Adding upstream version 115.7.0esr.upstream/115.7.0esr

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

1 files changed, 1443 insertions, 0 deletions

diff --git a/toolkit/components/places/PlacesDBUtils.sys.mjs b/toolkit/components/places/PlacesDBUtils.sys.mjs
new file mode 100644
index 0000000000..05a771efad
--- /dev/null
+++ b/toolkit/components/places/PlacesDBUtils.sys.mjs
@@ -0,0 +1,1443 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ * vim: sw=2 ts=2 sts=2 expandtab filetype=javascript
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const BYTES_PER_MEBIBYTE = 1048576;
+const MS_PER_DAY = 86400000;
+// Threshold value for removeOldCorruptDBs.
+// Corrupt DBs older than this value are removed.
+const CORRUPT_DB_RETAIN_DAYS = 14;
+
+// Seconds between maintenance runs.
+const MAINTENANCE_INTERVAL_SECONDS = 7 * 86400;
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  PlacesPreviews: "resource://gre/modules/PlacesPreviews.sys.mjs",
+  PlacesUtils: "resource://gre/modules/PlacesUtils.sys.mjs",
+  Sqlite: "resource://gre/modules/Sqlite.sys.mjs",
+});
+
+export var PlacesDBUtils = {
+  _isShuttingDown: false,
+
+  _clearTaskQueue: false,
+  clearPendingTasks() {
+    PlacesDBUtils._clearTaskQueue = true;
+  },
+
+  /**
+   * Executes integrity check and common maintenance tasks.
+   *
+   * @return a Map[taskName(String) -> Object]. The Object has the following properties:
+   *         - succeeded: boolean
+   *         - logs: an array of strings containing the messages logged by the task.
+   */
+  async maintenanceOnIdle() {
+    let tasks = [
+      this.checkIntegrity,
+      this.invalidateCaches,
+      this.checkCoherence,
+      this._refreshUI,
+      this.originFrecencyStats,
+      this.incrementalVacuum,
+      this.removeOldCorruptDBs,
+      this.deleteOrphanPreviews,
+    ];
+    let telemetryStartTime = Date.now();
+    let taskStatusMap = await PlacesDBUtils.runTasks(tasks);
+
+    Services.prefs.setIntPref(
+      "places.database.lastMaintenance",
+      parseInt(Date.now() / 1000)
+    );
+    Services.telemetry
+      .getHistogramById("PLACES_IDLE_MAINTENANCE_TIME_MS")
+      .add(Date.now() - telemetryStartTime);
+    return taskStatusMap;
+  },
+
+  /**
+   * Executes integrity check, common and advanced maintenance tasks (like
+   * expiration and vacuum).  Will also collect statistics on the database.
+   *
+   * Note: although this function isn't actually async, we keep it async to
+   * allow us to maintain a simple, consistent API for the tasks within this object.
+   *
+   * @return {Promise}
+   *        A promise that resolves with a Map[taskName(String) -> Object].
+   *        The Object has the following properties:
+   *         - succeeded: boolean
+   *         - logs: an array of strings containing the messages logged by the task.
+   */
+  async checkAndFixDatabase() {
+    let tasks = [
+      this.checkIntegrity,
+      this.invalidateCaches,
+      this.checkCoherence,
+      this.expire,
+      this.originFrecencyStats,
+      this.vacuum,
+      this.stats,
+      this._refreshUI,
+    ];
+    return PlacesDBUtils.runTasks(tasks);
+  },
+
+  /**
+   * Forces a full refresh of Places views.
+   *
+   * Note: although this function isn't actually async, we keep it async to
+   * allow us to maintain a simple, consistent API for the tasks within this object.
+   *
+   * @returns {Array} An empty array.
+   */
+  async _refreshUI() {
+    PlacesObservers.notifyListeners([new PlacesPurgeCaches()]);
+    return [];
+  },
+
+  /**
+   * Checks integrity and tries to fix the database through a reindex.
+   *
+   * @return {Promise} resolves if database is sane or is made sane.
+   * @resolves to an array of logs for this task.
+   * @rejects if we're unable to fix corruption or unable to check status.
+   */
+  async checkIntegrity() {
+    let logs = [];
+
+    async function check(dbName) {
+      try {
+        await integrity(dbName);
+        logs.push(`The ${dbName} database is sane`);
+      } catch (ex) {
+        PlacesDBUtils.clearPendingTasks();
+        if (ex.result == Cr.NS_ERROR_FILE_CORRUPTED) {
+          logs.push(`The ${dbName} database is corrupt`);
+          Services.prefs.setCharPref(
+            "places.database.replaceDatabaseOnStartup",
+            dbName
+          );
+          throw new Error(
+            `Unable to fix corruption, ${dbName} will be replaced on next startup`
+          );
+        }
+        throw new Error(`Unable to check ${dbName} integrity: ${ex}`);
+      }
+    }
+
+    await check("places.sqlite");
+    await check("favicons.sqlite");
+
+    return logs;
+  },
+
+  invalidateCaches() {
+    let logs = [];
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "PlacesDBUtils: invalidate caches",
+      async db => {
+        let idsWithStaleGuidsRows = await db.execute(
+          `SELECT id FROM moz_bookmarks
+           WHERE guid IS NULL OR
+                 NOT IS_VALID_GUID(guid) OR
+                 (type = :bookmark_type AND fk IS NULL) OR
+                 (type <> :bookmark_type AND fk NOT NULL) OR
+                 type IS NULL`,
+          { bookmark_type: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK }
+        );
+        for (let row of idsWithStaleGuidsRows) {
+          let id = row.getResultByName("id");
+          lazy.PlacesUtils.invalidateCachedGuidFor(id);
+        }
+        logs.push("The caches have been invalidated");
+        return logs;
+      }
+    ).catch(ex => {
+      PlacesDBUtils.clearPendingTasks();
+      throw new Error("Unable to invalidate caches");
+    });
+  },
+
+  /**
+   * Checks data coherence and tries to fix most common errors.
+   *
+   * @return {Promise} resolves when coherence is checked.
+   * @resolves to an array of logs for this task.
+   * @rejects if database is not coherent.
+   */
+  async checkCoherence() {
+    let logs = [];
+    let stmts = await PlacesDBUtils._getCoherenceStatements();
+    let coherenceCheck = true;
+    await lazy.PlacesUtils.withConnectionWrapper(
+      "PlacesDBUtils: coherence check:",
+      db =>
+        db.executeTransaction(async () => {
+          for (let { query, params } of stmts) {
+            try {
+              await db.execute(query, params || null);
+            } catch (ex) {
+              console.error(ex);
+              coherenceCheck = false;
+            }
+          }
+        })
+    );
+
+    if (coherenceCheck) {
+      logs.push("The database is coherent");
+    } else {
+      PlacesDBUtils.clearPendingTasks();
+      throw new Error("Unable to complete the coherence check");
+    }
+    return logs;
+  },
+
+  /**
+   * Runs incremental vacuum on databases supporting it.
+   *
+   * @return {Promise} resolves when done.
+   * @resolves to an array of logs for this task.
+   * @rejects if we were unable to vacuum.
