gio/giostream.c

   1 /* GIO - GLib Input, Output and Streaming Library
   2  *
   3  * Copyright © 2008 codethink
   4  * Copyright © 2009 Red Hat, Inc.
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General
  17  * Public License along with this library; if not, write to the
  18  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  19  * Boston, MA 02111-1307, USA.
  20  *
  21  * Authors: Ryan Lortie <desrt@desrt.ca>
  22  *          Alexander Larsson <alexl@redhat.com>
  23  */
  24
  25 #include "config.h"
  26 #include <glib.h>
  27 #include "glibintl.h"
  28
  29 #include "giostream.h"
  30 #include <gio/gsimpleasyncresult.h>
  31 #include <gio/gasyncresult.h>
  32
  33
  34 G_DEFINE_ABSTRACT_TYPE (GIOStream, g_io_stream, G_TYPE_OBJECT);
  35
  36 /**
  37  * SECTION:giostream
  38  * @short_description: Base class for implementing read/write streams
  39  * @include: gio/gio.h
  40  * @see_also: #GInputStream, #GOutputStream
  41  *
  42  * GIOStream represents an object that has both read and write streams.
  43  * Generally the two streams acts as separate input and output streams,
  44  * but they share some common resources and state. For instance, for
  45  * seekable streams they may use the same position in both streams.
  46  *
  47  * Examples of #GIOStream objects are #GSocketConnection which represents
  48  * a two-way network connection, and #GFileIOStream which represent a
  49  * file handle opened in read-write mode.
  50  *
  51  * To do the actual reading and writing you need to get the substreams
  52  * with g_io_stream_get_input_stream() and g_io_stream_get_output_stream().
  53  *
  54  * The #GIOStream object owns the input and the output streams, not the other
  55  * way around, so keeping the substreams alive will not keep the #GIOStream
  56  * object alive. If the #GIOStream object is freed it will be closed, thus
  57  * closing the substream, so even if the substreams stay alive they will
  58  * always just return a %G_IO_ERROR_CLOSED for all operations.
  59  *
  60  * To close a stream use g_io_stream_close() which will close the common
  61  * stream object and also the individual substreams. You can also close
  62  * the substreams themselves. In most cases this only marks the
  63  * substream as closed, so further I/O on it fails. However, some streams
  64  * may support "half-closed" states where one direction of the stream
  65  * is actually shut down.
  66  *
  67  * Since: 2.22
  68  */
  69
  70 enum
  71 {
  72   PROP_0,
  73   PROP_INPUT_STREAM,
  74   PROP_OUTPUT_STREAM,
  75   PROP_CLOSED
  76 };
  77
  78 struct _GIOStreamPrivate {
  79   guint closed : 1;
  80   guint pending : 1;
  81   GAsyncReadyCallback outstanding_callback;
  82 };
  83
  84 static gboolean g_io_stream_real_close        (GIOStream            *stream,
  85                                                GCancellable         *cancellable,
  86                                                GError              **error);
  87 static void     g_io_stream_real_close_async  (GIOStream            *stream,
  88                                                int                   io_priority,
  89                                                GCancellable         *cancellable,
  90                                                GAsyncReadyCallback   callback,
  91                                                gpointer              user_data);
  92 static gboolean g_io_stream_real_close_finish (GIOStream            *stream,
  93                                                GAsyncResult         *result,
  94                                                GError              **error);
  95
  96 static void
  97 g_io_stream_finalize (GObject *object)
  98 {
  99   G_OBJECT_CLASS (g_io_stream_parent_class)->finalize (object);
 100 }
 101
 102 static void
 103 g_io_stream_dispose (GObject *object)
 104 {
 105   GIOStream *stream;
 106
 107   stream = G_IO_STREAM (object);
 108
 109   if (!stream->priv->closed)
 110     g_io_stream_close (stream, NULL, NULL);
 111
 112   G_OBJECT_CLASS (g_io_stream_parent_class)->dispose (object);
 113 }
 114
 115 static void
 116 g_io_stream_init (GIOStream *stream)
 117 {
 118   stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (stream,
 119                                               G_TYPE_IO_STREAM,
 120                                               GIOStreamPrivate);
 121 }
 122
 123 static void
 124 g_io_stream_get_property (GObject    *object,
 125                           guint       prop_id,
