gio/gfileinputstream.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 <gfileinputstream.h>
  27 #include <gseekable.h>
  28 #include "gsimpleasyncresult.h"
  29 #include "glibintl.h"
  30
  31 #include "gioalias.h"
  32
  33 /**
  34  * SECTION:gfileinputstream
  35  * @short_description: file input streaming operations
  36  * @see_also: #GInputStream, #GDataInputStream, #GSeekable
  37  *
  38  *
  39  *
  40  **/
  41
  42 static void       g_file_input_stream_seekable_iface_init    (GSeekableIface       *iface);
  43 static goffset    g_file_input_stream_seekable_tell          (GSeekable            *seekable);
  44 static gboolean   g_file_input_stream_seekable_can_seek      (GSeekable            *seekable);
  45 static gboolean   g_file_input_stream_seekable_seek          (GSeekable            *seekable,
  46                                                               goffset               offset,
  47                                                               GSeekType             type,
  48                                                               GCancellable         *cancellable,
  49                                                               GError              **error);
  50 static gboolean   g_file_input_stream_seekable_can_truncate  (GSeekable            *seekable);
  51 static gboolean   g_file_input_stream_seekable_truncate      (GSeekable            *seekable,
  52                                                               goffset               offset,
  53                                                               GCancellable         *cancellable,
  54                                                               GError              **error);
  55 static void       g_file_input_stream_real_query_info_async  (GFileInputStream     *stream,
  56                                                               char                 *attributes,
  57                                                               int                   io_priority,
  58                                                               GCancellable         *cancellable,
  59                                                               GAsyncReadyCallback   callback,
  60                                                               gpointer              user_data);
  61 static GFileInfo *g_file_input_stream_real_query_info_finish (GFileInputStream     *stream,
  62                                                               GAsyncResult         *result,
  63                                                               GError              **error);
  64
  65
  66 G_DEFINE_TYPE_WITH_CODE (GFileInputStream, g_file_input_stream, G_TYPE_INPUT_STREAM,
  67                          G_IMPLEMENT_INTERFACE (G_TYPE_SEEKABLE,
  68                                                 g_file_input_stream_seekable_iface_init))
  69
  70 struct _GFileInputStreamPrivate {
  71   GAsyncReadyCallback outstanding_callback;
  72 };
  73
  74 static void
  75 g_file_input_stream_class_init (GFileInputStreamClass *klass)
  76 {
  77   g_type_class_add_private (klass, sizeof (GFileInputStreamPrivate));
  78
  79   klass->query_info_async = g_file_input_stream_real_query_info_async;
  80   klass->query_info_finish = g_file_input_stream_real_query_info_finish;
  81 }
  82
  83 static void
  84 g_file_input_stream_seekable_iface_init (GSeekableIface *iface)
  85 {
  86   iface->tell = g_file_input_stream_seekable_tell;
  87   iface->can_seek = g_file_input_stream_seekable_can_seek;
  88   iface->seek = g_file_input_stream_seekable_seek;
  89   iface->can_truncate = g_file_input_stream_seekable_can_truncate;
  90   iface->truncate = g_file_input_stream_seekable_truncate;
  91 }
  92
  93 static void
  94 g_file_input_stream_init (GFileInputStream *stream)
  95 {
  96   stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (stream,
  97                                               G_TYPE_FILE_INPUT_STREAM,
  98                                               GFileInputStreamPrivate);
  99 }
 100
 101 /**
 102  * g_file_input_stream_query_info:
 103  * @stream: a #GFileInputStream.
 104  * @attributes: a file attribute query string.
 105  * @cancellable: optional #GCancellable object, %NULL to ignore.
 106  * @error: a #GError location to store the error occuring, or %NULL to
 107  * ignore.
 108  *
 109  * Queries a file input stream the given @attributes.his function blocks
 110  * while querying the stream. For the asynchronous (non-blocking) version
 111  * of this function, see g_file_input_stream_query_info_async(). While the
 112  * stream is blocked, the stream will set the pending flag internally, and
 113  * any other operations on the stream will fail with %G_IO_ERROR_PENDING.
 114  *
 115  * Returns: a #GFileInfo, or %NULL on error.