+   */
+  async incrementalVacuum() {
+    let logs = [];
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "PlacesDBUtils: incrementalVacuum",
+      async db => {
+        let count = (
+          await db.execute("PRAGMA favicons.freelist_count")
+        )[0].getResultByIndex(0);
+        if (count < 10) {
+          logs.push(
+            `The favicons database has only ${count} free pages, not vacuuming.`
+          );
+        } else {
+          logs.push(
+            `The favicons database has ${count} free pages, vacuuming.`
+          );
+          await db.execute("PRAGMA favicons.incremental_vacuum");
+          count = (
+            await db.execute("PRAGMA favicons.freelist_count")
+          )[0].getResultByIndex(0);
+          logs.push(
+            `The database has been vacuumed and has now ${count} free pages.`
+          );
+        }
+        return logs;
+      }
+    ).catch(ex => {
+      PlacesDBUtils.clearPendingTasks();
+      throw new Error(
+        "Unable to incrementally vacuum the favicons database " + ex
+      );
+    });
+  },
+
+  /**
+   * Expire orphan previews that don't have a Places entry anymore.
+   *
+   * @return {Promise} resolves when done.
+   * @resolves to an array of logs for this task.
+   */
+  async deleteOrphanPreviews() {
+    let logs = [];
+    try {
+      let deleted = await lazy.PlacesPreviews.deleteOrphans();
+      if (deleted) {
+        logs.push(`Orphan previews deleted.`);
+      }
+    } catch (ex) {
+      throw new Error("Unable to delete orphan previews " + ex);
+    }
+    return logs;
+  },
+
+  async _getCoherenceStatements() {
+    let cleanupStatements = [
+      // MOZ_PLACES
+      // L.1 remove duplicate URLs.
+      // This task uses a temp table of potential dupes, and a trigger to remove
+      // them. It runs first because it relies on subsequent tasks to clean up
+      // orphaned foreign key references. The task works like this: first, we
+      // insert all rows with the same hash into the temp table. This lets
+      // SQLite use the `url_hash` index for scanning `moz_places`. Hashes
+      // aren't unique, so two different URLs might have the same hash. To find
+      // the actual dupes, we use a unique constraint on the URL in the temp
+      // table. If that fails, we bump the dupe count. Then, we delete all dupes
+      // from the table. This fires the cleanup trigger, which updates all
+      // foreign key references to point to one of the duplicate Places, then
+      // deletes the others.
+      {
+        query: `CREATE TEMP TABLE IF NOT EXISTS moz_places_dupes_temp(
+          id INTEGER PRIMARY KEY
+        , hash INTEGER NOT NULL
+        , url TEXT UNIQUE NOT NULL
+        , count INTEGER NOT NULL DEFAULT 0
+        )`,
+      },
+      {
+        query: `CREATE TEMP TRIGGER IF NOT EXISTS moz_places_remove_dupes_temp_trigger
+        AFTER DELETE ON moz_places_dupes_temp
+        FOR EACH ROW
+        BEGIN
+          /* Reassign history visits. */
+          UPDATE moz_historyvisits SET
+            place_id = OLD.id
+          WHERE place_id IN (SELECT id FROM moz_places
+                             WHERE id <> OLD.id AND
+                                   url_hash = OLD.hash AND
+                                   url = OLD.url);
+
+          /* Merge autocomplete history entries. */
+          INSERT INTO moz_inputhistory(place_id, input, use_count)
+          SELECT OLD.id, a.input, a.use_count
+          FROM moz_inputhistory a
+          JOIN moz_places h ON h.id = a.place_id
+          WHERE h.id <> OLD.id AND
+                h.url_hash = OLD.hash AND
+                h.url = OLD.url
+          ON CONFLICT(place_id, input) DO UPDATE SET
+            place_id = excluded.place_id,
+            use_count = use_count + excluded.use_count;
+
+          /* Merge page annos, ignoring annos with the same name that are
+             already set on the destination. */
+          INSERT OR IGNORE INTO moz_annos(id, place_id, anno_attribute_id,
+                                          content, flags, expiration, type,
+                                          dateAdded, lastModified)
+          SELECT (SELECT k.id FROM moz_annos k
+                  WHERE k.place_id = OLD.id AND
+                        k.anno_attribute_id = a.anno_attribute_id), OLD.id,
+                 a.anno_attribute_id, a.content, a.flags, a.expiration, a.type,
+                 a.dateAdded, a.lastModified
+          FROM moz_annos a
+          JOIN moz_places h ON h.id = a.place_id
+          WHERE h.id <> OLD.id AND
+                url_hash = OLD.hash AND
+                url = OLD.url;
+
+          /* Reassign bookmarks, and bump the Sync change counter just in case
+             we have new keywords. */
+          UPDATE moz_bookmarks SET
+            fk = OLD.id,
+            syncChangeCounter = syncChangeCounter + 1
+          WHERE fk IN (SELECT id FROM moz_places
+                       WHERE url_hash = OLD.hash AND
+                             url = OLD.url);
+
+          /* Reassign keywords. */
+          UPDATE moz_keywords SET
+            place_id = OLD.id
+          WHERE place_id IN (SELECT id FROM moz_places
+                             WHERE id <> OLD.id AND
+                                   url_hash = OLD.hash AND
+                                   url = OLD.url);
+
+          /* Now that we've updated foreign key references, drop the
+             conflicting source. */
+          DELETE FROM moz_places
+          WHERE id <> OLD.id AND
+                url_hash = OLD.hash AND
+                url = OLD.url;
+
+          /* Recalculate frecency for the destination. */
+          UPDATE moz_places SET recalc_frecency = 1, recalc_alt_frecency = 1
+          WHERE id = OLD.id;
+        END`,
+      },
+      {
+        query: `INSERT INTO moz_places_dupes_temp(id, hash, url, count)
+        SELECT h.id, h.url_hash, h.url, 1
+        FROM moz_places h
+        JOIN (SELECT url_hash FROM moz_places
+              GROUP BY url_hash
+              HAVING count(*) > 1) d ON d.url_hash = h.url_hash
+        ON CONFLICT(url) DO UPDATE SET
+          count = count + 1`,
+      },
+      { query: `DELETE FROM moz_places_dupes_temp WHERE count > 1` },
+      { query: `DROP TABLE moz_places_dupes_temp` },
+
+      // MOZ_ANNO_ATTRIBUTES
+      // A.1 remove obsolete annotations from moz_annos.
+      // The 'weave0' idiom exploits character ordering (0 follows /) to
+      // efficiently select all annos with a 'weave/' prefix.
+      {
+        query: `DELETE FROM moz_annos
+        WHERE type = 4 OR anno_attribute_id IN (
+          SELECT id FROM moz_anno_attributes
+          WHERE name = 'downloads/destinationFileName' OR
+                name BETWEEN 'weave/' AND 'weave0'
+        )`,
+      },
+
+      // A.3 remove unused attributes.
