Add m-esr52 at 52.6.0

1 files changed, 1536 insertions, 0 deletions

diff --git a/toolkit/components/places/Bookmarks.jsm b/toolkit/components/places/Bookmarks.jsm
new file mode 100644
index 0000000000..835b4fc620
--- /dev/null
+++ b/toolkit/components/places/Bookmarks.jsm
@@ -0,0 +1,1536 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+/**
+ * This module provides an asynchronous API for managing bookmarks.
+ *
+ * Bookmarks are organized in a tree structure, and include URLs, folders and
+ * separators.  Multiple bookmarks for the same URL are allowed.
+ *
+ * Note that if you are handling bookmarks operations in the UI, you should
+ * not use this API directly, but rather use PlacesTransactions.jsm, so that
+ * any operation is undo/redo-able.
+ *
+ * Each bookmark-item is represented by an object having the following
+ * properties:
+ *
+ *  - guid (string)
+ *      The globally unique identifier of the item.
+ *  - parentGuid (string)
+ *      The globally unique identifier of the folder containing the item.
+ *      This will be an empty string for the Places root folder.
+ *  - index (number)
+ *      The 0-based position of the item in the parent folder.
+ *  - dateAdded (Date)
+ *      The time at which the item was added.
+ *  - lastModified (Date)
+ *      The time at which the item was last modified.
+ *  - type (number)
+ *      The item's type, either TYPE_BOOKMARK, TYPE_FOLDER or TYPE_SEPARATOR.
+ *
+ *  The following properties are only valid for URLs or folders.
+ *
+ *  - title (string)
+ *      The item's title, if any.  Empty titles and null titles are considered
+ *      the same, and the property is unset on retrieval in such a case.
+ *      Titles longer than DB_TITLE_LENGTH_MAX will be truncated.
+ *
+ *  The following properties are only valid for URLs:
+ *
+ *  - url (URL, href or nsIURI)
+ *      The item's URL.  Note that while input objects can contains either
+ *      an URL object, an href string, or an nsIURI, output objects will always
+ *      contain an URL object.
+ *      An URL cannot be longer than DB_URL_LENGTH_MAX, methods will throw if a
+ *      longer value is provided.
+ *
+ * Each successful operation notifies through the nsINavBookmarksObserver
+ * interface.  To listen to such notifications you must register using
+ * nsINavBookmarksService addObserver and removeObserver methods.
+ * Note that bookmark addition or order changes won't notify onItemMoved for
+ * items that have their indexes changed.
+ * Similarly, lastModified changes not done explicitly (like changing another
+ * property) won't fire an onItemChanged notification for the lastModified
+ * property.
+ * @see nsINavBookmarkObserver
+ */
+
+this.EXPORTED_SYMBOLS = [ "Bookmarks" ];
+
+const { classes: Cc, interfaces: Ci, results: Cr, utils: Cu } = Components;
+
+Cu.importGlobalProperties(["URL"]);
+
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "Services",
+                                  "resource://gre/modules/Services.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "NetUtil",
+                                  "resource://gre/modules/NetUtil.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "Promise",
+                                  "resource://gre/modules/Promise.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "Task",
+                                  "resource://gre/modules/Task.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "Sqlite",
+                                  "resource://gre/modules/Sqlite.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "PlacesUtils",
+                                  "resource://gre/modules/PlacesUtils.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "PlacesSyncUtils",
+                                  "resource://gre/modules/PlacesSyncUtils.jsm");
+
+const MATCH_ANYWHERE_UNMODIFIED = Ci.mozIPlacesAutoComplete.MATCH_ANYWHERE_UNMODIFIED;
+const BEHAVIOR_BOOKMARK = Ci.mozIPlacesAutoComplete.BEHAVIOR_BOOKMARK;
+
+var Bookmarks = Object.freeze({
+  /**
+   * Item's type constants.
+   * These should stay consistent with nsINavBookmarksService.idl
+   */
+  TYPE_BOOKMARK: 1,
+  TYPE_FOLDER: 2,
+  TYPE_SEPARATOR: 3,
+
+  /**
+   * Default index used to append a bookmark-item at the end of a folder.
+   * This should stay consistent with nsINavBookmarksService.idl
+   */
+  DEFAULT_INDEX: -1,
+
+  /**
+   * Bookmark change source constants, passed as optional properties and
+   * forwarded to observers. See nsINavBookmarksService.idl for an explanation.
+   */
+  SOURCES: {
+    DEFAULT: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+    SYNC: Ci.nsINavBookmarksService.SOURCE_SYNC,
+    IMPORT: Ci.nsINavBookmarksService.SOURCE_IMPORT,
+    IMPORT_REPLACE: Ci.nsINavBookmarksService.SOURCE_IMPORT_REPLACE,
+  },
+
+  /**
+   * Special GUIDs associated with bookmark roots.
+   * It's guaranteed that the roots will always have these guids.
+   */
+
+   rootGuid:    "root________",
+   menuGuid:    "menu________",
+   toolbarGuid: "toolbar_____",
+   unfiledGuid: "unfiled_____",
+   mobileGuid:  "mobile______",
+
+   // With bug 424160, tags will stop being bookmarks, thus this root will
+   // be removed.  Do not rely on this, rather use the tagging service API.
+   tagsGuid:    "tags________",
+
+  /**
+   * Inserts a bookmark-item into the bookmarks tree.
+   *
+   * For creating a bookmark, the following set of properties is required:
+   *  - type
+   *  - parentGuid
+   *  - url, only for bookmarked URLs
+   *
+   * If an index is not specified, it defaults to appending.
+   * It's also possible to pass a non-existent GUID to force creation of an
+   * item with the given GUID, but unless you have a very sound reason, such as
+   * an undo manager implementation or synchronization, don't do that.
+   *
+   * Note that any known properties that don't apply to the specific item type
+   * cause an exception.
+   *
+   * @param info
+   *        object representing a bookmark-item.
+   *
+   * @return {Promise} resolved when the creation is complete.
+   * @resolves to an object representing the created bookmark.
+   * @rejects if it's not possible to create the requested bookmark.
+   * @throws if the arguments are invalid.
+   */
+  insert(info) {
+    // Ensure to use the same date for dateAdded and lastModified, even if
+    // dateAdded may be imposed by the caller.
+    let time = (info && info.dateAdded) || new Date();
+    let insertInfo = validateBookmarkObject(info,
+      { type: { defaultValue: this.TYPE_BOOKMARK }
+      , index: { defaultValue: this.DEFAULT_INDEX }
+      , url: { requiredIf: b => b.type == this.TYPE_BOOKMARK
+             , validIf: b => b.type == this.TYPE_BOOKMARK }
+      , parentGuid: { required: true }
+      , title: { validIf: b => [ this.TYPE_BOOKMARK
+                               , this.TYPE_FOLDER ].includes(b.type) }
+      , dateAdded: { defaultValue: time
+                   , validIf: b => !b.lastModified ||
+                                    b.dateAdded <= b.lastModified }
+      , lastModified: { defaultValue: time,
+                        validIf: b => (!b.dateAdded && b.lastModified >= time) ||
+                                      (b.dateAdded && b.lastModified >= b.dateAdded) }
+      , source: { defaultValue: this.SOURCES.DEFAULT }
+      });
+
+    return Task.spawn(function* () {
+      // Ensure the parent exists.
+      let parent = yield fetchBookmark({ guid: insertInfo.parentGuid });
+      if (!parent)
+        throw new Error("parentGuid must be valid");
+
+      // Set index in the appending case.
+      if (insertInfo.index == this.DEFAULT_INDEX ||
+          insertInfo.index > parent._childCount) {
+        insertInfo.index = parent._childCount;
+      }
+
+      let item = yield insertBookmark(insertInfo, parent);
+
+      // Notify onItemAdded to listeners.
