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 #include "gioalias.h"
  32
  33 /**
  34  * SECTION:gfileoutputstream
  35  * @short_description: file output streaming operations
  36  * @see_also: #GOutputStream, #GDataOutputStream, #GSeekable
  37  *
  38  *
  39  *
  40  **/
  41
  42 static void       g_file_output_stream_seekable_iface_init    (GSeekableIface       *iface);
  43 static goffset    g_file_output_stream_seekable_tell          (GSeekable            *seekable);
  44 static gboolean   g_file_output_stream_seekable_can_seek      (GSeekable            *seekable);
  45 static gboolean   g_file_output_stream_seekable_seek          (GSeekable            *seekable,
  46                                                                goffset               offset,
  47                                                                GSeekType             type,
  48                                                                GCancellable         *cancellable,
  49                                                                GError              **error);
  50 static gboolean   g_file_output_stream_seekable_can_truncate  (GSeekable            *seekable);
  51 static gboolean   g_file_output_stream_seekable_truncate      (GSeekable            *seekable,
  52                                                                goffset               offset,
  53                                                                GCancellable         *cancellable,
  54                                                                GError              **error);
  55 static void       g_file_output_stream_real_query_info_async  (GFileOutputStream    *stream,
  56                                                                char                 *attributes,
  57                                                                int                   io_priority,
  58                                                                GCancellable         *cancellable,
  59                                                                GAsyncReadyCallback   callback,
  60                                                                gpointer              user_data);
  61 static GFileInfo *g_file_output_stream_real_query_info_finish (GFileOutputStream    *stream,
  62                                                                GAsyncResult         *result,
  63                                                                GError              **error);
  64
  65 G_DEFINE_TYPE_WITH_CODE (GFileOutputStream, g_file_output_stream, G_TYPE_OUTPUT_STREAM,
  66                          G_IMPLEMENT_INTERFACE (G_TYPE_SEEKABLE,
  67                                                 g_file_output_stream_seekable_iface_init));
  68
  69 struct _GFileOutputStreamPrivate {
  70   GAsyncReadyCallback outstanding_callback;
  71 };
  72
  73 static void
  74 g_file_output_stream_class_init (GFileOutputStreamClass *klass)
  75 {
  76   g_type_class_add_private (klass, sizeof (GFileOutputStreamPrivate));
  77
  78   klass->query_info_async = g_file_output_stream_real_query_info_async;
  79   klass->query_info_finish = g_file_output_stream_real_query_info_finish;
  80 }
  81
  82 static void
  83 g_file_output_stream_seekable_iface_init (GSeekableIface *iface)
  84 {
  85   iface->tell = g_file_output_stream_seekable_tell;
  86   iface->can_seek = g_file_output_stream_seekable_can_seek;
  87   iface->seek = g_file_output_stream_seekable_seek;
  88   iface->can_truncate = g_file_output_stream_seekable_can_truncate;
  89   iface->truncate = g_file_output_stream_seekable_truncate;
  90 }
  91
  92 static void
  93 g_file_output_stream_init (GFileOutputStream *stream)
  94 {
  95   stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (stream,
  96                                               G_TYPE_FILE_OUTPUT_STREAM,
  97                                               GFileOutputStreamPrivate);
  98 }
  99
 100 /**
 101  * g_file_output_stream_query_info:
 102  * @stream: a #GFileOutputStream.
 103  * @attributes: a file attribute query string.
 104  * @cancellable: optional #GCancellable object, %NULL to ignore.
 105  * @error: a #GError, %NULL to ignore.
 106  *
 107  * Queries a file output stream for the given @attributes.
 108  * This function blocks while querying the stream. For the asynchronous
 109  * version of this function, see g_file_output_stream_query_info_async().
 110  * While the stream is blocked, the stream will set the pending flag
 111  * internally, and any other operations on the stream will fail with
 112  * %G_IO_ERROR_PENDING.
 113  *
 114  * Can fail if the stream was already closed (with @error being set to
 115  * %G_IO_ERROR_CLOSED), the stream has pending operations (with @error being
 116  * set to %G_IO_ERROR_PENDING), or if querying info is not supported for
 117  * the stream's interface (with @error being set to %G_IO_ERROR_NOT_SUPPORTED). In
 118  * all cases of failure, %NULL will be returned.
