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1 : : /* GIO - GLib Input, Output and Streaming Library
2 : : *
3 : : * Copyright (C) 2009 Red Hat, Inc.
4 : : *
5 : : * SPDX-License-Identifier: LGPL-2.1-or-later
6 : : *
7 : : * This library is free software; you can redistribute it and/or
8 : : * modify it under the terms of the GNU Lesser General Public
9 : : * License as published by the Free Software Foundation; either
10 : : * version 2.1 of the License, or (at your option) any later version.
11 : : *
12 : : * This library is distributed in the hope that it will be useful,
13 : : * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 : : * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 : : * Lesser General Public License for more details.
16 : : *
17 : : * You should have received a copy of the GNU Lesser General
18 : : * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
19 : : *
20 : : * Author: Alexander Larsson <alexl@redhat.com>
21 : : */
22 : :
23 : : #include "config.h"
24 : : #include "gasyncinitable.h"
25 : : #include "gasyncresult.h"
26 : : #include "gsimpleasyncresult.h"
27 : : #include "gtask.h"
28 : : #include "glibintl.h"
29 : :
30 : :
31 : : /**
32 : : * GAsyncInitable:
33 : : *
34 : : * `GAsyncInitable` is an interface for asynchronously initializable objects.
35 : : *
36 : : * This is the asynchronous version of [iface@Gio.Initable]; it behaves the same
37 : : * in all ways except that initialization is asynchronous. For more details
38 : : * see the descriptions on `GInitable`.
39 : : *
40 : : * A class may implement both the `GInitable` and `GAsyncInitable` interfaces.
41 : : *
42 : : * Users of objects implementing this are not intended to use the interface
43 : : * method directly; instead it will be used automatically in various ways.
44 : : * For C applications you generally just call [func@Gio.AsyncInitable.new_async]
45 : : * directly, or indirectly via a foo_thing_new_async() wrapper. This will call
46 : : * [method@Gio.AsyncInitable.init_async] under the covers, calling back with `NULL`
47 : : * and a set `GError` on failure.
48 : : *
49 : : * A typical implementation might look something like this:
50 : : *
51 : : * ```c
52 : : * enum {
53 : : * NOT_INITIALIZED,
54 : : * INITIALIZING,
55 : : * INITIALIZED
56 : : * };
57 : : *
58 : : * static void
59 : : * _foo_ready_cb (Foo *self)
60 : : * {
61 : : * GList *l;
62 : : *
63 : : * self->priv->state = INITIALIZED;
64 : : *
65 : : * for (l = self->priv->init_results; l != NULL; l = l->next)
66 : : * {
67 : : * GTask *task = l->data;
68 : : *
69 : : * if (self->priv->success)
70 : : * g_task_return_boolean (task, TRUE);
71 : : * else
72 : : * g_task_return_new_error (task, ...);
73 : : * g_object_unref (task);
74 : : * }
75 : : *
76 : : * g_list_free (self->priv->init_results);
77 : : * self->priv->init_results = NULL;
78 : : * }
79 : : *
80 : : * static void
81 : : * foo_init_async (GAsyncInitable *initable,
82 : : * int io_priority,
83 : : * GCancellable *cancellable,
84 : : * GAsyncReadyCallback callback,
85 : : * gpointer user_data)
86 : : * {
87 : : * Foo *self = FOO (initable);
88 : : * GTask *task;
89 : : *
90 : : * task = g_task_new (initable, cancellable, callback, user_data);
91 : : * g_task_set_name (task, G_STRFUNC);
92 : : *
93 : : * switch (self->priv->state)
94 : : * {
95 : : * case NOT_INITIALIZED:
96 : : * _foo_get_ready (self);
97 : : * self->priv->init_results = g_list_append (self->priv->init_results,
98 : : * task);
99 : : * self->priv->state = INITIALIZING;
100 : : * break;
101 : : * case INITIALIZING:
102 : : * self->priv->init_results = g_list_append (self->priv->init_results,
