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 static void       g_file_input_stream_seekable_iface_init    (GSeekableIface       *iface);
  32 static goffset    g_file_input_stream_seekable_tell          (GSeekable            *seekable);
  33 static gboolean   g_file_input_stream_seekable_can_seek      (GSeekable            *seekable);
  34 static gboolean   g_file_input_stream_seekable_seek          (GSeekable            *seekable,
  35                                                               goffset               offset,
  36                                                               GSeekType             type,
  37                                                               GCancellable         *cancellable,
  38                                                               GError              **error);
  39 static gboolean   g_file_input_stream_seekable_can_truncate  (GSeekable            *seekable);
  40 static gboolean   g_file_input_stream_seekable_truncate      (GSeekable            *seekable,
  41                                                               goffset               offset,
  42                                                               GCancellable         *cancellable,
  43                                                               GError              **error);
  44 static void       g_file_input_stream_real_query_info_async  (GFileInputStream     *stream,
  45                                                               char                 *attributes,
  46                                                               int                   io_priority,
  47                                                               GCancellable         *cancellable,
  48                                                               GAsyncReadyCallback   callback,
  49                                                               gpointer              user_data);
  50 static GFileInfo *g_file_input_stream_real_query_info_finish (GFileInputStream     *stream,
  51                                                               GAsyncResult         *result,
  52                                                               GError              **error);
  53
  54
  55 G_DEFINE_TYPE_WITH_CODE (GFileInputStream, g_file_input_stream, G_TYPE_INPUT_STREAM,
  56                          G_IMPLEMENT_INTERFACE (G_TYPE_SEEKABLE,
  57                                                 g_file_input_stream_seekable_iface_init))
  58
  59 struct _GFileInputStreamPrivate {
  60   GAsyncReadyCallback outstanding_callback;
  61 };
  62
  63 static void
  64 g_file_input_stream_class_init (GFileInputStreamClass *klass)
  65 {
  66   g_type_class_add_private (klass, sizeof (GFileInputStreamPrivate));
  67
  68   klass->query_info_async = g_file_input_stream_real_query_info_async;
  69   klass->query_info_finish = g_file_input_stream_real_query_info_finish;
  70 }
  71
  72 static void
  73 g_file_input_stream_seekable_iface_init (GSeekableIface *iface)
  74 {
  75   iface->tell = g_file_input_stream_seekable_tell;
  76   iface->can_seek = g_file_input_stream_seekable_can_seek;
  77   iface->seek = g_file_input_stream_seekable_seek;
  78   iface->can_truncate = g_file_input_stream_seekable_can_truncate;
  79   iface->truncate = g_file_input_stream_seekable_truncate;
  80 }
  81
  82 static void
  83 g_file_input_stream_init (GFileInputStream *stream)
  84 {
  85   stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (stream,
  86                                               G_TYPE_FILE_INPUT_STREAM,
  87                                               GFileInputStreamPrivate);
  88 }
  89
  90 /**
  91  * g_file_input_stream_query_info:
  92  * @stream:
  93  * @attributes:
  94  * @cancellable: optional #GCancellable object, %NULL to ignore.
  95  * @error: a #GError location to store the error occuring, or %NULL to
  96  * ignore.
