/* -*- mode: C; c-file-style: "gnu" -*- */
/* egg-dbus.c GLib main loop integration
 *
 * Copyright (C) 2002, 2003 CodeFactory AB
 * Copyright (C) 2005 Red Hat, Inc.
 *
 * Licensed under the Academic Free License version 2.1
 *
 * 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
 *
 */


#include "config.h"

#include "egg-dbus.h"

#include <dbus/dbus.h>

/*
 * dbus_watch_get_unix_fd() is introduced in dbus 1.1.1, deprecating
 * dbus_watch_get_fd(). We still need to use the old function for official
 * GNOME 2.20, anyway. See Bug #465936.
 */
#define VER_LESS_THAN(MAJOR, MINOR, MICRO, J, N, C) \
    (MAJOR < J || (MAJOR == J && (MINOR < N || (MINOR == N && MICRO < C))))
#if VER_LESS_THAN(GKR_DBUS_MAJOR_VERSION, GKR_DBUS_MINOR_VERSION, GKR_DBUS_MICRO_VERSION, 1, 1, 1)
# define dbus_watch_get_unix_fd dbus_watch_get_fd
#endif

/* ------------------------------------------------------------------------
 * DBUS GLIB MAIN LOOP INTEGRATION
 *
 * Copied from dbus-gmain.c due to API instabilities in dbus-glib bindings. :(
 */

typedef struct {
	GSource source;             /* the parent GSource */
	DBusConnection *connection; /* the connection to dispatch */
} DBusGMessageQueue;

static gboolean
message_queue_prepare (GSource *source, gint *timeout)
{
	DBusConnection *connection = ((DBusGMessageQueue *)source)->connection;
	*timeout = -1;
	return (dbus_connection_get_dispatch_status (connection) == DBUS_DISPATCH_DATA_REMAINS);
}

static gboolean
message_queue_check (GSource *source)
{
	return FALSE;
}

static gboolean
message_queue_dispatch (GSource *source, GSourceFunc  callback, gpointer user_data)
{
	DBusConnection *connection = ((DBusGMessageQueue *)source)->connection;
	dbus_connection_ref (connection);

	/* Only dispatch once - we don't want to starve other GSource */
	dbus_connection_dispatch (connection);
	dbus_connection_unref (connection);
	return TRUE;
}

static const GSourceFuncs message_queue_funcs = {
	message_queue_prepare,
	message_queue_check,
	message_queue_dispatch,
	NULL
};

typedef struct {
	GMainContext *context;         /* the main context */
	GSList *ios;                   /* all IOHandler */
	GSList *timeouts;              /* all TimeoutHandler */
	DBusConnection *connection;    /* NULL if this is really for a server not a connection */
	GSource *message_queue_source; /* DBusGMessageQueue */
} ConnectionSetup;

static ConnectionSetup *the_setup = NULL;

typedef struct {
	ConnectionSetup *cs;
	GSource *source;
	DBusWatch *watch;
} IOHandler;

typedef struct {
	ConnectionSetup *cs;
	GSource *source;
	DBusTimeout *timeout;
} TimeoutHandler;

static ConnectionSetup*
connection_setup_new (GMainContext *context, DBusConnection *connection)
{
	ConnectionSetup *cs = g_new0 (ConnectionSetup, 1);
	g_assert (context != NULL);

	cs->context = context;
	g_main_context_ref (cs->context);

	if (connection) {
		cs->connection = connection;
		cs->message_queue_source = g_source_new ((GSourceFuncs *) &message_queue_funcs,
		                                         sizeof (DBusGMessageQueue));
		((DBusGMessageQueue*)cs->message_queue_source)->connection = connection;
		g_source_attach (cs->message_queue_source, cs->context);
	}

	return cs;
}

static void
io_handler_source_finalized (gpointer data)
{
	IOHandler *handler = data;
	if (handler->watch)
		dbus_watch_set_data (handler->watch, NULL, NULL);
	g_free (handler);
}