103 : : * task);
104 : : * break;
105 : : * case INITIALIZED:
106 : : * if (!self->priv->success)
107 : : * g_task_return_new_error (task, ...);
108 : : * else
109 : : * g_task_return_boolean (task, TRUE);
110 : : * g_object_unref (task);
111 : : * break;
112 : : * }
113 : : * }
114 : : *
115 : : * static gboolean
116 : : * foo_init_finish (GAsyncInitable *initable,
117 : : * GAsyncResult *result,
118 : : * GError **error)
119 : : * {
120 : : * g_return_val_if_fail (g_task_is_valid (result, initable), FALSE);
121 : : *
122 : : * return g_task_propagate_boolean (G_TASK (result), error);
123 : : * }
124 : : *
125 : : * static void
126 : : * foo_async_initable_iface_init (gpointer g_iface,
127 : : * gpointer data)
128 : : * {
129 : : * GAsyncInitableIface *iface = g_iface;
130 : : *
131 : : * iface->init_async = foo_init_async;
132 : : * iface->init_finish = foo_init_finish;
133 : : * }
134 : : * ```
135 : : *
136 : : * Since: 2.22
137 : : */
138 : :
139 : : static void g_async_initable_real_init_async (GAsyncInitable *initable,
140 : : int io_priority,
141 : : GCancellable *cancellable,
142 : : GAsyncReadyCallback callback,
143 : : gpointer user_data);
144 : : static gboolean g_async_initable_real_init_finish (GAsyncInitable *initable,
145 : : GAsyncResult *res,
146 : : GError **error);
147 : :
148 : :
149 : : typedef GAsyncInitableIface GAsyncInitableInterface;
150 : 4918 : G_DEFINE_INTERFACE (GAsyncInitable, g_async_initable, G_TYPE_OBJECT)
151 : :
152 : :
153 : : static void
154 : 124 : g_async_initable_default_init (GAsyncInitableInterface *iface)
155 : : {
156 : 124 : iface->init_async = g_async_initable_real_init_async;
157 : 124 : iface->init_finish = g_async_initable_real_init_finish;
158 : 124 : }
159 : :
160 : : /**
161 : : * g_async_initable_init_async:
162 : : * @initable: a #GAsyncInitable.
163 : : * @io_priority: the [I/O priority](iface.AsyncResult.html#io-priority) of the operation
164 : : * @cancellable: optional #GCancellable object, %NULL to ignore.
165 : : * @callback: a #GAsyncReadyCallback to call when the request is satisfied
166 : : * @user_data: the data to pass to callback function
167 : : *
168 : : * Starts asynchronous initialization of the object implementing the
169 : : * interface. This must be done before any real use of the object after
170 : : * initial construction. If the object also implements #GInitable you can
171 : : * optionally call g_initable_init() instead.
172 : : *
173 : : * This method is intended for language bindings. If writing in C,
174 : : * g_async_initable_new_async() should typically be used instead.
175 : : *
176 : : * When the initialization is finished, @callback will be called. You can
177 : : * then call g_async_initable_init_finish() to get the result of the
178 : : * initialization.
179 : : *
180 : : * Implementations may also support cancellation. If @cancellable is not
181 : : * %NULL, then initialization can be cancelled by triggering the cancellable
182 : : * object from another thread. If the operation was cancelled, the error
183 : : * %G_IO_ERROR_CANCELLED will be returned. If @cancellable is not %NULL, and
184 : : * the object doesn't support cancellable initialization, the error
185 : : * %G_IO_ERROR_NOT_SUPPORTED will be returned.
186 : : *
187 : : * As with #GInitable, if the object is not initialized, or initialization
188 : : * returns with an error, then all operations on the object except
189 : : * g_object_ref() and g_object_unref() are considered to be invalid, and
190 : : * have undefined behaviour. They will often fail with g_critical() or
191 : : * g_warning(), but this must not be relied on.
