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glib/gio/ginputstream.c
Mike Ruprecht 94a232a4ed GInputStream: Add g_input_stream_async_read_is_via_threads() 
In implementing a better g_output_stream_splice_async() and possibly
other situtations it's helpful to know whether the input stream's
read function internally uses threads. If it and the output stream's
write async functions use threads, then the splice function could
spawn a single thread for better efficiency.

This patch adds a function to determine whether an input stream's
g_input_stream_read_async() function internally uses threads.

https://bugzilla.gnome.org/show_bug.cgi?id=691581
2013-09-29 17:48:40 -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 <glib.h>
#include "glibintl.h"
#include "ginputstream.h"
#include "gioprivate.h"
#include "gseekable.h"
#include "gcancellable.h"
#include "gasyncresult.h"
#include "gioerror.h"
#include "gpollableinputstream.h"
/**
* SECTION:ginputstream
* @short_description: Base class for implementing streaming input
* @include: gio/gio.h
*
* #GInputStream has functions to read from a stream (g_input_stream_read()),
* to close a stream (g_input_stream_close()) and to skip some content
* (g_input_stream_skip()).
*
* 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.
**/
struct _GInputStreamPrivate {
guint closed : 1;
guint pending : 1;
GAsyncReadyCallback outstanding_callback;
};
G_DEFINE_ABSTRACT_TYPE_WITH_PRIVATE (GInputStream, g_input_stream, G_TYPE_OBJECT)
static gssize g_input_stream_real_skip (GInputStream *stream,
gsize count,
GCancellable *cancellable,
GError **error);
static void g_input_stream_real_read_async (GInputStream *stream,
void *buffer,
gsize count,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data);
static gssize g_input_stream_real_read_finish (GInputStream *stream,
GAsyncResult *result,
GError **error);
static void g_input_stream_real_skip_async (GInputStream *stream,
gsize count,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer data);
static gssize g_input_stream_real_skip_finish (GInputStream *stream,
GAsyncResult *result,
GError **error);
static void g_input_stream_real_close_async (GInputStream *stream,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer data);
static gboolean g_input_stream_real_close_finish (GInputStream *stream,
GAsyncResult *result,
GError **error);
static void
g_input_stream_dispose (GObject *object)
{
GInputStream *stream;
stream = G_INPUT_STREAM (object);
if (!stream->priv->closed)
g_input_stream_close (stream, NULL, NULL);
G_OBJECT_CLASS (g_input_stream_parent_class)->dispose (object);
}
static void
g_input_stream_class_init (GInputStreamClass *klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
gobject_class->dispose = g_input_stream_dispose;
klass->skip = g_input_stream_real_skip;
klass->read_async = g_input_stream_real_read_async;
klass->read_finish = g_input_stream_real_read_finish;
klass->skip_async = g_input_stream_real_skip_async;
klass->skip_finish = g_input_stream_real_skip_finish;
klass->close_async = g_input_stream_real_close_async;
klass->close_finish = g_input_stream_real_close_finish;
}
static void
g_input_stream_init (GInputStream *stream)
{
stream->priv = g_input_stream_get_instance_private (stream);
}
/**
* g_input_stream_read:
* @stream: a #GInputStream.
* @buffer: (array length=count) (element-type guint8): a buffer to
* read data into (which should be at least count bytes long).
* @count: the number of bytes that will be read from the stream
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @error: location to store the error occurring, or %NULL to ignore
*
* Tries to read @count bytes from the stream into the buffer starting at
* @buffer. Will block during this read.
*
* If count is zero returns zero 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 read into the buffer is returned.
* It is not an error if this is not the same as the requested size, as it
* can happen e.g. near the end of a file. Zero is returned on end of file
* (or if @count is zero), but never otherwise.
*
* 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 read, or -1 on error, or 0 on end of file.
