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  * @include: gio.h
  37  * @see_also: #GInputStream, #GDataInputStream, #GSeekable
  38  *
  39  **/
  40
  41 static void       g_file_input_stream_seekable_iface_init    (GSeekableIface       *iface);
  42 static goffset    g_file_input_stream_seekable_tell          (GSeekable            *seekable);
  43 static gboolean   g_file_input_stream_seekable_can_seek      (GSeekable            *seekable);
  44 static gboolean   g_file_input_stream_seekable_seek          (GSeekable            *seekable,
  45                                                               goffset               offset,
  46                                                               GSeekType             type,
  47                                                               GCancellable         *cancellable,
  48                                                               GError              **error);
  49 static gboolean   g_file_input_stream_seekable_can_truncate  (GSeekable            *seekable);
  50 static gboolean   g_file_input_stream_seekable_truncate      (GSeekable            *seekable,
  51                                                               goffset               offset,
  52                                                               GCancellable         *cancellable,
  53                                                               GError              **error);
  54 static void       g_file_input_stream_real_query_info_async  (GFileInputStream     *stream,
  55                                                               char                 *attributes,
  56                                                               int                   io_priority,
  57                                                               GCancellable         *cancellable,
  58                                                               GAsyncReadyCallback   callback,
  59                                                               gpointer              user_data);
  60 static GFileInfo *g_file_input_stream_real_query_info_finish (GFileInputStream     *stream,
  61                                                               GAsyncResult         *result,
  62                                                               GError              **error);
  63
  64
  65 G_DEFINE_TYPE_WITH_CODE (GFileInputStream, g_file_input_stream, G_TYPE_INPUT_STREAM,
  66                          G_IMPLEMENT_INTERFACE (G_TYPE_SEEKABLE,
  67                                                 g_file_input_stream_seekable_iface_init))
  68
  69 struct _GFileInputStreamPrivate {
  70   GAsyncReadyCallback outstanding_callback;
  71 };
  72
  73 static void
  74 g_file_input_stream_class_init (GFileInputStreamClass *klass)
  75 {
  76   g_type_class_add_private (klass, sizeof (GFileInputStreamPrivate));
  77
  78   klass->query_info_async = g_file_input_stream_real_query_info_async;
  79   klass->query_info_finish = g_file_input_stream_real_query_info_finish;
  80 }
  81
  82 static void
  83 g_file_input_stream_seekable_iface_init (GSeekableIface *iface)
  84 {
  85   iface->tell = g_file_input_stream_seekable_tell;
  86   iface->can_seek = g_file_input_stream_seekable_can_seek;
  87   iface->seek = g_file_input_stream_seekable_seek;
  88   iface->can_truncate = g_file_input_stream_seekable_can_truncate;
  89   iface->truncate_fn = g_file_input_stream_seekable_truncate;
  90 }
  91
  92 static void
  93 g_file_input_stream_init (GFileInputStream *stream)
  94 {
  95   stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (stream,
  96                                               G_TYPE_FILE_INPUT_STREAM,
  97                                               GFileInputStreamPrivate);
  98 }
  99
 100 /**
 101  * g_file_input_stream_query_info:
 102  * @stream: a #GFileInputStream.
 103  * @attributes: a file attribute query string.
 104  * @cancellable: optional #GCancellable object, %NULL to ignore.
 105  * @error: a #GError location to store the error occuring, or %NULL to
 106  * ignore.
 107  *
 108  * Queries a file input stream the given @attributes.his function blocks
 109  * while querying the stream. For the asynchronous (non-blocking) version
 110  * of this function, see g_file_input_stream_query_info_async(). While the
 111  * stream is blocked, the stream will set the pending flag internally, and
 112  * any other operations on the stream will fail with %G_IO_ERROR_PENDING.
 113  *
 114  * Returns: a #GFileInfo, or %NULL on error.
