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538b2f106d
glib/gio/gfileinputstream.c
Dan Winship 538b2f106d gio: handle GSimpleAsyncResult errors in _finish vmethods 
Originally, the standard idiom with GSimpleAsyncResult was to handle
all errors in the _finish wrapper function, so that vmethods only had
to deal with successful results. But this means that chaining up to a
parent _finish vmethod won't work correctly. Fix this by also checking
for errors in all the relevant vmethods. (We have to redundantly check
in both the vmethod and the wrapper to preserve compatibility.)

https://bugzilla.gnome.org/show_bug.cgi?id=667375
https://bugzilla.gnome.org/show_bug.cgi?id=661767
2012-07-10 10:47:55 -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 <gfileinputstream.h>
#include <gseekable.h>
#include "gsimpleasyncresult.h"
#include "gcancellable.h"
#include "gasyncresult.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);
G_DEFINE_TYPE_WITH_CODE (GFileInputStream, g_file_input_stream, G_TYPE_INPUT_STREAM,
G_IMPLEMENT_INTERFACE (G_TYPE_SEEKABLE,
g_file_input_stream_seekable_iface_init))
struct _GFileInputStreamPrivate {
GAsyncReadyCallback outstanding_callback;
};
static void
g_file_input_stream_class_init (GFileInputStreamClass *klass)
{
g_type_class_add_private (klass, sizeof (GFileInputStreamPrivate));
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_TYPE_INSTANCE_GET_PRIVATE (stream,
G_TYPE_FILE_INPUT_STREAM,
GFileInputStreamPrivate);
}
/**
* 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 <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
*
* 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_simple_async_report_take_gerror_in_idle (G_OBJECT (stream),
callback,
user_data,
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)
{
GSimpleAsyncResult *simple;
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_IS_SIMPLE_ASYNC_RESULT (result))
{
simple = G_SIMPLE_ASYNC_RESULT (result);
if (g_simple_async_result_propagate_error (simple, error))
return NULL;
}
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 *
********************************************/
typedef struct {
char *attributes;
GFileInfo *info;
} QueryInfoAsyncData;
static void
query_info_data_free (QueryInfoAsyncData *data)
{
if (data->info)
g_object_unref (data->info);
g_free (data->attributes);
g_free (data);
}
static void
query_info_async_thread (GSimpleAsyncResult *res,
GObject *object,
GCancellable *cancellable)
{
GFileInputStreamClass *class;
GError *error = NULL;
QueryInfoAsyncData *data;
GFileInfo *info;
data = g_simple_async_result_get_op_res_gpointer (res);
info = NULL;
class = G_FILE_INPUT_STREAM_GET_CLASS (object);
if (class->query_info)
info = class->query_info (G_FILE_INPUT_STREAM (object), data->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_simple_async_result_take_error (res, error);
else
data->info = info;
}
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)
{
GSimpleAsyncResult *res;
QueryInfoAsyncData *data;
data = g_new0 (QueryInfoAsyncData, 1);
data->attributes = g_strdup (attributes);
res = g_simple_async_result_new (G_OBJECT (stream), callback, user_data, g_file_input_stream_real_query_info_async);
g_simple_async_result_set_op_res_gpointer (res, data, (GDestroyNotify)query_info_data_free);
g_simple_async_result_run_in_thread (res, query_info_async_thread, io_priority, cancellable);
g_object_unref (res);
}
static GFileInfo *
g_file_input_stream_real_query_info_finish (GFileInputStream *stream,
GAsyncResult *res,
GError **error)
{
GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (res);
QueryInfoAsyncData *data;
g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_file_input_stream_real_query_info_async);
if (g_simple_async_result_propagate_error (simple, error))
return NULL;
data = g_simple_async_result_get_op_res_gpointer (simple);
if (data->info)
return g_object_ref (data->info);
return NULL;
}
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