  97  * Returns:
  98  **/
  99 GFileInfo *
 100 g_file_input_stream_query_info (GFileInputStream     *stream,
 101                                    char                 *attributes,
 102                                    GCancellable         *cancellable,
 103                                    GError              **error)
 104 {
 105   GFileInputStreamClass *class;
 106   GInputStream *input_stream;
 107   GFileInfo *info;
 108
 109   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), NULL);
 110
 111   input_stream = G_INPUT_STREAM (stream);
 112
 113   if (g_input_stream_is_closed (input_stream))
 114     {
 115       g_set_error (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
 116                    _("Stream is already closed"));
 117       return NULL;
 118     }
 119
 120   if (g_input_stream_has_pending (input_stream))
 121     {
 122       g_set_error (error, G_IO_ERROR, G_IO_ERROR_PENDING,
 123                    _("Stream has outstanding operation"));
 124       return NULL;
 125     }
 126
 127   info = NULL;
 128
 129   g_input_stream_set_pending (input_stream, TRUE);
 130
 131   if (cancellable)
 132     g_push_current_cancellable (cancellable);
 133
 134   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 135   if (class->query_info)
 136     info = class->query_info (stream, attributes, cancellable, error);
 137   else
 138     g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 139                  _("Stream doesn't support query_info"));
 140
 141   if (cancellable)
 142     g_pop_current_cancellable (cancellable);
 143
 144   g_input_stream_set_pending (input_stream, FALSE);
 145
 146   return info;
 147 }
 148
 149 static void
 150 async_ready_callback_wrapper (GObject *source_object,
 151                               GAsyncResult *res,
 152                               gpointer      user_data)
 153 {
 154   GFileInputStream *stream = G_FILE_INPUT_STREAM (source_object);
 155
 156   g_input_stream_set_pending (G_INPUT_STREAM (stream), FALSE);
 157   if (stream->priv->outstanding_callback)
 158     (*stream->priv->outstanding_callback) (source_object, res, user_data);
 159   g_object_unref (stream);
 160 }
 161
 162 /**
 163  * g_file_input_stream_query_info_async:
 164  * @stream:
 165  * @attributes:
 166  * @io_priority: the io priority of the request.
 167  * @cancellable: optional #GCancellable object, %NULL to ignore. @callback:
 168  * @user_data:
 169  *
 170  **/
 171 void
 172 g_file_input_stream_query_info_async (GFileInputStream     *stream,
 173                                          char                 *attributes,
 174                                          int                   io_priority,
 175                                          GCancellable         *cancellable,
 176                                          GAsyncReadyCallback   callback,
 177                                          gpointer              user_data)
 178 {
 179   GFileInputStreamClass *klass;
 180   GInputStream *input_stream;
 181
 182   g_return_if_fail (G_IS_FILE_INPUT_STREAM (stream));
 183
 184   input_stream = G_INPUT_STREAM (stream);
 185
 186   if (g_input_stream_is_closed (input_stream))
 187     {
 188       g_simple_async_report_error_in_idle (G_OBJECT (stream),
 189                                            callback,
 190                                            user_data,
 191                                            G_IO_ERROR, G_IO_ERROR_CLOSED,
 192                                            _("Stream is already closed"));
 193       return;
 194     }
 195
 196   if (g_input_stream_has_pending (input_stream))
 197     {
 198       g_simple_async_report_error_in_idle (G_OBJECT (stream),
 199                                            callback,
 200                                            user_data,
 201                                            G_IO_ERROR, G_IO_ERROR_PENDING,
 202                                            _("Stream has outstanding operation"));
 203       return;
 204     }
 205
 206   klass = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 207
 208   g_input_stream_set_pending (input_stream, TRUE);
 209   stream->priv->outstanding_callback = callback;
 210   g_object_ref (stream);
 211   klass->query_info_async (stream, attributes, io_priority, cancellable,
 212                               async_ready_callback_wrapper, user_data);
 213 }
 214
 215 /**
 216  * g_file_input_stream_query_info_finish:
 217  * @stream:
 218  * @result:
 219  * @error: a #GError location to store the error occuring, or %NULL to
 220  * ignore.
 221  * Returns: #GFileInfo.
