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/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
/*
* Copyright (C) 2014 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, see <http://www.gnu.org/licenses/>.
*/
/*
* restart:
*
* Smoothly restart the compositor
*
* There are some cases where we need to restart Mutter in order
* to deal with changes in state - the particular case inspiring
* this is enabling or disabling stereo output. To make this
* fairly smooth for the user, we need to do two things:
*
* - Display a message to the user and make sure that it is
* actually painted before we exit.
* - Use a helper program so that the Composite Overlay Window
* isn't unmapped and mapped.
*
* This handles both of these.
*/
#include "config.h"
#include <gio/gunixinputstream.h>
#include "clutter/clutter.h"
#include "core/display-private.h"
#include "core/util-private.h"
#include "meta/main.h"
#include "x11/meta-x11-display-private.h"
static gboolean restart_helper_started = FALSE;
static gboolean restart_message_shown = FALSE;
static gboolean is_restart = FALSE;
void
meta_set_is_restart (gboolean whether)
{
is_restart = whether;
}
static void
restart_check_ready (MetaContext *context)
{
if (restart_helper_started && restart_message_shown)
{
MetaDisplay *display = meta_context_get_display (context);
if (!meta_display_request_restart (display))
meta_display_show_restart_message (display, NULL);
}
}
static void
restart_helper_read_line_callback (GObject *source_object,
GAsyncResult *res,
gpointer user_data)
{
MetaContext *context = user_data;
GError *error = NULL;
gsize length;
char *line = g_data_input_stream_read_line_finish_utf8 (G_DATA_INPUT_STREAM (source_object),
res,
&length, &error);
if (line == NULL)
{
meta_warning ("Failed to read output from restart helper%s%s",
error ? ": " : NULL,
error ? error->message : NULL);
}
else
g_free (line); /* We don't actually care what the restart helper outputs */
g_object_unref (source_object);
restart_helper_started = TRUE;
restart_check_ready (context);
}
static gboolean
restart_message_painted (gpointer user_data)
{
MetaContext *context = user_data;
restart_message_shown = TRUE;
restart_check_ready (context);
return FALSE;
}
static void
child_setup (gpointer user_data)
{
MetaDisplay *display = user_data;
MetaContext *context = meta_display_get_context (display);
meta_context_restore_rlimit_nofile (context, NULL);
}
/**
* meta_restart:
* @message: (allow-none): message to display to the user, or %NULL
* @context: a #MetaContext
*
* Starts the process of restarting the compositor.
*
* Note that Mutter's involvement here is to make the restart
* visually smooth for the user - it cannot itself safely
* reexec a program that embeds libmuttter.
*
* So in order for this to work, the compositor must handle two
* signals
*
* - [signal@Meta.Display::show-restart-message], to display the
* message passed here on the Clutter stage
* - [signal@Meta.Display::restart] to actually reexec the compositor.
*/
void
meta_restart (const char *message,
MetaContext *context)
{
MetaDisplay *display;
GInputStream *unix_stream;
GDataInputStream *data_stream;
GError *error = NULL;
int helper_out_fd;
static const char * const helper_argv[] = {
MUTTER_LIBEXECDIR "/mutter-restart-helper", NULL
};
g_return_if_fail (META_IS_CONTEXT (context));
display = meta_context_get_display (context);
if (message && meta_display_show_restart_message (display, message))
{
/* Wait until the stage was painted */
clutter_threads_add_repaint_func_full (CLUTTER_REPAINT_FLAGS_POST_PAINT,
restart_message_painted,
context, NULL);
}
else
{
/* Can't show the message, show the message as soon as the
* restart helper starts
*/
restart_message_painted (context);
}
/* We also need to wait for the restart helper to get its
* reference to the Composite Overlay Window.
*/
if (!g_spawn_async_with_pipes (NULL, /* working directory */
(char **)helper_argv,
NULL, /* envp */
G_SPAWN_DEFAULT,
child_setup, display,
NULL, /* child_pid */
NULL, /* standard_input */
&helper_out_fd,
NULL, /* standard_error */
&error))
{
meta_warning ("Failed to start restart helper: %s", error->message);
goto error;
}
unix_stream = g_unix_input_stream_new (helper_out_fd, TRUE);
data_stream = g_data_input_stream_new (unix_stream);
g_object_unref (unix_stream);
g_data_input_stream_read_line_async (data_stream, G_PRIORITY_DEFAULT,
NULL, restart_helper_read_line_callback,
context);
return;
error:
/* If starting the restart helper fails, then we just go ahead and restart
* immediately. We won't get a smooth transition, since the overlay window
* will be destroyed and recreated, but otherwise it will work fine.
*/
restart_helper_started = TRUE;
restart_check_ready (context);
return;
}
/**
* meta_is_restart:
*
* Returns %TRUE if this instance of Mutter comes from Mutter
* restarting itself (for example to enable/disable stereo.)
*
* See [func@Meta.restart]. If this is the case, any startup visuals
* or animations should be suppressed.
*/
gboolean
meta_is_restart (void)
{
return is_restart;
}
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