1/* GIO - GLib Input, IO and Streaming Library
2 *
3 * Copyright (C) 2006-2007 Red Hat, Inc.
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2.1 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General
16 * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
17 *
18 * Author: Alexander Larsson <alexl@redhat.com>
19 */
20
21#include "config.h"
22
23#include <glib.h>
24#include <gfileiostream.h>
25#include <gseekable.h>
26#include "gasyncresult.h"
27#include "gtask.h"
28#include "gcancellable.h"
29#include "gioerror.h"
30#include "gfileoutputstream.h"
31#include "glibintl.h"
32
33
34/**
35 * SECTION:gfileiostream
36 * @short_description: File read and write streaming operations
37 * @include: gio/gio.h
38 * @see_also: #GIOStream, #GFileInputStream, #GFileOutputStream, #GSeekable
39 *
40 * GFileIOStream provides io streams that both read and write to the same
41 * file handle.
42 *
43 * GFileIOStream implements #GSeekable, which allows the io
44 * stream to jump to arbitrary positions in the file and to truncate
45 * the file, provided the filesystem of the file supports these
46 * operations.
47 *
48 * To find the position of a file io stream, use
49 * g_seekable_tell().
50 *
51 * To find out if a file io stream supports seeking, use g_seekable_can_seek().
52 * To position a file io stream, use g_seekable_seek().
53 * To find out if a file io stream supports truncating, use
54 * g_seekable_can_truncate(). To truncate a file io
55 * stream, use g_seekable_truncate().
56 *
57 * The default implementation of all the #GFileIOStream operations
58 * and the implementation of #GSeekable just call into the same operations
59 * on the output stream.
60 * Since: 2.22
61 **/
62
63static void g_file_io_stream_seekable_iface_init (GSeekableIface *iface);
64static goffset g_file_io_stream_seekable_tell (GSeekable *seekable);
65static gboolean g_file_io_stream_seekable_can_seek (GSeekable *seekable);
66static gboolean g_file_io_stream_seekable_seek (GSeekable *seekable,
67 goffset offset,
68 GSeekType type,
69 GCancellable *cancellable,
70 GError **error);
71static gboolean g_file_io_stream_seekable_can_truncate (GSeekable *seekable);
72static gboolean g_file_io_stream_seekable_truncate (GSeekable *seekable,
73 goffset offset,
74 GCancellable *cancellable,
75 GError **error);
76static void g_file_io_stream_real_query_info_async (GFileIOStream *stream,
77 const char *attributes,
78 int io_priority,
79 GCancellable *cancellable,
80 GAsyncReadyCallback callback,
81 gpointer user_data);
82static GFileInfo *g_file_io_stream_real_query_info_finish (GFileIOStream *stream,
83 GAsyncResult *result,
84 GError **error);
85
86struct _GFileIOStreamPrivate {
87 GAsyncReadyCallback outstanding_callback;
88};
89
90G_DEFINE_TYPE_WITH_CODE (GFileIOStream, g_file_io_stream, G_TYPE_IO_STREAM,
91 G_ADD_PRIVATE (GFileIOStream)
92 G_IMPLEMENT_INTERFACE (G_TYPE_SEEKABLE,
93 g_file_io_stream_seekable_iface_init))
94
95static void
96g_file_io_stream_seekable_iface_init (GSeekableIface *iface)
97{
98 iface->tell = g_file_io_stream_seekable_tell;
99 iface->can_seek = g_file_io_stream_seekable_can_seek;
100 iface->seek = g_file_io_stream_seekable_seek;
101 iface->can_truncate = g_file_io_stream_seekable_can_truncate;
102 iface->truncate_fn = g_file_io_stream_seekable_truncate;
103}
104
105static void
106g_file_io_stream_init (GFileIOStream *stream)
107{
108 stream->priv = g_file_io_stream_get_instance_private (self: stream);
109}
110
111/**
112 * g_file_io_stream_query_info:
113 * @stream: a #GFileIOStream.
114 * @attributes: a file attribute query string.
115 * @cancellable: (nullable): optional #GCancellable object, %NULL to ignore.
116 * @error: a #GError, %NULL to ignore.
117 *
118 * Queries a file io stream for the given @attributes.
119 * This function blocks while querying the stream. For the asynchronous
120 * version of this function, see g_file_io_stream_query_info_async().
121 * While the stream is blocked, the stream will set the pending flag
122 * internally, and any other operations on the stream will fail with
123 * %G_IO_ERROR_PENDING.
