/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*-

   nautilus-clipboard-monitor.c: catch clipboard changes.
    
   Copyright (C) 2004 Red Hat, Inc.
  
   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.
  
   This program 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
   General Public License for more details.
  
   You should have received a copy of the GNU General Public
   License along with this program; 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 "nautilus-clipboard-monitor.h"

#include <eel/eel-debug.h>
#include <eel/eel-gtk-macros.h>
#include <eel/eel-glib-extensions.h>
#include <eel/eel-glib-extensions.h>
#include <gtk/gtk.h>

/* X11 has a weakness when it comes to clipboard handling,
 * there is no way to get told when the owner of the clipboard
 * changes. This is often needed, for instance to set the
 * sensitivity of the paste menu item. We work around this
 * internally in an app by telling the clipboard monitor when
 * we changed the clipboard. Unfortunately this doesn't give
 * us perfect results, we still don't catch changes made by
 * other clients
 *
 * This is fixed with the XFIXES extensions, which recent versions
 * of Gtk+ supports as the owner_change signal on GtkClipboard. We
 * use this now, but keep the old code since not all X servers support
 * XFIXES.
 */

enum {
	CLIPBOARD_CHANGED,
	LAST_SIGNAL
};

static guint signals[LAST_SIGNAL];

static void nautilus_clipboard_monitor_init       (gpointer              object,
						   gpointer              klass);
static void nautilus_clipboard_monitor_class_init (gpointer              klass);

EEL_CLASS_BOILERPLATE (NautilusClipboardMonitor,
		       nautilus_clipboard_monitor,
		       G_TYPE_OBJECT)

static NautilusClipboardMonitor *clipboard_monitor = NULL;

static void
destroy_clipboard_monitor (void)
{
	if (clipboard_monitor != NULL) {
		g_object_unref (clipboard_monitor);
	}
}

NautilusClipboardMonitor *
nautilus_clipboard_monitor_get (void)
{
	GtkClipboard *clipboard;
	
	if (clipboard_monitor == NULL) {
		clipboard_monitor = NAUTILUS_CLIPBOARD_MONITOR (g_object_new (NAUTILUS_TYPE_CLIPBOARD_MONITOR, NULL));
		eel_debug_call_at_shutdown (destroy_clipboard_monitor);
		
		clipboard = gtk_clipboard_get (GDK_SELECTION_CLIPBOARD);
		g_signal_connect (clipboard, "owner_change",
				  G_CALLBACK (nautilus_clipboard_monitor_emit_changed), NULL);
	}
	return clipboard_monitor;
}

void
nautilus_clipboard_monitor_emit_changed (void)
{
	NautilusClipboardMonitor *monitor;
  
	monitor = nautilus_clipboard_monitor_get ();
	
	g_signal_emit (monitor, signals[CLIPBOARD_CHANGED], 0);
}

static void
nautilus_clipboard_monitor_init (gpointer object, gpointer klass)
{
	NautilusClipboardMonitor *monitor;

	monitor = NAUTILUS_CLIPBOARD_MONITOR (object);
}	

static void
clipboard_monitor_finalize (GObject *object)
{
	NautilusClipboardMonitor *monitor;

	monitor = NAUTILUS_CLIPBOARD_MONITOR (object);

	EEL_CALL_PARENT (G_OBJECT_CLASS, finalize, (object));
}

static void
nautilus_clipboard_monitor_class_init (gpointer klass)
{
	GObjectClass *object_class;

	object_class = G_OBJECT_CLASS (klass);
	
	object_class->finalize = clipboard_monitor_finalize;

	signals[CLIPBOARD_CHANGED] =
		g_signal_new ("clipboard_changed",
		              G_TYPE_FROM_CLASS (klass),
		              G_SIGNAL_RUN_LAST,
		              G_STRUCT_OFFSET (NautilusClipboardMonitorClass, clipboard_changed),
		              NULL, NULL,
		              g_cclosure_marshal_VOID__VOID,
		              G_TYPE_NONE, 0);

}