 119  *
 120  * If @cancellable is not %NULL, then the operation can be cancelled by
 121  * triggering the cancellable object from another thread. If the operation
 122  * was cancelled, the error %G_IO_ERROR_CANCELLED will be set, and %NULL will
 123  * be returned.
 124  *
 125  * Returns: a #GFileInfo for the @stream, or %NULL on error.
 126  **/
 127 GFileInfo *
 128 g_file_output_stream_query_info (GFileOutputStream      *stream,
 129                                     char                   *attributes,
 130                                     GCancellable           *cancellable,
 131                                     GError                **error)
 132 {
 133   GFileOutputStreamClass *class;
 134   GOutputStream *output_stream;
 135   GFileInfo *info;
 136
 137   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), NULL);
 138
 139   output_stream = G_OUTPUT_STREAM (stream);
 140
 141   if (g_output_stream_is_closed (output_stream))
 142     {
 143       g_set_error (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
 144                    _("Stream is already closed"));
 145       return NULL;
 146     }
 147
 148   if (g_output_stream_has_pending (output_stream))
 149     {
 150       g_set_error (error, G_IO_ERROR, G_IO_ERROR_PENDING,
 151                    _("Stream has outstanding operation"));
 152       return NULL;
 153     }
 154
 155   info = NULL;
 156
 157   g_output_stream_set_pending (output_stream, TRUE);
 158
 159   if (cancellable)
 160     g_push_current_cancellable (cancellable);
 161
 162   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 163   if (class->query_info)
 164     info = class->query_info (stream, attributes, cancellable, error);
 165   else
 166     g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 167                  _("Stream doesn't support query_info"));
 168
 169   if (cancellable)
 170     g_pop_current_cancellable (cancellable);
 171
 172   g_output_stream_set_pending (output_stream, FALSE);
 173
 174   return info;
 175 }
 176
 177 static void
 178 async_ready_callback_wrapper (GObject *source_object,
 179                               GAsyncResult *res,
 180                               gpointer      user_data)
 181 {
 182   GFileOutputStream *stream = G_FILE_OUTPUT_STREAM (source_object);
 183
 184   g_output_stream_set_pending (G_OUTPUT_STREAM (stream), FALSE);
 185   if (stream->priv->outstanding_callback)
 186     (*stream->priv->outstanding_callback) (source_object, res, user_data);
 187   g_object_unref (stream);
 188 }
 189
 190 /**
 191  * g_file_output_stream_query_info_async:
 192  * @stream: a #GFileOutputStream.
 193  * @attributes: a file attribute query string.
 194  * @io_priority: the io priority of the request.
 195  * @cancellable: optional #GCancellable object, %NULL to ignore.
 196  * @callback: callback to call when the request is satisfied
 197  * @user_data: 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_output_stream_query_info_finish().
 202  *
 203  * For the synchronous version of this function, see
 204  * g_file_output_stream_query_info().
 205  *
 206  **/
 207 void
 208 g_file_output_stream_query_info_async (GFileOutputStream     *stream,
 209                                           char                 *attributes,
 210                                           int                   io_priority,
 211                                           GCancellable         *cancellable,
 212                                           GAsyncReadyCallback   callback,
 213                                           gpointer              user_data)
 214 {
 215   GFileOutputStreamClass *klass;
 216   GOutputStream *output_stream;
 217
 218   g_return_if_fail (G_IS_FILE_OUTPUT_STREAM (stream));
 219
 220   output_stream = G_OUTPUT_STREAM (stream);
 221
 222   if (g_output_stream_is_closed (output_stream))
 223     {
 224       g_simple_async_report_error_in_idle (G_OBJECT (stream),
 225                                            callback,
 226                                            user_data,
 227                                            G_IO_ERROR, G_IO_ERROR_CLOSED,
 228                                            _("Stream is already closed"));
 229       return;
 230     }
 231
 232   if (g_output_stream_has_pending (output_stream))
 233     {
 234       g_simple_async_report_error_in_idle (G_OBJECT (stream),
 235                                            callback,
 236                                            user_data,
 237                                            G_IO_ERROR, G_IO_ERROR_PENDING,
 238                                            _("Stream has outstanding operation"));
 239       return;
 240     }
 241
 242   klass = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 243
 244   g_output_stream_set_pending (output_stream, TRUE);
 245   stream->priv->outstanding_callback = callback;
 246   g_object_ref (stream);
 247   klass->query_info_async (stream, attributes, io_priority, cancellable,
 248                               async_ready_callback_wrapper, user_data);
 249 }
 250
 251 /**
 252  * g_file_output_stream_query_info_finish:
 253  * @stream: a #GFileOutputStream.
