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 "glibintl.h"
  30
  31 /**
  32  * SECTION:gfileoutputstream
  33  * @short_description: file output streaming operations
  34  * @see_also: #GOutputStream, #GDataOutputStream, #GSeekable
  35  *
  36  *
  37  *
  38  **/
  39
  40 static void       g_file_output_stream_seekable_iface_init    (GSeekableIface       *iface);
  41 static goffset    g_file_output_stream_seekable_tell          (GSeekable            *seekable);
  42 static gboolean   g_file_output_stream_seekable_can_seek      (GSeekable            *seekable);
  43 static gboolean   g_file_output_stream_seekable_seek          (GSeekable            *seekable,
  44                                                                goffset               offset,
  45                                                                GSeekType             type,
  46                                                                GCancellable         *cancellable,
  47                                                                GError              **error);
  48 static gboolean   g_file_output_stream_seekable_can_truncate  (GSeekable            *seekable);
  49 static gboolean   g_file_output_stream_seekable_truncate      (GSeekable            *seekable,
  50                                                                goffset               offset,
  51                                                                GCancellable         *cancellable,
  52                                                                GError              **error);
  53 static void       g_file_output_stream_real_query_info_async  (GFileOutputStream    *stream,
  54                                                                char                 *attributes,
  55                                                                int                   io_priority,
  56                                                                GCancellable         *cancellable,
  57                                                                GAsyncReadyCallback   callback,
  58                                                                gpointer              user_data);
  59 static GFileInfo *g_file_output_stream_real_query_info_finish (GFileOutputStream    *stream,
  60                                                                GAsyncResult         *result,
  61                                                                GError              **error);
  62
  63 G_DEFINE_TYPE_WITH_CODE (GFileOutputStream, g_file_output_stream, G_TYPE_OUTPUT_STREAM,
  64                          G_IMPLEMENT_INTERFACE (G_TYPE_SEEKABLE,
  65                                                 g_file_output_stream_seekable_iface_init));
  66
  67 struct _GFileOutputStreamPrivate {
  68   GAsyncReadyCallback outstanding_callback;
  69 };
  70
  71 static void
  72 g_file_output_stream_class_init (GFileOutputStreamClass *klass)
  73 {
  74   g_type_class_add_private (klass, sizeof (GFileOutputStreamPrivate));
  75
  76   klass->query_info_async = g_file_output_stream_real_query_info_async;
  77   klass->query_info_finish = g_file_output_stream_real_query_info_finish;
  78 }
  79
  80 static void
  81 g_file_output_stream_seekable_iface_init (GSeekableIface *iface)
  82 {
  83   iface->tell = g_file_output_stream_seekable_tell;
  84   iface->can_seek = g_file_output_stream_seekable_can_seek;
  85   iface->seek = g_file_output_stream_seekable_seek;
  86   iface->can_truncate = g_file_output_stream_seekable_can_truncate;
  87   iface->truncate = g_file_output_stream_seekable_truncate;
  88 }
  89
  90 static void
  91 g_file_output_stream_init (GFileOutputStream *stream)
  92 {
  93   stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (stream,
  94                                               G_TYPE_FILE_OUTPUT_STREAM,
  95                                               GFileOutputStreamPrivate);
  96 }
  97
  98 /**
  99  * g_file_output_stream_query_info:
 100  * @stream: a #GFileOutputStream.
 101  * @attributes: a file attribute query string.
 102  * @cancellable: optional #GCancellable object, %NULL to ignore.
 103  * @error: a #GError, %NULL to ignore.
 104  *
 105  * Queries a file output stream for the given @attributes.
 106  * This function blocks while querying the stream. For the asynchronous
 107  * version of this function, see g_file_output_stream_query_info_async().
 108  * While the stream is blocked, the stream will set the pending flag
 109  * internally, and any other operations on the stream will fail with
 110  * %G_IO_ERROR_PENDING.
 111  *
 112  * Can fail if the stream was already closed (with @error being set to
 113  * %G_IO_ERROR_CLOSED), the stream has pending operations (with @error being
 114  * set to %G_IO_ERROR_PENDING), or if querying info is not supported for
 115  * the stream's interface (with @error being set to %G_IO_ERROR_NOT_SUPPORTED). In
 116  * all cases of failure, %NULL will be returned.