+      {
+        query: `DELETE FROM moz_anno_attributes WHERE id IN (
+          SELECT id FROM moz_anno_attributes n
+          WHERE NOT EXISTS
+              (SELECT id FROM moz_annos WHERE anno_attribute_id = n.id LIMIT 1)
+        )`,
+      },
+
+      // MOZ_ANNOS
+      // B.1 remove annos with an invalid attribute
+      {
+        query: `DELETE FROM moz_annos WHERE id IN (
+          SELECT id FROM moz_annos a
+          WHERE NOT EXISTS
+            (SELECT id FROM moz_anno_attributes
+              WHERE id = a.anno_attribute_id LIMIT 1)
+        )`,
+      },
+
+      // B.2 remove orphan annos
+      {
+        query: `DELETE FROM moz_annos WHERE id IN (
+          SELECT id FROM moz_annos a
+          WHERE NOT EXISTS
+            (SELECT id FROM moz_places WHERE id = a.place_id LIMIT 1)
+        )`,
+      },
+
+      // D.1 remove items that are not uri bookmarks from tag containers
+      {
+        query: `DELETE FROM moz_bookmarks WHERE guid NOT IN (
+          :rootGuid, :menuGuid, :toolbarGuid, :unfiledGuid, :tagsGuid  /* skip roots */
+        ) AND id IN (
+          SELECT b.id FROM moz_bookmarks b
+          WHERE b.parent IN
+            (SELECT id FROM moz_bookmarks WHERE parent = :tags_folder)
+            AND b.type <> :bookmark_type
+        )`,
+        params: {
+          tags_folder: lazy.PlacesUtils.tagsFolderId,
+          bookmark_type: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          rootGuid: lazy.PlacesUtils.bookmarks.rootGuid,
+          menuGuid: lazy.PlacesUtils.bookmarks.menuGuid,
+          toolbarGuid: lazy.PlacesUtils.bookmarks.toolbarGuid,
+          unfiledGuid: lazy.PlacesUtils.bookmarks.unfiledGuid,
+          tagsGuid: lazy.PlacesUtils.bookmarks.tagsGuid,
+        },
+      },
+
+      // D.2 remove empty tags
+      {
+        query: `DELETE FROM moz_bookmarks WHERE guid NOT IN (
+          :rootGuid, :menuGuid, :toolbarGuid, :unfiledGuid, :tagsGuid  /* skip roots */
+        ) AND id IN (
+          SELECT b.id FROM moz_bookmarks b
+          WHERE b.id IN
+            (SELECT id FROM moz_bookmarks WHERE parent = :tags_folder)
+            AND NOT EXISTS
+              (SELECT id from moz_bookmarks WHERE parent = b.id LIMIT 1)
+        )`,
+        params: {
+          tags_folder: lazy.PlacesUtils.tagsFolderId,
+          rootGuid: lazy.PlacesUtils.bookmarks.rootGuid,
+          menuGuid: lazy.PlacesUtils.bookmarks.menuGuid,
+          toolbarGuid: lazy.PlacesUtils.bookmarks.toolbarGuid,
+          unfiledGuid: lazy.PlacesUtils.bookmarks.unfiledGuid,
+          tagsGuid: lazy.PlacesUtils.bookmarks.tagsGuid,
+        },
+      },
+
+      // D.3 move orphan items to unsorted folder
+      {
+        query: `UPDATE moz_bookmarks SET
+          parent = (SELECT id FROM moz_bookmarks WHERE guid = :unfiledGuid)
+        WHERE guid NOT IN (
+          :rootGuid, :menuGuid, :toolbarGuid, :unfiledGuid, :tagsGuid  /* skip roots */
+        ) AND id IN (
+          SELECT b.id FROM moz_bookmarks b
+          WHERE NOT EXISTS
+            (SELECT id FROM moz_bookmarks WHERE id = b.parent LIMIT 1)
+        )`,
+        params: {
+          rootGuid: lazy.PlacesUtils.bookmarks.rootGuid,
+          menuGuid: lazy.PlacesUtils.bookmarks.menuGuid,
+          toolbarGuid: lazy.PlacesUtils.bookmarks.toolbarGuid,
+          unfiledGuid: lazy.PlacesUtils.bookmarks.unfiledGuid,
+          tagsGuid: lazy.PlacesUtils.bookmarks.tagsGuid,
+        },
+      },
+
+      // D.4 Insert tombstones for any synced items with the wrong type.
+      // Sync doesn't support changing the type of an existing item while
+      // keeping its GUID. To avoid confusing other clients, we insert
+      // tombstones for all synced items with the wrong type, so that we
+      // can reupload them with the correct type and a new GUID.
+      {
+        query: `INSERT OR IGNORE INTO moz_bookmarks_deleted(guid, dateRemoved)
+                SELECT guid, :dateRemoved
+                FROM moz_bookmarks
+                WHERE syncStatus <> :syncStatus AND
+                      ((type IN (:folder_type, :separator_type) AND
+                        fk NOTNULL) OR
+                       (type = :bookmark_type AND
+                        fk IS NULL) OR
+                       type IS NULL)`,
+        params: {
+          dateRemoved: lazy.PlacesUtils.toPRTime(new Date()),
+          syncStatus: lazy.PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+          bookmark_type: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          folder_type: lazy.PlacesUtils.bookmarks.TYPE_FOLDER,
+          separator_type: lazy.PlacesUtils.bookmarks.TYPE_SEPARATOR,
+        },
+      },
+
+      // D.5 fix wrong item types
+      // Folders and separators should not have an fk.
+      // If they have a valid fk, convert them to bookmarks, and give them new
+      // GUIDs. If the item has children, we'll move them to the unfiled root
+      // in D.8. If the `fk` doesn't exist in `moz_places`, we'll remove the
+      // item in D.9.
+      {
+        query: `UPDATE moz_bookmarks
+        SET guid = GENERATE_GUID(),
+            type = :bookmark_type
+        WHERE guid NOT IN (
+          :rootGuid, :menuGuid, :toolbarGuid, :unfiledGuid, :tagsGuid  /* skip roots */
+        ) AND id IN (
+          SELECT id FROM moz_bookmarks b
+          WHERE type IN (:folder_type, :separator_type)
+            AND fk NOTNULL
+        )`,
+        params: {
+          bookmark_type: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          folder_type: lazy.PlacesUtils.bookmarks.TYPE_FOLDER,
+          separator_type: lazy.PlacesUtils.bookmarks.TYPE_SEPARATOR,
+          rootGuid: lazy.PlacesUtils.bookmarks.rootGuid,
+          menuGuid: lazy.PlacesUtils.bookmarks.menuGuid,
+          toolbarGuid: lazy.PlacesUtils.bookmarks.toolbarGuid,
+          unfiledGuid: lazy.PlacesUtils.bookmarks.unfiledGuid,
+          tagsGuid: lazy.PlacesUtils.bookmarks.tagsGuid,
+        },
+      },
+
+      // D.6 fix wrong item types
+      // Bookmarks should have an fk, if they don't have any, convert them to
+      // folders.
