_ENSURE_ARG_POINTER(propertyName);
+  if (!m_mdb || !m_mdbRow) return NS_ERROR_NULL_POINTER;
+  return m_mdb->SetUint32Property(m_mdbRow, propertyName, value);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetNumReferences(uint16_t* result) {
+  if (!(m_initedValues & REFERENCES_INITED)) {
+    const char* references;
+    if (NS_SUCCEEDED(m_mdb->RowCellColumnToConstCharPtr(
+            GetMDBRow(), m_mdb->m_referencesColumnToken, &references)))
+      ParseReferences(references);
+    m_initedValues |= REFERENCES_INITED;
+  }
+
+  if (result) *result = m_references.Length();
+  // there is no real failure here; if there are no references, there are no
+  //  references.
+  return NS_OK;
+}
+
+nsresult nsMsgHdr::ParseReferences(const char* references) {
+  const char* startNextRef = references;
+  nsAutoCString resultReference;
+  nsCString messageId;
+  GetMessageId(getter_Copies(messageId));
+
+  while (startNextRef && *startNextRef) {
+    startNextRef = GetNextReference(startNextRef, resultReference,
+                                    startNextRef == references);
+    // Don't add self-references.
+    if (!resultReference.IsEmpty() && !resultReference.Equals(messageId))
+      m_references.AppendElement(resultReference);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetStringReference(int32_t refNum,
+                                           nsACString& resultReference) {
+  nsresult err = NS_OK;
+
+  if (!(m_initedValues & REFERENCES_INITED))
+    GetNumReferences(nullptr);  // it can handle the null
+
+  if ((uint32_t)refNum < m_references.Length())
+    resultReference = m_references.ElementAt(refNum);
+  else
+    err = NS_ERROR_ILLEGAL_VALUE;
+  return err;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetDate(PRTime* result) {
+  if (!(m_initedValues & CACHED_VALUES_INITED)) InitCachedValues();
+
+  *result = m_date;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetDateInSeconds(uint32_t* aResult) {
+  return GetUInt32Column(m_mdb->m_dateColumnToken, aResult);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetMessageId(const char* messageId) {
+  if (messageId && *messageId == '<') {
+    nsAutoCString tempMessageID(messageId + 1);
+    if (tempMessageID.CharAt(tempMessageID.Length() - 1) == '>')
+      tempMessageID.SetLength(tempMessageID.Length() - 1);
+    return SetStringColumn(tempMessageID.get(), m_mdb->m_messageIdColumnToken);
+  }
+  return SetStringColumn(messageId, m_mdb->m_messageIdColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetSubject(const nsACString& subject) {
+  return SetStringColumn(PromiseFlatCString(subject).get(),
+                         m_mdb->m_subjectColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetAuthor(const char* author) {
+  return SetStringColumn(author, m_mdb->m_senderColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetReferences(const nsACString& references) {
+  m_references.Clear();
+  ParseReferences(PromiseFlatCString(references).get());
+
+  m_initedValues |= REFERENCES_INITED;
+
+  return SetStringColumn(PromiseFlatCString(references).get(),
+                         m_mdb->m_referencesColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetRecipients(const char* recipients) {
+  // need to put in rfc822 address parsing code here (or make caller do it...)
+  return SetStringColumn(recipients, m_mdb->m_recipientsColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetCcList(const char* ccList) {
+  return SetStringColumn(ccList, m_mdb->m_ccListColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetBccList(const char* bccList) {
+  return SetStringColumn(bccList, m_mdb->m_bccListColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetMessageSize(uint32_t messageSize) {
+  SetUInt32Column(messageSize, m_mdb->m_messageSizeColumnToken);
+  m_messageSize = messageSize;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetOfflineMessageSize(uint32_t* result) {
+  uint32_t size;
+  nsresult res = GetUInt32Column(m_mdb->m_offlineMessageSizeColumnToken, &size);
+
+  *result = size;
+  return res;
+}
+
+NS_IMETHODIMP nsMsgHdr::SetOfflineMessageSize(uint32_t messageSize) {
+  return SetUInt32Column(messageSize, m_mdb->m_offlineMessageSizeColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetLineCount(uint32_t lineCount) {
+  SetUInt32Column(lineCount, m_mdb->m_numLinesColumnToken);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::SetDate(PRTime date) {
+  m_date = date;
+  uint32_t seconds;
+  PRTime2Seconds(date, &seconds);
+  return SetUInt32Column((uint32_t)seconds, m_mdb->m_dateColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetPriority(nsMsgPriorityValue priority) {
+  SetUInt32Column((uint32_t)priority, m_mdb->m_priorityColumnToken);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetPriority(nsMsgPriorityValue* result) {
+  if (!result) return NS_ERROR_NULL_POINTER;
+
+  uint32_t priority = 0;
+  nsresult rv = GetUInt32Column(m_mdb->m_priorityColumnToken, &priority);
+  if (NS_FAILED(rv)) return rv;
+
+  *result = (nsMsgPriorityValue)priority;
+  return NS_OK;
+}
+
+// I'd like to not store the account key, if the msg is in
+// the same account as it was received in, to save disk space and memory.
+// This might be problematic when a message gets moved...
+// And I'm not sure if we should short circuit it here,
+// or at a higher level where it might be more efficient.
+NS_IMETHODIMP nsMsgHdr::SetAccountKey(const char* aAccountKey) {
+  return SetStringProperty("account", nsDependentCString(aAccountKey));
+}
+
+NS_IMETHODIMP nsMsgHdr::GetAccountKey(char** aResult) {
+  NS_ENSURE_ARG_POINTER(aResult);
+
+  nsCString key;
+  nsresult rv = GetStringProperty("account", key);
+  NS_ENSURE_SUCCESS(rv, rv);
+  *aResult = ToNewCString(key);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetMessageOffset(uint64_t* result) {
+  NS_ENSURE_ARG(result);
+
+  (void)GetUInt64Column(m_mdb->m_offlineMsgOffsetColumnToken, result,
+                        (unsigned)-1);
+  if (*result == (unsigned)-1) {
+    // It's unset. Unfortunately there's not much we can do here. There's
+    // a lot of code which relies on being able to read .messageOffset,
+    // even if it doesn't require it to return anything sensible.
+    // (For example - in js unit tests - Assert.equals() stringifies the
+    // attributes of it's expected/actual values to produce an error
+    // message even if the assert passes).
+#ifdef DEBUG
+    nsCString tok;
+    GetStringProperty("storeToken", tok);
+    nsPrintfCString err("Missing .messageOffset (key=%u, storeToken='%s')",
+                        m_messageKey, tok.get());
+    NS_WARNING(err.get());
+#endif
+    // Return something obviously broken.
+    *result = 12345678;
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::SetMessageOffset(uint64_t offset) {
+  SetUInt64Column(offset, m_mdb->m_offlineMsgOffsetColumnToken);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetMessageSize(uint32_t* result) {
+  uint32_t size;
+  nsresult res = GetUInt32Column(m_mdb->m_messageSizeColumnToken, &size);
+
+  *result = size;
+  return res;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetLineCount(uint32_t* result) {
+  uint32_t linecount;
+  nsresult res = GetUInt32Column(m_mdb->m_numLinesColumnToken, &linecount);
+  *result = linecount;
+  return res;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetAuthor(char** resultAuthor) {
+  return m_mdb->RowCellColumnToCharPtr(GetMDBRow(), m_mdb->m_senderColumnToken,
+                                       resultAuthor);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetSubject(nsACString& resultSubject) {
+  return m_mdb->RowCellColumnToCharPtr(GetMDBRow(), m_mdb->m_subjectColumnToken,
+                                       getter_Copies(resultSubject));
+}
+
+NS_IMETHODIMP nsMsgHdr::GetRecipients(char** resultRecipients) {
+  return m_mdb->RowCellColumnToCharPtr(
+      GetMDBRow(), m_mdb->m_recipientsColumnToken, resultRecipients);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetCcList(char** resultCCList) {
+  return m_mdb->RowCellColumnToCharPtr(GetMDBRow(), m_mdb->m_ccListColumnToken,
+                                       resultCCList);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetBccList(char** resultBCCList) {
+  return m_mdb->RowCellColumnToCharPtr(GetMDBRow(), m_mdb->m_bccListColumnToken,
+                                       resultBCCList);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetMessageId(char** resultMessageId) {
+  return m_mdb->RowCellColumnToCharPtr(
+      GetMDBRow(), m_mdb->m_messageIdColumnToken, resultMessageId);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetMime2DecodedAuthor(nsAString& resultAuthor) {
+  return m_mdb->RowCellColumnToMime2DecodedString(
+      GetMDBRow(), m_mdb->m_senderColumnToken, resultAuthor);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetMime2DecodedSubject(nsAString& resultSubject) {
+  return m_mdb->RowCellColumnToMime2DecodedString(
+      GetMDBRow(), m_mdb->m_subjectColumnToken, resultSubject);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetMime2DecodedRecipients(nsAString& resultRecipients) {
+  return m_mdb->RowCellColumnToMime2DecodedString(
+      GetMDBRow(), m_mdb->m_recipientsColumnToken, resultRecipients);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetAuthorCollationKey(nsTArray<uint8_t>& resultAuthor) {
+  return m_mdb->RowCellColumnToAddressCollationKey(
+      GetMDBRow(), m_mdb->m_senderColumnToken, resultAuthor);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetSubjectCollationKey(
+    nsTArray<uint8_t>& resultSubject) {
+  return m_mdb->RowCellColumnToCollationKey(
+      GetMDBRow(), m_mdb->m_subjectColumnToken, resultSubject);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetRecipientsCollationKey(
+    nsTArray<uint8_t>& resultRecipients) {
+  return m_mdb->RowCellColumnToCollationKey(
+      GetMDBRow(), m_mdb->m_recipientsColumnToken, resultRecipients);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetCharset(char** aCharset) {
+  return m_mdb->RowCellColumnToCharPtr(
+      GetMDBRow(), m_mdb->m_messageCharSetColumnToken, aCharset);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetCharset(const char* aCharset) {
+  return SetStringColumn(aCharset, m_mdb->m_messageCharSetColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetEffectiveCharset(nsACString& resultCharset) {
+  return m_mdb->GetEffectiveCharset(m_mdbRow, resultCharset);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetThreadParent(nsMsgKey inKey) {
+  m_threadParent = inKey;
+  if (inKey == m_messageKey) NS_ASSERTION(false, "can't be your own parent");
+  SetUInt32Column(m_threadParent, m_mdb->m_threadParentColumnToken);
+  m_initedValues |= THREAD_PARENT_INITED;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetThreadParent(nsMsgKey* result) {
+  nsresult res;
+  if (!(m_initedValues & THREAD_PARENT_INITED)) {
+    res = GetUInt32Column(m_mdb->m_threadParentColumnToken, &m_threadParent,
+                          nsMsgKey_None);
+    if (NS_SUCCEEDED(res)) m_initedValues |= THREAD_PARENT_INITED;
+  }
+  *result = m_threadParent;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetFolder(nsIMsgFolder** result) {
+  NS_ENSURE_ARG(result);
+
+  if (m_mdb && m_mdb->m_folder) {
+    NS_ADDREF(*result = m_mdb->m_folder);
+  } else
+    *result = nullptr;
+  return NS_OK;
+}
+
+nsresult nsMsgHdr::SetStringColumn(const char* str, mdb_token token) {
+  NS_ENSURE_ARG_POINTER(str);
+  return m_mdb->CharPtrToRowCellColumn(m_mdbRow, token, str);
+}
+
+nsresult nsMsgHdr::SetUInt32Column(uint32_t value, mdb_token token) {
+  return m_mdb->UInt32ToRowCellColumn(m_mdbRow, token, value);
+}
+
+nsresult nsMsgHdr::GetUInt32Column(mdb_token token, uint32_t* pvalue,
+                                   uint32_t defaultValue) {
+  return m_mdb->RowCellColumnToUInt32(GetMDBRow(), token, pvalue, defaultValue);
+}
+
+nsresult nsMsgHdr::SetUInt64Column(uint64_t value, mdb_token token) {
+  return m_mdb->UInt64ToRowCellColumn(m_mdbRow, token, value);
+}
+
+nsresult nsMsgHdr::GetUInt64Column(mdb_token token, uint64_t* pvalue,
+                                   uint64_t defaultValue) {
+  return m_mdb->RowCellColumnToUInt64(GetMDBRow(), token, pvalue, defaultValue);
+}
+
+/**
+ * Roughly speaking, get the next message-id (starts with a '<' ends with a
+ *  '>').  Except, we also try to handle the case where your reference is of
+ *  a prehistoric vintage that just stuck any old random junk in there.  Our
+ *  old logic would (unintentionally?) just trim the whitespace off the front
+ *  and hand you everything after that.  We change things at all because that
+ *  same behaviour does not make sense if we have already seen a proper message
+ *  id.  We keep the old behaviour at all because it would seem to have
+ *  benefits.  (See jwz's non-zero stats: http://www.jwz.org/doc/threading.html)
+ * So, to re-state, if there is a valid message-id in there at all, we only
+ *  return valid message-id's (sans bracketing '<' and '>').  If there isn't,
+ *  our result (via "references") is a left-trimmed copy of the string.  If
+ *  there is nothing in there, our result is an empty string.)  We do require
+ *  that you pass allowNonDelimitedReferences what it demands, though.
+ * For example: "<valid@stuff> this stuff is invalid" would net you
+ *  "valid@stuff" and "this stuff is invalid" as results.  We now only would
+ *  provide "valid-stuff" and an empty string (which you should ignore) as
+ *  results.  However "this stuff is invalid" would return itself, allowing
+ *  anything relying on that behaviour to keep working.
+ *
+ * Note: We accept anything inside the '<' and '>'; technically, we should want
+ *  at least a '@' in there (per rfc 2822).  But since we're going out of our
+ *  way to support weird things...
+ *
+ * @param startNextRef The position to start at; this should either be the start
+ *     of your references string or our return value from a previous call.
+ * @param reference You pass a nsCString by reference, we put the reference we
+ *     find in it, if we find one.  It may be empty!  Beware!
+ * @param allowNonDelimitedReferences Should we support the
+ *     pre-reasonable-standards form of In-Reply-To where it could be any
+ *     arbitrary string and our behaviour was just to take off leading
+ *     whitespace.  It only makes sense to pass true for your first call to this
+ *     function, as if you are around to make a second call, it means we found
+ *     a properly formatted message-id and so we should only look for more
+ *     properly formatted message-ids.
+ *     NOTE: this option will also strip off a single leading '<' if there is
+ *     one. Some examples:
+ *        "   foo" => "foo"
+ *        "  <bar" => "bar"
+ *        "<<<foo" => "<<foo"
+ *        "<foo@bar>" => "foo@bar"  (completed message-id)
+ * @returns The next starting position of this routine, which may be pointing at
+ *     a nul '\0' character to indicate termination.
+ */
+const char* nsMsgHdr::GetNextReference(const char* startNextRef,
+                                       nsCString& reference,
+                                       bool acceptNonDelimitedReferences) {
+  const char* ptr = startNextRef;
+  const char* whitespaceEndedAt = nullptr;
+  const char* firstMessageIdChar = nullptr;
+
+  // make the reference result string empty by default; we will set it to
+  //  something valid if the time comes.
+  reference.Truncate();
+
+  // walk until we find a '<', but keep track of the first point we found that
+  //  was not whitespace (as defined by previous versions of this code.)
+  for (bool foundLessThan = false; !foundLessThan; ptr++) {
+    switch (*ptr) {
+      case '\0':
+        // if we are at the end of the string, we found some non-whitespace, and
+        //  the caller requested that we accept non-delimited whitespace,
+        //  give them that as their reference.  (otherwise, leave it empty)
+        if (acceptNonDelimitedReferences && whitespaceEndedAt)
+          reference = whitespaceEndedAt;
+        return ptr;
+      case ' ':
+      case '\r':
+      case '\n':
+      case '\t':
+        // do nothing, make default case mean you didn't get whitespace
+        break;
+      case '<':
+        firstMessageIdChar = ptr + 1;  // skip over the '<'
+        foundLessThan = true;          // (flag to stop)
+        // Ensure whitespaceEndedAt skips the leading '<' and is set to
+        //  a non-NULL value, just in case the message-id is not valid (no '>')
+        //  and the old-school support is desired.
