storage/mozIStorageService.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: idl; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsISupports.idl"

interface mozIStorageConnection;
interface nsIFile;
interface nsIFileURL;
interface nsIPropertyBag2;
interface nsIVariant;
interface mozIStorageCompletionCallback;

/**
 * The mozIStorageService interface is intended to be implemented by
 * a service that can create storage connections (mozIStorageConnection)
 * to either a well-known profile database or to a specific database file.
 *
 * This is the only way to open a database connection.
 *
 * @note The first reference to mozIStorageService must be made on the main
 * thread.
 */
[scriptable, uuid(07b6b2f5-6d97-47b4-9584-e65bc467fe9e)]
interface mozIStorageService : nsISupports {
  /**
   * Open an asynchronous connection to a database.
   *
   * This method MUST be called from the main thread. The connection object
   * returned by this function is not threadsafe. You MUST use it only from
   * the main thread.
   *
   * If you have more than one connection to a file, you MUST use the EXACT
   * SAME NAME for the file each time, including case. The sqlite code uses
   * a simple string compare to see if there is already a connection. Opening
   * a connection to "Foo.sqlite" and "foo.sqlite" will CORRUPT YOUR DATABASE.
   *
   * @param aDatabaseStore Either a nsIFile representing the file that contains
   * the database or a special string to open a special database. The special
   * string may be:
   * - "memory" to open an in-memory database.
   *
   * @param aOptions A set of options (may be null). Options may contain:
   * - bool shared (defaults to |false|).
   *   -- If |true|, opens the database with a shared-cache. The
   *     shared-cache mode is more memory-efficient when many
   *     connections to the same database are expected, though, the
   *     connections will contend the cache resource. In any cases
   *     where performance matter, working without a shared-cache will
   *     improve concurrency.  @see openUnsharedDatabase
   *
   * - int growthIncrement (defaults to none).
   *   -- Set the growth increment for the main database.  This hints SQLite to
   *      grow the database file by a given chunk size and may reduce
   *      filesystem fragmentation on large databases.
   *      @see mozIStorageConnection::setGrowthIncrement
   *
   * @param aCallback A callback that will receive the result of the operation.
   *  In case of error, it may receive as status:
   *  - NS_ERROR_OUT_OF_MEMORY if allocating a new storage object fails.
   *  - NS_ERROR_FILE_CORRUPTED if the database file is corrupted.
   *  In case of success, it receives as argument the new database
   *  connection, as an instance of |mozIStorageAsyncConnection|.
   *
   * @throws NS_ERROR_INVALID_ARG if |aDatabaseStore| is neither a file nor
   *         one of the special strings understood by this method, or if one of
   *         the options passed through |aOptions| does not have the right type.
   * @throws NS_ERROR_NOT_SAME_THREAD if called from a thread other than the
   *         main thread.
   */
  void openAsyncDatabase(in nsIVariant aDatabaseStore,
                         [optional] in nsIPropertyBag2 aOptions,
                         in mozIStorageCompletionCallback aCallback);
  /**
   * Get a connection to a named special database storage.
   *
   * @param aStorageKey a string key identifying the type of storage
   * requested.  Valid values include: "memory".
   *
   * @see openDatabase for restrictions on how database connections may be
   * used. For the profile database, you should only access it from the main
   * thread since other callers may also have connections.
   *
   * @returns a new mozIStorageConnection for the requested
   * storage database.
   *
   * @throws NS_ERROR_INVALID_ARG if aStorageKey is invalid.
   */
  mozIStorageConnection openSpecialDatabase(in string aStorageKey);

  /**
   * Open a connection to the specified file.
   *
   * Consumers should check mozIStorageConnection::connectionReady to ensure
   * that they can use the database.  If this value is false, it is strongly
   * recommended that the database be backed up with
   * mozIStorageConnection::backupDB so user data is not lost.
   *
   * ==========
   *   DANGER
   * ==========
   *
   * If you have more than one connection to a file, you MUST use the EXACT
   * SAME NAME for the file each time, including case. The sqlite code uses
   * a simple string compare to see if there is already a connection. Opening
   * a connection to "Foo.sqlite" and "foo.sqlite" will CORRUPT YOUR DATABASE.
   *
   * The connection object returned by this function is not threadsafe. You must
   * use it only from the thread you created it from.
   *
   * @param aDatabaseFile
   *        A nsIFile that represents the database that is to be opened..
   *
   * @returns a mozIStorageConnection for the requested database file.
   *
   * @throws NS_ERROR_OUT_OF_MEMORY
   *         If allocating a new storage object fails.
   * @throws NS_ERROR_FILE_CORRUPTED
   *         If the database file is corrupted.
   */
  mozIStorageConnection openDatabase(in nsIFile aDatabaseFile);

  /**
   * Open a connection to the specified file that doesn't share a sqlite cache.
   *
   * Without a shared-cache, each connection uses its own pages cache, which
   * may be memory inefficient with a large number of connections, in such a
   * case so you should use openDatabase instead.  On the other side, if cache
   * contention may be an issue, for instance when concurrency is important to
   * ensure responsiveness, using unshared connections may be a performance win.
   *
   * ==========
   *   DANGER
   * ==========
   *
   * If you have more than one connection to a file, you MUST use the EXACT
   * SAME NAME for the file each time, including case. The sqlite code uses
   * a simple string compare to see if there is already a connection. Opening
   * a connection to "Foo.sqlite" and "foo.sqlite" will CORRUPT YOUR DATABASE.
   *
   * The connection object returned by this function is not threadsafe. You must
   * use it only from the thread you created it from.
   *
   * @param aDatabaseFile
   *        A nsIFile that represents the database that is to be opened.
   *
   * @returns a mozIStorageConnection for the requested database file.
   *
   * @throws NS_ERROR_OUT_OF_MEMORY
   *         If allocating a new storage object fails.
   * @throws NS_ERROR_FILE_CORRUPTED
   *         If the database file is corrupted.
   */
  mozIStorageConnection openUnsharedDatabase(in nsIFile aDatabaseFile);

  /**
   * See openDatabase(). Exactly the same only initialized with a file URL.
   * Custom parameters can be passed to SQLite and VFS implementations through
   * the query part of the URL.
   *
   * @param aURL
   *        A nsIFileURL that represents the database that is to be opened.
   */
  mozIStorageConnection openDatabaseWithFileURL(in nsIFileURL aFileURL);

  /*
   * Utilities
   */

  /**
   * Copies the specified database file to the specified parent directory with
   * the specified file name.  If the parent directory is not specified, it
   * places the backup in the same directory as the current file.  This function
   * ensures that the file being created is unique.
   *
   * @param aDBFile
   *        The database file that will be backed up.
   * @param aBackupFileName
   *        The name of the new backup file to create.
   * @param [optional] aBackupParentDirectory
   *        The directory you'd like the backup file to be placed.
   * @return The nsIFile representing the backup file.
   */
  nsIFile backupDatabaseFile(in nsIFile aDBFile, in AString aBackupFileName,
                             [optional] in nsIFile aBackupParentDirectory);
};

%{C++

#define MOZ_STORAGE_MEMORY_STORAGE_KEY    "memory"

%}