gio/goutputstream.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 #include "goutputstream.h"
  25 #include "gcancellable.h"
  26 #include "gasyncresult.h"
  27 #include "gsimpleasyncresult.h"
  28 #include "ginputstream.h"
  29 #include "gioerror.h"
  30 #include "glibintl.h"
  31
  32
  33 /**
  34  * SECTION:goutputstream
  35  * @short_description: Base class for implementing streaming output
  36  * @include: gio/gio.h
  37  *
  38  * GOutputStream has functions to write to a stream (g_output_stream_write()),
  39  * to close a stream (g_output_stream_close()) and to flush pending writes
  40  * (g_output_stream_flush()).
  41  *
  42  * To copy the content of an input stream to an output stream without
  43  * manually handling the reads and writes, use g_output_stream_splice().
  44  *
  45  * All of these functions have async variants too.
  46  **/
  47
  48 G_DEFINE_ABSTRACT_TYPE (GOutputStream, g_output_stream, G_TYPE_OBJECT);
  49
  50 struct _GOutputStreamPrivate {
  51   guint closed : 1;
  52   guint pending : 1;
  53   guint closing : 1;
  54   GAsyncReadyCallback outstanding_callback;
  55 };
  56
  57 static gssize   g_output_stream_real_splice        (GOutputStream             *stream,
  58                                                     GInputStream              *source,
  59                                                     GOutputStreamSpliceFlags   flags,
  60                                                     GCancellable              *cancellable,
  61                                                     GError                   **error);
  62 static void     g_output_stream_real_write_async   (GOutputStream             *stream,
  63                                                     const void                *buffer,
  64                                                     gsize                      count,
  65                                                     int                        io_priority,
  66                                                     GCancellable              *cancellable,
  67                                                     GAsyncReadyCallback        callback,
  68                                                     gpointer                   data);
  69 static gssize   g_output_stream_real_write_finish  (GOutputStream             *stream,
  70                                                     GAsyncResult              *result,
  71                                                     GError                   **error);
  72 static void     g_output_stream_real_splice_async  (GOutputStream             *stream,
  73                                                     GInputStream              *source,
  74                                                     GOutputStreamSpliceFlags   flags,
  75                                                     int                        io_priority,
  76                                                     GCancellable              *cancellable,
  77                                                     GAsyncReadyCallback        callback,
  78                                                     gpointer                   data);
  79 static gssize   g_output_stream_real_splice_finish (GOutputStream             *stream,
  80                                                     GAsyncResult              *result,
  81                                                     GError                   **error);
  82 static void     g_output_stream_real_flush_async   (GOutputStream             *stream,
  83                                                     int                        io_priority,
  84                                                     GCancellable              *cancellable,
  85                                                     GAsyncReadyCallback        callback,
  86                                                     gpointer                   data);
  87 static gboolean g_output_stream_real_flush_finish  (GOutputStream             *stream,
  88                                                     GAsyncResult              *result,
  89                                                     GError                   **error);
  90 static void     g_output_stream_real_close_async   (GOutputStream             *stream,
  91                                                     int                        io_priority,
  92                                                     GCancellable              *cancellable,
  93                                                     GAsyncReadyCallback        callback,
  94                                                     gpointer                   data);
  95 static gboolean g_output_stream_real_close_finish  (GOutputStream             *stream,
  96                                                     GAsyncResult              *result,
  97                                                     GError                   **error);
  98
  99 static void
 100 g_output_stream_finalize (GObject *object)
 101 {
 102   G_OBJECT_CLASS (g_output_stream_parent_class)->finalize (object);
 103 }
 104
 105 static void
 106 g_output_stream_dispose (GObject *object)
 107 {
 108   GOutputStream *stream;
 109
 110   stream = G_OUTPUT_STREAM (object);
 111
 112   if (!stream->priv->closed)
 113     g_output_stream_close (stream, NULL, NULL);
 114
 115   G_OBJECT_CLASS (g_output_stream_parent_class)->dispose (object);
 116 }
 117
 118 static void
 119 g_output_stream_class_init (GOutputStreamClass *klass)
 120 {
 121   GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
 122
 123   g_type_class_add_private (klass, sizeof (GOutputStreamPrivate));
 124
 125   gobject_class->finalize = g_output_stream_finalize;
 126   gobject_class->dispose = g_output_stream_dispose;
 127
 128   klass->splice = g_output_stream_real_splice;
 129
 130   klass->write_async = g_output_stream_real_write_async;
 131   klass->write_finish = g_output_stream_real_write_finish;
 132   klass->splice_async = g_output_stream_real_splice_async;
 133   klass->splice_finish = g_output_stream_real_splice_finish;
 134   klass->flush_async = g_output_stream_real_flush_async;
 135   klass->flush_finish = g_output_stream_real_flush_finish;
 136   klass->close_async = g_output_stream_real_close_async;
 137   klass->close_finish = g_output_stream_real_close_finish;
 138 }
 139
 140 static void
 141 g_output_stream_init (GOutputStream *stream)
 142 {
 143   stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (stream,
 144                                               G_TYPE_OUTPUT_STREAM,
 145                                               GOutputStreamPrivate);
 146 }
 147
 148 /**
 149  * g_output_stream_write:
 150  * @stream: a #GOutputStream.
 151  * @buffer: (array length=count) (element-type uint8): the buffer containing the data to write.
 152  * @count: the number of bytes to write
 153  * @cancellable: optional cancellable object
 154  * @error: location to store the error occuring, or %NULL to ignore
 155  *
 156  * Tries to write @count bytes from @buffer into the stream. Will block
 157  * during the operation.
 158  *
 159  * If count is zero returns zero and does nothing. A value of @count
 160  * larger than %G_MAXSSIZE will cause a %G_IO_ERROR_INVALID_ARGUMENT error.
 161  *
 162  * On success, the number of bytes written to the stream is returned.
 163  * It is not an error if this is not the same as the requested size, as it
 164  * can happen e.g. on a partial i/o error, or if there is not enough
 165  * storage in the stream. All writes either block until at least one byte
 166  * is written, so zero is never returned (unless @count is zero).
 167  *
 168  * If @cancellable is not NULL, then the operation can be cancelled by
 169  * triggering the cancellable object from another thread. If the operation
 170  * was cancelled, the error G_IO_ERROR_CANCELLED will be returned. If an
 171  * operation was partially finished when the operation was cancelled the
 172  * partial result will be returned, without an error.
