1 /* GIO - GLib Input, Output and Streaming Library
3 * Copyright (C) 2006-2007 Red Hat, Inc.
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 of the License, or (at your option) any later version.
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.
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/>.
18 * Author: Alexander Larsson <alexl@redhat.com>
24 #include <gfileoutputstream.h>
25 #include <gseekable.h>
26 #include "gasyncresult.h"
28 #include "gcancellable.h"
34 * SECTION:gfileoutputstream
35 * @short_description: File output streaming operations
37 * @see_also: #GOutputStream, #GDataOutputStream, #GSeekable
39 * GFileOutputStream provides output streams that write their
42 * GFileOutputStream implements #GSeekable, which allows the output
43 * stream to jump to arbitrary positions in the file and to truncate
44 * the file, provided the filesystem of the file supports these
47 * To find the position of a file output stream, use g_seekable_tell().
48 * To find out if a file output stream supports seeking, use
49 * g_seekable_can_seek().To position a file output stream, use
50 * g_seekable_seek(). To find out if a file output stream supports
51 * truncating, use g_seekable_can_truncate(). To truncate a file output
52 * stream, use g_seekable_truncate().
55 static void g_file_output_stream_seekable_iface_init (GSeekableIface *iface);
56 static goffset g_file_output_stream_seekable_tell (GSeekable *seekable);
57 static gboolean g_file_output_stream_seekable_can_seek (GSeekable *seekable);
58 static gboolean g_file_output_stream_seekable_seek (GSeekable *seekable,
61 GCancellable *cancellable,
63 static gboolean g_file_output_stream_seekable_can_truncate (GSeekable *seekable);
64 static gboolean g_file_output_stream_seekable_truncate (GSeekable *seekable,
66 GCancellable *cancellable,
68 static void g_file_output_stream_real_query_info_async (GFileOutputStream *stream,
69 const char *attributes,
71 GCancellable *cancellable,
72 GAsyncReadyCallback callback,
74 static GFileInfo *g_file_output_stream_real_query_info_finish (GFileOutputStream *stream,
78 struct _GFileOutputStreamPrivate {
79 GAsyncReadyCallback outstanding_callback;
82 G_DEFINE_TYPE_WITH_CODE (GFileOutputStream, g_file_output_stream, G_TYPE_OUTPUT_STREAM,
83 G_ADD_PRIVATE (GFileOutputStream)
84 G_IMPLEMENT_INTERFACE (G_TYPE_SEEKABLE,
85 g_file_output_stream_seekable_iface_init));
88 g_file_output_stream_class_init (GFileOutputStreamClass *klass)
90 klass->query_info_async = g_file_output_stream_real_query_info_async;
91 klass->query_info_finish = g_file_output_stream_real_query_info_finish;
95 g_file_output_stream_seekable_iface_init (GSeekableIface *iface)
97 iface->tell = g_file_output_stream_seekable_tell;
98 iface->can_seek = g_file_output_stream_seekable_can_seek;
99 iface->seek = g_file_output_stream_seekable_seek;
100 iface->can_truncate = g_file_output_stream_seekable_can_truncate;
101 iface->truncate_fn = g_file_output_stream_seekable_truncate;
105 g_file_output_stream_init (GFileOutputStream *stream)
107 stream->priv = g_file_output_stream_get_instance_private (stream);
111 * g_file_output_stream_query_info:
112 * @stream: a #GFileOutputStream.
113 * @attributes: a file attribute query string.
114 * @cancellable: optional #GCancellable object, %NULL to ignore.
115 * @error: a #GError, %NULL to ignore.
117 * Queries a file output stream for the given @attributes.
118 * This function blocks while querying the stream. For the asynchronous
119 * version of this function, see g_file_output_stream_query_info_async().
120 * While the stream is blocked, the stream will set the pending flag
121 * internally, and any other operations on the stream will fail with
122 * %G_IO_ERROR_PENDING.
124 * Can fail if the stream was already closed (with @error being set to
125 * %G_IO_ERROR_CLOSED), the stream has pending operations (with @error being
126 * set to %G_IO_ERROR_PENDING), or if querying info is not supported for
127 * the stream's interface (with @error being set to %G_IO_ERROR_NOT_SUPPORTED). In
128 * all cases of failure, %NULL will be returned.
