Moved all relevant typedefs into these files.
[platform/upstream/glib.git] / gio / gfileoutputstream.c
1 /* GIO - GLib Input, Output 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 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, write to the
17  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
18  * Boston, MA 02111-1307, USA.
19  *
20  * Author: Alexander Larsson <alexl@redhat.com>
21  */
22
23 #include "config.h"
24
25 #include <glib.h>
26 #include <gfileoutputstream.h>
27 #include <gseekable.h>
28 #include "gsimpleasyncresult.h"
29 #include "gasyncresult.h"
30 #include "gcancellable.h"
31 #include "gioerror.h"
32 #include "glibintl.h"
33
34 #include "gioalias.h"
35
36 /**
37  * SECTION:gfileoutputstream
38  * @short_description: File output streaming operations
39  * @include: gio/gio.h
40  * @see_also: #GOutputStream, #GDataOutputStream, #GSeekable
41  * 
42  * GFileOutputStream provides output streams that write their
43  * content to a file.
44  *
45  * GFileOutputStream implements #GSeekable, which allows the output 
46  * stream to jump to arbitrary positions in the file and to truncate
47  * the file, provided the filesystem of the file supports these 
48  * operations. In addition to the generic g_seekable_ API, 
49  * GFileOutputStream has its own API for seeking and positioning. 
50  * To find the position of a file output stream, use 
51  * g_file_output_stream_tell(). To find out if a file output 
52  * stream supports seeking, use g_file_output_stream_can_seek().
53  * To position a file output stream, use g_file_output_stream_seek().
54  * To find out if a file output stream supports truncating, use
55  * g_file_output_stream_can_truncate(). To truncate a file output
56  * stream, use g_file_output_stream_truncate().
57  **/
58
59 static void       g_file_output_stream_seekable_iface_init    (GSeekableIface       *iface);
60 static goffset    g_file_output_stream_seekable_tell          (GSeekable            *seekable);
61 static gboolean   g_file_output_stream_seekable_can_seek      (GSeekable            *seekable);
62 static gboolean   g_file_output_stream_seekable_seek          (GSeekable            *seekable,
63                                                                goffset               offset,
64                                                                GSeekType             type,
65                                                                GCancellable         *cancellable,
66                                                                GError              **error);
67 static gboolean   g_file_output_stream_seekable_can_truncate  (GSeekable            *seekable);
68 static gboolean   g_file_output_stream_seekable_truncate      (GSeekable            *seekable,
69                                                                goffset               offset,
70                                                                GCancellable         *cancellable,
71                                                                GError              **error);
72 static void       g_file_output_stream_real_query_info_async  (GFileOutputStream    *stream,
73                                                                char                 *attributes,
74                                                                int                   io_priority,
75                                                                GCancellable         *cancellable,
76                                                                GAsyncReadyCallback   callback,
77                                                                gpointer              user_data);
78 static GFileInfo *g_file_output_stream_real_query_info_finish (GFileOutputStream    *stream,
79                                                                GAsyncResult         *result,
80                                                                GError              **error);
81
82 G_DEFINE_TYPE_WITH_CODE (GFileOutputStream, g_file_output_stream, G_TYPE_OUTPUT_STREAM,
83                          G_IMPLEMENT_INTERFACE (G_TYPE_SEEKABLE,
84                                                 g_file_output_stream_seekable_iface_init));
85
86 struct _GFileOutputStreamPrivate {
87   GAsyncReadyCallback outstanding_callback;
88 };
89
90 static void
91 g_file_output_stream_class_init (GFileOutputStreamClass *klass)
92 {
93   g_type_class_add_private (klass, sizeof (GFileOutputStreamPrivate));
94
95   klass->query_info_async = g_file_output_stream_real_query_info_async;
96   klass->query_info_finish = g_file_output_stream_real_query_info_finish;
97 }
98
99 static void
100 g_file_output_stream_seekable_iface_init (GSeekableIface *iface)
101 {
102   iface->tell = g_file_output_stream_seekable_tell;
103   iface->can_seek = g_file_output_stream_seekable_can_seek;
104   iface->seek = g_file_output_stream_seekable_seek;
105   iface->can_truncate = g_file_output_stream_seekable_can_truncate;
106   iface->truncate_fn = g_file_output_stream_seekable_truncate;
107 }
108
109 static void
110 g_file_output_stream_init (GFileOutputStream *stream)
111 {
112   stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (stream,
113                                               G_TYPE_FILE_OUTPUT_STREAM,
114                                               GFileOutputStreamPrivate);
115 }
116
117 /**
118  * g_file_output_stream_query_info:
119  * @stream: a #GFileOutputStream.
120  * @attributes: a file attribute query string.