 254  * @result: a #GAsyncResult.
 255  * @error: a #GError, %NULL to ignore.
 256  *
 257  * Finalizes the asynchronous query started
 258  * by g_file_output_stream_query_info_async().
 259  *
 260  * Returns: A #GFileInfo for the finished query.
 261  **/
 262 GFileInfo *
 263 g_file_output_stream_query_info_finish (GFileOutputStream     *stream,
 264                                            GAsyncResult         *result,
 265                                            GError              **error)
 266 {
 267   GSimpleAsyncResult *simple;
 268   GFileOutputStreamClass *class;
 269
 270   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), NULL);
 271   g_return_val_if_fail (G_IS_ASYNC_RESULT (result), NULL);
 272
 273   if (G_IS_SIMPLE_ASYNC_RESULT (result))
 274     {
 275       simple = G_SIMPLE_ASYNC_RESULT (result);
 276       if (g_simple_async_result_propagate_error (simple, error))
 277         return NULL;
 278     }
 279
 280   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 281   return class->query_info_finish (stream, result, error);
 282 }
 283
 284 /**
 285  * g_file_output_stream_get_etag:
 286  * @stream: a #GFileOutputStream.
 287  *
 288  * Gets the entity tag for the file output stream.
 289  *
 290  * Returns: the entity tag for the stream.
 291  **/
 292 char *
 293 g_file_output_stream_get_etag (GFileOutputStream  *stream)
 294 {
 295   GFileOutputStreamClass *class;
 296   GOutputStream *output_stream;
 297   char *etag;
 298
 299   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), NULL);
 300
 301   output_stream = G_OUTPUT_STREAM (stream);
 302
 303   if (!g_output_stream_is_closed (output_stream))
 304     {
 305       g_warning ("stream is not closed yet, can't get etag");
 306       return NULL;
 307     }
 308
 309   etag = NULL;
 310
 311   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 312   if (class->get_etag)
 313     etag = class->get_etag (stream);
 314
 315   return etag;
 316 }
 317
 318 /**
 319  * g_file_output_stream_tell:
 320  * @stream: a #GFileOutputStream.
 321  *
 322  * Gets the current location within the stream.
 323  *
 324  * Returns: a #goffset of the location within the stream.
 325  **/
 326 goffset
 327 g_file_output_stream_tell (GFileOutputStream  *stream)
 328 {
 329   GFileOutputStreamClass *class;
 330   goffset offset;
 331
 332   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), 0);
 333
 334   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 335
 336   offset = 0;
 337   if (class->tell)
 338     offset = class->tell (stream);
 339
 340   return offset;
 341 }
 342
 343 static goffset
 344 g_file_output_stream_seekable_tell (GSeekable *seekable)
 345 {
 346   return g_file_output_stream_tell (G_FILE_OUTPUT_STREAM (seekable));
 347 }
 348
 349 /**
 350  * g_file_output_stream_can_seek:
 351  * @stream: a #GFileOutputStream.
 352  *
 353  * Checks if the stream can be seeked.
 354  *
 355  * Returns: %TRUE if seeking is supported by the stream.
 356  **/
 357 gboolean
 358 g_file_output_stream_can_seek (GFileOutputStream  *stream)
 359 {
 360   GFileOutputStreamClass *class;
 361   gboolean can_seek;
 362
 363   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
 364
 365   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 366
 367   can_seek = FALSE;
 368   if (class->seek)
 369     {
 370       can_seek = TRUE;
 371       if (class->can_seek)
 372         can_seek = class->can_seek (stream);
 373     }
 374
 375   return can_seek;
 376 }
 377
 378 static gboolean
 379 g_file_output_stream_seekable_can_seek (GSeekable *seekable)
 380 {
 381   return g_file_output_stream_can_seek (G_FILE_OUTPUT_STREAM (seekable));
 382 }
 383
 384 /**
 385  * g_file_output_stream_seek:
 386  * @stream: a #GFileOutputStream.
 387  * @offset: a #goffset to seek.