 116  **/
 117 GFileInfo *
 118 g_file_input_stream_query_info (GFileInputStream  *stream,
 119                                 char              *attributes,
 120                                 GCancellable      *cancellable,
 121                                 GError           **error)
 122 {
 123   GFileInputStreamClass *class;
 124   GInputStream *input_stream;
 125   GFileInfo *info;
 126
 127   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), NULL);
 128
 129   input_stream = G_INPUT_STREAM (stream);
 130
 131   if (g_input_stream_is_closed (input_stream))
 132     {
 133       g_set_error (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
 134                    _("Stream is already closed"));
 135       return NULL;
 136     }
 137
 138   if (g_input_stream_has_pending (input_stream))
 139     {
 140       g_set_error (error, G_IO_ERROR, G_IO_ERROR_PENDING,
 141                    _("Stream has outstanding operation"));
 142       return NULL;
 143     }
 144
 145   info = NULL;
 146
 147   g_input_stream_set_pending (input_stream, TRUE);
 148
 149   if (cancellable)
 150     g_push_current_cancellable (cancellable);
 151
 152   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 153   if (class->query_info)
 154     info = class->query_info (stream, attributes, cancellable, error);
 155   else
 156     g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 157                  _("Stream doesn't support query_info"));
 158
 159   if (cancellable)
 160     g_pop_current_cancellable (cancellable);
 161
 162   g_input_stream_set_pending (input_stream, FALSE);
 163
 164   return info;
 165 }
 166
 167 static void
 168 async_ready_callback_wrapper (GObject      *source_object,
 169                               GAsyncResult *res,
 170                               gpointer      user_data)
 171 {
 172   GFileInputStream *stream = G_FILE_INPUT_STREAM (source_object);
 173
 174   g_input_stream_set_pending (G_INPUT_STREAM (stream), FALSE);
 175   if (stream->priv->outstanding_callback)
 176     (*stream->priv->outstanding_callback) (source_object, res, user_data);
 177   g_object_unref (stream);
 178 }
 179
 180 /**
 181  * g_file_input_stream_query_info_async:
 182  * @stream: a #GFileInputStream.
 183  * @attributes: a file attribute query string.
 184  * @io_priority: the i/o priority of the request.
 185  * @cancellable: optional #GCancellable object, %NULL to ignore.
 186  * @callback: callback to call when the request is satisfied
 187  * @user_data: the data to pass to callback function
 188  *
 189  * Queries the stream information asynchronously. For the synchronous
 190  * version of this function, see g_file_input_stream_query_info().
 191  *
 192  * If @cancellable is not %NULL, then the operation can be cancelled by
 193  * triggering the cancellable object from another thread. If the operation
 194  * was cancelled, the error %G_IO_ERROR_CANCELLED will be set
 195  *
 196  **/
 197 void
 198 g_file_input_stream_query_info_async (GFileInputStream    *stream,
 199                                       char                *attributes,
 200                                       int                  io_priority,
 201                                       GCancellable        *cancellable,
 202                                       GAsyncReadyCallback  callback,
 203                                       gpointer             user_data)
 204 {
 205   GFileInputStreamClass *klass;
 206   GInputStream *input_stream;
 207
 208   g_return_if_fail (G_IS_FILE_INPUT_STREAM (stream));
 209
 210   input_stream = G_INPUT_STREAM (stream);
 211
 212   if (g_input_stream_is_closed (input_stream))
 213     {
 214       g_simple_async_report_error_in_idle (G_OBJECT (stream),
 215                                            callback,
 216                                            user_data,
 217                                            G_IO_ERROR, G_IO_ERROR_CLOSED,
 218                                            _("Stream is already closed"));
 219       return;
 220     }
 221
 222   if (g_input_stream_has_pending (input_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_PENDING,
 228                                            _("Stream has outstanding operation"));
 229       return;
 230     }
 231
 232   klass = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 233
 234   g_input_stream_set_pending (input_stream, TRUE);
 235   stream->priv->outstanding_callback = callback;
 236   g_object_ref (stream);
 237   klass->query_info_async (stream, attributes, io_priority, cancellable,
 238                               async_ready_callback_wrapper, user_data);
 239 }
 240
 241 /**
 242  * g_file_input_stream_query_info_finish:
 243  * @stream: a #GFileInputStream.
 244  * @result: a #GAsyncResult.
 245  * @error: a #GError location to store the error occuring,
 246  *     or %NULL to ignore.
 247  *
 248  * Finishes an asynchronous info query operation.
 249  *
 250  * Returns: #GFileInfo.