**/
gssize
g_input_stream_read (GInputStream *stream,
void *buffer,
gsize count,
GCancellable *cancellable,
GError **error)
{
GInputStreamClass *class;
gssize res;
g_return_val_if_fail (G_IS_INPUT_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_INPUT_STREAM_GET_CLASS (stream);
if (class->read_fn == NULL)
{
g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
_("Input stream doesn't implement read"));
return -1;
}
if (!g_input_stream_set_pending (stream, error))
return -1;
if (cancellable)
g_cancellable_push_current (cancellable);
res = class->read_fn (stream, buffer, count, cancellable, error);
if (cancellable)
g_cancellable_pop_current (cancellable);
g_input_stream_clear_pending (stream);
return res;
}
/**
* g_input_stream_read_all:
* @stream: a #GInputStream.
* @buffer: (array length=count) (element-type guint8): a buffer to
* read data into (which should be at least count bytes long).
* @count: the number of bytes that will be read from the stream
* @bytes_read: (out): location to store the number of bytes that was read from the stream
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @error: location to store the error occurring, or %NULL to ignore
*
* Tries to read @count bytes from the stream into the buffer starting at
* @buffer. Will block during this read.
*
* This function is similar to g_input_stream_read(), except it tries to
* read as many bytes as requested, only stopping on an error or end of stream.
*
* On a successful read of @count bytes, or if we reached the end of the
* stream, %TRUE is returned, and @bytes_read is set to the number of bytes
* read into @buffer.
*
* If there is an error during the operation %FALSE is returned and @error
* is set to indicate the error status, @bytes_read is updated to contain
* the number of bytes read into @buffer before the error occurred.
*
* Return value: %TRUE on success, %FALSE if there was an error
**/
gboolean
g_input_stream_read_all (GInputStream *stream,
void *buffer,
gsize count,
gsize *bytes_read,
GCancellable *cancellable,
GError **error)
{
gsize _bytes_read;
gssize res;
g_return_val_if_fail (G_IS_INPUT_STREAM (stream), FALSE);
g_return_val_if_fail (buffer != NULL, FALSE);
_bytes_read = 0;
while (_bytes_read < count)
{
res = g_input_stream_read (stream, (char *)buffer + _bytes_read, count - _bytes_read,
cancellable, error);
if (res == -1)
{
if (bytes_read)
*bytes_read = _bytes_read;
return FALSE;
}
if (res == 0)
break;
_bytes_read += res;
}
if (bytes_read)
*bytes_read = _bytes_read;
return TRUE;
}
/**
* g_input_stream_read_bytes:
* @stream: a #GInputStream.
* @count: maximum number of bytes that will be read from the stream. Common
* values include 4096 and 8192.
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @error: location to store the error occurring, or %NULL to ignore
*
* Like g_input_stream_read(), this tries to read @count bytes from
* the stream in a blocking fashion. However, rather than reading into
* a user-supplied buffer, this will create a new #GBytes containing
* the data that was read. This may be easier to use from language
* bindings.
*
* If count is zero, returns a zero-length #GBytes and does nothing. A
* value of @count larger than %G_MAXSSIZE will cause a
* %G_IO_ERROR_INVALID_ARGUMENT error.
*
* On success, a new #GBytes is returned. It is not an error if the
* size of this object is not the same as the requested size, as it
* can happen e.g. near the end of a file. A zero-length #GBytes is
* returned on end of file (or if @count is zero), but never
* otherwise.
*
* 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 %NULL is returned and @error is set accordingly.
*
* Return value: a new #GBytes, or %NULL on error
**/
GBytes *
g_input_stream_read_bytes (GInputStream *stream,
gsize count,
GCancellable *cancellable,
GError **error)
{
guchar *buf;
gssize nread;
buf = g_malloc (count);
nread = g_input_stream_read (stream, buf, count, cancellable, error);
if (nread == -1)
{
g_free (buf);
return NULL;
}
else if (nread == 0)
{
g_free (buf);
return g_bytes_new_static ("", 0);
}
else
return g_bytes_new_take (buf, nread);
}
/**
* g_input_stream_skip:
* @stream: a #GInputStream.
