summaryrefslogtreecommitdiffstats
path: root/storage/mozIStorageAsyncConnection.idl
blob: 7fca212dca35609cd05b53810c14e5834221a7f3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
/* -*- 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 mozIStorageCompletionCallback;
interface mozIStorageFunction;
interface mozIStorageProgressHandler;
interface mozIStorageBaseStatement;
interface mozIStorageStatement;
interface mozIStorageAsyncStatement;
interface mozIStorageStatementCallback;
interface mozIStoragePendingStatement;
interface nsIFile;

/**
 * mozIStorageAsyncConnection represents an asynchronous database
 * connection attached to a specific file or to an in-memory data
 * storage.  It is the primary interface for interacting with a
 * database from the main thread, including creating prepared
 * statements, executing SQL, and examining database errors.
 */
[scriptable, uuid(8bfd34d5-4ddf-4e4b-89dd-9b14f33534c6)]
interface mozIStorageAsyncConnection : nsISupports {
  /**
   * Transaction behavior constants.
   */
  const int32_t TRANSACTION_DEFAULT = -1;
  const int32_t TRANSACTION_DEFERRED = 0;
  const int32_t TRANSACTION_IMMEDIATE = 1;
  const int32_t TRANSACTION_EXCLUSIVE = 2;

  /**
   * The default behavior for all transactions run on this connection. Defaults
   * to `TRANSACTION_DEFERRED`, and can be overridden for individual
   * transactions.
   */
  attribute int32_t defaultTransactionType;

  /**
   * The maximum number of bound parameters for statements executed on this
   * connection. If your statement has more params than this limit, you'll
   * need to chunk them into multiple statements. See `PlacesUtils.chunkArray`
   * and its callers in Places for examples of how to do this, or read on for
   * an overview.
   *
   * Keep in mind that the variable limit is for the _total_ number of
   * parameters, including ones bound by name (using the `:VVV`, `@VVV`, or
   * `?VVV` syntax) and index (`?` and `?NNN`).
   *
   * This means, when chunking:
   *
   * - If you're binding 1 param per 1 value per chunk (for example, if you
   *   have a list of GUIDs and a clause like `WHERE guid IN (?, ?, ?, ...)`,
   *   your chunk length is just `variableLimit`.
   * - If you're binding 1 param per 1 value per chunk, but using that
   *   param in multiple positions in the query (for example, `WHERE url_hash
   *   IN (hash(?1), hash(?2), ...) AND url IN (?1, ?2, ...)`), you can use the
   *   `?NNN` syntax with a chunk length of `variableLimit`.
   * - If you're binding N params per 1 value per chunk (for example, if you
   *   have a list of items with GUIDs and parent GUIDs, and you want to bind
   *   both), your chunk length is `variableLimit / N`, since you're binding
   *   two params for each element.
   * - If you're binding K params per L values per chunk, plus M fixed ones
   *   (for example, `WHERE parentGuid = :parentGuid AND guid IN (?, ?, ...)`),
   *   your chunk length is `variableLimit - M`, to ensure there's space for the
   *   fixed variables.
   *
   * If you bind more params than this limit, `create{Async}Statement` will
   * fail with a "too many SQL variables" error.
   * It's possible to lower the limit, but it's not possible to set it higher
   * than the default value, passing an higher value will silently truncate to
   * the default. Lowering the limit is particularly useful for testing code
   * that may bind many variables.
   */
  attribute int32_t variableLimit;

  /**
   * Returns true if a transaction is active on this connection.
   *
   * Note that this is true if a transaction is active on the connection,
   * regardless of how it was opened. There are several ways to open one:
   *
   * 1. Explicitly calling `beginTransaction` on a `mozIStorageConnection`.
   * 2. Calling `executeSimpleSQL("BEGIN")` or
   *    `createStatement("BEGIN").execute()` on a `mozIStorageConnection`.
   * 3. Executing an async statement, like
   *    `createAsyncStatement("BEGIN").executeAsync(...)`. This is what
   *    `Sqlite.sys.mjs` does under the hood.
   *
   * Because of this, it's important *not* to use this attribute to decide
   * whether to *commit* the active transaction, because the caller that opened
   * it may not expect that. This is why both `mozStorageTransaction` and
   * `Sqlite.sys.mjs` use an internal variable (`mHasTransaction` for the former;
   * `_hasInProgressTransaction` for the latter) to check if their transaction
   * is already in progress, instead of just checking this attribute before
   * committing. Otherwise, mozStorage might accidentally commit (or roll back!)
   * a transaction started by `Sqlite.sys.mjs`, and vice versa.
   */
  readonly attribute boolean transactionInProgress;