 126                           GValue     *value,
 127                           GParamSpec *pspec)
 128 {
 129   GIOStream *stream = G_IO_STREAM (object);
 130
 131   switch (prop_id)
 132     {
 133       case PROP_CLOSED:
 134         g_value_set_boolean (value, stream->priv->closed);
 135         break;
 136
 137       case PROP_INPUT_STREAM:
 138         g_value_set_object (value, g_io_stream_get_input_stream (stream));
 139         break;
 140
 141       case PROP_OUTPUT_STREAM:
 142         g_value_set_object (value, g_io_stream_get_output_stream (stream));
 143         break;
 144
 145       default:
 146         G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 147     }
 148 }
 149
 150 static void
 151 g_io_stream_class_init (GIOStreamClass *klass)
 152 {
 153   GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
 154
 155   g_type_class_add_private (klass, sizeof (GIOStreamPrivate));
 156
 157   gobject_class->finalize = g_io_stream_finalize;
 158   gobject_class->dispose = g_io_stream_dispose;
 159   gobject_class->get_property = g_io_stream_get_property;
 160
 161   klass->close_fn = g_io_stream_real_close;
 162   klass->close_async = g_io_stream_real_close_async;
 163   klass->close_finish = g_io_stream_real_close_finish;
 164
 165   g_object_class_install_property (gobject_class, PROP_CLOSED,
 166                                    g_param_spec_boolean ("closed",
 167                                                          P_("Closed"),
 168                                                          P_("Is the stream closed"),
 169                                                          FALSE,
 170                                                          G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
 171
 172   g_object_class_install_property (gobject_class, PROP_INPUT_STREAM,
 173                                    g_param_spec_object ("input-stream",
 174                                                         P_("Input stream"),
 175                                                         P_("The GInputStream to read from"),
 176                                                         G_TYPE_INPUT_STREAM,
 177                                                         G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
 178   g_object_class_install_property (gobject_class, PROP_OUTPUT_STREAM,
 179                                    g_param_spec_object ("output-stream",
 180                                                         P_("Output stream"),
 181                                                         P_("The GOutputStream to write to"),
 182                                                         G_TYPE_OUTPUT_STREAM,
 183                                                         G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
 184 }
 185
 186 /**
 187  * g_io_stream_is_closed:
 188  * @stream: a #GIOStream
 189  *
 190  * Checks if a stream is closed.
 191  *
 192  * Returns: %TRUE if the stream is closed.
 193  *
 194  * Since: 2.22
 195  */
 196 gboolean
 197 g_io_stream_is_closed (GIOStream *stream)
 198 {
 199   g_return_val_if_fail (G_IS_IO_STREAM (stream), TRUE);
 200
 201   return stream->priv->closed;
 202 }
 203
 204 /**
 205  * g_io_stream_get_input_stream:
 206  * @stream: a #GIOStream
 207  *
 208  * Gets the input stream for this object. This is used
 209  * for reading.
 210  *
 211  * Returns: (transfer none): a #GInputStream, owned by the #GIOStream.
 212  * Do not free.
 213  *
 214  * Since: 2.22
 215  */
 216 GInputStream *
 217 g_io_stream_get_input_stream (GIOStream *stream)
 218 {
 219   GIOStreamClass *klass;
 220
 221   klass = G_IO_STREAM_GET_CLASS (stream);
 222
 223   g_assert (klass->get_input_stream != NULL);
 224
 225   return klass->get_input_stream (stream);
 226 }
 227
 228 /**
 229  * g_io_stream_get_output_stream:
 230  * @stream: a #GIOStream
 231  *
 232  * Gets the output stream for this object. This is used for
 233  * writing.
 234  *
 235  * Returns: (transfer none): a #GOutputStream, owned by the #GIOStream.
 236  * Do not free.
 237  *
 238  * Since: 2.22
 239  */
 240 GOutputStream *
 241 g_io_stream_get_output_stream (GIOStream *stream)
 242 {
 243   GIOStreamClass *klass;
 244
 245   klass = G_IO_STREAM_GET_CLASS (stream);
 246
 247   g_assert (klass->get_output_stream != NULL);
 248   return klass->get_output_stream (stream);
 249 }
 250
 251 /**
 252  * g_io_stream_has_pending:
 253  * @stream: a #GIOStream
 254  *
 255  * Checks if a stream has pending actions.