* @count: the number of bytes that will be skipped from the stream
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @error: location to store the error occurring, or %NULL to ignore
*
* Tries to skip @count bytes from the stream. Will block during the operation.
*
* This is identical to g_input_stream_read(), from a behaviour standpoint,
* but the bytes that are skipped are not returned to the user. Some
* streams have an implementation that is more efficient than reading the data.
*
* This function is optional for inherited classes, as the default implementation
* emulates it using read.
*
* 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.
*
* Return value: Number of bytes skipped, or -1 on error
**/
gssize
g_input_stream_skip (GInputStream *stream,
gsize count,
GCancellable *cancellable,
GError **error)
{
GInputStreamClass *class;
gssize res;
g_return_val_if_fail (G_IS_INPUT_STREAM (stream), -1);
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_INPUT_STREAM_GET_CLASS (stream);
if (!g_input_stream_set_pending (stream, error))
return -1;
if (cancellable)
g_cancellable_push_current (cancellable);
res = class->skip (stream, count, cancellable, error);
if (cancellable)
g_cancellable_pop_current (cancellable);
g_input_stream_clear_pending (stream);
return res;
}
static gssize
g_input_stream_real_skip (GInputStream *stream,
gsize count,
GCancellable *cancellable,
GError **error)
{
GInputStreamClass *class;
gssize ret, read_bytes;
char buffer[8192];
GError *my_error;
if (G_IS_SEEKABLE (stream) && g_seekable_can_seek (G_SEEKABLE (stream)))
{
if (g_seekable_seek (G_SEEKABLE (stream),
count,
G_SEEK_CUR,
cancellable,
NULL))
return count;
}
/* If not seekable, or seek failed, fall back to reading data: */
class = G_INPUT_STREAM_GET_CLASS (stream);
read_bytes = 0;
while (1)
{
my_error = NULL;
ret = class->read_fn (stream, buffer, MIN (sizeof (buffer), count),
cancellable, &my_error);
if (ret == -1)
{
if (read_bytes > 0 &&
my_error->domain == G_IO_ERROR &&
my_error->code == G_IO_ERROR_CANCELLED)
{
g_error_free (my_error);
return read_bytes;
}
g_propagate_error (error, my_error);
return -1;
}
count -= ret;
read_bytes += ret;
if (ret == 0 || count == 0)
return read_bytes;
}
}
/**
* g_input_stream_close:
* @stream: A #GInputStream.
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @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.
*
* 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.
*
* 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 some streams
* can use a faster close that doesn't block to e.g. check errors.
*
* Return value: %TRUE on success, %FALSE on failure
**/
gboolean
g_input_stream_close (GInputStream *stream,
GCancellable *cancellable,
GError **error)
{
GInputStreamClass *class;
gboolean res;
g_return_val_if_fail (G_IS_INPUT_STREAM (stream), FALSE);
class = G_INPUT_STREAM_GET_CLASS (stream);
if (stream->priv->closed)
return TRUE;
res = TRUE;
if (!g_input_stream_set_pending (stream, error))
return FALSE;
if (cancellable)
g_cancellable_push_current (cancellable);
if (class->close_fn)
res = class->close_fn (stream, cancellable, error);
if (cancellable)
g_cancellable_pop_current (cancellable);
g_input_stream_clear_pending (stream);
stream->priv->closed = TRUE;
return res;
}
static void
async_ready_callback_wrapper (GObject *source_object,
GAsyncResult *res,
gpointer user_data)
{
GInputStream *stream = G_INPUT_STREAM (source_object);
g_input_stream_clear_pending (stream);
if (stream->priv->outstanding_callback)
(*stream->priv->outstanding_callback) (source_object, res, user_data);
g_object_unref (stream);
}
static void
async_ready_close_callback_wrapper (GObject *source_object,
GAsyncResult *res,
gpointer user_data)
{
GInputStream *stream = G_INPUT_STREAM (source_object);
g_input_stream_clear_pending (stream);
stream->priv->closed = TRUE;
if (stream->priv->outstanding_callback)
(*stream->priv->outstanding_callback) (source_object, res, user_data);
g_object_unref (stream);
}
/**
* g_input_stream_read_async:
* @stream: A #GInputStream.