+      {
+        query: `UPDATE moz_bookmarks
+        SET guid = GENERATE_GUID(),
+            type = :folder_type
+        WHERE guid NOT IN (
+          :rootGuid, :menuGuid, :toolbarGuid, :unfiledGuid, :tagsGuid  /* skip roots */
+        ) AND id IN (
+          SELECT id FROM moz_bookmarks b
+          WHERE type = :bookmark_type
+            AND fk IS NULL
+        )`,
+        params: {
+          bookmark_type: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          folder_type: lazy.PlacesUtils.bookmarks.TYPE_FOLDER,
+          rootGuid: lazy.PlacesUtils.bookmarks.rootGuid,
+          menuGuid: lazy.PlacesUtils.bookmarks.menuGuid,
+          toolbarGuid: lazy.PlacesUtils.bookmarks.toolbarGuid,
+          unfiledGuid: lazy.PlacesUtils.bookmarks.unfiledGuid,
+          tagsGuid: lazy.PlacesUtils.bookmarks.tagsGuid,
+        },
+      },
+
+      // D.7 fix wrong item types
+      // `moz_bookmarks.type` doesn't have a NOT NULL constraint, so it's
+      // possible for an item to not have a type (bug 1586427).
+      {
+        query: `UPDATE moz_bookmarks
+        SET guid = GENERATE_GUID(),
+            type = CASE WHEN fk NOT NULL THEN :bookmark_type ELSE :folder_type END
+        WHERE guid NOT IN (
+         :rootGuid, :menuGuid, :toolbarGuid, :unfiledGuid, :tagsGuid  /* skip roots */
+        ) AND type IS NULL`,
+        params: {
+          bookmark_type: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          folder_type: lazy.PlacesUtils.bookmarks.TYPE_FOLDER,
+          rootGuid: lazy.PlacesUtils.bookmarks.rootGuid,
+          menuGuid: lazy.PlacesUtils.bookmarks.menuGuid,
+          toolbarGuid: lazy.PlacesUtils.bookmarks.toolbarGuid,
+          unfiledGuid: lazy.PlacesUtils.bookmarks.unfiledGuid,
+          tagsGuid: lazy.PlacesUtils.bookmarks.tagsGuid,
+        },
+      },
+
+      // D.8 fix wrong parents
+      // Items cannot have separators or other bookmarks
+      // as parent, if they have bad parent move them to unsorted bookmarks.
+      {
+        query: `UPDATE moz_bookmarks SET
+          parent = (SELECT id FROM moz_bookmarks WHERE guid = :unfiledGuid)
+        WHERE guid NOT IN (
+          :rootGuid, :menuGuid, :toolbarGuid, :unfiledGuid, :tagsGuid  /* skip roots */
+        ) AND id IN (
+          SELECT id FROM moz_bookmarks b
+          WHERE EXISTS
+            (SELECT id FROM moz_bookmarks WHERE id = b.parent
+              AND type IN (:bookmark_type, :separator_type)
+              LIMIT 1)
+        )`,
+        params: {
+          bookmark_type: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          separator_type: lazy.PlacesUtils.bookmarks.TYPE_SEPARATOR,
+          rootGuid: lazy.PlacesUtils.bookmarks.rootGuid,
+          menuGuid: lazy.PlacesUtils.bookmarks.menuGuid,
+          toolbarGuid: lazy.PlacesUtils.bookmarks.toolbarGuid,
+          unfiledGuid: lazy.PlacesUtils.bookmarks.unfiledGuid,
+          tagsGuid: lazy.PlacesUtils.bookmarks.tagsGuid,
+        },
+      },
+
+      // D.9 remove items without a valid place
+      // We've already converted folders with an `fk` to bookmarks in D.5,
+      // and bookmarks without an `fk` to folders in D.6. However, the `fk`
+      // might not reference an existing `moz_places.id`, even if it's
+      // NOT NULL. This statement takes care of those.
+      {
+        query: `DELETE FROM moz_bookmarks AS b
+        WHERE b.guid NOT IN (
+          :rootGuid, :menuGuid, :toolbarGuid, :unfiledGuid, :tagsGuid  /* skip roots */
+        ) AND b.fk NOT NULL
+          AND b.type = :bookmark_type
+          AND NOT EXISTS (SELECT 1 FROM moz_places h WHERE h.id = b.fk)`,
+        params: {
+          bookmark_type: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          rootGuid: lazy.PlacesUtils.bookmarks.rootGuid,
+          menuGuid: lazy.PlacesUtils.bookmarks.menuGuid,
+          toolbarGuid: lazy.PlacesUtils.bookmarks.toolbarGuid,
+          unfiledGuid: lazy.PlacesUtils.bookmarks.unfiledGuid,
+          tagsGuid: lazy.PlacesUtils.bookmarks.tagsGuid,
+        },
+      },
+
+      // D.10 fix non-consecutive positions.
+      {
+        query: `
+          WITH positions(item_id, pos, seq) AS (
+            SELECT id, position AS pos,
+                   (row_number() OVER (PARTITION BY parent ORDER BY position)) - 1 AS seq
+            FROM moz_bookmarks
+          )
+          UPDATE moz_bookmarks
+          SET position = seq
+          FROM positions
+          WHERE item_id = moz_bookmarks.id AND seq <> pos`,
+      },
+
+      // D.12 Fix empty-named tags.
+      // Tags were allowed to have empty names due to a UI bug.  Fix them by
+      // replacing their title with "(notitle)", and bumping the change counter
+      // for all bookmarks with the fixed tags.
+      {
+        query: `UPDATE moz_bookmarks SET syncChangeCounter = syncChangeCounter + 1
+         WHERE fk IN (SELECT b.fk FROM moz_bookmarks b
+                      JOIN moz_bookmarks p ON p.id = b.parent
+                      WHERE length(p.title) = 0 AND p.type = :folder_type AND
+                            p.parent = :tags_folder)`,
+        params: {
+          folder_type: lazy.PlacesUtils.bookmarks.TYPE_FOLDER,
+          tags_folder: lazy.PlacesUtils.tagsFolderId,
+        },
+      },
+      {
+        query: `UPDATE moz_bookmarks SET title = :empty_title
+        WHERE length(title) = 0 AND type = :folder_type
+          AND parent = :tags_folder`,
+        params: {
+          empty_title: "(notitle)",
+          folder_type: lazy.PlacesUtils.bookmarks.TYPE_FOLDER,
+          tags_folder: lazy.PlacesUtils.tagsFolderId,
+        },
+      },
+
+      // MOZ_ICONS
+      // E.1 remove orphan icon entries.
+      {
+        query: `DELETE FROM moz_pages_w_icons WHERE page_url_hash NOT IN (
+          SELECT url_hash FROM moz_places
+        )`,
+      },
+
+      // Remove icons whose origin is not in moz_origins, unless referenced.
