gecko-dev/storage/public/mozIStorageService.idl
2012-05-21 12:12:37 +01:00

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/* -*- 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;
/**
* 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.
*/
[scriptable, uuid(fe8e95cb-b377-4c8d-bccb-d9198c67542b)]
interface mozIStorageService : nsISupports {
/**
* Get a connection to a named special database storage.
*
* @param aStorageKey a string key identifying the type of storage
* requested. Valid values include: "profile", "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.
*
* If your database contains virtual tables (f.e. for full-text indexes), you
* must open it with openUnsharedDatabase, as those tables are incompatible
* with a shared cache. If you attempt to use this method to open a database
* containing virtual tables, it will think the database is corrupted and
* throw NS_ERROR_FILE_CORRUPTED.
*
* @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.
*
* Each connection uses its own sqlite cache, which is inefficient, so you
* should use openDatabase instead of this method unless you need a feature
* of SQLite that is incompatible with a shared cache, like virtual table
* and full text indexing support. If cache contention is expected, for
* instance when operating on a database from multiple threads, 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);
/*
* 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"
#define MOZ_STORAGE_PROFILE_STORAGE_KEY "profile"
%}