+      let observers = PlacesUtils.bookmarks.getObservers();
+      // We need the itemId to notify, though once the switch to guids is
+      // complete we may stop using it.
+      let uri = item.hasOwnProperty("url") ? PlacesUtils.toURI(item.url) : null;
+      let itemId = yield PlacesUtils.promiseItemId(item.guid);
+
+      // Pass tagging information for the observers to skip over these notifications when needed.
+      let isTagging = parent._parentId == PlacesUtils.tagsFolderId;
+      let isTagsFolder = parent._id == PlacesUtils.tagsFolderId;
+      notify(observers, "onItemAdded", [ itemId, parent._id, item.index,
+                                         item.type, uri, item.title || null,
+                                         PlacesUtils.toPRTime(item.dateAdded), item.guid,
+                                         item.parentGuid, item.source ],
+                                       { isTagging: isTagging || isTagsFolder });
+
+      // If it's a tag, notify OnItemChanged to all bookmarks for this URL.
+      if (isTagging) {
+        for (let entry of (yield fetchBookmarksByURL(item))) {
+          notify(observers, "onItemChanged", [ entry._id, "tags", false, "",
+                                               PlacesUtils.toPRTime(entry.lastModified),
+                                               entry.type, entry._parentId,
+                                               entry.guid, entry.parentGuid,
+                                               "", item.source ]);
+        }
+      }
+
+      // Remove non-enumerable properties.
+      delete item.source;
+      return Object.assign({}, item);
+    }.bind(this));
+  },
+
+  /**
+   * Updates a bookmark-item.
+   *
+   * Only set the properties which should be changed (undefined properties
+   * won't be taken into account).
+   * Moreover, the item's type or dateAdded cannot be changed, since they are
+   * immutable after creation.  Trying to change them will reject.
+   *
+   * Note that any known properties that don't apply to the specific item type
+   * cause an exception.
+   *
+   * @param info
+   *        object representing a bookmark-item, as defined above.
+   *
+   * @return {Promise} resolved when the update is complete.
+   * @resolves to an object representing the updated bookmark.
+   * @rejects if it's not possible to update the given bookmark.
+   * @throws if the arguments are invalid.
+   */
+  update(info) {
+    // The info object is first validated here to ensure it's consistent, then
+    // it's compared to the existing item to remove any properties that don't
+    // need to be updated.
+    let updateInfo = validateBookmarkObject(info,
+      { guid: { required: true }
+      , index: { requiredIf: b => b.hasOwnProperty("parentGuid")
+               , validIf: b => b.index >= 0 || b.index == this.DEFAULT_INDEX }
+      , source: { defaultValue: this.SOURCES.DEFAULT }
+      });
+
+    // There should be at last one more property in addition to guid and source.
+    if (Object.keys(updateInfo).length < 3)
+      throw new Error("Not enough properties to update");
+
+    return Task.spawn(function* () {
+      // Ensure the item exists.
+      let item = yield fetchBookmark(updateInfo);
+      if (!item)
+        throw new Error("No bookmarks found for the provided GUID");
+      if (updateInfo.hasOwnProperty("type") && updateInfo.type != item.type)
+        throw new Error("The bookmark type cannot be changed");
+      if (updateInfo.hasOwnProperty("dateAdded") &&
+          updateInfo.dateAdded.getTime() != item.dateAdded.getTime())
+        throw new Error("The bookmark dateAdded cannot be changed");
+
+      // Remove any property that will stay the same.
+      removeSameValueProperties(updateInfo, item);
+      // Check if anything should still be updated.
+      if (Object.keys(updateInfo).length < 3) {
+        // Remove non-enumerable properties.
+        return Object.assign({}, item);
+      }
+
+      updateInfo = validateBookmarkObject(updateInfo,
+        { url: { validIf: () => item.type == this.TYPE_BOOKMARK }
+        , title: { validIf: () => [ this.TYPE_BOOKMARK
+                                  , this.TYPE_FOLDER ].includes(item.type) }
+        , lastModified: { defaultValue: new Date()
+                        , validIf: b => b.lastModified >= item.dateAdded }
+        });
+
+      return PlacesUtils.withConnectionWrapper("Bookmarks.jsm: update",
+        Task.async(function*(db) {
+        let parent;
+        if (updateInfo.hasOwnProperty("parentGuid")) {
+          if (item.type == this.TYPE_FOLDER) {
+            // Make sure we are not moving a folder into itself or one of its
+            // descendants.
+            let rows = yield db.executeCached(
+              `WITH RECURSIVE
+               descendants(did) AS (
+                 VALUES(:id)
+                 UNION ALL
+                 SELECT id FROM moz_bookmarks
+                 JOIN descendants ON parent = did
+                 WHERE type = :type
+               )
+               SELECT guid FROM moz_bookmarks
+               WHERE id IN descendants
+              `, { id: item._id, type: this.TYPE_FOLDER });
+            if (rows.map(r => r.getResultByName("guid")).includes(updateInfo.parentGuid))
+              throw new Error("Cannot insert a folder into itself or one of its descendants");
+          }
+
+          parent = yield fetchBookmark({ guid: updateInfo.parentGuid });
+          if (!parent)
+            throw new Error("No bookmarks found for the provided parentGuid");
+        }
+
+        if (updateInfo.hasOwnProperty("index")) {
+          // If at this point we don't have a parent yet, we are moving into
+          // the same container.  Thus we know it exists.
+          if (!parent)
+            parent = yield fetchBookmark({ guid: item.parentGuid });
+
+          if (updateInfo.index >= parent._childCount ||
+              updateInfo.index == this.DEFAULT_INDEX) {
+             updateInfo.index = parent._childCount;
+
+            // Fix the index when moving within the same container.
+            if (parent.guid == item.parentGuid)
+               updateInfo.index--;
+          }
+        }
+
+        let updatedItem = yield updateBookmark(updateInfo, item, parent);
+
+        if (item.type == this.TYPE_BOOKMARK &&
+            item.url.href != updatedItem.url.href) {
+          // ...though we don't wait for the calculation.
+          updateFrecency(db, [item.url]).then(null, Cu.reportError);
+          updateFrecency(db, [updatedItem.url]).then(null, Cu.reportError);
+        }
+
+        // Notify onItemChanged to listeners.
+        let observers = PlacesUtils.bookmarks.getObservers();
+        // For lastModified, we only care about the original input, since we
+        // should not notify implciit lastModified changes.
+        if (info.hasOwnProperty("lastModified") &&
+            updateInfo.hasOwnProperty("lastModified") &&
+            item.lastModified != updatedItem.lastModified) {
+          notify(observers, "onItemChanged", [ updatedItem._id, "lastModified",
+                                               false,
+                                               `${PlacesUtils.toPRTime(updatedItem.lastModified)}`,
+                                               PlacesUtils.toPRTime(updatedItem.lastModified),
+                                               updatedItem.type,
+                                               updatedItem._parentId,
+                                               updatedItem.guid,
+                                               updatedItem.parentGuid, "",
+                                               updatedItem.source ]);
+        }
+        if (updateInfo.hasOwnProperty("title")) {
+          notify(observers, "onItemChanged", [ updatedItem._id, "title",
+                                               false, updatedItem.title,
+                                               PlacesUtils.toPRTime(updatedItem.lastModified),
+                                               updatedItem.type,
+                                               updatedItem._parentId,
+                                               updatedItem.guid,
+                                               updatedItem.parentGuid, "",
+                                               updatedItem.source ]);
+        }
+        if (updateInfo.hasOwnProperty("url")) {
+          notify(observers, "onItemChanged", [ updatedItem._id, "uri",
+                                               false, updatedItem.url.href,
+                                               PlacesUtils.toPRTime(updatedItem.lastModified),
+                                               updatedItem.type,
+                                               updatedItem._parentId,
+                                               updatedItem.guid,
+                                               updatedItem.parentGuid,
+                                               item.url.href,
+                                               updatedItem.source ]);
+        }
+        // If the item was moved, notify onItemMoved.