 256  *
 257  * Returns: %TRUE if @stream has pending actions.
 258  *
 259  * Since: 2.22
 260  **/
 261 gboolean
 262 g_io_stream_has_pending (GIOStream *stream)
 263 {
 264   g_return_val_if_fail (G_IS_IO_STREAM (stream), FALSE);
 265
 266   return stream->priv->pending;
 267 }
 268
 269 /**
 270  * g_io_stream_set_pending:
 271  * @stream: a #GIOStream
 272  * @error: a #GError location to store the error occurring, or %NULL to
 273  *     ignore
 274  *
 275  * Sets @stream to have actions pending. If the pending flag is
 276  * already set or @stream is closed, it will return %FALSE and set
 277  * @error.
 278  *
 279  * Return value: %TRUE if pending was previously unset and is now set.
 280  *
 281  * Since: 2.22
 282  */
 283 gboolean
 284 g_io_stream_set_pending (GIOStream  *stream,
 285                          GError    **error)
 286 {
 287   g_return_val_if_fail (G_IS_IO_STREAM (stream), FALSE);
 288
 289   if (stream->priv->closed)
 290     {
 291       g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
 292                            _("Stream is already closed"));
 293       return FALSE;
 294     }
 295
 296   if (stream->priv->pending)
 297     {
 298       g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PENDING,
 299                            /* Translators: This is an error you get if there is
 300                             * already an operation running against this stream when
 301                             * you try to start one */
 302                            _("Stream has outstanding operation"));
 303       return FALSE;
 304     }
 305
 306   stream->priv->pending = TRUE;
 307   return TRUE;
 308 }
 309
 310 /**
 311  * g_io_stream_clear_pending:
 312  * @stream: a #GIOStream
 313  *
 314  * Clears the pending flag on @stream.
 315  *
 316  * Since: 2.22
 317  */
 318 void
 319 g_io_stream_clear_pending (GIOStream *stream)
 320 {
 321   g_return_if_fail (G_IS_IO_STREAM (stream));
 322
 323   stream->priv->pending = FALSE;
 324 }
 325
 326 static gboolean
 327 g_io_stream_real_close (GIOStream     *stream,
 328                         GCancellable  *cancellable,
 329                         GError       **error)
 330 {
 331   gboolean res;
 332
 333   res = g_output_stream_close (g_io_stream_get_output_stream (stream),
 334                                cancellable, error);
 335
 336   /* If this errored out, unset error so that we don't report
 337      further errors, but still do the following ops */
 338   if (error != NULL && *error != NULL)
 339     error = NULL;
 340
 341   res &= g_input_stream_close (g_io_stream_get_input_stream (stream),
 342                                cancellable, error);
 343
 344   return res;
 345 }
 346
 347 /**
 348  * g_io_stream_close:
 349  * @stream: a #GIOStream
 350  * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore
 351  * @error: location to store the error occurring, or %NULL to ignore
 352  *
 353  * Closes the stream, releasing resources related to it. This will also
 354  * closes the individual input and output streams, if they are not already
 355  * closed.
 356  *
 357  * Once the stream is closed, all other operations will return
 358  * %G_IO_ERROR_CLOSED. Closing a stream multiple times will not
 359  * return an error.
 360  *
 361  * Closing a stream will automatically flush any outstanding buffers
 362  * in the stream.
 363  *
 364  * Streams will be automatically closed when the last reference
 365  * is dropped, but you might want to call this function to make sure
 366  * resources are released as early as possible.
 367  *
 368  * Some streams might keep the backing store of the stream (e.g. a file
 369  * descriptor) open after the stream is closed. See the documentation for
 370  * the individual stream for details.
 371  *
 372  * On failure the first error that happened will be reported, but the
 373  * close operation will finish as much as possible. A stream that failed
 374  * to close will still return %G_IO_ERROR_CLOSED for all operations.
 375  * Still, it is important to check and report the error to the user,
 376  * otherwise there might be a loss of data as all data might not be written.
 377  *
 378  * If @cancellable is not NULL, then the operation can be cancelled by
 379  * triggering the cancellable object from another thread. If the operation
 380  * was cancelled, the error %G_IO_ERROR_CANCELLED will be returned.