 388  * @type: a #GSeekType.
 389  * @cancellable: optional #GCancellable object, %NULL to ignore.
 390  * @error: a #GError, %NULL to ignore.
 391  *
 392  * Seeks to a location in a file output stream.
 393  *
 394  * Returns: %TRUE if the seek was successful. %FALSE otherwise.
 395  **/
 396 gboolean
 397 g_file_output_stream_seek (GFileOutputStream  *stream,
 398                            goffset             offset,
 399                            GSeekType           type,
 400                            GCancellable       *cancellable,
 401                            GError            **error)
 402 {
 403   GFileOutputStreamClass *class;
 404   GOutputStream *output_stream;
 405   gboolean res;
 406
 407   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
 408
 409   output_stream = G_OUTPUT_STREAM (stream);
 410   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 411
 412   if (g_output_stream_is_closed (output_stream))
 413     {
 414       g_set_error (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
 415                    _("Stream is already closed"));
 416       return FALSE;
 417     }
 418
 419   if (g_output_stream_has_pending (output_stream))
 420     {
 421       g_set_error (error, G_IO_ERROR, G_IO_ERROR_PENDING,
 422                    _("Stream has outstanding operation"));
 423       return FALSE;
 424     }
 425
 426   if (!class->seek)
 427     {
 428       g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 429                    _("Seek not supported on stream"));
 430       return FALSE;
 431     }
 432
 433   g_output_stream_set_pending (output_stream, TRUE);
 434
 435   if (cancellable)
 436     g_push_current_cancellable (cancellable);
 437
 438   res = class->seek (stream, offset, type, cancellable, error);
 439
 440   if (cancellable)
 441     g_pop_current_cancellable (cancellable);
 442
 443   g_output_stream_set_pending (output_stream, FALSE);
 444
 445   return res;
 446 }
 447
 448 static gboolean
 449 g_file_output_stream_seekable_seek (GSeekable  *seekable,
 450                                     goffset     offset,
 451                                     GSeekType   type,
 452                                     GCancellable  *cancellable,
 453                                     GError    **error)
 454 {
 455   return g_file_output_stream_seek (G_FILE_OUTPUT_STREAM (seekable),
 456                                     offset, type, cancellable, error);
 457 }
 458
 459 /**
 460  * g_file_output_stream_can_truncate:
 461  * @stream: a #GFileOutputStream.
 462  *
 463  * Checks if the stream can be truncated.
 464  *
 465  * Returns: %TRUE if stream can be truncated.
 466  **/
 467 gboolean
 468 g_file_output_stream_can_truncate (GFileOutputStream  *stream)
 469 {
 470   GFileOutputStreamClass *class;
 471   gboolean can_truncate;
 472
 473   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
 474
 475   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 476
 477   can_truncate = FALSE;
 478   if (class->truncate)
 479     {
 480       can_truncate = TRUE;
 481       if (class->can_truncate)
 482         can_truncate = class->can_truncate (stream);
 483     }
 484
 485   return can_truncate;
 486 }
 487
 488 static gboolean
 489 g_file_output_stream_seekable_can_truncate (GSeekable  *seekable)
 490 {
 491   return g_file_output_stream_can_truncate (G_FILE_OUTPUT_STREAM (seekable));
 492 }
 493
 494 /**
 495  * g_file_output_stream_truncate:
 496  * @stream: a #GFileOutputStream.
 497  * @size: a #goffset to truncate the stream at.
 498  * @cancellable: optional #GCancellable object, %NULL to ignore.
 499  * @error: a #GError, %NULL to ignore.
 500  *
 501  * Truncates a file output stream.
 502  *
 503  * Returns: %TRUE if @stream is truncated successfully.