+        if (item.parentGuid != updatedItem.parentGuid ||
+            item.index != updatedItem.index) {
+          notify(observers, "onItemMoved", [ updatedItem._id, item._parentId,
+                                             item.index, updatedItem._parentId,
+                                             updatedItem.index, updatedItem.type,
+                                             updatedItem.guid, item.parentGuid,
+                                             updatedItem.parentGuid,
+                                             updatedItem.source ]);
+        }
+
+        // Remove non-enumerable properties.
+        delete updatedItem.source;
+        return Object.assign({}, updatedItem);
+      }.bind(this)));
+    }.bind(this));
+  },
+
+  /**
+   * Removes a bookmark-item.
+   *
+   * @param guidOrInfo
+   *        The globally unique identifier of the item to remove, or an
+   *        object representing it, as defined above.
+   * @param {Object} [options={}]
+   *        Additional options that can be passed to the function.
+   *        Currently supports the following properties:
+   *         - preventRemovalOfNonEmptyFolders: Causes an exception to be
+   *           thrown when attempting to remove a folder that is not empty.
+   *         - source: The change source, forwarded to all bookmark observers.
+   *           Defaults to nsINavBookmarksService::SOURCE_DEFAULT.
+   *
+   * @return {Promise} resolved when the removal is complete.
+   * @resolves to an object representing the removed bookmark.
+   * @rejects if the provided guid doesn't match any existing bookmark.
+   * @throws if the arguments are invalid.
+   */
+  remove(guidOrInfo, options={}) {
+    let info = guidOrInfo;
+    if (!info)
+      throw new Error("Input should be a valid object");
+    if (typeof(guidOrInfo) != "object")
+      info = { guid: guidOrInfo };
+
+    // Disallow removing the root folders.
+    if ([this.rootGuid, this.menuGuid, this.toolbarGuid, this.unfiledGuid,
+         this.tagsGuid, this.mobileGuid].includes(info.guid)) {
+      throw new Error("It's not possible to remove Places root folders.");
+    }
+
+    // Even if we ignore any other unneeded property, we still validate any
+    // known property to reduce likelihood of hidden bugs.
+    let removeInfo = validateBookmarkObject(info);
+
+    return Task.spawn(function* () {
+      let item = yield fetchBookmark(removeInfo);
+      if (!item)
+        throw new Error("No bookmarks found for the provided GUID.");
+
+      item = yield removeBookmark(item, options);
+
+      // Notify onItemRemoved to listeners.
+      let { source = Bookmarks.SOURCES.DEFAULT } = options;
+      let observers = PlacesUtils.bookmarks.getObservers();
+      let uri = item.hasOwnProperty("url") ? PlacesUtils.toURI(item.url) : null;
+      let isUntagging = item._grandParentId == PlacesUtils.tagsFolderId;
+      notify(observers, "onItemRemoved", [ item._id, item._parentId, item.index,
+                                           item.type, uri, item.guid,
+                                           item.parentGuid,
+                                           source ],
+                                         { isTagging: isUntagging });
+
+      if (isUntagging) {
+        for (let entry of (yield fetchBookmarksByURL(item))) {
+          notify(observers, "onItemChanged", [ entry._id, "tags", false, "",
+                                               PlacesUtils.toPRTime(entry.lastModified),
+                                               entry.type, entry._parentId,
+                                               entry.guid, entry.parentGuid,
+                                               "", source ]);
+        }
+      }
+
+      // Remove non-enumerable properties.
+      return Object.assign({}, item);
+    });
+  },
+
+  /**
+   * Removes ALL bookmarks, resetting the bookmarks storage to an empty tree.
+   *
+   * Note that roots are preserved, only their children will be removed.
+   *
+   * @param {Object} [options={}]
+   *        Additional options. Currently supports the following properties:
+   *         - source: The change source, forwarded to all bookmark observers.
+   *           Defaults to nsINavBookmarksService::SOURCE_DEFAULT.
+   *
+   * @return {Promise} resolved when the removal is complete.
+   * @resolves once the removal is complete.
+   */
+  eraseEverything: function(options={}) {
+    const folderGuids = [this.toolbarGuid, this.menuGuid, this.unfiledGuid,
+                         this.mobileGuid];
+    return PlacesUtils.withConnectionWrapper("Bookmarks.jsm: eraseEverything",
+      db => db.executeTransaction(function* () {
+        yield removeFoldersContents(db, folderGuids, options);
+        const time = PlacesUtils.toPRTime(new Date());
+        for (let folderGuid of folderGuids) {
+          yield db.executeCached(
+            `UPDATE moz_bookmarks SET lastModified = :time
+             WHERE id IN (SELECT id FROM moz_bookmarks WHERE guid = :folderGuid )
+            `, { folderGuid, time });
+        }
+      })
+    );
+  },
+
+  /**
+   * Returns a list of recently bookmarked items.
+   *
+   * @param {integer} numberOfItems
+   *        The maximum number of bookmark items to return.
+   *
+   * @return {Promise} resolved when the listing is complete.
+   * @resolves to an array of recent bookmark-items.
+   * @rejects if an error happens while querying.
+   */
+  getRecent(numberOfItems) {
+    if (numberOfItems === undefined) {
+      throw new Error("numberOfItems argument is required");
+    }
+    if (!typeof numberOfItems === 'number' || (numberOfItems % 1) !== 0) {
+      throw new Error("numberOfItems argument must be an integer");
+    }
+    if (numberOfItems <= 0) {
+      throw new Error("numberOfItems argument must be greater than zero");
+    }
+
+    return Task.spawn(function* () {
+      return yield fetchRecentBookmarks(numberOfItems);
+    });
+  },
+
+  /**
+   * Fetches information about a bookmark-item.
+   *
+   * REMARK: any successful call to this method resolves to a single
+   *         bookmark-item (or null), even when multiple bookmarks may exist
+   *         (e.g. fetching by url).  If you wish to retrieve all of the
+   *         bookmarks for a given match, use the callback instead.
+   *
+   * Input can be either a guid or an object with one, and only one, of these
+   * filtering properties set:
+   *  - guid
+   *      retrieves the item with the specified guid.
+   *  - parentGuid and index
+   *      retrieves the item by its position.
+   *  - url
+   *      retrieves the most recent bookmark having the given URL.
+   *      To retrieve ALL of the bookmarks for that URL, you must pass in an
+   *      onResult callback, that will be invoked once for each found bookmark.
+   *
+   * @param guidOrInfo
+   *        The globally unique identifier of the item to fetch, or an
+   *        object representing it, as defined above.
+   * @param onResult [optional]
+   *        Callback invoked for each found bookmark.
+   *
+   * @return {Promise} resolved when the fetch is complete.
+   * @resolves to an object representing the found item, as described above, or
+   *           an array of such objects.  if no item is found, the returned
+   *           promise is resolved to null.
+   * @rejects if an error happens while fetching.
+   * @throws if the arguments are invalid.
+   *
+   * @note Any unknown property in the info object is ignored.  Known properties
+   *       may be overwritten.
+   */
+  fetch(guidOrInfo, onResult=null) {
+    if (onResult && typeof onResult != "function")
+      throw new Error("onResult callback must be a valid function");
+    let info = guidOrInfo;
+    if (!info)
+      throw new Error("Input should be a valid object");
+    if (typeof(info) != "object")
+      info = { guid: guidOrInfo };
+
+    // Only one condition at a time can be provided.