+        if (!whitespaceEndedAt) whitespaceEndedAt = ptr + 1;
+        break;
+      default:
+        if (!whitespaceEndedAt) whitespaceEndedAt = ptr;
+        break;
+    }
+  }
+
+  // keep going until we hit a '>' or hit the end of the string
+  for (; *ptr; ptr++) {
+    if (*ptr == '>') {
+      // it's valid, update reference, making sure to stop before the '>'
+      reference.Assign(firstMessageIdChar, ptr - firstMessageIdChar);
+      // and return a start point just after the '>'
+      return ++ptr;
+    }
+  }
+
+  // we did not have a fully-formed, valid message-id, so consider falling back
+  if (acceptNonDelimitedReferences && whitespaceEndedAt)
+    reference = whitespaceEndedAt;
+  return ptr;
+}
+
+bool nsMsgHdr::IsParentOf(nsIMsgDBHdr* possibleChild) {
+  uint16_t referenceToCheck = 0;
+  possibleChild->GetNumReferences(&referenceToCheck);
+  nsAutoCString reference;
+
+  nsCString messageId;
+  GetMessageId(getter_Copies(messageId));
+
+  while (referenceToCheck > 0) {
+    possibleChild->GetStringReference(referenceToCheck - 1, reference);
+
+    if (reference.Equals(messageId)) return true;
+    // if reference didn't match, check if this ref is for a non-existent
+    // header. If it is, continue looking at ancestors.
+    nsCOMPtr<nsIMsgDBHdr> refHdr;
+    if (!m_mdb) break;
+    (void)m_mdb->GetMsgHdrForMessageID(reference.get(), getter_AddRefs(refHdr));
+    if (refHdr) break;
+    referenceToCheck--;
+  }
+  return false;
+}
+
+bool nsMsgHdr::IsAncestorOf(nsIMsgDBHdr* possibleChild) {
+  const char* references;
+  nsMsgHdr* curHdr =
+      static_cast<nsMsgHdr*>(possibleChild);  // closed system, cast ok
+  m_mdb->RowCellColumnToConstCharPtr(
+      curHdr->GetMDBRow(), m_mdb->m_referencesColumnToken, &references);
+  if (!references) return false;
+
+  nsCString messageId;
+  // should put < > around message id to make strstr strictly match
+  GetMessageId(getter_Copies(messageId));
+  return (strstr(references, messageId.get()) != nullptr);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetIsRead(bool* isRead) {
+  NS_ENSURE_ARG_POINTER(isRead);
+  if (!(m_initedValues & FLAGS_INITED)) InitFlags();
+  *isRead = !!(m_flags & nsMsgMessageFlags::Read);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetIsFlagged(bool* isFlagged) {
+  NS_ENSURE_ARG_POINTER(isFlagged);
+  if (!(m_initedValues & FLAGS_INITED)) InitFlags();
+  *isFlagged = !!(m_flags & nsMsgMessageFlags::Marked);
+  return NS_OK;
+}
+
+void nsMsgHdr::ReparentInThread(nsIMsgThread* thread) {
+  NS_WARNING("Borked message header, attempting to fix!");
+  uint32_t numChildren;
+  thread->GetNumChildren(&numChildren);
+  // bail out early for the singleton thread case.
+  if (numChildren == 1) {
+    SetThreadParent(nsMsgKey_None);
+    return;
+  } else {
+    nsCOMPtr<nsIMsgDBHdr> curHdr;
+    // loop through thread, looking for our proper parent.
+    for (uint32_t childIndex = 0; childIndex < numChildren; childIndex++) {
+      thread->GetChildHdrAt(childIndex, getter_AddRefs(curHdr));
+      // closed system, cast ok
+      nsMsgHdr* curMsgHdr = static_cast<nsMsgHdr*>(curHdr.get());
+      if (curHdr && curMsgHdr->IsParentOf(this)) {
+        nsMsgKey curHdrKey;
+        curHdr->GetMessageKey(&curHdrKey);
+        SetThreadParent(curHdrKey);
+        return;
+      }
+    }
+    // we didn't find it. So either the root header is our parent,
+    // or we're the root.
+    nsCOMPtr<nsIMsgDBHdr> rootHdr;
+    thread->GetRootHdr(getter_AddRefs(rootHdr));
+    NS_ASSERTION(rootHdr, "thread has no root hdr - shouldn't happen");
+    if (rootHdr) {
+      nsMsgKey rootKey;
+      rootHdr->GetMessageKey(&rootKey);
+      // if we're the root, our thread parent is -1.
+      SetThreadParent(rootKey == m_messageKey ? nsMsgKey_None : rootKey);
+    }
+  }
+}
+
+bool nsMsgHdr::IsAncestorKilled(uint32_t ancestorsToCheck) {
+  if (!(m_initedValues & FLAGS_INITED)) InitFlags();
+  bool isKilled = m_flags & nsMsgMessageFlags::Ignored;
+
+  if (!isKilled) {
+    nsMsgKey threadParent;
+    GetThreadParent(&threadParent);
+
+    if (threadParent == m_messageKey) {
+      // isKilled is false by virtue of the enclosing if statement
+      NS_ERROR("Thread is parent of itself, please fix!");
+      nsCOMPtr<nsIMsgThread> thread;
+      (void)m_mdb->GetThreadContainingMsgHdr(this, getter_AddRefs(thread));
+      if (!thread) return false;
+      ReparentInThread(thread);
+      // Something's wrong, but the problem happened some time ago, so erroring
+      // out now is probably not a good idea. Ergo, we'll pretend to be OK, show
+      // the user the thread (err on the side of caution), and let the assertion
+      // alert debuggers to a problem.
+      return false;
+    }
+    if (threadParent != nsMsgKey_None) {
+      nsCOMPtr<nsIMsgDBHdr> parentHdr;
+      (void)m_mdb->GetMsgHdrForKey(threadParent, getter_AddRefs(parentHdr));
+
+      if (parentHdr) {
+        // More proofing against crashers. This crasher was derived from the
+        // fact that something got borked, leaving is in hand with a circular
+        // reference to borked headers inducing these loops. The defining
+        // characteristic of these headers is that they don't actually seat
+        // themselves in the thread properly.
+        nsCOMPtr<nsIMsgThread> thread;
+        (void)m_mdb->GetThreadContainingMsgHdr(this, getter_AddRefs(thread));
+        if (thread) {
+          nsCOMPtr<nsIMsgDBHdr> claimant;
+          (void)thread->GetChild(threadParent, getter_AddRefs(claimant));
+          if (!claimant) {
+            // attempt to reparent, and say the thread isn't killed,
+            // erring on the side of safety.
+            ReparentInThread(thread);
+            return false;
+          }
+        }
+
+        if (!ancestorsToCheck) {
+          // We think we have a parent, but we have no more ancestors to check
+          NS_ASSERTION(false, "cycle in parent relationship, please fix!");
+          return false;
+        }
+        // closed system, cast ok
+        nsMsgHdr* parent = static_cast<nsMsgHdr*>(parentHdr.get());
+        return parent->IsAncestorKilled(ancestorsToCheck - 1);
+      }
+    }
+  }
+  return isKilled;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetIsKilled(bool* isKilled) {
+  NS_ENSURE_ARG_POINTER(isKilled);
+  *isKilled = false;
+  nsCOMPtr<nsIMsgThread> thread;
+  (void)m_mdb->GetThreadContainingMsgHdr(this, getter_AddRefs(thread));
+  // if we can't find the thread, let's at least check one level; maybe
+  // the header hasn't been added to a thread yet.
+  uint32_t numChildren = 1;
+  if (thread) thread->GetNumChildren(&numChildren);
+  if (!numChildren) return NS_ERROR_FAILURE;
+  // We can't have as many ancestors as there are messages in the thread,
+  // so tell IsAncestorKilled to only check numChildren - 1 ancestors.
+  *isKilled = IsAncestorKilled(numChildren - 1);
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+#include "nsIStringEnumerator.h"
+#define NULL_MORK_COLUMN 0
+class nsMsgPropertyEnumerator : public nsStringEnumeratorBase {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIUTF8STRINGENUMERATOR
+
+  using nsStringEnumeratorBase::GetNext;
+
+  explicit nsMsgPropertyEnumerator(nsMsgHdr* aHdr);
+  void PrefetchNext();
+
+ protected:
+  virtual ~nsMsgPropertyEnumerator();
+  nsCOMPtr<nsIMdbRowCellCursor> mRowCellCursor;
+  nsCOMPtr<nsIMdbEnv> m_mdbEnv;
+  nsCOMPtr<nsIMdbStore> m_mdbStore;
+  // Hold a reference to the hdr so it will hold an xpcom reference to the
+  // underlying mdb row. The row cell cursor will crash if the underlying
+  // row goes away.
+  RefPtr<nsMsgHdr> m_hdr;
+  bool mNextPrefetched;
+  mdb_column mNextColumn;
+};
+
+nsMsgPropertyEnumerator::nsMsgPropertyEnumerator(nsMsgHdr* aHdr)
+    : mNextPrefetched(false), mNextColumn(NULL_MORK_COLUMN) {
+  RefPtr<nsMsgDatabase> mdb;
+  nsCOMPtr<nsIMdbRow> mdbRow;
+
+  if (aHdr && (mdbRow = aHdr->GetMDBRow()) && (m_hdr = aHdr) &&
+      (mdb = aHdr->GetMdb()) && (m_mdbEnv = mdb->m_mdbEnv) &&
+      (m_mdbStore = mdb->m_mdbStore)) {
+    mdbRow->GetRowCellCursor(m_mdbEnv, -1, getter_AddRefs(mRowCellCursor));
+  }
+}
+
+nsMsgPropertyEnumerator::~nsMsgPropertyEnumerator() {
+  // Need to clear this before the nsMsgHdr and its corresponding
+  // nsIMdbRow potentially go away.
+  mRowCellCursor = nullptr;
+}
+
+NS_IMPL_ISUPPORTS(nsMsgPropertyEnumerator, nsIUTF8StringEnumerator,
+                  nsIStringEnumerator)
+
+NS_IMETHODIMP nsMsgPropertyEnumerator::GetNext(nsACString& aItem) {
+  PrefetchNext();
+  if (mNextColumn == NULL_MORK_COLUMN)
+    return NS_ERROR_FAILURE;  // call HasMore first
+  if (!m_mdbStore || !m_mdbEnv) return NS_ERROR_NOT_INITIALIZED;
+  mNextPrefetched = false;
+  char columnName[100];
+  struct mdbYarn colYarn = {columnName, 0, sizeof(columnName), 0, 0, nullptr};
+  // Get the column of the cell
+  nsresult rv = m_mdbStore->TokenToString(m_mdbEnv, mNextColumn, &colYarn);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  aItem.Assign(static_cast<char*>(colYarn.mYarn_Buf), colYarn.mYarn_Fill);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgPropertyEnumerator::HasMore(bool* aResult) {
+  NS_ENSURE_ARG_POINTER(aResult);
+
+  PrefetchNext();
+  *aResult = (mNextColumn != NULL_MORK_COLUMN);
+  return NS_OK;
+}
+
+void nsMsgPropertyEnumerator::PrefetchNext(void) {
+  if (!mNextPrefetched && m_mdbEnv && mRowCellCursor) {
+    mNextPrefetched = true;
+    nsCOMPtr<nsIMdbCell> cell;
+    mRowCellCursor->NextCell(m_mdbEnv, getter_AddRefs(cell), &mNextColumn,
+                             nullptr);
+    if (mNextColumn == NULL_MORK_COLUMN) {
+      // free up references
+      m_mdbStore = nullptr;
+      m_mdbEnv = nullptr;
+      mRowCellCursor = nullptr;
+    }
+  }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+NS_IMETHODIMP nsMsgHdr::GetProperties(nsTArray<nsCString>& headers) {
+  nsCOMPtr<nsIUTF8StringEnumerator> propertyEnumerator =
+      new nsMsgPropertyEnumerator(this);
+  bool hasMore;
+  while (NS_SUCCEEDED(propertyEnumerator->HasMore(&hasMore)) && hasMore) {
+    nsAutoCString property;
+    propertyEnumerator->GetNext(property);
+    headers.AppendElement(property);
+  }
+  return NS_OK;
+}
diff --git a/comm/mailnews/db/msgdb/src/nsMsgOfflineImapOperation.cpp b/comm/mailnews/db/msgdb/src/nsMsgOfflineImapOperation.cpp
new file mode 100644
index 0000000000..96410654d8
--- /dev/null
+++ b/comm/mailnews/db/msgdb/src/nsMsgOfflineImapOperation.cpp
@@ -0,0 +1,385 @@
+/* -*- 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 "msgCore.h"
+#include "nsMsgOfflineImapOperation.h"
+#include "nsMsgUtils.h"
+#include "mozilla/Logging.h"
+
+using namespace mozilla;
+
+LazyLogModule IMAPOffline("IMAPOffline");
+
+/* Implementation file */
+NS_IMPL_ISUPPORTS(nsMsgOfflineImapOperation, nsIMsgOfflineImapOperation)
+
+// property names for offine imap operation fields.
+#define PROP_OPERATION "op"
+#define PROP_OPERATION_FLAGS "opFlags"
+#define PROP_NEW_FLAGS "newFlags"
+#define PROP_MESSAGE_KEY "msgKey"
+#define PROP_SRC_MESSAGE_KEY "srcMsgKey"
+#define PROP_SRC_FOLDER_URI "srcFolderURI"
+#define PROP_MOVE_DEST_FOLDER_URI "moveDest"
+#define PROP_NUM_COPY_DESTS "numCopyDests"
+#define PROP_COPY_DESTS \
+  "copyDests"  // how to delimit these? Or should we do the "dest1","dest2" etc
+               // trick? But then we'd need to shuffle them around since we
+               // delete off the front first.
+#define PROP_KEYWORD_ADD "addedKeywords"
+#define PROP_KEYWORD_REMOVE "removedKeywords"
+#define PROP_MSG_SIZE "msgSize"
+#define PROP_PLAYINGBACK "inPlayback"
+
+nsMsgOfflineImapOperation::nsMsgOfflineImapOperation(nsMsgDatabase* db,
+                                                     nsIMdbRow* row) {
+  NS_ASSERTION(db, "can't have null db");
+  NS_ASSERTION(row, "can't have null row");
+  m_operation = 0;
+  m_operationFlags = 0;
+  m_messageKey = nsMsgKey_None;
+  m_sourceMessageKey = nsMsgKey_None;
+  m_mdb = db;
+  NS_ADDREF(m_mdb);
+  m_mdbRow = row;
+  m_newFlags = 0;
+  m_mdb->GetUint32Property(m_mdbRow, PROP_OPERATION, (uint32_t*)&m_operation,
+                           0);
+  m_mdb->GetUint32Property(m_mdbRow, PROP_MESSAGE_KEY, &m_messageKey, 0);
+  m_mdb->GetUint32Property(m_mdbRow, PROP_OPERATION_FLAGS, &m_operationFlags,
+                           0);
+  m_mdb->GetUint32Property(m_mdbRow, PROP_NEW_FLAGS, (uint32_t*)&m_newFlags, 0);
+}
+
+nsMsgOfflineImapOperation::~nsMsgOfflineImapOperation() {
+  // clear the row first, in case we're holding the last reference
+  // to the db.