 173  *
 174  * On error -1 is returned and @error is set accordingly.
 175  *
 176  * Return value: Number of bytes written, or -1 on error
 177  **/
 178 gssize
 179 g_output_stream_write (GOutputStream  *stream,
 180                        const void     *buffer,
 181                        gsize           count,
 182                        GCancellable   *cancellable,
 183                        GError        **error)
 184 {
 185   GOutputStreamClass *class;
 186   gssize res;
 187
 188   g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), -1);
 189   g_return_val_if_fail (buffer != NULL, 0);
 190
 191   if (count == 0)
 192     return 0;
 193
 194   if (((gssize) count) < 0)
 195     {
 196       g_set_error (error, G_IO_ERROR, G_IO_ERROR_INVALID_ARGUMENT,
 197                    _("Too large count value passed to %s"), G_STRFUNC);
 198       return -1;
 199     }
 200
 201   class = G_OUTPUT_STREAM_GET_CLASS (stream);
 202
 203   if (class->write_fn == NULL)
 204     {
 205       g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 206                            _("Output stream doesn't implement write"));
 207       return -1;
 208     }
 209
 210   if (!g_output_stream_set_pending (stream, error))
 211     return -1;
 212
 213   if (cancellable)
 214     g_cancellable_push_current (cancellable);
 215
 216   res = class->write_fn (stream, buffer, count, cancellable, error);
 217
 218   if (cancellable)
 219     g_cancellable_pop_current (cancellable);
 220
 221   g_output_stream_clear_pending (stream);
 222
 223   return res;
 224 }
 225
 226 /**
 227  * g_output_stream_write_all:
 228  * @stream: a #GOutputStream.
 229  * @buffer: (array length=count) (element-type uint8): the buffer containing the data to write.
 230  * @count: the number of bytes to write
 231  * @bytes_written: location to store the number of bytes that was
 232  *     written to the stream
 233  * @cancellable: optional #GCancellable object, %NULL to ignore.
 234  * @error: location to store the error occuring, or %NULL to ignore
 235  *
 236  * Tries to write @count bytes from @buffer into the stream. Will block
 237  * during the operation.
 238  *
 239  * This function is similar to g_output_stream_write(), except it tries to
 240  * write as many bytes as requested, only stopping on an error.
 241  *
 242  * On a successful write of @count bytes, %TRUE is returned, and @bytes_written
 243  * is set to @count.
 244  *
 245  * If there is an error during the operation FALSE is returned and @error
 246  * is set to indicate the error status, @bytes_written is updated to contain
 247  * the number of bytes written into the stream before the error occurred.
 248  *
 249  * Return value: %TRUE on success, %FALSE if there was an error
 250  **/
 251 gboolean
 252 g_output_stream_write_all (GOutputStream  *stream,
 253                            const void     *buffer,
 254                            gsize           count,
 255                            gsize          *bytes_written,
 256                            GCancellable   *cancellable,
 257                            GError        **error)
 258 {
 259   gsize _bytes_written;
 260   gssize res;
 261
 262   g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), FALSE);
 263   g_return_val_if_fail (buffer != NULL, FALSE);
 264
 265   _bytes_written = 0;
 266   while (_bytes_written < count)
 267     {
 268       res = g_output_stream_write (stream, (char *)buffer + _bytes_written, count - _bytes_written,
 269                                    cancellable, error);
 270       if (res == -1)
 271         {
 272           if (bytes_written)
 273             *bytes_written = _bytes_written;
 274           return FALSE;
 275         }
 276
 277       if (res == 0)
 278         g_warning ("Write returned zero without error");
 279
 280       _bytes_written += res;
 281     }
 282
 283   if (bytes_written)
 284     *bytes_written = _bytes_written;
 285
 286   return TRUE;
 287 }
 288
 289 /**
 290  * g_output_stream_flush:
 291  * @stream: a #GOutputStream.
 292  * @cancellable: optional cancellable object
 293  * @error: location to store the error occuring, or %NULL to ignore
 294  *
 295  * Flushed any outstanding buffers in the stream. Will block during
 296  * the operation. Closing the stream will implicitly cause a flush.
 297  *
 298  * This function is optional for inherited classes.
 299  *
 300  * If @cancellable is not %NULL, then the operation can be cancelled by
 301  * triggering the cancellable object from another thread. If the operation
 302  * was cancelled, the error %G_IO_ERROR_CANCELLED will be returned.
 303  *
 304  * Return value: %TRUE on success, %FALSE on error
 305  **/
 306 gboolean
 307 g_output_stream_flush (GOutputStream  *stream,
 308                        GCancellable   *cancellable,
 309                        GError        **error)
 310 {
 311   GOutputStreamClass *class;
 312   gboolean res;
 313
 314   g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), FALSE);
 315
 316   if (!g_output_stream_set_pending (stream, error))
 317     return FALSE;
 318
 319   class = G_OUTPUT_STREAM_GET_CLASS (stream);
 320
 321   res = TRUE;
 322   if (class->flush)
 323     {
 324       if (cancellable)
 325         g_cancellable_push_current (cancellable);
 326
 327       res = class->flush (stream, cancellable, error);
 328
 329       if (cancellable)
 330         g_cancellable_pop_current (cancellable);
 331     }
 332
 333   g_output_stream_clear_pending (stream);
 334
 335   return res;
 336 }
 337
 338 /**
 339  * g_output_stream_splice:
 340  * @stream: a #GOutputStream.
 341  * @source: a #GInputStream.
 342  * @flags: a set of #GOutputStreamSpliceFlags.
 343  * @cancellable: optional #GCancellable object, %NULL to ignore.
 344  * @error: a #GError location to store the error occuring, or %NULL to
 345  * ignore.
 346  *
 347  * Splices an input stream into an output stream.
 348  *
 349  * Returns: a #gssize containing the size of the data spliced, or
 350  *     -1 if an error occurred.