+    let conditionsCount = [
+      v => v.hasOwnProperty("guid"),
+      v => v.hasOwnProperty("parentGuid") && v.hasOwnProperty("index"),
+      v => v.hasOwnProperty("url")
+    ].reduce((old, fn) => old + fn(info)|0, 0);
+    if (conditionsCount != 1)
+      throw new Error(`Unexpected number of conditions provided: ${conditionsCount}`);
+
+    // Even if we ignore any other unneeded property, we still validate any
+    // known property to reduce likelihood of hidden bugs.
+    let fetchInfo = validateBookmarkObject(info,
+      { parentGuid: { requiredIf: b => b.hasOwnProperty("index") }
+      , index: { requiredIf: b => b.hasOwnProperty("parentGuid")
+               , validIf: b => typeof(b.index) == "number" &&
+                               b.index >= 0 || b.index == this.DEFAULT_INDEX }
+      });
+
+    return Task.spawn(function* () {
+      let results;
+      if (fetchInfo.hasOwnProperty("guid"))
+        results = yield fetchBookmark(fetchInfo);
+      else if (fetchInfo.hasOwnProperty("parentGuid") && fetchInfo.hasOwnProperty("index"))
+        results = yield fetchBookmarkByPosition(fetchInfo);
+      else if (fetchInfo.hasOwnProperty("url"))
+        results = yield fetchBookmarksByURL(fetchInfo);
+
+      if (!results)
+        return null;
+
+      if (!Array.isArray(results))
+        results = [results];
+      // Remove non-enumerable properties.
+      results = results.map(r => Object.assign({}, r));
+
+      // Ideally this should handle an incremental behavior and thus be invoked
+      // while we fetch.  Though, the likelihood of 2 or more bookmarks for the
+      // same match is very low, so it's not worth the added code complication.
+      if (onResult) {
+        for (let result of results) {
+          try {
+            onResult(result);
+          } catch (ex) {
+            Cu.reportError(ex);
+          }
+        }
+      }
+
+      return results[0];
+    });
+  },
+
+  /**
+   * Retrieves an object representation of a bookmark-item, along with all of
+   * its descendants, if any.
+   *
+   * Each node in the tree is an object that extends the item representation
+   * described above with some additional properties:
+   *
+   *  - [deprecated] id (number)
+   *      the item's id.  Defined only if aOptions.includeItemIds is set.
+   *  - annos (array)
+   *      the item's annotations.  This is not set if there are no annotations
+   *      set for the item.
+   *
+   * The root object of the tree also has the following properties set:
+   *  - itemsCount (number, not enumerable)
+   *      the number of items, including the root item itself, which are
+   *      represented in the resolved object.
+   *
+   * Bookmarked URLs may also have the following properties:
+   *  - tags (string)
+   *      csv string of the bookmark's tags, if any.
+   *  - charset (string)
+   *      the last known charset of the bookmark, if any.
+   *  - iconurl (URL)
+   *      the bookmark's favicon URL, if any.
+   *
+   * Folders may also have the following properties:
+   *  - children (array)
+   *      the folder's children information, each of them having the same set of
+   *      properties as above.
+   *
+   * @param [optional] guid
+   *        the topmost item to be queried.  If it's not passed, the Places
+   *        root folder is queried: that is, you get a representation of the
+   *        entire bookmarks hierarchy.
+   * @param [optional] options
+   *        Options for customizing the query behavior, in the form of an
+   *        object with any of the following properties:
+   *         - excludeItemsCallback: a function for excluding items, along with
+   *           their descendants.  Given an item object (that has everything set
+   *           apart its potential children data), it should return true if the
+   *           item should be excluded.  Once an item is excluded, the function
+   *           isn't called for any of its descendants.  This isn't called for
+   *           the root item.
+   *           WARNING: since the function may be called for each item, using
+   *           this option can slow down the process significantly if the
+   *           callback does anything that's not relatively trivial.  It is
+   *           highly recommended to avoid any synchronous I/O or DB queries.
+   *         - includeItemIds: opt-in to include the deprecated id property.
+   *           Use it if you must. It'll be removed once the switch to guids is
+   *           complete.
+   *
+   * @return {Promise} resolved when the fetch is complete.
+   * @resolves to an object that represents either a single item or a
+   *           bookmarks tree.  if guid points to a non-existent item, the
+   *           returned promise is resolved to null.
+   * @rejects if an error happens while fetching.
+   * @throws if the arguments are invalid.
+   */
+  // TODO must implement these methods yet:
+  // PlacesUtils.promiseBookmarksTree()
+  fetchTree(guid = "", options = {}) {
+    throw new Error("Not yet implemented");
+  },
+
+  /**
+   * Reorders contents of a folder based on a provided array of GUIDs.
+   *
+   * @param parentGuid
+   *        The globally unique identifier of the folder whose contents should
+   *        be reordered.
+   * @param orderedChildrenGuids
+   *        Ordered array of the children's GUIDs.  If this list contains
+   *        non-existing entries they will be ignored.  If the list is
+   *        incomplete, missing entries will be appended.
+   * @param {Object} [options={}]
+   *        Additional options. Currently supports the following properties:
+   *         - source: The change source, forwarded to all bookmark observers.
+   *           Defaults to nsINavBookmarksService::SOURCE_DEFAULT.
+   *
+   * @return {Promise} resolved when reordering is complete.
+   * @rejects if an error happens while reordering.
+   * @throws if the arguments are invalid.
+   */
+  reorder(parentGuid, orderedChildrenGuids, options={}) {
+    let info = { guid: parentGuid, source: this.SOURCES.DEFAULT };
+    info = validateBookmarkObject(info, { guid: { required: true } });
+
+    if (!Array.isArray(orderedChildrenGuids) || !orderedChildrenGuids.length)
+      throw new Error("Must provide a sorted array of children GUIDs.");
+    try {
+      orderedChildrenGuids.forEach(PlacesUtils.BOOKMARK_VALIDATORS.guid);
+    } catch (ex) {
+      throw new Error("Invalid GUID found in the sorted children array.");
+    }
+
+    return Task.spawn(function* () {
+      let parent = yield fetchBookmark(info);
+      if (!parent || parent.type != this.TYPE_FOLDER)
+        throw new Error("No folder found for the provided GUID.");
+
+      let sortedChildren = yield reorderChildren(parent, orderedChildrenGuids);
+
+      let { source = Ci.nsINavBookmarksService.SOURCE_DEFAULT } = options;
+      let observers = PlacesUtils.bookmarks.getObservers();
+      // Note that child.index is the old index.
+      for (let i = 0; i < sortedChildren.length; ++i) {
+        let child = sortedChildren[i];
+        notify(observers, "onItemMoved", [ child._id, child._parentId,
+                                           child.index, child._parentId,
+                                           i, child.type,
+                                           child.guid, child.parentGuid,
+                                           child.parentGuid,
+                                           source ]);
+      }
+    }.bind(this));
+  },
+
+  /**
+   * Searches a list of bookmark-items by a search term, url or title.
+   *
+   * IMPORTANT:
+   * This is intended as an interim API for the web-extensions implementation.
+   * It will be removed as soon as we have a new querying API.
+   *
+   * If you just want to search bookmarks by URL, use .fetch() instead.
+   *
+   * @param query
+   *        Either a string to use as search term, or an object
+   *        containing any of these keys: query, title or url with the
+   *        corresponding string to match as value.
+   *        The url property can be either a string or an nsIURI.
+   *
+   * @return {Promise} resolved when the search is complete.
+   * @resolves to an array of found bookmark-items.
+   * @rejects if an error happens while searching.
+   * @throws if the arguments are invalid.
+   *
+   * @note Any unknown property in the query object is ignored.
+   *       Known properties may be overwritten.