 381  * Cancelling a close will still leave the stream closed, but some streams
 382  * can use a faster close that doesn't block to e.g. check errors.
 383  *
 384  * The default implementation of this method just calls close on the
 385  * individual input/output streams.
 386  *
 387  * Return value: %TRUE on success, %FALSE on failure
 388  *
 389  * Since: 2.22
 390  */
 391 gboolean
 392 g_io_stream_close (GIOStream     *stream,
 393                    GCancellable  *cancellable,
 394                    GError       **error)
 395 {
 396   GIOStreamClass *class;
 397   gboolean res;
 398
 399   g_return_val_if_fail (G_IS_IO_STREAM (stream), FALSE);
 400
 401   class = G_IO_STREAM_GET_CLASS (stream);
 402
 403   if (stream->priv->closed)
 404     return TRUE;
 405
 406   if (!g_io_stream_set_pending (stream, error))
 407     return FALSE;
 408
 409   if (cancellable)
 410     g_cancellable_push_current (cancellable);
 411
 412   res = TRUE;
 413   if (class->close_fn)
 414     res = class->close_fn (stream, cancellable, error);
 415
 416   if (cancellable)
 417     g_cancellable_pop_current (cancellable);
 418
 419   stream->priv->closed = TRUE;
 420   g_io_stream_clear_pending (stream);
 421
 422   return res;
 423 }
 424
 425 static void
 426 async_ready_close_callback_wrapper (GObject      *source_object,
 427                                     GAsyncResult *res,
 428                                     gpointer      user_data)
 429 {
 430   GIOStream *stream = G_IO_STREAM (source_object);
 431
 432   stream->priv->closed = TRUE;
 433   g_io_stream_clear_pending (stream);
 434   if (stream->priv->outstanding_callback)
 435     (*stream->priv->outstanding_callback) (source_object, res, user_data);
 436   g_object_unref (stream);
 437 }
 438
 439 /**
 440  * g_io_stream_close_async:
 441  * @stream: a #GIOStream
 442  * @io_priority: the io priority of the request
 443  * @cancellable: (allow-none): optional cancellable object
 444  * @callback: (scope async): callback to call when the request is satisfied
 445  * @user_data: (closure): the data to pass to callback function
 446  *
 447  * Requests an asynchronous close of the stream, releasing resources
 448  * related to it. When the operation is finished @callback will be
 449  * called. You can then call g_io_stream_close_finish() to get
 450  * the result of the operation.
 451  *
 452  * For behaviour details see g_io_stream_close().
 453  *
 454  * The asynchronous methods have a default fallback that uses threads
 455  * to implement asynchronicity, so they are optional for inheriting
 456  * classes. However, if you override one you must override all.
 457  *
 458  * Since: 2.22
 459  */
 460 void
 461 g_io_stream_close_async (GIOStream           *stream,
 462                          int                  io_priority,
 463                          GCancellable        *cancellable,
 464                          GAsyncReadyCallback  callback,
 465                          gpointer             user_data)
 466 {
 467   GIOStreamClass *class;
 468   GSimpleAsyncResult *simple;
 469   GError *error = NULL;
 470
 471   g_return_if_fail (G_IS_IO_STREAM (stream));
 472
 473   if (stream->priv->closed)
 474     {
 475       simple = g_simple_async_result_new (G_OBJECT (stream),
 476                                           callback,
 477                                           user_data,
 478                                           g_io_stream_close_async);
 479       g_simple_async_result_complete_in_idle (simple);
 480       g_object_unref (simple);
 481       return;
 482     }
 483
 484   if (!g_io_stream_set_pending (stream, &error))
 485     {
 486       g_simple_async_report_take_gerror_in_idle (G_OBJECT (stream),
 487                                             callback,
 488                                             user_data,
 489                                             error);
 490       return;
 491     }
 492
 493   class = G_IO_STREAM_GET_CLASS (stream);
 494   stream->priv->outstanding_callback = callback;
 495   g_object_ref (stream);
 496   class->close_async (stream, io_priority, cancellable,
 497                       async_ready_close_callback_wrapper, user_data);
 498 }
 499
 500 /**
 501  * g_io_stream_close_finish:
 502  * @stream: a #GIOStream
 503  * @result: a #GAsyncResult
 504  * @error: a #GError location to store the error occurring, or %NULL to
 505  *    ignore
 506  *
 507  * Closes a stream.
