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_fn = 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_set_pending (output_stream, error))
 142     return NULL;
 143
 144   info = NULL;
 145
 146   if (cancellable)
 147     g_push_current_cancellable (cancellable);
 148
 149   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 150   if (class->query_info)
 151     info = class->query_info (stream, attributes, cancellable, error);
 152   else
 153     g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 154                  _("Stream doesn't support query_info"));
 155
 156   if (cancellable)
 157     g_pop_current_cancellable (cancellable);
 158
 159   g_output_stream_clear_pending (output_stream);
 160
 161   return info;
 162 }
 163
 164 static void
 165 async_ready_callback_wrapper (GObject *source_object,
 166                               GAsyncResult *res,
 167                               gpointer      user_data)
 168 {
 169   GFileOutputStream *stream = G_FILE_OUTPUT_STREAM (source_object);
 170
 171   g_output_stream_clear_pending (G_OUTPUT_STREAM (stream));
 172   if (stream->priv->outstanding_callback)
 173     (*stream->priv->outstanding_callback) (source_object, res, user_data);
 174   g_object_unref (stream);
 175 }
 176
 177 /**
 178  * g_file_output_stream_query_info_async:
 179  * @stream: a #GFileOutputStream.
 180  * @attributes: a file attribute query string.
 181  * @io_priority: the <link linkend="gio-GIOScheduler">I/O priority</link>
 182  *     of the request.
 183  * @cancellable: optional #GCancellable object, %NULL to ignore.
 184  * @callback: callback to call when the request is satisfied
 185  * @user_data: the data to pass to callback function
 186  *
 187  * Asynchronously queries the @stream for a #GFileInfo. When completed,
 188  * @callback will be called with a #GAsyncResult which can be used to
 189  * finish the operation with g_file_output_stream_query_info_finish().
 190  *
 191  * For the synchronous version of this function, see
 192  * g_file_output_stream_query_info().
 193  *
 194  **/
 195 void
 196 g_file_output_stream_query_info_async (GFileOutputStream     *stream,
 197                                           char                 *attributes,
 198                                           int                   io_priority,
 199                                           GCancellable         *cancellable,
 200                                           GAsyncReadyCallback   callback,
 201                                           gpointer              user_data)
 202 {
 203   GFileOutputStreamClass *klass;
 204   GOutputStream *output_stream;
 205   GError *error = NULL;
 206
 207   g_return_if_fail (G_IS_FILE_OUTPUT_STREAM (stream));
 208
 209   output_stream = G_OUTPUT_STREAM (stream);
 210
 211   if (!g_output_stream_set_pending (output_stream, &error))
 212     {
 213       g_simple_async_report_gerror_in_idle (G_OBJECT (stream),
 214                                             callback,
 215                                             user_data,
 216                                             error);
 217       g_error_free (error);
 218       return;
 219     }
 220
 221   klass = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 222
 223   stream->priv->outstanding_callback = callback;
 224   g_object_ref (stream);
 225   klass->query_info_async (stream, attributes, io_priority, cancellable,
 226                               async_ready_callback_wrapper, user_data);
 227 }
 228
 229 /**
 230  * g_file_output_stream_query_info_finish:
 231  * @stream: a #GFileOutputStream.
 232  * @result: a #GAsyncResult.
 233  * @error: a #GError, %NULL to ignore.
 234  *
 235  * Finalizes the asynchronous query started
 236  * by g_file_output_stream_query_info_async().
 237  *
 238  * Returns: A #GFileInfo for the finished query.
 239  **/
 240 GFileInfo *
 241 g_file_output_stream_query_info_finish (GFileOutputStream     *stream,
 242                                            GAsyncResult         *result,
 243                                            GError              **error)
 244 {
 245   GSimpleAsyncResult *simple;
 246   GFileOutputStreamClass *class;
 247
 248   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), NULL);
 249   g_return_val_if_fail (G_IS_ASYNC_RESULT (result), NULL);
 250
 251   if (G_IS_SIMPLE_ASYNC_RESULT (result))
 252     {
 253       simple = G_SIMPLE_ASYNC_RESULT (result);
 254       if (g_simple_async_result_propagate_error (simple, error))
 255         return NULL;
 256     }
 257
 258   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 259   return class->query_info_finish (stream, result, error);
 260 }
 261
 262 /**
 263  * g_file_output_stream_get_etag:
 264  * @stream: a #GFileOutputStream.
 265  *
 266  * Gets the entity tag for the file output stream.
 267  *
 268  * Returns: the entity tag for the stream.
 269  **/
 270 char *
 271 g_file_output_stream_get_etag (GFileOutputStream  *stream)
 272 {
 273   GFileOutputStreamClass *class;
 274   GOutputStream *output_stream;
 275   char *etag;
 276
 277   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), NULL);
 278
 279   output_stream = G_OUTPUT_STREAM (stream);
 280
 281   if (!g_output_stream_is_closed (output_stream))
 282     {
 283       g_warning ("stream is not closed yet, can't get etag");
 284       return NULL;
 285     }
 286
 287   etag = NULL;
 288
 289   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 290   if (class->get_etag)
 291     etag = class->get_etag (stream);
 292
 293   return etag;
 294 }
 295
 296 /**
 297  * g_file_output_stream_tell:
 298  * @stream: a #GFileOutputStream.