+   */
+  search(query) {
+    if (!query) {
+      throw new Error("Query object is required");
+    }
+    if (typeof query === "string") {
+      query = { query: query };
+    }
+    if (typeof query !== "object") {
+      throw new Error("Query must be an object or a string");
+    }
+    if (query.query && typeof query.query !== "string") {
+      throw new Error("Query option must be a string");
+    }
+    if (query.title && typeof query.title !== "string") {
+      throw new Error("Title option must be a string");
+    }
+
+    if (query.url) {
+      if (typeof query.url === "string" || (query.url instanceof URL)) {
+        query.url = new URL(query.url).href;
+      } else if (query.url instanceof Ci.nsIURI) {
+        query.url = query.url.spec;
+      } else {
+        throw new Error("Url option must be a string or a URL object");
+      }
+    }
+
+    return Task.spawn(function* () {
+      let results = yield queryBookmarks(query);
+
+      return results;
+    });
+  },
+});
+
+// Globals.
+
+/**
+ * Sends a bookmarks notification through the given observers.
+ *
+ * @param observers
+ *        array of nsINavBookmarkObserver objects.
+ * @param notification
+ *        the notification name.
+ * @param args
+ *        array of arguments to pass to the notification.
+ * @param information
+ *        Information about the notification, so we can filter based
+ *        based on the observer's preferences.
+ */
+function notify(observers, notification, args, information = {}) {
+  for (let observer of observers) {
+    if (information.isTagging && observer.skipTags) {
+      continue;
+    }
+
+    if (information.isDescendantRemoval && observer.skipDescendantsOnItemRemoval) {
+      continue;
+    }
+
+    try {
+      observer[notification](...args);
+    } catch (ex) {}
+  }
+}
+
+// Update implementation.
+
+function updateBookmark(info, item, newParent) {
+  return PlacesUtils.withConnectionWrapper("Bookmarks.jsm: updateBookmark",
+    Task.async(function*(db) {
+
+    let tuples = new Map();
+    if (info.hasOwnProperty("lastModified"))
+      tuples.set("lastModified", { value: PlacesUtils.toPRTime(info.lastModified) });
+    if (info.hasOwnProperty("title"))
+      tuples.set("title", { value: info.title });
+
+    yield db.executeTransaction(function* () {
+      if (info.hasOwnProperty("url")) {
+        // Ensure a page exists in moz_places for this URL.
+        yield maybeInsertPlace(db, info.url);
+        // Update tuples for the update query.
+        tuples.set("url", { value: info.url.href
+                          , fragment: "fk = (SELECT id FROM moz_places WHERE url_hash = hash(:url) AND url = :url)" });
+      }
+
+      if (newParent) {
+        // For simplicity, update the index regardless.
+        let newIndex = info.hasOwnProperty("index") ? info.index : item.index;
+        tuples.set("position", { value: newIndex });
+
+        if (newParent.guid == item.parentGuid) {
+          // Moving inside the original container.
+          // When moving "up", add 1 to each index in the interval.
+          // Otherwise when moving down, we subtract 1.
+          let sign = newIndex < item.index ? +1 : -1;
+          yield db.executeCached(
+            `UPDATE moz_bookmarks SET position = position + :sign
+             WHERE parent = :newParentId
+               AND position BETWEEN :lowIndex AND :highIndex
+            `, { sign: sign, newParentId: newParent._id,
+                 lowIndex: Math.min(item.index, newIndex),
+                 highIndex: Math.max(item.index, newIndex) });
+        } else {
+          // Moving across different containers.
+          tuples.set("parent", { value: newParent._id} );
+          yield db.executeCached(
+            `UPDATE moz_bookmarks SET position = position + :sign
+             WHERE parent = :oldParentId
+               AND position >= :oldIndex
+            `, { sign: -1, oldParentId: item._parentId, oldIndex: item.index });
+          yield db.executeCached(
+            `UPDATE moz_bookmarks SET position = position + :sign
+             WHERE parent = :newParentId
+               AND position >= :newIndex
+            `, { sign: +1, newParentId: newParent._id, newIndex: newIndex });
+
+          yield setAncestorsLastModified(db, item.parentGuid, info.lastModified);
+        }
+        yield setAncestorsLastModified(db, newParent.guid, info.lastModified);
+      }
+
+      yield db.executeCached(
+        `UPDATE moz_bookmarks
+         SET ${Array.from(tuples.keys()).map(v => tuples.get(v).fragment || `${v} = :${v}`).join(", ")}
+         WHERE guid = :guid
+        `, Object.assign({ guid: info.guid },
+                         [...tuples.entries()].reduce((p, c) => { p[c[0]] = c[1].value; return p; }, {})));
+    });
+
+    // If the parent changed, update related non-enumerable properties.
+    let additionalParentInfo = {};
+    if (newParent) {
+      Object.defineProperty(additionalParentInfo, "_parentId",
+                            { value: newParent._id, enumerable: false });
+      Object.defineProperty(additionalParentInfo, "_grandParentId",
+                            { value: newParent._parentId, enumerable: false });
+    }
+
+    let updatedItem = mergeIntoNewObject(item, info, additionalParentInfo);
+
+    // Don't return an empty title to the caller.
+    if (updatedItem.hasOwnProperty("title") && updatedItem.title === null)
+      delete updatedItem.title;
+
+    return updatedItem;
+  }));
+}
+
+// Insert implementation.
+
+function insertBookmark(item, parent) {
+  return PlacesUtils.withConnectionWrapper("Bookmarks.jsm: insertBookmark",
+    Task.async(function*(db) {
+
+    // If a guid was not provided, generate one, so we won't need to fetch the
+    // bookmark just after having created it.
+    if (!item.hasOwnProperty("guid"))
+      item.guid = (yield db.executeCached("SELECT GENERATE_GUID() AS guid"))[0].getResultByName("guid");
+
+    yield db.executeTransaction(function* transaction() {
+      if (item.type == Bookmarks.TYPE_BOOKMARK) {
+        // Ensure a page exists in moz_places for this URL.
+        // The IGNORE conflict can trigger on `guid`.
+        yield maybeInsertPlace(db, item.url);
+      }
+
+      // Adjust indices.
+      yield db.executeCached(
+        `UPDATE moz_bookmarks SET position = position + 1
+         WHERE parent = :parent
+         AND position >= :index
+        `, { parent: parent._id, index: item.index });
+
+      // Insert the bookmark into the database.
+      yield db.executeCached(
+        `INSERT INTO moz_bookmarks (fk, type, parent, position, title,
+                                    dateAdded, lastModified, guid)
+         VALUES ((SELECT id FROM moz_places WHERE url_hash = hash(:url) AND url = :url), :type, :parent,
+                 :index, :title, :date_added, :last_modified, :guid)
+        `, { url: item.hasOwnProperty("url") ? item.url.href : "nonexistent",
+             type: item.type, parent: parent._id, index: item.index,
+             title: item.title, date_added: PlacesUtils.toPRTime(item.dateAdded),
+             last_modified: PlacesUtils.toPRTime(item.lastModified), guid: item.guid });
+
+      yield setAncestorsLastModified(db, item.parentGuid, item.dateAdded);
+    });
+
+    // If not a tag recalculate frecency...
+    let isTagging = parent._parentId == PlacesUtils.tagsFolderId;
+    if (item.type == Bookmarks.TYPE_BOOKMARK && !isTagging) {
+      // ...though we don't wait for the calculation.
+      updateFrecency(db, [item.url]).then(null, Cu.reportError);
+    }
+
+    // Don't return an empty title to the caller.
+    if (item.hasOwnProperty("title") && item.title === null)
+      delete item.title;
+
+    return item;
+  }));
+}
+
+// Query implementation.
