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glib/gio/goutputstream.c
Dan Winship 800d6ff111 gio: add GBytes-based input/output stream methods 
Using a caller-supplied buffer for g_input_stream_read() doesn't
translate well to the semantics of many other languages, and using a
non-refcounted buffer for read_async() and write_async() makes it
impossible to manage the memory correctly currently in
garbage-collected languages.

Fix both of these issues by adding a new set of methods that work with
GBytes objects rather than plain buffers.

https://bugzilla.gnome.org/show_bug.cgi?id=671139
2012-05-24 17:48:13 -04:00

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/* GIO - GLib Input, Output and Streaming Library
*
* Copyright (C) 2006-2007 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General
* Public License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307, USA.
*
* Author: Alexander Larsson <alexl@redhat.com>
*/
#include "config.h"
#include "goutputstream.h"
#include "gcancellable.h"
#include "gasyncresult.h"
#include "gsimpleasyncresult.h"
#include "ginputstream.h"
#include "gioerror.h"
#include "glibintl.h"
#include "gpollableoutputstream.h"
/**
* SECTION:goutputstream
* @short_description: Base class for implementing streaming output
* @include: gio/gio.h
*
* #GOutputStream has functions to write to a stream (g_output_stream_write()),
* to close a stream (g_output_stream_close()) and to flush pending writes
* (g_output_stream_flush()).
*
* To copy the content of an input stream to an output stream without
* manually handling the reads and writes, use g_output_stream_splice().
*
* All of these functions have async variants too.
**/
G_DEFINE_ABSTRACT_TYPE (GOutputStream, g_output_stream, G_TYPE_OBJECT);
struct _GOutputStreamPrivate {
guint closed : 1;
guint pending : 1;
guint closing : 1;
GAsyncReadyCallback outstanding_callback;
};
static gssize g_output_stream_real_splice (GOutputStream *stream,
GInputStream *source,
GOutputStreamSpliceFlags flags,
GCancellable *cancellable,
GError **error);
static void g_output_stream_real_write_async (GOutputStream *stream,
const void *buffer,
gsize count,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer data);
static gssize g_output_stream_real_write_finish (GOutputStream *stream,
GAsyncResult *result,
GError **error);
static void g_output_stream_real_splice_async (GOutputStream *stream,
GInputStream *source,
GOutputStreamSpliceFlags flags,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer data);
static gssize g_output_stream_real_splice_finish (GOutputStream *stream,
GAsyncResult *result,
GError **error);
static void g_output_stream_real_flush_async (GOutputStream *stream,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer data);
static gboolean g_output_stream_real_flush_finish (GOutputStream *stream,
GAsyncResult *result,
GError **error);
static void g_output_stream_real_close_async (GOutputStream *stream,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer data);
static gboolean g_output_stream_real_close_finish (GOutputStream *stream,
GAsyncResult *result,
GError **error);
static gboolean _g_output_stream_close_internal (GOutputStream *stream,
GCancellable *cancellable,
GError **error);
static void
g_output_stream_finalize (GObject *object)
{
G_OBJECT_CLASS (g_output_stream_parent_class)->finalize (object);
}
static void
g_output_stream_dispose (GObject *object)
{
GOutputStream *stream;
stream = G_OUTPUT_STREAM (object);
if (!stream->priv->closed)
g_output_stream_close (stream, NULL, NULL);
G_OBJECT_CLASS (g_output_stream_parent_class)->dispose (object);
}
static void
g_output_stream_class_init (GOutputStreamClass *klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
g_type_class_add_private (klass, sizeof (GOutputStreamPrivate));
gobject_class->finalize = g_output_stream_finalize;
gobject_class->dispose = g_output_stream_dispose;
klass->splice = g_output_stream_real_splice;
klass->write_async = g_output_stream_real_write_async;
klass->write_finish = g_output_stream_real_write_finish;
klass->splice_async = g_output_stream_real_splice_async;
klass->splice_finish = g_output_stream_real_splice_finish;
klass->flush_async = g_output_stream_real_flush_async;
klass->flush_finish = g_output_stream_real_flush_finish;
klass->close_async = g_output_stream_real_close_async;
klass->close_finish = g_output_stream_real_close_finish;
}
static void
g_output_stream_init (GOutputStream *stream)
{
stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (stream,
G_TYPE_OUTPUT_STREAM,
GOutputStreamPrivate);
}
/**
* g_output_stream_write:
* @stream: a #GOutputStream.
* @buffer: (array length=count) (element-type guint8): the buffer containing the data to write.
* @count: the number of bytes to write
* @cancellable: (allow-none): optional cancellable object
* @error: location to store the error occurring, or %NULL to ignore
*
* Tries to write @count bytes from @buffer into the stream. Will block
* during the operation.
*
* If count is 0, returns 0 and does nothing. A value of @count
* larger than %G_MAXSSIZE will cause a %G_IO_ERROR_INVALID_ARGUMENT error.
*
* On success, the number of bytes written to the stream is returned.
* It is not an error if this is not the same as the requested size, as it
* can happen e.g. on a partial I/O error, or if there is not enough
* storage in the stream. All writes block until at least one byte
* is written or an error occurs; 0 is never returned (unless
* @count is 0).
*
* If @cancellable is not %NULL, then the operation can be cancelled by
* triggering the cancellable object from another thread. If the operation
* was cancelled, the error %G_IO_ERROR_CANCELLED will be returned. If an
* operation was partially finished when the operation was cancelled the
* partial result will be returned, without an error.
*
* On error -1 is returned and @error is set accordingly.