* @buffer: (array length=count) (element-type guint8): a buffer to
* read data into (which should be at least count bytes long).
* @count: the number of bytes that will be read from the stream
* @io_priority: the <link linkend="io-priority">I/O priority</link>
* 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 read of @count bytes from the stream into the buffer
* starting at @buffer. When the operation is finished @callback will be called.
* You can then call g_input_stream_read_finish() to get the result of the
* operation.
*
* During an async request no other sync and async calls are allowed on @stream, 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 read into the buffer 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. near the end of a file, but generally we try to read
* as many bytes as requested. Zero is returned on end of file
* (or if @count is zero), but never otherwise.
*
* 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.
**/
void
g_input_stream_read_async (GInputStream *stream,
void *buffer,
gsize count,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GInputStreamClass *class;
GError *error = NULL;
g_return_if_fail (G_IS_INPUT_STREAM (stream));
g_return_if_fail (buffer != NULL);
if (count == 0)
{
GTask *task;
task = g_task_new (stream, cancellable, callback, user_data);
g_task_set_source_tag (task, g_input_stream_read_async);
g_task_return_int (task, 0);
g_object_unref (task);
return;
}
if (((gssize) count) < 0)
{
g_task_report_new_error (stream, callback, user_data,
g_input_stream_read_async,
G_IO_ERROR, G_IO_ERROR_INVALID_ARGUMENT,
_("Too large count value passed to %s"),
G_STRFUNC);
return;
}
if (!g_input_stream_set_pending (stream, &error))
{
g_task_report_error (stream, callback, user_data,
g_input_stream_read_async,
error);
return;
}
class = G_INPUT_STREAM_GET_CLASS (stream);
stream->priv->outstanding_callback = callback;
g_object_ref (stream);
class->read_async (stream, buffer, count, io_priority, cancellable,
async_ready_callback_wrapper, user_data);
}
/**
* g_input_stream_read_finish:
* @stream: a #GInputStream.
* @result: a #GAsyncResult.
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* Finishes an asynchronous stream read operation.
*
* Returns: number of bytes read in, or -1 on error, or 0 on end of file.
**/
gssize
g_input_stream_read_finish (GInputStream *stream,
GAsyncResult *result,
GError **error)
{
GInputStreamClass *class;
g_return_val_if_fail (G_IS_INPUT_STREAM (stream), -1);
g_return_val_if_fail (G_IS_ASYNC_RESULT (result), -1);
if (g_async_result_legacy_propagate_error (result, error))
return -1;
else if (g_async_result_is_tagged (result, g_input_stream_read_async))
return g_task_propagate_int (G_TASK (result), error);
class = G_INPUT_STREAM_GET_CLASS (stream);
return class->read_finish (stream, result, error);
}
static void
read_bytes_callback (GObject *stream,
GAsyncResult *result,
gpointer user_data)
{
GTask *task = user_data;
guchar *buf = g_task_get_task_data (task);
GError *error = NULL;
gssize nread;
GBytes *bytes = NULL;
nread = g_input_stream_read_finish (G_INPUT_STREAM (stream),
result, &error);
if (nread == -1)
{
g_free (buf);
g_task_return_error (task, error);
}
else if (nread == 0)
{
g_free (buf);
bytes = g_bytes_new_static ("", 0);
}
else
bytes = g_bytes_new_take (buf, nread);
if (bytes)
g_task_return_pointer (task, bytes, (GDestroyNotify)g_bytes_unref);
g_object_unref (task);
}
/**
* g_input_stream_read_bytes_async:
* @stream: A #GInputStream.
