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1 office 1 /* GIO - GLib Input, Output and Streaming Library
2 *
3 * Copyright © 2008 codethink
4 * Copyright © 2009 Red Hat, Inc.
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General
17 * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
18 *
19 * Authors: Ryan Lortie <desrt@desrt.ca>
20 * Alexander Larsson <alexl@redhat.com>
21 */
22  
23 #include "config.h"
24 #include <glib.h>
25 #include "glibintl.h"
26  
27 #include "giostream.h"
28 #include "gasyncresult.h"
29 #include "gioprivate.h"
30 #include "gtask.h"
31  
32 /**
33 * SECTION:giostream
34 * @short_description: Base class for implementing read/write streams
35 * @include: gio/gio.h
36 * @see_also: #GInputStream, #GOutputStream
37 *
38 * GIOStream represents an object that has both read and write streams.
39 * Generally the two streams act as separate input and output streams,
40 * but they share some common resources and state. For instance, for
41 * seekable streams, both streams may use the same position.
42 *
43 * Examples of #GIOStream objects are #GSocketConnection, which represents
44 * a two-way network connection; and #GFileIOStream, which represents a
45 * file handle opened in read-write mode.
46 *
47 * To do the actual reading and writing you need to get the substreams
48 * with g_io_stream_get_input_stream() and g_io_stream_get_output_stream().
49 *
50 * The #GIOStream object owns the input and the output streams, not the other
51 * way around, so keeping the substreams alive will not keep the #GIOStream
52 * object alive. If the #GIOStream object is freed it will be closed, thus
53 * closing the substreams, so even if the substreams stay alive they will
54 * always return %G_IO_ERROR_CLOSED for all operations.
55 *
56 * To close a stream use g_io_stream_close() which will close the common
57 * stream object and also the individual substreams. You can also close
58 * the substreams themselves. In most cases this only marks the
59 * substream as closed, so further I/O on it fails but common state in the
60 * #GIOStream may still be open. However, some streams may support
61 * "half-closed" states where one direction of the stream is actually shut down.
62 *
63 * Operations on #GIOStreams cannot be started while another operation on the
64 * #GIOStream or its substreams is in progress. Specifically, an application can
65 * read from the #GInputStream and write to the #GOutputStream simultaneously
66 * (either in separate threads, or as asynchronous operations in the same
67 * thread), but an application cannot start any #GIOStream operation while there
68 * is a #GIOStream, #GInputStream or #GOutputStream operation in progress, and
69 * an application can’t start any #GInputStream or #GOutputStream operation
70 * while there is a #GIOStream operation in progress.
71 *
72 * This is a product of individual stream operations being associated with a
73 * given #GMainContext (the thread-default context at the time the operation was
74 * started), rather than entire streams being associated with a single
75 * #GMainContext.
76 *
77 * GIO may run operations on #GIOStreams from other (worker) threads, and this
78 * may be exposed to application code in the behaviour of wrapper streams, such
79 * as #GBufferedInputStream or #GTlsConnection. With such wrapper APIs,
80 * application code may only run operations on the base (wrapped) stream when
81 * the wrapper stream is idle. Note that the semantics of such operations may
82 * not be well-defined due to the state the wrapper stream leaves the base
83 * stream in (though they are guaranteed not to crash).
