display.c

/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */

/*
 * Copyright (C) 2001 Havoc Pennington
 * Copyright (C) 2002, 2003, 2004 Red Hat, Inc.
 * Copyright (C) 2003, 2004 Rob Adams
 * Copyright (C) 2004-2006 Elijah Newren
 *
 * 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/>.
 */

/**
 * SECTION:display
 * @title: MetaDisplay
 * @short_description: Mutter X display handler
 *
 * The display is represented as a #MetaDisplay struct.
 */

#define _XOPEN_SOURCE 600 /* for gethostname() */

#include <config.h>
#include "display-private.h"
#include "events.h"
#include "util-private.h"
#include <meta/main.h>
#include "screen-private.h"
#include "window-private.h"
#include "frame.h"
#include <meta/errors.h>
#include "keybindings-private.h"
#include <meta/prefs.h>
#include "workspace-private.h"
#include "bell.h"
#include <meta/compositor.h>
#include <meta/compositor-mutter.h>
#include <X11/Xatom.h>
#include "mutter-enum-types.h"
#include "meta-idle-monitor-dbus.h"
#include "meta-cursor-tracker-private.h"
#include "meta-backend.h"
#include "backends/x11/meta-backend-x11.h"
#include <clutter/x11/clutter-x11.h>

#ifdef HAVE_RANDR
#include <X11/extensions/Xrandr.h>
#endif
#include <X11/extensions/shape.h>
#include <X11/Xcursor/Xcursor.h>
#include <X11/extensions/Xcomposite.h>
#include <X11/extensions/Xdamage.h>
#include <X11/extensions/Xfixes.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "x11/window-x11.h"
#include "x11/window-props.h"
#include "x11/group-props.h"
#include "x11/xprops.h"

#include "wayland/meta-xwayland-private.h"

/*
 * SECTION:pings
 *
 * Sometimes we want to see whether a window is responding,
 * so we send it a "ping" message and see whether it sends us back a "pong"
 * message within a reasonable time. Here we have a system which lets us
 * nominate one function to be called if we get the pong in time and another
 * function if we don't. The system is rather more complicated than it needs
 * to be, since we only ever use it to destroy windows which are asked to
 * close themselves and don't do so within a reasonable amount of time, and
 * therefore we always use the same callbacks. It's possible that we might
 * use it for other things in future, or on the other hand we might decide
 * that we're never going to do so and simplify it a bit.
 */

/**
 * MetaPingData:
 *
 * Describes a ping on a window. When we send a ping to a window, we build
 * one of these structs, and it eventually gets passed to the timeout function
 * or to the function which handles the response from the window. If the window
 * does or doesn't respond to the ping, we use this information to deal with
 * these facts; we have a handler function for each.
 */
typedef struct
{
  MetaWindow *window;
  guint32     serial;
  guint       ping_timeout_id;
} MetaPingData;

G_DEFINE_TYPE(MetaDisplay, meta_display, G_TYPE_OBJECT);

/* Signals */
enum
{
  OVERLAY_KEY,
  ACCELERATOR_ACTIVATED,
  MODIFIERS_ACCELERATOR_ACTIVATED,
  FOCUS_WINDOW,
  WINDOW_CREATED,
  WINDOW_DEMANDS_ATTENTION,
  WINDOW_MARKED_URGENT,
  GRAB_OP_BEGIN,
  GRAB_OP_END,
  SHOW_RESTART_MESSAGE,
  RESTART,
  LAST_SIGNAL
};

enum {
  PROP_0,

  PROP_FOCUS_WINDOW
};

static guint display_signals [LAST_SIGNAL] = { 0 };