*
* Virtual: write_fn
*
* Return value: Number of bytes written, or -1 on error
**/
gssize
g_output_stream_write (GOutputStream *stream,
const void *buffer,
gsize count,
GCancellable *cancellable,
GError **error)
{
GOutputStreamClass *class;
gssize res;
g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), -1);
g_return_val_if_fail (buffer != NULL, 0);
if (count == 0)
return 0;
if (((gssize) count) < 0)
{
g_set_error (error, G_IO_ERROR, G_IO_ERROR_INVALID_ARGUMENT,
_("Too large count value passed to %s"), G_STRFUNC);
return -1;
}
class = G_OUTPUT_STREAM_GET_CLASS (stream);
if (class->write_fn == NULL)
{
g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
_("Output stream doesn't implement write"));
return -1;
}
if (!g_output_stream_set_pending (stream, error))
return -1;
if (cancellable)
g_cancellable_push_current (cancellable);
res = class->write_fn (stream, buffer, count, cancellable, error);
if (cancellable)
g_cancellable_pop_current (cancellable);
g_output_stream_clear_pending (stream);
return res;
}
/**
* g_output_stream_write_all:
* @stream: a #GOutputStream.
* @buffer: (array length=count) (element-type guint8): the buffer containing the data to write.
* @count: the number of bytes to write
* @bytes_written: (out): location to store the number of bytes that was
* written to the stream
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @error: location to store the error occurring, or %NULL to ignore
*
* Tries to write @count bytes from @buffer into the stream. Will block
* during the operation.
*
* This function is similar to g_output_stream_write(), except it tries to
* write as many bytes as requested, only stopping on an error.
*
* On a successful write of @count bytes, %TRUE is returned, and @bytes_written
* is set to @count.
*
* If there is an error during the operation %FALSE is returned and @error
* is set to indicate the error status, @bytes_written is updated to contain
* the number of bytes written into the stream before the error occurred.
*
* Return value: %TRUE on success, %FALSE if there was an error
**/
gboolean
g_output_stream_write_all (GOutputStream *stream,
const void *buffer,
gsize count,
gsize *bytes_written,
GCancellable *cancellable,
GError **error)
{
gsize _bytes_written;
gssize res;
g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), FALSE);
g_return_val_if_fail (buffer != NULL, FALSE);
_bytes_written = 0;
while (_bytes_written < count)
{
res = g_output_stream_write (stream, (char *)buffer + _bytes_written, count - _bytes_written,
cancellable, error);
if (res == -1)
{
if (bytes_written)
*bytes_written = _bytes_written;
return FALSE;
}
if (res == 0)
g_warning ("Write returned zero without error");
_bytes_written += res;
}
if (bytes_written)
*bytes_written = _bytes_written;
return TRUE;
}
/**
* g_output_stream_write_bytes:
* @stream: a #GOutputStream.
* @bytes: the #GBytes to write
* @cancellable: (allow-none): optional cancellable object
* @error: location to store the error occurring, or %NULL to ignore
*
* Tries to write the data from @bytes into the stream. Will block
* during the operation.
*
* If @bytes is 0-length, returns 0 and does nothing. A #GBytes larger
* than %G_MAXSSIZE will cause a %G_IO_ERROR_INVALID_ARGUMENT error.
*
* On success, the number of bytes written to the stream is returned.
* It is not an error if this is not the same as the requested size, as it
* can happen e.g. on a partial I/O error, or if there is not enough
* storage in the stream. All writes block until at least one byte
* is written or an error occurs; 0 is never returned (unless
* the size of @bytes is 0).
*
* If @cancellable is not %NULL, then the operation can be cancelled by
* triggering the cancellable object from another thread. If the operation
* was cancelled, the error %G_IO_ERROR_CANCELLED will be returned. If an
* operation was partially finished when the operation was cancelled the
* partial result will be returned, without an error.
*
* On error -1 is returned and @error is set accordingly.
*
* Return value: Number of bytes written, or -1 on error
**/
gssize
g_output_stream_write_bytes (GOutputStream *stream,
GBytes *bytes,
GCancellable *cancellable,
GError **error)
{
gsize size;
gconstpointer data;
data = g_bytes_get_data (bytes, &size);
return g_output_stream_write (stream,
data, size,
cancellable,
error);
}
/**
* g_output_stream_flush:
* @stream: a #GOutputStream.
* @cancellable: (allow-none): optional cancellable object
* @error: location to store the error occurring, or %NULL to ignore
*
* Forces a write of all user-space buffered data for the given
* @stream. Will block during the operation. Closing the stream will
* implicitly cause a flush.
*
* This function is optional for inherited classes.
*
* If @cancellable is not %NULL, then the operation can be cancelled by
* triggering the cancellable object from another thread. If the operation
* was cancelled, the error %G_IO_ERROR_CANCELLED will be returned.
*
* Return value: %TRUE on success, %FALSE on error
**/
gboolean
g_output_stream_flush (GOutputStream *stream,
GCancellable *cancellable,
GError **error)
{
GOutputStreamClass *class;
gboolean res;
g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), FALSE);
if (!g_output_stream_set_pending (stream, error))
return FALSE;
class = G_OUTPUT_STREAM_GET_CLASS (stream);
res = TRUE;
if (class->flush)
{
if (cancellable)
g_cancellable_push_current (cancellable);
res = class->flush (stream, cancellable, error);
if (cancellable)
g_cancellable_pop_current (cancellable);
}
g_output_stream_clear_pending (stream);
return res;
}
/**
* g_output_stream_splice:
* @stream: a #GOutputStream.
* @source: a #GInputStream.
* @flags: a set of #GOutputStreamSpliceFlags.
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* Splices an input stream into an output stream.
*
* Returns: a #gssize containing the size of the data spliced, or
* -1 if an error occurred. Note that if the number of bytes
* spliced is greater than %G_MAXSSIZE, then that will be
* returned, and there is no way to determine the actual number
* of bytes spliced.