130 * If @cancellable is not %NULL, then the operation can be cancelled by
131 * triggering the cancellable object from another thread. If the operation
132 * was cancelled, the error %G_IO_ERROR_CANCELLED will be set, and %NULL will
135 * Returns: (transfer full): a #GFileInfo for the @stream, or %NULL on error.
138 g_file_output_stream_query_info (GFileOutputStream *stream,
139 const char *attributes,
140 GCancellable *cancellable,
143 GFileOutputStreamClass *class;
144 GOutputStream *output_stream;
147 g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), NULL);
149 output_stream = G_OUTPUT_STREAM (stream);
151 if (!g_output_stream_set_pending (output_stream, error))
157 g_cancellable_push_current (cancellable);
159 class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
160 if (class->query_info)
161 info = class->query_info (stream, attributes, cancellable, error);
163 g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
164 _("Stream doesn't support query_info"));
167 g_cancellable_pop_current (cancellable);
169 g_output_stream_clear_pending (output_stream);
175 async_ready_callback_wrapper (GObject *source_object,
179 GFileOutputStream *stream = G_FILE_OUTPUT_STREAM (source_object);
181 g_output_stream_clear_pending (G_OUTPUT_STREAM (stream));
182 if (stream->priv->outstanding_callback)
183 (*stream->priv->outstanding_callback) (source_object, res, user_data);
184 g_object_unref (stream);
188 * g_file_output_stream_query_info_async:
189 * @stream: a #GFileOutputStream.
190 * @attributes: a file attribute query string.
191 * @io_priority: the <link linkend="gio-GIOScheduler">I/O priority</link>
193 * @cancellable: optional #GCancellable object, %NULL to ignore.
194 * @callback: callback to call when the request is satisfied
195 * @user_data: the data to pass to callback function
197 * Asynchronously queries the @stream for a #GFileInfo. When completed,
198 * @callback will be called with a #GAsyncResult which can be used to
199 * finish the operation with g_file_output_stream_query_info_finish().
201 * For the synchronous version of this function, see
202 * g_file_output_stream_query_info().
206 g_file_output_stream_query_info_async (GFileOutputStream *stream,
207 const char *attributes,
209 GCancellable *cancellable,
210 GAsyncReadyCallback callback,
213 GFileOutputStreamClass *klass;
214 GOutputStream *output_stream;
215 GError *error = NULL;
217 g_return_if_fail (G_IS_FILE_OUTPUT_STREAM (stream));
219 output_stream = G_OUTPUT_STREAM (stream);
221 if (!g_output_stream_set_pending (output_stream, &error))
223 g_task_report_error (stream, callback, user_data,
224 g_file_output_stream_query_info_async,
229 klass = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
231 stream->priv->outstanding_callback = callback;
232 g_object_ref (stream);
233 klass->query_info_async (stream, attributes, io_priority, cancellable,
234 async_ready_callback_wrapper, user_data);
238 * g_file_output_stream_query_info_finish:
239 * @stream: a #GFileOutputStream.
240 * @result: a #GAsyncResult.
241 * @error: a #GError, %NULL to ignore.
243 * Finalizes the asynchronous query started
244 * by g_file_output_stream_query_info_async().
246 * Returns: (transfer full): A #GFileInfo for the finished query.
249 g_file_output_stream_query_info_finish (GFileOutputStream *stream,
250 GAsyncResult *result,
253 GFileOutputStreamClass *class;
255 g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), NULL);
256 g_return_val_if_fail (G_IS_ASYNC_RESULT (result), NULL);
258 if (g_async_result_legacy_propagate_error (result, error))
260 else if (g_async_result_is_tagged (result, g_file_output_stream_query_info_async))
261 return g_task_propagate_pointer (G_TASK (result), error);
263 class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
264 return class->query_info_finish (stream, result, error);
268 * g_file_output_stream_get_etag:
269 * @stream: a #GFileOutputStream.
271 * Gets the entity tag for the file when it has been written.
272 * This must be called after the stream has been written
273 * and closed, as the etag can change while writing.
275 * Returns: the entity tag for the stream.