+  m_mdbRow = nullptr;
+  NS_IF_RELEASE(m_mdb);
+}
+
+/* attribute nsOfflineImapOperationType operation; */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetOperation(
+    nsOfflineImapOperationType* aOperation) {
+  NS_ENSURE_ARG(aOperation);
+  *aOperation = m_operation;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::SetOperation(
+    nsOfflineImapOperationType aOperation) {
+  if (MOZ_LOG_TEST(IMAPOffline, LogLevel::Info))
+    MOZ_LOG(IMAPOffline, LogLevel::Info,
+            ("msg id %x setOperation was %x add %x", m_messageKey, m_operation,
+             aOperation));
+
+  m_operation |= aOperation;
+  return m_mdb->SetUint32Property(m_mdbRow, PROP_OPERATION, m_operation);
+}
+
+/* void clearOperation (in nsOfflineImapOperationType operation); */
+NS_IMETHODIMP nsMsgOfflineImapOperation::ClearOperation(
+    nsOfflineImapOperationType aOperation) {
+  if (MOZ_LOG_TEST(IMAPOffline, LogLevel::Info))
+    MOZ_LOG(IMAPOffline, LogLevel::Info,
+            ("msg id %x clearOperation was %x clear %x", m_messageKey,
+             m_operation, aOperation));
+  m_operation &= ~aOperation;
+  switch (aOperation) {
+    case kMsgMoved:
+    case kAppendTemplate:
+    case kAppendDraft:
+      m_moveDestination.Truncate();
+      break;
+    case kMsgCopy:
+      m_copyDestinations.RemoveElementAt(0);
+      break;
+  }
+  return m_mdb->SetUint32Property(m_mdbRow, PROP_OPERATION, m_operation);
+}
+
+/* attribute nsMsgKey messageKey; */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetMessageKey(nsMsgKey* aMessageKey) {
+  NS_ENSURE_ARG(aMessageKey);
+  *aMessageKey = m_messageKey;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::SetMessageKey(nsMsgKey aMessageKey) {
+  m_messageKey = aMessageKey;
+  return m_mdb->SetUint32Property(m_mdbRow, PROP_MESSAGE_KEY, m_messageKey);
+}
+
+/* attribute nsMsgKey srcMessageKey; */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetSrcMessageKey(
+    nsMsgKey* aMessageKey) {
+  NS_ENSURE_ARG(aMessageKey);
+  return m_mdb->GetUint32Property(m_mdbRow, PROP_SRC_MESSAGE_KEY, aMessageKey,
+                                  nsMsgKey_None);
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::SetSrcMessageKey(
+    nsMsgKey aMessageKey) {
+  m_messageKey = aMessageKey;
+  return m_mdb->SetUint32Property(m_mdbRow, PROP_SRC_MESSAGE_KEY, m_messageKey);
+}
+
+/* attribute imapMessageFlagsType flagOperation; */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetFlagOperation(
+    imapMessageFlagsType* aFlagOperation) {
+  NS_ENSURE_ARG(aFlagOperation);
+  *aFlagOperation = m_operationFlags;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::SetFlagOperation(
+    imapMessageFlagsType aFlagOperation) {
+  if (MOZ_LOG_TEST(IMAPOffline, LogLevel::Info))
+    MOZ_LOG(IMAPOffline, LogLevel::Info,
+            ("msg id %x setFlagOperation was %x add %x", m_messageKey,
+             m_operationFlags, aFlagOperation));
+  SetOperation(kFlagsChanged);
+  nsresult rv = SetNewFlags(aFlagOperation);
+  NS_ENSURE_SUCCESS(rv, rv);
+  m_operationFlags |= aFlagOperation;
+  return m_mdb->SetUint32Property(m_mdbRow, PROP_OPERATION_FLAGS,
+                                  m_operationFlags);
+}
+
+/* attribute imapMessageFlagsType flagOperation; */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetNewFlags(
+    imapMessageFlagsType* aNewFlags) {
+  NS_ENSURE_ARG(aNewFlags);
+  uint32_t flags;
+  nsresult rv = m_mdb->GetUint32Property(m_mdbRow, PROP_NEW_FLAGS, &flags, 0);
+  *aNewFlags = m_newFlags = (imapMessageFlagsType)flags;
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::SetNewFlags(
+    imapMessageFlagsType aNewFlags) {
+  if (MOZ_LOG_TEST(IMAPOffline, LogLevel::Info) && m_newFlags != aNewFlags)
+    MOZ_LOG(IMAPOffline, LogLevel::Info,
+            ("msg id %x SetNewFlags was %x to %x", m_messageKey, m_newFlags,
+             aNewFlags));
+  m_newFlags = aNewFlags;
+  return m_mdb->SetUint32Property(m_mdbRow, PROP_NEW_FLAGS, m_newFlags);
+}
+
+/* attribute string destinationFolderURI; */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetDestinationFolderURI(
+    nsACString& aDestinationFolderURI) {
+  (void)m_mdb->GetProperty(m_mdbRow, PROP_MOVE_DEST_FOLDER_URI,
+                           getter_Copies(m_moveDestination));
+  aDestinationFolderURI = m_moveDestination;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::SetDestinationFolderURI(
+    const nsACString& aDestinationFolderURI) {
+  if (MOZ_LOG_TEST(IMAPOffline, LogLevel::Info))
+    MOZ_LOG(IMAPOffline, LogLevel::Info,
+            ("msg id %x SetDestinationFolderURI to %s", m_messageKey,
+             PromiseFlatCString(aDestinationFolderURI).get()));
+  m_moveDestination = aDestinationFolderURI;
+  return m_mdb->SetProperty(m_mdbRow, PROP_MOVE_DEST_FOLDER_URI,
+                            PromiseFlatCString(aDestinationFolderURI).get());
+}
+
+/* attribute string sourceFolderURI; */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetSourceFolderURI(
+    nsACString& aSourceFolderURI) {
+  nsresult rv = m_mdb->GetProperty(m_mdbRow, PROP_SRC_FOLDER_URI,
+                                   getter_Copies(m_sourceFolder));
+  aSourceFolderURI = m_sourceFolder;
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::SetSourceFolderURI(
+    const nsACString& aSourceFolderURI) {
+  m_sourceFolder = aSourceFolderURI;
+  SetOperation(kMoveResult);
+
+  return m_mdb->SetProperty(m_mdbRow, PROP_SRC_FOLDER_URI,
+                            PromiseFlatCString(aSourceFolderURI).get());
+}
+
+/* attribute string keyword; */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetKeywordsToAdd(char** aKeywords) {
+  NS_ENSURE_ARG(aKeywords);
+  nsresult rv = m_mdb->GetProperty(m_mdbRow, PROP_KEYWORD_ADD,
+                                   getter_Copies(m_keywordsToAdd));
+  *aKeywords = ToNewCString(m_keywordsToAdd);
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::AddKeywordToAdd(const char* aKeyword) {
+  SetOperation(kAddKeywords);
+  return AddKeyword(aKeyword, m_keywordsToAdd, PROP_KEYWORD_ADD,
+                    m_keywordsToRemove, PROP_KEYWORD_REMOVE);
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetKeywordsToRemove(char** aKeywords) {
+  NS_ENSURE_ARG(aKeywords);
+  nsresult rv = m_mdb->GetProperty(m_mdbRow, PROP_KEYWORD_REMOVE,
+                                   getter_Copies(m_keywordsToRemove));
+  *aKeywords = ToNewCString(m_keywordsToRemove);
+  return rv;
+}
+
+nsresult nsMsgOfflineImapOperation::AddKeyword(const char* aKeyword,
+                                               nsCString& addList,
+                                               const char* addProp,
+                                               nsCString& removeList,
+                                               const char* removeProp) {
+  int32_t startOffset, keywordLength;
+  if (!MsgFindKeyword(nsDependentCString(aKeyword), addList, &startOffset,
+                      &keywordLength)) {
+    if (!addList.IsEmpty()) addList.Append(' ');
+    addList.Append(aKeyword);
+  }
+  // if the keyword we're removing was in the list of keywords to add,
+  // cut it from that list.
+  if (MsgFindKeyword(nsDependentCString(aKeyword), removeList, &startOffset,
+                     &keywordLength)) {
+    removeList.Cut(startOffset, keywordLength);
+    m_mdb->SetProperty(m_mdbRow, removeProp, removeList.get());
+  }
+  return m_mdb->SetProperty(m_mdbRow, addProp, addList.get());
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::AddKeywordToRemove(
+    const char* aKeyword) {
+  SetOperation(kRemoveKeywords);
+  return AddKeyword(aKeyword, m_keywordsToRemove, PROP_KEYWORD_REMOVE,
+                    m_keywordsToAdd, PROP_KEYWORD_ADD);
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::AddMessageCopyOperation(
+    const nsACString& destinationBox) {
+  SetOperation(kMsgCopy);
+  nsresult rv = GetCopiesFromDB();
+  NS_ENSURE_SUCCESS(rv, rv);
+  m_copyDestinations.AppendElement(destinationBox);
+  return SetCopiesToDB();
+}
+
+// we write out the folders as one string, separated by 0x1.
+#define FOLDER_SEP_CHAR '\001'
+
+nsresult nsMsgOfflineImapOperation::GetCopiesFromDB() {
+  nsCString copyDests;
+  m_copyDestinations.Clear();
+  nsresult rv =
+      m_mdb->GetProperty(m_mdbRow, PROP_COPY_DESTS, getter_Copies(copyDests));
+  // use 0x1 as the delimiter between folder names since it's not a legal
+  // character
+  if (NS_SUCCEEDED(rv) && !copyDests.IsEmpty()) {
+    int32_t curCopyDestStart = 0;
+    int32_t nextCopyDestPos = 0;
+
+    while (nextCopyDestPos != -1) {
+      nsCString curDest;
+      nextCopyDestPos = copyDests.FindChar(FOLDER_SEP_CHAR, curCopyDestStart);
+      if (nextCopyDestPos > 0)
+        curDest = Substring(copyDests, curCopyDestStart,
+                            nextCopyDestPos - curCopyDestStart);
+      else
+        curDest = Substring(copyDests, curCopyDestStart,
+                            copyDests.Length() - curCopyDestStart);
+      curCopyDestStart = nextCopyDestPos + 1;
+      m_copyDestinations.AppendElement(curDest);
+    }
+  }
+  return rv;
+}
+
+nsresult nsMsgOfflineImapOperation::SetCopiesToDB() {
+  nsAutoCString copyDests;
+
+  // use 0x1 as the delimiter between folders
+  for (uint32_t i = 0; i < m_copyDestinations.Length(); i++) {
+    if (i > 0) copyDests.Append(FOLDER_SEP_CHAR);
+    copyDests.Append(m_copyDestinations.ElementAt(i));
+  }
+  return m_mdb->SetProperty(m_mdbRow, PROP_COPY_DESTS, copyDests.get());
+}
+
+/* attribute long numberOfCopies; */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetNumberOfCopies(
+    int32_t* aNumberOfCopies) {
+  NS_ENSURE_ARG(aNumberOfCopies);
+  nsresult rv = GetCopiesFromDB();
+  NS_ENSURE_SUCCESS(rv, rv);
+  *aNumberOfCopies = m_copyDestinations.Length();
+  return NS_OK;
+}
+
+/* string getCopyDestination (in long copyIndex); */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetCopyDestination(int32_t copyIndex,
+                                                            char** retval) {
+  NS_ENSURE_ARG(retval);
+  nsresult rv = GetCopiesFromDB();
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (copyIndex >= (int32_t)m_copyDestinations.Length())
+    return NS_ERROR_ILLEGAL_VALUE;
+  *retval = ToNewCString(m_copyDestinations.ElementAt(copyIndex));
+  return (*retval) ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
+}
+
+/* attribute unsigned log msgSize; */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetMsgSize(uint32_t* aMsgSize) {
+  NS_ENSURE_ARG(aMsgSize);
+  return m_mdb->GetUint32Property(m_mdbRow, PROP_MSG_SIZE, aMsgSize, 0);
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::SetMsgSize(uint32_t aMsgSize) {
+  return m_mdb->SetUint32Property(m_mdbRow, PROP_MSG_SIZE, aMsgSize);
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::SetPlayingBack(bool aPlayingBack) {
+  return m_mdb->SetBooleanProperty(m_mdbRow, PROP_PLAYINGBACK, aPlayingBack);
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetPlayingBack(bool* aPlayingBack) {
+  NS_ENSURE_ARG(aPlayingBack);
+  return m_mdb->GetBooleanProperty(m_mdbRow, PROP_PLAYINGBACK, aPlayingBack);
+}
+
+void nsMsgOfflineImapOperation::Log() {
+  if (!MOZ_LOG_TEST(IMAPOffline, LogLevel::Info)) return;
+  //  const long kMoveResult              = 0x8;
+  //  const long kAppendDraft           = 0x10;
+  //  const long kAddedHeader           = 0x20;
+  //  const long kDeletedMsg              = 0x40;
+  //  const long kMsgMarkedDeleted = 0x80;
+  //  const long kAppendTemplate      = 0x100;
+  //  const long kDeleteAllMsgs          = 0x200;
+  if (m_operation & nsIMsgOfflineImapOperation::kFlagsChanged)
+    MOZ_LOG(IMAPOffline, LogLevel::Info,
+            ("msg id %x changeFlag:%x", m_messageKey, m_newFlags));
+  if (m_operation & nsIMsgOfflineImapOperation::kMsgMoved) {
+    nsCString moveDestFolder;
+    GetDestinationFolderURI(moveDestFolder);
+    MOZ_LOG(IMAPOffline, LogLevel::Info,
+            ("msg id %x moveTo:%s", m_messageKey, moveDestFolder.get()));
+  }
+  if (m_operation & nsIMsgOfflineImapOperation::kMsgCopy) {
+    nsCString copyDests;
+    m_mdb->GetProperty(m_mdbRow, PROP_COPY_DESTS, getter_Copies(copyDests));
+    MOZ_LOG(IMAPOffline, LogLevel::Info,
+            ("msg id %x moveTo:%s", m_messageKey, copyDests.get()));
+  }
+  if (m_operation & nsIMsgOfflineImapOperation::kAppendDraft)
+    MOZ_LOG(IMAPOffline, LogLevel::Info,
+            ("msg id %x append draft", m_messageKey));
+  if (m_operation & nsIMsgOfflineImapOperation::kAddKeywords)
+    MOZ_LOG(IMAPOffline, LogLevel::Info,
+            ("msg id %x add keyword:%s", m_messageKey, m_keywordsToAdd.get()));
+  if (m_operation & nsIMsgOfflineImapOperation::kRemoveKeywords)
+    MOZ_LOG(IMAPOffline, LogLevel::Info,
+            ("msg id %x remove keyword:%s", m_messageKey,
+             m_keywordsToRemove.get()));
+}
diff --git a/comm/mailnews/db/msgdb/src/nsMsgOfflineImapOperation.h b/comm/mailnews/db/msgdb/src/nsMsgOfflineImapOperation.h
new file mode 100644
index 0000000000..ba6ad3f079
--- /dev/null
+++ b/comm/mailnews/db/msgdb/src/nsMsgOfflineImapOperation.h
@@ -0,0 +1,52 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 _nsMsgOfflineImapOperation_H_
+
+#  include "nsIMsgOfflineImapOperation.h"
+#  include "mdb.h"
+#  include "nsMsgDatabase.h"
+#  include "prlog.h"
+
+class nsMsgOfflineImapOperation : public nsIMsgOfflineImapOperation {
+ public:
+  /** Instance Methods **/
+  nsMsgOfflineImapOperation(nsMsgDatabase* db, nsIMdbRow* row);
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIMSGOFFLINEIMAPOPERATION
+
+  nsIMdbRow* GetMDBRow() { return m_mdbRow; }
+  nsresult GetCopiesFromDB();
+  nsresult SetCopiesToDB();
+  void Log();
+
+ protected:
+  virtual ~nsMsgOfflineImapOperation();
+  nsresult AddKeyword(const char* aKeyword, nsCString& addList,
+                      const char* addProp, nsCString& removeList,
+                      const char* removeProp);
+
+  nsOfflineImapOperationType m_operation;
+  nsMsgKey m_messageKey;
+  nsMsgKey m_sourceMessageKey;
+  uint32_t m_operationFlags;        // what to do on sync
+  imapMessageFlagsType m_newFlags;  // used for kFlagsChanged
+
+  // these are URI's, and are escaped. Thus, we can use a delimter like ' '
+  // because the real spaces should be escaped.