+      {
+        query: `DELETE FROM moz_icons WHERE id IN (
+          SELECT id FROM moz_icons WHERE root = 0
+          UNION ALL
+          SELECT id FROM moz_icons
+          WHERE root = 1
+            AND get_host_and_port(icon_url) NOT IN (SELECT host FROM moz_origins)
+            AND fixup_url(get_host_and_port(icon_url)) NOT IN (SELECT host FROM moz_origins)
+          EXCEPT
+          SELECT icon_id FROM moz_icons_to_pages
+        )`,
+      },
+
+      // MOZ_HISTORYVISITS
+      // F.1 remove orphan visits
+      {
+        query: `DELETE FROM moz_historyvisits WHERE id IN (
+          SELECT id FROM moz_historyvisits v
+          WHERE NOT EXISTS
+            (SELECT id FROM moz_places WHERE id = v.place_id LIMIT 1)
+        )`,
+      },
+
+      // MOZ_INPUTHISTORY
+      // G.1 remove orphan input history
+      {
+        query: `DELETE FROM moz_inputhistory WHERE place_id IN (
+          SELECT place_id FROM moz_inputhistory i
+          WHERE NOT EXISTS
+            (SELECT id FROM moz_places WHERE id = i.place_id LIMIT 1)
+        )`,
+      },
+
+      // MOZ_KEYWORDS
+      // I.1 remove unused keywords
+      {
+        query: `DELETE FROM moz_keywords WHERE id IN (
+          SELECT id FROM moz_keywords k
+          WHERE NOT EXISTS
+            (SELECT 1 FROM moz_places h WHERE k.place_id = h.id)
+        )`,
+      },
+
+      // MOZ_PLACES
+      // L.2 recalculate visit_count and last_visit_date
+      {
+        query: `UPDATE moz_places
+        SET visit_count = (SELECT count(*) FROM moz_historyvisits
+                            WHERE place_id = moz_places.id AND visit_type NOT IN (0,4,7,8,9)),
+            last_visit_date = (SELECT MAX(visit_date) FROM moz_historyvisits
+                                WHERE place_id = moz_places.id)
+        WHERE id IN (
+          SELECT h.id FROM moz_places h
+          WHERE visit_count <> (SELECT count(*) FROM moz_historyvisits v
+                                WHERE v.place_id = h.id AND visit_type NOT IN (0,4,7,8,9))
+              OR last_visit_date IS NOT
+                (SELECT MAX(visit_date) FROM moz_historyvisits v WHERE v.place_id = h.id)
+        )`,
+      },
+
+      // L.3 recalculate hidden for redirects.
+      {
+        query: `UPDATE moz_places
+        SET hidden = 1
+        WHERE id IN (
+          SELECT h.id FROM moz_places h
+          JOIN moz_historyvisits src ON src.place_id = h.id
+          JOIN moz_historyvisits dst ON dst.from_visit = src.id AND dst.visit_type IN (5,6)
+          LEFT JOIN moz_bookmarks on fk = h.id AND fk ISNULL
+          GROUP BY src.place_id HAVING count(*) = visit_count
+        )`,
+      },
+
+      // L.4 recalculate foreign_count.
+      {
+        query: `UPDATE moz_places SET foreign_count =
+          (SELECT count(*) FROM moz_bookmarks WHERE fk = moz_places.id ) +
+          (SELECT count(*) FROM moz_keywords WHERE place_id = moz_places.id )`,
+      },
+
+      // L.5 recalculate missing hashes.
+      {
+        query: `UPDATE moz_places SET url_hash = hash(url) WHERE url_hash = 0`,
+      },
+
+      // L.6 fix invalid Place GUIDs.
+      {
+        query: `UPDATE moz_places
+        SET guid = GENERATE_GUID()
+        WHERE guid IS NULL OR
+              NOT IS_VALID_GUID(guid)`,
+      },
+
+      // MOZ_BOOKMARKS
+      // S.1 fix invalid GUIDs for synced bookmarks.
+      // This requires multiple related statements.
+      // First, we insert tombstones for all synced bookmarks with invalid
+      // GUIDs, so that we can delete them on the server. Second, we add a
+      // temporary trigger to bump the change counter for the parents of any
+      // items we update, since Sync stores the list of child GUIDs on the
+      // parent. Finally, we assign new GUIDs for all items with missing and
+      // invalid GUIDs, bump their change counters, and reset their sync
+      // statuses to NEW so that they're considered for deduping.
+      {
+        query: `INSERT OR IGNORE INTO moz_bookmarks_deleted(guid, dateRemoved)
+        SELECT guid, :dateRemoved
+        FROM moz_bookmarks
+        WHERE syncStatus <> :syncStatus AND
+              guid NOT NULL AND
+              NOT IS_VALID_GUID(guid)`,
+        params: {
+          dateRemoved: lazy.PlacesUtils.toPRTime(new Date()),
+          syncStatus: lazy.PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+        },
+      },
+      {
+        query: `UPDATE moz_bookmarks
+        SET guid = GENERATE_GUID(),
+            syncStatus = :syncStatus
+        WHERE guid IS NULL OR
+              NOT IS_VALID_GUID(guid)`,
+        params: {
+          syncStatus: lazy.PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+        },
+      },
+
+      // S.2 drop tombstones for bookmarks that aren't deleted.
+      {
+        query: `DELETE FROM moz_bookmarks_deleted
+        WHERE guid IN (SELECT guid FROM moz_bookmarks)`,
+      },
+
+      // S.3 set missing added and last modified dates.
+      {
+        query: `UPDATE moz_bookmarks
+        SET dateAdded = COALESCE(NULLIF(dateAdded, 0), NULLIF(lastModified, 0), NULLIF((
+              SELECT MIN(visit_date) FROM moz_historyvisits
+              WHERE place_id = fk
+            ), 0), STRFTIME('%s', 'now', 'localtime', 'utc') * 1000000),
+            lastModified = COALESCE(NULLIF(lastModified, 0), NULLIF(dateAdded, 0), NULLIF((
+              SELECT MAX(visit_date) FROM moz_historyvisits
+              WHERE place_id = fk
+            ), 0), STRFTIME('%s', 'now', 'localtime', 'utc') * 1000000)
+        WHERE NULLIF(dateAdded, 0) IS NULL OR
+              NULLIF(lastModified, 0) IS NULL`,
+      },
+
+      // S.4 reset added dates that are ahead of last modified dates.
+      {
+        query: `UPDATE moz_bookmarks
+         SET dateAdded = lastModified
+         WHERE dateAdded > lastModified`,
+      },
+    ];
+
+    // Create triggers for updating Sync metadata. The "sync change" trigger
+    // bumps the parent's change counter when we update a GUID or move an item
+    // to a different folder, since Sync stores the list of child GUIDs on the
+    // parent. The "sync tombstone" trigger inserts tombstones for deleted
+    // synced bookmarks.
+    cleanupStatements.unshift({
+      query: `CREATE TEMP TRIGGER IF NOT EXISTS moz_bm_sync_change_temp_trigger
+      AFTER UPDATE OF guid, parent, position ON moz_bookmarks
+      FOR EACH ROW
+      BEGIN
+        UPDATE moz_bookmarks
+        SET syncChangeCounter = syncChangeCounter + 1
+        WHERE id IN (OLD.parent, NEW.parent, NEW.id);
+      END`,
+    });
+    cleanupStatements.unshift({
+      query: `CREATE TEMP TRIGGER IF NOT EXISTS moz_bm_sync_tombstone_temp_trigger
+      AFTER DELETE ON moz_bookmarks
+      FOR EACH ROW WHEN OLD.guid NOT NULL AND
+                        OLD.syncStatus <> 1
+      BEGIN
+        UPDATE moz_bookmarks
+        SET syncChangeCounter = syncChangeCounter + 1
+        WHERE id = OLD.parent;
+
+        INSERT INTO moz_bookmarks_deleted(guid, dateRemoved)
+        VALUES(OLD.guid, STRFTIME('%s', 'now', 'localtime', 'utc') * 1000000);
+      END`,
+    });
+    cleanupStatements.push({
+      query: `DROP TRIGGER moz_bm_sync_change_temp_trigger`,
+    });
+    cleanupStatements.push({
+      query: `DROP TRIGGER moz_bm_sync_tombstone_temp_trigger`,
+    });
+
+    return cleanupStatements;
+  },
+
+  /**
+   * Tries to vacuum the database.