 351  **/
 352 gssize
 353 g_output_stream_splice (GOutputStream             *stream,
 354                         GInputStream              *source,
 355                         GOutputStreamSpliceFlags   flags,
 356                         GCancellable              *cancellable,
 357                         GError                   **error)
 358 {
 359   GOutputStreamClass *class;
 360   gssize bytes_copied;
 361
 362   g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), -1);
 363   g_return_val_if_fail (G_IS_INPUT_STREAM (source), -1);
 364
 365   if (g_input_stream_is_closed (source))
 366     {
 367       g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
 368                            _("Source stream is already closed"));
 369       return -1;
 370     }
 371
 372   if (!g_output_stream_set_pending (stream, error))
 373     return -1;
 374
 375   class = G_OUTPUT_STREAM_GET_CLASS (stream);
 376
 377   if (cancellable)
 378     g_cancellable_push_current (cancellable);
 379
 380   bytes_copied = class->splice (stream, source, flags, cancellable, error);
 381
 382   if (cancellable)
 383     g_cancellable_pop_current (cancellable);
 384
 385   g_output_stream_clear_pending (stream);
 386
 387   return bytes_copied;
 388 }
 389
 390 static gssize
 391 g_output_stream_real_splice (GOutputStream             *stream,
 392                              GInputStream              *source,
 393                              GOutputStreamSpliceFlags   flags,
 394                              GCancellable              *cancellable,
 395                              GError                   **error)
 396 {
 397   GOutputStreamClass *class = G_OUTPUT_STREAM_GET_CLASS (stream);
 398   gssize n_read, n_written;
 399   gssize bytes_copied;
 400   char buffer[8192], *p;
 401   gboolean res;
 402
 403   bytes_copied = 0;
 404   if (class->write_fn == NULL)
 405     {
 406       g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 407                            _("Output stream doesn't implement write"));
 408       res = FALSE;
 409       goto notsupported;
 410     }
 411
 412   res = TRUE;
 413   do
 414     {
 415       n_read = g_input_stream_read (source, buffer, sizeof (buffer), cancellable, error);
 416       if (n_read == -1)
 417         {
 418           res = FALSE;
 419           break;
 420         }
 421
 422       if (n_read == 0)
 423         break;
 424
 425       p = buffer;
 426       while (n_read > 0)
 427         {
 428           n_written = class->write_fn (stream, p, n_read, cancellable, error);
 429           if (n_written == -1)
 430             {
 431               res = FALSE;
 432               break;
 433             }
 434
 435           p += n_written;
 436           n_read -= n_written;
 437           bytes_copied += n_written;
 438         }
 439     }
 440   while (res);
 441
 442  notsupported:
 443   if (!res)
 444     error = NULL; /* Ignore further errors */
 445
 446   if (flags & G_OUTPUT_STREAM_SPLICE_CLOSE_SOURCE)
 447     {
 448       /* Don't care about errors in source here */
 449       g_input_stream_close (source, cancellable, NULL);
 450     }
 451
 452   if (flags & G_OUTPUT_STREAM_SPLICE_CLOSE_TARGET)
 453     {
 454       /* But write errors on close are bad! */
 455       if (class->close_fn &&
 456           !class->close_fn (stream, cancellable, error))
 457         res = FALSE;
 458     }
 459
 460   if (res)
 461     return bytes_copied;
 462
 463   return -1;
 464 }
 465
 466
 467 /**
 468  * g_output_stream_close:
 469  * @stream: A #GOutputStream.
 470  * @cancellable: optional cancellable object
 471  * @error: location to store the error occuring, or %NULL to ignore
 472  *
 473  * Closes the stream, releasing resources related to it.
 474  *
 475  * Once the stream is closed, all other operations will return %G_IO_ERROR_CLOSED.
 476  * Closing a stream multiple times will not return an error.
 477  *
 478  * Closing a stream will automatically flush any outstanding buffers in the
 479  * stream.
 480  *
 481  * Streams will be automatically closed when the last reference
 482  * is dropped, but you might want to call this function to make sure
 483  * resources are released as early as possible.
 484  *
 485  * Some streams might keep the backing store of the stream (e.g. a file descriptor)
 486  * open after the stream is closed. See the documentation for the individual
 487  * stream for details.
 488  *
 489  * On failure the first error that happened will be reported, but the close
 490  * operation will finish as much as possible. A stream that failed to
 491  * close will still return %G_IO_ERROR_CLOSED for all operations. Still, it
 492  * is important to check and report the error to the user, otherwise
 493  * there might be a loss of data as all data might not be written.
 494  *
 495  * If @cancellable is not NULL, then the operation can be cancelled by
 496  * triggering the cancellable object from another thread. If the operation
 497  * was cancelled, the error %G_IO_ERROR_CANCELLED will be returned.
 498  * Cancelling a close will still leave the stream closed, but there some streams
 499  * can use a faster close that doesn't block to e.g. check errors. On
 500  * cancellation (as with any error) there is no guarantee that all written
 501  * data will reach the target.
 502  *
 503  * Return value: %TRUE on success, %FALSE on failure
 504  **/
 505 gboolean
 506 g_output_stream_close (GOutputStream  *stream,
 507                        GCancellable   *cancellable,
 508                        GError        **error)
 509 {
 510   GOutputStreamClass *class;
 511   gboolean res;
 512
 513   g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), FALSE);
 514
 515   class = G_OUTPUT_STREAM_GET_CLASS (stream);
 516
 517   if (stream->priv->closed)
 518     return TRUE;
 519
 520   if (!g_output_stream_set_pending (stream, error))
 521     return FALSE;
 522
 523   stream->priv->closing = TRUE;
 524
 525   if (cancellable)
 526     g_cancellable_push_current (cancellable);
 527
 528   if (class->flush)
 529     res = class->flush (stream, cancellable, error);
 530   else
 531     res = TRUE;
 532
 533   if (!res)
 534     {
 535       /* flushing caused the error that we want to return,
 536        * but we still want to close the underlying stream if possible
 537        */
 538       if (class->close_fn)
 539         class->close_fn (stream, cancellable, NULL);
 540     }
 541   else
 542     {
 543       res = TRUE;
 544       if (class->close_fn)
 545         res = class->close_fn (stream, cancellable, error);
 546     }
 547
 548   if (cancellable)
 549     g_cancellable_pop_current (cancellable);
 550
 551   stream->priv->closing = FALSE;
 552   stream->priv->closed = TRUE;
 553   g_output_stream_clear_pending (stream);
 554
 555   return res;
 556 }
 557
 558 static void
 559 async_ready_callback_wrapper (GObject      *source_object,
 560                               GAsyncResult *res,
 561                               gpointer      user_data)
 562 {
 563   GOutputStream *stream = G_OUTPUT_STREAM (source_object);
 564
 565   g_output_stream_clear_pending (stream);
 566   if (stream->priv->outstanding_callback)
 567     (*stream->priv->outstanding_callback) (source_object, res, user_data);
