/* 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 <string.h>

#include "gpollfilemonitor.h"

#include "gfile.h"

#include "gfilemonitor.h"

#include "gfileinfo.h"

static gboolean g_poll_file_monitor_cancel (GFileMonitor* monitor);

static void schedule_poll_timeout (GPollFileMonitor* poll_monitor);

struct _GPollFileMonitor

{

  GFileMonitor parent_instance;

  GFile *file;

  GFileInfo *last_info;

  GSource *timeout;

};

#define POLL_TIME_SECS 5

#define g_poll_file_monitor_get_type _g_poll_file_monitor_get_type

G_DEFINE_TYPE (GPollFileMonitor, g_poll_file_monitor, G_TYPE_FILE_MONITOR)

static void

g_poll_file_monitor_finalize (GObject* object)

{

  GPollFileMonitor* poll_monitor;

  poll_monitor = G_POLL_FILE_MONITOR (object);

  g_poll_file_monitor_cancel (G_FILE_MONITOR (poll_monitor));

  g_object_unref (poll_monitor->file);

  g_clear_object (&poll_monitor->last_info);

  G_OBJECT_CLASS (g_poll_file_monitor_parent_class)->finalize (object);

}

static void

g_poll_file_monitor_class_init (GPollFileMonitorClass* klass)

{

  GObjectClass* gobject_class = G_OBJECT_CLASS (klass);

  GFileMonitorClass *file_monitor_class = G_FILE_MONITOR_CLASS (klass);

  gobject_class->finalize = g_poll_file_monitor_finalize;

  file_monitor_class->cancel = g_poll_file_monitor_cancel;

}

static void

g_poll_file_monitor_init (GPollFileMonitor* poll_monitor)

{

}

static int

calc_event_type (GFileInfo *last,

		 GFileInfo *new)

{

  if (last == NULL && new == NULL)

    return -1;

  if (last == NULL && new != NULL)

    return G_FILE_MONITOR_EVENT_CREATED;

  if (last != NULL && new == NULL)

    return G_FILE_MONITOR_EVENT_DELETED;

  if (g_strcmp0 (g_file_info_get_etag (last), g_file_info_get_etag (new)))

    return G_FILE_MONITOR_EVENT_CHANGED;

  if (g_file_info_get_size (last) != g_file_info_get_size (new))

    return G_FILE_MONITOR_EVENT_CHANGED;

  return -1;

}

static void

got_new_info (GObject      *source_object,

              GAsyncResult *res,

              gpointer      user_data)

{

  GPollFileMonitor* poll_monitor = user_data;

  GFileInfo *info;

  int event;

  info = g_file_query_info_finish (poll_monitor->file, res, NULL);

  if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)))

    {

      event = calc_event_type (poll_monitor->last_info, info);

      if (event != -1)

	{

	  g_file_monitor_emit_event (G_FILE_MONITOR (poll_monitor),

				     poll_monitor->file,

				     NULL, event);

	  /* We're polling so slowly anyway, so always emit the done hint */

	  if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)) &&

             (event == G_FILE_MONITOR_EVENT_CHANGED || event == G_FILE_MONITOR_EVENT_CREATED))

	    g_file_monitor_emit_event (G_FILE_MONITOR (poll_monitor),

				       poll_monitor->file,

				       NULL, G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT);

	}

      if (poll_monitor->last_info)

	{

	  g_object_unref (poll_monitor->last_info);

	  poll_monitor->last_info = NULL;

	}

      if (info)

	poll_monitor->last_info = g_object_ref (info);

      schedule_poll_timeout (poll_monitor);

    }

  if (info)

    g_object_unref (info);

  g_object_unref (poll_monitor);

}

static gboolean

poll_file_timeout (gpointer data)

{

  GPollFileMonitor* poll_monitor = data;

  g_source_unref (poll_monitor->timeout);

  poll_monitor->timeout = NULL;

  g_file_query_info_async (poll_monitor->file, G_FILE_ATTRIBUTE_ETAG_VALUE "," G_FILE_ATTRIBUTE_STANDARD_SIZE,

			 0, 0, NULL, got_new_info, g_object_ref (poll_monitor));

  return G_SOURCE_REMOVE;

}

static void

schedule_poll_timeout (GPollFileMonitor* poll_monitor)

{

  poll_monitor->timeout = g_timeout_source_new_seconds (POLL_TIME_SECS);

  g_source_set_callback (poll_monitor->timeout, poll_file_timeout, poll_monitor, NULL);

  g_source_attach (poll_monitor->timeout, g_main_context_get_thread_default ());

}

static void

got_initial_info (GObject      *source_object,

                  GAsyncResult *res,

                  gpointer      user_data)

{

  GPollFileMonitor* poll_monitor = user_data;

  GFileInfo *info;

  info = g_file_query_info_finish (poll_monitor->file, res, NULL);

  poll_monitor->last_info = info;

  if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)))

    schedule_poll_timeout (poll_monitor);

  g_object_unref (poll_monitor);

}

/**

 * _g_poll_file_monitor_new:

 * @file: a #GFile.

 * 

 * Polls @file for changes.

 * 

 * Returns: a new #GFileMonitor for the given #GFile. 

 **/

GFileMonitor*

_g_poll_file_monitor_new (GFile *file)

{

  GPollFileMonitor* poll_monitor;

  poll_monitor = g_object_new (G_TYPE_POLL_FILE_MONITOR, NULL);

  poll_monitor->file = g_object_ref (file);

  g_file_query_info_async (file, G_FILE_ATTRIBUTE_ETAG_VALUE "," G_FILE_ATTRIBUTE_STANDARD_SIZE,

			   0, 0, NULL, got_initial_info, g_object_ref (poll_monitor));

  return G_FILE_MONITOR (poll_monitor);

}

static gboolean

g_poll_file_monitor_cancel (GFileMonitor* monitor)

{

  GPollFileMonitor *poll_monitor = G_POLL_FILE_MONITOR (monitor);

  if (poll_monitor->timeout)

    {

      g_source_destroy (poll_monitor->timeout);

      g_source_unref (poll_monitor->timeout);

      poll_monitor->timeout = NULL;

    }

  return TRUE;

}