+
+function queryBookmarks(info) {
+  let queryParams = {tags_folder: PlacesUtils.tagsFolderId};
+  // we're searching for bookmarks, so exclude tags
+  let queryString = "WHERE p.parent <> :tags_folder";
+
+  if (info.title) {
+    queryString += " AND b.title = :title";
+    queryParams.title = info.title;
+  }
+
+  if (info.url) {
+    queryString += " AND h.url_hash = hash(:url) AND h.url = :url";
+    queryParams.url = info.url;
+  }
+
+  if (info.query) {
+    queryString += " AND AUTOCOMPLETE_MATCH(:query, h.url, b.title, NULL, NULL, 1, 1, NULL, :matchBehavior, :searchBehavior) ";
+    queryParams.query = info.query;
+    queryParams.matchBehavior = MATCH_ANYWHERE_UNMODIFIED;
+    queryParams.searchBehavior = BEHAVIOR_BOOKMARK;
+  }
+
+  return PlacesUtils.withConnectionWrapper("Bookmarks.jsm: queryBookmarks",
+    Task.async(function*(db) {
+
+    // _id, _childCount, _grandParentId and _parentId fields
+    // are required to be in the result by the converting function
+    // hence setting them to NULL
+    let rows = yield db.executeCached(
+      `SELECT b.guid, IFNULL(p.guid, "") AS parentGuid, b.position AS 'index',
+              b.dateAdded, b.lastModified, b.type, b.title,
+              h.url AS url, b.parent, p.parent,
+              NULL AS _id,
+              NULL AS _childCount,
+              NULL AS _grandParentId,
+              NULL AS _parentId
+       FROM moz_bookmarks b
+       LEFT JOIN moz_bookmarks p ON p.id = b.parent
+       LEFT JOIN moz_places h ON h.id = b.fk
+       ${queryString}
+      `, queryParams);
+
+    return rowsToItemsArray(rows);
+  }));
+}
+
+
+// Fetch implementation.
+
+function fetchBookmark(info) {
+  return PlacesUtils.withConnectionWrapper("Bookmarks.jsm: fetchBookmark",
+    Task.async(function*(db) {
+
+    let rows = yield db.executeCached(
+      `SELECT b.guid, IFNULL(p.guid, "") AS parentGuid, b.position AS 'index',
+              b.dateAdded, b.lastModified, b.type, b.title, h.url AS url,
+              b.id AS _id, b.parent AS _parentId,
+              (SELECT count(*) FROM moz_bookmarks WHERE parent = b.id) AS _childCount,
+              p.parent AS _grandParentId
+       FROM moz_bookmarks b
+       LEFT JOIN moz_bookmarks p ON p.id = b.parent
+       LEFT JOIN moz_places h ON h.id = b.fk
+       WHERE b.guid = :guid
+      `, { guid: info.guid });
+
+    return rows.length ? rowsToItemsArray(rows)[0] : null;
+  }));
+}
+
+function fetchBookmarkByPosition(info) {
+  return PlacesUtils.withConnectionWrapper("Bookmarks.jsm: fetchBookmarkByPosition",
+    Task.async(function*(db) {
+    let index = info.index == Bookmarks.DEFAULT_INDEX ? null : info.index;
+
+    let rows = yield db.executeCached(
+      `SELECT b.guid, IFNULL(p.guid, "") AS parentGuid, b.position AS 'index',
+              b.dateAdded, b.lastModified, b.type, b.title, h.url AS url,
+              b.id AS _id, b.parent AS _parentId,
+              (SELECT count(*) FROM moz_bookmarks WHERE parent = b.id) AS _childCount,
+              p.parent AS _grandParentId
+       FROM moz_bookmarks b
+       LEFT JOIN moz_bookmarks p ON p.id = b.parent
+       LEFT JOIN moz_places h ON h.id = b.fk
+       WHERE p.guid = :parentGuid
+       AND b.position = IFNULL(:index, (SELECT count(*) - 1
+                                        FROM moz_bookmarks
+                                        WHERE parent = p.id))
+      `, { parentGuid: info.parentGuid, index });
+
+    return rows.length ? rowsToItemsArray(rows)[0] : null;
+  }));
+}
+
+function fetchBookmarksByURL(info) {
+  return PlacesUtils.withConnectionWrapper("Bookmarks.jsm: fetchBookmarksByURL",
+    Task.async(function*(db) {
+
+    let rows = yield db.executeCached(
+      `/* do not warn (bug no): not worth to add an index */
+       SELECT b.guid, IFNULL(p.guid, "") AS parentGuid, b.position AS 'index',
+              b.dateAdded, b.lastModified, b.type, b.title, h.url AS url,
+              b.id AS _id, b.parent AS _parentId,
+              (SELECT count(*) FROM moz_bookmarks WHERE parent = b.id) AS _childCount,
+              p.parent AS _grandParentId
+       FROM moz_bookmarks b
+       LEFT JOIN moz_bookmarks p ON p.id = b.parent
+       LEFT JOIN moz_places h ON h.id = b.fk
+       WHERE h.url_hash = hash(:url) AND h.url = :url
+       AND _grandParentId <> :tags_folder
+       ORDER BY b.lastModified DESC
+      `, { url: info.url.href,
+           tags_folder: PlacesUtils.tagsFolderId });
+
+    return rows.length ? rowsToItemsArray(rows) : null;
+  }));
+}
+
+function fetchRecentBookmarks(numberOfItems) {
+  return PlacesUtils.withConnectionWrapper("Bookmarks.jsm: fetchRecentBookmarks",
+    Task.async(function*(db) {
+
+    let rows = yield db.executeCached(
+      `SELECT b.guid, IFNULL(p.guid, "") AS parentGuid, b.position AS 'index',
+              b.dateAdded, b.lastModified, b.type, b.title, h.url AS url,
+              NULL AS _id, NULL AS _parentId, NULL AS _childCount, NULL AS _grandParentId
+       FROM moz_bookmarks b
+       LEFT JOIN moz_bookmarks p ON p.id = b.parent
+       LEFT JOIN moz_places h ON h.id = b.fk
+       WHERE p.parent <> :tags_folder
+       ORDER BY b.dateAdded DESC, b.ROWID DESC
+       LIMIT :numberOfItems
+      `, { tags_folder: PlacesUtils.tagsFolderId, numberOfItems });
+
+    return rows.length ? rowsToItemsArray(rows) : [];
+  }));
+}
+
+function fetchBookmarksByParent(info) {
+  return PlacesUtils.withConnectionWrapper("Bookmarks.jsm: fetchBookmarksByParent",
+    Task.async(function*(db) {
+
+    let rows = yield db.executeCached(
+      `SELECT b.guid, IFNULL(p.guid, "") AS parentGuid, b.position AS 'index',
+              b.dateAdded, b.lastModified, b.type, b.title, h.url AS url,
+              b.id AS _id, b.parent AS _parentId,
+              (SELECT count(*) FROM moz_bookmarks WHERE parent = b.id) AS _childCount,
+              p.parent AS _grandParentId
+       FROM moz_bookmarks b
+       LEFT JOIN moz_bookmarks p ON p.id = b.parent
+       LEFT JOIN moz_places h ON h.id = b.fk
+       WHERE p.guid = :parentGuid
+       ORDER BY b.position ASC
+      `, { parentGuid: info.parentGuid });
+
+    return rowsToItemsArray(rows);
+  }));
+}
+
+// Remove implementation.
+
+function removeBookmark(item, options) {
+  return PlacesUtils.withConnectionWrapper("Bookmarks.jsm: removeBookmark",
+    Task.async(function*(db) {
+
+    let isUntagging = item._grandParentId == PlacesUtils.tagsFolderId;
+
+    yield db.executeTransaction(function* transaction() {
+      // If it's a folder, remove its contents first.
