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glib/gio/gfileinputstream.c
Philip Withnall 3613b7a366 gio: Add source tags to various GTasks constructed in GLib 
This makes them easier to identify when debugging and profiling.

This patch was somewhat less than interesting to write.

https://bugzilla.gnome.org/show_bug.cgi?id=767765
2016-06-29 15:16:52 +01:00

430 lines
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C
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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, see <http://www.gnu.org/licenses/>.
*
* Author: Alexander Larsson <alexl@redhat.com>
*/
#include "config.h"
#include <glib.h>
#include <gfileinputstream.h>
#include <gseekable.h>
#include "gcancellable.h"
#include "gasyncresult.h"
#include "gtask.h"
#include "gioerror.h"
#include "glibintl.h"
/**
* SECTION:gfileinputstream
* @short_description: File input streaming operations
* @include: gio/gio.h
* @see_also: #GInputStream, #GDataInputStream, #GSeekable
*
* GFileInputStream provides input streams that take their
* content from a file.
*
* GFileInputStream implements #GSeekable, which allows the input
* stream to jump to arbitrary positions in the file, provided the
* filesystem of the file allows it. To find the position of a file
* input stream, use g_seekable_tell(). To find out if a file input
* stream supports seeking, use g_seekable_can_seek().
* To position a file input stream, use g_seekable_seek().
**/
static void g_file_input_stream_seekable_iface_init (GSeekableIface *iface);
static goffset g_file_input_stream_seekable_tell (GSeekable *seekable);
static gboolean g_file_input_stream_seekable_can_seek (GSeekable *seekable);
static gboolean g_file_input_stream_seekable_seek (GSeekable *seekable,
goffset offset,
GSeekType type,
GCancellable *cancellable,
GError **error);
static gboolean g_file_input_stream_seekable_can_truncate (GSeekable *seekable);
static gboolean g_file_input_stream_seekable_truncate (GSeekable *seekable,
goffset offset,
GCancellable *cancellable,
GError **error);
static void g_file_input_stream_real_query_info_async (GFileInputStream *stream,
const char *attributes,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data);
static GFileInfo *g_file_input_stream_real_query_info_finish (GFileInputStream *stream,
GAsyncResult *result,
GError **error);
struct _GFileInputStreamPrivate {
GAsyncReadyCallback outstanding_callback;
};
G_DEFINE_TYPE_WITH_CODE (GFileInputStream, g_file_input_stream, G_TYPE_INPUT_STREAM,
G_ADD_PRIVATE (GFileInputStream)
G_IMPLEMENT_INTERFACE (G_TYPE_SEEKABLE,
g_file_input_stream_seekable_iface_init))
static void
g_file_input_stream_class_init (GFileInputStreamClass *klass)
{
klass->query_info_async = g_file_input_stream_real_query_info_async;
klass->query_info_finish = g_file_input_stream_real_query_info_finish;
}
static void
g_file_input_stream_seekable_iface_init (GSeekableIface *iface)
{
iface->tell = g_file_input_stream_seekable_tell;
iface->can_seek = g_file_input_stream_seekable_can_seek;
iface->seek = g_file_input_stream_seekable_seek;
iface->can_truncate = g_file_input_stream_seekable_can_truncate;
iface->truncate_fn = g_file_input_stream_seekable_truncate;
}
static void
g_file_input_stream_init (GFileInputStream *stream)
{
stream->priv = g_file_input_stream_get_instance_private (stream);
}
/**
* g_file_input_stream_query_info:
* @stream: a #GFileInputStream.
* @attributes: a file attribute query string.
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* Queries a file input stream the given @attributes. This function blocks
* while querying the stream. For the asynchronous (non-blocking) version
* of this function, see g_file_input_stream_query_info_async(). While the
* stream is blocked, the stream will set the pending flag internally, and
* any other operations on the stream will fail with %G_IO_ERROR_PENDING.
*
* Returns: (transfer full): a #GFileInfo, or %NULL on error.
**/
GFileInfo *
g_file_input_stream_query_info (GFileInputStream *stream,
const char *attributes,
GCancellable *cancellable,
GError **error)
{
GFileInputStreamClass *class;
GInputStream *input_stream;
GFileInfo *info;
g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), NULL);
input_stream = G_INPUT_STREAM (stream);
if (!g_input_stream_set_pending (input_stream, error))
return NULL;
info = NULL;
if (cancellable)
g_cancellable_push_current (cancellable);
class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
if (class->query_info)
info = class->query_info (stream, attributes, cancellable, error);
else
g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
_("Stream doesn't support query_info"));
if (cancellable)
g_cancellable_pop_current (cancellable);
g_input_stream_clear_pending (input_stream);
return info;
}
static void
async_ready_callback_wrapper (GObject *source_object,
GAsyncResult *res,
gpointer user_data)
{
GFileInputStream *stream = G_FILE_INPUT_STREAM (source_object);
g_input_stream_clear_pending (G_INPUT_STREAM (stream));
if (stream->priv->outstanding_callback)
(*stream->priv->outstanding_callback) (source_object, res, user_data);
g_object_unref (stream);
}
/**
* g_file_input_stream_query_info_async:
* @stream: a #GFileInputStream.
* @attributes: a file attribute query string.
* @io_priority: the [I/O priority][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
*
* Queries the stream information asynchronously.
* When the operation is finished @callback will be called.
* You can then call g_file_input_stream_query_info_finish()
* to get the result of the operation.
*
* For the synchronous version of this function,
* see g_file_input_stream_query_info().