* @count: the number of bytes that will be read from the stream
* @io_priority: the <link linkend="io-priority">I/O priority</link>
* 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 read of @count bytes from the stream into a
* new #GBytes. When the operation is finished @callback will be
* called. You can then call g_input_stream_read_bytes_finish() to get the
* result of the operation.
*
* During an async request no other sync and async calls are allowed
* on @stream, 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 new #GBytes will be passed to the callback. It is
* not an error if this is smaller than the requested size, as it can
* happen e.g. near the end of a file, but generally we try to read as
* many bytes as requested. Zero is returned on end of file (or if
* @count is zero), but never otherwise.
*
* 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.
**/
void
g_input_stream_read_bytes_async (GInputStream *stream,
gsize count,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GTask *task;
guchar *buf;
task = g_task_new (stream, cancellable, callback, user_data);
buf = g_malloc (count);
g_task_set_task_data (task, buf, NULL);
g_input_stream_read_async (stream, buf, count,
io_priority, cancellable,
read_bytes_callback, task);
}
/**
* g_input_stream_read_bytes_finish:
* @stream: a #GInputStream.
* @result: a #GAsyncResult.
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* Finishes an asynchronous stream read-into-#GBytes operation.
*
* Returns: the newly-allocated #GBytes, or %NULL on error
**/
GBytes *
g_input_stream_read_bytes_finish (GInputStream *stream,
GAsyncResult *result,
GError **error)
{
g_return_val_if_fail (G_IS_INPUT_STREAM (stream), NULL);
g_return_val_if_fail (g_task_is_valid (result, stream), NULL);
return g_task_propagate_pointer (G_TASK (result), error);
}
/**
* g_input_stream_skip_async:
* @stream: A #GInputStream.
* @count: the number of bytes that will be skipped from the stream
* @io_priority: the <link linkend="io-priority">I/O priority</link>
* 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 skip of @count bytes from the stream.
* When the operation is finished @callback will be called.
* You can then call g_input_stream_skip_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 skipped 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. near the end of a file, but generally we try to skip
* as many bytes as requested. Zero is returned on end of file
* (or if @count is zero), but never otherwise.
*
* 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 asynchronous 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_input_stream_skip_async (GInputStream *stream,
gsize count,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GInputStreamClass *class;
GError *error = NULL;
g_return_if_fail (G_IS_INPUT_STREAM (stream));
if (count == 0)
{
GTask *task;
task = g_task_new (stream, cancellable, callback, user_data);
g_task_set_source_tag (task, g_input_stream_skip_async);
g_task_return_int (task, 0);
g_object_unref (task);
return;
}
if (((gssize) count) < 0)
{
g_task_report_new_error (stream, callback, user_data,
g_input_stream_skip_async,
G_IO_ERROR, G_IO_ERROR_INVALID_ARGUMENT,
_("Too large count value passed to %s"),
G_STRFUNC);
return;
}
if (!g_input_stream_set_pending (stream, &error))
{
g_task_report_error (stream, callback, user_data,
g_input_stream_skip_async,
error);
return;
}
class = G_INPUT_STREAM_GET_CLASS (stream);
stream->priv->outstanding_callback = callback;
g_object_ref (stream);
class->skip_async (stream, count, io_priority, cancellable,
async_ready_callback_wrapper, user_data);
}
/**
* g_input_stream_skip_finish:
* @stream: a #GInputStream.
* @result: a #GAsyncResult.
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* Finishes a stream skip operation.
*
* Returns: the size of the bytes skipped, or %-1 on error.