static void
io_handler_destroy_source (void *data)
{
	IOHandler *handler = data;
	if (handler->source) {
		GSource *source = handler->source;
		handler->source = NULL;
		handler->cs->ios = g_slist_remove (handler->cs->ios, handler);
		g_source_destroy (source);
		g_source_unref (source);
	}
}

static void
io_handler_watch_freed (void *data)
{
	IOHandler *handler = data;
	handler->watch = NULL;
	io_handler_destroy_source (handler);
}

static gboolean
io_handler_dispatch (GIOChannel *source, GIOCondition condition, gpointer data)
{
	IOHandler *handler = data;
	guint dbus_condition = 0;
	DBusConnection *connection = handler->cs->connection;

	if (connection)
		dbus_connection_ref (connection);

	if (condition & G_IO_IN)
		dbus_condition |= DBUS_WATCH_READABLE;
	if (condition & G_IO_OUT)
		dbus_condition |= DBUS_WATCH_WRITABLE;
	if (condition & G_IO_ERR)
		dbus_condition |= DBUS_WATCH_ERROR;
	if (condition & G_IO_HUP)
		dbus_condition |= DBUS_WATCH_HANGUP;

	/* Note that we don't touch the handler after this, because
	 * dbus may have disabled the watch and thus killed the
	 * handler.
	 */
	dbus_watch_handle (handler->watch, dbus_condition);
	handler = NULL;

	if (connection)
		dbus_connection_unref (connection);

	return TRUE;
}

static void
connection_setup_add_watch (ConnectionSetup *cs, DBusWatch *watch)
{
	guint flags;
	GIOCondition condition;
	GIOChannel *channel;
	IOHandler *handler;

	if (!dbus_watch_get_enabled (watch))
		return;

	g_assert (dbus_watch_get_data (watch) == NULL);

	flags = dbus_watch_get_flags (watch);

	condition = G_IO_ERR | G_IO_HUP;
	if (flags & DBUS_WATCH_READABLE)
		condition |= G_IO_IN;
	if (flags & DBUS_WATCH_WRITABLE)
		condition |= G_IO_OUT;

	handler = g_new0 (IOHandler, 1);
	handler->cs = cs;
	handler->watch = watch;

	channel = g_io_channel_unix_new (dbus_watch_get_unix_fd (watch));

	handler->source = g_io_create_watch (channel, condition);
	g_source_set_callback (handler->source, (GSourceFunc) io_handler_dispatch, handler,
	                       io_handler_source_finalized);
	g_source_attach (handler->source, cs->context);

	cs->ios = g_slist_prepend (cs->ios, handler);

	dbus_watch_set_data (watch, handler, io_handler_watch_freed);
	g_io_channel_unref (channel);
}

static void
connection_setup_remove_watch (ConnectionSetup *cs, DBusWatch *watch)
{
	IOHandler *handler = dbus_watch_get_data (watch);
	if (handler != NULL)
		io_handler_destroy_source (handler);
}

static void
timeout_handler_source_finalized (gpointer data)
{
	TimeoutHandler *handler = data;
	if (handler->timeout)
		dbus_timeout_set_data (handler->timeout, NULL, NULL);
	g_free (handler);
}

static void
timeout_handler_destroy_source (void *data)
{
	TimeoutHandler *handler = data;
	if (handler->source) {
		GSource *source = handler->source;
		handler->source = NULL;
		handler->cs->timeouts = g_slist_remove (handler->cs->timeouts, handler);
		g_source_destroy (source);
		g_source_unref (source);
	}
}

static void
timeout_handler_timeout_freed (void *data)
{
	TimeoutHandler *handler = data;
	handler->timeout = NULL;
	timeout_handler_destroy_source (handler);
}

static gboolean
timeout_handler_dispatch (gpointer      data)
{
	TimeoutHandler *handler = data;
	dbus_timeout_handle (handler->timeout);
	return TRUE;
}