**/
gssize
g_output_stream_splice (GOutputStream *stream,
GInputStream *source,
GOutputStreamSpliceFlags flags,
GCancellable *cancellable,
GError **error)
{
GOutputStreamClass *class;
gssize bytes_copied;
g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), -1);
g_return_val_if_fail (G_IS_INPUT_STREAM (source), -1);
if (g_input_stream_is_closed (source))
{
g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
_("Source stream is already closed"));
return -1;
}
if (!g_output_stream_set_pending (stream, error))
return -1;
class = G_OUTPUT_STREAM_GET_CLASS (stream);
if (cancellable)
g_cancellable_push_current (cancellable);
bytes_copied = class->splice (stream, source, flags, cancellable, error);
if (cancellable)
g_cancellable_pop_current (cancellable);
g_output_stream_clear_pending (stream);
return bytes_copied;
}
static gssize
g_output_stream_real_splice (GOutputStream *stream,
GInputStream *source,
GOutputStreamSpliceFlags flags,
GCancellable *cancellable,
GError **error)
{
GOutputStreamClass *class = G_OUTPUT_STREAM_GET_CLASS (stream);
gssize n_read, n_written;
gsize bytes_copied;
char buffer[8192], *p;
gboolean res;
bytes_copied = 0;
if (class->write_fn == NULL)
{
g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
_("Output stream doesn't implement write"));
res = FALSE;
goto notsupported;
}
res = TRUE;
do
{
n_read = g_input_stream_read (source, buffer, sizeof (buffer), cancellable, error);
if (n_read == -1)
{
res = FALSE;
break;
}
if (n_read == 0)
break;
p = buffer;
while (n_read > 0)
{
n_written = class->write_fn (stream, p, n_read, cancellable, error);
if (n_written == -1)
{
res = FALSE;
break;
}
p += n_written;
n_read -= n_written;
bytes_copied += n_written;
}
if (bytes_copied > G_MAXSSIZE)
bytes_copied = G_MAXSSIZE;
}
while (res);
notsupported:
if (!res)
error = NULL; /* Ignore further errors */
if (flags & G_OUTPUT_STREAM_SPLICE_CLOSE_SOURCE)
{
/* Don't care about errors in source here */
g_input_stream_close (source, cancellable, NULL);
}
if (flags & G_OUTPUT_STREAM_SPLICE_CLOSE_TARGET)
{
/* But write errors on close are bad! */
res = _g_output_stream_close_internal (stream, cancellable, error);
}
if (res)
return bytes_copied;
return -1;
}
/* Must always be called inside
* g_output_stream_set_pending()/g_output_stream_clear_pending(). */
static gboolean
_g_output_stream_close_internal (GOutputStream *stream,
GCancellable *cancellable,
GError **error)
{
GOutputStreamClass *class;
gboolean res;
if (stream->priv->closed)
return TRUE;
class = G_OUTPUT_STREAM_GET_CLASS (stream);
stream->priv->closing = TRUE;
if (cancellable)
g_cancellable_push_current (cancellable);
if (class->flush)
res = class->flush (stream, cancellable, error);
else
res = TRUE;
if (!res)
{
/* flushing caused the error that we want to return,
* but we still want to close the underlying stream if possible
*/
if (class->close_fn)
class->close_fn (stream, cancellable, NULL);
}
else
{
res = TRUE;
if (class->close_fn)
res = class->close_fn (stream, cancellable, error);
}
if (cancellable)
g_cancellable_pop_current (cancellable);
stream->priv->closing = FALSE;
stream->priv->closed = TRUE;
return res;
}
/**
* g_output_stream_close:
* @stream: A #GOutputStream.
* @cancellable: (allow-none): optional cancellable object
* @error: location to store the error occurring, or %NULL to ignore
*
* Closes the stream, releasing resources related to it.
*
* Once the stream is closed, all other operations will return %G_IO_ERROR_CLOSED.
* Closing a stream multiple times will not return an error.
*
* Closing a stream will automatically flush any outstanding buffers in the
* stream.
*
* Streams will be automatically closed when the last reference
* is dropped, but you might want to call this function to make sure
* resources are released as early as possible.
*
* Some streams might keep the backing store of the stream (e.g. a file descriptor)
* open after the stream is closed. See the documentation for the individual
* stream for details.
*
* On failure the first error that happened will be reported, but the close
* operation will finish as much as possible. A stream that failed to
* close will still return %G_IO_ERROR_CLOSED for all operations. Still, it
* is important to check and report the error to the user, otherwise
* there might be a loss of data as all data might not be written.
*
* If @cancellable is not %NULL, then the operation can be cancelled by
* triggering the cancellable object from another thread. If the operation
* was cancelled, the error %G_IO_ERROR_CANCELLED will be returned.
* Cancelling a close will still leave the stream closed, but there some streams
* can use a faster close that doesn't block to e.g. check errors. On
* cancellation (as with any error) there is no guarantee that all written
* data will reach the target.