 251  **/
 252 GFileInfo *
 253 g_file_input_stream_query_info_finish (GFileInputStream  *stream,
 254                                        GAsyncResult      *result,
 255                                        GError           **error)
 256 {
 257   GSimpleAsyncResult *simple;
 258   GFileInputStreamClass *class;
 259
 260   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), NULL);
 261   g_return_val_if_fail (G_IS_ASYNC_RESULT (result), NULL);
 262
 263   if (G_IS_SIMPLE_ASYNC_RESULT (result))
 264     {
 265       simple = G_SIMPLE_ASYNC_RESULT (result);
 266       if (g_simple_async_result_propagate_error (simple, error))
 267         return NULL;
 268     }
 269
 270   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 271   return class->query_info_finish (stream, result, error);
 272 }
 273
 274 /**
 275  * g_file_input_stream_tell:
 276  * @stream: a #GFileInputStream.
 277  *
 278  * Gets the current position in the stream.
 279  *
 280  * Returns: a #goffset with the position in the stream.
 281  **/
 282 goffset
 283 g_file_input_stream_tell (GFileInputStream *stream)
 284 {
 285   GFileInputStreamClass *class;
 286   goffset offset;
 287
 288   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), 0);
 289
 290   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 291
 292   offset = 0;
 293   if (class->tell)
 294     offset = class->tell (stream);
 295
 296   return offset;
 297 }
 298
 299 static goffset
 300 g_file_input_stream_seekable_tell (GSeekable *seekable)
 301 {
 302   return g_file_input_stream_tell (G_FILE_INPUT_STREAM (seekable));
 303 }
 304
 305 /**
 306  * g_file_input_stream_can_seek:
 307  * @stream: a #GFileInputStream.
 308  *
 309  * Checks if a file input stream can be seeked.
 310  *
 311  * Returns: %TRUE if stream can be seeked. %FALSE otherwise.
 312  **/
 313 gboolean
 314 g_file_input_stream_can_seek (GFileInputStream *stream)
 315 {
 316   GFileInputStreamClass *class;
 317   gboolean can_seek;
 318
 319   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), FALSE);
 320
 321   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 322
 323   can_seek = FALSE;
 324   if (class->seek)
 325     {
 326       can_seek = TRUE;
 327       if (class->can_seek)
 328         can_seek = class->can_seek (stream);
 329     }
 330
 331   return can_seek;
 332 }
 333
 334 static gboolean
 335 g_file_input_stream_seekable_can_seek (GSeekable *seekable)
 336 {
 337   return g_file_input_stream_can_seek (G_FILE_INPUT_STREAM (seekable));
 338 }
 339
 340 /**
 341  * g_file_input_stream_seek:
 342  * @stream: a #GFileInputStream.
 343  * @offset: a #goffset to seek.
 344  * @type: a #GSeekType.
 345  * @cancellable: optional #GCancellable object, %NULL to ignore.
 346  * @error: a #GError location to store the error occuring, or
 347  *     %NULL to ignore.
 348  *
 349  * Seeks in the file input stream.
 350  *
 351  * If @cancellable is not %NULL, then the operation can be cancelled by
 352  * triggering the cancellable object from another thread. If the operation
 353  * was cancelled, the error %G_IO_ERROR_CANCELLED will be set.
 354  *
 355  * Returns: %TRUE if the stream was successfully seeked to the position.
 356  * %FALSE on error.