  /**
   * Close this database connection, allowing all pending statements
   * to complete first.
   *
   * @param aCallback [optional]
   *        A callback that will be notified when the close is completed,
   *        with the following arguments:
   *        - status: the status of the call
   *        - value: |null|
   *
   * @throws NS_ERROR_NOT_SAME_THREAD
   *         If called on a thread other than the one that opened it.  The
   *         callback will not be dispatched.
   * @throws NS_ERROR_NOT_INITIALIZED
   *         If called on a connection that has already been closed or was
   *         never properly opened.  The callback will still be dispatched
   *         to the main thread despite the returned error.
   * @note If this call should fail, the callback won't be invoked.
   */
  void asyncClose([optional] in mozIStorageCompletionCallback aCallback);

  /**
   * Forcibly closes a database connection synchronously.
   * This should only be used when it's required to close and replace the
   * database synchronously to return control to the consumer, for example in
   * case of a detected corruption on database opening.
   * Since this spins the events loop, it should be used only in very particular
   * and rare situations, or it may cause unexpected consequences (crashes).
   *
   * @throws NS_ERROR_NOT_SAME_THREAD
   *         If called on a thread other than the one that opened it.
   */
  [noscript] void spinningSynchronousClose();

  /**
   * Clone a database connection and make the clone read only if needed.
   * SQL Functions and attached on-disk databases are applied to the new clone.
   *
   * @param aReadOnly
   *        If true, the returned database should be put into read-only mode.
   *
   * @param aCallback
   *        A callback that will be notified when the operation is complete,
   *        with the following arguments:
   *        - status: the status of the operation
   *        - value: in case of success, an intance of
   *             mozIStorageAsyncConnection cloned from this one.
   *
   * @throws NS_ERROR_NOT_SAME_THREAD
   *         If is called on a thread other than the one that opened it.
   * @throws NS_ERROR_UNEXPECTED
   *         If this connection is a memory database.
   *
   * @note If your connection is already read-only, you will get a read-only
   *       clone.
   * @note The resulting connection will implement `mozIStorageConnection`, but
   *       all synchronous methods will throw if called from the main thread.
   * @note Due to a bug in SQLite, if you use the shared cache
   *       (see mozIStorageService), you end up with the same privileges as the
   *       first connection opened regardless of what is specified in aReadOnly.
   * @note The following pragmas are copied over to a read-only clone:
   *        - cache_size
   *        - temp_store
   *       The following pragmas are copied over to a writeable clone:
   *        - cache_size
   *        - temp_store
   *        - foreign_keys
   *        - journal_size_limit
   *        - synchronous
   *        - wal_autocheckpoint
   *       All SQL functions are copied over to read-only and writeable clones.
   *       Additionally, all temporary tables, triggers, and views, as well as
   *       any indexes on temporary tables, are copied over to writeable clones.
   *       For temporary tables, only the schemas are copied, not their
   *       contents.
   */
  void asyncClone(in boolean aReadOnly,
                  in mozIStorageCompletionCallback aCallback);

  /**
   * The current database nsIFile.  Null if the database
   * connection refers to an in-memory database.
   */
  readonly attribute nsIFile databaseFile;

  /**
   * Causes any pending database operation to abort and return at the first
   * opportunity.
   * @note this cannot be used on mozIStorageConnection unless the connection is
   *       explicitly marked as `interruptible`. For more details, please
   *       refer to CONNECTION_INTERRUPTIBLE in mozIStorageService.
   * @note operations that are nearly complete may still be able to complete.
   * @throws if used on an unsupported connection type, or a closed connection.
   */
  void interrupt();