 299  *
 300  * Gets the current location within the stream.
 301  *
 302  * Returns: a #goffset of the location within the stream.
 303  **/
 304 goffset
 305 g_file_output_stream_tell (GFileOutputStream  *stream)
 306 {
 307   GFileOutputStreamClass *class;
 308   goffset offset;
 309
 310   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), 0);
 311
 312   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 313
 314   offset = 0;
 315   if (class->tell)
 316     offset = class->tell (stream);
 317
 318   return offset;
 319 }
 320
 321 static goffset
 322 g_file_output_stream_seekable_tell (GSeekable *seekable)
 323 {
 324   return g_file_output_stream_tell (G_FILE_OUTPUT_STREAM (seekable));
 325 }
 326
 327 /**
 328  * g_file_output_stream_can_seek:
 329  * @stream: a #GFileOutputStream.
 330  *
 331  * Checks if the stream can be seeked.
 332  *
 333  * Returns: %TRUE if seeking is supported by the stream.
 334  **/
 335 gboolean
 336 g_file_output_stream_can_seek (GFileOutputStream  *stream)
 337 {
 338   GFileOutputStreamClass *class;
 339   gboolean can_seek;
 340
 341   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
 342
 343   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 344
 345   can_seek = FALSE;
 346   if (class->seek)
 347     {
 348       can_seek = TRUE;
 349       if (class->can_seek)
 350         can_seek = class->can_seek (stream);
 351     }
 352
 353   return can_seek;
 354 }
 355
 356 static gboolean
 357 g_file_output_stream_seekable_can_seek (GSeekable *seekable)
 358 {
 359   return g_file_output_stream_can_seek (G_FILE_OUTPUT_STREAM (seekable));
 360 }
 361
 362 /**
 363  * g_file_output_stream_seek:
 364  * @stream: a #GFileOutputStream.
 365  * @offset: a #goffset to seek.
 366  * @type: a #GSeekType.
 367  * @cancellable: optional #GCancellable object, %NULL to ignore.
 368  * @error: a #GError, %NULL to ignore.
 369  *
 370  * Seeks to a location in a file output stream.
 371  *
 372  * Returns: %TRUE if the seek was successful. %FALSE otherwise.
 373  **/
 374 gboolean
 375 g_file_output_stream_seek (GFileOutputStream  *stream,
 376                            goffset             offset,
 377                            GSeekType           type,
 378                            GCancellable       *cancellable,
 379                            GError            **error)
 380 {
 381   GFileOutputStreamClass *class;
 382   GOutputStream *output_stream;
 383   gboolean res;
 384
 385   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
 386
 387   output_stream = G_OUTPUT_STREAM (stream);
 388   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 389
 390   if (!class->seek)
 391     {
 392       g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 393                    _("Seek not supported on stream"));
 394       return FALSE;
 395     }
 396
 397   if (!g_output_stream_set_pending (output_stream, error))
 398     return FALSE;
 399
 400   if (cancellable)
 401     g_push_current_cancellable (cancellable);
 402
 403   res = class->seek (stream, offset, type, cancellable, error);
 404
 405   if (cancellable)
 406     g_pop_current_cancellable (cancellable);
 407
 408   g_output_stream_clear_pending (output_stream);
 409
 410   return res;
 411 }
 412
 413 static gboolean
 414 g_file_output_stream_seekable_seek (GSeekable  *seekable,
 415                                     goffset     offset,
 416                                     GSeekType   type,
 417                                     GCancellable  *cancellable,
 418                                     GError    **error)
 419 {
 420   return g_file_output_stream_seek (G_FILE_OUTPUT_STREAM (seekable),
 421                                     offset, type, cancellable, error);
 422 }
 423
 424 /**
 425  * g_file_output_stream_can_truncate:
 426  * @stream: a #GFileOutputStream.
 427  *
 428  * Checks if the stream can be truncated.
 429  *
 430  * Returns: %TRUE if stream can be truncated.
 431  **/
 432 gboolean
 433 g_file_output_stream_can_truncate (GFileOutputStream  *stream)
 434 {
 435   GFileOutputStreamClass *class;
 436   gboolean can_truncate;
 437
 438   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
 439
 440   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 441
 442   can_truncate = FALSE;
 443   if (class->truncate_fn)
 444     {
 445       can_truncate = TRUE;
 446       if (class->can_truncate)
 447         can_truncate = class->can_truncate (stream);
 448     }
 449
 450   return can_truncate;
 451 }
 452
 453 static gboolean
 454 g_file_output_stream_seekable_can_truncate (GSeekable  *seekable)
 455 {
 456   return g_file_output_stream_can_truncate (G_FILE_OUTPUT_STREAM (seekable));
 457 }
 458
 459 /**
 460  * g_file_output_stream_truncate:
 461  * @stream: a #GFileOutputStream.
