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_set_pending (input_stream, error))
 132     return NULL;
 133
 134   info = NULL;
 135
 136   if (cancellable)
 137     g_push_current_cancellable (cancellable);
 138
 139   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 140   if (class->query_info)
 141     info = class->query_info (stream, attributes, cancellable, error);
 142   else
 143     g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 144                  _("Stream doesn't support query_info"));
 145
 146   if (cancellable)
 147     g_pop_current_cancellable (cancellable);
 148
 149   g_input_stream_clear_pending (input_stream);
 150
 151   return info;
 152 }
 153
 154 static void
 155 async_ready_callback_wrapper (GObject      *source_object,
 156                               GAsyncResult *res,
 157                               gpointer      user_data)
 158 {
 159   GFileInputStream *stream = G_FILE_INPUT_STREAM (source_object);
 160
 161   g_input_stream_clear_pending (G_INPUT_STREAM (stream));
 162   if (stream->priv->outstanding_callback)
 163     (*stream->priv->outstanding_callback) (source_object, res, user_data);
 164   g_object_unref (stream);
 165 }
 166
 167 /**
 168  * g_file_input_stream_query_info_async:
 169  * @stream: a #GFileInputStream.
 170  * @attributes: a file attribute query string.
 171  * @io_priority: the <link linkend="io-priority">I/O priority</link>
 172  *     of the request.
 173  * @cancellable: optional #GCancellable object, %NULL to ignore.
 174  * @callback: callback to call when the request is satisfied
 175  * @user_data: the data to pass to callback function
 176  *
 177  * Queries the stream information asynchronously. For the synchronous
 178  * version of this function, see g_file_input_stream_query_info().
 179  *
 180  * If @cancellable is not %NULL, then the operation can be cancelled by
 181  * triggering the cancellable object from another thread. If the operation
 182  * was cancelled, the error %G_IO_ERROR_CANCELLED will be set
 183  *
 184  **/
 185 void
 186 g_file_input_stream_query_info_async (GFileInputStream    *stream,
 187                                       char                *attributes,
 188                                       int                  io_priority,
 189                                       GCancellable        *cancellable,
 190                                       GAsyncReadyCallback  callback,
 191                                       gpointer             user_data)
 192 {
 193   GFileInputStreamClass *klass;
 194   GInputStream *input_stream;
 195   GError *error = NULL;
 196
 197   g_return_if_fail (G_IS_FILE_INPUT_STREAM (stream));
 198
 199   input_stream = G_INPUT_STREAM (stream);
 200
 201   if (!g_input_stream_set_pending (input_stream, &error))
 202     {
 203       g_simple_async_report_gerror_in_idle (G_OBJECT (stream),
 204                                             callback,
 205                                             user_data,
 206                                             error);
 207       g_error_free (error);
 208       return;
 209     }
 210
 211   klass = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 212
 213   stream->priv->outstanding_callback = callback;
 214   g_object_ref (stream);
 215   klass->query_info_async (stream, attributes, io_priority, cancellable,
 216                               async_ready_callback_wrapper, user_data);
 217 }
 218
 219 /**
 220  * g_file_input_stream_query_info_finish:
 221  * @stream: a #GFileInputStream.
 222  * @result: a #GAsyncResult.
 223  * @error: a #GError location to store the error occuring,
 224  *     or %NULL to ignore.
 225  *
 226  * Finishes an asynchronous info query operation.
 227  *
 228  * Returns: #GFileInfo.
 229  **/
 230 GFileInfo *
 231 g_file_input_stream_query_info_finish (GFileInputStream  *stream,
 232                                        GAsyncResult      *result,
 233                                        GError           **error)
 234 {
 235   GSimpleAsyncResult *simple;
 236   GFileInputStreamClass *class;
 237
 238   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), NULL);
 239   g_return_val_if_fail (G_IS_ASYNC_RESULT (result), NULL);
 240
 241   if (G_IS_SIMPLE_ASYNC_RESULT (result))
 242     {
 243       simple = G_SIMPLE_ASYNC_RESULT (result);
 244       if (g_simple_async_result_propagate_error (simple, error))
 245         return NULL;
 246     }
 247
 248   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 249   return class->query_info_finish (stream, result, error);
 250 }
 251
 252 /**
 253  * g_file_input_stream_tell:
 254  * @stream: a #GFileInputStream.