**/
gssize
g_input_stream_skip_finish (GInputStream *stream,
GAsyncResult *result,
GError **error)
{
GInputStreamClass *class;
g_return_val_if_fail (G_IS_INPUT_STREAM (stream), -1);
g_return_val_if_fail (G_IS_ASYNC_RESULT (result), -1);
if (g_async_result_legacy_propagate_error (result, error))
return -1;
else if (g_async_result_is_tagged (result, g_input_stream_skip_async))
return g_task_propagate_int (G_TASK (result), error);
class = G_INPUT_STREAM_GET_CLASS (stream);
return class->skip_finish (stream, result, error);
}
/**
* g_input_stream_close_async:
* @stream: A #GInputStream.
* @io_priority: the <link linkend="io-priority">I/O priority</link>
* 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 closes of the stream, releasing resources related to it.
* When the operation is finished @callback will be called.
* You can then call g_input_stream_close_finish() to get the result of the
* operation.
*
* For behaviour details see g_input_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_input_stream_close_async (GInputStream *stream,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GInputStreamClass *class;
GError *error = NULL;
g_return_if_fail (G_IS_INPUT_STREAM (stream));
if (stream->priv->closed)
{
GTask *task;
task = g_task_new (stream, cancellable, callback, user_data);
g_task_set_source_tag (task, g_input_stream_close_async);
g_task_return_boolean (task, TRUE);
g_object_unref (task);
return;
}
if (!g_input_stream_set_pending (stream, &error))
{
g_task_report_error (stream, callback, user_data,
g_input_stream_close_async,
error);
return;
}
class = G_INPUT_STREAM_GET_CLASS (stream);
stream->priv->outstanding_callback = callback;
g_object_ref (stream);
class->close_async (stream, io_priority, cancellable,
async_ready_close_callback_wrapper, user_data);
}
/**
* g_input_stream_close_finish:
* @stream: a #GInputStream.
* @result: a #GAsyncResult.
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* Finishes closing a stream asynchronously, started from g_input_stream_close_async().
*
* Returns: %TRUE if the stream was closed successfully.
**/
gboolean
g_input_stream_close_finish (GInputStream *stream,
GAsyncResult *result,
GError **error)
{
GInputStreamClass *class;
g_return_val_if_fail (G_IS_INPUT_STREAM (stream), FALSE);
g_return_val_if_fail (G_IS_ASYNC_RESULT (result), FALSE);
if (g_async_result_legacy_propagate_error (result, error))
return FALSE;
else if (g_async_result_is_tagged (result, g_input_stream_close_async))
return g_task_propagate_boolean (G_TASK (result), error);
class = G_INPUT_STREAM_GET_CLASS (stream);
return class->close_finish (stream, result, error);
}
/**
* g_input_stream_is_closed:
* @stream: input stream.
*
* Checks if an input stream is closed.
*
* Returns: %TRUE if the stream is closed.
**/
gboolean
g_input_stream_is_closed (GInputStream *stream)
{
g_return_val_if_fail (G_IS_INPUT_STREAM (stream), TRUE);
return stream->priv->closed;
}
/**
* g_input_stream_has_pending:
* @stream: input stream.
*
* Checks if an input stream has pending actions.
*
* Returns: %TRUE if @stream has pending actions.
**/
gboolean
g_input_stream_has_pending (GInputStream *stream)
{
g_return_val_if_fail (G_IS_INPUT_STREAM (stream), TRUE);
return stream->priv->pending;
}
/**
* g_input_stream_set_pending:
* @stream: input stream
* @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_input_stream_set_pending (GInputStream *stream, GError **error)
{
g_return_val_if_fail (G_IS_INPUT_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_input_stream_clear_pending:
* @stream: input stream
*
* Clears the pending flag on @stream.
**/
void
g_input_stream_clear_pending (GInputStream *stream)
{
g_return_if_fail (G_IS_INPUT_STREAM (stream));
stream->priv->pending = FALSE;
}
/**
* g_input_stream_async_read_is_via_threads:
* @stream: input stream
*
* Checks if an input stream's read_async function uses threads.