 508  *
 509  * Returns: %TRUE if stream was successfully closed, %FALSE otherwise.
 510  *
 511  * Since: 2.22
 512  */
 513 gboolean
 514 g_io_stream_close_finish (GIOStream     *stream,
 515                           GAsyncResult  *result,
 516                           GError       **error)
 517 {
 518   GIOStreamClass *class;
 519
 520   g_return_val_if_fail (G_IS_IO_STREAM (stream), FALSE);
 521   g_return_val_if_fail (G_IS_ASYNC_RESULT (result), FALSE);
 522
 523   if (g_async_result_legacy_propagate_error (result, error))
 524     return FALSE;
 525   else if (g_async_result_is_tagged (result, g_io_stream_close_async))
 526     {
 527       /* Special case already closed */
 528       return TRUE;
 529     }
 530
 531   class = G_IO_STREAM_GET_CLASS (stream);
 532   return class->close_finish (stream, result, error);
 533 }
 534
 535
 536 static void
 537 close_async_thread (GSimpleAsyncResult *res,
 538                     GObject            *object,
 539                     GCancellable       *cancellable)
 540 {
 541   GIOStreamClass *class;
 542   GError *error = NULL;
 543   gboolean result;
 544
 545   /* Auto handling of cancelation disabled, and ignore cancellation,
 546    * since we want to close things anyway, although possibly in a
 547    * quick-n-dirty way. At least we never want to leak open handles
 548    */
 549   class = G_IO_STREAM_GET_CLASS (object);
 550   if (class->close_fn)
 551     {
 552       result = class->close_fn (G_IO_STREAM (object), cancellable, &error);
 553       if (!result)
 554         g_simple_async_result_take_error (res, error);
 555     }
 556 }
 557
 558 static void
 559 g_io_stream_real_close_async (GIOStream           *stream,
 560                               int                  io_priority,
 561                               GCancellable        *cancellable,
 562                               GAsyncReadyCallback  callback,
 563                               gpointer             user_data)
 564 {
 565   GSimpleAsyncResult *res;
 566
 567   res = g_simple_async_result_new (G_OBJECT (stream),
 568                                    callback,
 569                                    user_data,
 570                                    g_io_stream_real_close_async);
 571
 572   g_simple_async_result_set_handle_cancellation (res, FALSE);
 573
 574   g_simple_async_result_run_in_thread (res,
 575                                        close_async_thread,
 576                                        io_priority,
 577                                        cancellable);
 578   g_object_unref (res);
 579 }
 580
 581 static gboolean
 582 g_io_stream_real_close_finish (GIOStream     *stream,
 583                                GAsyncResult  *result,
 584                                GError       **error)
 585 {
 586   GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
 587
 588   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) ==
 589                   g_io_stream_real_close_async);
 590
 591   if (g_simple_async_result_propagate_error (simple, error))
 592     return FALSE;
 593
 594   return TRUE;
 595 }
 596
 597 typedef struct
 598 {
 599   GIOStream *stream1;
 600   GIOStream *stream2;
 601   GIOStreamSpliceFlags flags;
 602   gint io_priority;
 603   GCancellable *cancellable;
 604   gulong cancelled_id;
 605   GCancellable *op1_cancellable;
 606   GCancellable *op2_cancellable;
 607   guint completed;
 608   GError *error;
 609 } SpliceContext;
 610
 611 static void
 612 splice_context_free (SpliceContext *ctx)
 613 {
 614   g_object_unref (ctx->stream1);
 615   g_object_unref (ctx->stream2);
 616   if (ctx->cancellable != NULL)
 617     g_object_unref (ctx->cancellable);
 618   g_object_unref (ctx->op1_cancellable);
 619   g_object_unref (ctx->op2_cancellable);
 620   g_clear_error (&ctx->error);
 621   g_slice_free (SpliceContext, ctx);
 622 }
 623
 624 static void
 625 splice_complete (GSimpleAsyncResult *simple,