84 *
85 * Since: 2.22
86 */
87  
88 enum
89 {
90 PROP_0,
91 PROP_INPUT_STREAM,
92 PROP_OUTPUT_STREAM,
93 PROP_CLOSED
94 };
95  
96 struct _GIOStreamPrivate {
97 guint closed : 1;
98 guint pending : 1;
99 };
100  
101 static gboolean g_io_stream_real_close (GIOStream *stream,
102 GCancellable *cancellable,
103 GError **error);
104 static void g_io_stream_real_close_async (GIOStream *stream,
105 int io_priority,
106 GCancellable *cancellable,
107 GAsyncReadyCallback callback,
108 gpointer user_data);
109 static gboolean g_io_stream_real_close_finish (GIOStream *stream,
110 GAsyncResult *result,
111 GError **error);
112  
113 G_DEFINE_ABSTRACT_TYPE_WITH_PRIVATE (GIOStream, g_io_stream, G_TYPE_OBJECT)
114  
115 static void
116 g_io_stream_dispose (GObject *object)
117 {
118 GIOStream *stream;
119  
120 stream = G_IO_STREAM (object);
121  
122 if (!stream->priv->closed)
123 g_io_stream_close (stream, NULL, NULL);
124  
125 G_OBJECT_CLASS (g_io_stream_parent_class)->dispose (object);
126 }
127  
128 static void
129 g_io_stream_init (GIOStream *stream)
130 {
131 stream->priv = g_io_stream_get_instance_private (stream);
132 }
133  
134 static void
135 g_io_stream_get_property (GObject *object,
136 guint prop_id,
137 GValue *value,
138 GParamSpec *pspec)
139 {
140 GIOStream *stream = G_IO_STREAM (object);
141  
142 switch (prop_id)
143 {
144 case PROP_CLOSED:
145 g_value_set_boolean (value, stream->priv->closed);
146 break;
147  
148 case PROP_INPUT_STREAM:
149 g_value_set_object (value, g_io_stream_get_input_stream (stream));
150 break;
151  
152 case PROP_OUTPUT_STREAM:
153 g_value_set_object (value, g_io_stream_get_output_stream (stream));
154 break;
155  
156 default:
157 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
158 }
159 }
160  
161 static void
162 g_io_stream_class_init (GIOStreamClass *klass)
163 {
164 GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
165  
166 gobject_class->dispose = g_io_stream_dispose;
167 gobject_class->get_property = g_io_stream_get_property;
168  
169 klass->close_fn = g_io_stream_real_close;
170 klass->close_async = g_io_stream_real_close_async;
171 klass->close_finish = g_io_stream_real_close_finish;
172  
173 g_object_class_install_property (gobject_class, PROP_CLOSED,
174 g_param_spec_boolean ("closed",
175 P_("Closed"),
176 P_("Is the stream closed"),
177 FALSE,
178 G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
179  
180 g_object_class_install_property (gobject_class, PROP_INPUT_STREAM,
181 g_param_spec_object ("input-stream",
182 P_("Input stream"),
183 P_("The GInputStream to read from"),
184 G_TYPE_INPUT_STREAM,
185 G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
186 g_object_class_install_property (gobject_class, PROP_OUTPUT_STREAM,
187 g_param_spec_object ("output-stream",
188 P_("Output stream"),
189 P_("The GOutputStream to write to"),
190 G_TYPE_OUTPUT_STREAM,
191 G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
192 }
193  
194 /**
195 * g_io_stream_is_closed:
196 * @stream: a #GIOStream
197 *
198 * Checks if a stream is closed.
199 *
200 * Returns: %TRUE if the stream is closed.
201 *
202 * Since: 2.22
203 */
204 gboolean
205 g_io_stream_is_closed (GIOStream *stream)
206 {
207 g_return_val_if_fail (G_IS_IO_STREAM (stream), TRUE);
208  
209 return stream->priv->closed;
210 }
211  
212 /**
213 * g_io_stream_get_input_stream:
214 * @stream: a #GIOStream
215 *
216 * Gets the input stream for this object. This is used
217 * for reading.
218 *
219 * Returns: (transfer none): a #GInputStream, owned by the #GIOStream.
220 * Do not free.
221 *
222 * Since: 2.22
223 */
224 GInputStream *
225 g_io_stream_get_input_stream (GIOStream *stream)
226 {
227 GIOStreamClass *klass;
228  
229 klass = G_IO_STREAM_GET_CLASS (stream);
230  
231 g_assert (klass->get_input_stream != NULL);
232  
233 return klass->get_input_stream (stream);
234 }
235  
236 /**
237 * g_io_stream_get_output_stream:
238 * @stream: a #GIOStream
239 *
240 * Gets the output stream for this object. This is used for
241 * writing.
242 *
243 * Returns: (transfer none): a #GOutputStream, owned by the #GIOStream.
244 * Do not free.
245 *
246 * Since: 2.22
247 */
248 GOutputStream *
249 g_io_stream_get_output_stream (GIOStream *stream)
250 {
251 GIOStreamClass *klass;
252  
253 klass = G_IO_STREAM_GET_CLASS (stream);
254  
255 g_assert (klass->get_output_stream != NULL);
256 return klass->get_output_stream (stream);
257 }
258  
259 /**
260 * g_io_stream_has_pending:
261 * @stream: a #GIOStream
262 *
263 * Checks if a stream has pending actions.