*
* Return value: %TRUE on success, %FALSE on failure
**/
gboolean
g_output_stream_close (GOutputStream *stream,
GCancellable *cancellable,
GError **error)
{
gboolean res;
g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), FALSE);
if (stream->priv->closed)
return TRUE;
if (!g_output_stream_set_pending (stream, error))
return FALSE;
res = _g_output_stream_close_internal (stream, cancellable, error);
g_output_stream_clear_pending (stream);
return res;
}
static void
async_ready_callback_wrapper (GObject *source_object,
GAsyncResult *res,
gpointer user_data)
{
GOutputStream *stream = G_OUTPUT_STREAM (source_object);
g_output_stream_clear_pending (stream);
if (stream->priv->outstanding_callback)
(*stream->priv->outstanding_callback) (source_object, res, user_data);
g_object_unref (stream);
}
typedef struct {
gint io_priority;
GCancellable *cancellable;
GError *flush_error;
gpointer user_data;
} CloseUserData;
static void
async_ready_close_callback_wrapper (GObject *source_object,
GAsyncResult *res,
gpointer user_data)
{
GOutputStream *stream = G_OUTPUT_STREAM (source_object);
CloseUserData *data = user_data;
stream->priv->closing = FALSE;
stream->priv->closed = TRUE;
g_output_stream_clear_pending (stream);
if (stream->priv->outstanding_callback)
{
if (data->flush_error != NULL)
{
GSimpleAsyncResult *err;
err = g_simple_async_result_new_take_error (source_object,
stream->priv->outstanding_callback,
data->user_data,
data->flush_error);
data->flush_error = NULL;
(*stream->priv->outstanding_callback) (source_object,
G_ASYNC_RESULT (err),
data->user_data);
g_object_unref (err);
}
else
{
(*stream->priv->outstanding_callback) (source_object,
res,
data->user_data);
}
}
g_object_unref (stream);
if (data->cancellable)
g_object_unref (data->cancellable);
if (data->flush_error)
g_error_free (data->flush_error);
g_slice_free (CloseUserData, data);
}
static void
async_ready_close_flushed_callback_wrapper (GObject *source_object,
GAsyncResult *res,
gpointer user_data)
{
GOutputStream *stream = G_OUTPUT_STREAM (source_object);
GOutputStreamClass *class;
CloseUserData *data = user_data;
GSimpleAsyncResult *simple;
/* propagate the possible error */
if (G_IS_SIMPLE_ASYNC_RESULT (res))
{
simple = G_SIMPLE_ASYNC_RESULT (res);
g_simple_async_result_propagate_error (simple, &data->flush_error);
}
class = G_OUTPUT_STREAM_GET_CLASS (stream);
/* we still close, even if there was a flush error */
class->close_async (stream, data->io_priority, data->cancellable,
async_ready_close_callback_wrapper, user_data);
}
/**
* g_output_stream_write_async:
* @stream: A #GOutputStream.
* @buffer: (array length=count) (element-type guint8): the buffer containing the data to write.
* @count: the number of bytes to write
* @io_priority: the io priority of the request.
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @callback: (scope async): callback to call when the request is satisfied
* @user_data: (closure): the data to pass to callback function
*
* Request an asynchronous write of @count bytes from @buffer into
* the stream. When the operation is finished @callback will be called.
* You can then call g_output_stream_write_finish() to get the result of the
* operation.
*
* During an async request no other sync and async calls are allowed,
* and will result in %G_IO_ERROR_PENDING errors.
*
* A value of @count larger than %G_MAXSSIZE will cause a
* %G_IO_ERROR_INVALID_ARGUMENT error.
*
* On success, the number of bytes written will be passed to the
* @callback. It is not an error if this is not the same as the
* requested size, as it can happen e.g. on a partial I/O error,
* but generally we try to write as many bytes as requested.
*
* You are guaranteed that this method will never fail with
* %G_IO_ERROR_WOULD_BLOCK - if @stream can't accept more data, the
* method will just wait until this changes.
*
* Any outstanding I/O request with higher priority (lower numerical
* value) will be executed before an outstanding request with lower
* priority. Default priority is %G_PRIORITY_DEFAULT.
*
* The asyncronous methods have a default fallback that uses threads
* to implement asynchronicity, so they are optional for inheriting
* classes. However, if you override one you must override all.
*
* For the synchronous, blocking version of this function, see
* g_output_stream_write().
**/
void
g_output_stream_write_async (GOutputStream *stream,
const void *buffer,
gsize count,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GOutputStreamClass *class;
GSimpleAsyncResult *simple;
GError *error = NULL;
g_return_if_fail (G_IS_OUTPUT_STREAM (stream));
g_return_if_fail (buffer != NULL);
if (count == 0)
{
simple = g_simple_async_result_new (G_OBJECT (stream),
callback,
user_data,
g_output_stream_write_async);
g_simple_async_result_complete_in_idle (simple);
g_object_unref (simple);
return;
}
if (((gssize) count) < 0)
{
g_simple_async_report_error_in_idle (G_OBJECT (stream),
callback,
user_data,
G_IO_ERROR, G_IO_ERROR_INVALID_ARGUMENT,
_("Too large count value passed to %s"),
G_STRFUNC);
return;
}
if (!g_output_stream_set_pending (stream, &error))
{
g_simple_async_report_take_gerror_in_idle (G_OBJECT (stream),
callback,
user_data,
error);
return;
}
class = G_OUTPUT_STREAM_GET_CLASS (stream);
stream->priv->outstanding_callback = callback;
g_object_ref (stream);
class->write_async (stream, buffer, count, io_priority, cancellable,
async_ready_callback_wrapper, user_data);
}
/**
* g_output_stream_write_finish:
* @stream: a #GOutputStream.
* @result: a #GAsyncResult.
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* Finishes a stream write operation.
*
* Returns: a #gssize containing the number of bytes written to the stream.