124 *
125 * Can fail if the stream was already closed (with @error being set to
126 * %G_IO_ERROR_CLOSED), the stream has pending operations (with @error being
127 * set to %G_IO_ERROR_PENDING), or if querying info is not supported for
128 * the stream's interface (with @error being set to %G_IO_ERROR_NOT_SUPPORTED). I
129 * all cases of failure, %NULL will be returned.
130 *
131 * If @cancellable is not %NULL, then the operation can be cancelled by
132 * triggering the cancellable object from another thread. If the operation
133 * was cancelled, the error %G_IO_ERROR_CANCELLED will be set, and %NULL will
134 * be returned.
135 *
136 * Returns: (transfer full): a #GFileInfo for the @stream, or %NULL on error.
137 *
138 * Since: 2.22
139 **/
140GFileInfo *
141g_file_io_stream_query_info (GFileIOStream *stream,
142 const char *attributes,
143 GCancellable *cancellable,
144 GError **error)
145{
146 GFileIOStreamClass *class;
147 GIOStream *io_stream;
148 GFileInfo *info;
149
150 g_return_val_if_fail (G_IS_FILE_IO_STREAM (stream), NULL);
151
152 io_stream = G_IO_STREAM (stream);
153
154 if (!g_io_stream_set_pending (stream: io_stream, error))
155 return NULL;
156
157 info = NULL;
158
159 if (cancellable)
160 g_cancellable_push_current (cancellable);
161
162 class = G_FILE_IO_STREAM_GET_CLASS (stream);
163 if (class->query_info)
164 info = class->query_info (stream, attributes, cancellable, error);
165 else
166 g_set_error_literal (err: error, G_IO_ERROR, code: G_IO_ERROR_NOT_SUPPORTED,
167 _("Stream doesn’t support query_info"));
168
169 if (cancellable)
170 g_cancellable_pop_current (cancellable);
171
172 g_io_stream_clear_pending (stream: io_stream);
173
174 return info;
175}
176
177static void
178async_ready_callback_wrapper (GObject *source_object,
179 GAsyncResult *res,
180 gpointer user_data)
181{
182 GFileIOStream *stream = G_FILE_IO_STREAM (source_object);
183
184 g_io_stream_clear_pending (G_IO_STREAM (stream));
185 if (stream->priv->outstanding_callback)
186 (*stream->priv->outstanding_callback) (source_object, res, user_data);
187 g_object_unref (object: stream);
188}
189
190/**
191 * g_file_io_stream_query_info_async:
192 * @stream: a #GFileIOStream.
193 * @attributes: a file attribute query string.
194 * @io_priority: the [I/O priority][gio-GIOScheduler] of the request
195 * @cancellable: (nullable): optional #GCancellable object, %NULL to ignore.
196 * @callback: (scope async): callback to call when the request is satisfied
197 * @user_data: (closure): the data to pass to callback function
198 *
199 * Asynchronously queries the @stream for a #GFileInfo. When completed,
200 * @callback will be called with a #GAsyncResult which can be used to
201 * finish the operation with g_file_io_stream_query_info_finish().
202 *
203 * For the synchronous version of this function, see
204 * g_file_io_stream_query_info().
205 *
206 * Since: 2.22
207 **/
208void
209g_file_io_stream_query_info_async (GFileIOStream *stream,
210 const char *attributes,
211 int io_priority,
212 GCancellable *cancellable,
213 GAsyncReadyCallback callback,
214 gpointer user_data)
215{
216 GFileIOStreamClass *klass;
217 GIOStream *io_stream;
218 GError *error = NULL;
219
220 g_return_if_fail (G_IS_FILE_IO_STREAM (stream));
221
222 io_stream = G_IO_STREAM (stream);
223
224 if (!g_io_stream_set_pending (stream: io_stream, error: &error))
225 {
226 g_task_report_error (source_object: stream, callback, callback_data: user_data,
227 source_tag: g_file_io_stream_query_info_async,
228 error);
229 return;
230 }
231
232 klass = G_FILE_IO_STREAM_GET_CLASS (stream);
233
234 stream->priv->outstanding_callback = callback;
235 g_object_ref (stream);
236 klass->query_info_async (stream, attributes, io_priority, cancellable,
237 async_ready_callback_wrapper, user_data);
238}
239
240/**
241 * g_file_io_stream_query_info_finish:
242 * @stream: a #GFileIOStream.
243 * @result: a #GAsyncResult.