 504  **/
 505 gboolean
 506 g_file_output_stream_truncate (GFileOutputStream  *stream,
 507                                goffset             size,
 508                                GCancellable       *cancellable,
 509                                GError            **error)
 510 {
 511   GFileOutputStreamClass *class;
 512   GOutputStream *output_stream;
 513   gboolean res;
 514
 515   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
 516
 517   output_stream = G_OUTPUT_STREAM (stream);
 518   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 519
 520   if (g_output_stream_is_closed (output_stream))
 521     {
 522       g_set_error (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
 523                    _("Stream is already closed"));
 524       return FALSE;
 525     }
 526
 527   if (g_output_stream_has_pending (output_stream))
 528     {
 529       g_set_error (error, G_IO_ERROR, G_IO_ERROR_PENDING,
 530                    _("Stream has outstanding operation"));
 531       return FALSE;
 532     }
 533
 534   if (!class->truncate)
 535     {
 536       g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 537                    _("Truncate not supported on stream"));
 538       return FALSE;
 539     }
 540
 541   g_output_stream_set_pending (output_stream, TRUE);
 542
 543   if (cancellable)
 544     g_push_current_cancellable (cancellable);
 545
 546   res = class->truncate (stream, size, cancellable, error);
 547
 548   if (cancellable)
 549     g_pop_current_cancellable (cancellable);
 550
 551   g_output_stream_set_pending (output_stream, FALSE);
 552
 553   return res;
 554 }
 555
 556 static gboolean
 557 g_file_output_stream_seekable_truncate (GSeekable     *seekable,
 558                                         goffset        size,
 559                                         GCancellable  *cancellable,
 560                                         GError       **error)
 561 {
 562   return g_file_output_stream_truncate (G_FILE_OUTPUT_STREAM (seekable),
 563                                         size, cancellable, error);
 564 }
 565 /********************************************
 566  *   Default implementation of async ops    *
 567  ********************************************/
 568
 569 typedef struct {
 570   char *attributes;
 571   GFileInfo *info;
 572 } QueryInfoAsyncData;
 573
 574 static void
 575 query_info_data_free (QueryInfoAsyncData *data)
 576 {
 577   if (data->info)
 578     g_object_unref (data->info);
 579   g_free (data->attributes);
 580   g_free (data);
 581 }
 582
 583 static void
 584 query_info_async_thread (GSimpleAsyncResult *res,
 585                        GObject *object,
 586                        GCancellable *cancellable)
 587 {
 588   GFileOutputStreamClass *class;
 589   GError *error = NULL;
 590   QueryInfoAsyncData *data;
 591   GFileInfo *info;
 592
 593   data = g_simple_async_result_get_op_res_gpointer (res);
 594
 595   info = NULL;
 596
 597   class = G_FILE_OUTPUT_STREAM_GET_CLASS (object);
 598   if (class->query_info)
 599     info = class->query_info (G_FILE_OUTPUT_STREAM (object), data->attributes, cancellable, &error);
 600   else
 601     g_set_error (&error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 602                  _("Stream doesn't support query_info"));
 603
 604   if (info == NULL)
 605     {
 606       g_simple_async_result_set_from_error (res, error);
 607       g_error_free (error);
 608     }
 609   else
 610     data->info = info;
 611 }
 612
 613 static void
 614 g_file_output_stream_real_query_info_async (GFileOutputStream     *stream,
 615                                                char                 *attributes,
 616                                                int                   io_priority,
 617                                                GCancellable         *cancellable,
 618                                                GAsyncReadyCallback   callback,
 619                                                gpointer              user_data)
 620 {
 621   GSimpleAsyncResult *res;
 622   QueryInfoAsyncData *data;
 623
 624   data = g_new0 (QueryInfoAsyncData, 1);
 625   data->attributes = g_strdup (attributes);
 626
 627   res = g_simple_async_result_new (G_OBJECT (stream), callback, user_data, g_file_output_stream_real_query_info_async);
 628   g_simple_async_result_set_op_res_gpointer (res, data, (GDestroyNotify)query_info_data_free);
 629
 630   g_simple_async_result_run_in_thread (res, query_info_async_thread, io_priority, cancellable);
 631   g_object_unref (res);
 632 }
 633
 634 static GFileInfo *
 635 g_file_output_stream_real_query_info_finish (GFileOutputStream     *stream,
 636                                                 GAsyncResult         *res,
 637                                                 GError              **error)
 638 {
 639   GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (res);
 640   QueryInfoAsyncData *data;
 641
 642   g_assert (g_simple_async_result_get_source_tag (simple) == g_file_output_stream_real_query_info_async);
 643
 644   data = g_simple_async_result_get_op_res_gpointer (simple);
 645   if (data->info)
 646     return g_object_ref (data->info);
 647
 648   return NULL;
 649 }
 650
 651 #define __G_FILE_OUTPUT_STREAM_C__
 652 #include "gioaliasdef.c"