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 <link linkend="io-priority">I/O priority</link>
 185  *     of the request.
 186  * @cancellable: optional #GCancellable object, %NULL to ignore.
 187  * @callback: callback to call when the request is satisfied
 188  * @user_data: the data to pass to callback function
 189  *
 190  * Queries the stream information asynchronously. For the synchronous
 191  * version of this function, see g_file_input_stream_query_info().
 192  *
 193  * If @cancellable is not %NULL, then the operation can be cancelled by
 194  * triggering the cancellable object from another thread. If the operation
 195  * was cancelled, the error %G_IO_ERROR_CANCELLED will be set
 196  *
 197  **/
 198 void
 199 g_file_input_stream_query_info_async (GFileInputStream    *stream,
 200                                       char                *attributes,
 201                                       int                  io_priority,
 202                                       GCancellable        *cancellable,
 203                                       GAsyncReadyCallback  callback,
 204                                       gpointer             user_data)
 205 {
 206   GFileInputStreamClass *klass;
 207   GInputStream *input_stream;
 208
 209   g_return_if_fail (G_IS_FILE_INPUT_STREAM (stream));
 210
 211   input_stream = G_INPUT_STREAM (stream);
 212
 213   if (g_input_stream_is_closed (input_stream))
 214     {
 215       g_simple_async_report_error_in_idle (G_OBJECT (stream),
 216                                            callback,
 217                                            user_data,
 218                                            G_IO_ERROR, G_IO_ERROR_CLOSED,
 219                                            _("Stream is already closed"));
 220       return;
 221     }
 222
 223   if (g_input_stream_has_pending (input_stream))
 224     {
 225       g_simple_async_report_error_in_idle (G_OBJECT (stream),
 226                                            callback,
 227                                            user_data,
 228                                            G_IO_ERROR, G_IO_ERROR_PENDING,
 229                                            _("Stream has outstanding operation"));
 230       return;
 231     }
 232
 233   klass = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 234
 235   g_input_stream_set_pending (input_stream, TRUE);
 236   stream->priv->outstanding_callback = callback;
 237   g_object_ref (stream);
 238   klass->query_info_async (stream, attributes, io_priority, cancellable,
 239                               async_ready_callback_wrapper, user_data);
 240 }
 241
 242 /**
 243  * g_file_input_stream_query_info_finish:
 244  * @stream: a #GFileInputStream.
 245  * @result: a #GAsyncResult.
 246  * @error: a #GError location to store the error occuring,
 247  *     or %NULL to ignore.
 248  *
 249  * Finishes an asynchronous info query operation.
 250  *
 251  * Returns: #GFileInfo.
 252  **/
 253 GFileInfo *
 254 g_file_input_stream_query_info_finish (GFileInputStream  *stream,
 255                                        GAsyncResult      *result,
 256                                        GError           **error)
 257 {
 258   GSimpleAsyncResult *simple;
 259   GFileInputStreamClass *class;
 260
 261   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), NULL);
 262   g_return_val_if_fail (G_IS_ASYNC_RESULT (result), NULL);
 263
 264   if (G_IS_SIMPLE_ASYNC_RESULT (result))
 265     {
 266       simple = G_SIMPLE_ASYNC_RESULT (result);
 267       if (g_simple_async_result_propagate_error (simple, error))
 268         return NULL;
 269     }
 270
 271   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 272   return class->query_info_finish (stream, result, error);
 273 }
 274
 275 /**
 276  * g_file_input_stream_tell:
 277  * @stream: a #GFileInputStream.
 278  *
 279  * Gets the current position in the stream.
 280  *
 281  * Returns: a #goffset with the position in the stream.
 282  **/
 283 goffset
 284 g_file_input_stream_tell (GFileInputStream *stream)
 285 {
 286   GFileInputStreamClass *class;
 287   goffset offset;
 288
 289   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), 0);
 290
 291   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 292
 293   offset = 0;
 294   if (class->tell)
 295     offset = class->tell (stream);
 296
 297   return offset;
 298 }
 299
 300 static goffset
 301 g_file_input_stream_seekable_tell (GSeekable *seekable)
 302 {
 303   return g_file_input_stream_tell (G_FILE_INPUT_STREAM (seekable));
 304 }
 305
 306 /**
 307  * g_file_input_stream_can_seek:
 308  * @stream: a #GFileInputStream.
 309  *
 310  * Checks if a file input stream can be seeked.
 311  *
 312  * Returns: %TRUE if stream can be seeked. %FALSE otherwise.
 313  **/
 314 gboolean
 315 g_file_input_stream_can_seek (GFileInputStream *stream)
 316 {
 317   GFileInputStreamClass *class;
 318   gboolean can_seek;
 319
 320   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), FALSE);
 321
 322   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 323
 324   can_seek = FALSE;
 325   if (class->seek)
 326     {
 327       can_seek = TRUE;
 328       if (class->can_seek)
 329         can_seek = class->can_seek (stream);
 330     }
 331
 332   return can_seek;
 333 }
 334
 335 static gboolean
 336 g_file_input_stream_seekable_can_seek (GSeekable *seekable)
 337 {
 338   return g_file_input_stream_can_seek (G_FILE_INPUT_STREAM (seekable));
 339 }
 340
 341 /**
 342  * g_file_input_stream_seek:
 343  * @stream: a #GFileInputStream.
 344  * @offset: a #goffset to seek.
 345  * @type: a #GSeekType.
 346  * @cancellable: optional #GCancellable object, %NULL to ignore.
 347  * @error: a #GError location to store the error occuring, or
 348  *     %NULL to ignore.
 349  *
 350  * Seeks in the file input stream.