264 *
265 * Returns: %TRUE if @stream has pending actions.
266 *
267 * Since: 2.22
268 **/
269 gboolean
270 g_io_stream_has_pending (GIOStream *stream)
271 {
272 g_return_val_if_fail (G_IS_IO_STREAM (stream), FALSE);
273  
274 return stream->priv->pending;
275 }
276  
277 /**
278 * g_io_stream_set_pending:
279 * @stream: a #GIOStream
280 * @error: a #GError location to store the error occurring, or %NULL to
281 * ignore
282 *
283 * Sets @stream to have actions pending. If the pending flag is
284 * already set or @stream is closed, it will return %FALSE and set
285 * @error.
286 *
287 * Returns: %TRUE if pending was previously unset and is now set.
288 *
289 * Since: 2.22
290 */
291 gboolean
292 g_io_stream_set_pending (GIOStream *stream,
293 GError **error)
294 {
295 g_return_val_if_fail (G_IS_IO_STREAM (stream), FALSE);
296  
297 if (stream->priv->closed)
298 {
299 g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
300 _("Stream is already closed"));
301 return FALSE;
302 }
303  
304 if (stream->priv->pending)
305 {
306 g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PENDING,
307 /* Translators: This is an error you get if there is
308 * already an operation running against this stream when
309 * you try to start one */
310 _("Stream has outstanding operation"));
311 return FALSE;
312 }
313  
314 stream->priv->pending = TRUE;
315 return TRUE;
316 }
317  
318 /**
319 * g_io_stream_clear_pending:
320 * @stream: a #GIOStream
321 *
322 * Clears the pending flag on @stream.
323 *
324 * Since: 2.22
325 */
326 void
327 g_io_stream_clear_pending (GIOStream *stream)
328 {
329 g_return_if_fail (G_IS_IO_STREAM (stream));
330  
331 stream->priv->pending = FALSE;
332 }
333  
334 static gboolean
335 g_io_stream_real_close (GIOStream *stream,
336 GCancellable *cancellable,
337 GError **error)
338 {
339 gboolean res;
340  
341 res = g_output_stream_close (g_io_stream_get_output_stream (stream),
342 cancellable, error);
343  
344 /* If this errored out, unset error so that we don't report
345 further errors, but still do the following ops */
346 if (error != NULL && *error != NULL)
347 error = NULL;
348  
349 res &= g_input_stream_close (g_io_stream_get_input_stream (stream),
350 cancellable, error);
351  
352 return res;
353 }
354  
355 /**
356 * g_io_stream_close:
357 * @stream: a #GIOStream
358 * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore
359 * @error: location to store the error occurring, or %NULL to ignore
360 *
361 * Closes the stream, releasing resources related to it. This will also
362 * close the individual input and output streams, if they are not already
363 * closed.
364 *
365 * Once the stream is closed, all other operations will return
366 * %G_IO_ERROR_CLOSED. Closing a stream multiple times will not
367 * return an error.
368 *
369 * Closing a stream will automatically flush any outstanding buffers
370 * in the stream.
371 *
372 * Streams will be automatically closed when the last reference
373 * is dropped, but you might want to call this function to make sure
374 * resources are released as early as possible.
375 *
376 * Some streams might keep the backing store of the stream (e.g. a file
377 * descriptor) open after the stream is closed. See the documentation for
378 * the individual stream for details.
379 *
380 * On failure the first error that happened will be reported, but the
381 * close operation will finish as much as possible. A stream that failed
382 * to close will still return %G_IO_ERROR_CLOSED for all operations.
383 * Still, it is important to check and report the error to the user,
384 * otherwise there might be a loss of data as all data might not be written.
385 *
386 * If @cancellable is not NULL, then the operation can be cancelled by
387 * triggering the cancellable object from another thread. If the operation
388 * was cancelled, the error %G_IO_ERROR_CANCELLED will be returned.
389 * Cancelling a close will still leave the stream closed, but some streams
390 * can use a faster close that doesn't block to e.g. check errors.