+   *
+   * Note: although this function isn't actually async, we keep it async to
+   * allow us to maintain a simple, consistent API for the tasks within this object.
+   *
+   * @return {Promise} resolves when database is vacuumed.
+   * @resolves to an array of logs for this task.
+   * @rejects if we are unable to vacuum database.
+   */
+  async vacuum() {
+    let logs = [];
+    let placesDbPath = PathUtils.join(PathUtils.profileDir, "places.sqlite");
+    let info = await IOUtils.stat(placesDbPath);
+    logs.push(`Initial database size is ${parseInt(info.size / 1024)}KiB`);
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "PlacesDBUtils: vacuum",
+      async db => {
+        await db.execute("VACUUM");
+        logs.push("The database has been vacuumed");
+        info = await IOUtils.stat(placesDbPath);
+        logs.push(`Final database size is ${parseInt(info.size / 1024)}KiB`);
+        return logs;
+      }
+    ).catch(() => {
+      PlacesDBUtils.clearPendingTasks();
+      throw new Error("Unable to vacuum database");
+    });
+  },
+
+  /**
+   * Forces a full expiration on the database.
+   *
+   * Note: although this function isn't actually async, we keep it async to
+   * allow us to maintain a simple, consistent API for the tasks within this object.
+   *
+   * @return {Promise} resolves when the database in cleaned up.
+   * @resolves to an array of logs for this task.
+   */
+  async expire() {
+    let logs = [];
+
+    let expiration = Cc["@mozilla.org/places/expiration;1"].getService(
+      Ci.nsIObserver
+    );
+
+    let returnPromise = new Promise(res => {
+      let observer = (subject, topic, data) => {
+        Services.obs.removeObserver(observer, topic);
+        logs.push("Database cleaned up");
+        res(logs);
+      };
+      Services.obs.addObserver(
+        observer,
+        lazy.PlacesUtils.TOPIC_EXPIRATION_FINISHED
+      );
+    });
+
+    // Force an orphans expiration step.
+    expiration.observe(null, "places-debug-start-expiration", 0);
+    return returnPromise;
+  },
+
+  /**
+   * Collects statistical data on the database.
+   *
+   * @return {Promise} resolves when statistics are collected.
+   * @resolves to an array of logs for this task.
+   * @rejects if we are unable to collect stats for some reason.
+   */
+  async stats() {
+    let logs = [];
+    let placesDbPath = PathUtils.join(PathUtils.profileDir, "places.sqlite");
+    let info = await IOUtils.stat(placesDbPath);
+    logs.push(`Places.sqlite size is ${parseInt(info.size / 1024)}KiB`);
+    let faviconsDbPath = PathUtils.join(
+      PathUtils.profileDir,
+      "favicons.sqlite"
+    );
+    info = await IOUtils.stat(faviconsDbPath);
+    logs.push(`Favicons.sqlite size is ${parseInt(info.size / 1024)}KiB`);
+
+    // Execute each step async.
+    let pragmas = [
+      "user_version",
+      "page_size",
+      "cache_size",
+      "journal_mode",
+      "synchronous",
+    ].map(p => `pragma_${p}`);
+    let pragmaQuery = `SELECT * FROM ${pragmas.join(", ")}`;
+    await lazy.PlacesUtils.withConnectionWrapper(
+      "PlacesDBUtils: pragma for stats",
+      async db => {
+        let row = (await db.execute(pragmaQuery))[0];
+        for (let i = 0; i != pragmas.length; i++) {
+          logs.push(`${pragmas[i]} is ${row.getResultByIndex(i)}`);
+        }
+      }
+    ).catch(() => {
+      logs.push("Could not set pragma for stat collection");
+    });
+
+    // Get maximum number of unique URIs.
+    try {
+      let limitURIs = await Cc["@mozilla.org/places/expiration;1"]
+        .getService(Ci.nsISupports)
+        .wrappedJSObject.getPagesLimit();
+      logs.push(
+        "History can store a maximum of " + limitURIs + " unique pages"
+      );
+    } catch (ex) {}
+
+    let query = "SELECT name FROM sqlite_master WHERE type = :type";
+    let params = {};
+    let _getTableCount = async tableName => {
+      let db = await lazy.PlacesUtils.promiseDBConnection();
+      let rows = await db.execute(`SELECT count(*) FROM ${tableName}`);
+      logs.push(
+        `Table ${tableName} has ${rows[0].getResultByIndex(0)} records`
+      );
+    };
+
+    try {
+      params.type = "table";
+      let db = await lazy.PlacesUtils.promiseDBConnection();
+      await db.execute(query, params, r =>
+        _getTableCount(r.getResultByIndex(0))
+      );
+    } catch (ex) {
+      throw new Error("Unable to collect stats.");
+    }
+
+    let details = await PlacesDBUtils.getEntitiesStats();
+    logs.push(
+      `Pages sequentiality: ${details.get("moz_places").sequentialityPerc}`
+    );
+    let entities = Array.from(details.keys()).sort((a, b) => {
+      return details.get(a).sizePerc - details.get(b).sizePerc;
+    });
+    for (let key of entities) {
+      let info = details.get(key);
+      logs.push(
+        `${key}: ${info.sizeBytes / 1024}KiB (${info.sizePerc}%), ${
+          info.efficiencyPerc
+        }% eff.`
+      );
+    }
+
+    return logs;
+  },
+
+  /**
+   * Recalculates statistical data on the origin frecencies in the database.
+   *
+   * @return {Promise} resolves when statistics are collected.
+   */
+  originFrecencyStats() {
+    return new Promise(resolve => {
+      lazy.PlacesUtils.history.recalculateOriginFrecencyStats(() =>
+        resolve(["Recalculated origin frecency stats"])
+      );
+    });
+  },
+
+  /**
+   * Collects telemetry data and reports it to Telemetry.
+   *
+   * Note: although this function isn't actually async, we keep it async to
+   * allow us to maintain a simple, consistent API for the tasks within this object.
+   *
+   */
+  async telemetry() {
+    // This will be populated with one integer property for each probe result,
+    // using the histogram name as key.
+    let probeValues = {};
+
+    // The following array contains an ordered list of entries that are
+    // processed to collect telemetry data.  Each entry has these properties:
+    //
+    //  histogram: Name of the telemetry histogram to update.
+    //  query:     This is optional.  If present, contains a database command
+    //             that will be executed asynchronously, and whose result will
+    //             be added to the telemetry histogram.