 222  **/
 223 GFileInfo *
 224 g_file_input_stream_query_info_finish (GFileInputStream     *stream,
 225                                           GAsyncResult         *result,
 226                                           GError              **error)
 227 {
 228   GSimpleAsyncResult *simple;
 229   GFileInputStreamClass *class;
 230
 231   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), NULL);
 232   g_return_val_if_fail (G_IS_ASYNC_RESULT (result), NULL);
 233
 234   if (G_IS_SIMPLE_ASYNC_RESULT (result))
 235     {
 236       simple = G_SIMPLE_ASYNC_RESULT (result);
 237       if (g_simple_async_result_propagate_error (simple, error))
 238         return NULL;
 239     }
 240
 241   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 242   return class->query_info_finish (stream, result, error);
 243 }
 244
 245 /**
 246  * g_file_input_stream_tell:
 247  * @stream:
 248  *
 249  * Returns:
 250  **/
 251 goffset
 252 g_file_input_stream_tell (GFileInputStream  *stream)
 253 {
 254   GFileInputStreamClass *class;
 255   goffset offset;
 256
 257   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), 0);
 258
 259   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 260
 261   offset = 0;
 262   if (class->tell)
 263     offset = class->tell (stream);
 264
 265   return offset;
 266 }
 267
 268 static goffset
 269 g_file_input_stream_seekable_tell (GSeekable *seekable)
 270 {
 271   return g_file_input_stream_tell (G_FILE_INPUT_STREAM (seekable));
 272 }
 273
 274 /**
 275  * g_file_input_stream_can_seek:
 276  * @stream:
 277  *
 278  * Returns: %TRUE if stream can be seeked. %FALSE otherwise.
 279  **/
 280 gboolean
 281 g_file_input_stream_can_seek (GFileInputStream  *stream)
 282 {
 283   GFileInputStreamClass *class;
 284   gboolean can_seek;
 285
 286   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), FALSE);
 287
 288   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 289
 290   can_seek = FALSE;
 291   if (class->seek)
 292     {
 293       can_seek = TRUE;
 294       if (class->can_seek)
 295         can_seek = class->can_seek (stream);
 296     }
 297
 298   return can_seek;
 299 }
 300
 301 static gboolean
 302 g_file_input_stream_seekable_can_seek (GSeekable *seekable)
 303 {
 304   return g_file_input_stream_can_seek (G_FILE_INPUT_STREAM (seekable));
 305 }
 306
 307 /**
 308  * g_file_input_stream_seek:
 309  * @stream:
 310  * @offset:
 311  * @type:
 312  * @cancellable: optional #GCancellable object, %NULL to ignore.
 313  * @error: a #GError location to store the error occuring, or %NULL to
 314  * ignore.
 315  * Returns:
 316  **/
 317 gboolean
 318 g_file_input_stream_seek (GFileInputStream  *stream,
 319                           goffset            offset,
 320                           GSeekType          type,
 321                           GCancellable      *cancellable,
 322                           GError           **error)
 323 {
 324   GFileInputStreamClass *class;
 325   GInputStream *input_stream;
 326   gboolean res;
 327
 328   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), FALSE);
 329
 330   input_stream = G_INPUT_STREAM (stream);
 331   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 332
 333   if (g_input_stream_is_closed (input_stream))
 334     {
 335       g_set_error (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
 336                    _("Stream is already closed"));
 337       return FALSE;
 338     }
 339
 340   if (g_input_stream_has_pending (input_stream))
 341     {
 342       g_set_error (error, G_IO_ERROR, G_IO_ERROR_PENDING,
 343                    _("Stream has outstanding operation"));
 344       return FALSE;
 345     }
 346
 347   if (!class->seek)
 348     {
 349       g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 350                    _("Seek not supported on stream"));
 351       return FALSE;
 352     }
 353
 354   g_input_stream_set_pending (input_stream, TRUE);
 355
 356   if (cancellable)
 357     g_push_current_cancellable (cancellable);
 358
 359   res = class->seek (stream, offset, type, cancellable, error);
 360
 361   if (cancellable)
 362     g_pop_current_cancellable (cancellable);
 363
 364   g_input_stream_set_pending (input_stream, FALSE);