192 : : *
193 : : * Callers should not assume that a class which implements #GAsyncInitable can
194 : : * be initialized multiple times; for more information, see g_initable_init().
195 : : * If a class explicitly supports being initialized multiple times,
196 : : * implementation requires yielding all subsequent calls to init_async() on the
197 : : * results of the first call.
198 : : *
199 : : * For classes that also support the #GInitable interface, the default
200 : : * implementation of this method will run the g_initable_init() function
201 : : * in a thread, so if you want to support asynchronous initialization via
202 : : * threads, just implement the #GAsyncInitable interface without overriding
203 : : * any interface methods.
204 : : *
205 : : * Since: 2.22
206 : : */
207 : : void
208 : 467 : g_async_initable_init_async (GAsyncInitable *initable,
209 : : int io_priority,
210 : : GCancellable *cancellable,
211 : : GAsyncReadyCallback callback,
212 : : gpointer user_data)
213 : : {
214 : : GAsyncInitableIface *iface;
215 : :
216 : 467 : g_return_if_fail (G_IS_ASYNC_INITABLE (initable));
217 : :
218 : 467 : iface = G_ASYNC_INITABLE_GET_IFACE (initable);
219 : :
220 : 467 : (* iface->init_async) (initable, io_priority, cancellable, callback, user_data);
221 : : }
222 : :
223 : : /**
224 : : * g_async_initable_init_finish:
225 : : * @initable: a #GAsyncInitable.
226 : : * @res: a #GAsyncResult.
227 : : * @error: a #GError location to store the error occurring, or %NULL to
228 : : * ignore.
229 : : *
230 : : * Finishes asynchronous initialization and returns the result.
231 : : * See g_async_initable_init_async().
232 : : *
233 : : * Returns: %TRUE if successful. If an error has occurred, this function
234 : : * will return %FALSE and set @error appropriately if present.
235 : : *
236 : : * Since: 2.22
237 : : */
238 : : gboolean
239 : 465 : g_async_initable_init_finish (GAsyncInitable *initable,
240 : : GAsyncResult *res,
241 : : GError **error)
242 : : {
243 : : GAsyncInitableIface *iface;
244 : :
245 : 465 : g_return_val_if_fail (G_IS_ASYNC_INITABLE (initable), FALSE);
246 : 465 : g_return_val_if_fail (G_IS_ASYNC_RESULT (res), FALSE);
247 : :
248 : 465 : if (g_async_result_legacy_propagate_error (res, error))
249 : 0 : return FALSE;
250 : :
251 : 465 : iface = G_ASYNC_INITABLE_GET_IFACE (initable);
252 : :
253 : 465 : return (* iface->init_finish) (initable, res, error);
254 : : }
255 : :
256 : : static void
257 : 463 : async_init_thread (GTask *task,
258 : : gpointer source_object,
259 : : gpointer task_data,
260 : : GCancellable *cancellable)
261 : : {
262 : 463 : GError *error = NULL;
263 : :
264 : 463 : if (g_initable_init (G_INITABLE (source_object), cancellable, &error))
265 : 460 : g_task_return_boolean (task, TRUE);
266 : : else
267 : 3 : g_task_return_error (task, error);
268 : 463 : }
269 : :
270 : : static void
271 : 463 : g_async_initable_real_init_async (GAsyncInitable *initable,
272 : : int io_priority,
273 : : GCancellable *cancellable,
274 : : GAsyncReadyCallback callback,
275 : : gpointer user_data)
276 : : {
277 : : GTask *task;
278 : :
279 : 463 : g_return_if_fail (G_IS_INITABLE (initable));
280 : :
281 : 463 : task = g_task_new (initable, cancellable, callback, user_data);
282 : 463 : g_task_set_source_tag (task, g_async_initable_real_init_async);
283 : 463 : g_task_set_priority (task, io_priority);
284 : 463 : g_task_run_in_thread (task, async_init_thread);
285 : 463 : g_object_unref (task);
286 : : }
287 : :
288 : : static gboolean
289 : 461 : g_async_initable_real_init_finish (GAsyncInitable *initable,
290 : : GAsyncResult *res,
291 : : GError **error)
292 : : {
293 : : /* For backward compatibility we have to process GSimpleAsyncResults
294 : : * even though g_async_initable_real_init_async doesn't generate
295 : : * them any more.