244 * @error: a #GError, %NULL to ignore.
245 *
246 * Finalizes the asynchronous query started
247 * by g_file_io_stream_query_info_async().
248 *
249 * Returns: (transfer full): A #GFileInfo for the finished query.
250 *
251 * Since: 2.22
252 **/
253GFileInfo *
254g_file_io_stream_query_info_finish (GFileIOStream *stream,
255 GAsyncResult *result,
256 GError **error)
257{
258 GFileIOStreamClass *class;
259
260 g_return_val_if_fail (G_IS_FILE_IO_STREAM (stream), NULL);
261 g_return_val_if_fail (G_IS_ASYNC_RESULT (result), NULL);
262
263 if (g_async_result_legacy_propagate_error (res: result, error))
264 return NULL;
265 else if (g_async_result_is_tagged (res: result, source_tag: g_file_io_stream_query_info_async))
266 return g_task_propagate_pointer (G_TASK (result), error);
267
268 class = G_FILE_IO_STREAM_GET_CLASS (stream);
269 return class->query_info_finish (stream, result, error);
270}
271
272/**
273 * g_file_io_stream_get_etag:
274 * @stream: a #GFileIOStream.
275 *
276 * Gets the entity tag for the file when it has been written.
277 * This must be called after the stream has been written
278 * and closed, as the etag can change while writing.
279 *
280 * Returns: (nullable) (transfer full): the entity tag for the stream.
281 *
282 * Since: 2.22
283 **/
284char *
285g_file_io_stream_get_etag (GFileIOStream *stream)
286{
287 GFileIOStreamClass *class;
288 GIOStream *io_stream;
289 char *etag;
290
291 g_return_val_if_fail (G_IS_FILE_IO_STREAM (stream), NULL);
292
293 io_stream = G_IO_STREAM (stream);
294
295 if (!g_io_stream_is_closed (stream: io_stream))
296 {
297 g_warning ("stream is not closed yet, can't get etag");
298 return NULL;
299 }
300
301 etag = NULL;
302
303 class = G_FILE_IO_STREAM_GET_CLASS (stream);
304 if (class->get_etag)
305 etag = class->get_etag (stream);
306
307 return etag;
308}
309
310static goffset
311g_file_io_stream_tell (GFileIOStream *stream)
312{
313 GFileIOStreamClass *class;
314 goffset offset;
315
316 g_return_val_if_fail (G_IS_FILE_IO_STREAM (stream), 0);
317
318 class = G_FILE_IO_STREAM_GET_CLASS (stream);
319
320 offset = 0;
321 if (class->tell)
322 offset = class->tell (stream);
323
324 return offset;
325}
326
327static goffset
328g_file_io_stream_seekable_tell (GSeekable *seekable)
329{
330 return g_file_io_stream_tell (G_FILE_IO_STREAM (seekable));
331}
332
333static gboolean
334g_file_io_stream_can_seek (GFileIOStream *stream)
335{
336 GFileIOStreamClass *class;
337 gboolean can_seek;
338
339 g_return_val_if_fail (G_IS_FILE_IO_STREAM (stream), FALSE);
340
341 class = G_FILE_IO_STREAM_GET_CLASS (stream);
342
343 can_seek = FALSE;
344 if (class->seek)
345 {
346 can_seek = TRUE;
347 if (class->can_seek)
348 can_seek = class->can_seek (stream);
349 }
350
351 return can_seek;
352}
353
354static gboolean
355g_file_io_stream_seekable_can_seek (GSeekable *seekable)
356{
357 return g_file_io_stream_can_seek (G_FILE_IO_STREAM (seekable));
358}
359
360static gboolean
361g_file_io_stream_seek (GFileIOStream *stream,
362 goffset offset,
363 GSeekType type,
364 GCancellable *cancellable,
365 GError **error)
366{
367 GFileIOStreamClass *class;
368 GIOStream *io_stream;
369 gboolean res;
370
371 g_return_val_if_fail (G_IS_FILE_IO_STREAM (stream), FALSE);
372
373 io_stream = G_IO_STREAM (stream);
374 class = G_FILE_IO_STREAM_GET_CLASS (stream);
375
376 if (!class->seek)
377 {
378 g_set_error_literal (err: error, G_IO_ERROR, code: G_IO_ERROR_NOT_SUPPORTED,
379 _("Seek not supported on stream"));
380 return FALSE;
381 }
382
383 if (!g_io_stream_set_pending (stream: io_stream, error))
384 return FALSE;
385
386 if (cancellable)
387 g_cancellable_push_current (cancellable);
388
389 res = class->seek (stream, offset, type, cancellable, error);
