mozIStorageService.idl
/* -*- 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"
%{C++
#include "nsLiteralString.h"
%}
interface mozIStorageConnection;
interface nsIFile;
interface nsIFileURL;
interface nsIPropertyBag2;
interface nsIVariant;
interface mozIStorageCompletionCallback;
/**
* PRIVACY WARNING
* ===============
*
* Database file names can be exposed through telemetry and in crash reports on
* the https://crash-stats.mozilla.org site, to allow recognizing the affected
* database.
* if your database name may contain privacy sensitive information, e.g. an
* URL origin, you should use openDatabaseWithFileURL and pass an explicit
* TelemetryFilename to it. That name will be used both for telemetry and for
* thread names in crash reports.
* If you have different needs (e.g. using the javascript module or an async
* connection from the main thread) please coordinate with the mozStorage peers.
*/
/**
* 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 the database with default flags in default mode.
*/
const unsigned long OPEN_DEFAULT = 0;
/**
* Open 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.
* When performance matters, working without a shared-cache will
* improve concurrency. @see openUnsharedDatabase
*/
const unsigned long OPEN_SHARED = 1 << 0;
/**
* Open the underlying database in read-only mode.
*/
const unsigned long OPEN_READONLY = 1 << 1;
/**
* Allow simultaneous access to an asynchronous read-only database
* without any file locking.
*
* For synchronous database, the flag has no effect.
*
* Specifying the OPEN_IGNORE_LOCKING_MODE flag will automatically
* turn on the OPEN_READONLY flag.
*/
const unsigned long OPEN_IGNORE_LOCKING_MODE = 1 << 2;
/**
* Allow multi-process access to the database file.
* Normally this option is disabled as exclusive locking performs better
* and provides some protection against third party manipulation of hot
* databases. Note however this option only shows its effects on Unix
* systems because exclusive locking is not yet implemented on Windows.
*/
const unsigned long OPEN_NOT_EXCLUSIVE = 1 << 3;
/**
* All optional connection object features are off.
*/
const unsigned long CONNECTION_DEFAULT = 0;
/**
* Enable Interrupt-method for the synchronous connection object
* returned by openDatabase, openSpecialDatabase, openUnsharedDatabase
* or openDatabaseWithFileURL calls.
*
* When this flag is not set, Interrupt-method of a
* synchronous connection must not be used.
*
* Asynchronous connection is always interruptible and the flag
* does not change anything.
*
* The following are among the potential risks side effects of
* calling the Interrupt-method:
* - new queries started on a different thread after the
* interrupt call, but before its completion, are interrupted as if
* they had been running prior to the interrupt call. Thus thread
* synchronization is necessary.
* - calls to close the database will wait until the interruption
* finishes.
*/
const unsigned long CONNECTION_INTERRUPTIBLE = 1 << 0;
/**
* 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 aOpenFlags
* A set of flags to open the database with optional features.
* See OPEN_* options above.
* For full details, please refer to the documentation of the flags.
*
* @param aConnectionFlags
* A set of flags to enable optional features for the returned
* asynchronous connection object.
* Currently supports CONNECTION_INTERRUPTIBLE flag.
* For full details, please refer to the documentation of the flag.
*
* @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,
in unsigned long aOpenFlags,
in unsigned long aConnectionFlags,
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".
*
* @param aName an optional string identifying the name of the database.
* If omitted, a filename of ":memory:" will be used which results in a
* private in-memory database specific to this connection, making it
* impossible to clone the in-memory database. If you want to be able to
* clone the connection (or otherwise connect to the in-memory database from
* a connection), then you must pick a name that's sufficiently unique within
* the process to not collide with other mozStorage users.
*
* @param [optional] aConnectionFlags
* A set of flags to enable optional features for the returned
* synchronous connection object.
* Currently supports CONNECTION_INTERRUPTIBLE flag.
* For full details, please refer to the documentation of the flag.
*
* @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 ACString aStorageKey,
[optional] in ACString aName,
[optional] in unsigned long aConnectionFlags);
/**
* 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.
* @param [optional] aConnectionFlags
* A set of flags to enable optional features for the returned
* synchronous connection object.
* Currently supports CONNECTION_INTERRUPTIBLE flag.
* For full details, please refer to the documentation of the flag.
*
* @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, [optional] in unsigned long aConnectionFlags);
/**
* 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.
* @param [optional] aConnectionFlags
* A set of flags to enable optional features for the returned
* synchronous connection object.
* Currently supports CONNECTION_INTERRUPTIBLE flag.
* For full details, please refer to the documentation of the flag.
*
* @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, [optional] in unsigned long aConnectionFlags);
/**
* 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.
* @param [optional] aTelemetryFilename
* The name to use for the database in telemetry. Only needed if the
* actual filename can contain sensitive information.
* @param [optional] aConnectionFlags
* A set of flags to enable optional features for the returned
* synchronous connection object.
* Currently supports CONNECTION_INTERRUPTIBLE flag.
* For full details, please refer to the documentation of the flag.
*/
mozIStorageConnection openDatabaseWithFileURL(
in nsIFileURL aFileURL, [optional] in ACString aTelemetryFilename,
[optional] in unsigned long aConnectionFlags);
};
%{C++
constexpr auto kMozStorageMemoryStorageKey = "memory"_ns;
%}