 568   g_object_unref (stream);
 569 }
 570
 571 typedef struct {
 572   gint io_priority;
 573   GCancellable *cancellable;
 574   GError *flush_error;
 575   gpointer user_data;
 576 } CloseUserData;
 577
 578 static void
 579 async_ready_close_callback_wrapper (GObject      *source_object,
 580                                     GAsyncResult *res,
 581                                     gpointer      user_data)
 582 {
 583   GOutputStream *stream = G_OUTPUT_STREAM (source_object);
 584   CloseUserData *data = user_data;
 585
 586   stream->priv->closing = FALSE;
 587   stream->priv->closed = TRUE;
 588
 589   g_output_stream_clear_pending (stream);
 590
 591   if (stream->priv->outstanding_callback)
 592     {
 593       if (data->flush_error != NULL)
 594         {
 595           GSimpleAsyncResult *err;
 596
 597           err = g_simple_async_result_new_from_error (source_object,
 598                                                       stream->priv->outstanding_callback,
 599                                                       data->user_data,
 600                                                       data->flush_error);
 601
 602           (*stream->priv->outstanding_callback) (source_object,
 603                                                  G_ASYNC_RESULT (err),
 604                                                  data->user_data);
 605           g_object_unref (err);
 606         }
 607       else
 608         {
 609           (*stream->priv->outstanding_callback) (source_object,
 610                                                  res,
 611                                                  data->user_data);
 612         }
 613     }
 614
 615   g_object_unref (stream);
 616
 617   if (data->cancellable)
 618     g_object_unref (data->cancellable);
 619
 620   if (data->flush_error)
 621     g_error_free (data->flush_error);
 622
 623   g_slice_free (CloseUserData, data);
 624 }
 625
 626 static void
 627 async_ready_close_flushed_callback_wrapper (GObject      *source_object,
 628                                             GAsyncResult *res,
 629                                             gpointer      user_data)
 630 {
 631   GOutputStream *stream = G_OUTPUT_STREAM (source_object);
 632   GOutputStreamClass *class;
 633   CloseUserData *data = user_data;
 634   GSimpleAsyncResult *simple;
 635
 636   /* propagate the possible error */
 637   if (G_IS_SIMPLE_ASYNC_RESULT (res))
 638     {
 639       simple = G_SIMPLE_ASYNC_RESULT (res);
 640       g_simple_async_result_propagate_error (simple, &data->flush_error);
 641     }
 642
 643   class = G_OUTPUT_STREAM_GET_CLASS (stream);
 644
 645   /* we still close, even if there was a flush error */
 646   class->close_async (stream, data->io_priority, data->cancellable,
 647                       async_ready_close_callback_wrapper, user_data);
 648 }
 649
 650 /**
 651  * g_output_stream_write_async:
 652  * @stream: A #GOutputStream.
 653  * @buffer: (array length=count) (element-type uint8): the buffer containing the data to write.
 654  * @count: the number of bytes to write
 655  * @io_priority: the io priority of the request.
 656  * @cancellable: optional #GCancellable object, %NULL to ignore.
 657  * @callback: callback to call when the request is satisfied
 658  * @user_data: the data to pass to callback function
 659  *
 660  * Request an asynchronous write of @count bytes from @buffer into
 661  * the stream. When the operation is finished @callback will be called.
 662  * You can then call g_output_stream_write_finish() to get the result of the
 663  * operation.
 664  *
 665  * During an async request no other sync and async calls are allowed,
 666  * and will result in %G_IO_ERROR_PENDING errors.
 667  *
 668  * A value of @count larger than %G_MAXSSIZE will cause a
 669  * %G_IO_ERROR_INVALID_ARGUMENT error.
 670  *
 671  * On success, the number of bytes written will be passed to the
 672  * @callback. It is not an error if this is not the same as the
 673  * requested size, as it can happen e.g. on a partial I/O error,
 674  * but generally we try to write as many bytes as requested.
 675  *
 676  * You are guaranteed that this method will never fail with
 677  * %G_IO_ERROR_WOULD_BLOCK - if @stream can't accept more data, the
 678  * method will just wait until this changes.
 679  *
 680  * Any outstanding I/O request with higher priority (lower numerical
 681  * value) will be executed before an outstanding request with lower
 682  * priority. Default priority is %G_PRIORITY_DEFAULT.
 683  *
 684  * The asyncronous methods have a default fallback that uses threads
 685  * to implement asynchronicity, so they are optional for inheriting
 686  * classes. However, if you override one you must override all.
 687  *
 688  * For the synchronous, blocking version of this function, see
 689  * g_output_stream_write().
 690  **/
 691 void
 692 g_output_stream_write_async (GOutputStream       *stream,
 693                              const void          *buffer,
 694                              gsize                count,
 695                              int                  io_priority,
 696                              GCancellable        *cancellable,
 697                              GAsyncReadyCallback  callback,
 698                              gpointer             user_data)
 699 {
 700   GOutputStreamClass *class;
 701   GSimpleAsyncResult *simple;
 702   GError *error = NULL;
 703
 704   g_return_if_fail (G_IS_OUTPUT_STREAM (stream));
 705   g_return_if_fail (buffer != NULL);
 706
 707   if (count == 0)
 708     {
 709       simple = g_simple_async_result_new (G_OBJECT (stream),
 710                                           callback,
 711                                           user_data,
 712                                           g_output_stream_write_async);
 713       g_simple_async_result_complete_in_idle (simple);
 714       g_object_unref (simple);
 715       return;
 716     }
 717
 718   if (((gssize) count) < 0)
 719     {
 720       g_simple_async_report_error_in_idle (G_OBJECT (stream),
 721                                            callback,
 722                                            user_data,
 723                                            G_IO_ERROR, G_IO_ERROR_INVALID_ARGUMENT,
 724                                            _("Too large count value passed to %s"),
 725                                            G_STRFUNC);
 726       return;
 727     }
 728
 729   if (!g_output_stream_set_pending (stream, &error))
 730     {
 731       g_simple_async_report_gerror_in_idle (G_OBJECT (stream),
 732                                             callback,
 733                                             user_data,
 734                                             error);
 735       g_error_free (error);
 736       return;
 737     }
 738
 739   class = G_OUTPUT_STREAM_GET_CLASS (stream);
 740
 741   stream->priv->outstanding_callback = callback;
 742   g_object_ref (stream);
 743   class->write_async (stream, buffer, count, io_priority, cancellable,
 744                       async_ready_callback_wrapper, user_data);
 745 }
 746
 747 /**
 748  * g_output_stream_write_finish:
 749  * @stream: a #GOutputStream.