  /**
   * Vacuum the main database plus all the attached one.
   * If the database is in auto_vacuum = INCREMENTAL mode, this executes an
   * incremental_vacuum, otherwise it will always execute a full vacuum.
   *
   * While it's possible to invoke this method directly, it's suggested, when
   * possible, to use the VacuumManager instead.
   * That means registering your component for the "vacuum-participant" XPCOM
   * category, and implement the mozIStorageVacuumParticipant interface.
   *
   * @param [aCallback] Completion callback invoked once the operation is
   *        complete.
   * @param [aUseIncremental] When set to true, this will try to convert the
   *        main schema to auto_vacuum = INCREMENTAL mode, if it's not set yet.
   *        When set to false, it will try to set auto_vacuum = NONE.
   *        Note a full vacuum will be executed if the auto_vacuum mode must be
   *        changed, otherwise an incremental vacuum will happen if the database
   *        is already in INCREMENTAL mode.
   * @param [aSetPageSize] This can be used to change the database page_size, a
   *        full vacuum will be executed to persist the change. If the page
   *        size is already correct, or you pass 0, this will be a no-op.
   * @throws If it's not possible to start the async vacuum operation, note in
   *         this case the callback won't be invoked.
   * @note Vacuum will fail inside a transaction, or if there is an ongoing
   *       read statement.
   */
  void asyncVacuum(
    [optional] in mozIStorageCompletionCallback aCallback,
    [optional] in boolean aUseIncremental,
    [optional] in long aSetPageSize
  );

  //////////////////////////////////////////////////////////////////////////////
  //// Statement creation

  /**
   * Create an asynchronous statement for the given SQL. An
   * asynchronous statement can only be used to dispatch asynchronous
   * requests to the asynchronous execution thread and cannot be used
   * to take any synchronous actions on the database.
   *
   * The expression may use ? to indicate sequential numbered arguments,
   * ?1, ?2 etc. to indicate specific numbered arguments or :name and
   * $var to indicate named arguments.
   *
   * @param aSQLStatement
   *        The SQL statement to execute.
   * @return a new mozIStorageAsyncStatement
   * @note The statement is created lazily on first execution.
   */
  mozIStorageAsyncStatement createAsyncStatement(in AUTF8String aSQLStatement);

  /**
   * Execute an array of statements created with this connection using
   * any currently bound parameters. When the array contains multiple
   * statements, the execution is wrapped in a single
   * transaction. These statements can be reused immediately, and
   * reset does not need to be called.
   *
   * @param aStatements
   *        The array of statements to execute asynchronously, in the order they
   *        are given in the array.
   * @param aCallback [optional]
   *        The callback object that will be notified of progress, errors, and
   *        completion.
   * @return an object that can be used to cancel the statements execution.
   *
   * @note If you have any custom defined functions, they must be
   *        re-entrant since they can be called on multiple threads.
   */
  mozIStoragePendingStatement executeAsync(
    in Array<mozIStorageBaseStatement> aStatements,
    [optional] in mozIStorageStatementCallback aCallback
  );

  /**
   * Execute asynchronously an SQL expression, expecting no arguments.
   *
   * @param aSQLStatement
   *        The SQL statement to execute
   * @param aCallback [optional]
   *        The callback object that will be notified of progress, errors, and
   *        completion.
   * @return an object that can be used to cancel the statement execution.
   */
  mozIStoragePendingStatement executeSimpleSQLAsync(
    in AUTF8String aSQLStatement,
    [optional] in mozIStorageStatementCallback aCallback);