390
391 if (cancellable)
392 g_cancellable_pop_current (cancellable);
393
394 g_io_stream_clear_pending (stream: io_stream);
395
396 return res;
397}
398
399static gboolean
400g_file_io_stream_seekable_seek (GSeekable *seekable,
401 goffset offset,
402 GSeekType type,
403 GCancellable *cancellable,
404 GError **error)
405{
406 return g_file_io_stream_seek (G_FILE_IO_STREAM (seekable),
407 offset, type, cancellable, error);
408}
409
410static gboolean
411g_file_io_stream_can_truncate (GFileIOStream *stream)
412{
413 GFileIOStreamClass *class;
414 gboolean can_truncate;
415
416 g_return_val_if_fail (G_IS_FILE_IO_STREAM (stream), FALSE);
417
418 class = G_FILE_IO_STREAM_GET_CLASS (stream);
419
420 can_truncate = FALSE;
421 if (class->truncate_fn)
422 {
423 can_truncate = TRUE;
424 if (class->can_truncate)
425 can_truncate = class->can_truncate (stream);
426 }
427
428 return can_truncate;
429}
430
431static gboolean
432g_file_io_stream_seekable_can_truncate (GSeekable *seekable)
433{
434 return g_file_io_stream_can_truncate (G_FILE_IO_STREAM (seekable));
435}
436
437static gboolean
438g_file_io_stream_truncate (GFileIOStream *stream,
439 goffset size,
440 GCancellable *cancellable,
441 GError **error)
442{
443 GFileIOStreamClass *class;
444 GIOStream *io_stream;
445 gboolean res;
446
447 g_return_val_if_fail (G_IS_FILE_IO_STREAM (stream), FALSE);
448
449 io_stream = G_IO_STREAM (stream);
450 class = G_FILE_IO_STREAM_GET_CLASS (stream);
451
452 if (!class->truncate_fn)
453 {
454 g_set_error_literal (err: error, G_IO_ERROR, code: G_IO_ERROR_NOT_SUPPORTED,
455 _("Truncate not supported on stream"));
456 return FALSE;
457 }
458
459 if (!g_io_stream_set_pending (stream: io_stream, error))
460 return FALSE;
461
462 if (cancellable)
463 g_cancellable_push_current (cancellable);
464
465 res = class->truncate_fn (stream, size, cancellable, error);
466
467 if (cancellable)
468 g_cancellable_pop_current (cancellable);
469
470 g_io_stream_clear_pending (stream: io_stream);
471
472 return res;
473}
474
475static gboolean
476g_file_io_stream_seekable_truncate (GSeekable *seekable,
477 goffset size,
478 GCancellable *cancellable,
479 GError **error)
480{
481 return g_file_io_stream_truncate (G_FILE_IO_STREAM (seekable),
482 size, cancellable, error);
483}
484/*****************************************************
485 * Default implementations based on output stream *
486 *****************************************************/
487
488static goffset
489g_file_io_stream_real_tell (GFileIOStream *stream)
490{
491 GOutputStream *out;
492 GSeekable *seekable;
493
494 out = g_io_stream_get_output_stream (G_IO_STREAM (stream));
495 seekable = G_SEEKABLE (out);
496
497 return g_seekable_tell (seekable);
498}
499
500static gboolean
501g_file_io_stream_real_can_seek (GFileIOStream *stream)
502{
503 GOutputStream *out;
504 GSeekable *seekable;
505
506 out = g_io_stream_get_output_stream (G_IO_STREAM (stream));
507 seekable = G_SEEKABLE (out);
508
509 return g_seekable_can_seek (seekable);
510}
511
512static gboolean
513g_file_io_stream_real_seek (GFileIOStream *stream,
514 goffset offset,
515 GSeekType type,
516 GCancellable *cancellable,
517 GError **error)
518{
519 GOutputStream *out;
520 GSeekable *seekable;
521
522 out = g_io_stream_get_output_stream (G_IO_STREAM (stream));
523 seekable = G_SEEKABLE (out);
524
525 return g_seekable_seek (seekable, offset, type, cancellable, error);
526}
527
528static gboolean
529g_file_io_stream_real_can_truncate (GFileIOStream *stream)
530{
531 GOutputStream *out;
532 GSeekable *seekable;
533
534 out = g_io_stream_get_output_stream (G_IO_STREAM (stream));
535 seekable = G_SEEKABLE (out);
536