 115  **/
 116 GFileInfo *
 117 g_file_input_stream_query_info (GFileInputStream  *stream,
 118                                 char              *attributes,
 119                                 GCancellable      *cancellable,
 120                                 GError           **error)
 121 {
 122   GFileInputStreamClass *class;
 123   GInputStream *input_stream;
 124   GFileInfo *info;
 125
 126   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), NULL);
 127
 128   input_stream = G_INPUT_STREAM (stream);
 129
 130   if (!g_input_stream_set_pending (input_stream, error))
 131     return NULL;
 132
 133   info = NULL;
 134
 135   if (cancellable)
 136     g_cancellable_push_current (cancellable);
 137
 138   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 139   if (class->query_info)
 140     info = class->query_info (stream, attributes, cancellable, error);
 141   else
 142     g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 143                  _("Stream doesn't support query_info"));
 144
 145   if (cancellable)
 146     g_cancellable_pop_current (cancellable);
 147
 148   g_input_stream_clear_pending (input_stream);
 149
 150   return info;
 151 }
 152
 153 static void
 154 async_ready_callback_wrapper (GObject      *source_object,
 155                               GAsyncResult *res,
 156                               gpointer      user_data)
 157 {
 158   GFileInputStream *stream = G_FILE_INPUT_STREAM (source_object);
 159
 160   g_input_stream_clear_pending (G_INPUT_STREAM (stream));
 161   if (stream->priv->outstanding_callback)
 162     (*stream->priv->outstanding_callback) (source_object, res, user_data);
 163   g_object_unref (stream);
 164 }
 165
 166 /**
 167  * g_file_input_stream_query_info_async:
 168  * @stream: a #GFileInputStream.
 169  * @attributes: a file attribute query string.
 170  * @io_priority: the <link linkend="io-priority">I/O priority</link>
 171  *     of the request.
 172  * @cancellable: optional #GCancellable object, %NULL to ignore.
 173  * @callback: callback to call when the request is satisfied
 174  * @user_data: the data to pass to callback function
 175  *
 176  * Queries the stream information asynchronously. For the synchronous
 177  * version of this function, see g_file_input_stream_query_info().
 178  *
 179  * If @cancellable is not %NULL, then the operation can be cancelled by
 180  * triggering the cancellable object from another thread. If the operation
 181  * was cancelled, the error %G_IO_ERROR_CANCELLED will be set
 182  *
 183  **/
 184 void
 185 g_file_input_stream_query_info_async (GFileInputStream    *stream,
 186                                       char                *attributes,
 187                                       int                  io_priority,
 188                                       GCancellable        *cancellable,
 189                                       GAsyncReadyCallback  callback,
 190                                       gpointer             user_data)
 191 {
 192   GFileInputStreamClass *klass;
 193   GInputStream *input_stream;
 194   GError *error = NULL;
 195
 196   g_return_if_fail (G_IS_FILE_INPUT_STREAM (stream));
 197
 198   input_stream = G_INPUT_STREAM (stream);
 199
 200   if (!g_input_stream_set_pending (input_stream, &error))
 201     {
 202       g_simple_async_report_gerror_in_idle (G_OBJECT (stream),
 203                                             callback,
 204                                             user_data,
 205                                             error);
 206       g_error_free (error);
 207       return;
 208     }
 209
 210   klass = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 211
 212   stream->priv->outstanding_callback = callback;
 213   g_object_ref (stream);
 214   klass->query_info_async (stream, attributes, io_priority, cancellable,
 215                               async_ready_callback_wrapper, user_data);
 216 }
 217
 218 /**
 219  * g_file_input_stream_query_info_finish:
 220  * @stream: a #GFileInputStream.
 221  * @result: a #GAsyncResult.
 222  * @error: a #GError location to store the error occuring,
 223  *     or %NULL to ignore.
 224  *
 225  * Finishes an asynchronous info query operation.
 226  *
 227  * Returns: #GFileInfo.