391 *
392 * The default implementation of this method just calls close on the
393 * individual input/output streams.
394 *
395 * Returns: %TRUE on success, %FALSE on failure
396 *
397 * Since: 2.22
398 */
399 gboolean
400 g_io_stream_close (GIOStream *stream,
401 GCancellable *cancellable,
402 GError **error)
403 {
404 GIOStreamClass *class;
405 gboolean res;
406  
407 g_return_val_if_fail (G_IS_IO_STREAM (stream), FALSE);
408  
409 class = G_IO_STREAM_GET_CLASS (stream);
410  
411 if (stream->priv->closed)
412 return TRUE;
413  
414 if (!g_io_stream_set_pending (stream, error))
415 return FALSE;
416  
417 if (cancellable)
418 g_cancellable_push_current (cancellable);
419  
420 res = TRUE;
421 if (class->close_fn)
422 res = class->close_fn (stream, cancellable, error);
423  
424 if (cancellable)
425 g_cancellable_pop_current (cancellable);
426  
427 stream->priv->closed = TRUE;
428 g_io_stream_clear_pending (stream);
429  
430 return res;
431 }
432  
433 static void
434 async_ready_close_callback_wrapper (GObject *source_object,
435 GAsyncResult *res,
436 gpointer user_data)
437 {
438 GIOStream *stream = G_IO_STREAM (source_object);
439 GIOStreamClass *klass = G_IO_STREAM_GET_CLASS (stream);
440 GTask *task = user_data;
441 GError *error = NULL;
442 gboolean success;
443  
444 stream->priv->closed = TRUE;
445 g_io_stream_clear_pending (stream);
446  
447 if (g_async_result_legacy_propagate_error (res, &error))
448 success = FALSE;
449 else
450 success = klass->close_finish (stream, res, &error);
451  
452 if (error)
453 g_task_return_error (task, error);
454 else
455 g_task_return_boolean (task, success);
456  
457 g_object_unref (task);
458 }
459  
460 /**
461 * g_io_stream_close_async:
462 * @stream: a #GIOStream
463 * @io_priority: the io priority of the request
464 * @cancellable: (allow-none): optional cancellable object
465 * @callback: (scope async): callback to call when the request is satisfied
466 * @user_data: (closure): the data to pass to callback function
467 *
468 * Requests an asynchronous close of the stream, releasing resources
469 * related to it. When the operation is finished @callback will be
470 * called. You can then call g_io_stream_close_finish() to get
471 * the result of the operation.
472 *
473 * For behaviour details see g_io_stream_close().
474 *
475 * The asynchronous methods have a default fallback that uses threads
476 * to implement asynchronicity, so they are optional for inheriting
477 * classes. However, if you override one you must override all.
478 *
479 * Since: 2.22
480 */
481 void
482 g_io_stream_close_async (GIOStream *stream,
483 int io_priority,
484 GCancellable *cancellable,
485 GAsyncReadyCallback callback,
486 gpointer user_data)
487 {
488 GIOStreamClass *class;
489 GError *error = NULL;
490 GTask *task;
491  
492 g_return_if_fail (G_IS_IO_STREAM (stream));
493  
494 task = g_task_new (stream, cancellable, callback, user_data);
495  
496 if (stream->priv->closed)
497 {
498 g_task_return_boolean (task, TRUE);
499 g_object_unref (task);
500 return;
501 }
502  
503 if (!g_io_stream_set_pending (stream, &error))
504 {
505 g_task_return_error (task, error);
506 g_object_unref (task);
507 return;
508 }
509  
510 class = G_IO_STREAM_GET_CLASS (stream);
511  
512 class->close_async (stream, io_priority, cancellable,
513 async_ready_close_callback_wrapper, task);
514 }
515  
516 /**
517 * g_io_stream_close_finish:
518 * @stream: a #GIOStream
519 * @result: a #GAsyncResult
520 * @error: a #GError location to store the error occurring, or %NULL to
521 * ignore
522 *
523 * Closes a stream.
524 *
525 * Returns: %TRUE if stream was successfully closed, %FALSE otherwise.