+  nsCString m_sourceFolder;
+  nsCString m_moveDestination;
+  nsTArray<nsCString> m_copyDestinations;
+
+  nsCString m_keywordsToAdd;
+  nsCString m_keywordsToRemove;
+
+  // nsMsgOfflineImapOperation will have to know what db and row they belong to,
+  // since they are really just a wrapper around the offline operation row in
+  // the mdb. though I hope not.
+  nsMsgDatabase* m_mdb;
+  nsCOMPtr<nsIMdbRow> m_mdbRow;
+};
+
+#endif /* _nsMsgOfflineImapOperation_H_ */
diff --git a/comm/mailnews/db/msgdb/src/nsMsgThread.cpp b/comm/mailnews/db/msgdb/src/nsMsgThread.cpp
new file mode 100644
index 0000000000..15398cf321
--- /dev/null
+++ b/comm/mailnews/db/msgdb/src/nsMsgThread.cpp
@@ -0,0 +1,1050 @@
+/* -*- 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 "msgCore.h"
+#include "nsMsgDatabase.h"
+#include "nsCOMPtr.h"
+#include "nsMsgThread.h"
+#include "nsMsgMessageFlags.h"
+#include "nsMsgEnumerator.h"
+#include "MailNewsTypes2.h"
+#include "mozilla/DebugOnly.h"
+
+NS_IMPL_ISUPPORTS(nsMsgThread, nsIMsgThread)
+
+nsMsgThread::nsMsgThread() { Init(); }
+
+nsMsgThread::nsMsgThread(nsMsgDatabase* db, nsIMdbTable* table) {
+  Init();
+  m_mdbTable = table;
+  m_mdbDB = db;
+  if (db)
+    db->m_threads.AppendElement(this);
+  else
+    NS_ERROR("no db for thread");
+#ifdef DEBUG_David_Bienvenu
+  if (m_mdbDB->m_threads.Length() > 5)
+    printf("more than five outstanding threads\n");
+#endif
+  if (table && db) {
+    table->GetMetaRow(db->GetEnv(), nullptr, nullptr,
+                      getter_AddRefs(m_metaRow));
+    InitCachedValues();
+  }
+}
+
+void nsMsgThread::Init() {
+  m_threadKey = nsMsgKey_None;
+  m_threadRootKey = nsMsgKey_None;
+  m_numChildren = 0;
+  m_numUnreadChildren = 0;
+  m_flags = 0;
+  m_newestMsgDate = 0;
+  m_cachedValuesInitialized = false;
+}
+
+nsMsgThread::~nsMsgThread() {
+  if (m_mdbDB) {
+    mozilla::DebugOnly<bool> found = m_mdbDB->m_threads.RemoveElement(this);
+    NS_ASSERTION(found, "removing thread not in threads array");
+  } else  // This can happen if db is forced closed
+    NS_WARNING("null db in thread");
+  Clear();
+}
+
+void nsMsgThread::Clear() {
+  m_mdbTable = nullptr;
+  m_metaRow = nullptr;
+  m_mdbDB = nullptr;
+}
+
+nsresult nsMsgThread::InitCachedValues() {
+  nsresult err = NS_OK;
+
+  NS_ENSURE_TRUE(m_mdbDB && m_metaRow, NS_ERROR_INVALID_POINTER);
+
+  if (!m_cachedValuesInitialized) {
+    err = m_mdbDB->RowCellColumnToUInt32(
+        m_metaRow, m_mdbDB->m_threadFlagsColumnToken, &m_flags);
+    err = m_mdbDB->RowCellColumnToUInt32(
+        m_metaRow, m_mdbDB->m_threadChildrenColumnToken, &m_numChildren);
+    err = m_mdbDB->RowCellColumnToUInt32(
+        m_metaRow, m_mdbDB->m_threadIdColumnToken, &m_threadKey, nsMsgKey_None);
+    err = m_mdbDB->RowCellColumnToUInt32(
+        m_metaRow, m_mdbDB->m_threadUnreadChildrenColumnToken,
+        &m_numUnreadChildren);
+    err = m_mdbDB->RowCellColumnToUInt32(m_metaRow,
+                                         m_mdbDB->m_threadRootKeyColumnToken,
+                                         &m_threadRootKey, nsMsgKey_None);
+    err = m_mdbDB->RowCellColumnToUInt32(
+        m_metaRow, m_mdbDB->m_threadNewestMsgDateColumnToken, &m_newestMsgDate,
+        0);
+    // fix num children if it's wrong. this doesn't work - some DB's have a
+    // bogus thread table that is full of bogus headers - don't know why.
+    uint32_t rowCount = 0;
+    m_mdbTable->GetCount(m_mdbDB->GetEnv(), &rowCount);
+    //    NS_ASSERTION(m_numChildren <= rowCount, "num children wrong -
+    //    fixing");
+    if (m_numChildren > rowCount)
+      ChangeChildCount((int32_t)rowCount - (int32_t)m_numChildren);
+    if ((int32_t)m_numUnreadChildren < 0)
+      ChangeUnreadChildCount(-(int32_t)m_numUnreadChildren);
+    if (NS_SUCCEEDED(err)) m_cachedValuesInitialized = true;
+  }
+  return err;
+}
+
+NS_IMETHODIMP nsMsgThread::SetThreadKey(nsMsgKey threadKey) {
+  NS_ASSERTION(m_threadKey == nsMsgKey_None || m_threadKey == threadKey,
+               "shouldn't be changing thread key");
+  m_threadKey = threadKey;
+  // by definition, the initial thread key is also the thread root key.
+  SetThreadRootKey(threadKey);
+  // gotta set column in meta row here.
+  return m_mdbDB->UInt32ToRowCellColumn(
+      m_metaRow, m_mdbDB->m_threadIdColumnToken, threadKey);
+}
+
+NS_IMETHODIMP nsMsgThread::GetThreadKey(nsMsgKey* result) {
+  NS_ENSURE_ARG_POINTER(result);
+  nsresult res = m_mdbDB->RowCellColumnToUInt32(
+      m_metaRow, m_mdbDB->m_threadIdColumnToken, &m_threadKey);
+  *result = m_threadKey;
+  return res;
+}
+
+NS_IMETHODIMP nsMsgThread::GetFlags(uint32_t* result) {
+  NS_ENSURE_ARG_POINTER(result);
+  nsresult res = m_mdbDB->RowCellColumnToUInt32(
+      m_metaRow, m_mdbDB->m_threadFlagsColumnToken, &m_flags);
+  *result = m_flags;
+  return res;
+}
+
+NS_IMETHODIMP nsMsgThread::SetFlags(uint32_t flags) {
+  m_flags = flags;
+  return m_mdbDB->UInt32ToRowCellColumn(
+      m_metaRow, m_mdbDB->m_threadFlagsColumnToken, m_flags);
+}
+
+NS_IMETHODIMP nsMsgThread::SetSubject(const nsACString& aSubject) {
+  return m_mdbDB->CharPtrToRowCellColumn(m_metaRow,
+                                         m_mdbDB->m_threadSubjectColumnToken,
+                                         PromiseFlatCString(aSubject).get());
+}
+
+NS_IMETHODIMP nsMsgThread::GetSubject(nsACString& aSubject) {
+  nsCString subjectStr;
+  nsresult rv = m_mdbDB->RowCellColumnToCharPtr(
+      m_metaRow, m_mdbDB->m_threadSubjectColumnToken,
+      getter_Copies(subjectStr));
+
+  aSubject.Assign(subjectStr);
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgThread::GetNumChildren(uint32_t* result) {
+  NS_ENSURE_ARG_POINTER(result);
+  *result = m_numChildren;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgThread::GetNumUnreadChildren(uint32_t* result) {
+  NS_ENSURE_ARG_POINTER(result);
+  *result = m_numUnreadChildren;
+  return NS_OK;
+}
+
+nsresult nsMsgThread::RerootThread(nsIMsgDBHdr* newParentOfOldRoot,
+                                   nsIMsgDBHdr* oldRoot,
+                                   nsIDBChangeAnnouncer* announcer) {
+  nsresult rv = NS_OK;
+  mdb_pos outPos;
+  nsMsgKey newHdrAncestor;
+  nsCOMPtr<nsIMsgDBHdr> ancestorHdr = newParentOfOldRoot;
+  nsMsgKey newRoot;
+
+  ancestorHdr->GetMessageKey(&newRoot);
+  // loop trying to find the oldest ancestor of this msg
+  // that is a parent of the root. The oldest ancestor will
+  // become the root of the thread.
+  do {
+    ancestorHdr->GetThreadParent(&newHdrAncestor);
+    if (newHdrAncestor != nsMsgKey_None && newHdrAncestor != m_threadRootKey &&
+        newHdrAncestor != newRoot) {
+      newRoot = newHdrAncestor;
+      rv = m_mdbDB->GetMsgHdrForKey(newRoot, getter_AddRefs(ancestorHdr));
+    }
+  } while (NS_SUCCEEDED(rv) && ancestorHdr && newHdrAncestor != nsMsgKey_None &&
+           newHdrAncestor != m_threadRootKey && newHdrAncestor != newRoot);
+  SetThreadRootKey(newRoot);
+  ReparentNonReferenceChildrenOf(oldRoot, newRoot, announcer);
+  if (ancestorHdr) {
+    nsIMsgDBHdr* msgHdr = ancestorHdr;
+    nsMsgHdr* rootMsgHdr =
+        static_cast<nsMsgHdr*>(msgHdr);  // closed system, cast ok
+    nsIMdbRow* newRootHdrRow = rootMsgHdr->GetMDBRow();
+    // move the  root hdr to pos 0.
+    m_mdbTable->MoveRow(m_mdbDB->GetEnv(), newRootHdrRow, -1, 0, &outPos);
+    ancestorHdr->SetThreadParent(nsMsgKey_None);
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgThread::AddChild(nsIMsgDBHdr* child, nsIMsgDBHdr* inReplyTo,
+                                    bool threadInThread,
+                                    nsIDBChangeAnnouncer* announcer) {
+  nsresult rv = NS_OK;
+  nsMsgHdr* hdr = static_cast<nsMsgHdr*>(child);  // closed system, cast ok
+  uint32_t newHdrFlags = 0;
+  uint32_t msgDate;
+  nsMsgKey newHdrKey = 0;
+  bool parentKeyNeedsSetting = true;
+
+  nsIMdbRow* hdrRow = hdr->GetMDBRow();
+  NS_ENSURE_STATE(hdrRow);
+  hdr->GetRawFlags(&newHdrFlags);
+  hdr->GetMessageKey(&newHdrKey);
+  hdr->GetDateInSeconds(&msgDate);
+  if (msgDate > m_newestMsgDate) SetNewestMsgDate(msgDate);
+
+  if (newHdrFlags & nsMsgMessageFlags::Watched)
+    SetFlags(m_flags | nsMsgMessageFlags::Watched);
+
+  child->AndFlags(~(nsMsgMessageFlags::Watched), &newHdrFlags);
+
+  // These are threading flags that the child may have set before being added
+  // to the database.
+  uint32_t protoThreadFlags;
+  child->GetUint32Property("ProtoThreadFlags", &protoThreadFlags);
+  SetFlags(m_flags | protoThreadFlags);
+  // Clear the flag so that it doesn't fudge anywhere else
+  child->SetUint32Property("ProtoThreadFlags", 0);
+
+  uint32_t numChildren = 0;
+  // get the num children before we add the new header.
+  GetNumChildren(&numChildren);
+
+  // if this is an empty thread, set the root key to this header's key
+  if (numChildren == 0) SetThreadRootKey(newHdrKey);
+
+  if (m_mdbTable) {
+    m_mdbTable->AddRow(m_mdbDB->GetEnv(), hdrRow);
+    ChangeChildCount(1);
+    if (!(newHdrFlags & nsMsgMessageFlags::Read)) ChangeUnreadChildCount(1);
+  }
+  if (inReplyTo) {
+    nsMsgKey parentKey;
+    inReplyTo->GetMessageKey(&parentKey);
+    child->SetThreadParent(parentKey);
+    parentKeyNeedsSetting = false;
+  }
+
+  // check if this header is a parent of one of the messages in this thread
+  bool hdrMoved = false;
+  nsCOMPtr<nsIMsgDBHdr> curHdr;
+  uint32_t moveIndex = 0;
+
+  PRTime newHdrDate;
+  child->GetDate(&newHdrDate);
+
+  // This is an ugly but simple fix for a difficult problem. Basically, when we
+  // add a message to a thread, we have to run through the thread to see if the
+  // new message is a parent of an existing message in the thread, and adjust
+  // things accordingly. If you thread by subject, and you have a large folder
+  // with messages w/ all the same subject, this code can take a really long
+  // time. So the pragmatic thing is to say that for threads with more than 1000
+  // messages, it's simply not worth dealing with the case where the parent
+  // comes in after the child. Threads with more than 1000 messages are pretty
+  // unwieldy anyway. See Bug 90452
+
+  if (numChildren < 1000) {
+    for (uint32_t childIndex = 0; childIndex < numChildren; childIndex++) {
+      nsMsgKey msgKey = nsMsgKey_None;
+
+      rv = GetChildHdrAt(childIndex, getter_AddRefs(curHdr));
+      if (NS_SUCCEEDED(rv) && curHdr) {
+        if (hdr->IsParentOf(curHdr)) {
+          nsMsgKey oldThreadParent;
+          mdb_pos outPos;
+          // move this hdr before the current header.
+          if (!hdrMoved) {
+            m_mdbTable->MoveRow(m_mdbDB->GetEnv(), hdrRow, -1, childIndex,
+                                &outPos);
+            hdrMoved = true;
+            curHdr->GetThreadParent(&oldThreadParent);
+            curHdr->GetMessageKey(&msgKey);
+            nsCOMPtr<nsIMsgDBHdr> curParent;
+            m_mdbDB->GetMsgHdrForKey(oldThreadParent,
+                                     getter_AddRefs(curParent));
+            if (curParent && hdr->IsAncestorOf(curParent)) {
+              nsMsgKey curParentKey;
+              curParent->GetMessageKey(&curParentKey);
+              if (curParentKey == m_threadRootKey) {
+                m_mdbTable->MoveRow(m_mdbDB->GetEnv(), hdrRow, -1, 0, &outPos);
+                RerootThread(child, curParent, announcer);
+                parentKeyNeedsSetting = false;
+              }
+            } else if (msgKey == m_threadRootKey) {
+              RerootThread(child, curHdr, announcer);
+              parentKeyNeedsSetting = false;
+            }
+          }
+          curHdr->SetThreadParent(newHdrKey);
+          // TODO: what should be msgKey if hdrMoved was true above?
+          if (msgKey == newHdrKey) parentKeyNeedsSetting = false;
+
+          // OK, this is a reparenting - need to send notification
+          if (announcer)
+            announcer->NotifyParentChangedAll(msgKey, oldThreadParent,
+                                              newHdrKey, nullptr);
+#ifdef DEBUG_bienvenu1
+          if (newHdrKey != m_threadKey) printf("adding second level child\n");
+#endif
+        }
+        // Calculate a position for this child in date order
+        else if (!hdrMoved && childIndex > 0 && moveIndex == 0) {
+          PRTime curHdrDate;
+
+          curHdr->GetDate(&curHdrDate);
+          if (newHdrDate < curHdrDate) moveIndex = childIndex;
+        }
+      }
+    }
+  }
+  // If this header is not a reply to a header in the thread, and isn't a parent
+  // check to see if it starts with Re: - if not, and the first header does
+  // start with re, should we make this header the top level header? If it's
+  // date is less (or it's ID?), then yes.