 228  **/
 229 GFileInfo *
 230 g_file_input_stream_query_info_finish (GFileInputStream  *stream,
 231                                        GAsyncResult      *result,
 232                                        GError           **error)
 233 {
 234   GSimpleAsyncResult *simple;
 235   GFileInputStreamClass *class;
 236
 237   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), NULL);
 238   g_return_val_if_fail (G_IS_ASYNC_RESULT (result), NULL);
 239
 240   if (G_IS_SIMPLE_ASYNC_RESULT (result))
 241     {
 242       simple = G_SIMPLE_ASYNC_RESULT (result);
 243       if (g_simple_async_result_propagate_error (simple, error))
 244         return NULL;
 245     }
 246
 247   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 248   return class->query_info_finish (stream, result, error);
 249 }
 250
 251 /**
 252  * g_file_input_stream_tell:
 253  * @stream: a #GFileInputStream.
 254  *
 255  * Gets the current position in the stream.
 256  *
 257  * Returns: a #goffset with the position in the stream.
 258  **/
 259 goffset
 260 g_file_input_stream_tell (GFileInputStream *stream)
 261 {
 262   GFileInputStreamClass *class;
 263   goffset offset;
 264
 265   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), 0);
 266
 267   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 268
 269   offset = 0;
 270   if (class->tell)
 271     offset = class->tell (stream);
 272
 273   return offset;
 274 }
 275
 276 static goffset
 277 g_file_input_stream_seekable_tell (GSeekable *seekable)
 278 {
 279   return g_file_input_stream_tell (G_FILE_INPUT_STREAM (seekable));
 280 }
 281
 282 /**
 283  * g_file_input_stream_can_seek:
 284  * @stream: a #GFileInputStream.
 285  *
 286  * Checks if a file input stream can be seeked.
 287  *
 288  * Returns: %TRUE if stream can be seeked. %FALSE otherwise.
 289  **/
 290 gboolean
 291 g_file_input_stream_can_seek (GFileInputStream *stream)
 292 {
 293   GFileInputStreamClass *class;
 294   gboolean can_seek;
 295
 296   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), FALSE);
 297
 298   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 299
 300   can_seek = FALSE;
 301   if (class->seek)
 302     {
 303       can_seek = TRUE;
 304       if (class->can_seek)
 305         can_seek = class->can_seek (stream);
 306     }
 307
 308   return can_seek;
 309 }
 310
 311 static gboolean
 312 g_file_input_stream_seekable_can_seek (GSeekable *seekable)
 313 {
 314   return g_file_input_stream_can_seek (G_FILE_INPUT_STREAM (seekable));
 315 }
 316
 317 /**
 318  * g_file_input_stream_seek:
 319  * @stream: a #GFileInputStream.
 320  * @offset: a #goffset to seek.
 321  * @type: a #GSeekType.
 322  * @cancellable: optional #GCancellable object, %NULL to ignore.
 323  * @error: a #GError location to store the error occuring, or
 324  *     %NULL to ignore.
 325  *
 326  * Seeks in the file input stream.
 327  *
 328  * If @cancellable is not %NULL, then the operation can be cancelled by
 329  * triggering the cancellable object from another thread. If the operation
 330  * was cancelled, the error %G_IO_ERROR_CANCELLED will be set.
 331  *
 332  * Returns: %TRUE if the stream was successfully seeked to the position.
 333  * %FALSE on error.