static void
connection_setup_add_timeout (ConnectionSetup *cs,
                              DBusTimeout     *timeout)
{
	TimeoutHandler *handler;
	if (!dbus_timeout_get_enabled (timeout))
		return;
	g_assert (dbus_timeout_get_data (timeout) == NULL);

	handler = g_new0 (TimeoutHandler, 1);
	handler->cs = cs;
	handler->timeout = timeout;

	handler->source = g_timeout_source_new (dbus_timeout_get_interval (timeout));
	g_source_set_callback (handler->source, timeout_handler_dispatch, handler,
	                       timeout_handler_source_finalized);
	g_source_attach (handler->source, handler->cs->context);
	cs->timeouts = g_slist_prepend (cs->timeouts, handler);
	dbus_timeout_set_data (timeout, handler, timeout_handler_timeout_freed);
}

static void
connection_setup_remove_timeout (ConnectionSetup *cs, DBusTimeout *timeout)
{
	TimeoutHandler *handler = dbus_timeout_get_data (timeout);
	if (handler != NULL)
		timeout_handler_destroy_source (handler);
}

static void
connection_setup_free (ConnectionSetup *cs)
{
	while (cs->ios)
		io_handler_destroy_source (cs->ios->data);

	while (cs->timeouts)
		timeout_handler_destroy_source (cs->timeouts->data);

	if (cs->message_queue_source) {
		GSource *source = cs->message_queue_source;
		cs->message_queue_source = NULL;

		g_source_destroy (source);
		g_source_unref (source);
	}

	g_main_context_unref (cs->context);
	g_free (cs);
}

static dbus_bool_t
add_watch (DBusWatch *watch, gpointer data)
{
	ConnectionSetup *cs = data;
	connection_setup_add_watch (cs, watch);
	return TRUE;
}

static void
remove_watch (DBusWatch *watch, gpointer data)
{
	ConnectionSetup *cs = data;
	connection_setup_remove_watch (cs, watch);
}

static void
watch_toggled (DBusWatch *watch, void *data)
{
	if (dbus_watch_get_enabled (watch))
		add_watch (watch, data);
	else
		remove_watch (watch, data);
}

static dbus_bool_t
add_timeout (DBusTimeout *timeout, void *data)
{
	ConnectionSetup *cs = data;
	if (!dbus_timeout_get_enabled (timeout))
		return TRUE;
	connection_setup_add_timeout (cs, timeout);
	return TRUE;
}

static void
remove_timeout (DBusTimeout *timeout, void *data)
{
	ConnectionSetup *cs = data;
	connection_setup_remove_timeout (cs, timeout);
}

static void
timeout_toggled (DBusTimeout *timeout, void *data)
{
	if (dbus_timeout_get_enabled (timeout))
		add_timeout (timeout, data);
	else
		remove_timeout (timeout, data);
}

static void
wakeup_main (void *data)
{
	ConnectionSetup *cs = data;
	g_main_context_wakeup (cs->context);
}

void
egg_dbus_connect_with_mainloop (DBusConnection *connection, GMainContext *context)
{
	ConnectionSetup *cs;

	if (context == NULL)
		context = g_main_context_default ();
	cs = connection_setup_new (context, connection);
	the_setup = cs;

	if (!dbus_connection_set_watch_functions (connection, add_watch,
	                                          remove_watch, watch_toggled,
	                                          cs, NULL))
		goto nomem;

	if (!dbus_connection_set_timeout_functions (connection, add_timeout,
	                                            remove_timeout, timeout_toggled,
	                                            cs, NULL))
		goto nomem;

	dbus_connection_set_wakeup_main_function (connection, wakeup_main, cs, NULL);

	return;

nomem:
	g_error ("Not enough memory to set up DBusConnection for use with GLib");
}

void
egg_dbus_disconnect_from_mainloop (DBusConnection *connection, GMainContext *context)
{
	ConnectionSetup *cs = the_setup;
	the_setup = NULL;

	if (cs)
		connection_setup_free (cs);
}