*
* Returns: %TRUE if @stream's read_async function uses threads.
**/
gboolean
g_input_stream_async_read_is_via_threads (GInputStream *stream)
{
GInputStreamClass *class;
g_return_val_if_fail (G_IS_INPUT_STREAM (stream), FALSE);
class = G_INPUT_STREAM_GET_CLASS (stream);
return (class->read_async == g_input_stream_real_read_async &&
!(G_IS_POLLABLE_INPUT_STREAM (stream) &&
g_pollable_input_stream_can_poll (G_POLLABLE_INPUT_STREAM (stream))));
}
/********************************************
* Default implementation of async ops *
********************************************/
typedef struct {
void *buffer;
gsize count;
} ReadData;
static void
free_read_data (ReadData *op)
{
g_slice_free (ReadData, op);
}
static void
read_async_thread (GTask *task,
gpointer source_object,
gpointer task_data,
GCancellable *cancellable)
{
GInputStream *stream = source_object;
ReadData *op = task_data;
GInputStreamClass *class;
GError *error = NULL;
gssize nread;
class = G_INPUT_STREAM_GET_CLASS (stream);
nread = class->read_fn (stream,
op->buffer, op->count,
g_task_get_cancellable (task),
&error);
if (nread == -1)
g_task_return_error (task, error);
else
g_task_return_int (task, nread);
}
static void read_async_pollable (GPollableInputStream *stream,
GTask *task);
static gboolean
read_async_pollable_ready (GPollableInputStream *stream,
gpointer user_data)
{
GTask *task = user_data;
read_async_pollable (stream, task);
return FALSE;
}
static void
read_async_pollable (GPollableInputStream *stream,
GTask *task)
{
ReadData *op = g_task_get_task_data (task);
GError *error = NULL;
gssize nread;
if (g_task_return_error_if_cancelled (task))
return;
nread = G_POLLABLE_INPUT_STREAM_GET_INTERFACE (stream)->
read_nonblocking (stream, op->buffer, op->count, &error);
if (g_error_matches (error, G_IO_ERROR, G_IO_ERROR_WOULD_BLOCK))
{
GSource *source;
g_error_free (error);
source = g_pollable_input_stream_create_source (stream,
g_task_get_cancellable (task));
g_task_attach_source (task, source,
(GSourceFunc) read_async_pollable_ready);
g_source_unref (source);
return;
}
if (nread == -1)
g_task_return_error (task, error);
else
g_task_return_int (task, nread);
/* g_input_stream_real_read_async() unrefs task */
}
static void
g_input_stream_real_read_async (GInputStream *stream,
void *buffer,
gsize count,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GTask *task;
ReadData *op;
op = g_slice_new0 (ReadData);
task = g_task_new (stream, cancellable, callback, user_data);
g_task_set_task_data (task, op, (GDestroyNotify) free_read_data);
g_task_set_priority (task, io_priority);
op->buffer = buffer;
op->count = count;
if (!g_input_stream_async_read_is_via_threads (stream))
read_async_pollable (G_POLLABLE_INPUT_STREAM (stream), task);
else
g_task_run_in_thread (task, read_async_thread);
g_object_unref (task);
}
static gssize
g_input_stream_real_read_finish (GInputStream *stream,
GAsyncResult *result,
GError **error)
{
g_return_val_if_fail (g_task_is_valid (result, stream), -1);
return g_task_propagate_int (G_TASK (result), error);
}
static void
skip_async_thread (GTask *task,
gpointer source_object,
gpointer task_data,
GCancellable *cancellable)
{
GInputStream *stream = source_object;
gsize count = GPOINTER_TO_SIZE (task_data);
GInputStreamClass *class;
GError *error = NULL;
gssize ret;
class = G_INPUT_STREAM_GET_CLASS (stream);
ret = class->skip (stream, count,
g_task_get_cancellable (task),
&error);
if (ret == -1)
g_task_return_error (task, error);
else