**/
gssize
g_output_stream_write_finish (GOutputStream *stream,
GAsyncResult *result,
GError **error)
{
GSimpleAsyncResult *simple;
GOutputStreamClass *class;
g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), -1);
g_return_val_if_fail (G_IS_ASYNC_RESULT (result), -1);
if (G_IS_SIMPLE_ASYNC_RESULT (result))
{
simple = G_SIMPLE_ASYNC_RESULT (result);
if (g_simple_async_result_propagate_error (simple, error))
return -1;
/* Special case writes of 0 bytes */
if (g_simple_async_result_get_source_tag (simple) == g_output_stream_write_async)
return 0;
}
class = G_OUTPUT_STREAM_GET_CLASS (stream);
return class->write_finish (stream, result, error);
}
static void
write_bytes_callback (GObject *stream,
GAsyncResult *result,
gpointer user_data)
{
GSimpleAsyncResult *simple = user_data;
GError *error = NULL;
gssize nwrote;
nwrote = g_output_stream_write_finish (G_OUTPUT_STREAM (stream),
result, &error);
if (nwrote == -1)
g_simple_async_result_take_error (simple, error);
else
g_simple_async_result_set_op_res_gssize (simple, nwrote);
g_simple_async_result_complete (simple);
g_object_unref (simple);
}
/**
* g_output_stream_write_bytes_async:
* @stream: A #GOutputStream.
* @bytes: The bytes to write
* @io_priority: the io priority of the request.
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @callback: (scope async): callback to call when the request is satisfied
* @user_data: (closure): the data to pass to callback function
*
* Request an asynchronous write of the data in @bytes to the stream.
* When the operation is finished @callback will be called. You can
* then call g_output_stream_write_bytes_finish() to get the result of
* the operation.
*
* During an async request no other sync and async calls are allowed,
* and will result in %G_IO_ERROR_PENDING errors.
*
* A #GBytes larger than %G_MAXSSIZE will cause a
* %G_IO_ERROR_INVALID_ARGUMENT error.
*
* On success, the number of bytes written will be passed to the
* @callback. It is not an error if this is not the same as the
* requested size, as it can happen e.g. on a partial I/O error,
* but generally we try to write as many bytes as requested.
*
* You are guaranteed that this method will never fail with
* %G_IO_ERROR_WOULD_BLOCK - if @stream can't accept more data, the
* method will just wait until this changes.
*
* Any outstanding I/O request with higher priority (lower numerical
* value) will be executed before an outstanding request with lower
* priority. Default priority is %G_PRIORITY_DEFAULT.
*
* For the synchronous, blocking version of this function, see
* g_output_stream_write_bytes().
**/
void
g_output_stream_write_bytes_async (GOutputStream *stream,
GBytes *bytes,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GSimpleAsyncResult *simple;
gsize size;
gconstpointer data;
data = g_bytes_get_data (bytes, &size);
simple = g_simple_async_result_new (G_OBJECT (stream),
callback, user_data,
g_output_stream_write_bytes_async);
g_simple_async_result_set_op_res_gpointer (simple, g_bytes_ref (bytes),
(GDestroyNotify) g_bytes_unref);
g_output_stream_write_async (stream,
data, size,
io_priority,
cancellable,
write_bytes_callback,
simple);
}
/**
* g_output_stream_write_bytes_finish:
* @stream: a #GOutputStream.
* @result: a #GAsyncResult.
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* Finishes a stream write-from-#GBytes operation.
*
* Returns: a #gssize containing the number of bytes written to the stream.
**/
gssize
g_output_stream_write_bytes_finish (GOutputStream *stream,
GAsyncResult *result,
GError **error)
{
GSimpleAsyncResult *simple;
g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), -1);
g_return_val_if_fail (g_simple_async_result_is_valid (result, G_OBJECT (stream), g_output_stream_write_bytes_async), -1);
simple = G_SIMPLE_ASYNC_RESULT (result);
if (g_simple_async_result_propagate_error (simple, error))
return -1;
return g_simple_async_result_get_op_res_gssize (simple);
}
typedef struct {
GInputStream *source;
gpointer user_data;
GAsyncReadyCallback callback;
} SpliceUserData;
static void
async_ready_splice_callback_wrapper (GObject *source_object,
GAsyncResult *res,
gpointer _data)
{
GOutputStream *stream = G_OUTPUT_STREAM (source_object);
SpliceUserData *data = _data;
g_output_stream_clear_pending (stream);
if (data->callback)
(*data->callback) (source_object, res, data->user_data);
g_object_unref (stream);
g_object_unref (data->source);
g_free (data);
}
/**
* g_output_stream_splice_async:
* @stream: a #GOutputStream.
* @source: a #GInputStream.
* @flags: a set of #GOutputStreamSpliceFlags.
* @io_priority: the io priority of the request.
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @callback: (scope async): a #GAsyncReadyCallback.
* @user_data: (closure): user data passed to @callback.
*
* Splices a stream asynchronously.
* When the operation is finished @callback will be called.
* You can then call g_output_stream_splice_finish() to get the
* result of the operation.
*
* For the synchronous, blocking version of this function, see
* g_output_stream_splice().
**/
void
g_output_stream_splice_async (GOutputStream *stream,
GInputStream *source,
GOutputStreamSpliceFlags flags,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GOutputStreamClass *class;
SpliceUserData *data;
GError *error = NULL;
g_return_if_fail (G_IS_OUTPUT_STREAM (stream));
g_return_if_fail (G_IS_INPUT_STREAM (source));
if (g_input_stream_is_closed (source))
{
g_simple_async_report_error_in_idle (G_OBJECT (stream),
callback,
user_data,
G_IO_ERROR, G_IO_ERROR_CLOSED,
_("Source stream is already closed"));
return;
}
if (!g_output_stream_set_pending (stream, &error))
{
g_simple_async_report_take_gerror_in_idle (G_OBJECT (stream),
callback,
user_data,
error);
return;
}
class = G_OUTPUT_STREAM_GET_CLASS (stream);
data = g_new0 (SpliceUserData, 1);
data->callback = callback;
data->user_data = user_data;
data->source = g_object_ref (source);
g_object_ref (stream);
class->splice_async (stream, source, flags, io_priority, cancellable,
async_ready_splice_callback_wrapper, data);
}
/**
* g_output_stream_splice_finish:
* @stream: a #GOutputStream.