 750  * @result: a #GAsyncResult.
 751  * @error: a #GError location to store the error occuring, or %NULL to
 752  * ignore.
 753  *
 754  * Finishes a stream write operation.
 755  *
 756  * Returns: a #gssize containing the number of bytes written to the stream.
 757  **/
 758 gssize
 759 g_output_stream_write_finish (GOutputStream  *stream,
 760                               GAsyncResult   *result,
 761                               GError        **error)
 762 {
 763   GSimpleAsyncResult *simple;
 764   GOutputStreamClass *class;
 765
 766   g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), -1);
 767   g_return_val_if_fail (G_IS_ASYNC_RESULT (result), -1);
 768
 769   if (G_IS_SIMPLE_ASYNC_RESULT (result))
 770     {
 771       simple = G_SIMPLE_ASYNC_RESULT (result);
 772       if (g_simple_async_result_propagate_error (simple, error))
 773         return -1;
 774
 775       /* Special case writes of 0 bytes */
 776       if (g_simple_async_result_get_source_tag (simple) == g_output_stream_write_async)
 777         return 0;
 778     }
 779
 780   class = G_OUTPUT_STREAM_GET_CLASS (stream);
 781   return class->write_finish (stream, result, error);
 782 }
 783
 784 typedef struct {
 785   GInputStream *source;
 786   gpointer user_data;
 787   GAsyncReadyCallback callback;
 788 } SpliceUserData;
 789
 790 static void
 791 async_ready_splice_callback_wrapper (GObject      *source_object,
 792                                      GAsyncResult *res,
 793                                      gpointer     _data)
 794 {
 795   GOutputStream *stream = G_OUTPUT_STREAM (source_object);
 796   SpliceUserData *data = _data;
 797
 798   g_output_stream_clear_pending (stream);
 799
 800   if (data->callback)
 801     (*data->callback) (source_object, res, data->user_data);
 802
 803   g_object_unref (stream);
 804   g_object_unref (data->source);
 805   g_free (data);
 806 }
 807
 808 /**
 809  * g_output_stream_splice_async:
 810  * @stream: a #GOutputStream.
 811  * @source: a #GInputStream.
 812  * @flags: a set of #GOutputStreamSpliceFlags.
 813  * @io_priority: the io priority of the request.
 814  * @cancellable: optional #GCancellable object, %NULL to ignore.
 815  * @callback: a #GAsyncReadyCallback.
 816  * @user_data: user data passed to @callback.
 817  *
 818  * Splices a stream asynchronously.
 819  * When the operation is finished @callback will be called.
 820  * You can then call g_output_stream_splice_finish() to get the
 821  * result of the operation.
 822  *
 823  * For the synchronous, blocking version of this function, see
 824  * g_output_stream_splice().
 825  **/
 826 void
 827 g_output_stream_splice_async (GOutputStream            *stream,
 828                               GInputStream             *source,
 829                               GOutputStreamSpliceFlags  flags,
 830                               int                       io_priority,
 831                               GCancellable             *cancellable,
 832                               GAsyncReadyCallback       callback,
 833                               gpointer                  user_data)
 834 {
 835   GOutputStreamClass *class;
 836   SpliceUserData *data;
 837   GError *error = NULL;
 838
 839   g_return_if_fail (G_IS_OUTPUT_STREAM (stream));
 840   g_return_if_fail (G_IS_INPUT_STREAM (source));
 841
 842   if (g_input_stream_is_closed (source))
 843     {
 844       g_simple_async_report_error_in_idle (G_OBJECT (stream),
 845                                            callback,
 846                                            user_data,
 847                                            G_IO_ERROR, G_IO_ERROR_CLOSED,
 848                                            _("Source stream is already closed"));
 849       return;
 850     }
 851
 852   if (!g_output_stream_set_pending (stream, &error))
 853     {
 854       g_simple_async_report_gerror_in_idle (G_OBJECT (stream),
 855                                             callback,
 856                                             user_data,
 857                                             error);
 858       g_error_free (error);
 859       return;
 860     }
 861
 862   class = G_OUTPUT_STREAM_GET_CLASS (stream);
 863
 864   data = g_new0 (SpliceUserData, 1);
 865   data->callback = callback;
 866   data->user_data = user_data;
 867   data->source = g_object_ref (source);
 868
 869   g_object_ref (stream);
 870   class->splice_async (stream, source, flags, io_priority, cancellable,
 871                       async_ready_splice_callback_wrapper, data);
 872 }
 873
 874 /**
 875  * g_output_stream_splice_finish:
 876  * @stream: a #GOutputStream.
 877  * @result: a #GAsyncResult.
 878  * @error: a #GError location to store the error occuring, or %NULL to
 879  * ignore.
 880  *
 881  * Finishes an asynchronous stream splice operation.
 882  *
 883  * Returns: a #gssize of the number of bytes spliced.
 884  **/
 885 gssize
 886 g_output_stream_splice_finish (GOutputStream  *stream,
 887                                GAsyncResult   *result,
 888                                GError        **error)
 889 {
 890   GSimpleAsyncResult *simple;
 891   GOutputStreamClass *class;
 892
 893   g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), -1);
 894   g_return_val_if_fail (G_IS_ASYNC_RESULT (result), -1);
 895
 896   if (G_IS_SIMPLE_ASYNC_RESULT (result))
 897     {
 898       simple = G_SIMPLE_ASYNC_RESULT (result);
 899       if (g_simple_async_result_propagate_error (simple, error))
 900         return -1;
 901     }
 902
 903   class = G_OUTPUT_STREAM_GET_CLASS (stream);
 904   return class->splice_finish (stream, result, error);
 905 }
 906
 907 /**
 908  * g_output_stream_flush_async:
 909  * @stream: a #GOutputStream.
 910  * @io_priority: the io priority of the request.
 911  * @cancellable: optional #GCancellable object, %NULL to ignore.
 912  * @callback: a #GAsyncReadyCallback to call when the request is satisfied
 913  * @user_data: the data to pass to callback function
 914  *
 915  * Flushes a stream asynchronously.
 916  * For behaviour details see g_output_stream_flush().
