/* 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 2.1 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 <gfileoutputstream.h>

#include <gseekable.h>

#include "gasyncresult.h"

#include "gtask.h"

#include "gcancellable.h"

#include "gioerror.h"

#include "glibintl.h"

/**

 * SECTION:gfileoutputstream

 * @short_description: File output streaming operations

 * @include: gio/gio.h

 * @see_also: #GOutputStream, #GDataOutputStream, #GSeekable

 * 

 * GFileOutputStream provides output streams that write their

 * content to a file.

 *

 * GFileOutputStream implements #GSeekable, which allows the output 

 * stream to jump to arbitrary positions in the file and to truncate

 * the file, provided the filesystem of the file supports these 

 * operations.

 *

 * To find the position of a file output stream, use g_seekable_tell().

 * To find out if a file output stream supports seeking, use

 * g_seekable_can_seek().To position a file output stream, use

 * g_seekable_seek(). To find out if a file output stream supports

 * truncating, use g_seekable_can_truncate(). To truncate a file output

 * stream, use g_seekable_truncate().

 **/

static void       g_file_output_stream_seekable_iface_init    (GSeekableIface       *iface);

static goffset    g_file_output_stream_seekable_tell          (GSeekable            *seekable);

static gboolean   g_file_output_stream_seekable_can_seek      (GSeekable            *seekable);

static gboolean   g_file_output_stream_seekable_seek          (GSeekable            *seekable,

							       goffset               offset,

							       GSeekType             type,

							       GCancellable         *cancellable,

							       GError              **error);

static gboolean   g_file_output_stream_seekable_can_truncate  (GSeekable            *seekable);

static gboolean   g_file_output_stream_seekable_truncate      (GSeekable            *seekable,

							       goffset               offset,

							       GCancellable         *cancellable,

							       GError              **error);

static void       g_file_output_stream_real_query_info_async  (GFileOutputStream    *stream,

							       const char           *attributes,

							       int                   io_priority,

							       GCancellable         *cancellable,

							       GAsyncReadyCallback   callback,

							       gpointer              user_data);

static GFileInfo *g_file_output_stream_real_query_info_finish (GFileOutputStream    *stream,

							       GAsyncResult         *result,

							       GError              **error);

struct _GFileOutputStreamPrivate {

  GAsyncReadyCallback outstanding_callback;

};

G_DEFINE_TYPE_WITH_CODE (GFileOutputStream, g_file_output_stream, G_TYPE_OUTPUT_STREAM,

                         G_ADD_PRIVATE (GFileOutputStream)

			 G_IMPLEMENT_INTERFACE (G_TYPE_SEEKABLE,

						g_file_output_stream_seekable_iface_init));

static void

g_file_output_stream_class_init (GFileOutputStreamClass *klass)

{

  klass->query_info_async = g_file_output_stream_real_query_info_async;

  klass->query_info_finish = g_file_output_stream_real_query_info_finish;

}

static void

g_file_output_stream_seekable_iface_init (GSeekableIface *iface)

{

  iface->tell = g_file_output_stream_seekable_tell;

  iface->can_seek = g_file_output_stream_seekable_can_seek;

  iface->seek = g_file_output_stream_seekable_seek;

  iface->can_truncate = g_file_output_stream_seekable_can_truncate;

  iface->truncate_fn = g_file_output_stream_seekable_truncate;

}

static void

g_file_output_stream_init (GFileOutputStream *stream)

{

  stream->priv = g_file_output_stream_get_instance_private (stream);

}

/**

 * g_file_output_stream_query_info:

 * @stream: a #GFileOutputStream.

 * @attributes: a file attribute query string.

 * @cancellable: optional #GCancellable object, %NULL to ignore. 

 * @error: a #GError, %NULL to ignore.

 *

 * Queries a file output stream for the given @attributes. 

 * This function blocks while querying the stream. For the asynchronous 

 * version of this function, see g_file_output_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.

 * 

 * Can fail if the stream was already closed (with @error being set to 

 * %G_IO_ERROR_CLOSED), the stream has pending operations (with @error being

 * set to %G_IO_ERROR_PENDING), or if querying info is not supported for 

 * the stream's interface (with @error being set to %G_IO_ERROR_NOT_SUPPORTED). In

 * all cases of failure, %NULL will be returned.

