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glib/gio/goutputstream.c
Benjamin Otte 482f226270 outputstream: Clarify docs of flush() 
After questioning the semantics of flush on IRC, it seemed necessary to
clarify what flushing is supposed to do. The Linux man page for fflush()
seemed to cover it perfectly, so I just copied it.

I did not add the "via the underlying write mechanism" part as that in
my opinion is not something subclasses should need to guarantee.
2011-12-05 22:40:18 +01:00

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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"
/**
* 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.
*
* 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_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);
}
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;
} WriteData;
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
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_new0 (WriteData, 1);
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, g_free);
op->buffer = buffer;
op->count_requested = count;
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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