 917  *
 918  * When the operation is finished @callback will be
 919  * called. You can then call g_output_stream_flush_finish() to get the
 920  * result of the operation.
 921  **/
 922 void
 923 g_output_stream_flush_async (GOutputStream       *stream,
 924                              int                  io_priority,
 925                              GCancellable        *cancellable,
 926                              GAsyncReadyCallback  callback,
 927                              gpointer             user_data)
 928 {
 929   GOutputStreamClass *class;
 930   GSimpleAsyncResult *simple;
 931   GError *error = NULL;
 932
 933   g_return_if_fail (G_IS_OUTPUT_STREAM (stream));
 934
 935   if (!g_output_stream_set_pending (stream, &error))
 936     {
 937       g_simple_async_report_gerror_in_idle (G_OBJECT (stream),
 938                                             callback,
 939                                             user_data,
 940                                             error);
 941       g_error_free (error);
 942       return;
 943     }
 944
 945   stream->priv->outstanding_callback = callback;
 946   g_object_ref (stream);
 947
 948   class = G_OUTPUT_STREAM_GET_CLASS (stream);
 949
 950   if (class->flush_async == NULL)
 951     {
 952       simple = g_simple_async_result_new (G_OBJECT (stream),
 953                                           async_ready_callback_wrapper,
 954                                           user_data,
 955                                           g_output_stream_flush_async);
 956       g_simple_async_result_complete_in_idle (simple);
 957       g_object_unref (simple);
 958       return;
 959     }
 960
 961   class->flush_async (stream, io_priority, cancellable,
 962                       async_ready_callback_wrapper, user_data);
 963 }
 964
 965 /**
 966  * g_output_stream_flush_finish:
 967  * @stream: a #GOutputStream.
 968  * @result: a GAsyncResult.
 969  * @error: a #GError location to store the error occuring, or %NULL to
 970  * ignore.
 971  *
 972  * Finishes flushing an output stream.
 973  *
 974  * Returns: %TRUE if flush operation suceeded, %FALSE otherwise.
 975  **/
 976 gboolean
 977 g_output_stream_flush_finish (GOutputStream  *stream,
 978                               GAsyncResult   *result,
 979                               GError        **error)
 980 {
 981   GSimpleAsyncResult *simple;
 982   GOutputStreamClass *klass;
 983
 984   g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), FALSE);
 985   g_return_val_if_fail (G_IS_ASYNC_RESULT (result), FALSE);
 986
 987   if (G_IS_SIMPLE_ASYNC_RESULT (result))
 988     {
 989       simple = G_SIMPLE_ASYNC_RESULT (result);
 990       if (g_simple_async_result_propagate_error (simple, error))
 991         return FALSE;
 992
 993       /* Special case default implementation */
 994       if (g_simple_async_result_get_source_tag (simple) == g_output_stream_flush_async)
 995         return TRUE;
 996     }
 997
 998   klass = G_OUTPUT_STREAM_GET_CLASS (stream);
 999   return klass->flush_finish (stream, result, error);
1000 }
1001
1002
1003 /**
1004  * g_output_stream_close_async:
1005  * @stream: A #GOutputStream.
1006  * @io_priority: the io priority of the request.
1007  * @callback: callback to call when the request is satisfied
1008  * @user_data: the data to pass to callback function
1009  * @cancellable: optional cancellable object
1010  *
1011  * Requests an asynchronous close of the stream, releasing resources
1012  * related to it. When the operation is finished @callback will be
1013  * called. You can then call g_output_stream_close_finish() to get
1014  * the result of the operation.
1015  *
1016  * For behaviour details see g_output_stream_close().
1017  *
1018  * The asyncronous methods have a default fallback that uses threads
1019  * to implement asynchronicity, so they are optional for inheriting
1020  * classes. However, if you override one you must override all.
1021  **/
1022 void
1023 g_output_stream_close_async (GOutputStream       *stream,
1024                              int                  io_priority,
1025                              GCancellable        *cancellable,
1026                              GAsyncReadyCallback  callback,
1027                              gpointer             user_data)
1028 {
1029   GOutputStreamClass *class;
1030   GSimpleAsyncResult *simple;
1031   GError *error = NULL;
1032   CloseUserData *data;
1033
1034   g_return_if_fail (G_IS_OUTPUT_STREAM (stream));
1035
1036   if (stream->priv->closed)
1037     {
1038       simple = g_simple_async_result_new (G_OBJECT (stream),
1039                                           callback,
1040                                           user_data,
1041                                           g_output_stream_close_async);
1042       g_simple_async_result_complete_in_idle (simple);
1043       g_object_unref (simple);
1044       return;
1045     }
1046
1047   if (!g_output_stream_set_pending (stream, &error))
1048     {
1049       g_simple_async_report_gerror_in_idle (G_OBJECT (stream),
1050                                             callback,
1051                                             user_data,
1052                                             error);
1053       g_error_free (error);
1054       return;
1055     }
1056
1057   class = G_OUTPUT_STREAM_GET_CLASS (stream);
1058   stream->priv->closing = TRUE;
1059   stream->priv->outstanding_callback = callback;
1060   g_object_ref (stream);
1061
1062   data = g_slice_new0 (CloseUserData);
1063
1064   if (cancellable != NULL)
1065     data->cancellable = g_object_ref (cancellable);
1066
1067   data->io_priority = io_priority;
1068   data->user_data = user_data;
1069
1070   /* Call close_async directly if there is no need to flush, or if the flush
1071      can be done sync (in the output stream async close thread) */
1072   if (class->flush_async == NULL ||
1073       (class->flush_async == g_output_stream_real_flush_async &&
1074        (class->flush == NULL || class->close_async == g_output_stream_real_close_async)))
1075     {
1076       class->close_async (stream, io_priority, cancellable,
1077                           async_ready_close_callback_wrapper, data);
1078     }
1079   else
1080     {
1081       /* First do an async flush, then do the async close in the callback
1082          wrapper (see async_ready_close_flushed_callback_wrapper) */
1083       class->flush_async (stream, io_priority, cancellable,
1084                           async_ready_close_flushed_callback_wrapper, data);
1085     }
1086 }
1087
1088 /**
1089  * g_output_stream_close_finish:
1090  * @stream: a #GOutputStream.
1091  * @result: a #GAsyncResult.
1092  * @error: a #GError location to store the error occuring, or %NULL to
1093  * ignore.
1094  *
1095  * Closes an output stream.