526 *
527 * Since: 2.22
528 */
529 gboolean
530 g_io_stream_close_finish (GIOStream *stream,
531 GAsyncResult *result,
532 GError **error)
533 {
534 g_return_val_if_fail (G_IS_IO_STREAM (stream), FALSE);
535 g_return_val_if_fail (g_task_is_valid (result, stream), FALSE);
536  
537 return g_task_propagate_boolean (G_TASK (result), error);
538 }
539  
540  
541 static void
542 close_async_thread (GTask *task,
543 gpointer source_object,
544 gpointer task_data,
545 GCancellable *cancellable)
546 {
547 GIOStream *stream = source_object;
548 GIOStreamClass *class;
549 GError *error = NULL;
550 gboolean result;
551  
552 class = G_IO_STREAM_GET_CLASS (stream);
553 if (class->close_fn)
554 {
555 result = class->close_fn (stream,
556 g_task_get_cancellable (task),
557 &error);
558 if (!result)
559 {
560 g_task_return_error (task, error);
561 return;
562 }
563 }
564  
565 g_task_return_boolean (task, TRUE);
566 }
567  
568 typedef struct
569 {
570 GError *error;
571 gint pending;
572 } CloseAsyncData;
573  
574 static void
575 stream_close_complete (GObject *source,
576 GAsyncResult *result,
577 gpointer user_data)
578 {
579 GTask *task = user_data;
580 CloseAsyncData *data;
581  
582 data = g_task_get_task_data (task);
583 data->pending--;
584  
585 if (G_IS_OUTPUT_STREAM (source))
586 {
587 GError *error = NULL;
588  
589 /* Match behaviour with the sync route and give precedent to the
590 * error returned from closing the output stream.
591 */
592 g_output_stream_close_finish (G_OUTPUT_STREAM (source), result, &error);
593 if (error)
594 {
595 if (data->error)
596 g_error_free (data->error);
597 data->error = error;
598 }
599 }
600 else
601 g_input_stream_close_finish (G_INPUT_STREAM (source), result, data->error ? NULL : &data->error);
602  
603 if (data->pending == 0)
604 {
605 if (data->error)
606 g_task_return_error (task, data->error);
607 else
608 g_task_return_boolean (task, TRUE);
609  
610 g_slice_free (CloseAsyncData, data);
611 g_object_unref (task);
612 }
613 }
614  
615 static void
616 g_io_stream_real_close_async (GIOStream *stream,
617 int io_priority,
618 GCancellable *cancellable,
619 GAsyncReadyCallback callback,
620 gpointer user_data)
621 {
622 GInputStream *input;
623 GOutputStream *output;
624 GTask *task;
625  
626 task = g_task_new (stream, cancellable, callback, user_data);
627 g_task_set_check_cancellable (task, FALSE);
628 g_task_set_priority (task, io_priority);
629  
630 input = g_io_stream_get_input_stream (stream);
631 output = g_io_stream_get_output_stream (stream);
632  
633 if (g_input_stream_async_close_is_via_threads (input) && g_output_stream_async_close_is_via_threads (output))
634 {
635 /* No sense in dispatching to the thread twice -- just do it all
636 * in one go.
637 */
638 g_task_run_in_thread (task, close_async_thread);
639 g_object_unref (task);
640 }
641 else
642 {
643 CloseAsyncData *data;
644  
645 /* We should avoid dispatching to another thread in case either
646 * object that would not do it for itself because it may not be
647 * threadsafe.