121  * @cancellable: optional #GCancellable object, %NULL to ignore. 
122  * @error: a #GError, %NULL to ignore.
123  *
124  * Queries a file output stream for the given @attributes. 
125  * This function blocks while querying the stream. For the asynchronous 
126  * version of this function, see g_file_output_stream_query_info_async(). 
127  * While the stream is blocked, the stream will set the pending flag 
128  * internally, and any other operations on the stream will fail with 
129  * %G_IO_ERROR_PENDING.
130  * 
131  * Can fail if the stream was already closed (with @error being set to 
132  * %G_IO_ERROR_CLOSED), the stream has pending operations (with @error being
133  * set to %G_IO_ERROR_PENDING), or if querying info is not supported for 
134  * the stream's interface (with @error being set to %G_IO_ERROR_NOT_SUPPORTED). In
135  * all cases of failure, %NULL will be returned.
136  * 
137  * If @cancellable is not %NULL, then the operation can be cancelled by
138  * triggering the cancellable object from another thread. If the operation
139  * was cancelled, the error %G_IO_ERROR_CANCELLED will be set, and %NULL will 
140  * be returned. 
141  * 
142  * Returns: a #GFileInfo for the @stream, or %NULL on error.
143  **/
144 GFileInfo *
145 g_file_output_stream_query_info (GFileOutputStream      *stream,
146                                     char                   *attributes,
147                                     GCancellable           *cancellable,
148                                     GError                **error)
149 {
150   GFileOutputStreamClass *class;
151   GOutputStream *output_stream;
152   GFileInfo *info;
153   
154   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), NULL);
155   
156   output_stream = G_OUTPUT_STREAM (stream);
157   
158   if (!g_output_stream_set_pending (output_stream, error))
159     return NULL;
160       
161   info = NULL;
162   
163   if (cancellable)
164     g_cancellable_push_current (cancellable);
165   
166   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
167   if (class->query_info)
168     info = class->query_info (stream, attributes, cancellable, error);
169   else
170     g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
171                          _("Stream doesn't support query_info"));
172   
173   if (cancellable)
174     g_cancellable_pop_current (cancellable);
175   
176   g_output_stream_clear_pending (output_stream);
177   
178   return info;
179 }
180
181 static void
182 async_ready_callback_wrapper (GObject *source_object,
183                               GAsyncResult *res,
184                               gpointer      user_data)
185 {
186   GFileOutputStream *stream = G_FILE_OUTPUT_STREAM (source_object);
187
188   g_output_stream_clear_pending (G_OUTPUT_STREAM (stream));
189   if (stream->priv->outstanding_callback)
190     (*stream->priv->outstanding_callback) (source_object, res, user_data);
191   g_object_unref (stream);
192 }
193
194 /**
195  * g_file_output_stream_query_info_async:
196  * @stream: a #GFileOutputStream.
197  * @attributes: a file attribute query string.
198  * @io_priority: the <link linkend="gio-GIOScheduler">I/O priority</link> 
199  *     of the request.
200  * @cancellable: optional #GCancellable object, %NULL to ignore. 
201  * @callback: callback to call when the request is satisfied
202  * @user_data: the data to pass to callback function
203  * 
204  * Asynchronously queries the @stream for a #GFileInfo. When completed,
205  * @callback will be called with a #GAsyncResult which can be used to 
206  * finish the operation with g_file_output_stream_query_info_finish().
207  * 
208  * For the synchronous version of this function, see 
209  * g_file_output_stream_query_info().
210  *
211  **/
212 void
213 g_file_output_stream_query_info_async (GFileOutputStream     *stream,
214                                           char                 *attributes,
215                                           int                   io_priority,
216                                           GCancellable         *cancellable,
217                                           GAsyncReadyCallback   callback,
218                                           gpointer              user_data)
219 {
220   GFileOutputStreamClass *klass;
221   GOutputStream *output_stream;
222   GError *error = NULL;
223
224   g_return_if_fail (G_IS_FILE_OUTPUT_STREAM (stream));
225
226   output_stream = G_OUTPUT_STREAM (stream);
227  
228   if (!g_output_stream_set_pending (output_stream, &error))
229     {
230       g_simple_async_report_gerror_in_idle (G_OBJECT (stream),
231                                             callback,
232                                             user_data,
233                                             error);
234       g_error_free (error);
235       return;
236     }
237
238   klass = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
239
240   stream->priv->outstanding_callback = callback;
241   g_object_ref (stream);
242   klass->query_info_async (stream, attributes, io_priority, cancellable,
243                               async_ready_callback_wrapper, user_data);
244 }
245
246 /**
247  * g_file_output_stream_query_info_finish:
248  * @stream: a #GFileOutputStream.