+  if (numChildren > 0 && !(newHdrFlags & nsMsgMessageFlags::HasRe) &&
+      !inReplyTo) {
+    PRTime topLevelHdrDate;
+
+    nsCOMPtr<nsIMsgDBHdr> topLevelHdr;
+    rv = GetRootHdr(getter_AddRefs(topLevelHdr));
+    if (NS_SUCCEEDED(rv) && topLevelHdr) {
+      topLevelHdr->GetDate(&topLevelHdrDate);
+      if (newHdrDate < topLevelHdrDate) {
+        RerootThread(child, topLevelHdr, announcer);
+        mdb_pos outPos;
+        m_mdbTable->MoveRow(m_mdbDB->GetEnv(), hdrRow, -1, 0, &outPos);
+        hdrMoved = true;
+        topLevelHdr->SetThreadParent(newHdrKey);
+        parentKeyNeedsSetting = false;
+        // ### need to get ancestor of new hdr here too.
+        SetThreadRootKey(newHdrKey);
+        child->SetThreadParent(nsMsgKey_None);
+        // argh, here we'd need to adjust all the headers that listed
+        // the demoted header as their thread parent, but only because
+        // of subject threading. Adjust them to point to the new parent,
+        // that is.
+        ReparentNonReferenceChildrenOf(topLevelHdr, newHdrKey, announcer);
+      }
+    }
+  }
+  // OK, check to see if we added this header, and didn't parent it.
+
+  if (numChildren > 0 && parentKeyNeedsSetting)
+    child->SetThreadParent(m_threadRootKey);
+
+  // Move child to keep thread sorted in ascending date order
+  if (!hdrMoved && moveIndex > 0) {
+    mdb_pos outPos;
+    m_mdbTable->MoveRow(m_mdbDB->GetEnv(), hdrRow, -1, moveIndex, &outPos);
+  }
+
+  // do this after we've put the new hdr in the thread
+  bool isKilled;
+  child->GetIsKilled(&isKilled);
+  if ((m_flags & nsMsgMessageFlags::Ignored || isKilled) && m_mdbDB)
+    m_mdbDB->MarkHdrRead(child, true, nullptr);
+#ifdef DEBUG_David_Bienvenu
+  nsMsgKey msgHdrThreadKey;
+  child->GetThreadId(&msgHdrThreadKey);
+  NS_ASSERTION(msgHdrThreadKey == m_threadKey,
+               "adding msg to thread it doesn't belong to");
+#endif
+  return rv;
+}
+
+nsresult nsMsgThread::ReparentNonReferenceChildrenOf(
+    nsIMsgDBHdr* oldTopLevelHdr, nsMsgKey newParentKey,
+    nsIDBChangeAnnouncer* announcer) {
+  nsCOMPtr<nsIMsgDBHdr> curHdr;
+  uint32_t numChildren = 0;
+
+  GetNumChildren(&numChildren);
+  for (uint32_t childIndex = 0; childIndex < numChildren; childIndex++) {
+    nsMsgKey oldTopLevelHdrKey;
+
+    oldTopLevelHdr->GetMessageKey(&oldTopLevelHdrKey);
+    nsresult rv = GetChildHdrAt(childIndex, getter_AddRefs(curHdr));
+    if (NS_SUCCEEDED(rv) && curHdr) {
+      nsMsgKey oldThreadParent, curHdrKey;
+      nsMsgHdr* oldTopLevelMsgHdr =
+          static_cast<nsMsgHdr*>(oldTopLevelHdr);  // closed system, cast ok
+      curHdr->GetThreadParent(&oldThreadParent);
+      curHdr->GetMessageKey(&curHdrKey);
+      if (oldThreadParent == oldTopLevelHdrKey && curHdrKey != newParentKey &&
+          !oldTopLevelMsgHdr->IsParentOf(curHdr)) {
+        curHdr->GetThreadParent(&oldThreadParent);
+        curHdr->SetThreadParent(newParentKey);
+        // OK, this is a reparenting - need to send notification
+        if (announcer)
+          announcer->NotifyParentChangedAll(curHdrKey, oldThreadParent,
+                                            newParentKey, nullptr);
+      }
+    }
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgThread::GetChildKeyAt(uint32_t aIndex, nsMsgKey* aResult) {
+  NS_ENSURE_ARG_POINTER(aResult);
+  nsresult rv;
+
+  if (aIndex >= m_numChildren) {
+    *aResult = nsMsgKey_None;
+    return NS_ERROR_ILLEGAL_VALUE;
+  }
+  mdbOid oid;
+  rv = m_mdbTable->PosToOid(m_mdbDB->GetEnv(), aIndex, &oid);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  *aResult = oid.mOid_Id;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgThread::GetChildHdrAt(uint32_t aIndex,
+                                         nsIMsgDBHdr** result) {
+  // mork doesn't seem to handle this correctly, so deal with going off
+  // the end here.
+  if (aIndex >= m_numChildren) return NS_MSG_MESSAGE_NOT_FOUND;
+  mdbOid oid;
+  nsresult rv = m_mdbTable->PosToOid(m_mdbDB->GetEnv(), aIndex, &oid);
+  NS_ENSURE_SUCCESS(rv, NS_MSG_MESSAGE_NOT_FOUND);
+  nsIMdbRow* hdrRow = nullptr;
+  rv = m_mdbTable->PosToRow(m_mdbDB->GetEnv(), aIndex, &hdrRow);
+  NS_ENSURE_TRUE(NS_SUCCEEDED(rv) && hdrRow, NS_ERROR_FAILURE);
+  // CreateMsgHdr takes ownership of the hdrRow reference.
+  rv = m_mdbDB->CreateMsgHdr(hdrRow, oid.mOid_Id, result);
+  return (NS_SUCCEEDED(rv)) ? NS_OK : NS_MSG_MESSAGE_NOT_FOUND;
+}
+
+NS_IMETHODIMP nsMsgThread::GetChild(nsMsgKey msgKey, nsIMsgDBHdr** result) {
+  nsresult rv;
+
+  mdb_bool hasOid;
+  mdbOid rowObjectId;
+
+  NS_ENSURE_ARG_POINTER(result);
+  NS_ENSURE_TRUE(m_mdbTable, NS_ERROR_INVALID_POINTER);
+
+  *result = NULL;
+  rowObjectId.mOid_Id = msgKey;
+  rowObjectId.mOid_Scope = m_mdbDB->m_hdrRowScopeToken;
+  rv = m_mdbTable->HasOid(m_mdbDB->GetEnv(), &rowObjectId, &hasOid);
+
+  if (NS_SUCCEEDED(rv) && hasOid && m_mdbDB && m_mdbDB->m_mdbStore) {
+    nsIMdbRow* hdrRow = nullptr;
+    rv = m_mdbDB->m_mdbStore->GetRow(m_mdbDB->GetEnv(), &rowObjectId, &hdrRow);
+    NS_ENSURE_TRUE(NS_SUCCEEDED(rv) && hdrRow, NS_ERROR_FAILURE);
+    rv = m_mdbDB->CreateMsgHdr(hdrRow, msgKey, result);
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgThread::RemoveChildAt(uint32_t aIndex) { return NS_OK; }
+
+nsresult nsMsgThread::RemoveChild(nsMsgKey msgKey) {
+  nsresult rv;
+
+  mdbOid rowObjectId;
+  rowObjectId.mOid_Id = msgKey;
+  rowObjectId.mOid_Scope = m_mdbDB->m_hdrRowScopeToken;
+  rv = m_mdbTable->CutOid(m_mdbDB->GetEnv(), &rowObjectId);
+  // if this thread is empty, remove it from the all threads table.
+  if (m_numChildren == 0 && m_mdbDB->m_mdbAllThreadsTable) {
+    mdbOid rowID;
+    rowID.mOid_Id = m_threadKey;
+    rowID.mOid_Scope = m_mdbDB->m_threadRowScopeToken;
+
+    m_mdbDB->m_mdbAllThreadsTable->CutOid(m_mdbDB->GetEnv(), &rowID);
+  }
+#if 0  // this seems to cause problems
+  if (m_numChildren == 0 && m_metaRow && m_mdbDB)
+    m_metaRow->CutAllColumns(m_mdbDB->GetEnv());
+#endif
+
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgThread::RemoveChildHdr(nsIMsgDBHdr* child,
+                                          nsIDBChangeAnnouncer* announcer) {
+  uint32_t flags;
+  nsMsgKey key;
+  nsMsgKey threadParent;
+
+  NS_ENSURE_ARG_POINTER(child);
+
+  child->GetFlags(&flags);
+  child->GetMessageKey(&key);
+
+  child->GetThreadParent(&threadParent);
+  ReparentChildrenOf(key, threadParent, announcer);
+
+  // if this was the newest msg, clear the newest msg date so we'll recalc.
+  uint32_t date;
+  child->GetDateInSeconds(&date);
+  if (date == m_newestMsgDate) SetNewestMsgDate(0);
+
+  if (!(flags & nsMsgMessageFlags::Read)) ChangeUnreadChildCount(-1);
+  ChangeChildCount(-1);
+  return RemoveChild(key);
+}
+
+nsresult nsMsgThread::ReparentChildrenOf(nsMsgKey oldParent, nsMsgKey newParent,
+                                         nsIDBChangeAnnouncer* announcer) {
+  nsresult rv = NS_OK;
+
+  uint32_t numChildren = 0;
+  GetNumChildren(&numChildren);
+
+  nsCOMPtr<nsIMsgDBHdr> curHdr;
+  if (numChildren > 0) {
+    for (uint32_t childIndex = 0; childIndex < numChildren; childIndex++) {
+      rv = GetChildHdrAt(childIndex, getter_AddRefs(curHdr));
+      if (NS_SUCCEEDED(rv) && curHdr) {
+        nsMsgKey threadParent;
+
+        curHdr->GetThreadParent(&threadParent);
+        if (threadParent == oldParent) {
+          nsMsgKey curKey;
+
+          curHdr->SetThreadParent(newParent);
+          curHdr->GetMessageKey(&curKey);
+          if (announcer)
+            announcer->NotifyParentChangedAll(curKey, oldParent, newParent,
+                                              nullptr);
+          // if the old parent was the root of the thread, then only the first
+          // child gets promoted to root, and other children become children of
+          // the new root.
+          if (newParent == nsMsgKey_None) {
+            SetThreadRootKey(curKey);
+            newParent = curKey;
+          }
+        }
+      }
+    }
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgThread::MarkChildRead(bool bRead) {
+  ChangeUnreadChildCount(bRead ? -1 : 1);
+  return NS_OK;
+}
+
+/**
+ * Helper class for enumerating through the messages in a thread.
+ */
+class nsMsgThreadEnumerator : public nsBaseMsgEnumerator {
+ public:
+  // nsIMsgEnumerator support.
+  NS_IMETHOD GetNext(nsIMsgDBHdr** aItem) override;
+  NS_IMETHOD HasMoreElements(bool* aResult) override;
+
+  // nsMsgThreadEnumerator methods:
+  typedef nsresult (*nsMsgThreadEnumeratorFilter)(nsIMsgDBHdr* hdr,
+                                                  void* closure);
+
+  nsMsgThreadEnumerator(nsMsgThread* thread, nsMsgKey startKey,
+                        nsMsgThreadEnumeratorFilter filter, void* closure);
+  int32_t MsgKeyFirstChildIndex(nsMsgKey inMsgKey);
+
+ protected:
+  ~nsMsgThreadEnumerator() override = default;
+  nsresult Prefetch();
+
+  nsIMdbTableRowCursor* mRowCursor;
+  nsCOMPtr<nsIMsgDBHdr> mResultHdr;
+  RefPtr<nsMsgThread> mThread;
+  nsMsgKey mThreadParentKey;
+  nsMsgKey mFirstMsgKey;
+  int32_t mChildIndex;
+  bool mDone;
+  bool mNeedToPrefetch;
+  nsMsgThreadEnumeratorFilter mFilter;
+  void* mClosure;
+  bool mFoundChildren;
+};
+
+nsMsgThreadEnumerator::nsMsgThreadEnumerator(nsMsgThread* thread,
+                                             nsMsgKey startKey,
+                                             nsMsgThreadEnumeratorFilter filter,
+                                             void* closure)
+    : mRowCursor(nullptr),
+      mDone(false),
+      mFilter(filter),
+      mClosure(closure),
+      mFoundChildren(false) {
+  mThreadParentKey = startKey;
+  mChildIndex = 0;
+  mThread = thread;
+  mNeedToPrefetch = true;
+  mFirstMsgKey = nsMsgKey_None;
+
+  nsresult rv = mThread->GetRootHdr(getter_AddRefs(mResultHdr));
+
+  if (NS_SUCCEEDED(rv) && mResultHdr) mResultHdr->GetMessageKey(&mFirstMsgKey);
+
+  uint32_t numChildren = 0;
+  mThread->GetNumChildren(&numChildren);
+
+  if (mThreadParentKey != nsMsgKey_None) {
+    nsMsgKey msgKey = nsMsgKey_None;
+    for (uint32_t childIndex = 0; childIndex < numChildren; childIndex++) {
+      rv = mThread->GetChildHdrAt(childIndex, getter_AddRefs(mResultHdr));
+      if (NS_SUCCEEDED(rv) && mResultHdr) {
+        mResultHdr->GetMessageKey(&msgKey);
+
+        if (msgKey == startKey) {
+          mChildIndex = MsgKeyFirstChildIndex(msgKey);
+          mDone = (mChildIndex < 0);
+          break;
+        }
+
+        if (mDone) break;
+      } else
+        NS_ASSERTION(false, "couldn't get child from thread");
+    }
+  }
+
+#ifdef DEBUG_bienvenu1
+  nsCOMPtr<nsIMsgDBHdr> child;
+  for (uint32_t childIndex = 0; childIndex < numChildren; childIndex++) {
+    rv = mThread->GetChildHdrAt(childIndex, getter_AddRefs(child));
+    if (NS_SUCCEEDED(rv) && child) {
+      nsMsgKey threadParent;
+      nsMsgKey msgKey;
+      // we're only doing one level of threading, so check if caller is
+      // asking for children of the first message in the thread or not.
+      // if not, we will tell him there are no children.
+      child->GetMessageKey(&msgKey);
+      child->GetThreadParent(&threadParent);
+
+      printf("index = %ld key = %ld parent = %lx\n", childIndex, msgKey,
+             threadParent);
+    }
+  }
+#endif
+}
+
+int32_t nsMsgThreadEnumerator::MsgKeyFirstChildIndex(nsMsgKey inMsgKey) {
+  // if (msgKey != mThreadParentKey)
+  //   mDone = true;
+  // look through rest of thread looking for a child of this message.
+  // If the inMsgKey is the first message in the thread, then all children
+  // without parents are considered to be children of inMsgKey.
+  // Otherwise, only true children qualify.
+
+  int32_t firstChildIndex = -1;
+  uint32_t numChildren = 0;
+  mThread->GetNumChildren(&numChildren);
+
+  // if this is the first message in the thread, just check if there's more than
+  // one message in the thread.
+  // if (inMsgKey == mThread->m_threadRootKey)
+  // return (numChildren > 1) ? 1 : -1;
+
+  for (uint32_t curChildIndex = 0; curChildIndex < numChildren;
+       curChildIndex++) {
+    nsCOMPtr<nsIMsgDBHdr> curHdr;
+    nsresult rv = mThread->GetChildHdrAt(curChildIndex, getter_AddRefs(curHdr));
+    if (NS_SUCCEEDED(rv) && curHdr) {
+      nsMsgKey parentKey;
+
+      curHdr->GetThreadParent(&parentKey);
+      if (parentKey == inMsgKey) {
+        firstChildIndex = curChildIndex;
+        break;
+      }
+    }
+  }
+#ifdef DEBUG_bienvenu1
+  printf("first child index of %ld = %ld\n", inMsgKey, firstChildIndex);
+#endif
+  return firstChildIndex;
+}
+
+NS_IMETHODIMP nsMsgThreadEnumerator::GetNext(nsIMsgDBHdr** aItem) {
+  NS_ENSURE_ARG_POINTER(aItem);
+  nsresult rv;
+
+  if (mNeedToPrefetch) {
+    rv = Prefetch();
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  if (mResultHdr) {
+    NS_ADDREF(*aItem = mResultHdr);
+    mNeedToPrefetch = true;
+  }
+  return NS_OK;
+}
+
+nsresult nsMsgThreadEnumerator::Prefetch() {
+  nsresult rv = NS_OK;  // XXX or should this default to an error?