648 */
649 data = g_slice_new (CloseAsyncData);
650 data->error = NULL;
651 data->pending = 2;
652  
653 g_task_set_task_data (task, data, NULL);
654 g_input_stream_close_async (input, io_priority, cancellable, stream_close_complete, task);
655 g_output_stream_close_async (output, io_priority, cancellable, stream_close_complete, task);
656 }
657 }
658  
659 static gboolean
660 g_io_stream_real_close_finish (GIOStream *stream,
661 GAsyncResult *result,
662 GError **error)
663 {
664 g_return_val_if_fail (g_task_is_valid (result, stream), FALSE);
665  
666 return g_task_propagate_boolean (G_TASK (result), error);
667 }
668  
669 typedef struct
670 {
671 GIOStream *stream1;
672 GIOStream *stream2;
673 GIOStreamSpliceFlags flags;
674 gint io_priority;
675 GCancellable *cancellable;
676 gulong cancelled_id;
677 GCancellable *op1_cancellable;
678 GCancellable *op2_cancellable;
679 guint completed;
680 GError *error;
681 } SpliceContext;
682  
683 static void
684 splice_context_free (SpliceContext *ctx)
685 {
686 g_object_unref (ctx->stream1);
687 g_object_unref (ctx->stream2);
688 if (ctx->cancellable != NULL)
689 g_object_unref (ctx->cancellable);
690 g_object_unref (ctx->op1_cancellable);
691 g_object_unref (ctx->op2_cancellable);
692 g_clear_error (&ctx->error);
693 g_slice_free (SpliceContext, ctx);
694 }
695  
696 static void
697 splice_complete (GTask *task,
698 SpliceContext *ctx)
699 {
700 if (ctx->cancelled_id != 0)
701 g_cancellable_disconnect (ctx->cancellable, ctx->cancelled_id);
702 ctx->cancelled_id = 0;
703  
704 if (ctx->error != NULL)
705 {
706 g_task_return_error (task, ctx->error);
707 ctx->error = NULL;
708 }
709 else
710 g_task_return_boolean (task, TRUE);
711 }
712  
713 static void
714 splice_close_cb (GObject *iostream,
715 GAsyncResult *res,
716 gpointer user_data)
717 {
718 GTask *task = user_data;
719 SpliceContext *ctx = g_task_get_task_data (task);
720 GError *error = NULL;
721  
722 g_io_stream_close_finish (G_IO_STREAM (iostream), res, &error);
723  
724 ctx->completed++;
725  
726 /* Keep the first error that occurred */
727 if (error != NULL && ctx->error == NULL)
728 ctx->error = error;
729 else
730 g_clear_error (&error);
731  
732 /* If all operations are done, complete now */
733 if (ctx->completed == 4)
734 splice_complete (task, ctx);
735  
736 g_object_unref (task);
737 }
738  
739 static void
740 splice_cb (GObject *ostream,
741 GAsyncResult *res,
742 gpointer user_data)
743 {
744 GTask *task = user_data;
745 SpliceContext *ctx = g_task_get_task_data (task);
746 GError *error = NULL;
747  
748 g_output_stream_splice_finish (G_OUTPUT_STREAM (ostream), res, &error);
749  
750 ctx->completed++;
751  
752 /* ignore cancellation error if it was not requested by the user */
753 if (error != NULL &&
754 g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED) &&
755 (ctx->cancellable == NULL ||
756 !g_cancellable_is_cancelled (ctx->cancellable)))
757 g_clear_error (&error);
758  
759 /* Keep the first error that occurred */
760 if (error != NULL && ctx->error == NULL)
761 ctx->error = error;
762 else
763 g_clear_error (&error);
764  
765 if (ctx->completed == 1 &&
766 (ctx->flags & G_IO_STREAM_SPLICE_WAIT_FOR_BOTH) == 0)
767 {
768 /* We don't want to wait for the 2nd operation to finish, cancel it */
769 g_cancellable_cancel (ctx->op1_cancellable);
770 g_cancellable_cancel (ctx->op2_cancellable);
771 }
772 else if (ctx->completed == 2)
773 {
774 if (ctx->cancellable == NULL ||
775 !g_cancellable_is_cancelled (ctx->cancellable))
776 {
777 g_cancellable_reset (ctx->op1_cancellable);
778 g_cancellable_reset (ctx->op2_cancellable);
779 }
780  
781 /* Close the IO streams if needed */
782 if ((ctx->flags & G_IO_STREAM_SPLICE_CLOSE_STREAM1) != 0)
783 {
784 g_io_stream_close_async (ctx->stream1,
785 g_task_get_priority (task),
786 ctx->op1_cancellable,
787 splice_close_cb, g_object_ref (task));
788 }
789 else
790 ctx->completed++;
791  
792 if ((ctx->flags & G_IO_STREAM_SPLICE_CLOSE_STREAM2) != 0)
793 {
794 g_io_stream_close_async (ctx->stream2,
795 g_task_get_priority (task),
796 ctx->op2_cancellable,
797 splice_close_cb, g_object_ref (task));
798 }
799 else
800 ctx->completed++;
801  
802 /* If all operations are done, complete now */
803 if (ctx->completed == 4)
804 splice_complete (task, ctx);
805 }
806  
807 g_object_unref (task);
808 }
809  
810 static void
811 splice_cancelled_cb (GCancellable *cancellable,
812 GTask *task)
813 {
814 SpliceContext *ctx;
815  
816 ctx = g_task_get_task_data (task);
817 g_cancellable_cancel (ctx->op1_cancellable);
818 g_cancellable_cancel (ctx->op2_cancellable);
819 }
820  
821 /**
822 * g_io_stream_splice_async:
823 * @stream1: a #GIOStream.