+    //  callback:  This is optional.  If present, contains a function that must
+    //             return the value that will be added to the telemetry
+    //             histogram. If a query is also present, its result is passed
+    //             as the first argument of the function.  If the function
+    //             raises an exception, no data is added to the histogram.
+    //
+    // Since all queries are executed in order by the database backend, the
+    // callbacks can also use the result of previous queries stored in the
+    // probeValues object.
+    let probes = [
+      {
+        histogram: "PLACES_PAGES_COUNT",
+        query: "SELECT count(*) FROM moz_places",
+      },
+
+      {
+        histogram: "PLACES_BOOKMARKS_COUNT",
+        query: `SELECT count(*) FROM moz_bookmarks b
+                    JOIN moz_bookmarks t ON t.id = b.parent
+                    AND t.parent <> :tags_folder
+                    WHERE b.type = :type_bookmark`,
+        params: {
+          tags_folder: lazy.PlacesUtils.tagsFolderId,
+          type_bookmark: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        },
+      },
+
+      {
+        histogram: "PLACES_TAGS_COUNT",
+        query: `SELECT count(*) FROM moz_bookmarks
+                    WHERE parent = :tags_folder`,
+        params: {
+          tags_folder: lazy.PlacesUtils.tagsFolderId,
+        },
+      },
+
+      {
+        histogram: "PLACES_KEYWORDS_COUNT",
+        query: "SELECT count(*) FROM moz_keywords",
+      },
+
+      {
+        histogram: "PLACES_SORTED_BOOKMARKS_PERC",
+        query: `SELECT IFNULL(ROUND((
+                      SELECT count(*) FROM moz_bookmarks b
+                      JOIN moz_bookmarks p ON p.id = b.parent
+                      JOIN moz_bookmarks g ON g.id = p.parent
+                      WHERE g.guid <> :root_guid
+                        AND g.guid <> :tags_guid
+                        AND b.type  = :type_bookmark
+                      ) * 100 / (
+                      SELECT count(*) FROM moz_bookmarks b
+                      JOIN moz_bookmarks p ON p.id = b.parent
+                      JOIN moz_bookmarks g ON g.id = p.parent
+                      AND g.guid <> :tags_guid
+                      WHERE b.type = :type_bookmark
+                    )), 0)`,
+        params: {
+          root_guid: lazy.PlacesUtils.bookmarks.rootGuid,
+          tags_guid: lazy.PlacesUtils.bookmarks.tagsGuid,
+          type_bookmark: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        },
+      },
+
+      {
+        histogram: "PLACES_TAGGED_BOOKMARKS_PERC",
+        query: `SELECT IFNULL(ROUND((
+                      SELECT count(*) FROM moz_bookmarks b
+                      JOIN moz_bookmarks t ON t.id = b.parent
+                      AND t.parent = :tags_folder
+                      ) * 100 / (
+                      SELECT count(*) FROM moz_bookmarks b
+                      JOIN moz_bookmarks t ON t.id = b.parent
+                      AND t.parent <> :tags_folder
+                      WHERE b.type = :type_bookmark
+                    )), 0)`,
+        params: {
+          tags_folder: lazy.PlacesUtils.tagsFolderId,
+          type_bookmark: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        },
+      },
+
+      {
+        histogram: "PLACES_DATABASE_FILESIZE_MB",
+        async callback() {
+          let placesDbPath = PathUtils.join(
+            PathUtils.profileDir,
+            "places.sqlite"
+          );
+          let info = await IOUtils.stat(placesDbPath);
+          return parseInt(info.size / BYTES_PER_MEBIBYTE);
+        },
+      },
+
+      {
+        histogram: "PLACES_DATABASE_FAVICONS_FILESIZE_MB",
+        async callback() {
+          let faviconsDbPath = PathUtils.join(
+            PathUtils.profileDir,
+            "favicons.sqlite"
+          );
+          let info = await IOUtils.stat(faviconsDbPath);
+          return parseInt(info.size / BYTES_PER_MEBIBYTE);
+        },
+      },
+
+      {
+        histogram: "PLACES_ANNOS_PAGES_COUNT",
+        query: "SELECT count(*) FROM moz_annos",
+      },
+
+      {
+        histogram: "PLACES_MAINTENANCE_DAYSFROMLAST",
+        callback() {
+          try {
+            let lastMaintenance = Services.prefs.getIntPref(
+              "places.database.lastMaintenance"
+            );
+            let nowSeconds = parseInt(Date.now() / 1000);
+            return parseInt((nowSeconds - lastMaintenance) / 86400);
+          } catch (ex) {
+            return 60;
+          }
+        },
+      },
+      {
+        scalar: "places.pages_need_frecency_recalculation",
+        query: "SELECT count(*) FROM moz_places WHERE recalc_frecency = 1",
+      },
+      {
+        scalar: "places.previousday_visits",
+        query: `SELECT COUNT(*) from moz_places
+                      WHERE hidden=0 AND last_visit_date < (strftime('%s', 'now', 'start of day') * 1000000)
+                      AND last_visit_date > (strftime('%s', 'now', 'start of day', '-1 day') * 1000000)
+                      AND last_visit_date IS NOT NULL;`,
+      },
+    ];
+
+    for (let probe of probes) {
+      let val;
+      if ("query" in probe) {
+        let db = await lazy.PlacesUtils.promiseDBConnection();
+        val = (
+          await db.execute(probe.query, probe.params || {})
+        )[0].getResultByIndex(0);
+      }
+      // Report the result of the probe through Telemetry.
+      // The resulting promise cannot reject.
+      if ("callback" in probe) {
+        val = await probe.callback(val);
+      }
+      probeValues[probe.histogram || probe.scalar] = val;
+      if (probe.histogram) {
+        Services.telemetry.getHistogramById(probe.histogram).add(val);
+      } else if (probe.scalar) {
+        Services.telemetry.scalarSet(probe.scalar, val);
+      } else {
+        throw new Error("Unknwon telemetry probe type");
+      }
+    }
+  },
+
+  /**
+   * Remove old and useless places.sqlite.corrupt files.
+   *
+   * @resolves to an array of logs for this task.
+   *
+   */
+  async removeOldCorruptDBs() {
+    let logs = [];
+    logs.push(
+      "> Cleanup profile from places.sqlite.corrupt files older than " +
+        CORRUPT_DB_RETAIN_DAYS +
+        " days."
+    );
+    let re = /places\.sqlite(-\d)?\.corrupt$/;
+    let currentTime = Date.now();
+    let children = await IOUtils.getChildren(PathUtils.profileDir);
+    try {
+      for (let entry of children) {
+        let fileInfo = await IOUtils.stat(entry);
+        let lastModificationDate;
+        if (fileInfo.type == "regular" && re.test(entry)) {
+          lastModificationDate = fileInfo.lastModified;
+          try {
+            // Convert milliseconds to days.
