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glib/gio/gfileinputstream.c
Matthias Clasen a3b0996156 More docs 
svn path=/trunk/; revision=6216
2007-12-30 06:13:12 +00:00

502 lines
15 KiB
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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 "glibintl.h"
#include "gioalias.h"
/**
* SECTION:gfileinputstream
* @short_description: File input streaming operations
* @include: 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. In addition to the generic
* g_seekable_ API, GFileInputStream has its own API for seeking
* and positioning. To find the position of a file input stream,
* use g_file_input_stream_tell(). To find out if a file input
* stream supports seeking, use g_file_input_stream_can_seek().
* To position a file input stream, use g_file_input_stream_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,
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: optional #GCancellable object, %NULL to ignore.
* @error: a #GError location to store the error occuring, or %NULL to
* ignore.
*
* Queries a file input stream the given @attributes.his 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: a #GFileInfo, or %NULL on error.
**/
GFileInfo *
g_file_input_stream_query_info (GFileInputStream *stream,
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 (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: optional #GCancellable object, %NULL to ignore.
* @callback: callback to call when the request is satisfied
* @user_data: the data to pass to callback function
*
* Queries the stream information asynchronously. 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,
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_gerror_in_idle (G_OBJECT (stream),
callback,
user_data,
error);
g_error_free (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 occuring,
* or %NULL to ignore.
*
* Finishes an asynchronous info query operation.
*
* Returns: #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);
}
/**
* g_file_input_stream_tell:
* @stream: a #GFileInputStream.
*
* Gets the current position in the stream.
*
* Returns: a #goffset with the position in the stream.
**/
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));
}
/**
* g_file_input_stream_can_seek:
* @stream: a #GFileInputStream.
*
* Checks if a file input stream can be seeked.
*
* Returns: %TRUE if stream can be seeked. %FALSE otherwise.
**/
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));
}
/**
* g_file_input_stream_seek:
* @stream: a #GFileInputStream.
* @offset: a #goffset to seek.
* @type: a #GSeekType.
* @cancellable: optional #GCancellable object, %NULL to ignore.
* @error: a #GError location to store the error occuring, or
* %NULL to ignore.
*
* Seeks in the file input stream.
*
* 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.
*
* Returns: %TRUE if the stream was successfully seeked to the position.
* %FALSE on error.
**/
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 (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 (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 (&error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
_("Stream doesn't support query_info"));
if (info == NULL)
{
g_simple_async_result_set_from_error (res, error);
g_error_free (error);
}
else
data->info = info;
}
static void
g_file_input_stream_real_query_info_async (GFileInputStream *stream,
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);
data = g_simple_async_result_get_op_res_gpointer (simple);
if (data->info)
return g_object_ref (data->info);
return NULL;
}
#define __G_FILE_INPUT_STREAM_C__
#include "gioaliasdef.c"
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