g_task_return_int (task, ret);
}
typedef struct {
char buffer[8192];
gsize count;
gsize count_skipped;
} SkipFallbackAsyncData;
static void
skip_callback_wrapper (GObject *source_object,
GAsyncResult *res,
gpointer user_data)
{
GInputStreamClass *class;
GTask *task = user_data;
SkipFallbackAsyncData *data = g_task_get_task_data (task);
GError *error = NULL;
gssize ret;
ret = g_input_stream_read_finish (G_INPUT_STREAM (source_object), res, &error);
if (ret > 0)
{
data->count -= ret;
data->count_skipped += ret;
if (data->count > 0)
{
class = G_INPUT_STREAM_GET_CLASS (source_object);
class->read_async (G_INPUT_STREAM (source_object),
data->buffer, MIN (8192, data->count),
g_task_get_priority (task),
g_task_get_cancellable (task),
skip_callback_wrapper, task);
return;
}
}
if (ret == -1 &&
g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED) &&
data->count_skipped)
{
/* No error, return partial read */
g_clear_error (&error);
}
if (error)
g_task_return_error (task, error);
else
g_task_return_int (task, data->count_skipped);
g_object_unref (task);
}
static void
g_input_stream_real_skip_async (GInputStream *stream,
gsize count,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GInputStreamClass *class;
SkipFallbackAsyncData *data;
GTask *task;
class = G_INPUT_STREAM_GET_CLASS (stream);
task = g_task_new (stream, cancellable, callback, user_data);
g_task_set_priority (task, io_priority);
if (g_input_stream_async_read_is_via_threads (stream))
{
/* Read is thread-using async fallback.
* Make skip use threads too, so that we can use a possible sync skip
* implementation. */
g_task_set_task_data (task, GSIZE_TO_POINTER (count), NULL);
g_task_run_in_thread (task, skip_async_thread);
g_object_unref (task);
}
else
{
/* TODO: Skip fallback uses too much memory, should do multiple read calls */
/* There is a custom async read function, lets use that. */
data = g_new (SkipFallbackAsyncData, 1);
data->count = count;
data->count_skipped = 0;
g_task_set_task_data (task, data, g_free);
g_task_set_check_cancellable (task, FALSE);
class->read_async (stream, data->buffer, MIN (8192, count), io_priority, cancellable,
skip_callback_wrapper, task);
}
}
static gssize
g_input_stream_real_skip_finish (GInputStream *stream,
GAsyncResult *result,
GError **error)
{
g_return_val_if_fail (g_task_is_valid (result, stream), -1);
return g_task_propagate_int (G_TASK (result), error);
}
static void
close_async_thread (GTask *task,
gpointer source_object,
gpointer task_data,
GCancellable *cancellable)
{
GInputStream *stream = source_object;
GInputStreamClass *class;
GError *error = NULL;
gboolean result;
class = G_INPUT_STREAM_GET_CLASS (stream);
if (class->close_fn)
{
result = class->close_fn (stream,
g_task_get_cancellable (task),
&error);
if (!result)
{
g_task_return_error (task, error);
return;
}
}
g_task_return_boolean (task, TRUE);
}
static void
g_input_stream_real_close_async (GInputStream *stream,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GTask *task;
task = g_task_new (stream, cancellable, callback, user_data);
g_task_set_check_cancellable (task, FALSE);
g_task_set_priority (task, io_priority);
g_task_run_in_thread (task, close_async_thread);
g_object_unref (task);
}
static gboolean
g_input_stream_real_close_finish (GInputStream *stream,
GAsyncResult *result,
GError **error)
{
g_return_val_if_fail (g_task_is_valid (result, stream), FALSE);
return g_task_propagate_boolean (G_TASK (result), error);
}
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