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_cancellable_push_current (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_cancellable_pop_current (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 when its been written.
 267  * This must be called after the stream has been written
 268  * and closed. As the etag can change while writing.
 269  *
 270  * Returns: the entity tag for the stream.
 271  **/
 272 char *
 273 g_file_output_stream_get_etag (GFileOutputStream  *stream)
 274 {
 275   GFileOutputStreamClass *class;
 276   GOutputStream *output_stream;
 277   char *etag;
 278
 279   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), NULL);
 280
 281   output_stream = G_OUTPUT_STREAM (stream);
 282
 283   if (!g_output_stream_is_closed (output_stream))
 284     {
 285       g_warning ("stream is not closed yet, can't get etag");
 286       return NULL;
 287     }
 288
 289   etag = NULL;
 290
 291   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 292   if (class->get_etag)
 293     etag = class->get_etag (stream);
 294
 295   return etag;
 296 }
 297
 298 /**
 299  * g_file_output_stream_tell:
 300  * @stream: a #GFileOutputStream.
 301  *
 302  * Gets the current location within the stream.
 303  *
 304  * Returns: a #goffset of the location within the stream.
 305  **/
 306 goffset
 307 g_file_output_stream_tell (GFileOutputStream  *stream)
 308 {
 309   GFileOutputStreamClass *class;
 310   goffset offset;
 311
 312   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), 0);
 313
 314   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 315
 316   offset = 0;
 317   if (class->tell)
 318     offset = class->tell (stream);
 319
 320   return offset;
 321 }
 322
 323 static goffset
 324 g_file_output_stream_seekable_tell (GSeekable *seekable)
 325 {
 326   return g_file_output_stream_tell (G_FILE_OUTPUT_STREAM (seekable));
 327 }
 328
 329 /**
 330  * g_file_output_stream_can_seek:
 331  * @stream: a #GFileOutputStream.
 332  *
 333  * Checks if the stream can be seeked.
 334  *
 335  * Returns: %TRUE if seeking is supported by the stream.
 336  **/
 337 gboolean
 338 g_file_output_stream_can_seek (GFileOutputStream  *stream)
 339 {
 340   GFileOutputStreamClass *class;
 341   gboolean can_seek;
 342
 343   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
 344
 345   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 346
 347   can_seek = FALSE;
 348   if (class->seek)
 349     {
 350       can_seek = TRUE;
 351       if (class->can_seek)
 352         can_seek = class->can_seek (stream);
 353     }
 354
 355   return can_seek;
 356 }
 357
 358 static gboolean
 359 g_file_output_stream_seekable_can_seek (GSeekable *seekable)
 360 {
 361   return g_file_output_stream_can_seek (G_FILE_OUTPUT_STREAM (seekable));
 362 }
 363
 364 /**
 365  * g_file_output_stream_seek:
 366  * @stream: a #GFileOutputStream.
 367  * @offset: a #goffset to seek.
 368  * @type: a #GSeekType.
 369  * @cancellable: optional #GCancellable object, %NULL to ignore.
 370  * @error: a #GError, %NULL to ignore.
 371  *
 372  * Seeks to a location in a file output stream.
 373  *
 374  * Returns: %TRUE if the seek was successful. %FALSE otherwise.
 375  **/
 376 gboolean
 377 g_file_output_stream_seek (GFileOutputStream  *stream,
 378                            goffset             offset,
 379                            GSeekType           type,
 380                            GCancellable       *cancellable,
 381                            GError            **error)
 382 {
 383   GFileOutputStreamClass *class;
 384   GOutputStream *output_stream;
 385   gboolean res;
 386
 387   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
 388
 389   output_stream = G_OUTPUT_STREAM (stream);
 390   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 391
 392   if (!class->seek)
 393     {
 394       g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 395                    _("Seek not supported on stream"));
 396       return FALSE;
 397     }
 398
 399   if (!g_output_stream_set_pending (output_stream, error))
 400     return FALSE;
 401
 402   if (cancellable)
 403     g_cancellable_push_current (cancellable);
 404
 405   res = class->seek (stream, offset, type, cancellable, error);
 406
 407   if (cancellable)
 408     g_cancellable_pop_current (cancellable);
 409
 410   g_output_stream_clear_pending (output_stream);
 411
 412   return res;
 413 }
 414
 415 static gboolean
 416 g_file_output_stream_seekable_seek (GSeekable  *seekable,
 417                                     goffset     offset,
 418                                     GSeekType   type,
 419                                     GCancellable  *cancellable,
 420                                     GError    **error)
 421 {
 422   return g_file_output_stream_seek (G_FILE_OUTPUT_STREAM (seekable),
 423                                     offset, type, cancellable, error);
 424 }
 425
 426 /**
 427  * g_file_output_stream_can_truncate:
 428  * @stream: a #GFileOutputStream.
 429  *
 430  * Checks if the stream can be truncated.
 431  *
 432  * Returns: %TRUE if stream can be truncated.