+  mResultHdr = nullptr;
+  if (mThreadParentKey == nsMsgKey_None) {
+    rv = mThread->GetRootHdr(getter_AddRefs(mResultHdr));
+    NS_ASSERTION(NS_SUCCEEDED(rv) && mResultHdr,
+                 "better be able to get root hdr");
+    mChildIndex = 0;  // since root can be anywhere, set mChildIndex to 0.
+  } else if (!mDone) {
+    uint32_t numChildren = 0;
+    mThread->GetNumChildren(&numChildren);
+
+    while (mChildIndex < (int32_t)numChildren) {
+      rv = mThread->GetChildHdrAt(mChildIndex++, getter_AddRefs(mResultHdr));
+      if (NS_SUCCEEDED(rv) && mResultHdr) {
+        nsMsgKey parentKey;
+        nsMsgKey curKey;
+
+        if (mFilter && NS_FAILED(mFilter(mResultHdr, mClosure))) {
+          mResultHdr = nullptr;
+          continue;
+        }
+
+        mResultHdr->GetThreadParent(&parentKey);
+        mResultHdr->GetMessageKey(&curKey);
+        // if the parent is the same as the msg we're enumerating over,
+        // or the parentKey isn't set, and we're iterating over the top
+        // level message in the thread, then leave mResultHdr set to cur msg.
+        if (parentKey == mThreadParentKey ||
+            (parentKey == nsMsgKey_None && mThreadParentKey == mFirstMsgKey &&
+             curKey != mThreadParentKey))
+          break;
+        mResultHdr = nullptr;
+      } else
+        NS_ASSERTION(false, "better be able to get child");
+    }
+    if (!mResultHdr && mThreadParentKey == mFirstMsgKey && !mFoundChildren &&
+        numChildren > 1)
+      mThread->ReparentMsgsWithInvalidParent(numChildren, mThreadParentKey);
+  }
+  if (!mResultHdr) {
+    mDone = true;
+    return NS_ERROR_FAILURE;
+  }
+  if (NS_FAILED(rv)) {
+    mDone = true;
+    return rv;
+  } else
+    mNeedToPrefetch = false;
+  mFoundChildren = true;
+
+#ifdef DEBUG_bienvenu1
+  nsMsgKey debugMsgKey;
+  mResultHdr->GetMessageKey(&debugMsgKey);
+  printf("next for %ld = %ld\n", mThreadParentKey, debugMsgKey);
+#endif
+
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgThreadEnumerator::HasMoreElements(bool* aResult) {
+  NS_ENSURE_ARG_POINTER(aResult);
+  if (mNeedToPrefetch) Prefetch();
+  *aResult = !mDone;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgThread::EnumerateMessages(nsMsgKey parentKey,
+                                             nsIMsgEnumerator** result) {
+  NS_ADDREF(*result =
+                new nsMsgThreadEnumerator(this, parentKey, nullptr, nullptr));
+  return NS_OK;
+}
+
+nsresult nsMsgThread::ReparentMsgsWithInvalidParent(uint32_t numChildren,
+                                                    nsMsgKey threadParentKey) {
+  nsresult rv = NS_OK;
+  // run through looking for messages that don't have a correct parent,
+  // i.e., a parent that's in the thread!
+  for (uint32_t childIndex = 0; childIndex < numChildren; childIndex++) {
+    nsCOMPtr<nsIMsgDBHdr> curChild;
+    rv = GetChildHdrAt(childIndex, getter_AddRefs(curChild));
+    if (NS_SUCCEEDED(rv) && curChild) {
+      nsMsgKey parentKey;
+      nsCOMPtr<nsIMsgDBHdr> parent;
+
+      curChild->GetThreadParent(&parentKey);
+
+      if (parentKey != nsMsgKey_None) {
+        GetChild(parentKey, getter_AddRefs(parent));
+        if (!parent)
+          curChild->SetThreadParent(threadParentKey);
+        else {
+          nsMsgKey childKey;
+          curChild->GetMessageKey(&childKey);
+          // can't be your own parent; set parent to thread parent,
+          // or make ourselves the root if we are the root.
+          if (childKey == parentKey)
+            curChild->SetThreadParent(
+                m_threadRootKey == childKey ? nsMsgKey_None : m_threadRootKey);
+        }
+      }
+    }
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgThread::GetRootHdr(nsIMsgDBHdr** result) {
+  NS_ENSURE_ARG_POINTER(result);
+
+  *result = nullptr;
+  int32_t resultIndex = -1;
+  nsresult rv = NS_OK;
+
+  if (m_threadRootKey != nsMsgKey_None) {
+    rv = GetChildHdrForKey(m_threadRootKey, result, &resultIndex);
+    if (NS_SUCCEEDED(rv) && *result) {
+      // check that we're really the root key.
+      nsMsgKey parentKey;
+      (*result)->GetThreadParent(&parentKey);
+      if (parentKey == nsMsgKey_None) return rv;
+      // XXX Hack: since GetChildHdrForKey() addref'ed result, we need to
+      // release any unwanted result before continuing.
+      NS_RELEASE(*result);
+    }
+#ifdef DEBUG_David_Bienvenu
+    printf("need to reset thread root key\n");
+#endif
+    nsMsgKey threadParentKey = nsMsgKey_None;
+    uint32_t numChildren = 0;
+    GetNumChildren(&numChildren);
+
+    for (uint32_t childIndex = 0; childIndex < numChildren; childIndex++) {
+      nsCOMPtr<nsIMsgDBHdr> curChild;
+      rv = GetChildHdrAt(childIndex, getter_AddRefs(curChild));
+      if (NS_SUCCEEDED(rv) && curChild) {
+        nsMsgKey parentKey;
+
+        curChild->GetThreadParent(&parentKey);
+        if (parentKey == nsMsgKey_None) {
+          curChild->GetMessageKey(&threadParentKey);
+          if (*result) {
+            NS_WARNING("two top level msgs, not good");
+            continue;
+          }
+          SetThreadRootKey(threadParentKey);
+          curChild.forget(result);
+          ReparentMsgsWithInvalidParent(numChildren, threadParentKey);
+        }
+      }
+    }
+  }
+  if (!*result) {
+    // if we can't get the thread root key, we'll just get the first hdr.
+    // there's a bug where sometimes we weren't resetting the thread root key
+    // when removing the thread root key.
+    rv = GetChildHdrAt(0, result);
+  }
+  if (!*result) return rv;
+  // Check that the thread id of the message is this thread.
+  nsMsgKey threadId = nsMsgKey_None;
+  (void)(*result)->GetThreadId(&threadId);
+  if (threadId != m_threadKey) (*result)->SetThreadId(m_threadKey);
+  return rv;
+}
+
+nsresult nsMsgThread::ChangeChildCount(int32_t delta) {
+  nsresult rv;
+
+  uint32_t childCount = 0;
+  m_mdbDB->RowCellColumnToUInt32(
+      m_metaRow, m_mdbDB->m_threadChildrenColumnToken, childCount);
+
+  NS_WARNING_ASSERTION(childCount != 0 || delta > 0,
+                       "child count gone negative");
+  childCount += delta;
+
+  NS_WARNING_ASSERTION((int32_t)childCount >= 0,
+                       "child count gone to 0 or below");
+  if ((int32_t)childCount < 0)  // force child count to >= 0
+    childCount = 0;
+
+  rv = m_mdbDB->UInt32ToRowCellColumn(
+      m_metaRow, m_mdbDB->m_threadChildrenColumnToken, childCount);
+  m_numChildren = childCount;
+  return rv;
+}
+
+nsresult nsMsgThread::ChangeUnreadChildCount(int32_t delta) {
+  nsresult rv;
+
+  uint32_t childCount = 0;
+  m_mdbDB->RowCellColumnToUInt32(
+      m_metaRow, m_mdbDB->m_threadUnreadChildrenColumnToken, childCount);
+  childCount += delta;
+  if ((int32_t)childCount < 0) {
+#ifdef DEBUG_bienvenu1
+    NS_ASSERTION(false, "negative unread child count");
+#endif
+    childCount = 0;
+  }
+  rv = m_mdbDB->UInt32ToRowCellColumn(
+      m_metaRow, m_mdbDB->m_threadUnreadChildrenColumnToken, childCount);
+  m_numUnreadChildren = childCount;
+  return rv;
+}
+
+nsresult nsMsgThread::SetThreadRootKey(nsMsgKey threadRootKey) {
+  m_threadRootKey = threadRootKey;
+  return m_mdbDB->UInt32ToRowCellColumn(
+      m_metaRow, m_mdbDB->m_threadRootKeyColumnToken, threadRootKey);
+}
+
+nsresult nsMsgThread::GetChildHdrForKey(nsMsgKey desiredKey,
+                                        nsIMsgDBHdr** result,
+                                        int32_t* resultIndex) {
+  NS_ENSURE_ARG_POINTER(result);
+
+  nsresult rv = NS_OK;  // XXX or should this default to an error?
+  uint32_t numChildren = 0;
+  GetNumChildren(&numChildren);
+  uint32_t childIndex;
+  for (childIndex = 0; childIndex < numChildren; childIndex++) {
+    rv = GetChildHdrAt(childIndex, result);
+    if (NS_SUCCEEDED(rv) && *result) {
+      nsMsgKey msgKey;
+      // we're only doing one level of threading, so check if caller is
+      // asking for children of the first message in the thread or not.
+      // if not, we will tell him there are no children.
+      (*result)->GetMessageKey(&msgKey);
+
+      if (msgKey == desiredKey) {
+        nsMsgKey threadKey;
+        (*result)->GetThreadId(&threadKey);
+        if (threadKey != m_threadKey)  // this msg isn't in this thread
+        {
+          NS_WARNING("msg in wrong thread - this shouldn't happen");
+          uint32_t msgSize;
+          (*result)->GetMessageSize(&msgSize);
+          if (msgSize == 0)  // this is a phantom message - let's get rid of it.
+          {
+            RemoveChild(msgKey);
+            rv = NS_ERROR_UNEXPECTED;
+          } else {
+            // otherwise, let's try to figure out which thread
+            // this message really belongs to.
+            nsCOMPtr<nsIMsgThread> threadKeyThread =
+                dont_AddRef(m_mdbDB->GetThreadForThreadId(threadKey));
+            if (threadKeyThread) {
+              nsCOMPtr<nsIMsgDBHdr> otherThreadHdr;
+              threadKeyThread->GetChild(msgKey, getter_AddRefs(otherThreadHdr));
+              if (otherThreadHdr) {
+                // Message is in one thread but has a different thread id.
+                // Remove it from the thread and then rethread it.
+                RemoveChild(msgKey);
+                threadKeyThread->RemoveChildHdr(otherThreadHdr, nullptr);
+                bool newThread;
+                nsMsgHdr* msgHdr = static_cast<nsMsgHdr*>(otherThreadHdr.get());
+                m_mdbDB->ThreadNewHdr(msgHdr, newThread);
+              } else {
+                (*result)->SetThreadId(m_threadKey);
+              }
+            }
+          }
+        }
+        break;
+      }
+      // XXX Hack: since GetChildHdrAt() addref'ed result, we need to
+      // release any unwanted result before continuing in the loop.
+      NS_RELEASE(*result);
+    }
+  }
+  if (resultIndex) *resultIndex = (int32_t)childIndex;
+
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgThread::GetFirstUnreadChild(nsIMsgDBHdr** result) {
+  NS_ENSURE_ARG_POINTER(result);
+
+  uint8_t minLevel = 0xff;
+
+  uint32_t numChildren = 0;
+  GetNumChildren(&numChildren);
+
+  nsCOMPtr<nsIMsgDBHdr> retHdr;
+
+  for (uint32_t childIndex = 0; childIndex < numChildren; childIndex++) {
+    nsCOMPtr<nsIMsgDBHdr> child;
+    nsresult rv = GetChildHdrAt(childIndex, getter_AddRefs(child));
+    if (NS_SUCCEEDED(rv) && child) {
+      nsMsgKey msgKey;
+      child->GetMessageKey(&msgKey);
+
+      bool isRead;
+      rv = m_mdbDB->IsRead(msgKey, &isRead);
+      if (NS_SUCCEEDED(rv) && !isRead) {
+        // this is the root, so it's the best we're going to do.
+        if (msgKey == m_threadRootKey) {
+          retHdr = child;
+          break;
+        }
+        uint8_t level = 0;
+        nsMsgKey parentId;
+        child->GetThreadParent(&parentId);
+        nsCOMPtr<nsIMsgDBHdr> parent;
+        // count number of ancestors - that's our level
+        while (parentId != nsMsgKey_None) {
+          rv = m_mdbDB->GetMsgHdrForKey(parentId, getter_AddRefs(parent));
+          if (parent) {
+            parent->GetThreadParent(&parentId);
+            level++;
+          }
+        }
+        if (level < minLevel) {
+          minLevel = level;
+          retHdr = child;
+        }
+      }
+    }
+  }
+
+  retHdr.forget(result);
+  return (*result) ? NS_OK : NS_ERROR_NULL_POINTER;
+}
+
+NS_IMETHODIMP nsMsgThread::GetNewestMsgDate(uint32_t* aResult) {
+  // if this hasn't been set, figure it out by enumerating the msgs in the
+  // thread.
+  if (!m_newestMsgDate) {
+    nsresult rv;
+    uint32_t numChildren;
+    GetNumChildren(&numChildren);
+    for (uint32_t childIndex = 0; childIndex < numChildren; childIndex++) {
+      nsCOMPtr<nsIMsgDBHdr> child;
+      rv = GetChildHdrAt(childIndex, getter_AddRefs(child));
+      if (NS_SUCCEEDED(rv)) {
+        uint32_t msgDate;
+        child->GetDateInSeconds(&msgDate);
+        if (msgDate > m_newestMsgDate) m_newestMsgDate = msgDate;
+      }
+    }
+  }
+  *aResult = m_newestMsgDate;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgThread::SetNewestMsgDate(uint32_t aNewestMsgDate) {
+  m_newestMsgDate = aNewestMsgDate;
+  return m_mdbDB->UInt32ToRowCellColumn(
+      m_metaRow, m_mdbDB->m_threadNewestMsgDateColumnToken, aNewestMsgDate);
+}
diff --git a/comm/mailnews/db/msgdb/src/nsNewsDatabase.cpp b/comm/mailnews/db/msgdb/src/nsNewsDatabase.cpp
new file mode 100644
index 0000000000..5a5ba19d5e
--- /dev/null
+++ b/comm/mailnews/db/msgdb/src/nsNewsDatabase.cpp
@@ -0,0 +1,307 @@
+/* -*- 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 "msgCore.h"
+#include "nsIMsgDBView.h"
+#include "nsIMsgThread.h"
+#include "nsNewsDatabase.h"
+#include "nsMsgKeySet.h"
+#include "nsMsgMessageFlags.h"
+#include "nsCOMPtr.h"
+#include "prlog.h"
+
+#if defined(DEBUG_sspitzer_) || defined(DEBUG_seth_)
+#  define DEBUG_NEWS_DATABASE 1
+#endif
+
+nsNewsDatabase::nsNewsDatabase() { m_readSet = nullptr; }
+
+nsNewsDatabase::~nsNewsDatabase() {}
+
+NS_IMPL_ADDREF_INHERITED(nsNewsDatabase, nsMsgDatabase)
+NS_IMPL_RELEASE_INHERITED(nsNewsDatabase, nsMsgDatabase)
+
+NS_IMETHODIMP nsNewsDatabase::QueryInterface(REFNSIID aIID,
+                                             void** aInstancePtr) {
+  if (!aInstancePtr) return NS_ERROR_NULL_POINTER;
+  *aInstancePtr = nullptr;
+
+  if (aIID.Equals(NS_GET_IID(nsINewsDatabase))) {
+    *aInstancePtr = static_cast<nsINewsDatabase*>(this);
+  }
+
+  if (*aInstancePtr) {
+    AddRef();
+    return NS_OK;
+  }
+
+  return nsMsgDatabase::QueryInterface(aIID, aInstancePtr);
+}
+
+nsresult nsNewsDatabase::Close(bool forceCommit) {
+  return nsMsgDatabase::Close(forceCommit);
+}
+
+nsresult nsNewsDatabase::ForceClosed() { return nsMsgDatabase::ForceClosed(); }
+
+nsresult nsNewsDatabase::Commit(nsMsgDBCommit commitType) {
+  if (m_dbFolderInfo && m_readSet) {
+    // let's write out our idea of the read set so we can compare it with that
+    // of the .rc file next time we start up.