537 return g_seekable_can_truncate (seekable);
538}
539
540static gboolean
541g_file_io_stream_real_truncate_fn (GFileIOStream *stream,
542 goffset size,
543 GCancellable *cancellable,
544 GError **error)
545{
546 GOutputStream *out;
547 GSeekable *seekable;
548
549 out = g_io_stream_get_output_stream (G_IO_STREAM (stream));
550 seekable = G_SEEKABLE (out);
551
552 return g_seekable_truncate (seekable, offset: size, cancellable, error);
553}
554
555static char *
556g_file_io_stream_real_get_etag (GFileIOStream *stream)
557{
558 GOutputStream *out;
559 GFileOutputStream *file_out;
560
561 out = g_io_stream_get_output_stream (G_IO_STREAM (stream));
562 file_out = G_FILE_OUTPUT_STREAM (out);
563
564 return g_file_output_stream_get_etag (stream: file_out);
565}
566
567static GFileInfo *
568g_file_io_stream_real_query_info (GFileIOStream *stream,
569 const char *attributes,
570 GCancellable *cancellable,
571 GError **error)
572{
573 GOutputStream *out;
574 GFileOutputStream *file_out;
575
576 out = g_io_stream_get_output_stream (G_IO_STREAM (stream));
577 file_out = G_FILE_OUTPUT_STREAM (out);
578
579 return g_file_output_stream_query_info (stream: file_out,
580 attributes, cancellable, error);
581}
582
583typedef struct {
584 GObject *object;
585 GAsyncReadyCallback callback;
586 gpointer user_data;
587} AsyncOpWrapper;
588
589static AsyncOpWrapper *
590async_op_wrapper_new (gpointer object,
591 GAsyncReadyCallback callback,
592 gpointer user_data)
593{
594 AsyncOpWrapper *data;
595
596 data = g_new0 (AsyncOpWrapper, 1);
597 data->object = g_object_ref (object);
598 data->callback = callback;
599 data->user_data = user_data;
600
601 return data;
602}
603
604static void
605async_op_wrapper_callback (GObject *source_object,
606 GAsyncResult *res,
607 gpointer user_data)
608{
609 AsyncOpWrapper *data = user_data;
610 data->callback (data->object, res, data->user_data);
611 g_object_unref (object: data->object);
612 g_free (mem: data);
613}
614
615static void
616g_file_io_stream_real_query_info_async (GFileIOStream *stream,
617 const char *attributes,
618 int io_priority,
619 GCancellable *cancellable,
620 GAsyncReadyCallback callback,
621 gpointer user_data)
622{
623 GOutputStream *out;
624 GFileOutputStream *file_out;
625 AsyncOpWrapper *data;
626
627 out = g_io_stream_get_output_stream (G_IO_STREAM (stream));
628 file_out = G_FILE_OUTPUT_STREAM (out);
629
630 data = async_op_wrapper_new (object: stream, callback, user_data);
631 g_file_output_stream_query_info_async (stream: file_out,
632 attributes, io_priority,
633 cancellable, callback: async_op_wrapper_callback, user_data: data);
634}
635
636static GFileInfo *
637g_file_io_stream_real_query_info_finish (GFileIOStream *stream,
638 GAsyncResult *res,
639 GError **error)
640{
641 GOutputStream *out;
642 GFileOutputStream *file_out;
643
644 out = g_io_stream_get_output_stream (G_IO_STREAM (stream));
645 file_out = G_FILE_OUTPUT_STREAM (out);
646
647 return g_file_output_stream_query_info_finish (stream: file_out, result: res, error);
648}
649
650static void
651g_file_io_stream_class_init (GFileIOStreamClass *klass)
652{
653 klass->tell = g_file_io_stream_real_tell;
654 klass->can_seek = g_file_io_stream_real_can_seek;
655 klass->seek = g_file_io_stream_real_seek;
656 klass->can_truncate = g_file_io_stream_real_can_truncate;
657 klass->truncate_fn = g_file_io_stream_real_truncate_fn;
658 klass->query_info = g_file_io_stream_real_query_info;
659 klass->query_info_async = g_file_io_stream_real_query_info_async;
660 klass->query_info_finish = g_file_io_stream_real_query_info_finish;
661 klass->get_etag = g_file_io_stream_real_get_etag;
662}
663

source code of gtk/subprojects/glib/gio/gfileiostream.c