* @result: a #GAsyncResult.
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* Finishes an asynchronous stream splice operation.
*
* Returns: a #gssize of the number of bytes spliced. Note that if the
* number of bytes spliced is greater than %G_MAXSSIZE, then that
* will be returned, and there is no way to determine the actual
* number of bytes spliced.
**/
gssize
g_output_stream_splice_finish (GOutputStream *stream,
GAsyncResult *result,
GError **error)
{
GSimpleAsyncResult *simple;
GOutputStreamClass *class;
g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), -1);
g_return_val_if_fail (G_IS_ASYNC_RESULT (result), -1);
if (G_IS_SIMPLE_ASYNC_RESULT (result))
{
simple = G_SIMPLE_ASYNC_RESULT (result);
if (g_simple_async_result_propagate_error (simple, error))
return -1;
}
class = G_OUTPUT_STREAM_GET_CLASS (stream);
return class->splice_finish (stream, result, error);
}
/**
* g_output_stream_flush_async:
* @stream: a #GOutputStream.
* @io_priority: the io priority of the request.
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @callback: (scope async): a #GAsyncReadyCallback to call when the request is satisfied
* @user_data: (closure): the data to pass to callback function
*
* Forces an asynchronous write of all user-space buffered data for
* the given @stream.
* For behaviour details see g_output_stream_flush().
*
* When the operation is finished @callback will be
* called. You can then call g_output_stream_flush_finish() to get the
* result of the operation.
**/
void
g_output_stream_flush_async (GOutputStream *stream,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GOutputStreamClass *class;
GSimpleAsyncResult *simple;
GError *error = NULL;
g_return_if_fail (G_IS_OUTPUT_STREAM (stream));
if (!g_output_stream_set_pending (stream, &error))
{
g_simple_async_report_take_gerror_in_idle (G_OBJECT (stream),
callback,
user_data,
error);
return;
}
stream->priv->outstanding_callback = callback;
g_object_ref (stream);
class = G_OUTPUT_STREAM_GET_CLASS (stream);
if (class->flush_async == NULL)
{
simple = g_simple_async_result_new (G_OBJECT (stream),
async_ready_callback_wrapper,
user_data,
g_output_stream_flush_async);
g_simple_async_result_complete_in_idle (simple);
g_object_unref (simple);
return;
}
class->flush_async (stream, io_priority, cancellable,
async_ready_callback_wrapper, user_data);
}
/**
* g_output_stream_flush_finish:
* @stream: a #GOutputStream.
* @result: a GAsyncResult.
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* Finishes flushing an output stream.
*
* Returns: %TRUE if flush operation succeeded, %FALSE otherwise.
**/
gboolean
g_output_stream_flush_finish (GOutputStream *stream,
GAsyncResult *result,
GError **error)
{
GSimpleAsyncResult *simple;
GOutputStreamClass *klass;
g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), FALSE);
g_return_val_if_fail (G_IS_ASYNC_RESULT (result), FALSE);
if (G_IS_SIMPLE_ASYNC_RESULT (result))
{
simple = G_SIMPLE_ASYNC_RESULT (result);
if (g_simple_async_result_propagate_error (simple, error))
return FALSE;
/* Special case default implementation */
if (g_simple_async_result_get_source_tag (simple) == g_output_stream_flush_async)
return TRUE;
}
klass = G_OUTPUT_STREAM_GET_CLASS (stream);
return klass->flush_finish (stream, result, error);
}
/**
* g_output_stream_close_async:
* @stream: A #GOutputStream.
* @io_priority: the io priority of the request.
* @cancellable: (allow-none): optional cancellable object
* @callback: (scope async): callback to call when the request is satisfied
* @user_data: (closure): the data to pass to callback function
*
* Requests an asynchronous close of the stream, releasing resources
* related to it. When the operation is finished @callback will be
* called. You can then call g_output_stream_close_finish() to get
* the result of the operation.
*
* For behaviour details see g_output_stream_close().
*
* The asyncronous methods have a default fallback that uses threads
* to implement asynchronicity, so they are optional for inheriting
* classes. However, if you override one you must override all.
**/
void
g_output_stream_close_async (GOutputStream *stream,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GOutputStreamClass *class;
GSimpleAsyncResult *simple;
GError *error = NULL;
CloseUserData *data;
g_return_if_fail (G_IS_OUTPUT_STREAM (stream));
if (stream->priv->closed)
{
simple = g_simple_async_result_new (G_OBJECT (stream),
callback,
user_data,
g_output_stream_close_async);
g_simple_async_result_complete_in_idle (simple);
g_object_unref (simple);
return;
}
if (!g_output_stream_set_pending (stream, &error))
{
g_simple_async_report_take_gerror_in_idle (G_OBJECT (stream),
callback,
user_data,
error);
return;
}
class = G_OUTPUT_STREAM_GET_CLASS (stream);
stream->priv->closing = TRUE;
stream->priv->outstanding_callback = callback;
g_object_ref (stream);
data = g_slice_new0 (CloseUserData);
if (cancellable != NULL)
data->cancellable = g_object_ref (cancellable);
data->io_priority = io_priority;
data->user_data = user_data;
/* Call close_async directly if there is no need to flush, or if the flush
can be done sync (in the output stream async close thread) */
if (class->flush_async == NULL ||
(class->flush_async == g_output_stream_real_flush_async &&
(class->flush == NULL || class->close_async == g_output_stream_real_close_async)))
{
class->close_async (stream, io_priority, cancellable,
async_ready_close_callback_wrapper, data);
}
else
{
/* First do an async flush, then do the async close in the callback
wrapper (see async_ready_close_flushed_callback_wrapper) */
class->flush_async (stream, io_priority, cancellable,
async_ready_close_flushed_callback_wrapper, data);
}
}
/**
* g_output_stream_close_finish:
* @stream: a #GOutputStream.