 117  *
 118  * If @cancellable is not %NULL, then the operation can be cancelled by
 119  * triggering the cancellable object from another thread. If the operation
 120  * was cancelled, the error %G_IO_ERROR_CANCELLED will be set, and %NULL will
 121  * be returned.
 122  *
 123  * Returns: a #GFileInfo for the @stream, or %NULL on error.
 124  **/
 125 GFileInfo *
 126 g_file_output_stream_query_info (GFileOutputStream      *stream,
 127                                     char                   *attributes,
 128                                     GCancellable           *cancellable,
 129                                     GError                **error)
 130 {
 131   GFileOutputStreamClass *class;
 132   GOutputStream *output_stream;
 133   GFileInfo *info;
 134
 135   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), NULL);
 136
 137   output_stream = G_OUTPUT_STREAM (stream);
 138
 139   if (g_output_stream_is_closed (output_stream))
 140     {
 141       g_set_error (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
 142                    _("Stream is already closed"));
 143       return NULL;
 144     }
 145
 146   if (g_output_stream_has_pending (output_stream))
 147     {
 148       g_set_error (error, G_IO_ERROR, G_IO_ERROR_PENDING,
 149                    _("Stream has outstanding operation"));
 150       return NULL;
 151     }
 152
 153   info = NULL;
 154
 155   g_output_stream_set_pending (output_stream, TRUE);
 156
 157   if (cancellable)
 158     g_push_current_cancellable (cancellable);
 159
 160   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 161   if (class->query_info)
 162     info = class->query_info (stream, attributes, cancellable, error);
 163   else
 164     g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 165                  _("Stream doesn't support query_info"));
 166
 167   if (cancellable)
 168     g_pop_current_cancellable (cancellable);
 169
 170   g_output_stream_set_pending (output_stream, FALSE);
 171
 172   return info;
 173 }
 174
 175 static void
 176 async_ready_callback_wrapper (GObject *source_object,
 177                               GAsyncResult *res,
 178                               gpointer      user_data)
 179 {
 180   GFileOutputStream *stream = G_FILE_OUTPUT_STREAM (source_object);
 181
 182   g_output_stream_set_pending (G_OUTPUT_STREAM (stream), FALSE);
 183   if (stream->priv->outstanding_callback)
 184     (*stream->priv->outstanding_callback) (source_object, res, user_data);
 185   g_object_unref (stream);
 186 }
 187
 188 /**
 189  * g_file_output_stream_query_info_async:
 190  * @stream: a #GFileOutputStream.
 191  * @attributes: a file attribute query string.
 192  * @io_priority: the io priority of the request.
 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
 196  *
 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().
 200  *
 201  * For the synchronous version of this function, see
 202  * g_file_output_stream_query_info().
 203  *
 204  **/
 205 void
 206 g_file_output_stream_query_info_async (GFileOutputStream     *stream,
 207                                           char                 *attributes,
 208                                           int                   io_priority,
 209                                           GCancellable         *cancellable,
 210                                           GAsyncReadyCallback   callback,
 211                                           gpointer              user_data)
 212 {
 213   GFileOutputStreamClass *klass;
 214   GOutputStream *output_stream;
 215
 216   g_return_if_fail (G_IS_FILE_OUTPUT_STREAM (stream));
 217
 218   output_stream = G_OUTPUT_STREAM (stream);
 219
 220   if (g_output_stream_is_closed (output_stream))
 221     {
 222       g_simple_async_report_error_in_idle (G_OBJECT (stream),
 223                                            callback,
 224                                            user_data,
 225                                            G_IO_ERROR, G_IO_ERROR_CLOSED,
 226                                            _("Stream is already closed"));
 227       return;
 228     }
 229
 230   if (g_output_stream_has_pending (output_stream))
 231     {
 232       g_simple_async_report_error_in_idle (G_OBJECT (stream),
 233                                            callback,
 234                                            user_data,
 235                                            G_IO_ERROR, G_IO_ERROR_PENDING,
 236                                            _("Stream has outstanding operation"));
 237       return;
 238     }
 239
 240   klass = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 241
 242   g_output_stream_set_pending (output_stream, TRUE);
 243   stream->priv->outstanding_callback = callback;
 244   g_object_ref (stream);
 245   klass->query_info_async (stream, attributes, io_priority, cancellable,
 246                               async_ready_callback_wrapper, user_data);
 247 }
 248
 249 /**
 250  * g_file_output_stream_query_info_finish:
 251  * @stream: a #GFileOutputStream.