+      if (item.type == Bookmarks.TYPE_FOLDER) {
+        if (options.preventRemovalOfNonEmptyFolders && item._childCount > 0) {
+          throw new Error("Cannot remove a non-empty folder.");
+        }
+        yield removeFoldersContents(db, [item.guid], options);
+      }
+
+      // Remove annotations first.  If it's a tag, we can avoid paying that cost.
+      if (!isUntagging) {
+        // We don't go through the annotations service for this cause otherwise
+        // we'd get a pointless onItemChanged notification and it would also
+        // set lastModified to an unexpected value.
+        yield removeAnnotationsForItem(db, item._id);
+      }
+
+      // Remove the bookmark from the database.
+      yield db.executeCached(
+        `DELETE FROM moz_bookmarks WHERE guid = :guid`, { guid: item.guid });
+
+      // Fix indices in the parent.
+      yield db.executeCached(
+        `UPDATE moz_bookmarks SET position = position - 1 WHERE
+         parent = :parentId AND position > :index
+        `, { parentId: item._parentId, index: item.index });
+
+      yield setAncestorsLastModified(db, item.parentGuid, new Date());
+    });
+
+    // If not a tag recalculate frecency...
+    if (item.type == Bookmarks.TYPE_BOOKMARK && !isUntagging) {
+      // ...though we don't wait for the calculation.
+      updateFrecency(db, [item.url]).then(null, Cu.reportError);
+    }
+
+    return item;
+  }));
+}
+
+// Reorder implementation.
+
+function reorderChildren(parent, orderedChildrenGuids) {
+  return PlacesUtils.withConnectionWrapper("Bookmarks.jsm: updateBookmark",
+    db => db.executeTransaction(function* () {
+      // Select all of the direct children for the given parent.
+      let children = yield fetchBookmarksByParent({ parentGuid: parent.guid });
+      if (!children.length)
+        return undefined;
+
+      // Build a map of GUIDs to indices for fast lookups in the comparator
+      // function.
+      let guidIndices = new Map();
+      for (let i = 0; i < orderedChildrenGuids.length; ++i) {
+        let guid = orderedChildrenGuids[i];
+        guidIndices.set(guid, i);
+      }
+
+      // Reorder the children array according to the specified order, provided
+      // GUIDs come first, others are appended in somehow random order.
+      children.sort((a, b) => {
+        // This works provided fetchBookmarksByParent returns sorted children.
+        if (!guidIndices.has(a.guid) && !guidIndices.has(b.guid)) {
+          return 0;
+        }
+        if (!guidIndices.has(a.guid)) {
+          return 1;
+        }
+        if (!guidIndices.has(b.guid)) {
+          return -1;
+        }
+        return guidIndices.get(a.guid) < guidIndices.get(b.guid) ? -1 : 1;
+       });
+
+      // Update the bookmarks position now.  If any unknown guid have been
+      // inserted meanwhile, its position will be set to -position, and we'll
+      // handle it later.
+      // To do the update in a single step, we build a VALUES (guid, position)
+      // table.  We then use count() in the sorting table to avoid skipping values
+      // when no more existing GUIDs have been provided.
+      let valuesTable = children.map((child, i) => `("${child.guid}", ${i})`)
+                                .join();
+      yield db.execute(
+        `WITH sorting(g, p) AS (
+           VALUES ${valuesTable}
+         )
+         UPDATE moz_bookmarks SET position = (
+           SELECT CASE count(*) WHEN 0 THEN -position
+                                       ELSE count(*) - 1
+                  END
+           FROM sorting a
+           JOIN sorting b ON b.p <= a.p
+           WHERE a.g = guid
+         )
+         WHERE parent = :parentId
+        `, { parentId: parent._id});
+
+      // Update position of items that could have been inserted in the meanwhile.
+      // Since this can happen rarely and it's only done for schema coherence
+      // resonds, we won't notify about these changes.
+      yield db.executeCached(
+        `CREATE TEMP TRIGGER moz_bookmarks_reorder_trigger
+           AFTER UPDATE OF position ON moz_bookmarks
+           WHEN NEW.position = -1
+         BEGIN
+           UPDATE moz_bookmarks
+           SET position = (SELECT MAX(position) FROM moz_bookmarks
+                           WHERE parent = NEW.parent) +
+                          (SELECT count(*) FROM moz_bookmarks
+                           WHERE parent = NEW.parent
+                             AND position BETWEEN OLD.position AND -1)
+           WHERE guid = NEW.guid;
+         END
+        `);
+
+      yield db.executeCached(
+        `UPDATE moz_bookmarks SET position = -1 WHERE position < 0`);
+
+      yield db.executeCached(`DROP TRIGGER moz_bookmarks_reorder_trigger`);
+
+      return children;
+    }.bind(this))
+  );
+}
+
+// Helpers.
+
+/**
+ * Merges objects into a new object, included non-enumerable properties.
+ *
+ * @param sources
+ *        source objects to merge.
+ * @return a new object including all properties from the source objects.
+ */
+function mergeIntoNewObject(...sources) {
+  let dest = {};
+  for (let src of sources) {
+    for (let prop of Object.getOwnPropertyNames(src)) {
+      Object.defineProperty(dest, prop, Object.getOwnPropertyDescriptor(src, prop));
+    }
+  }
+  return dest;
+}
+
+/**
+ * Remove properties that have the same value across two bookmark objects.
+ *
+ * @param dest
+ *        destination bookmark object.
+ * @param src
+ *        source bookmark object.
+ * @return a cleaned up bookmark object.
+ * @note "guid" is never removed.
+ */
+function removeSameValueProperties(dest, src) {
+  for (let prop in dest) {
+    let remove = false;
+    switch (prop) {
+      case "lastModified":
+      case "dateAdded":
+        remove = src.hasOwnProperty(prop) && dest[prop].getTime() == src[prop].getTime();
+        break;
+      case "url":
+        remove = src.hasOwnProperty(prop) && dest[prop].href == src[prop].href;
+        break;
+      default:
+        remove = dest[prop] == src[prop];
+    }
+    if (remove && prop != "guid")
+      delete dest[prop];
+  }
+}
+
+/**
+ * Convert an array of mozIStorageRow objects to an array of bookmark objects.
+ *
+ * @param rows
+ *        the array of mozIStorageRow objects.
+ * @return an array of bookmark objects.
+ */
+function rowsToItemsArray(rows) {
+  return rows.map(row => {
+    let item = {};
+    for (let prop of ["guid", "index", "type"]) {
+      item[prop] = row.getResultByName(prop);
+    }
+    for (let prop of ["dateAdded", "lastModified"]) {
+      item[prop] = PlacesUtils.toDate(row.getResultByName(prop));
+    }
+    for (let prop of ["title", "parentGuid", "url" ]) {
+      let val = row.getResultByName(prop);
+      if (val)
+        item[prop] = prop === "url" ? new URL(val) : val;
+    }
+    for (let prop of ["_id", "_parentId", "_childCount", "_grandParentId"]) {
+      let val = row.getResultByName(prop);
+      if (val !== null) {
+        // These properties should not be returned to the API consumer, thus
+        // they are non-enumerable and removed through Object.assign just before
+        // the object is returned.
+        // Configurable is set to support mergeIntoNewObject overwrites.
+        Object.defineProperty(item, prop, { value: val, enumerable: false,
+                                                        configurable: true });
+      }
+    }
+
+    return item;
+  });
+}
+
+function validateBookmarkObject(input, behavior) {
+  return PlacesUtils.validateItemProperties(
+    PlacesUtils.BOOKMARK_VALIDATORS, input, behavior);
+}
+
+/**
+ * Updates frecency for a list of URLs.
+ *
+ * @param db
+ *        the Sqlite.jsm connection handle.
+ * @param urls
+ *        the array of URLs to update.
+ */
+var updateFrecency = Task.async(function* (db, urls) {
+  // We just use the hashes, since updating a few additional urls won't hurt.