249  * @result: a #GAsyncResult.
250  * @error: a #GError, %NULL to ignore.
251  * 
252  * Finalizes the asynchronous query started 
253  * by g_file_output_stream_query_info_async().
254  * 
255  * Returns: A #GFileInfo for the finished query.
256  **/
257 GFileInfo *
258 g_file_output_stream_query_info_finish (GFileOutputStream     *stream,
259                                            GAsyncResult         *result,
260                                            GError              **error)
261 {
262   GSimpleAsyncResult *simple;
263   GFileOutputStreamClass *class;
264
265   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), NULL);
266   g_return_val_if_fail (G_IS_ASYNC_RESULT (result), NULL);
267   
268   if (G_IS_SIMPLE_ASYNC_RESULT (result))
269     {
270       simple = G_SIMPLE_ASYNC_RESULT (result);
271       if (g_simple_async_result_propagate_error (simple, error))
272         return NULL;
273     }
274
275   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
276   return class->query_info_finish (stream, result, error);
277 }
278
279 /**
280  * g_file_output_stream_get_etag:
281  * @stream: a #GFileOutputStream.
282  * 
283  * Gets the entity tag for the file when it has been written.
284  * This must be called after the stream has been written
285  * and closed, as the etag can change while writing.
286  * 
287  * Returns: the entity tag for the stream.
288  **/
289 char *
290 g_file_output_stream_get_etag (GFileOutputStream  *stream)
291 {
292   GFileOutputStreamClass *class;
293   GOutputStream *output_stream;
294   char *etag;
295   
296   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), NULL);
297   
298   output_stream = G_OUTPUT_STREAM (stream);
299   
300   if (!g_output_stream_is_closed (output_stream))
301     {
302       g_warning ("stream is not closed yet, can't get etag");
303       return NULL;
304     }
305
306   etag = NULL;
307   
308   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
309   if (class->get_etag)
310     etag = class->get_etag (stream);
311   
312   return etag;
313 }
314
315 static goffset
316 g_file_output_stream_tell (GFileOutputStream  *stream)
317 {
318   GFileOutputStreamClass *class;
319   goffset offset;
320   
321   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), 0);  
322
323   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
324
325   offset = 0;
326   if (class->tell)
327     offset = class->tell (stream);
328
329   return offset;
330 }
331
332 static goffset
333 g_file_output_stream_seekable_tell (GSeekable *seekable)
334 {
335   return g_file_output_stream_tell (G_FILE_OUTPUT_STREAM (seekable));
336 }
337
338 static gboolean
339 g_file_output_stream_can_seek (GFileOutputStream  *stream)
340 {
341   GFileOutputStreamClass *class;
342   gboolean can_seek;
343
344   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
345
346   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
347
348   can_seek = FALSE;
349   if (class->seek)
350     {
351       can_seek = TRUE;
352       if (class->can_seek)
353         can_seek = class->can_seek (stream);
354     }
355   
356   return can_seek;
357 }
358
359 static gboolean
360 g_file_output_stream_seekable_can_seek (GSeekable *seekable)
361 {
362   return g_file_output_stream_can_seek (G_FILE_OUTPUT_STREAM (seekable));
363 }
364
365 static gboolean
366 g_file_output_stream_seek (GFileOutputStream  *stream,
367                            goffset             offset,
368                            GSeekType           type,
369                            GCancellable       *cancellable,
370                            GError            **error)
371 {
372   GFileOutputStreamClass *class;
373   GOutputStream *output_stream;
374   gboolean res;
375
376   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
377
378   output_stream = G_OUTPUT_STREAM (stream);
379   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
380
381   if (!class->seek)
382     {
383       g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
384                            _("Seek not supported on stream"));
385       return FALSE;
386     }
387
388   if (!g_output_stream_set_pending (output_stream, error))
389     return FALSE;
390   
391   if (cancellable)
392     g_cancellable_push_current (cancellable);
393   
394   res = class->seek (stream, offset, type, cancellable, error);
395   
396   if (cancellable)
397     g_cancellable_pop_current (cancellable);
398
399   g_output_stream_clear_pending (output_stream);
400   
401   return res;
402 }
403
404 static gboolean
405 g_file_output_stream_seekable_seek (GSeekable  *seekable,
406                                     goffset     offset,
407                                     GSeekType   type,
408                                     GCancellable  *cancellable,
409                                     GError    **error)
410 {
411   return g_file_output_stream_seek (G_FILE_OUTPUT_STREAM (seekable),
412                                     offset, type, cancellable, error);
413 }
414
415 static gboolean
416 g_file_output_stream_can_truncate (GFileOutputStream  *stream)
417 {
418   GFileOutputStreamClass *class;
419   gboolean can_truncate;
420
421   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
422