 252  * @result: a #GAsyncResult.
 253  * @error: a #GError, %NULL to ignore.
 254  *
 255  * Finalizes the asynchronous query started
 256  * by g_file_output_stream_query_info_async().
 257  *
 258  * Returns: A #GFileInfo for the finished query.
 259  **/
 260 GFileInfo *
 261 g_file_output_stream_query_info_finish (GFileOutputStream     *stream,
 262                                            GAsyncResult         *result,
 263                                            GError              **error)
 264 {
 265   GSimpleAsyncResult *simple;
 266   GFileOutputStreamClass *class;
 267
 268   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), NULL);
 269   g_return_val_if_fail (G_IS_ASYNC_RESULT (result), NULL);
 270
 271   if (G_IS_SIMPLE_ASYNC_RESULT (result))
 272     {
 273       simple = G_SIMPLE_ASYNC_RESULT (result);
 274       if (g_simple_async_result_propagate_error (simple, error))
 275         return NULL;
 276     }
 277
 278   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 279   return class->query_info_finish (stream, result, error);
 280 }
 281
 282 /**
 283  * g_file_output_stream_get_etag:
 284  * @stream: a #GFileOutputStream.
 285  *
 286  * Gets the entity tag for the file output stream.
 287  *
 288  * Returns: the entity tag for the stream.
 289  **/
 290 char *
 291 g_file_output_stream_get_etag (GFileOutputStream  *stream)
 292 {
 293   GFileOutputStreamClass *class;
 294   GOutputStream *output_stream;
 295   char *etag;
 296
 297   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), NULL);
 298
 299   output_stream = G_OUTPUT_STREAM (stream);
 300
 301   if (!g_output_stream_is_closed (output_stream))
 302     {
 303       g_warning ("stream is not closed yet, can't get etag");
 304       return NULL;
 305     }
 306
 307   etag = NULL;
 308
 309   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 310   if (class->get_etag)
 311     etag = class->get_etag (stream);
 312
 313   return etag;
 314 }
 315
 316 /**
 317  * g_file_output_stream_tell:
 318  * @stream: a #GFileOutputStream.
 319  *
 320  * Gets the current location within the stream.
 321  *
 322  * Returns: a #goffset of the location within the stream.
 323  **/
 324 goffset
 325 g_file_output_stream_tell (GFileOutputStream  *stream)
 326 {
 327   GFileOutputStreamClass *class;
 328   goffset offset;
 329
 330   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), 0);
 331
 332   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 333
 334   offset = 0;
 335   if (class->tell)
 336     offset = class->tell (stream);
 337
 338   return offset;
 339 }
 340
 341 static goffset
 342 g_file_output_stream_seekable_tell (GSeekable *seekable)
 343 {
 344   return g_file_output_stream_tell (G_FILE_OUTPUT_STREAM (seekable));
 345 }
 346
 347 /**
 348  * g_file_output_stream_can_seek:
 349  * @stream: a #GFileOutputStream.
 350  *
 351  * Checks if the stream can be seeked.
 352  *
 353  * Returns: %TRUE if seeking is supported by the stream.
 354  **/
 355 gboolean
 356 g_file_output_stream_can_seek (GFileOutputStream  *stream)
 357 {
 358   GFileOutputStreamClass *class;
 359   gboolean can_seek;
 360
 361   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
 362
 363   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 364
 365   can_seek = FALSE;
 366   if (class->seek)
 367     {
 368       can_seek = TRUE;
 369       if (class->can_seek)
 370         can_seek = class->can_seek (stream);
 371     }
 372
 373   return can_seek;
 374 }
 375
 376 static gboolean
 377 g_file_output_stream_seekable_can_seek (GSeekable *seekable)
 378 {
 379   return g_file_output_stream_can_seek (G_FILE_OUTPUT_STREAM (seekable));
 380 }
 381
 382 /**
 383  * g_file_output_stream_seek:
 384  * @stream: a #GFileOutputStream.
 385  * @offset: a #goffset to seek.