 255  *
 256  * Gets the current position in the stream.
 257  *
 258  * Returns: a #goffset with the position in the stream.
 259  **/
 260 goffset
 261 g_file_input_stream_tell (GFileInputStream *stream)
 262 {
 263   GFileInputStreamClass *class;
 264   goffset offset;
 265
 266   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), 0);
 267
 268   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 269
 270   offset = 0;
 271   if (class->tell)
 272     offset = class->tell (stream);
 273
 274   return offset;
 275 }
 276
 277 static goffset
 278 g_file_input_stream_seekable_tell (GSeekable *seekable)
 279 {
 280   return g_file_input_stream_tell (G_FILE_INPUT_STREAM (seekable));
 281 }
 282
 283 /**
 284  * g_file_input_stream_can_seek:
 285  * @stream: a #GFileInputStream.
 286  *
 287  * Checks if a file input stream can be seeked.
 288  *
 289  * Returns: %TRUE if stream can be seeked. %FALSE otherwise.
 290  **/
 291 gboolean
 292 g_file_input_stream_can_seek (GFileInputStream *stream)
 293 {
 294   GFileInputStreamClass *class;
 295   gboolean can_seek;
 296
 297   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), FALSE);
 298
 299   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 300
 301   can_seek = FALSE;
 302   if (class->seek)
 303     {
 304       can_seek = TRUE;
 305       if (class->can_seek)
 306         can_seek = class->can_seek (stream);
 307     }
 308
 309   return can_seek;
 310 }
 311
 312 static gboolean
 313 g_file_input_stream_seekable_can_seek (GSeekable *seekable)
 314 {
 315   return g_file_input_stream_can_seek (G_FILE_INPUT_STREAM (seekable));
 316 }
 317
 318 /**
 319  * g_file_input_stream_seek:
 320  * @stream: a #GFileInputStream.
 321  * @offset: a #goffset to seek.
 322  * @type: a #GSeekType.
 323  * @cancellable: optional #GCancellable object, %NULL to ignore.
 324  * @error: a #GError location to store the error occuring, or
 325  *     %NULL to ignore.
 326  *
 327  * Seeks in the file input stream.
 328  *
 329  * If @cancellable is not %NULL, then the operation can be cancelled by
 330  * triggering the cancellable object from another thread. If the operation
 331  * was cancelled, the error %G_IO_ERROR_CANCELLED will be set.
 332  *
 333  * Returns: %TRUE if the stream was successfully seeked to the position.
 334  * %FALSE on error.