/*
 * The display we're managing.  This is a singleton object.  (Historically,
 * this was a list of displays, but there was never any way to add more
 * than one element to it.)  The goofy name is because we don't want it
 * to shadow the parameter in its object methods.
 */
static MetaDisplay *the_display = NULL;


static const char *gnome_wm_keybindings = "Mutter";
static const char *net_wm_name = "Mutter";

static void update_cursor_theme (void);
static void    update_window_grab_modifiers (MetaDisplay *display);

static void    prefs_changed_callback    (MetaPreference pref,
                                          void          *data);

static void
meta_display_get_property(GObject         *object,
                          guint            prop_id,
                          GValue          *value,
                          GParamSpec      *pspec)
{
  MetaDisplay *display = META_DISPLAY (object);

  switch (prop_id)
    {
    case PROP_FOCUS_WINDOW:
      g_value_set_object (value, display->focus_window);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
    }
}

static void
meta_display_set_property(GObject         *object,
                          guint            prop_id,
                          const GValue    *value,
                          GParamSpec      *pspec)
{
  switch (prop_id)
    {
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
    }
}

static void
meta_display_class_init (MetaDisplayClass *klass)
{
  GObjectClass *object_class = G_OBJECT_CLASS (klass);

  object_class->get_property = meta_display_get_property;
  object_class->set_property = meta_display_set_property;

  display_signals[OVERLAY_KEY] =
    g_signal_new ("overlay-key",
                  G_TYPE_FROM_CLASS (klass),
                  G_SIGNAL_RUN_LAST,
                  0,
                  NULL, NULL, NULL,
                  G_TYPE_NONE, 0);

  display_signals[ACCELERATOR_ACTIVATED] =
    g_signal_new ("accelerator-activated",
                  G_TYPE_FROM_CLASS (klass),
                  G_SIGNAL_RUN_LAST,
                  0,
                  NULL, NULL, NULL,
                  G_TYPE_NONE, 3, G_TYPE_UINT, G_TYPE_UINT, G_TYPE_UINT);

  /**
   * MetaDisplay::modifiers-accelerator-activated:
   * @display: the #MetaDisplay instance
   *
   * The ::modifiers-accelerator-activated signal will be emitted when
   * a special modifiers-only keybinding is activated.
   *
   * Returns: %TRUE means that the keyboard device should remain
   *    frozen and %FALSE for the default behavior of unfreezing the
   *    keyboard.
   */
  display_signals[MODIFIERS_ACCELERATOR_ACTIVATED] =
    g_signal_new ("modifiers-accelerator-activated",
                  G_TYPE_FROM_CLASS (klass),
                  G_SIGNAL_RUN_LAST,
                  0,
                  g_signal_accumulator_first_wins, NULL, NULL,
                  G_TYPE_BOOLEAN, 0);

  display_signals[WINDOW_CREATED] =
    g_signal_new ("window-created",
                  G_TYPE_FROM_CLASS (klass),
                  G_SIGNAL_RUN_LAST,
                  0,
                  NULL, NULL, NULL,
                  G_TYPE_NONE, 1, META_TYPE_WINDOW);

  display_signals[WINDOW_DEMANDS_ATTENTION] =
    g_signal_new ("window-demands-attention",
                  G_TYPE_FROM_CLASS (klass),
                  G_SIGNAL_RUN_LAST,
                  0,
                  NULL, NULL, NULL,
                  G_TYPE_NONE, 1, META_TYPE_WINDOW);

  display_signals[WINDOW_MARKED_URGENT] =
    g_signal_new ("window-marked-urgent",
                  G_TYPE_FROM_CLASS (klass),
                  G_SIGNAL_RUN_LAST,
                  0,
                  NULL, NULL, NULL,
                  G_TYPE_NONE, 1,
                  META_TYPE_WINDOW);

  display_signals[GRAB_OP_BEGIN] =
    g_signal_new ("grab-op-begin",
                  G_TYPE_FROM_CLASS (klass),
                  G_SIGNAL_RUN_LAST,
                  0,
                  NULL, NULL, NULL,
                  G_TYPE_NONE, 3,
                  META_TYPE_SCREEN,
                  META_TYPE_WINDOW,
                  META_TYPE_GRAB_OP);

  display_signals[GRAB_OP_END] =
    g_signal_new ("grab-op-end",
                  G_TYPE_FROM_CLASS (klass),
                  G_SIGNAL_RUN_LAST,
                  0,
                  NULL, NULL, NULL,
                  G_TYPE_NONE, 3,
                  META_TYPE_SCREEN,
                  META_TYPE_WINDOW,
                  META_TYPE_GRAB_OP);