1096  *
1097  * Returns: %TRUE if stream was successfully closed, %FALSE otherwise.
1098  **/
1099 gboolean
1100 g_output_stream_close_finish (GOutputStream  *stream,
1101                               GAsyncResult   *result,
1102                               GError        **error)
1103 {
1104   GSimpleAsyncResult *simple;
1105   GOutputStreamClass *class;
1106
1107   g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), FALSE);
1108   g_return_val_if_fail (G_IS_ASYNC_RESULT (result), FALSE);
1109
1110   if (G_IS_SIMPLE_ASYNC_RESULT (result))
1111     {
1112       simple = G_SIMPLE_ASYNC_RESULT (result);
1113       if (g_simple_async_result_propagate_error (simple, error))
1114         return FALSE;
1115
1116       /* Special case already closed */
1117       if (g_simple_async_result_get_source_tag (simple) == g_output_stream_close_async)
1118         return TRUE;
1119     }
1120
1121   class = G_OUTPUT_STREAM_GET_CLASS (stream);
1122   return class->close_finish (stream, result, error);
1123 }
1124
1125 /**
1126  * g_output_stream_is_closed:
1127  * @stream: a #GOutputStream.
1128  *
1129  * Checks if an output stream has already been closed.
1130  *
1131  * Returns: %TRUE if @stream is closed. %FALSE otherwise.
1132  **/
1133 gboolean
1134 g_output_stream_is_closed (GOutputStream *stream)
1135 {
1136   g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), TRUE);
1137
1138   return stream->priv->closed;
1139 }
1140
1141 /**
1142  * g_output_stream_is_closing:
1143  * @stream: a #GOutputStream.
1144  *
1145  * Checks if an output stream is being closed. This can be
1146  * used inside e.g. a flush implementation to see if the
1147  * flush (or other i/o operation) is called from within
1148  * the closing operation.
1149  *
1150  * Returns: %TRUE if @stream is being closed. %FALSE otherwise.
1151  *
1152  * Since: 2.24
1153  **/
1154 gboolean
1155 g_output_stream_is_closing (GOutputStream *stream)
1156 {
1157   g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), TRUE);
1158
1159   return stream->priv->closing;
1160 }
1161
1162 /**
1163  * g_output_stream_has_pending:
1164  * @stream: a #GOutputStream.
1165  *
1166  * Checks if an ouput stream has pending actions.
1167  *
1168  * Returns: %TRUE if @stream has pending actions.
1169  **/
1170 gboolean
1171 g_output_stream_has_pending (GOutputStream *stream)
1172 {
1173   g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), FALSE);
1174
1175   return stream->priv->pending;
1176 }
1177
1178 /**
1179  * g_output_stream_set_pending:
1180  * @stream: a #GOutputStream.
1181  * @error: a #GError location to store the error occuring, or %NULL to
1182  * ignore.
1183  *
1184  * Sets @stream to have actions pending. If the pending flag is
1185  * already set or @stream is closed, it will return %FALSE and set
1186  * @error.
1187  *
1188  * Return value: %TRUE if pending was previously unset and is now set.
1189  **/
1190 gboolean
1191 g_output_stream_set_pending (GOutputStream *stream,
1192                              GError **error)
1193 {
1194   g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), FALSE);
1195
1196   if (stream->priv->closed)
1197     {
1198       g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
1199                            _("Stream is already closed"));
1200       return FALSE;
1201     }
1202
1203   if (stream->priv->pending)
1204     {
1205       g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PENDING,
1206                            /* Translators: This is an error you get if there is
1207                             * already an operation running against this stream when
1208                             * you try to start one */
1209                            _("Stream has outstanding operation"));
1210       return FALSE;
1211     }
1212
1213   stream->priv->pending = TRUE;
1214   return TRUE;
1215 }
1216
1217 /**
1218  * g_output_stream_clear_pending:
1219  * @stream: output stream
1220  *
1221  * Clears the pending flag on @stream.
1222  **/
1223 void
1224 g_output_stream_clear_pending (GOutputStream *stream)
1225 {
1226   g_return_if_fail (G_IS_OUTPUT_STREAM (stream));
1227
1228   stream->priv->pending = FALSE;
1229 }
1230
1231
1232 /********************************************
1233  *   Default implementation of async ops    *
1234  ********************************************/
1235
1236 typedef struct {
1237   const void         *buffer;
1238   gsize               count_requested;
1239   gssize              count_written;
1240 } WriteData;
1241
1242 static void
1243 write_async_thread (GSimpleAsyncResult *res,
1244                     GObject            *object,
1245                     GCancellable       *cancellable)
1246 {
1247   WriteData *op;
1248   GOutputStreamClass *class;
1249   GError *error = NULL;
1250
1251   class = G_OUTPUT_STREAM_GET_CLASS (object);
1252   op = g_simple_async_result_get_op_res_gpointer (res);
1253   op->count_written = class->write_fn (G_OUTPUT_STREAM (object), op->buffer, op->count_requested,
1254                                        cancellable, &error);
1255   if (op->count_written == -1)
1256     {
1257       g_simple_async_result_set_from_error (res, error);
1258       g_error_free (error);
1259     }
1260 }
1261
1262 static void
1263 g_output_stream_real_write_async (GOutputStream       *stream,
1264                                   const void          *buffer,
1265                                   gsize                count,
1266                                   int                  io_priority,
1267                                   GCancellable        *cancellable,
1268                                   GAsyncReadyCallback  callback,
1269                                   gpointer             user_data)
1270 {
1271   GSimpleAsyncResult *res;
1272   WriteData *op;
1273
1274   op = g_new0 (WriteData, 1);
1275   res = g_simple_async_result_new (G_OBJECT (stream), callback, user_data, g_output_stream_real_write_async);
1276   g_simple_async_result_set_op_res_gpointer (res, op, g_free);
1277   op->buffer = buffer;
1278   op->count_requested = count;
1279
1280   g_simple_async_result_run_in_thread (res, write_async_thread, io_priority, cancellable);
1281   g_object_unref (res);
1282 }
1283
1284 static gssize
1285 g_output_stream_real_write_finish (GOutputStream  *stream,
1286                                    GAsyncResult   *result,
1287                                    GError        **error)
1288 {
1289   GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
1290   WriteData *op;
1291
1292   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_output_stream_real_write_async);
1293   op = g_simple_async_result_get_op_res_gpointer (simple);
1294   return op->count_written;
1295 }
1296
1297 typedef struct {
1298   GInputStream *source;
1299   GOutputStreamSpliceFlags flags;