* @result: a #GAsyncResult.
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* Closes an output stream.
*
* Returns: %TRUE if stream was successfully closed, %FALSE otherwise.
**/
gboolean
g_output_stream_close_finish (GOutputStream *stream,
GAsyncResult *result,
GError **error)
{
GSimpleAsyncResult *simple;
GOutputStreamClass *class;
g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), FALSE);
g_return_val_if_fail (G_IS_ASYNC_RESULT (result), FALSE);
if (G_IS_SIMPLE_ASYNC_RESULT (result))
{
simple = G_SIMPLE_ASYNC_RESULT (result);
if (g_simple_async_result_propagate_error (simple, error))
return FALSE;
/* Special case already closed */
if (g_simple_async_result_get_source_tag (simple) == g_output_stream_close_async)
return TRUE;
}
class = G_OUTPUT_STREAM_GET_CLASS (stream);
return class->close_finish (stream, result, error);
}
/**
* g_output_stream_is_closed:
* @stream: a #GOutputStream.
*
* Checks if an output stream has already been closed.
*
* Returns: %TRUE if @stream is closed. %FALSE otherwise.
**/
gboolean
g_output_stream_is_closed (GOutputStream *stream)
{
g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), TRUE);
return stream->priv->closed;
}
/**
* g_output_stream_is_closing:
* @stream: a #GOutputStream.
*
* Checks if an output stream is being closed. This can be
* used inside e.g. a flush implementation to see if the
* flush (or other i/o operation) is called from within
* the closing operation.
*
* Returns: %TRUE if @stream is being closed. %FALSE otherwise.
*
* Since: 2.24
**/
gboolean
g_output_stream_is_closing (GOutputStream *stream)
{
g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), TRUE);
return stream->priv->closing;
}
/**
* g_output_stream_has_pending:
* @stream: a #GOutputStream.
*
* Checks if an ouput stream has pending actions.
*
* Returns: %TRUE if @stream has pending actions.
**/
gboolean
g_output_stream_has_pending (GOutputStream *stream)
{
g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), FALSE);
return stream->priv->pending;
}
/**
* g_output_stream_set_pending:
* @stream: a #GOutputStream.
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* Sets @stream to have actions pending. If the pending flag is
* already set or @stream is closed, it will return %FALSE and set
* @error.
*
* Return value: %TRUE if pending was previously unset and is now set.
**/
gboolean
g_output_stream_set_pending (GOutputStream *stream,
GError **error)
{
g_return_val_if_fail (G_IS_OUTPUT_STREAM (stream), FALSE);
if (stream->priv->closed)
{
g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
_("Stream is already closed"));
return FALSE;
}
if (stream->priv->pending)
{
g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PENDING,
/* Translators: This is an error you get if there is
* already an operation running against this stream when
* you try to start one */
_("Stream has outstanding operation"));
return FALSE;
}
stream->priv->pending = TRUE;
return TRUE;
}
/**
* g_output_stream_clear_pending:
* @stream: output stream
*
* Clears the pending flag on @stream.
**/
void
g_output_stream_clear_pending (GOutputStream *stream)
{
g_return_if_fail (G_IS_OUTPUT_STREAM (stream));
stream->priv->pending = FALSE;
}
/********************************************
* Default implementation of async ops *
********************************************/
typedef struct {
const void *buffer;
gsize count_requested;
gssize count_written;
GCancellable *cancellable;
gint io_priority;
gboolean need_idle;
} WriteData;
static void
free_write_data (WriteData *op)
{
if (op->cancellable)
g_object_unref (op->cancellable);
g_slice_free (WriteData, op);
}
static void
write_async_thread (GSimpleAsyncResult *res,
GObject *object,
GCancellable *cancellable)
{
WriteData *op;
GOutputStreamClass *class;
GError *error = NULL;
class = G_OUTPUT_STREAM_GET_CLASS (object);
op = g_simple_async_result_get_op_res_gpointer (res);
op->count_written = class->write_fn (G_OUTPUT_STREAM (object), op->buffer, op->count_requested,
cancellable, &error);
if (op->count_written == -1)
g_simple_async_result_take_error (res, error);
}
static void write_async_pollable (GPollableOutputStream *stream,
GSimpleAsyncResult *result);
static gboolean
write_async_pollable_ready (GPollableOutputStream *stream,
gpointer user_data)
{
GSimpleAsyncResult *result = user_data;
write_async_pollable (stream, result);
return FALSE;
}
static void
write_async_pollable (GPollableOutputStream *stream,
GSimpleAsyncResult *result)
{
GError *error = NULL;
WriteData *op = g_simple_async_result_get_op_res_gpointer (result);
if (g_cancellable_set_error_if_cancelled (op->cancellable, &error))
op->count_written = -1;
else
{
op->count_written = G_POLLABLE_OUTPUT_STREAM_GET_INTERFACE (stream)->
write_nonblocking (stream, op->buffer, op->count_requested, &error);
}
if (g_error_matches (error, G_IO_ERROR, G_IO_ERROR_WOULD_BLOCK))
{
GSource *source;
g_error_free (error);
op->need_idle = FALSE;
source = g_pollable_output_stream_create_source (stream, op->cancellable);
g_source_set_callback (source,
(GSourceFunc) write_async_pollable_ready,
g_object_ref (result), g_object_unref);
g_source_set_priority (source, op->io_priority);
g_source_attach (source, g_main_context_get_thread_default ());
g_source_unref (source);
return;
}
if (op->count_written == -1)
g_simple_async_result_take_error (result, error);
if (op->need_idle)
g_simple_async_result_complete_in_idle (result);
else
g_simple_async_result_complete (result);
}
static void