+  yield db.execute(
+    `UPDATE moz_places
+     SET frecency = NOTIFY_FRECENCY(
+       CALCULATE_FRECENCY(id), url, guid, hidden, last_visit_date
+     ) WHERE url_hash IN ( ${urls.map(url => `hash("${url.href}")`).join(", ")} )
+    `);
+
+  yield db.execute(
+    `UPDATE moz_places
+     SET hidden = 0
+     WHERE url_hash IN ( ${urls.map(url => `hash(${JSON.stringify(url.href)})`).join(", ")} )
+       AND frecency <> 0
+    `);
+});
+
+/**
+ * Removes any orphan annotation entries.
+ *
+ * @param db
+ *        the Sqlite.jsm connection handle.
+ */
+var removeOrphanAnnotations = Task.async(function* (db) {
+  yield db.executeCached(
+    `DELETE FROM moz_items_annos
+     WHERE id IN (SELECT a.id from moz_items_annos a
+                  LEFT JOIN moz_bookmarks b ON a.item_id = b.id
+                  WHERE b.id ISNULL)
+    `);
+  yield db.executeCached(
+    `DELETE FROM moz_anno_attributes
+     WHERE id IN (SELECT n.id from moz_anno_attributes n
+                  LEFT JOIN moz_annos a1 ON a1.anno_attribute_id = n.id
+                  LEFT JOIN moz_items_annos a2 ON a2.anno_attribute_id = n.id
+                  WHERE a1.id ISNULL AND a2.id ISNULL)
+    `);
+});
+
+/**
+ * Removes annotations for a given item.
+ *
+ * @param db
+ *        the Sqlite.jsm connection handle.
+ * @param itemId
+ *        internal id of the item for which to remove annotations.
+ */
+var removeAnnotationsForItem = Task.async(function* (db, itemId) {
+  yield db.executeCached(
+    `DELETE FROM moz_items_annos
+     WHERE item_id = :id
+    `, { id: itemId });
+  yield db.executeCached(
+    `DELETE FROM moz_anno_attributes
+     WHERE id IN (SELECT n.id from moz_anno_attributes n
+                  LEFT JOIN moz_annos a1 ON a1.anno_attribute_id = n.id
+                  LEFT JOIN moz_items_annos a2 ON a2.anno_attribute_id = n.id
+                  WHERE a1.id ISNULL AND a2.id ISNULL)
+    `);
+});
+
+/**
+ * Updates lastModified for all the ancestors of a given folder GUID.
+ *
+ * @param db
+ *        the Sqlite.jsm connection handle.
+ * @param folderGuid
+ *        the GUID of the folder whose ancestors should be updated.
+ * @param time
+ *        a Date object to use for the update.
+ *
+ * @note the folder itself is also updated.
+ */
+var setAncestorsLastModified = Task.async(function* (db, folderGuid, time) {
+  yield db.executeCached(
+    `WITH RECURSIVE
+     ancestors(aid) AS (
+       SELECT id FROM moz_bookmarks WHERE guid = :guid
+       UNION ALL
+       SELECT parent FROM moz_bookmarks
+       JOIN ancestors ON id = aid
+       WHERE type = :type
+     )
+     UPDATE moz_bookmarks SET lastModified = :time
+     WHERE id IN ancestors
+    `, { guid: folderGuid, type: Bookmarks.TYPE_FOLDER,
+         time: PlacesUtils.toPRTime(time) });
+});
+
+/**
+ * Remove all descendants of one or more bookmark folders.
+ *
+ * @param db
+ *        the Sqlite.jsm connection handle.
+ * @param folderGuids
+ *        array of folder guids.
+ */
+var removeFoldersContents =
+Task.async(function* (db, folderGuids, options) {
+  let itemsRemoved = [];
+  for (let folderGuid of folderGuids) {
+    let rows = yield db.executeCached(
+      `WITH RECURSIVE
+       descendants(did) AS (
+         SELECT b.id FROM moz_bookmarks b
+         JOIN moz_bookmarks p ON b.parent = p.id
+         WHERE p.guid = :folderGuid
+         UNION ALL
+         SELECT id FROM moz_bookmarks
+         JOIN descendants ON parent = did
+       )
+       SELECT b.id AS _id, b.parent AS _parentId, b.position AS 'index',
+              b.type, url, b.guid, p.guid AS parentGuid, b.dateAdded,
+              b.lastModified, b.title, p.parent AS _grandParentId,
+              NULL AS _childCount
+       FROM descendants
+       JOIN moz_bookmarks b ON did = b.id
+       JOIN moz_bookmarks p ON p.id = b.parent
+       LEFT JOIN moz_places h ON b.fk = h.id`, { folderGuid });
+
+    itemsRemoved = itemsRemoved.concat(rowsToItemsArray(rows));
+
+    yield db.executeCached(
+      `WITH RECURSIVE
+       descendants(did) AS (
+         SELECT b.id FROM moz_bookmarks b
+         JOIN moz_bookmarks p ON b.parent = p.id
+         WHERE p.guid = :folderGuid
+         UNION ALL
+         SELECT id FROM moz_bookmarks
+         JOIN descendants ON parent = did
+       )
+       DELETE FROM moz_bookmarks WHERE id IN descendants`, { folderGuid });
+  }
+
+  // Cleanup orphans.
+  yield removeOrphanAnnotations(db);
+
+  // TODO (Bug 1087576): this may leave orphan tags behind.
+
+  let urls = itemsRemoved.filter(item => "url" in item).map(item => item.url);
+  updateFrecency(db, urls).then(null, Cu.reportError);
+
+  // Send onItemRemoved notifications to listeners.
+  // TODO (Bug 1087580): for the case of eraseEverything, this should send a
+  // single clear bookmarks notification rather than notifying for each
+  // bookmark.
+
+  // Notify listeners in reverse order to serve children before parents.
+  let { source = Ci.nsINavBookmarksService.SOURCE_DEFAULT } = options;
+  let observers = PlacesUtils.bookmarks.getObservers();
+  for (let item of itemsRemoved.reverse()) {
+    let uri = item.hasOwnProperty("url") ? PlacesUtils.toURI(item.url) : null;
+    notify(observers, "onItemRemoved", [ item._id, item._parentId,
+                                         item.index, item.type, uri,
+                                         item.guid, item.parentGuid,
+                                         source ],
+                                       // Notify observers that this item is being
+                                       // removed as a descendent.
+                                       { isDescendantRemoval: true });
+
+    let isUntagging = item._grandParentId == PlacesUtils.tagsFolderId;
+    if (isUntagging) {
+      for (let entry of (yield fetchBookmarksByURL(item))) {
+        notify(observers, "onItemChanged", [ entry._id, "tags", false, "",
+                                             PlacesUtils.toPRTime(entry.lastModified),
+                                             entry.type, entry._parentId,
+                                             entry.guid, entry.parentGuid,
+                                             "", source ]);
+      }
+    }
+  }
+});
+
+/**
+ * Tries to insert a new place if it doesn't exist yet.
+ * @param url
+ *        A valid URL object.
+ * @return {Promise} resolved when the operation is complete.
+ */
+function maybeInsertPlace(db, url) {
+  // The IGNORE conflict can trigger on `guid`.
+  return db.executeCached(
+    `INSERT OR IGNORE INTO moz_places (url, url_hash, rev_host, hidden, frecency, guid)
+     VALUES (:url, hash(:url), :rev_host, 0, :frecency,
+             IFNULL((SELECT guid FROM moz_places WHERE url_hash = hash(:url) AND url = :url),
+                    GENERATE_GUID()))
+    `, { url: url.href,
+         rev_host: PlacesUtils.getReversedHost(url),
+         frecency: url.protocol == "place:" ? 0 : -1 });
+}