 365
 366   return res;
 367 }
 368
 369 static gboolean
 370 g_file_input_stream_seekable_seek (GSeekable  *seekable,
 371                                    goffset     offset,
 372                                    GSeekType   type,
 373                                    GCancellable  *cancellable,
 374                                    GError    **error)
 375 {
 376   return g_file_input_stream_seek (G_FILE_INPUT_STREAM (seekable),
 377                                    offset, type, cancellable, error);
 378 }
 379
 380 static gboolean
 381 g_file_input_stream_seekable_can_truncate (GSeekable  *seekable)
 382 {
 383   return FALSE;
 384 }
 385
 386 static gboolean
 387 g_file_input_stream_seekable_truncate (GSeekable  *seekable,
 388                                        goffset     offset,
 389                                        GCancellable  *cancellable,
 390                                        GError    **error)
 391 {
 392   g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 393                _("Truncate not allowed on input stream"));
 394   return FALSE;
 395 }
 396
 397 /********************************************
 398  *   Default implementation of async ops    *
 399  ********************************************/
 400
 401 typedef struct {
 402   char *attributes;
 403   GFileInfo *info;
 404 } QueryInfoAsyncData;
 405
 406 static void
 407 query_info_data_free (QueryInfoAsyncData *data)
 408 {
 409   if (data->info)
 410     g_object_unref (data->info);
 411   g_free (data->attributes);
 412   g_free (data);
 413 }
 414
 415 static void
 416 query_info_async_thread (GSimpleAsyncResult *res,
 417                        GObject *object,
 418                        GCancellable *cancellable)
 419 {
 420   GFileInputStreamClass *class;
 421   GError *error = NULL;
 422   QueryInfoAsyncData *data;
 423   GFileInfo *info;
 424
 425   data = g_simple_async_result_get_op_res_gpointer (res);
 426
 427   info = NULL;
 428
 429   class = G_FILE_INPUT_STREAM_GET_CLASS (object);
 430   if (class->query_info)
 431     info = class->query_info (G_FILE_INPUT_STREAM (object), data->attributes, cancellable, &error);
 432   else
 433     g_set_error (&error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 434                  _("Stream doesn't support query_info"));
 435
 436   if (info == NULL)
 437     {
 438       g_simple_async_result_set_from_error (res, error);
 439       g_error_free (error);
 440     }
 441   else
 442     data->info = info;
 443 }
 444
 445 static void
 446 g_file_input_stream_real_query_info_async (GFileInputStream     *stream,
 447                                               char                 *attributes,
 448                                               int                   io_priority,
 449                                               GCancellable         *cancellable,
 450                                               GAsyncReadyCallback   callback,
 451                                               gpointer              user_data)
 452 {
 453   GSimpleAsyncResult *res;
 454   QueryInfoAsyncData *data;
 455
 456   data = g_new0 (QueryInfoAsyncData, 1);
 457   data->attributes = g_strdup (attributes);
 458
 459   res = g_simple_async_result_new (G_OBJECT (stream), callback, user_data, g_file_input_stream_real_query_info_async);
 460   g_simple_async_result_set_op_res_gpointer (res, data, (GDestroyNotify)query_info_data_free);
 461
 462   g_simple_async_result_run_in_thread (res, query_info_async_thread, io_priority, cancellable);
 463   g_object_unref (res);
 464 }
 465
 466 static GFileInfo *
 467 g_file_input_stream_real_query_info_finish (GFileInputStream     *stream,
 468                                                GAsyncResult         *res,
 469                                                GError              **error)
 470 {
 471   GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (res);
 472   QueryInfoAsyncData *data;
 473
 474   g_assert (g_simple_async_result_get_source_tag (simple) == g_file_input_stream_real_query_info_async);
 475
 476   data = g_simple_async_result_get_op_res_gpointer (simple);
 477   if (data->info)
 478     return g_object_ref (data->info);
 479
 480   return NULL;
 481 }