 626                  SpliceContext      *ctx)
 627 {
 628   if (ctx->cancelled_id != 0)
 629     g_cancellable_disconnect (ctx->cancellable, ctx->cancelled_id);
 630   ctx->cancelled_id = 0;
 631
 632   if (ctx->error != NULL)
 633     g_simple_async_result_set_from_error (simple, ctx->error);
 634   g_simple_async_result_complete (simple);
 635 }
 636
 637 static void
 638 splice_close_cb (GObject      *iostream,
 639                  GAsyncResult *res,
 640                  gpointer      user_data)
 641 {
 642   GSimpleAsyncResult *simple = user_data;
 643   SpliceContext *ctx;
 644   GError *error = NULL;
 645
 646   g_io_stream_close_finish (G_IO_STREAM (iostream), res, &error);
 647
 648   ctx = g_simple_async_result_get_op_res_gpointer (simple);
 649   ctx->completed++;
 650
 651   /* Keep the first error that occurred */
 652   if (error != NULL && ctx->error == NULL)
 653     ctx->error = error;
 654   else
 655     g_clear_error (&error);
 656
 657   /* If all operations are done, complete now */
 658   if (ctx->completed == 4)
 659     splice_complete (simple, ctx);
 660
 661   g_object_unref (simple);
 662 }
 663
 664 static void
 665 splice_cb (GObject      *ostream,
 666            GAsyncResult *res,
 667            gpointer      user_data)
 668 {
 669   GSimpleAsyncResult *simple = user_data;
 670   SpliceContext *ctx;
 671   GError *error = NULL;
 672
 673   g_output_stream_splice_finish (G_OUTPUT_STREAM (ostream), res, &error);
 674
 675   ctx = g_simple_async_result_get_op_res_gpointer (simple);
 676   ctx->completed++;
 677
 678   /* ignore cancellation error if it was not requested by the user */
 679   if (error != NULL &&
 680       g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED) &&
 681       (ctx->cancellable == NULL ||
 682        !g_cancellable_is_cancelled (ctx->cancellable)))
 683     g_clear_error (&error);
 684
 685   /* Keep the first error that occurred */
 686   if (error != NULL && ctx->error == NULL)
 687     ctx->error = error;
 688   else
 689     g_clear_error (&error);
 690
 691    if (ctx->completed == 1 &&
 692        (ctx->flags & G_IO_STREAM_SPLICE_WAIT_FOR_BOTH) == 0)
 693     {
 694       /* We don't want to wait for the 2nd operation to finish, cancel it */
 695       g_cancellable_cancel (ctx->op1_cancellable);
 696       g_cancellable_cancel (ctx->op2_cancellable);
 697     }
 698   else if (ctx->completed == 2)
 699     {
 700       if (ctx->cancellable == NULL ||
 701           !g_cancellable_is_cancelled (ctx->cancellable))
 702         {
 703           g_cancellable_reset (ctx->op1_cancellable);
 704           g_cancellable_reset (ctx->op2_cancellable);
 705         }
 706
 707       /* Close the IO streams if needed */
 708       if ((ctx->flags & G_IO_STREAM_SPLICE_CLOSE_STREAM1) != 0)
 709         g_io_stream_close_async (ctx->stream1, ctx->io_priority,
 710             ctx->op1_cancellable, splice_close_cb, g_object_ref (simple));
 711       else
 712         ctx->completed++;
 713
 714       if ((ctx->flags & G_IO_STREAM_SPLICE_CLOSE_STREAM2) != 0)
 715         g_io_stream_close_async (ctx->stream2, ctx->io_priority,
 716             ctx->op2_cancellable, splice_close_cb, g_object_ref (simple));
 717       else
 718         ctx->completed++;
 719
 720       /* If all operations are done, complete now */
 721       if (ctx->completed == 4)
 722         splice_complete (simple, ctx);
 723     }
 724
 725   g_object_unref (simple);
 726 }
 727
 728 static void
 729 splice_cancelled_cb (GCancellable       *cancellable,
 730                      GSimpleAsyncResult *simple)
 731 {
 732   SpliceContext *ctx;
 733
 734   ctx = g_simple_async_result_get_op_res_gpointer (simple);
 735   g_cancellable_cancel (ctx->op1_cancellable);
 736   g_cancellable_cancel (ctx->op2_cancellable);
 737 }
 738
 739 /**
 740  * g_io_stream_splice_async:
 741  * @stream1: a #GIOStream.
 742  * @stream2: a #GIOStream.
 743  * @flags: a set of #GIOStreamSpliceFlags.
