storage/mozIStorageVacuumParticipant.idl

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "nsISupports.idl"
   8
   9 interface mozIStorageConnection;
  10
  11 /**
  12  * This interface contains the information that the Storage service needs to
  13  * vacuum a database.  This interface is created as a service through the
  14  * category manager with the category "vacuum-participant".
  15  * Please see https://developer.mozilla.org/en/mozIStorageVacuumParticipant for
  16  * more information.
  17  */
  18 [scriptable, uuid(8f367508-1d9a-4d3f-be0c-ac11b6dd7dbf)]
  19 interface mozIStorageVacuumParticipant : nsISupports {
  20   /**
  21    * The expected page size in bytes for the database.  The vacuum manager will
  22    * try to correct the page size during idle based on this value.
  23    *
  24    * @note If the database is using the WAL journal mode, the page size won't
  25   *        be changed to the requested value.  See bug 634374.
  26    * @note Valid page size values are powers of 2 between 512 and 65536.
  27    *       The suggested value is mozIStorageConnection::defaultPageSize.
  28    */
  29   readonly attribute long expectedDatabasePageSize;
  30
  31   /**
  32    * Connection to the database file to be vacuumed.
  33    */
  34   readonly attribute mozIStorageConnection databaseConnection;
  35
  36   /**
  37    * Notifies when a vacuum operation begins.  Listeners should avoid using the
  38    * database till onEndVacuum is received.
  39    *
  40    * @return true to proceed with the vacuum, false if the participant wants to
  41    *         opt-out for now, it will be retried later.  Useful when participant
  42    *         is running some other heavy operation that can't be interrupted.
  43    *
  44    * @note When a vacuum operation starts or ends it will also dispatch a global
  45    *       "heavy-io-task" notification through the observer service with the
  46    *       data argument being either "vacuum-begin" or "vacuum-end".
  47    */
  48   boolean onBeginVacuum();
  49
  50   /**
  51    * Notifies when a vacuum operation ends.
  52    *
  53    * @param aSucceeded
  54    *        reports if the vacuum succeeded or failed.
  55    */
  56   void onEndVacuum(in boolean aSucceeded);
  57 };