278 g_file_output_stream_get_etag (GFileOutputStream *stream)
280 GFileOutputStreamClass *class;
281 GOutputStream *output_stream;
284 g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), NULL);
286 output_stream = G_OUTPUT_STREAM (stream);
288 if (!g_output_stream_is_closed (output_stream))
290 g_warning ("stream is not closed yet, can't get etag");
296 class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
298 etag = class->get_etag (stream);
304 g_file_output_stream_tell (GFileOutputStream *stream)
306 GFileOutputStreamClass *class;
309 g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), 0);
311 class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
315 offset = class->tell (stream);
321 g_file_output_stream_seekable_tell (GSeekable *seekable)
323 return g_file_output_stream_tell (G_FILE_OUTPUT_STREAM (seekable));
327 g_file_output_stream_can_seek (GFileOutputStream *stream)
329 GFileOutputStreamClass *class;
332 g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
334 class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
341 can_seek = class->can_seek (stream);
348 g_file_output_stream_seekable_can_seek (GSeekable *seekable)
350 return g_file_output_stream_can_seek (G_FILE_OUTPUT_STREAM (seekable));
354 g_file_output_stream_seek (GFileOutputStream *stream,
357 GCancellable *cancellable,
360 GFileOutputStreamClass *class;
361 GOutputStream *output_stream;
364 g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
366 output_stream = G_OUTPUT_STREAM (stream);
367 class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
371 g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
372 _("Seek not supported on stream"));
376 if (!g_output_stream_set_pending (output_stream, error))
380 g_cancellable_push_current (cancellable);
382 res = class->seek (stream, offset, type, cancellable, error);
385 g_cancellable_pop_current (cancellable);
387 g_output_stream_clear_pending (output_stream);
393 g_file_output_stream_seekable_seek (GSeekable *seekable,
396 GCancellable *cancellable,
399 return g_file_output_stream_seek (G_FILE_OUTPUT_STREAM (seekable),
400 offset, type, cancellable, error);
404 g_file_output_stream_can_truncate (GFileOutputStream *stream)
406 GFileOutputStreamClass *class;
407 gboolean can_truncate;
409 g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
411 class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
413 can_truncate = FALSE;
414 if (class->truncate_fn)
417 if (class->can_truncate)
418 can_truncate = class->can_truncate (stream);
425 g_file_output_stream_seekable_can_truncate (GSeekable *seekable)
427 return g_file_output_stream_can_truncate (G_FILE_OUTPUT_STREAM (seekable));
431 g_file_output_stream_truncate (GFileOutputStream *stream,
433 GCancellable *cancellable,
436 GFileOutputStreamClass *class;
437 GOutputStream *output_stream;
440 g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
442 output_stream = G_OUTPUT_STREAM (stream);
443 class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
445 if (!class->truncate_fn)
447 g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
448 _("Truncate not supported on stream"));
452 if (!g_output_stream_set_pending (output_stream, error))
456 g_cancellable_push_current (cancellable);
458 res = class->truncate_fn (stream, size, cancellable, error);
461 g_cancellable_pop_current (cancellable);
463 g_output_stream_clear_pending (output_stream);
469 g_file_output_stream_seekable_truncate (GSeekable *seekable,
471 GCancellable *cancellable,
474 return g_file_output_stream_truncate (G_FILE_OUTPUT_STREAM (seekable),
475 size, cancellable, error);
477 /********************************************
478 * Default implementation of async ops *
479 ********************************************/
482 query_info_async_thread (GTask *task,
483 gpointer source_object,
485 GCancellable *cancellable)
487 GFileOutputStream *stream = source_object;
488 const char *attributes = task_data;
489 GFileOutputStreamClass *class;
490 GError *error = NULL;
491 GFileInfo *info = NULL;
493 class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
494 if (class->query_info)
495 info = class->query_info (stream, attributes, cancellable, &error);
497 g_set_error_literal (&error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
498 _("Stream doesn't support query_info"));
501 g_task_return_error (task, error);
503 g_task_return_pointer (task, info, g_object_unref);
507 g_file_output_stream_real_query_info_async (GFileOutputStream *stream,
508 const char *attributes,
510 GCancellable *cancellable,
511 GAsyncReadyCallback callback,
516 task = g_task_new (stream, cancellable, callback, user_data);
517 g_task_set_task_data (task, g_strdup (attributes), g_free);
518 g_task_set_priority (task, io_priority);
520 g_task_run_in_thread (task, query_info_async_thread);
521 g_object_unref (task);
525 g_file_output_stream_real_query_info_finish (GFileOutputStream *stream,
529 g_return_val_if_fail (g_task_is_valid (res, stream), NULL);
531 return g_task_propagate_pointer (G_TASK (res), error);