423   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
424
425   can_truncate = FALSE;
426   if (class->truncate_fn)
427     {
428       can_truncate = TRUE;
429       if (class->can_truncate)
430         can_truncate = class->can_truncate (stream);
431     }
432   
433   return can_truncate;
434 }
435
436 static gboolean
437 g_file_output_stream_seekable_can_truncate (GSeekable  *seekable)
438 {
439   return g_file_output_stream_can_truncate (G_FILE_OUTPUT_STREAM (seekable));
440 }
441
442 static gboolean
443 g_file_output_stream_truncate (GFileOutputStream  *stream,
444                                goffset             size,
445                                GCancellable       *cancellable,
446                                GError            **error)
447 {
448   GFileOutputStreamClass *class;
449   GOutputStream *output_stream;
450   gboolean res;
451
452   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
453
454   output_stream = G_OUTPUT_STREAM (stream);
455   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
456
457   if (!class->truncate_fn)
458     {
459       g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
460                            _("Truncate not supported on stream"));
461       return FALSE;
462     }
463
464   if (!g_output_stream_set_pending (output_stream, error))
465     return FALSE;
466   
467   if (cancellable)
468     g_cancellable_push_current (cancellable);
469   
470   res = class->truncate_fn (stream, size, cancellable, error);
471   
472   if (cancellable)
473     g_cancellable_pop_current (cancellable);
474
475   g_output_stream_clear_pending (output_stream);
476   
477   return res;
478 }
479
480 static gboolean
481 g_file_output_stream_seekable_truncate (GSeekable     *seekable,
482                                         goffset        size,
483                                         GCancellable  *cancellable,
484                                         GError       **error)
485 {
486   return g_file_output_stream_truncate (G_FILE_OUTPUT_STREAM (seekable),
487                                         size, cancellable, error);
488 }
489 /********************************************
490  *   Default implementation of async ops    *
491  ********************************************/
492
493 typedef struct {
494   char *attributes;
495   GFileInfo *info;
496 } QueryInfoAsyncData;
497
498 static void
499 query_info_data_free (QueryInfoAsyncData *data)
500 {
501   if (data->info)
502     g_object_unref (data->info);
503   g_free (data->attributes);
504   g_free (data);
505 }
506
507 static void
508 query_info_async_thread (GSimpleAsyncResult *res,
509                        GObject *object,
510                        GCancellable *cancellable)
511 {
512   GFileOutputStreamClass *class;
513   GError *error = NULL;
514   QueryInfoAsyncData *data;
515   GFileInfo *info;
516   
517   data = g_simple_async_result_get_op_res_gpointer (res);
518
519   info = NULL;
520   
521   class = G_FILE_OUTPUT_STREAM_GET_CLASS (object);
522   if (class->query_info)
523     info = class->query_info (G_FILE_OUTPUT_STREAM (object), data->attributes, cancellable, &error);
524   else
525     g_set_error_literal (&error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
526                          _("Stream doesn't support query_info"));
527
528   if (info == NULL)
529     {
530       g_simple_async_result_set_from_error (res, error);
531       g_error_free (error);
532     }
533   else
534     data->info = info;
535 }
536
537 static void
538 g_file_output_stream_real_query_info_async (GFileOutputStream     *stream,
539                                                char                 *attributes,
540                                                int                   io_priority,
541                                                GCancellable         *cancellable,
542                                                GAsyncReadyCallback   callback,
543                                                gpointer              user_data)
544 {
545   GSimpleAsyncResult *res;
546   QueryInfoAsyncData *data;
547
548   data = g_new0 (QueryInfoAsyncData, 1);
549   data->attributes = g_strdup (attributes);
550   
551   res = g_simple_async_result_new (G_OBJECT (stream), callback, user_data, g_file_output_stream_real_query_info_async);
552   g_simple_async_result_set_op_res_gpointer (res, data, (GDestroyNotify)query_info_data_free);
553   
554   g_simple_async_result_run_in_thread (res, query_info_async_thread, io_priority, cancellable);
555   g_object_unref (res);
556 }
557
558 static GFileInfo *
559 g_file_output_stream_real_query_info_finish (GFileOutputStream     *stream,
560                                                 GAsyncResult         *res,
561                                                 GError              **error)
562 {
563   GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (res);
564   QueryInfoAsyncData *data;
565
566   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_file_output_stream_real_query_info_async);
567
568   data = g_simple_async_result_get_op_res_gpointer (simple);
569   if (data->info)
570     return g_object_ref (data->info);
571   
572   return NULL;
573 }
574
575 #define __G_FILE_OUTPUT_STREAM_C__
576 #include "gioaliasdef.c"