296 : : */
297 : : G_GNUC_BEGIN_IGNORE_DEPRECATIONS
298 : 461 : if (G_IS_SIMPLE_ASYNC_RESULT (res))
299 : : {
300 : 0 : GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (res);
301 : 0 : if (g_simple_async_result_propagate_error (simple, error))
302 : 0 : return FALSE;
303 : : else
304 : 0 : return TRUE;
305 : : }
306 : : G_GNUC_END_IGNORE_DEPRECATIONS
307 : :
308 : 461 : g_return_val_if_fail (g_task_is_valid (res, initable), FALSE);
309 : :
310 : 461 : return g_task_propagate_boolean (G_TASK (res), error);
311 : : }
312 : :
313 : : /**
314 : : * g_async_initable_new_async:
315 : : * @object_type: a #GType supporting #GAsyncInitable.
316 : : * @io_priority: the [I/O priority](iface.AsyncResult.html#io-priority) of the operation
317 : : * @cancellable: optional #GCancellable object, %NULL to ignore.
318 : : * @callback: a #GAsyncReadyCallback to call when the initialization is
319 : : * finished
320 : : * @user_data: the data to pass to callback function
321 : : * @first_property_name: (nullable): the name of the first property, or %NULL if no
322 : : * properties
323 : : * @...: the value of the first property, followed by other property
324 : : * value pairs, and ended by %NULL.
325 : : *
326 : : * Helper function for constructing #GAsyncInitable object. This is
327 : : * similar to g_object_new() but also initializes the object asynchronously.
328 : : *
329 : : * When the initialization is finished, @callback will be called. You can
330 : : * then call g_async_initable_new_finish() to get the new object and check
331 : : * for any errors.
332 : : *
333 : : * Since: 2.22
334 : : */
335 : : void
336 : 426 : g_async_initable_new_async (GType object_type,
337 : : int io_priority,
338 : : GCancellable *cancellable,
339 : : GAsyncReadyCallback callback,
340 : : gpointer user_data,
341 : : const gchar *first_property_name,
342 : : ...)
343 : : {
344 : : va_list var_args;
345 : :
346 : 426 : va_start (var_args, first_property_name);
347 : 426 : g_async_initable_new_valist_async (object_type,
348 : : first_property_name, var_args,
349 : : io_priority, cancellable,
350 : : callback, user_data);
351 : 426 : va_end (var_args);
352 : 426 : }
353 : :
354 : : /**
355 : : * g_async_initable_newv_async:
356 : : * @object_type: a #GType supporting #GAsyncInitable.
357 : : * @n_parameters: the number of parameters in @parameters
358 : : * @parameters: the parameters to use to construct the object
359 : : * @io_priority: the [I/O priority](iface.AsyncResult.html#io-priority) of the operation
360 : : * @cancellable: optional #GCancellable object, %NULL to ignore.
361 : : * @callback: a #GAsyncReadyCallback to call when the initialization is
362 : : * finished
363 : : * @user_data: the data to pass to callback function
364 : : *
365 : : * Helper function for constructing #GAsyncInitable object. This is
366 : : * similar to g_object_newv() but also initializes the object asynchronously.
367 : : *
368 : : * When the initialization is finished, @callback will be called. You can
369 : : * then call g_async_initable_new_finish() to get the new object and check
370 : : * for any errors.
371 : : *
372 : : * Since: 2.22
373 : : * Deprecated: 2.54: Use g_object_new_with_properties() and
374 : : * g_async_initable_init_async() instead. See #GParameter for more information.