 * 

 * 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, and %NULL will 

 * be returned. 

 * 

 * Returns: (transfer full): a #GFileInfo for the @stream, or %NULL on error.

 **/

GFileInfo *

g_file_output_stream_query_info (GFileOutputStream      *stream,

				    const char             *attributes,

				    GCancellable           *cancellable,

				    GError                **error)

{

  GFileOutputStreamClass *class;

  GOutputStream *output_stream;

  GFileInfo *info;

  g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), NULL);

  output_stream = G_OUTPUT_STREAM (stream);

  if (!g_output_stream_set_pending (output_stream, error))

    return NULL;

  info = NULL;

  if (cancellable)

    g_cancellable_push_current (cancellable);

  class = G_FILE_OUTPUT_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_output_stream_clear_pending (output_stream);

  return info;

}

static void

async_ready_callback_wrapper (GObject *source_object,

			      GAsyncResult *res,

			      gpointer      user_data)

{

  GFileOutputStream *stream = G_FILE_OUTPUT_STREAM (source_object);

  g_output_stream_clear_pending (G_OUTPUT_STREAM (stream));

  if (stream->priv->outstanding_callback)

    (*stream->priv->outstanding_callback) (source_object, res, user_data);

  g_object_unref (stream);

}

/**

 * g_file_output_stream_query_info_async:

 * @stream: a #GFileOutputStream.

 * @attributes: a file attribute query string.

 * @io_priority: the [I/O priority][gio-GIOScheduler] 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

 * 

 * Asynchronously queries the @stream for a #GFileInfo. When completed,

 * @callback will be called with a #GAsyncResult which can be used to 

 * finish the operation with g_file_output_stream_query_info_finish().

 * 

 * For the synchronous version of this function, see 

 * g_file_output_stream_query_info().

 *

 **/

void

g_file_output_stream_query_info_async (GFileOutputStream     *stream,

					  const char           *attributes,

					  int                   io_priority,

					  GCancellable         *cancellable,

					  GAsyncReadyCallback   callback,

					  gpointer              user_data)

{

  GFileOutputStreamClass *klass;

  GOutputStream *output_stream;

  GError *error = NULL;

  g_return_if_fail (G_IS_FILE_OUTPUT_STREAM (stream));

  output_stream = G_OUTPUT_STREAM (stream);

  if (!g_output_stream_set_pending (output_stream, &error))

    {

      g_task_report_error (stream, callback, user_data,

                           g_file_output_stream_query_info_async,

                           error);

      return;

    }

  klass = G_FILE_OUTPUT_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_output_stream_query_info_finish:

 * @stream: a #GFileOutputStream.

 * @result: a #GAsyncResult.

 * @error: a #GError, %NULL to ignore.

 * 

 * Finalizes the asynchronous query started 

 * by g_file_output_stream_query_info_async().

 * 

 * Returns: (transfer full): A #GFileInfo for the finished query.

 **/

GFileInfo *

g_file_output_stream_query_info_finish (GFileOutputStream     *stream,

					   GAsyncResult         *result,

					   GError              **error)

{

  GFileOutputStreamClass *class;

  g_return_val_if_fail (G_IS_FILE_OUTPUT_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_output_stream_query_info_async))

    return g_task_propagate_pointer (G_TASK (result), error);

  class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);

  return class->query_info_finish (stream, result, error);

}

/**

 * g_file_output_stream_get_etag:

 * @stream: a #GFileOutputStream.

 * 

 * Gets the entity tag for the file when it has been written.

 * This must be called after the stream has been written

 * and closed, as the etag can change while writing.

 * 

 * Returns: the entity tag for the stream.

