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 [I/O priority][gio-GIOScheduler] of the request
192 * @cancellable: optional #GCancellable object, %NULL to ignore.
193 * @callback: callback to call when the request is satisfied
194 * @user_data: the data to pass to callback function
196 * Asynchronously queries the @stream for a #GFileInfo. When completed,
197 * @callback will be called with a #GAsyncResult which can be used to
198 * finish the operation with g_file_output_stream_query_info_finish().
200 * For the synchronous version of this function, see
201 * g_file_output_stream_query_info().
205 g_file_output_stream_query_info_async (GFileOutputStream *stream,
206 const char *attributes,
208 GCancellable *cancellable,
209 GAsyncReadyCallback callback,
212 GFileOutputStreamClass *klass;
213 GOutputStream *output_stream;
214 GError *error = NULL;
216 g_return_if_fail (G_IS_FILE_OUTPUT_STREAM (stream));
218 output_stream = G_OUTPUT_STREAM (stream);
220 if (!g_output_stream_set_pending (output_stream, &error))
222 g_task_report_error (stream, callback, user_data,
223 g_file_output_stream_query_info_async,
228 klass = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
230 stream->priv->outstanding_callback = callback;
231 g_object_ref (stream);
232 klass->query_info_async (stream, attributes, io_priority, cancellable,
233 async_ready_callback_wrapper, user_data);
237 * g_file_output_stream_query_info_finish:
238 * @stream: a #GFileOutputStream.
239 * @result: a #GAsyncResult.
240 * @error: a #GError, %NULL to ignore.
242 * Finalizes the asynchronous query started
243 * by g_file_output_stream_query_info_async().
245 * Returns: (transfer full): A #GFileInfo for the finished query.
248 g_file_output_stream_query_info_finish (GFileOutputStream *stream,
249 GAsyncResult *result,
252 GFileOutputStreamClass *class;
254 g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), NULL);
255 g_return_val_if_fail (G_IS_ASYNC_RESULT (result), NULL);
257 if (g_async_result_legacy_propagate_error (result, error))
259 else if (g_async_result_is_tagged (result, g_file_output_stream_query_info_async))
260 return g_task_propagate_pointer (G_TASK (result), error);
262 class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
263 return class->query_info_finish (stream, result, error);
267 * g_file_output_stream_get_etag:
268 * @stream: a #GFileOutputStream.
270 * Gets the entity tag for the file when it has been written.
271 * This must be called after the stream has been written
272 * and closed, as the etag can change while writing.
274 * Returns: the entity tag for the stream.
277 g_file_output_stream_get_etag (GFileOutputStream *stream)
279 GFileOutputStreamClass *class;
280 GOutputStream *output_stream;
283 g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), NULL);
285 output_stream = G_OUTPUT_STREAM (stream);
287 if (!g_output_stream_is_closed (output_stream))
289 g_warning ("stream is not closed yet, can't get etag");
295 class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
297 etag = class->get_etag (stream);
303 g_file_output_stream_tell (GFileOutputStream *stream)
305 GFileOutputStreamClass *class;
308 g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), 0);
310 class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
314 offset = class->tell (stream);
320 g_file_output_stream_seekable_tell (GSeekable *seekable)
322 return g_file_output_stream_tell (G_FILE_OUTPUT_STREAM (seekable));
326 g_file_output_stream_can_seek (GFileOutputStream *stream)
328 GFileOutputStreamClass *class;
331 g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
333 class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
340 can_seek = class->can_seek (stream);
347 g_file_output_stream_seekable_can_seek (GSeekable *seekable)
349 return g_file_output_stream_can_seek (G_FILE_OUTPUT_STREAM (seekable));
353 g_file_output_stream_seek (GFileOutputStream *stream,
356 GCancellable *cancellable,
359 GFileOutputStreamClass *class;
360 GOutputStream *output_stream;
363 g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
365 output_stream = G_OUTPUT_STREAM (stream);
366 class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
370 g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
371 _("Seek not supported on stream"));
375 if (!g_output_stream_set_pending (output_stream, error))
379 g_cancellable_push_current (cancellable);
381 res = class->seek (stream, offset, type, cancellable, error);
384 g_cancellable_pop_current (cancellable);
386 g_output_stream_clear_pending (output_stream);
392 g_file_output_stream_seekable_seek (GSeekable *seekable,
395 GCancellable *cancellable,
398 return g_file_output_stream_seek (G_FILE_OUTPUT_STREAM (seekable),
399 offset, type, cancellable, error);
403 g_file_output_stream_can_truncate (GFileOutputStream *stream)
405 GFileOutputStreamClass *class;
406 gboolean can_truncate;
408 g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
410 class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
412 can_truncate = FALSE;
413 if (class->truncate_fn)
416 if (class->can_truncate)
417 can_truncate = class->can_truncate (stream);
424 g_file_output_stream_seekable_can_truncate (GSeekable *seekable)
426 return g_file_output_stream_can_truncate (G_FILE_OUTPUT_STREAM (seekable));
430 g_file_output_stream_truncate (GFileOutputStream *stream,
432 GCancellable *cancellable,
435 GFileOutputStreamClass *class;
436 GOutputStream *output_stream;
439 g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
441 output_stream = G_OUTPUT_STREAM (stream);
442 class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
444 if (!class->truncate_fn)
446 g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
447 _("Truncate not supported on stream"));
451 if (!g_output_stream_set_pending (output_stream, error))
455 g_cancellable_push_current (cancellable);
457 res = class->truncate_fn (stream, size, cancellable, error);
460 g_cancellable_pop_current (cancellable);
462 g_output_stream_clear_pending (output_stream);
468 g_file_output_stream_seekable_truncate (GSeekable *seekable,
470 GCancellable *cancellable,
473 return g_file_output_stream_truncate (G_FILE_OUTPUT_STREAM (seekable),
474 size, cancellable, error);
476 /********************************************
477 * Default implementation of async ops *
478 ********************************************/
481 query_info_async_thread (GTask *task,
482 gpointer source_object,
484 GCancellable *cancellable)
486 GFileOutputStream *stream = source_object;
487 const char *attributes = task_data;
488 GFileOutputStreamClass *class;
489 GError *error = NULL;
490 GFileInfo *info = NULL;
492 class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
493 if (class->query_info)
494 info = class->query_info (stream, attributes, cancellable, &error);
496 g_set_error_literal (&error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
497 _("Stream doesn't support query_info"));
500 g_task_return_error (task, error);
502 g_task_return_pointer (task, info, g_object_unref);
506 g_file_output_stream_real_query_info_async (GFileOutputStream *stream,
507 const char *attributes,
509 GCancellable *cancellable,
510 GAsyncReadyCallback callback,
515 task = g_task_new (stream, cancellable, callback, user_data);
516 g_task_set_task_data (task, g_strdup (attributes), g_free);
517 g_task_set_priority (task, io_priority);
519 g_task_run_in_thread (task, query_info_async_thread);
520 g_object_unref (task);
524 g_file_output_stream_real_query_info_finish (GFileOutputStream *stream,
528 g_return_val_if_fail (g_task_is_valid (res, stream), NULL);
530 return g_task_propagate_pointer (G_TASK (res), error);