g_output_stream_real_write_async (GOutputStream *stream,
const void *buffer,
gsize count,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GSimpleAsyncResult *res;
WriteData *op;
op = g_slice_new0 (WriteData);
res = g_simple_async_result_new (G_OBJECT (stream), callback, user_data, g_output_stream_real_write_async);
g_simple_async_result_set_op_res_gpointer (res, op, (GDestroyNotify) free_write_data);
op->buffer = buffer;
op->count_requested = count;
op->cancellable = cancellable ? g_object_ref (cancellable) : NULL;
op->io_priority = io_priority;
op->need_idle = TRUE;
if (G_IS_POLLABLE_OUTPUT_STREAM (stream) &&
g_pollable_output_stream_can_poll (G_POLLABLE_OUTPUT_STREAM (stream)))
write_async_pollable (G_POLLABLE_OUTPUT_STREAM (stream), res);
else
g_simple_async_result_run_in_thread (res, write_async_thread, io_priority, cancellable);
g_object_unref (res);
}
static gssize
g_output_stream_real_write_finish (GOutputStream *stream,
GAsyncResult *result,
GError **error)
{
GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
WriteData *op;
g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_output_stream_real_write_async);
op = g_simple_async_result_get_op_res_gpointer (simple);
return op->count_written;
}
typedef struct {
GInputStream *source;
GOutputStreamSpliceFlags flags;
gssize bytes_copied;
} SpliceData;
static void
splice_async_thread (GSimpleAsyncResult *result,
GObject *object,
GCancellable *cancellable)
{
SpliceData *op;
GOutputStreamClass *class;
GError *error = NULL;
GOutputStream *stream;
stream = G_OUTPUT_STREAM (object);
class = G_OUTPUT_STREAM_GET_CLASS (object);
op = g_simple_async_result_get_op_res_gpointer (result);
op->bytes_copied = class->splice (stream,
op->source,
op->flags,
cancellable,
&error);
if (op->bytes_copied == -1)
g_simple_async_result_take_error (result, error);
}
static void
g_output_stream_real_splice_async (GOutputStream *stream,
GInputStream *source,
GOutputStreamSpliceFlags flags,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GSimpleAsyncResult *res;
SpliceData *op;
op = g_new0 (SpliceData, 1);
res = g_simple_async_result_new (G_OBJECT (stream), callback, user_data, g_output_stream_real_splice_async);
g_simple_async_result_set_op_res_gpointer (res, op, g_free);
op->flags = flags;
op->source = source;
/* TODO: In the case where both source and destintion have
non-threadbased async calls we can use a true async copy here */
g_simple_async_result_run_in_thread (res, splice_async_thread, io_priority, cancellable);
g_object_unref (res);
}
static gssize
g_output_stream_real_splice_finish (GOutputStream *stream,
GAsyncResult *result,
GError **error)
{
GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
SpliceData *op;
g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_output_stream_real_splice_async);
op = g_simple_async_result_get_op_res_gpointer (simple);
return op->bytes_copied;
}
static void
flush_async_thread (GSimpleAsyncResult *res,
GObject *object,
GCancellable *cancellable)
{
GOutputStreamClass *class;
gboolean result;
GError *error = NULL;
class = G_OUTPUT_STREAM_GET_CLASS (object);
result = TRUE;
if (class->flush)
result = class->flush (G_OUTPUT_STREAM (object), cancellable, &error);
if (!result)
g_simple_async_result_take_error (res, error);
}
static void
g_output_stream_real_flush_async (GOutputStream *stream,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GSimpleAsyncResult *res;
res = g_simple_async_result_new (G_OBJECT (stream), callback, user_data, g_output_stream_real_write_async);
g_simple_async_result_run_in_thread (res, flush_async_thread, io_priority, cancellable);
g_object_unref (res);
}
static gboolean
g_output_stream_real_flush_finish (GOutputStream *stream,
GAsyncResult *result,
GError **error)
{
return TRUE;
}
static void
close_async_thread (GSimpleAsyncResult *res,
GObject *object,
GCancellable *cancellable)
{
GOutputStreamClass *class;
GError *error = NULL;
gboolean result = TRUE;
class = G_OUTPUT_STREAM_GET_CLASS (object);
/* Do a flush here if there is a flush function, and we did not have to do
an async flush before (see g_output_stream_close_async) */
if (class->flush != NULL &&
(class->flush_async == NULL ||
class->flush_async == g_output_stream_real_flush_async))
{
result = class->flush (G_OUTPUT_STREAM (object), cancellable, &error);
}
/* Auto handling of cancelation disabled, and ignore
cancellation, since we want to close things anyway, although
possibly in a quick-n-dirty way. At least we never want to leak
open handles */
if (class->close_fn)
{
/* Make sure to close, even if the flush failed (see sync close) */
if (!result)
class->close_fn (G_OUTPUT_STREAM (object), cancellable, NULL);
else
result = class->close_fn (G_OUTPUT_STREAM (object), cancellable, &error);
if (!result)
g_simple_async_result_take_error (res, error);
}
}
static void
g_output_stream_real_close_async (GOutputStream *stream,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GSimpleAsyncResult *res;
res = g_simple_async_result_new (G_OBJECT (stream), callback, user_data, g_output_stream_real_close_async);
g_simple_async_result_set_handle_cancellation (res, FALSE);
g_simple_async_result_run_in_thread (res, close_async_thread, io_priority, cancellable);
g_object_unref (res);
}
static gboolean
g_output_stream_real_close_finish (GOutputStream *stream,
GAsyncResult *result,
GError **error)
{
GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_output_stream_real_close_async);
return TRUE;
}
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