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