1300   gssize bytes_copied;
1301 } SpliceData;
1302
1303 static void
1304 splice_async_thread (GSimpleAsyncResult *result,
1305                      GObject            *object,
1306                      GCancellable       *cancellable)
1307 {
1308   SpliceData *op;
1309   GOutputStreamClass *class;
1310   GError *error = NULL;
1311   GOutputStream *stream;
1312
1313   stream = G_OUTPUT_STREAM (object);
1314   class = G_OUTPUT_STREAM_GET_CLASS (object);
1315   op = g_simple_async_result_get_op_res_gpointer (result);
1316
1317   op->bytes_copied = class->splice (stream,
1318                                     op->source,
1319                                     op->flags,
1320                                     cancellable,
1321                                     &error);
1322   if (op->bytes_copied == -1)
1323     {
1324       g_simple_async_result_set_from_error (result, error);
1325       g_error_free (error);
1326     }
1327 }
1328
1329 static void
1330 g_output_stream_real_splice_async (GOutputStream             *stream,
1331                                    GInputStream              *source,
1332                                    GOutputStreamSpliceFlags   flags,
1333                                    int                        io_priority,
1334                                    GCancellable              *cancellable,
1335                                    GAsyncReadyCallback        callback,
1336                                    gpointer                   user_data)
1337 {
1338   GSimpleAsyncResult *res;
1339   SpliceData *op;
1340
1341   op = g_new0 (SpliceData, 1);
1342   res = g_simple_async_result_new (G_OBJECT (stream), callback, user_data, g_output_stream_real_splice_async);
1343   g_simple_async_result_set_op_res_gpointer (res, op, g_free);
1344   op->flags = flags;
1345   op->source = source;
1346
1347   /* TODO: In the case where both source and destintion have
1348      non-threadbased async calls we can use a true async copy here */
1349
1350   g_simple_async_result_run_in_thread (res, splice_async_thread, io_priority, cancellable);
1351   g_object_unref (res);
1352 }
1353
1354 static gssize
1355 g_output_stream_real_splice_finish (GOutputStream  *stream,
1356                                     GAsyncResult   *result,
1357                                     GError        **error)
1358 {
1359   GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
1360   SpliceData *op;
1361
1362   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_output_stream_real_splice_async);
1363   op = g_simple_async_result_get_op_res_gpointer (simple);
1364   return op->bytes_copied;
1365 }
1366
1367
1368 static void
1369 flush_async_thread (GSimpleAsyncResult *res,
1370                     GObject            *object,
1371                     GCancellable       *cancellable)
1372 {
1373   GOutputStreamClass *class;
1374   gboolean result;
1375   GError *error = NULL;
1376
1377   class = G_OUTPUT_STREAM_GET_CLASS (object);
1378   result = TRUE;
1379   if (class->flush)
1380     result = class->flush (G_OUTPUT_STREAM (object), cancellable, &error);
1381
1382   if (!result)
1383     {
1384       g_simple_async_result_set_from_error (res, error);
1385       g_error_free (error);
1386     }
1387 }
1388
1389 static void
1390 g_output_stream_real_flush_async (GOutputStream       *stream,
1391                                   int                  io_priority,
1392                                   GCancellable        *cancellable,
1393                                   GAsyncReadyCallback  callback,
1394                                   gpointer             user_data)
1395 {
1396   GSimpleAsyncResult *res;
1397
1398   res = g_simple_async_result_new (G_OBJECT (stream), callback, user_data, g_output_stream_real_write_async);
1399
1400   g_simple_async_result_run_in_thread (res, flush_async_thread, io_priority, cancellable);
1401   g_object_unref (res);
1402 }
1403
1404 static gboolean
1405 g_output_stream_real_flush_finish (GOutputStream  *stream,
1406                                    GAsyncResult   *result,
1407                                    GError        **error)
1408 {
1409   return TRUE;
1410 }
1411
1412 static void
1413 close_async_thread (GSimpleAsyncResult *res,
1414                     GObject            *object,
1415                     GCancellable       *cancellable)
1416 {
1417   GOutputStreamClass *class;
1418   GError *error = NULL;
1419   gboolean result = TRUE;
1420
1421   class = G_OUTPUT_STREAM_GET_CLASS (object);
1422
1423   /* Do a flush here if there is a flush function, and we did not have to do
1424      an async flush before (see g_output_stream_close_async) */
1425   if (class->flush != NULL &&
1426       (class->flush_async == NULL ||
1427        class->flush_async == g_output_stream_real_flush_async))
1428     {
1429       result = class->flush (G_OUTPUT_STREAM (object), cancellable, &error);
1430     }
1431
1432   /* Auto handling of cancelation disabled, and ignore
1433      cancellation, since we want to close things anyway, although
1434      possibly in a quick-n-dirty way. At least we never want to leak
1435      open handles */
1436
1437   if (class->close_fn)
1438     {
1439       /* Make sure to close, even if the flush failed (see sync close) */
1440       if (!result)
1441         class->close_fn (G_OUTPUT_STREAM (object), cancellable, NULL);
1442       else
1443         result = class->close_fn (G_OUTPUT_STREAM (object), cancellable, &error);
1444
1445       if (!result)
1446         {
1447           g_simple_async_result_set_from_error (res, error);
1448           g_error_free (error);
1449         }
1450     }
1451 }
1452
1453 static void
1454 g_output_stream_real_close_async (GOutputStream       *stream,
1455                                   int                  io_priority,
1456                                   GCancellable        *cancellable,
1457                                   GAsyncReadyCallback  callback,
1458                                   gpointer             user_data)
1459 {
1460   GSimpleAsyncResult *res;
1461
1462   res = g_simple_async_result_new (G_OBJECT (stream), callback, user_data, g_output_stream_real_close_async);
1463
1464   g_simple_async_result_set_handle_cancellation (res, FALSE);
1465
1466   g_simple_async_result_run_in_thread (res, close_async_thread, io_priority, cancellable);
1467   g_object_unref (res);
1468 }
1469
1470 static gboolean
1471 g_output_stream_real_close_finish (GOutputStream  *stream,
1472                                    GAsyncResult   *result,
1473                                    GError        **error)
1474 {
1475   GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
1476   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_output_stream_real_close_async);
1477   return TRUE;
1478 }