/* GIO - GLib Input, Output and Streaming Library

 * 

 * Copyright (C) 2006-2007 Red Hat, Inc.

 *

 * SPDX-License-Identifier: LGPL-2.1-or-later

 *

 * 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 <gfileinputstream.h>

#include <gseekable.h>

#include "gcancellable.h"

#include "gasyncresult.h"

#include "gtask.h"

#include "gioerror.h"

#include "glibintl.h"

/**

 * GFileInputStream:

 *

 * `GFileInputStream` provides input streams that take their

 * content from a file.

 *

 * `GFileInputStream` implements [iface@Gio.Seekable], 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 [method@Gio.Seekable.tell]. To find out if a file input

 * stream supports seeking, use [vfunc@Gio.Seekable.can_seek].

 * To position a file input stream, use [vfunc@Gio.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: (nullable): 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](iface.AsyncResult.html#io-priority) of the request

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

 * @callback: (scope async): a #GAsyncReadyCallback

 *   to call when the request is satisfied

 * @user_data: 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);

}