*
* 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 set
*
**/
void
g_file_input_stream_query_info_async (GFileInputStream *stream,
const char *attributes,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GFileInputStreamClass *klass;
GInputStream *input_stream;
GError *error = NULL;
g_return_if_fail (G_IS_FILE_INPUT_STREAM (stream));
input_stream = G_INPUT_STREAM (stream);
if (!g_input_stream_set_pending (input_stream, &error))
{
g_task_report_error (stream, callback, user_data,
g_file_input_stream_query_info_async,
error);
return;
}
klass = G_FILE_INPUT_STREAM_GET_CLASS (stream);
stream->priv->outstanding_callback = callback;
g_object_ref (stream);
klass->query_info_async (stream, attributes, io_priority, cancellable,
async_ready_callback_wrapper, user_data);
}
/**
* g_file_input_stream_query_info_finish:
* @stream: a #GFileInputStream.
* @result: a #GAsyncResult.
* @error: a #GError location to store the error occurring,
* or %NULL to ignore.
*
* Finishes an asynchronous info query operation.
*
* Returns: (transfer full): #GFileInfo.
**/
GFileInfo *
g_file_input_stream_query_info_finish (GFileInputStream *stream,
GAsyncResult *result,
GError **error)
{
GFileInputStreamClass *class;
g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), NULL);
g_return_val_if_fail (G_IS_ASYNC_RESULT (result), NULL);
if (g_async_result_legacy_propagate_error (result, error))
return NULL;
else if (g_async_result_is_tagged (result, g_file_input_stream_query_info_async))
return g_task_propagate_pointer (G_TASK (result), error);
class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
return class->query_info_finish (stream, result, error);
}
static goffset
g_file_input_stream_tell (GFileInputStream *stream)
{
GFileInputStreamClass *class;
goffset offset;
g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), 0);
class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
offset = 0;
if (class->tell)
offset = class->tell (stream);
return offset;
}
static goffset
g_file_input_stream_seekable_tell (GSeekable *seekable)
{
return g_file_input_stream_tell (G_FILE_INPUT_STREAM (seekable));
}
static gboolean
g_file_input_stream_can_seek (GFileInputStream *stream)
{
GFileInputStreamClass *class;
gboolean can_seek;
g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), FALSE);
class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
can_seek = FALSE;
if (class->seek)
{
can_seek = TRUE;
if (class->can_seek)
can_seek = class->can_seek (stream);
}
return can_seek;
}
static gboolean
g_file_input_stream_seekable_can_seek (GSeekable *seekable)
{
return g_file_input_stream_can_seek (G_FILE_INPUT_STREAM (seekable));
}
static gboolean
g_file_input_stream_seek (GFileInputStream *stream,
goffset offset,
GSeekType type,
GCancellable *cancellable,
GError **error)
{
GFileInputStreamClass *class;
GInputStream *input_stream;
gboolean res;
g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), FALSE);
input_stream = G_INPUT_STREAM (stream);
class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
if (!class->seek)
{
g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
_("Seek not supported on stream"));
return FALSE;
}
if (!g_input_stream_set_pending (input_stream, error))
return FALSE;
if (cancellable)
g_cancellable_push_current (cancellable);
res = class->seek (stream, offset, type, cancellable, error);
if (cancellable)
g_cancellable_pop_current (cancellable);
g_input_stream_clear_pending (input_stream);
return res;
}
static gboolean
g_file_input_stream_seekable_seek (GSeekable *seekable,
goffset offset,
GSeekType type,
GCancellable *cancellable,
GError **error)
{
return g_file_input_stream_seek (G_FILE_INPUT_STREAM (seekable),
offset, type, cancellable, error);
}
static gboolean
g_file_input_stream_seekable_can_truncate (GSeekable *seekable)
{
return FALSE;
}
static gboolean
g_file_input_stream_seekable_truncate (GSeekable *seekable,
goffset offset,
GCancellable *cancellable,
GError **error)
{
g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
_("Truncate not allowed on input stream"));
return FALSE;
}
/********************************************
* Default implementation of async ops *
********************************************/
static void
query_info_async_thread (GTask *task,
gpointer source_object,
gpointer task_data,
GCancellable *cancellable)
{
GFileInputStream *stream = source_object;
const char *attributes = task_data;
GFileInputStreamClass *class;
GError *error = NULL;
GFileInfo *info = NULL;
class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
if (class->query_info)
info = class->query_info (stream, attributes, cancellable, &error);
else
g_set_error_literal (&error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
_("Stream doesn't support query_info"));
if (info == NULL)
g_task_return_error (task, error);
else
g_task_return_pointer (task, info, g_object_unref);
}
static void
g_file_input_stream_real_query_info_async (GFileInputStream *stream,
const char *attributes,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GTask *task;
task = g_task_new (stream, cancellable, callback, user_data);
g_task_set_source_tag (task, g_file_input_stream_real_query_info_async);
g_task_set_task_data (task, g_strdup (attributes), g_free);
g_task_set_priority (task, io_priority);
g_task_run_in_thread (task, query_info_async_thread);
g_object_unref (task);
}
static GFileInfo *
g_file_input_stream_real_query_info_finish (GFileInputStream *stream,
GAsyncResult *res,
GError **error)
{
g_return_val_if_fail (g_task_is_valid (res, stream), NULL);
return g_task_propagate_pointer (G_TASK (res), error);
}
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