 351  *
 352  * If @cancellable is not %NULL, then the operation can be cancelled by
 353  * triggering the cancellable object from another thread. If the operation
 354  * was cancelled, the error %G_IO_ERROR_CANCELLED will be set.
 355  *
 356  * Returns: %TRUE if the stream was successfully seeked to the position.
 357  * %FALSE on error.
 358  **/
 359 gboolean
 360 g_file_input_stream_seek (GFileInputStream  *stream,
 361                           goffset            offset,
 362                           GSeekType          type,
 363                           GCancellable      *cancellable,
 364                           GError           **error)
 365 {
 366   GFileInputStreamClass *class;
 367   GInputStream *input_stream;
 368   gboolean res;
 369
 370   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), FALSE);
 371
 372   input_stream = G_INPUT_STREAM (stream);
 373   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 374
 375   if (g_input_stream_is_closed (input_stream))
 376     {
 377       g_set_error (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
 378                    _("Stream is already closed"));
 379       return FALSE;
 380     }
 381
 382   if (g_input_stream_has_pending (input_stream))
 383     {
 384       g_set_error (error, G_IO_ERROR, G_IO_ERROR_PENDING,
 385                    _("Stream has outstanding operation"));
 386       return FALSE;
 387     }
 388
 389   if (!class->seek)
 390     {
 391       g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 392                    _("Seek not supported on stream"));
 393       return FALSE;
 394     }
 395
 396   g_input_stream_set_pending (input_stream, TRUE);
 397
 398   if (cancellable)
 399     g_push_current_cancellable (cancellable);
 400
 401   res = class->seek (stream, offset, type, cancellable, error);
 402
 403   if (cancellable)
 404     g_pop_current_cancellable (cancellable);
 405
 406   g_input_stream_set_pending (input_stream, FALSE);
 407
 408   return res;
 409 }
 410
 411 static gboolean
 412 g_file_input_stream_seekable_seek (GSeekable     *seekable,
 413                                    goffset        offset,
 414                                    GSeekType      type,
 415                                    GCancellable  *cancellable,
 416                                    GError       **error)
 417 {
 418   return g_file_input_stream_seek (G_FILE_INPUT_STREAM (seekable),
 419                                    offset, type, cancellable, error);
 420 }
 421
 422 static gboolean
 423 g_file_input_stream_seekable_can_truncate (GSeekable *seekable)
 424 {
 425   return FALSE;
 426 }
 427
 428 static gboolean
 429 g_file_input_stream_seekable_truncate (GSeekable     *seekable,
 430                                        goffset        offset,
 431                                        GCancellable  *cancellable,
 432                                        GError       **error)
 433 {
 434   g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 435                _("Truncate not allowed on input stream"));
 436   return FALSE;
 437 }
 438
 439 /********************************************
 440  *   Default implementation of async ops    *
 441  ********************************************/
 442
 443 typedef struct {
 444   char *attributes;
 445   GFileInfo *info;
 446 } QueryInfoAsyncData;
 447
 448 static void
 449 query_info_data_free (QueryInfoAsyncData *data)
 450 {
 451   if (data->info)
 452     g_object_unref (data->info);
 453   g_free (data->attributes);
 454   g_free (data);
 455 }
 456
 457 static void
 458 query_info_async_thread (GSimpleAsyncResult *res,
 459                          GObject            *object,
 460                          GCancellable       *cancellable)
 461 {
 462   GFileInputStreamClass *class;
 463   GError *error = NULL;
 464   QueryInfoAsyncData *data;
 465   GFileInfo *info;
 466
 467   data = g_simple_async_result_get_op_res_gpointer (res);
 468
 469   info = NULL;
 470
 471   class = G_FILE_INPUT_STREAM_GET_CLASS (object);
 472   if (class->query_info)
 473     info = class->query_info (G_FILE_INPUT_STREAM (object), data->attributes, cancellable, &error);
 474   else
 475     g_set_error (&error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 476                  _("Stream doesn't support query_info"));
 477
 478   if (info == NULL)
 479     {
 480       g_simple_async_result_set_from_error (res, error);
 481       g_error_free (error);
 482     }
 483   else
 484     data->info = info;
 485 }
 486
 487 static void
 488 g_file_input_stream_real_query_info_async (GFileInputStream    *stream,
 489                                            char                *attributes,
 490                                            int                  io_priority,
 491                                            GCancellable        *cancellable,
 492                                            GAsyncReadyCallback  callback,
 493                                            gpointer             user_data)
 494 {
 495   GSimpleAsyncResult *res;
 496   QueryInfoAsyncData *data;
 497
 498   data = g_new0 (QueryInfoAsyncData, 1);
 499   data->attributes = g_strdup (attributes);
 500
 501   res = g_simple_async_result_new (G_OBJECT (stream), callback, user_data, g_file_input_stream_real_query_info_async);
 502   g_simple_async_result_set_op_res_gpointer (res, data, (GDestroyNotify)query_info_data_free);
 503
 504   g_simple_async_result_run_in_thread (res, query_info_async_thread, io_priority, cancellable);
 505   g_object_unref (res);
 506 }
 507
 508 static GFileInfo *
 509 g_file_input_stream_real_query_info_finish (GFileInputStream  *stream,
 510                                             GAsyncResult      *res,
 511                                             GError           **error)
 512 {
 513   GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (res);
 514   QueryInfoAsyncData *data;
 515
 516   g_assert (g_simple_async_result_get_source_tag (simple) == g_file_input_stream_real_query_info_async);
 517
 518   data = g_simple_async_result_get_op_res_gpointer (simple);
 519   if (data->info)
 520     return g_object_ref (data->info);
 521
 522   return NULL;
 523 }
 524
 525 #define __G_FILE_INPUT_STREAM_C__
 526 #include "gioaliasdef.c"
 527