+    nsCString readSet;
+    m_readSet->Output(getter_Copies(readSet));
+    m_dbFolderInfo->SetCharProperty("readSet", readSet);
+  }
+  return nsMsgDatabase::Commit(commitType);
+}
+
+uint32_t nsNewsDatabase::GetCurVersion() { return kMsgDBVersion; }
+
+NS_IMETHODIMP nsNewsDatabase::IsRead(nsMsgKey key, bool* pRead) {
+  NS_ASSERTION(pRead, "null out param in IsRead");
+  if (!pRead) return NS_ERROR_NULL_POINTER;
+
+  if (!m_readSet) return NS_ERROR_FAILURE;
+
+  *pRead = m_readSet->IsMember(key);
+  return NS_OK;
+}
+
+nsresult nsNewsDatabase::IsHeaderRead(nsIMsgDBHdr* msgHdr, bool* pRead) {
+  nsresult rv;
+  nsMsgKey messageKey;
+
+  if (!msgHdr || !pRead) return NS_ERROR_NULL_POINTER;
+
+  rv = msgHdr->GetMessageKey(&messageKey);
+  if (NS_FAILED(rv)) return rv;
+
+  rv = IsRead(messageKey, pRead);
+  return rv;
+}
+
+// return highest article number we've seen.
+NS_IMETHODIMP nsNewsDatabase::GetHighWaterArticleNum(nsMsgKey* key) {
+  NS_ASSERTION(m_dbFolderInfo, "null db folder info");
+  if (!m_dbFolderInfo) return NS_ERROR_FAILURE;
+  return m_dbFolderInfo->GetHighWater(key);
+}
+
+// return the key of the first article number we know about.
+// Since the iterator iterates in id order, we can just grab the
+// messagekey of the first header it returns.
+// ### dmb
+// This will not deal with the situation where we get holes in
+// the headers we know about. Need to figure out how and when
+// to solve that. This could happen if a transfer is interrupted.
+// Do we need to keep track of known arts permanently?
+NS_IMETHODIMP nsNewsDatabase::GetLowWaterArticleNum(nsMsgKey* key) {
+  nsresult rv;
+
+  nsCOMPtr<nsIMsgEnumerator> hdrs;
+  rv = EnumerateMessages(getter_AddRefs(hdrs));
+  if (NS_FAILED(rv)) return rv;
+
+  nsCOMPtr<nsIMsgDBHdr> first;
+  rv = hdrs->GetNext(getter_AddRefs(first));
+  NS_ASSERTION(NS_SUCCEEDED(rv), "nsMsgDBEnumerator broken");
+  if (NS_FAILED(rv)) return rv;
+
+  return first->GetMessageKey(key);
+}
+
+nsresult nsNewsDatabase::ExpireUpTo(nsMsgKey expireKey) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+nsresult nsNewsDatabase::ExpireRange(nsMsgKey startRange, nsMsgKey endRange) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP nsNewsDatabase::GetReadSet(nsMsgKeySet** pSet) {
+  if (!pSet) return NS_ERROR_NULL_POINTER;
+  *pSet = m_readSet;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNewsDatabase::SetReadSet(nsMsgKeySet* pSet) {
+  m_readSet = pSet;
+
+  if (m_readSet) {
+    // compare this read set with the one in the db folder info.
+    // If not equivalent, sync with this one.
+    nsCString dbReadSet;
+    if (m_dbFolderInfo) m_dbFolderInfo->GetCharProperty("readSet", dbReadSet);
+    nsCString newsrcReadSet;
+    m_readSet->Output(getter_Copies(newsrcReadSet));
+    if (!dbReadSet.Equals(newsrcReadSet)) SyncWithReadSet();
+  }
+  return NS_OK;
+}
+
+bool nsNewsDatabase::SetHdrReadFlag(nsIMsgDBHdr* msgHdr, bool bRead) {
+  nsresult rv;
+  bool isRead;
+  rv = IsHeaderRead(msgHdr, &isRead);
+
+  if (isRead == bRead) {
+    // give the base class a chance to update m_flags.
+    nsMsgDatabase::SetHdrReadFlag(msgHdr, bRead);
+    return false;
+  } else {
+    nsMsgKey messageKey;
+
+    // give the base class a chance to update m_flags.
+    nsMsgDatabase::SetHdrReadFlag(msgHdr, bRead);
+    rv = msgHdr->GetMessageKey(&messageKey);
+    if (NS_FAILED(rv)) return false;
+
+    NS_ASSERTION(m_readSet, "m_readSet is null");
+    if (!m_readSet) return false;
+
+    if (!bRead) {
+#ifdef DEBUG_NEWS_DATABASE
+      printf("remove %d from the set\n", messageKey);
+#endif
+
+      m_readSet->Remove(messageKey);
+
+      rv = NotifyReadChanged(nullptr);
+      if (NS_FAILED(rv)) return false;
+    } else {
+#ifdef DEBUG_NEWS_DATABASE
+      printf("add %d to the set\n", messageKey);
+#endif
+
+      if (m_readSet->Add(messageKey) < 0) return false;
+
+      rv = NotifyReadChanged(nullptr);
+      if (NS_FAILED(rv)) return false;
+    }
+  }
+  return true;
+}
+
+NS_IMETHODIMP nsNewsDatabase::MarkAllRead(nsTArray<nsMsgKey>& aThoseMarked) {
+  nsMsgKey lowWater = nsMsgKey_None, highWater;
+  nsCString knownArts;
+  if (m_dbFolderInfo) {
+    m_dbFolderInfo->GetKnownArtsSet(getter_Copies(knownArts));
+    RefPtr<nsMsgKeySet> knownKeys = nsMsgKeySet::Create(knownArts.get());
+    if (knownKeys) lowWater = knownKeys->GetFirstMember();
+  }
+  if (lowWater == nsMsgKey_None) GetLowWaterArticleNum(&lowWater);
+  GetHighWaterArticleNum(&highWater);
+  if (lowWater > 2) m_readSet->AddRange(1, lowWater - 1);
+  nsresult err = nsMsgDatabase::MarkAllRead(aThoseMarked);
+  if (NS_SUCCEEDED(err) && 1 <= highWater)
+    m_readSet->AddRange(1, highWater);  // mark everything read in newsrc.
+
+  return err;
+}
+
+nsresult nsNewsDatabase::SyncWithReadSet() {
+  // The code below attempts to update the underlying nsMsgDatabase's idea
+  // of read/unread flags to match the read set in the .newsrc file. It should
+  // only be called when they don't match, e.g., we crashed after committing the
+  // db but before writing out the .newsrc
+  nsCOMPtr<nsIMsgEnumerator> hdrs;
+  nsresult rv = EnumerateMessages(getter_AddRefs(hdrs));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool hasMore = false, readInNewsrc, isReadInDB, changed = false;
+  int32_t numMessages = 0, numUnreadMessages = 0;
+
+  // Scan all messages in DB
+  while (NS_SUCCEEDED(rv = hdrs->HasMoreElements(&hasMore)) && hasMore) {
+    nsCOMPtr<nsIMsgDBHdr> header;
+    rv = hdrs->GetNext(getter_AddRefs(header));
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    rv = nsMsgDatabase::IsHeaderRead(header, &isReadInDB);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    nsMsgKey messageKey;
+    header->GetMessageKey(&messageKey);
+    IsRead(messageKey, &readInNewsrc);
+
+    numMessages++;
+    if (!readInNewsrc) numUnreadMessages++;
+
+    // If DB and readSet disagree on Read/Unread, fix DB
+    if (readInNewsrc != isReadInDB) {
+      MarkHdrRead(header, readInNewsrc, nullptr);
+      changed = true;
+    }
+  }
+
+  // Update FolderInfo Counters
+  if (m_dbFolderInfo) {
+    do {
+      int32_t oldMessages, oldUnreadMessages;
+      rv = m_dbFolderInfo->GetNumMessages(&oldMessages);
+      if (NS_FAILED(rv)) break;
+      if (oldMessages != numMessages) {
+        changed = true;
+        m_dbFolderInfo->ChangeNumMessages(numMessages - oldMessages);
+      }
+      rv = m_dbFolderInfo->GetNumUnreadMessages(&oldUnreadMessages);
+      if (NS_FAILED(rv)) break;
+      if (oldUnreadMessages != numUnreadMessages) {
+        changed = true;
+        m_dbFolderInfo->ChangeNumUnreadMessages(numUnreadMessages -
+                                                oldUnreadMessages);
+      }
+    } while (false);
+  }
+
+  if (changed) Commit(nsMsgDBCommitType::kLargeCommit);
+
+  return rv;
+}
+
+nsresult nsNewsDatabase::AdjustExpungedBytesOnDelete(nsIMsgDBHdr* msgHdr) {
+  uint32_t msgFlags;
+  msgHdr->GetFlags(&msgFlags);
+  if (msgFlags & nsMsgMessageFlags::Offline && m_dbFolderInfo) {
+    uint32_t size = 0;
+    (void)msgHdr->GetOfflineMessageSize(&size);
+    return m_dbFolderInfo->ChangeExpungedBytes(size);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNewsDatabase::GetDefaultViewFlags(
+    nsMsgViewFlagsTypeValue* aDefaultViewFlags) {
+  NS_ENSURE_ARG_POINTER(aDefaultViewFlags);
+  GetIntPref("mailnews.default_news_view_flags", aDefaultViewFlags);
+  if (*aDefaultViewFlags < nsMsgViewFlagsType::kNone ||
+      *aDefaultViewFlags >
+          (nsMsgViewFlagsType::kThreadedDisplay |
+           nsMsgViewFlagsType::kShowIgnored | nsMsgViewFlagsType::kUnreadOnly |
+           nsMsgViewFlagsType::kExpandAll | nsMsgViewFlagsType::kGroupBySort))
+    *aDefaultViewFlags = nsMsgViewFlagsType::kThreadedDisplay;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNewsDatabase::GetDefaultSortType(nsMsgViewSortTypeValue* aDefaultSortType) {
+  NS_ENSURE_ARG_POINTER(aDefaultSortType);
+  GetIntPref("mailnews.default_news_sort_type", aDefaultSortType);
+  if (*aDefaultSortType < nsMsgViewSortType::byDate ||
+      *aDefaultSortType > nsMsgViewSortType::byAccount)
+    *aDefaultSortType = nsMsgViewSortType::byThread;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNewsDatabase::GetDefaultSortOrder(
+    nsMsgViewSortOrderValue* aDefaultSortOrder) {
+  NS_ENSURE_ARG_POINTER(aDefaultSortOrder);
+  GetIntPref("mailnews.default_news_sort_order", aDefaultSortOrder);
+  if (*aDefaultSortOrder != nsMsgViewSortOrder::descending)
+    *aDefaultSortOrder = nsMsgViewSortOrder::ascending;
+  return NS_OK;
+}
diff --git a/comm/mailnews/db/msgdb/test/moz.build b/comm/mailnews/db/msgdb/test/moz.build
new file mode 100644
index 0000000000..6b37fdbe09
--- /dev/null
+++ b/comm/mailnews/db/msgdb/test/moz.build
@@ -0,0 +1,6 @@
+# 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.ini"]
diff --git a/comm/mailnews/db/msgdb/test/unit/head_maildb.js b/comm/mailnews/db/msgdb/test/unit/head_maildb.js
new file mode 100644
index 0000000000..5b52dbb304
--- /dev/null
+++ b/comm/mailnews/db/msgdb/test/unit/head_maildb.js
@@ -0,0 +1,21 @@
+var { MailServices } = ChromeUtils.import(
+  "resource:///modules/MailServices.jsm"
+);
+var { XPCOMUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/XPCOMUtils.sys.mjs"
+);
+var { mailTestUtils } = ChromeUtils.import(
+  "resource://testing-common/mailnews/MailTestUtils.jsm"
+);
+var { localAccountUtils } = ChromeUtils.import(
+  "resource://testing-common/mailnews/LocalAccountUtils.jsm"
+);
+
+var CC = Components.Constructor;
+
+// Ensure the profile directory is set up
+do_get_profile();
+
+registerCleanupFunction(function () {
+  load("../../../../../mailnews/resources/mailShutdown.js");
+});
diff --git a/comm/mailnews/db/msgdb/test/unit/test_enumerator_cleanup.js b/comm/mailnews/db/msgdb/test/unit/test_enumerator_cleanup.js
new file mode 100644
index 0000000000..dfb5aa5285
--- /dev/null
+++ b/comm/mailnews/db/msgdb/test/unit/test_enumerator_cleanup.js
@@ -0,0 +1,56 @@
+/*
+ * Test nsMsgDatabase's cleanup of nsMsgDBEnumerators
+ */
+
+var { MailServices } = ChromeUtils.import(
+  "resource:///modules/MailServices.jsm"
+);
+
+var anyOldMessage = do_get_file("../../../../data/bugmail1");
+
+/**
+ * Test closing a db with an outstanding enumerator.
+ */
+function test_enumerator_cleanup() {
+  let db = localAccountUtils.inboxFolder.msgDatabase;
+  let enumerator = db.enumerateMessages();
+  Cc["@mozilla.org/msgDatabase/msgDBService;1"]
+    .getService(Ci.nsIMsgDBService)
+    .forceFolderDBClosed(localAccountUtils.inboxFolder);
+  localAccountUtils.inboxFolder.msgDatabase = null;
+  db = null;
+  gc();
+  [...enumerator];
+  do_test_finished();
+}
+
+/*
+ * This infrastructure down here exists just to get
+ *  test_references_header_parsing its message header.
+ */
+
+function run_test() {
+  localAccountUtils.loadLocalMailAccount();
+  do_test_pending();
+  MailServices.copy.copyFileMessage(
+    anyOldMessage,
+    localAccountUtils.inboxFolder,
+    null,
+    false,
+    0,
+    "",
+    messageHeaderGetterListener,
+    null
+  );
+  return true;
+}
+
+var messageHeaderGetterListener = {
+  OnStartCopy() {},
+  OnProgress(aProgress, aProgressMax) {},
+  GetMessageId(aMessageId) {},
+  SetMessageKey(aKey) {},
+  OnStopCopy(aStatus) {
+    do_timeout(0, test_enumerator_cleanup);
+  },
+};
diff --git a/comm/mailnews/db/msgdb/test/unit/test_filter_enumerator.js b/comm/mailnews/db/msgdb/test/unit/test_filter_enumerator.js
new file mode 100644
index 0000000000..914b5afd29
--- /dev/null
+++ b/comm/mailnews/db/msgdb/test/unit/test_filter_enumerator.js
@@ -0,0 +1,100 @@
+/* import-globals-from ../../../../test/resources/MessageGenerator.jsm */
+load("../../../../resources/MessageGenerator.jsm");
+
+var gMessages = [];
+
+const kSetCount = 13;
+const kNumExpectedMatches = 10;
+
+function setupGlobals() {
+  localAccountUtils.loadLocalMailAccount();
+  // Create a message generator
+  let messageGenerator = new MessageGenerator();
+  let localInbox = localAccountUtils.inboxFolder.QueryInterface(
+    Ci.nsIMsgLocalMailFolder
+  );
+
+  for (let i = 0; i < kSetCount; i++) {
+    let message = messageGenerator.makeMessage();
+    gMessages.push(message);
+    localInbox.addMessage(message.toMboxString());
+  }
+}
+
+function run_test() {
+  setupGlobals();
+  do_test_pending();
+  let inboxDB = localAccountUtils.inboxFolder.msgDatabase;
+
+  // give messages 1,3,5 gloda-ids. These won't end up in our search hits.