 386  * @type: a #GSeekType.
 387  * @cancellable: optional #GCancellable object, %NULL to ignore.
 388  * @error: a #GError, %NULL to ignore.
 389  *
 390  * Seeks to a location in a file output stream.
 391  *
 392  * Returns: %TRUE if the seek was successful. %FALSE otherwise.
 393  **/
 394 gboolean
 395 g_file_output_stream_seek (GFileOutputStream  *stream,
 396                            goffset             offset,
 397                            GSeekType           type,
 398                            GCancellable       *cancellable,
 399                            GError            **error)
 400 {
 401   GFileOutputStreamClass *class;
 402   GOutputStream *output_stream;
 403   gboolean res;
 404
 405   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
 406
 407   output_stream = G_OUTPUT_STREAM (stream);
 408   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 409
 410   if (g_output_stream_is_closed (output_stream))
 411     {
 412       g_set_error (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
 413                    _("Stream is already closed"));
 414       return FALSE;
 415     }
 416
 417   if (g_output_stream_has_pending (output_stream))
 418     {
 419       g_set_error (error, G_IO_ERROR, G_IO_ERROR_PENDING,
 420                    _("Stream has outstanding operation"));
 421       return FALSE;
 422     }
 423
 424   if (!class->seek)
 425     {
 426       g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 427                    _("Seek not supported on stream"));
 428       return FALSE;
 429     }
 430
 431   g_output_stream_set_pending (output_stream, TRUE);
 432
 433   if (cancellable)
 434     g_push_current_cancellable (cancellable);
 435
 436   res = class->seek (stream, offset, type, cancellable, error);
 437
 438   if (cancellable)
 439     g_pop_current_cancellable (cancellable);
 440
 441   g_output_stream_set_pending (output_stream, FALSE);
 442
 443   return res;
 444 }
 445
 446 static gboolean
 447 g_file_output_stream_seekable_seek (GSeekable  *seekable,
 448                                     goffset     offset,
 449                                     GSeekType   type,
 450                                     GCancellable  *cancellable,
 451                                     GError    **error)
 452 {
 453   return g_file_output_stream_seek (G_FILE_OUTPUT_STREAM (seekable),
 454                                     offset, type, cancellable, error);
 455 }
 456
 457 /**
 458  * g_file_output_stream_can_truncate:
 459  * @stream: a #GFileOutputStream.
 460  *
 461  * Checks if the stream can be truncated.
 462  *
 463  * Returns: %TRUE if stream can be truncated.
 464  **/
 465 gboolean
 466 g_file_output_stream_can_truncate (GFileOutputStream  *stream)
 467 {
 468   GFileOutputStreamClass *class;
 469   gboolean can_truncate;
 470
 471   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
 472
 473   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 474
 475   can_truncate = FALSE;
 476   if (class->truncate)
 477     {
 478       can_truncate = TRUE;
 479       if (class->can_truncate)
 480         can_truncate = class->can_truncate (stream);
 481     }
 482
 483   return can_truncate;
 484 }
 485
 486 static gboolean
 487 g_file_output_stream_seekable_can_truncate (GSeekable  *seekable)
 488 {
 489   return g_file_output_stream_can_truncate (G_FILE_OUTPUT_STREAM (seekable));
 490 }
 491
 492 /**
 493  * g_file_output_stream_truncate:
 494  * @stream: a #GFileOutputStream.
 495  * @size: a #goffset to truncate the stream at.
 496  * @cancellable: optional #GCancellable object, %NULL to ignore.
 497  * @error: a #GError, %NULL to ignore.
 498  *
 499  * Truncates a file output stream.
 500  *
 501  * Returns: %TRUE if @stream is truncated successfully.
