storage/mozIStorageVacuumParticipant.idl
author Masayuki Nakano <masayuki@d-toybox.com>
Thu, 10 Jan 2019 08:50:41 +0000
changeset 453219 99a977d519a0b78e267d3dce4afb009b8d3be769
parent 244681 ad01543457e739b4eee7a245e16734a3ecfd10ad
permissions -rw-r--r--
Bug 181137 - part 8: Make ContentIteratorBase and its subclasses non-refcountable r=smaug This patch makes ContentIteratorBase, PostContentIterator, PreContentIterator and ContentSubtreeIterator classes non-refcountable because most users can create their instances in stack and such users may be in a hot path. So, we can save a lot of cost of instantiation. Unfortunately, only ScriptableContentIterator creates one of the concrete classes and needs to destroy it properly. Therefore, its EnsureContentIterator(), destructor, traverse and unlink code becomes messy. However, ScriptableContentIterator was designed for automated tests and we need to maintain it not so many times. Therefore, improvement of other users must be worthwhiler than this demerit. Differential Revision: https://phabricator.services.mozilla.com/D15928

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsISupports.idl"

interface mozIStorageConnection;

/**
 * This interface contains the information that the Storage service needs to
 * vacuum a database.  This interface is created as a service through the
 * category manager with the category "vacuum-participant".
 * Please see https://developer.mozilla.org/en/mozIStorageVacuumParticipant for
 * more information.
 */
[scriptable, uuid(8f367508-1d9a-4d3f-be0c-ac11b6dd7dbf)]
interface mozIStorageVacuumParticipant : nsISupports {
  /**
   * The expected page size in bytes for the database.  The vacuum manager will
   * try to correct the page size during idle based on this value.
   *
   * @note If the database is using the WAL journal mode, the page size won't
  *        be changed to the requested value.  See bug 634374.
   * @note Valid page size values are powers of 2 between 512 and 65536.
   *       The suggested value is mozIStorageConnection::defaultPageSize.
   */
  readonly attribute long expectedDatabasePageSize;

  /**
   * Connection to the database file to be vacuumed.
   */
  readonly attribute mozIStorageConnection databaseConnection;

  /**
   * Notifies when a vacuum operation begins.  Listeners should avoid using the
   * database till onEndVacuum is received.
   *
   * @return true to proceed with the vacuum, false if the participant wants to
   *         opt-out for now, it will be retried later.  Useful when participant
   *         is running some other heavy operation that can't be interrupted.
   *
   * @note When a vacuum operation starts or ends it will also dispatch a global
   *       "heavy-io-task" notification through the observer service with the
   *       data argument being either "vacuum-begin" or "vacuum-end".
   */
  boolean onBeginVacuum();

  /**
   * Notifies when a vacuum operation ends.
   *
   * @param aSucceeded
   *        reports if the vacuum succeeded or failed.
   */
  void onEndVacuum(in boolean aSucceeded);
};