 **/

char *

g_file_output_stream_get_etag (GFileOutputStream  *stream)

{

  GFileOutputStreamClass *class;

  GOutputStream *output_stream;

  char *etag;

  g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), NULL);

  output_stream = G_OUTPUT_STREAM (stream);

  if (!g_output_stream_is_closed (output_stream))

    {

      g_warning ("stream is not closed yet, can't get etag");

      return NULL;

    }

  etag = NULL;

  class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);

  if (class->get_etag)

    etag = class->get_etag (stream);

  return etag;

}

static goffset

g_file_output_stream_tell (GFileOutputStream  *stream)

{

  GFileOutputStreamClass *class;

  goffset offset;

  g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), 0);  

  class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);

  offset = 0;

  if (class->tell)

    offset = class->tell (stream);

  return offset;

}

static goffset

g_file_output_stream_seekable_tell (GSeekable *seekable)

{

  return g_file_output_stream_tell (G_FILE_OUTPUT_STREAM (seekable));

}

static gboolean

g_file_output_stream_can_seek (GFileOutputStream  *stream)

{

  GFileOutputStreamClass *class;

  gboolean can_seek;

  g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);

  class = G_FILE_OUTPUT_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_output_stream_seekable_can_seek (GSeekable *seekable)

{

  return g_file_output_stream_can_seek (G_FILE_OUTPUT_STREAM (seekable));

}

static gboolean

g_file_output_stream_seek (GFileOutputStream  *stream,

			   goffset             offset,

			   GSeekType           type,

			   GCancellable       *cancellable,

			   GError            **error)

{

  GFileOutputStreamClass *class;

  GOutputStream *output_stream;

  gboolean res;

  g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);

  output_stream = G_OUTPUT_STREAM (stream);

  class = G_FILE_OUTPUT_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_output_stream_set_pending (output_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_output_stream_clear_pending (output_stream);

  return res;

}

static gboolean

g_file_output_stream_seekable_seek (GSeekable  *seekable,

				    goffset     offset,

				    GSeekType   type,

				    GCancellable  *cancellable,

				    GError    **error)

{

  return g_file_output_stream_seek (G_FILE_OUTPUT_STREAM (seekable),

				    offset, type, cancellable, error);

}

static gboolean

g_file_output_stream_can_truncate (GFileOutputStream  *stream)

{

  GFileOutputStreamClass *class;

  gboolean can_truncate;

  g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);

  class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);

  can_truncate = FALSE;

  if (class->truncate_fn)

    {

      can_truncate = TRUE;

      if (class->can_truncate)

	can_truncate = class->can_truncate (stream);

    }

  return can_truncate;

}

static gboolean

g_file_output_stream_seekable_can_truncate (GSeekable  *seekable)

{

  return g_file_output_stream_can_truncate (G_FILE_OUTPUT_STREAM (seekable));

}

static gboolean

g_file_output_stream_truncate (GFileOutputStream  *stream,

			       goffset             size,

			       GCancellable       *cancellable,

			       GError            **error)

{

  GFileOutputStreamClass *class;

  GOutputStream *output_stream;

  gboolean res;

  g_return_val_if_fail (G_IS_FILE_OUTPUT_STREAM (stream), FALSE);

  output_stream = G_OUTPUT_STREAM (stream);

  class = G_FILE_OUTPUT_STREAM_GET_CLASS (stream);

  if (!class->truncate_fn)

    {

      g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,

                           _("Truncate not supported on stream"));

      return FALSE;

    }

  if (!g_output_stream_set_pending (output_stream, error))

    return FALSE;

  if (cancellable)

    g_cancellable_push_current (cancellable);

  res = class->truncate_fn (stream, size, cancellable, error);

  if (cancellable)

    g_cancellable_pop_current (cancellable);

  g_output_stream_clear_pending (output_stream);

  return res;

}

static gboolean

g_file_output_stream_seekable_truncate (GSeekable     *seekable,

					goffset        size,

					GCancellable  *cancellable,

					GError       **error)

{

  return g_file_output_stream_truncate (G_FILE_OUTPUT_STREAM (seekable),

					size, cancellable, error);

}

/********************************************

 *   Default implementation of async ops    *

 ********************************************/

static void

query_info_async_thread (GTask        *task,

                         gpointer      source_object,

                         gpointer      task_data,

                         GCancellable *cancellable)

{

  GFileOutputStream *stream = source_object;

  const char *attributes = task_data;

  GFileOutputStreamClass *class;

  GError *error = NULL;

  GFileInfo *info = NULL;

  class = G_FILE_OUTPUT_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_output_stream_real_query_info_async (GFileOutputStream     *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_output_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_output_stream_real_query_info_finish (GFileOutputStream     *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);

}