824 * @stream2: a #GIOStream.
825 * @flags: a set of #GIOStreamSpliceFlags.
826 * @io_priority: the io priority of the request.
827 * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
828 * @callback: (scope async): a #GAsyncReadyCallback.
829 * @user_data: (closure): user data passed to @callback.
830 *
831 * Asyncronously splice the output stream of @stream1 to the input stream of
832 * @stream2, and splice the output stream of @stream2 to the input stream of
833 * @stream1.
834 *
835 * When the operation is finished @callback will be called.
836 * You can then call g_io_stream_splice_finish() to get the
837 * result of the operation.
838 *
839 * Since: 2.28
840 **/
841 void
842 g_io_stream_splice_async (GIOStream *stream1,
843 GIOStream *stream2,
844 GIOStreamSpliceFlags flags,
845 gint io_priority,
846 GCancellable *cancellable,
847 GAsyncReadyCallback callback,
848 gpointer user_data)
849 {
850 GTask *task;
851 SpliceContext *ctx;
852 GInputStream *istream;
853 GOutputStream *ostream;
854  
855 if (cancellable != NULL && g_cancellable_is_cancelled (cancellable))
856 {
857 g_task_report_new_error (NULL, callback, user_data,
858 g_io_stream_splice_async,
859 G_IO_ERROR, G_IO_ERROR_CANCELLED,
860 "Operation has been cancelled");
861 return;
862 }
863  
864 ctx = g_slice_new0 (SpliceContext);
865 ctx->stream1 = g_object_ref (stream1);
866 ctx->stream2 = g_object_ref (stream2);
867 ctx->flags = flags;
868 ctx->op1_cancellable = g_cancellable_new ();
869 ctx->op2_cancellable = g_cancellable_new ();
870 ctx->completed = 0;
871  
872 task = g_task_new (NULL, cancellable, callback, user_data);
873 g_task_set_task_data (task, ctx, (GDestroyNotify) splice_context_free);
874  
875 if (cancellable != NULL)
876 {
877 ctx->cancellable = g_object_ref (cancellable);
878 ctx->cancelled_id = g_cancellable_connect (cancellable,
879 G_CALLBACK (splice_cancelled_cb), g_object_ref (task),
880 g_object_unref);
881 }
882  
883 istream = g_io_stream_get_input_stream (stream1);
884 ostream = g_io_stream_get_output_stream (stream2);
885 g_output_stream_splice_async (ostream, istream, G_OUTPUT_STREAM_SPLICE_NONE,
886 io_priority, ctx->op1_cancellable, splice_cb,
887 g_object_ref (task));
888  
889 istream = g_io_stream_get_input_stream (stream2);
890 ostream = g_io_stream_get_output_stream (stream1);
891 g_output_stream_splice_async (ostream, istream, G_OUTPUT_STREAM_SPLICE_NONE,
892 io_priority, ctx->op2_cancellable, splice_cb,
893 g_object_ref (task));
894  
895 g_object_unref (task);
896 }
897  
898 /**
899 * g_io_stream_splice_finish:
900 * @result: a #GAsyncResult.
901 * @error: a #GError location to store the error occurring, or %NULL to
902 * ignore.
903 *
904 * Finishes an asynchronous io stream splice operation.
905 *
906 * Returns: %TRUE on success, %FALSE otherwise.
907 *
908 * Since: 2.28
909 **/
910 gboolean
911 g_io_stream_splice_finish (GAsyncResult *result,
912 GError **error)
913 {
914 g_return_val_if_fail (g_task_is_valid (result, NULL), FALSE);
915  
916 return g_task_propagate_boolean (G_TASK (result), error);
917 }