 357  **/
 358 gboolean
 359 g_file_input_stream_seek (GFileInputStream  *stream,
 360                           goffset            offset,
 361                           GSeekType          type,
 362                           GCancellable      *cancellable,
 363                           GError           **error)
 364 {
 365   GFileInputStreamClass *class;
 366   GInputStream *input_stream;
 367   gboolean res;
 368
 369   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), FALSE);
 370
 371   input_stream = G_INPUT_STREAM (stream);
 372   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 373
 374   if (g_input_stream_is_closed (input_stream))
 375     {
 376       g_set_error (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
 377                    _("Stream is already closed"));
 378       return FALSE;
 379     }
 380
 381   if (g_input_stream_has_pending (input_stream))
 382     {
 383       g_set_error (error, G_IO_ERROR, G_IO_ERROR_PENDING,
 384                    _("Stream has outstanding operation"));
 385       return FALSE;
 386     }
 387
 388   if (!class->seek)
 389     {
 390       g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 391                    _("Seek not supported on stream"));
 392       return FALSE;
 393     }
 394
 395   g_input_stream_set_pending (input_stream, TRUE);
 396
 397   if (cancellable)
 398     g_push_current_cancellable (cancellable);
 399
 400   res = class->seek (stream, offset, type, cancellable, error);
 401
 402   if (cancellable)
 403     g_pop_current_cancellable (cancellable);
 404
 405   g_input_stream_set_pending (input_stream, FALSE);
 406
 407   return res;
 408 }
 409
 410 static gboolean
 411 g_file_input_stream_seekable_seek (GSeekable     *seekable,
 412                                    goffset        offset,
 413                                    GSeekType      type,
 414                                    GCancellable  *cancellable,
 415                                    GError       **error)
 416 {
 417   return g_file_input_stream_seek (G_FILE_INPUT_STREAM (seekable),
 418                                    offset, type, cancellable, error);
 419 }
 420
 421 static gboolean
 422 g_file_input_stream_seekable_can_truncate (GSeekable *seekable)
 423 {
 424   return FALSE;
 425 }
 426
 427 static gboolean
 428 g_file_input_stream_seekable_truncate (GSeekable     *seekable,
 429                                        goffset        offset,
 430                                        GCancellable  *cancellable,
 431                                        GError       **error)
 432 {
 433   g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 434                _("Truncate not allowed on input stream"));
 435   return FALSE;
 436 }
 437
 438 /********************************************
 439  *   Default implementation of async ops    *
 440  ********************************************/
 441
 442 typedef struct {
 443   char *attributes;
 444   GFileInfo *info;
 445 } QueryInfoAsyncData;
 446
 447 static void
 448 query_info_data_free (QueryInfoAsyncData *data)
 449 {
 450   if (data->info)
 451     g_object_unref (data->info);
 452   g_free (data->attributes);
 453   g_free (data);
 454 }
 455
 456 static void
 457 query_info_async_thread (GSimpleAsyncResult *res,
 458                          GObject            *object,
 459                          GCancellable       *cancellable)
 460 {
 461   GFileInputStreamClass *class;
 462   GError *error = NULL;
 463   QueryInfoAsyncData *data;
 464   GFileInfo *info;
 465
 466   data = g_simple_async_result_get_op_res_gpointer (res);
 467
 468   info = NULL;
 469
 470   class = G_FILE_INPUT_STREAM_GET_CLASS (object);
 471   if (class->query_info)
 472     info = class->query_info (G_FILE_INPUT_STREAM (object), data->attributes, cancellable, &error);
 473   else
 474     g_set_error (&error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 475                  _("Stream doesn't support query_info"));
 476
 477   if (info == NULL)
 478     {
 479       g_simple_async_result_set_from_error (res, error);
 480       g_error_free (error);
 481     }
 482   else
 483     data->info = info;
 484 }
 485
 486 static void
 487 g_file_input_stream_real_query_info_async (GFileInputStream    *stream,
 488                                            char                *attributes,
 489                                            int                  io_priority,
 490                                            GCancellable        *cancellable,
 491                                            GAsyncReadyCallback  callback,
 492                                            gpointer             user_data)
 493 {
 494   GSimpleAsyncResult *res;
 495   QueryInfoAsyncData *data;
 496
 497   data = g_new0 (QueryInfoAsyncData, 1);
 498   data->attributes = g_strdup (attributes);
 499
 500   res = g_simple_async_result_new (G_OBJECT (stream), callback, user_data, g_file_input_stream_real_query_info_async);
 501   g_simple_async_result_set_op_res_gpointer (res, data, (GDestroyNotify)query_info_data_free);
 502
 503   g_simple_async_result_run_in_thread (res, query_info_async_thread, io_priority, cancellable);
 504   g_object_unref (res);
 505 }
 506
 507 static GFileInfo *
 508 g_file_input_stream_real_query_info_finish (GFileInputStream  *stream,
 509                                             GAsyncResult      *res,
 510                                             GError           **error)
 511 {
 512   GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (res);
 513   QueryInfoAsyncData *data;
 514
 515   g_assert (g_simple_async_result_get_source_tag (simple) == g_file_input_stream_real_query_info_async);
 516
 517   data = g_simple_async_result_get_op_res_gpointer (simple);
 518   if (data->info)
 519     return g_object_ref (data->info);
 520
 521   return NULL;
 522 }
 523
 524 #define __G_FILE_INPUT_STREAM_C__
 525 #include "gioaliasdef.c"
 526