+  let msgHdr1 = inboxDB.getMsgHdrForMessageID(gMessages[0].messageId);
+  msgHdr1.setUint32Property("gloda-id", 11111);
+  let msgHdr3 = inboxDB.getMsgHdrForMessageID(gMessages[2].messageId);
+  msgHdr3.setUint32Property("gloda-id", 33333);
+  let msgHdr5 = inboxDB.getMsgHdrForMessageID(gMessages[4].messageId);
+  msgHdr5.setUint32Property("gloda-id", 5555);
+  // set up a search term array that will give us the array of messages
+  // that gloda should index, as defined by this function:
+  let searchSession = Cc[
+    "@mozilla.org/messenger/searchSession;1"
+  ].createInstance(Ci.nsIMsgSearchSession);
+  let searchTerms = [];
+
+  searchSession.addScopeTerm(
+    Ci.nsMsgSearchScope.offlineMail,
+    localAccountUtils.inboxFolder
+  );
+  let searchTerm = searchSession.createTerm();
+
+  // Create the following search term:
+  // (folderFlag & Mail && folderFlag != ImapBox) &&
+  //    msg property.gloda-id isEmpty
+
+  searchTerm.beginsGrouping = true;
+  searchTerm.booleanAnd = true;
+  searchTerm.attrib = Ci.nsMsgSearchAttrib.FolderFlag;
+  searchTerm.op = Ci.nsMsgSearchOp.Is;
+  let value = searchTerm.value;
+  value.status = Ci.nsMsgFolderFlags.Mail;
+  value.attrib = Ci.nsMsgSearchAttrib.FolderFlag;
+  searchTerm.value = value;
+  searchTerms.push(searchTerm);
+
+  searchTerm = searchSession.createTerm();
+  searchTerm.booleanAnd = true;
+  searchTerm.attrib = Ci.nsMsgSearchAttrib.FolderFlag;
+  searchTerm.op = Ci.nsMsgSearchOp.Isnt;
+  value = searchTerm.value;
+  value.status = Ci.nsMsgFolderFlags.ImapBox;
+  value.attrib = Ci.nsMsgSearchAttrib.FolderFlag;
+  searchTerm.value = value;
+  searchTerm.endsGrouping = true;
+  searchTerms.push(searchTerm);
+
+  searchTerm = searchSession.createTerm();
+  searchTerm.booleanAnd = true;
+  searchTerm.attrib = Ci.nsMsgSearchAttrib.HdrProperty;
+  searchTerm.hdrProperty = "gloda-id";
+  searchTerm.op = Ci.nsMsgSearchOp.IsEmpty;
+  value = searchTerm.value;
+  value.str = "gloda-id";
+  value.attrib = Ci.nsMsgSearchAttrib.HdrProperty;
+  searchTerm.value = value;
+  searchTerms.push(searchTerm);
+
+  let msgEnumerator = inboxDB.getFilterEnumerator(searchTerms);
+  let matchingHdrs = [...msgEnumerator];
+  Assert.equal(kNumExpectedMatches, matchingHdrs.length);
+  Assert.equal(matchingHdrs[0].messageId, gMessages[1].messageId);
+  Assert.equal(matchingHdrs[1].messageId, gMessages[3].messageId);
+
+  // try it backwards, with roller skates:
+  msgEnumerator = inboxDB.getFilterEnumerator(searchTerms, true);
+  matchingHdrs = [...msgEnumerator];
+  Assert.equal(kNumExpectedMatches, matchingHdrs.length);
+  Assert.equal(matchingHdrs[0].messageId, gMessages[12].messageId);
+  Assert.equal(matchingHdrs[1].messageId, gMessages[11].messageId);
+  Assert.equal(matchingHdrs[9].messageId, gMessages[1].messageId);
+
+  do_test_finished();
+}
diff --git a/comm/mailnews/db/msgdb/test/unit/test_mailTelemetry.js b/comm/mailnews/db/msgdb/test/unit/test_mailTelemetry.js
new file mode 100644
index 0000000000..c0bc034bad
--- /dev/null
+++ b/comm/mailnews/db/msgdb/test/unit/test_mailTelemetry.js
@@ -0,0 +1,38 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Test telemetry related to mails read.
+ */
+
+let { TelemetryTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/TelemetryTestUtils.sys.mjs"
+);
+
+/**
+ * Check that we're counting mails read.
+ */
+add_task(async function test_mails_read() {
+  Services.telemetry.clearScalars();
+
+  localAccountUtils.loadLocalMailAccount();
+
+  const NUM_MAILS = 5;
+  let headers =
+    "from: alice@t1.example.com\r\n" +
+    "to: bob@t2.example.net\r\n" +
+    "return-path: alice@t1.example.com\r\n" +
+    "Disposition-Notification-To: alice@t1.example.com\r\n";
+  for (let i = 0; i < NUM_MAILS; i++) {
+    localAccountUtils.inboxFolder.addMessage(
+      "From \r\n" + headers + "\r\nhello\r\n"
+    );
+  }
+  localAccountUtils.inboxFolder.markAllMessagesRead(null);
+  const scalars = TelemetryTestUtils.getProcessScalars("parent");
+  Assert.equal(
+    scalars["tb.mails.read"],
+    NUM_MAILS,
+    "Count of mails read must be correct."
+  );
+});
diff --git a/comm/mailnews/db/msgdb/test/unit/test_maildb.js b/comm/mailnews/db/msgdb/test/unit/test_maildb.js
new file mode 100644
index 0000000000..9b6bca9303
--- /dev/null
+++ b/comm/mailnews/db/msgdb/test/unit/test_maildb.js
@@ -0,0 +1,67 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/*
+ * Test suite for msg database functions.
+ */
+
+/* import-globals-from ../../../../test/resources/MessageGenerator.jsm */
+load("../../../../resources/MessageGenerator.jsm");
+
+var dbService;
+var gTestFolder;
+var gCurTestNum = 0;
+var kNumTestMessages = 10;
+
+var gTestArray = [
+  function test_db_open() {
+    dbService = Cc["@mozilla.org/msgDatabase/msgDBService;1"].getService(
+      Ci.nsIMsgDBService
+    );
+    // Get the root folder
+    let root = localAccountUtils.incomingServer.rootFolder;
+    root.createSubfolder("dbTest", null);
+    gTestFolder = root.getChildNamed("dbTest");
+    let db = dbService.openFolderDB(gTestFolder, true);
+    Assert.notEqual(db, null);
+    db.dBFolderInfo.highWater = 10;
+    db.close(true);
+    db = dbService.openFolderDB(gTestFolder, true);
+    Assert.notEqual(db, null);
+    Assert.equal(db.dBFolderInfo.highWater, 10);
+    db.dBFolderInfo.onKeyAdded(15);
+    Assert.equal(db.dBFolderInfo.highWater, 15);
+    db.close(true);
+    db.forceClosed();
+    db = null;
+    doTest(++gCurTestNum);
+  },
+];
+
+function doTest(test) {
+  if (test <= gTestArray.length) {
+    dump("Doing test " + test + "\n");
+    gCurTestNum = test;
+
+    var testFn = gTestArray[test - 1];
+    // Set a limit of 10 seconds; if the notifications haven't arrived by then there's a problem.
+    do_timeout(10000, function () {
+      if (gCurTestNum == test) {
+        do_throw(
+          "Notifications not received in 10000 ms for operation " + testFn.name
+        );
+      }
+    });
+    try {
+      testFn();
+    } catch (ex) {
+      do_throw(ex);
+    }
+  } else {
+    do_test_finished(); // for the one in run_test()
+  }
+}
+
+function run_test() {
+  localAccountUtils.loadLocalMailAccount();
+  do_test_pending();
+  doTest(1);
+}
diff --git a/comm/mailnews/db/msgdb/test/unit/test_propertyEnumerator.js b/comm/mailnews/db/msgdb/test/unit/test_propertyEnumerator.js
new file mode 100644
index 0000000000..57fb2605bd
--- /dev/null
+++ b/comm/mailnews/db/msgdb/test/unit/test_propertyEnumerator.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/. */
+
+// tests properties in nsIMsgDBHdr;
+
+var { MailServices } = ChromeUtils.import(
+  "resource:///modules/MailServices.jsm"
+);
+
+var gHdr;
+
+function run_test() {
+  localAccountUtils.loadLocalMailAccount();
+  // Get a message into the local filestore.
+  // Function continue_test() continues the testing after the copy.
+  var bugmail1 = do_get_file("../../../../data/bugmail1");
+  do_test_pending();
+  MailServices.copy.copyFileMessage(
+    bugmail1,
+    localAccountUtils.inboxFolder,
+    null,
+    false,
+    0,
+    "",
+    copyListener,
+    null
+  );
+}
+
+var copyListener = {
+  OnStartCopy() {},
+  OnProgress(aProgress, aProgressMax) {},
+  SetMessageKey(aKey) {
+    gHdr = localAccountUtils.inboxFolder.GetMessageHeader(aKey);
+  },
+  SetMessageId(aMessageId) {},
+  OnStopCopy(aStatus) {
+    continue_test();
+  },
+};
+
+function continue_test() {
+  // test some of the default properties
+  let properties = gHdr.properties;
+  Assert.ok(properties.includes("flags"));
+  Assert.ok(properties.includes("size"));
+  // this will be added in the next section, but does not exist yet
+  Assert.ok(!properties.includes("iamnew"));
+
+  // add a new property, and make sure that it appears
+  gHdr.setStringProperty("iamnew", "somevalue");
+
+  properties = [];
+  for (let property of gHdr.properties) {
+    // dump("\nProperty 2 is " + property);
+    properties.push(property);
+  }
+  Assert.ok(properties.includes("flags"));
+  Assert.ok(properties.includes("size"));
+  Assert.ok(properties.includes("iamnew"));
+  Assert.ok(!properties.includes("idonotexist"));
+
+  gHdr = null;
+  do_test_finished();
+}
diff --git a/comm/mailnews/db/msgdb/test/unit/test_references_parsing.js b/comm/mailnews/db/msgdb/test/unit/test_references_parsing.js
new file mode 100644
index 0000000000..fdfa76dd6d
--- /dev/null
+++ b/comm/mailnews/db/msgdb/test/unit/test_references_parsing.js
@@ -0,0 +1,124 @@
+/*
+ * Test nsMsgHdr's In-Reply-To/References parsing logic.
+ */
+
+var { MailServices } = ChromeUtils.import(
+  "resource:///modules/MailServices.jsm"
+);
+
+var anyOldMessage = do_get_file("../../../../data/bugmail1");
+
+var refsAndResults = [
+  // an empty string is not a reference.
+  ["", []],
+  // super valid things
+  ["<abc@def>", ["abc@def"]],
+  [
+    "<up@down> <left@right> <ying@yang>",
+    ["up@down", "left@right", "ying@yang"],
+  ],
+  // whitespace type things
+  ["    ", []],
+  ["   <left@space>", ["left@space"]],
+  ["<space@right>   ", ["space@right"]],
+  ["   <space@space>   ", ["space@space"]],
+  ["\t<tab@tab>\t", ["tab@tab"]],
+  ["<a@b>\n\t<tab@newline.n>", ["a@b", "tab@newline.n"]],
+  ["<a@b>\r\t<tab@newline.r>", ["a@b", "tab@newline.r"]],
+  ["<a@b>\n\t<tab@newline.nr>", ["a@b", "tab@newline.nr"]],
+  [
+    "<a@1>\n<a@2> <a@3>\t <a@4>\n  <a@5>\r\t<a@6>\r\n <a@7>\r\n\t ",
+    ["a@1", "a@2", "a@3", "a@4", "a@5", "a@6", "a@7"],
+  ],
+  // be backwards compatible with old-school things that make some sense
+  ["i am a stupid message-id", ["i am a stupid message-id"]],
+  ["  those were spaces!", ["those were spaces!"]],
+  // be backwards compatible with things that make no sense
+  ["  seriously\n who does this?", ["seriously\n who does this?"]],
+  // handle things we used to be stupid about
+  ["<z@1a> was an awesome message!", ["z@1a"]],
+  ["   <z@1b> was an awesomer message!", ["z@1b"]],
+  ["I can't get enough of <z@2a>", ["z@2a"]],
+  ["   nor of I can enough get <z@2b>   ", ["z@2b"]],
+  ["let's talk about <z@3a> shall we", ["z@3a"]],
+  ["and then let us speak of <z@3b> and its\n many points", ["z@3b"]],
+  // be backwards compatible with things that just seem malicious
+  [" 4 < 5", ["4 < 5"]],
+  [" 6 > 3", ["6 > 3"]],
+  ["  look ma!\n newlines!", ["look ma!\n newlines!"]],
+];
+
+/**
+ * Parse the references in refsAndResults and ensure their references match
+ *  the corresponding results.
+ *
+ * @param {nsIMsgDBHdr} aMsgHdr - A message header that you don't mind if we
+ *   mess with.
+ */
+function test_references_header_parsing(aMsgHdr) {
+  var iCase, iResult, refString, results;
+  for (iCase = 0; iCase < refsAndResults.length; iCase++) {
+    refString = refsAndResults[iCase][0];
+    results = refsAndResults[iCase][1];
+
+    dump("Setting references to: '" + refString + "'\n");
+    aMsgHdr.setReferences(refString);
+    if (aMsgHdr.numReferences != results.length) {
+      dump("Length mismatch! Was expecting:\n");
+      for (iResult = 0; iResult < results.length; iResult++) {
+        dump("'" + results[iResult] + "'\n");
+      }
+
+      dump("Got:\n");
+
+      for (iResult = 0; iResult < aMsgHdr.numReferences; iResult++) {
+        dump("'" + aMsgHdr.getStringReference(iResult) + "'\n");
+      }
+
+      Assert.equal(aMsgHdr.numReferences, results.length);
+    }
+
+    for (iResult = 0; iResult < results.length; iResult++) {
+      Assert.equal(aMsgHdr.getStringReference(iResult), results[iResult]);
+    }
+  }
+
+  do_test_finished();
+}
+
+/*
+ * This infrastructure down here exists just to get
+ *  test_references_header_parsing its message header.
+ */
+
+function run_test() {
+  localAccountUtils.loadLocalMailAccount();
+  do_test_pending();
+  MailServices.copy.copyFileMessage(
+    anyOldMessage,
+    localAccountUtils.inboxFolder,
+    null,
+    false,
+    0,
+    "",
+    messageHeaderGetterListener,
+    null
+  );
+  return true;
+}
+
+var messageHeaderGetterListener = {
+  msgKey: null,
+
+  OnStartCopy() {},
+  OnProgress(aProgress, aProgressMax) {},
+  GetMessageId(aMessageId) {},
+  SetMessageKey(aKey) {
+    this.msgKey = aKey;
+  },
+  OnStopCopy(aStatus) {
+    test_references_header_parsing(
+      localAccountUtils.inboxFolder.GetMessageHeader(this.msgKey)
+    );
+  },
+};
diff --git a/comm/mailnews/db/msgdb/test/unit/xpcshell.ini b/comm/mailnews/db/msgdb/test/unit/xpcshell.ini
new file mode 100644
index 0000000000..d32c984408
--- /dev/null
+++ b/comm/mailnews/db/msgdb/test/unit/xpcshell.ini
@@ -0,0 +1,10 @@
+[DEFAULT]
+head = head_maildb.js
+tail =
+
+[test_enumerator_cleanup.js]
+[test_filter_enumerator.js]
+[test_maildb.js]
+[test_mailTelemetry.js]
+[test_propertyEnumerator.js]
+[test_references_parsing.js]