 334  **/
 335 gboolean
 336 g_file_input_stream_seek (GFileInputStream  *stream,
 337                           goffset            offset,
 338                           GSeekType          type,
 339                           GCancellable      *cancellable,
 340                           GError           **error)
 341 {
 342   GFileInputStreamClass *class;
 343   GInputStream *input_stream;
 344   gboolean res;
 345
 346   g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), FALSE);
 347
 348   input_stream = G_INPUT_STREAM (stream);
 349   class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
 350
 351   if (!class->seek)
 352     {
 353       g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 354                    _("Seek not supported on stream"));
 355       return FALSE;
 356     }
 357
 358   if (!g_input_stream_set_pending (input_stream, error))
 359     return FALSE;
 360
 361   if (cancellable)
 362     g_cancellable_push_current (cancellable);
 363
 364   res = class->seek (stream, offset, type, cancellable, error);
 365
 366   if (cancellable)
 367     g_cancellable_pop_current (cancellable);
 368
 369   g_input_stream_clear_pending (input_stream);
 370
 371   return res;
 372 }
 373
 374 static gboolean
 375 g_file_input_stream_seekable_seek (GSeekable     *seekable,
 376                                    goffset        offset,
 377                                    GSeekType      type,
 378                                    GCancellable  *cancellable,
 379                                    GError       **error)
 380 {
 381   return g_file_input_stream_seek (G_FILE_INPUT_STREAM (seekable),
 382                                    offset, type, cancellable, error);
 383 }
 384
 385 static gboolean
 386 g_file_input_stream_seekable_can_truncate (GSeekable *seekable)
 387 {
 388   return FALSE;
 389 }
 390
 391 static gboolean
 392 g_file_input_stream_seekable_truncate (GSeekable     *seekable,
 393                                        goffset        offset,
 394                                        GCancellable  *cancellable,
 395                                        GError       **error)
 396 {
 397   g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 398                _("Truncate not allowed on input stream"));
 399   return FALSE;
 400 }
 401
 402 /********************************************
 403  *   Default implementation of async ops    *
 404  ********************************************/
 405
 406 typedef struct {
 407   char *attributes;
 408   GFileInfo *info;
 409 } QueryInfoAsyncData;
 410
 411 static void
 412 query_info_data_free (QueryInfoAsyncData *data)
 413 {
 414   if (data->info)
 415     g_object_unref (data->info);
 416   g_free (data->attributes);
 417   g_free (data);
 418 }
 419
 420 static void
 421 query_info_async_thread (GSimpleAsyncResult *res,
 422                          GObject            *object,
 423                          GCancellable       *cancellable)
 424 {
 425   GFileInputStreamClass *class;
 426   GError *error = NULL;
 427   QueryInfoAsyncData *data;
 428   GFileInfo *info;
 429
 430   data = g_simple_async_result_get_op_res_gpointer (res);
 431
 432   info = NULL;
 433
 434   class = G_FILE_INPUT_STREAM_GET_CLASS (object);
 435   if (class->query_info)
 436     info = class->query_info (G_FILE_INPUT_STREAM (object), data->attributes, cancellable, &error);
 437   else
 438     g_set_error (&error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 439                  _("Stream doesn't support query_info"));
 440
 441   if (info == NULL)
 442     {
 443       g_simple_async_result_set_from_error (res, error);
 444       g_error_free (error);
 445     }
 446   else
 447     data->info = info;
 448 }
 449
 450 static void
 451 g_file_input_stream_real_query_info_async (GFileInputStream    *stream,
 452                                            char                *attributes,
 453                                            int                  io_priority,
 454                                            GCancellable        *cancellable,
 455                                            GAsyncReadyCallback  callback,
 456                                            gpointer             user_data)
 457 {
 458   GSimpleAsyncResult *res;
 459   QueryInfoAsyncData *data;
 460
 461   data = g_new0 (QueryInfoAsyncData, 1);
 462   data->attributes = g_strdup (attributes);
 463
 464   res = g_simple_async_result_new (G_OBJECT (stream), callback, user_data, g_file_input_stream_real_query_info_async);
 465   g_simple_async_result_set_op_res_gpointer (res, data, (GDestroyNotify)query_info_data_free);
 466
 467   g_simple_async_result_run_in_thread (res, query_info_async_thread, io_priority, cancellable);
 468   g_object_unref (res);
 469 }
 470
 471 static GFileInfo *
 472 g_file_input_stream_real_query_info_finish (GFileInputStream  *stream,
 473                                             GAsyncResult      *res,
 474                                             GError           **error)
 475 {
 476   GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (res);
 477   QueryInfoAsyncData *data;
 478
 479   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_file_input_stream_real_query_info_async);
 480
 481   data = g_simple_async_result_get_op_res_gpointer (simple);
 482   if (data->info)
 483     return g_object_ref (data->info);
 484
 485   return NULL;
 486 }
 487
 488 #define __G_FILE_INPUT_STREAM_C__
 489 #include "gioaliasdef.c"
 490