375 : : */
376 : : G_GNUC_BEGIN_IGNORE_DEPRECATIONS
377 : : void
378 : 0 : g_async_initable_newv_async (GType object_type,
379 : : guint n_parameters,
380 : : GParameter *parameters,
381 : : int io_priority,
382 : : GCancellable *cancellable,
383 : : GAsyncReadyCallback callback,
384 : : gpointer user_data)
385 : : {
386 : : GObject *obj;
387 : :
388 : 0 : g_return_if_fail (G_TYPE_IS_ASYNC_INITABLE (object_type));
389 : :
390 : 0 : obj = g_object_newv (object_type, n_parameters, parameters);
391 : :
392 : 0 : g_async_initable_init_async (G_ASYNC_INITABLE (obj),
393 : : io_priority, cancellable,
394 : : callback, user_data);
395 : 0 : g_object_unref (obj); /* Passed ownership to async call */
396 : : }
397 : : G_GNUC_END_IGNORE_DEPRECATIONS
398 : :
399 : : /**
400 : : * g_async_initable_new_valist_async:
401 : : * @object_type: a #GType supporting #GAsyncInitable.
402 : : * @first_property_name: the name of the first property, followed by
403 : : * the value, and other property value pairs, and ended by %NULL.
404 : : * @var_args: The var args list generated from @first_property_name.
405 : : * @io_priority: the [I/O priority](iface.AsyncResult.html#io-priority) of the operation
406 : : * @cancellable: optional #GCancellable object, %NULL to ignore.
407 : : * @callback: a #GAsyncReadyCallback to call when the initialization is
408 : : * finished
409 : : * @user_data: the data to pass to callback function
410 : : *
411 : : * Helper function for constructing #GAsyncInitable object. This is
412 : : * similar to g_object_new_valist() but also initializes the object
413 : : * asynchronously.
414 : : *
415 : : * When the initialization is finished, @callback will be called. You can
416 : : * then call g_async_initable_new_finish() to get the new object and check
417 : : * for any errors.
418 : : *
419 : : * Since: 2.22
420 : : */
421 : : void
422 : 426 : g_async_initable_new_valist_async (GType object_type,
423 : : const gchar *first_property_name,
424 : : va_list var_args,
425 : : int io_priority,
426 : : GCancellable *cancellable,
427 : : GAsyncReadyCallback callback,
428 : : gpointer user_data)
429 : : {
430 : : GObject *obj;
431 : :
432 : 426 : g_return_if_fail (G_TYPE_IS_ASYNC_INITABLE (object_type));
433 : :
434 : 426 : obj = g_object_new_valist (object_type,
435 : : first_property_name,
436 : : var_args);
437 : :
438 : 426 : g_async_initable_init_async (G_ASYNC_INITABLE (obj),
439 : : io_priority, cancellable,
440 : : callback, user_data);
441 : 426 : g_object_unref (obj); /* Passed ownership to async call */
442 : : }
443 : :
444 : : /**
445 : : * g_async_initable_new_finish:
446 : : * @initable: the #GAsyncInitable from the callback
447 : : * @res: the #GAsyncResult from the callback
448 : : * @error: return location for errors, or %NULL to ignore
449 : : *
450 : : * Finishes the async construction for the various g_async_initable_new
451 : : * calls, returning the created object or %NULL on error.
452 : : *
453 : : * Returns: (type GObject.Object) (transfer full): a newly created #GObject,
454 : : * or %NULL on error. Free with g_object_unref().
455 : : *
456 : : * Since: 2.22
457 : : */
458 : : GObject *
459 : 426 : g_async_initable_new_finish (GAsyncInitable *initable,
460 : : GAsyncResult *res,
461 : : GError **error)
462 : : {
463 : 426 : if (g_async_initable_init_finish (initable, res, error))
464 : 426 : return g_object_ref (G_OBJECT (initable));
465 : : else
466 : 0 : return NULL;
467 : : }
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