 502  **/
 503 gboolean
 504 g_file_output_stream_truncate (GFileOutputStream  *stream,
 505                                goffset             size,
 506                                GCancellable       *cancellable,
 507                                GError            **error)
 508 {
 509   GFileOutputStreamClass *class;
 510   GOutputStream *output_stream;
 511   gboolean res;
 512
 513   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
 514
 515   output_stream = G_OUTPUT_STREAM (stream);
 516   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 517
 518   if (g_output_stream_is_closed (output_stream))
 519     {
 520       g_set_error (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
 521                    _("Stream is already closed"));
 522       return FALSE;
 523     }
 524
 525   if (g_output_stream_has_pending (output_stream))
 526     {
 527       g_set_error (error, G_IO_ERROR, G_IO_ERROR_PENDING,
 528                    _("Stream has outstanding operation"));
 529       return FALSE;
 530     }
 531
 532   if (!class->truncate)
 533     {
 534       g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 535                    _("Truncate not supported on stream"));
 536       return FALSE;
 537     }
 538
 539   g_output_stream_set_pending (output_stream, TRUE);
 540
 541   if (cancellable)
 542     g_push_current_cancellable (cancellable);
 543
 544   res = class->truncate (stream, size, cancellable, error);
 545
 546   if (cancellable)
 547     g_pop_current_cancellable (cancellable);
 548
 549   g_output_stream_set_pending (output_stream, FALSE);
 550
 551   return res;
 552 }
 553
 554 static gboolean
 555 g_file_output_stream_seekable_truncate (GSeekable     *seekable,
 556                                         goffset        size,
 557                                         GCancellable  *cancellable,
 558                                         GError       **error)
 559 {
 560   return g_file_output_stream_truncate (G_FILE_OUTPUT_STREAM (seekable),
 561                                         size, cancellable, error);
 562 }
 563 /********************************************
 564  *   Default implementation of async ops    *
 565  ********************************************/
 566
 567 typedef struct {
 568   char *attributes;
 569   GFileInfo *info;
 570 } QueryInfoAsyncData;
 571
 572 static void
 573 query_info_data_free (QueryInfoAsyncData *data)
 574 {
 575   if (data->info)
 576     g_object_unref (data->info);
 577   g_free (data->attributes);
 578   g_free (data);
 579 }
 580
 581 static void
 582 query_info_async_thread (GSimpleAsyncResult *res,
 583                        GObject *object,
 584                        GCancellable *cancellable)
 585 {
 586   GFileOutputStreamClass *class;
 587   GError *error = NULL;
 588   QueryInfoAsyncData *data;
 589   GFileInfo *info;
 590
 591   data = g_simple_async_result_get_op_res_gpointer (res);
 592
 593   info = NULL;
 594
 595   class = G_FILE_OUTPUT_STREAM_GET_CLASS (object);
 596   if (class->query_info)
 597     info = class->query_info (G_FILE_OUTPUT_STREAM (object), data->attributes, cancellable, &error);
 598   else
 599     g_set_error (&error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 600                  _("Stream doesn't support query_info"));
 601
 602   if (info == NULL)
 603     {
 604       g_simple_async_result_set_from_error (res, error);
 605       g_error_free (error);
 606     }
 607   else
 608     data->info = info;
 609 }
 610
 611 static void
 612 g_file_output_stream_real_query_info_async (GFileOutputStream     *stream,
 613                                                char                 *attributes,
 614                                                int                   io_priority,
 615                                                GCancellable         *cancellable,
 616                                                GAsyncReadyCallback   callback,
 617                                                gpointer              user_data)
 618 {
 619   GSimpleAsyncResult *res;
 620   QueryInfoAsyncData *data;
 621
 622   data = g_new0 (QueryInfoAsyncData, 1);
 623   data->attributes = g_strdup (attributes);
 624
 625   res = g_simple_async_result_new (G_OBJECT (stream), callback, user_data, g_file_output_stream_real_query_info_async);
 626   g_simple_async_result_set_op_res_gpointer (res, data, (GDestroyNotify)query_info_data_free);
 627
 628   g_simple_async_result_run_in_thread (res, query_info_async_thread, io_priority, cancellable);
 629   g_object_unref (res);
 630 }
 631
 632 static GFileInfo *
 633 g_file_output_stream_real_query_info_finish (GFileOutputStream     *stream,
 634                                                 GAsyncResult         *res,
 635                                                 GError              **error)
 636 {
 637   GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (res);
 638   QueryInfoAsyncData *data;
 639
 640   g_assert (g_simple_async_result_get_source_tag (simple) == g_file_output_stream_real_query_info_async);
 641
 642   data = g_simple_async_result_get_op_res_gpointer (simple);
 643   if (data->info)
 644     return g_object_ref (data->info);
 645
 646   return NULL;
 647 }