  /**
   * Loads a Sqlite Run-Time Loadable Extension as defined at
   * https://www.sqlite.org/loadext.html.
   * Only a predetermined list of extensions can be loaded, that are statically
   * linked in the shared library containing SQLite. The currently supported
   * extensions are:
   *   - fts5
   *     A Full-Text search module, see https://www.sqlite.org/fts5.html
   *
   * New extensions can be added to the third_party/sqlite3/ext/ folder and then
   * to this list, after a Storage peer has reviewed the request by verifying
   * licensing, and code reliability.
   * Extensions that must be loaded for all the connections should instead use
   * sqlite3_auto_extension() (this must happen after sqlite3_config(), as it
   * implicitly calls sqlite3_initialize()).
   *
   * @param aExtensionName
   *        The extension to load, see the above list for supported values.
   * @param aCallback
   *        A callback that will be notified when the operation is complete,
   *        with the following arguments:
   *        - status: the status of the operation, use this to check if loading
   *          the extension was successful as it may be partly asynchronous.
   *        - value: unused.
   * @throws NS_ERROR_INVALID_ARG
   *         For unsupported extension names.
   * @throws NS_ERROR_NOT_INITIALIZED
   *         If the connection is not open.
   * @throws NS_ERROR_UEXPECTED
   *         If it was not possible to enable extensions loading.
   */
  void loadExtension(in AUTF8String aExtensionName,
                     [optional] in mozIStorageCompletionCallback aCallback);

  //////////////////////////////////////////////////////////////////////////////
  //// Functions

  /**
   * Create a new SQL function.  If you use your connection on multiple threads,
   * your function needs to be threadsafe, or it should only be called on one
   * thread.
   *
   * @param aFunctionName
   *        The name of function to create, as seen in SQL.
   * @param aNumArguments
   *        The number of arguments the function takes. Pass -1 for
   *        variable-argument functions.
   * @param aFunction
   *        The instance of mozIStorageFunction, which implements the function
   *        in question.
   */
  void createFunction(in AUTF8String aFunctionName,
                      in long aNumArguments,
                      in mozIStorageFunction aFunction);

  /**
   * Delete custom SQL function.
   *
   * @param aFunctionName
   *        The name of function to remove.
   */
  void removeFunction(in AUTF8String aFunctionName);

  /**
   * Sets a progress handler. Only one handler can be registered at a time.
   * If you need more than one, you need to chain them yourself.  This progress
   * handler should be threadsafe if you use this connection object on more than
   * one thread.
   *
   * @param aGranularity
   *        The number of SQL virtual machine steps between progress handler
   *        callbacks.
   * @param aHandler
   *        The instance of mozIStorageProgressHandler.
   * @return previous registered handler.
   */
  mozIStorageProgressHandler setProgressHandler(in int32_t aGranularity,
                                                in mozIStorageProgressHandler aHandler);

  /**
   * Remove a progress handler.
   *
   * @return previous registered handler.
   */
  mozIStorageProgressHandler removeProgressHandler();

  /**
   * Makes a copy of a database asynchronously. This method can do an online
   * backup of the database file, even if there are open connections actively
   * using it (as a normal file copy can only be made if no connections are
   * open on the database).
   *
   * While the copy is in the process of being made, the destination file
   * will have a .tmp extension appended to it. In the event of a crash
   * during the copy, this .tmp file will continue to exist, but will be
   * an unusable partial copy.
   *
   * Once the copy has been completed, this method will automatically remove
   * the .tmp extension.
   *
   * @param aDestinationFile
   *        The destination on the file system to write the database copy.
   * @param aCallback
   *        A callback that will be notified when the operation is complete,
   *        with the following arguments:
   *        - status: the status of the operation, use this to check if making
   *                  the copy was successful.
   *        - value: unused.
   * @param [aPagesPerStep=5]
   *        The number of pages in the database to copy per step. Defaults to 5
   *        if omitted or set to 0.
   * @param [aStepDelayMs=250]
   *        The number of milliseconds to wait between each step. Defaults to
   *        250 if omitted or set to 0.
   * @throws NS_ERROR_ABORT
   *         If the application has begun the process of shutting down already.
   * @throws NS_ERROR_NOT_INITIALIZED
   *         If the connection has already started or completed closing.
   * @throws NS_ERROR_NOT_AVAILABLE
   *         If the database does not support asynchronous operations.
   * @throws NS_ERROR_NOT_INITIALIZED
   *         If the execution thread cannot be acquired.
   */
  void backupToFileAsync(in nsIFile aDestinationFile,
                         in mozIStorageCompletionCallback aCallback,
                         [optional] in unsigned long aPagesPerStep,
                         [optional] in unsigned long aStepDelayMs);
};