 462  * @size: a #goffset to truncate the stream at.
 463  * @cancellable: optional #GCancellable object, %NULL to ignore.
 464  * @error: a #GError, %NULL to ignore.
 465  *
 466  * Truncates a file output stream.
 467  *
 468  * Returns: %TRUE if @stream is truncated successfully.
 469  **/
 470 gboolean
 471 g_file_output_stream_truncate (GFileOutputStream  *stream,
 472                                goffset             size,
 473                                GCancellable       *cancellable,
 474                                GError            **error)
 475 {
 476   GFileOutputStreamClass *class;
 477   GOutputStream *output_stream;
 478   gboolean res;
 479
 480   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
 481
 482   output_stream = G_OUTPUT_STREAM (stream);
 483   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 484
 485   if (!class->truncate_fn)
 486     {
 487       g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 488                    _("Truncate not supported on stream"));
 489       return FALSE;
 490     }
 491
 492   if (!g_output_stream_set_pending (output_stream, error))
 493     return FALSE;
 494
 495   if (cancellable)
 496     g_push_current_cancellable (cancellable);
 497
 498   res = class->truncate_fn (stream, size, cancellable, error);
 499
 500   if (cancellable)
 501     g_pop_current_cancellable (cancellable);
 502
 503   g_output_stream_clear_pending (output_stream);
 504
 505   return res;
 506 }
 507
 508 static gboolean
 509 g_file_output_stream_seekable_truncate (GSeekable     *seekable,
 510                                         goffset        size,
 511                                         GCancellable  *cancellable,
 512                                         GError       **error)
 513 {
 514   return g_file_output_stream_truncate (G_FILE_OUTPUT_STREAM (seekable),
 515                                         size, cancellable, error);
 516 }
 517 /********************************************
 518  *   Default implementation of async ops    *
 519  ********************************************/
 520
 521 typedef struct {
 522   char *attributes;
 523   GFileInfo *info;
 524 } QueryInfoAsyncData;
 525
 526 static void
 527 query_info_data_free (QueryInfoAsyncData *data)
 528 {
 529   if (data->info)
 530     g_object_unref (data->info);
 531   g_free (data->attributes);
 532   g_free (data);
 533 }
 534
 535 static void
 536 query_info_async_thread (GSimpleAsyncResult *res,
 537                        GObject *object,
 538                        GCancellable *cancellable)
 539 {
 540   GFileOutputStreamClass *class;
 541   GError *error = NULL;
 542   QueryInfoAsyncData *data;
 543   GFileInfo *info;
 544
 545   data = g_simple_async_result_get_op_res_gpointer (res);
 546
 547   info = NULL;
 548
 549   class = G_FILE_OUTPUT_STREAM_GET_CLASS (object);
 550   if (class->query_info)
 551     info = class->query_info (G_FILE_OUTPUT_STREAM (object), data->attributes, cancellable, &error);
 552   else
 553     g_set_error (&error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 554                  _("Stream doesn't support query_info"));
 555
 556   if (info == NULL)
 557     {
 558       g_simple_async_result_set_from_error (res, error);
 559       g_error_free (error);
 560     }
 561   else
 562     data->info = info;
 563 }
 564
 565 static void
 566 g_file_output_stream_real_query_info_async (GFileOutputStream     *stream,
 567                                                char                 *attributes,
 568                                                int                   io_priority,
 569                                                GCancellable         *cancellable,
 570                                                GAsyncReadyCallback   callback,
 571                                                gpointer              user_data)
 572 {
 573   GSimpleAsyncResult *res;
 574   QueryInfoAsyncData *data;
 575
 576   data = g_new0 (QueryInfoAsyncData, 1);
 577   data->attributes = g_strdup (attributes);
 578
 579   res = g_simple_async_result_new (G_OBJECT (stream), callback, user_data, g_file_output_stream_real_query_info_async);
 580   g_simple_async_result_set_op_res_gpointer (res, data, (GDestroyNotify)query_info_data_free);
 581
 582   g_simple_async_result_run_in_thread (res, query_info_async_thread, io_priority, cancellable);
 583   g_object_unref (res);
 584 }
 585
 586 static GFileInfo *
 587 g_file_output_stream_real_query_info_finish (GFileOutputStream     *stream,
 588                                                 GAsyncResult         *res,
 589                                                 GError              **error)
 590 {
 591   GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (res);
 592   QueryInfoAsyncData *data;
 593
 594   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_file_output_stream_real_query_info_async);
 595
 596   data = g_simple_async_result_get_op_res_gpointer (simple);
 597   if (data->info)
 598     return g_object_ref (data->info);
 599
 600   return NULL;
 601 }
 602
 603 #define __G_FILE_OUTPUT_STREAM_C__
 604 #include "gioaliasdef.c"