 335  **/
 336 gboolean
 337 g_file_input_stream_seek (GFileInputStream  *stream,
 338                           goffset            offset,
 339                           GSeekType          type,
 340                           GCancellable      *cancellable,
 341                           GError           **error)
 342 {
 343   GFileInputStreamClass *class;
 344   GInputStream *input_stream;
 345   gboolean res;
 346
 347   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), FALSE);
 348
 349   input_stream = G_INPUT_STREAM (stream);
 350   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 351
 352   if (!class->seek)
 353     {
 354       g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 355                    _("Seek not supported on stream"));
 356       return FALSE;
 357     }
 358
 359   if (!g_input_stream_set_pending (input_stream, error))
 360     return FALSE;
 361
 362   if (cancellable)
 363     g_push_current_cancellable (cancellable);
 364
 365   res = class->seek (stream, offset, type, cancellable, error);
 366
 367   if (cancellable)
 368     g_pop_current_cancellable (cancellable);
 369
 370   g_input_stream_clear_pending (input_stream);
 371
 372   return res;
 373 }
 374
 375 static gboolean
 376 g_file_input_stream_seekable_seek (GSeekable     *seekable,
 377                                    goffset        offset,
 378                                    GSeekType      type,
 379                                    GCancellable  *cancellable,
 380                                    GError       **error)
 381 {
 382   return g_file_input_stream_seek (G_FILE_INPUT_STREAM (seekable),
 383                                    offset, type, cancellable, error);
 384 }
 385
 386 static gboolean
 387 g_file_input_stream_seekable_can_truncate (GSeekable *seekable)
 388 {
 389   return FALSE;
 390 }
 391
 392 static gboolean
 393 g_file_input_stream_seekable_truncate (GSeekable     *seekable,
 394                                        goffset        offset,
 395                                        GCancellable  *cancellable,
 396                                        GError       **error)
 397 {
 398   g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 399                _("Truncate not allowed on input stream"));
 400   return FALSE;
 401 }
 402
 403 /********************************************
 404  *   Default implementation of async ops    *
 405  ********************************************/
 406
 407 typedef struct {
 408   char *attributes;
 409   GFileInfo *info;
 410 } QueryInfoAsyncData;
 411
 412 static void
 413 query_info_data_free (QueryInfoAsyncData *data)
 414 {
 415   if (data->info)
 416     g_object_unref (data->info);
 417   g_free (data->attributes);
 418   g_free (data);
 419 }
 420
 421 static void
 422 query_info_async_thread (GSimpleAsyncResult *res,
 423                          GObject            *object,
 424                          GCancellable       *cancellable)
 425 {
 426   GFileInputStreamClass *class;
 427   GError *error = NULL;
 428   QueryInfoAsyncData *data;
 429   GFileInfo *info;
 430
 431   data = g_simple_async_result_get_op_res_gpointer (res);
 432
 433   info = NULL;
 434
 435   class = G_FILE_INPUT_STREAM_GET_CLASS (object);
 436   if (class->query_info)
 437     info = class->query_info (G_FILE_INPUT_STREAM (object), data->attributes, cancellable, &error);
 438   else
 439     g_set_error (&error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 440                  _("Stream doesn't support query_info"));
 441
 442   if (info == NULL)
 443     {
 444       g_simple_async_result_set_from_error (res, error);
 445       g_error_free (error);
 446     }
 447   else
 448     data->info = info;
 449 }
 450
 451 static void
 452 g_file_input_stream_real_query_info_async (GFileInputStream    *stream,
 453                                            char                *attributes,
 454                                            int                  io_priority,
 455                                            GCancellable        *cancellable,
 456                                            GAsyncReadyCallback  callback,
 457                                            gpointer             user_data)
 458 {
 459   GSimpleAsyncResult *res;
 460   QueryInfoAsyncData *data;
 461
 462   data = g_new0 (QueryInfoAsyncData, 1);
 463   data->attributes = g_strdup (attributes);
 464
 465   res = g_simple_async_result_new (G_OBJECT (stream), callback, user_data, g_file_input_stream_real_query_info_async);
 466   g_simple_async_result_set_op_res_gpointer (res, data, (GDestroyNotify)query_info_data_free);
 467
 468   g_simple_async_result_run_in_thread (res, query_info_async_thread, io_priority, cancellable);
 469   g_object_unref (res);
 470 }
 471
 472 static GFileInfo *
 473 g_file_input_stream_real_query_info_finish (GFileInputStream  *stream,
 474                                             GAsyncResult      *res,
 475                                             GError           **error)
 476 {
 477   GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (res);
 478   QueryInfoAsyncData *data;
 479
 480   g_assert (g_simple_async_result_get_source_tag (simple) == g_file_input_stream_real_query_info_async);
 481
 482   data = g_simple_async_result_get_op_res_gpointer (simple);
 483   if (data->info)
 484     return g_object_ref (data->info);
 485
 486   return NULL;
 487 }
 488
 489 #define __G_FILE_INPUT_STREAM_C__
 490 #include "gioaliasdef.c"
 491