 433  **/
 434 gboolean
 435 g_file_output_stream_can_truncate (GFileOutputStream  *stream)
 436 {
 437   GFileOutputStreamClass *class;
 438   gboolean can_truncate;
 439
 440   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
 441
 442   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 443
 444   can_truncate = FALSE;
 445   if (class->truncate_fn)
 446     {
 447       can_truncate = TRUE;
 448       if (class->can_truncate)
 449         can_truncate = class->can_truncate (stream);
 450     }
 451
 452   return can_truncate;
 453 }
 454
 455 static gboolean
 456 g_file_output_stream_seekable_can_truncate (GSeekable  *seekable)
 457 {
 458   return g_file_output_stream_can_truncate (G_FILE_OUTPUT_STREAM (seekable));
 459 }
 460
 461 /**
 462  * g_file_output_stream_truncate:
 463  * @stream: a #GFileOutputStream.
 464  * @size: a #goffset to truncate the stream at.
 465  * @cancellable: optional #GCancellable object, %NULL to ignore.
 466  * @error: a #GError, %NULL to ignore.
 467  *
 468  * Truncates a file output stream.
 469  *
 470  * Returns: %TRUE if @stream is truncated successfully.
 471  **/
 472 gboolean
 473 g_file_output_stream_truncate (GFileOutputStream  *stream,
 474                                goffset             size,
 475                                GCancellable       *cancellable,
 476                                GError            **error)
 477 {
 478   GFileOutputStreamClass *class;
 479   GOutputStream *output_stream;
 480   gboolean res;
 481
 482   g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);
 483
 484   output_stream = G_OUTPUT_STREAM (stream);
 485   class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);
 486
 487   if (!class->truncate_fn)
 488     {
 489       g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 490                    _("Truncate not supported on stream"));
 491       return FALSE;
 492     }
 493
 494   if (!g_output_stream_set_pending (output_stream, error))
 495     return FALSE;
 496
 497   if (cancellable)
 498     g_cancellable_push_current (cancellable);
 499
 500   res = class->truncate_fn (stream, size, cancellable, error);
 501
 502   if (cancellable)
 503     g_cancellable_pop_current (cancellable);
 504
 505   g_output_stream_clear_pending (output_stream);
 506
 507   return res;
 508 }
 509
 510 static gboolean
 511 g_file_output_stream_seekable_truncate (GSeekable     *seekable,
 512                                         goffset        size,
 513                                         GCancellable  *cancellable,
 514                                         GError       **error)
 515 {
 516   return g_file_output_stream_truncate (G_FILE_OUTPUT_STREAM (seekable),
 517                                         size, cancellable, error);
 518 }
 519 /********************************************
 520  *   Default implementation of async ops    *
 521  ********************************************/
 522
 523 typedef struct {
 524   char *attributes;
 525   GFileInfo *info;
 526 } QueryInfoAsyncData;
 527
 528 static void
 529 query_info_data_free (QueryInfoAsyncData *data)
 530 {
 531   if (data->info)
 532     g_object_unref (data->info);
 533   g_free (data->attributes);
 534   g_free (data);
 535 }
 536
 537 static void
 538 query_info_async_thread (GSimpleAsyncResult *res,
 539                        GObject *object,
 540                        GCancellable *cancellable)
 541 {
 542   GFileOutputStreamClass *class;
 543   GError *error = NULL;
 544   QueryInfoAsyncData *data;
 545   GFileInfo *info;
 546
 547   data = g_simple_async_result_get_op_res_gpointer (res);
 548
 549   info = NULL;
 550
 551   class = G_FILE_OUTPUT_STREAM_GET_CLASS (object);
 552   if (class->query_info)
 553     info = class->query_info (G_FILE_OUTPUT_STREAM (object), data->attributes, cancellable, &error);
 554   else
 555     g_set_error (&error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 556                  _("Stream doesn't support query_info"));
 557
 558   if (info == NULL)
 559     {
 560       g_simple_async_result_set_from_error (res, error);
 561       g_error_free (error);
 562     }
 563   else
 564     data->info = info;
 565 }
 566
 567 static void
 568 g_file_output_stream_real_query_info_async (GFileOutputStream     *stream,
 569                                                char                 *attributes,
 570                                                int                   io_priority,
 571                                                GCancellable         *cancellable,
 572                                                GAsyncReadyCallback   callback,
 573                                                gpointer              user_data)
 574 {
 575   GSimpleAsyncResult *res;
 576   QueryInfoAsyncData *data;
 577
 578   data = g_new0 (QueryInfoAsyncData, 1);
 579   data->attributes = g_strdup (attributes);
 580
 581   res = g_simple_async_result_new (G_OBJECT (stream), callback, user_data, g_file_output_stream_real_query_info_async);
 582   g_simple_async_result_set_op_res_gpointer (res, data, (GDestroyNotify)query_info_data_free);
 583
 584   g_simple_async_result_run_in_thread (res, query_info_async_thread, io_priority, cancellable);
 585   g_object_unref (res);
 586 }
 587
 588 static GFileInfo *
 589 g_file_output_stream_real_query_info_finish (GFileOutputStream     *stream,
 590                                                 GAsyncResult         *res,
 591                                                 GError              **error)
 592 {
 593   GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (res);
 594   QueryInfoAsyncData *data;
 595
 596   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_file_output_stream_real_query_info_async);
 597
 598   data = g_simple_async_result_get_op_res_gpointer (simple);
 599   if (data->info)
 600     return g_object_ref (data->info);
 601
 602   return NULL;
 603 }
 604
 605 #define __G_FILE_OUTPUT_STREAM_C__
 606 #include "gioaliasdef.c"