 744  * @io_priority: the io priority of the request.
 745  * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
 746  * @callback: (scope async): a #GAsyncReadyCallback.
 747  * @user_data: (closure): user data passed to @callback.
 748  *
 749  * Asyncronously splice the output stream of @stream1 to the input stream of
 750  * @stream2, and splice the output stream of @stream2 to the input stream of
 751  * @stream1.
 752  *
 753  * When the operation is finished @callback will be called.
 754  * You can then call g_io_stream_splice_finish() to get the
 755  * result of the operation.
 756  *
 757  * Since: 2.28
 758  **/
 759 void
 760 g_io_stream_splice_async (GIOStream            *stream1,
 761                           GIOStream            *stream2,
 762                           GIOStreamSpliceFlags  flags,
 763                           gint                  io_priority,
 764                           GCancellable         *cancellable,
 765                           GAsyncReadyCallback   callback,
 766                           gpointer              user_data)
 767 {
 768   GSimpleAsyncResult *simple;
 769   SpliceContext *ctx;
 770   GInputStream *istream;
 771   GOutputStream *ostream;
 772
 773   if (cancellable != NULL && g_cancellable_is_cancelled (cancellable))
 774     {
 775       g_simple_async_report_error_in_idle (NULL, callback,
 776           user_data, G_IO_ERROR, G_IO_ERROR_CANCELLED,
 777           "Operation has been cancelled");
 778       return;
 779     }
 780
 781   ctx = g_slice_new0 (SpliceContext);
 782   ctx->stream1 = g_object_ref (stream1);
 783   ctx->stream2 = g_object_ref (stream2);
 784   ctx->flags = flags;
 785   ctx->io_priority = io_priority;
 786   ctx->op1_cancellable = g_cancellable_new ();
 787   ctx->op2_cancellable = g_cancellable_new ();
 788   ctx->completed = 0;
 789
 790   simple = g_simple_async_result_new (NULL, callback, user_data,
 791       g_io_stream_splice_finish);
 792   g_simple_async_result_set_op_res_gpointer (simple, ctx,
 793       (GDestroyNotify) splice_context_free);
 794
 795   if (cancellable != NULL)
 796     {
 797       ctx->cancellable = g_object_ref (cancellable);
 798       ctx->cancelled_id = g_cancellable_connect (cancellable,
 799           G_CALLBACK (splice_cancelled_cb), g_object_ref (simple),
 800           g_object_unref);
 801     }
 802
 803   istream = g_io_stream_get_input_stream (stream1);
 804   ostream = g_io_stream_get_output_stream (stream2);
 805   g_output_stream_splice_async (ostream, istream, G_OUTPUT_STREAM_SPLICE_NONE,
 806       io_priority, ctx->op1_cancellable, splice_cb,
 807       g_object_ref (simple));
 808
 809   istream = g_io_stream_get_input_stream (stream2);
 810   ostream = g_io_stream_get_output_stream (stream1);
 811   g_output_stream_splice_async (ostream, istream, G_OUTPUT_STREAM_SPLICE_NONE,
 812       io_priority, ctx->op2_cancellable, splice_cb,
 813       g_object_ref (simple));
 814
 815   g_object_unref (simple);
 816 }
 817
 818 /**
 819  * g_io_stream_splice_finish:
 820  * @result: a #GAsyncResult.
 821  * @error: a #GError location to store the error occurring, or %NULL to
 822  * ignore.
 823  *
 824  * Finishes an asynchronous io stream splice operation.
 825  *
 826  * Returns: %TRUE on success, %FALSE otherwise.
 827  *
 828  * Since: 2.28
 829  **/
 830 gboolean
 831 g_io_stream_splice_finish (GAsyncResult  *result,
 832                            GError       **error)
 833 {
 834   GSimpleAsyncResult *simple;
 835
 836   g_return_val_if_fail (G_IS_SIMPLE_ASYNC_RESULT (result), FALSE);
 837
 838   simple = G_SIMPLE_ASYNC_RESULT (result);
 839
 840   if (g_simple_async_result_propagate_error (simple, error))
 841     return FALSE;
 842
 843   g_return_val_if_fail (g_simple_async_result_is_valid (result, NULL,
 844       g_io_stream_splice_finish), FALSE);
 845
 846   return TRUE;
 847 }