+            let days = Math.ceil(
+              (currentTime - lastModificationDate) / MS_PER_DAY
+            );
+            if (days >= CORRUPT_DB_RETAIN_DAYS || days < 0) {
+              await IOUtils.remove(entry);
+            }
+          } catch (error) {
+            logs.push("Could not remove file: " + entry, error);
+          }
+        }
+      }
+    } catch (error) {
+      logs.push("removeOldCorruptDBs failed", error);
+    }
+    return logs;
+  },
+
+  /**
+   * Gets detailed statistics about database entities like tables and indices.
+   * @returns {Map} a Map by table name, containing an object with the following
+   *          properties:
+   *            - efficiencyPerc: percentage filling of pages, an high
+   *              efficiency means most pages are filled up almost completely.
+   *              This value is not particularly useful with a low number of
+   *              pages.
+   *            - sizeBytes: size of the entity in bytes
+   *            - pages: number of pages of the entity
+   *            - sizePerc: percentage of the total database size
+   *            - sequentialityPerc: percentage of sequential pages, this is
+   *              a global value of the database, thus it's the same for every
+   *              entity, and it can be used to evaluate fragmentation and the
+   *              need for vacuum.
+   */
+  async getEntitiesStats() {
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    let rows = await db.execute(`
+      /* do not warn (bug no): no need for index */
+      SELECT name,
+      round((pgsize - unused) * 100.0 / pgsize, 1) as efficiency_perc,
+      pgsize as size_bytes, pageno as pages,
+      round(pgsize * 100.0 / (SELECT sum(pgsize) FROM dbstat WHERE aggregate = TRUE), 1) as size_perc,
+      round((
+        WITH s(row, pageno) AS (
+          SELECT row_number() OVER (ORDER BY path), pageno FROM dbstat ORDER BY path
+        )
+        SELECT sum(s1.pageno+1==s2.pageno)*100.0/count(*)
+        FROM s AS s1, s AS s2
+        WHERE s1.row+1=s2.row
+      ), 1) AS sequentiality_perc
+      FROM dbstat
+      WHERE aggregate = TRUE
+    `);
+    let entitiesByName = new Map();
+    for (let row of rows) {
+      let details = {
+        efficiencyPerc: row.getResultByName("efficiency_perc"),
+        pages: row.getResultByName("pages"),
+        sizeBytes: row.getResultByName("size_bytes"),
+        sizePerc: row.getResultByName("size_perc"),
+        sequentialityPerc: row.getResultByName("sequentiality_perc"),
+      };
+      entitiesByName.set(row.getResultByName("name"), details);
+    }
+    return entitiesByName;
+  },
+
+  /**
+   * Gets detailed statistics about database entities and their respective row
+   * counts.
+   * @returns {Array} An array that augments each object returned by
+   *          {@link getEntitiesStats} with the following extra properties:
+   *            - entity: name of the entity
+   *            - count: row count of the entity
+   */
+  async getEntitiesStatsAndCounts() {
+    let stats = await PlacesDBUtils.getEntitiesStats();
+    let data = [];
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    for (let [entity, value] of stats) {
+      let count = "-";
+      try {
+        if (
+          entity.startsWith("moz_") &&
+          !entity.endsWith("index") &&
+          entity != "moz_places_visitcount" /* bug in index name */
+        ) {
+          count = (
+            await db.execute(`SELECT count(*) FROM ${entity}`)
+          )[0].getResultByIndex(0);
+        }
+      } catch (ex) {
+        console.error(ex);
+      }
+      data.push(Object.assign(value, { entity, count }));
+    }
+    return data;
+  },
+
+  /**
+   * Runs a list of tasks, returning a Map when done.
+   *
+   * @param tasks
+   *        Array of tasks to be executed, in form of pointers to methods in
+   *        this module.
+   * @return {Promise}
+   *        A promise that resolves with a Map[taskName(String) -> Object].
+   *        The Object has the following properties:
+   *         - succeeded: boolean
+   *         - logs: an array of strings containing the messages logged by the task
+   */
+  async runTasks(tasks) {
+    if (!this._registeredShutdownObserver) {
+      this._registeredShutdownObserver = true;
+      lazy.PlacesUtils.registerShutdownFunction(() => {
+        this._isShuttingDown = true;
+      });
+    }
+    PlacesDBUtils._clearTaskQueue = false;
+    let tasksMap = new Map();
+    for (let task of tasks) {
+      if (PlacesDBUtils._isShuttingDown) {
+        tasksMap.set(task.name, {
+          succeeded: false,
+          logs: ["Shutting down, will not schedule the task."],
+        });
+        continue;
+      }
+
+      if (PlacesDBUtils._clearTaskQueue) {
+        tasksMap.set(task.name, {
+          succeeded: false,
+          logs: ["The task queue was cleared by an error in another task."],
+        });
+        continue;
+      }
+
+      let result = await task()
+        .then((logs = [`${task.name} complete`]) => ({ succeeded: true, logs }))
+        .catch(err => ({ succeeded: false, logs: [err.message] }));
+      tasksMap.set(task.name, result);
+    }
+    return tasksMap;
+  },
+};
+
+async function integrity(dbName) {
+  async function check(db) {
+    let row;
+    await db.execute("PRAGMA integrity_check", null, (r, cancel) => {
+      row = r;
+      cancel();
+    });
+    return row.getResultByIndex(0) === "ok";
+  }
+
+  // Create a new connection for this check, so we can operate independently
+  // from a broken Places service.
+  // openConnection returns an exception with .result == Cr.NS_ERROR_FILE_CORRUPTED,
+  // we should do the same everywhere we want maintenance to try replacing the
+  // database on next startup.
+  let path = PathUtils.join(PathUtils.profileDir, dbName);
+  let db = await lazy.Sqlite.openConnection({ path });
+  try {
+    if (await check(db)) {
+      return;
+    }
+
+    // We stopped due to an integrity corruption, try to fix it if possible.
+    // First, try to reindex, this often fixes simple indices problems.
+    try {
+      await db.execute("REINDEX");
+    } catch (ex) {
+      throw new Components.Exception(
+        "Impossible to reindex database",
+        Cr.NS_ERROR_FILE_CORRUPTED
+      );
+    }
+
+    // Check again.
+    if (!(await check(db))) {
+      throw new Components.Exception(
+        "The database is still corrupt",
+        Cr.NS_ERROR_FILE_CORRUPTED
+      );
+    }
+  } finally {
+    await db.close();
+  }
+}
+
+export function PlacesDBUtilsIdleMaintenance() {}
+
+PlacesDBUtilsIdleMaintenance.prototype = {
+  observe(subject, topic, data) {
+    switch (topic) {
+      case "idle-daily":
+        // Once a week run places.sqlite maintenance tasks.
+        let lastMaintenance = Services.prefs.getIntPref(
+          "places.database.lastMaintenance",
+          0
+        );
+        let nowSeconds = parseInt(Date.now() / 1000);
+        if (lastMaintenance < nowSeconds - MAINTENANCE_INTERVAL_SECONDS) {
+          PlacesDBUtils.maintenanceOnIdle();
+        }
+        break;
+      default:
+        throw new Error("Trying to handle an unknown category.");
+    }
+  },
+  classID: Components.ID("d38926e0-29c1-11eb-8588-0800200c9a66"),
+  QueryInterface: ChromeUtils.generateQI(["nsIObserver"]),
+};