  /**
   * MetaDisplay::show-restart-message:
   * @display: the #MetaDisplay instance
   * @message: (allow-none): The message to display, or %NULL
   *  to clear a previous restart message.
   *
   * The ::show-restart-message signal will be emitted to indicate
   * that the compositor should show a message during restart. This is
   * emitted when meta_restart() is called, either by Mutter
   * internally or by the embedding compositor.  The message should be
   * immediately added to the Clutter stage in its final form -
   * ::restart will be emitted to exit the application and leave the
   * stage contents frozen as soon as the the stage is painted again.
   *
   * On case of failure to restart, this signal will be emitted again
   * with %NULL for @message.
   *
   * Returns: %TRUE means the message was added to the stage; %FALSE
   *   indicates that the compositor did not show the message.
   */
  display_signals[SHOW_RESTART_MESSAGE] =
    g_signal_new ("show-restart-message",
                  G_TYPE_FROM_CLASS (klass),
                  G_SIGNAL_RUN_LAST,
                  0,
                  g_signal_accumulator_true_handled,
                  NULL, NULL,
                  G_TYPE_BOOLEAN, 1,
                  G_TYPE_STRING);

  /**
   * MetaDisplay::restart:
   * @display: the #MetaDisplay instance
   *
   * The ::restart signal is emitted to indicate that compositor
   * should reexec the process. This is
   * emitted when meta_restart() is called, either by Mutter
   * internally or by the embedding compositor. See also
   * ::show-restart-message.
   *
   * Returns: %FALSE to indicate that the compositor could not
   *  be restarted. When the compositor is restarted, the signal
   *  should not return.
   */
  display_signals[RESTART] =
    g_signal_new ("restart",
                  G_TYPE_FROM_CLASS (klass),
                  G_SIGNAL_RUN_LAST,
                  0,
                  g_signal_accumulator_true_handled,
                  NULL, NULL,
                  G_TYPE_BOOLEAN, 0);

  g_object_class_install_property (object_class,
                                   PROP_FOCUS_WINDOW,
                                   g_param_spec_object ("focus-window",
                                                        "Focus window",
                                                        "Currently focused window",
                                                        META_TYPE_WINDOW,
                                                        G_PARAM_READABLE));
}


/**
 * ping_data_free:
 *
 * Destructor for #MetaPingData structs. Will destroy the
 * event source for the struct as well.
 */
static void
ping_data_free (MetaPingData *ping_data)
{
  /* Remove the timeout */
  if (ping_data->ping_timeout_id != 0)
    g_source_remove (ping_data->ping_timeout_id);

  g_free (ping_data);
}

void
meta_display_remove_pending_pings_for_window (MetaDisplay *display,
                                              MetaWindow  *window)
{
  GSList *tmp;
  GSList *dead;

  /* could obviously be more efficient, don't care */

  /* build list to be removed */
  dead = NULL;
  for (tmp = display->pending_pings; tmp; tmp = tmp->next)
    {
      MetaPingData *ping_data = tmp->data;

      if (ping_data->window == window)
        dead = g_slist_prepend (dead, ping_data);
    }

  /* remove what we found */
  for (tmp = dead; tmp; tmp = tmp->next)
    {
      MetaPingData *ping_data = tmp->data;

      display->pending_pings = g_slist_remove (display->pending_pings, ping_data);
      ping_data_free (ping_data);
    }

  g_slist_free (dead);
}


#ifdef HAVE_STARTUP_NOTIFICATION
static void
sn_error_trap_push (SnDisplay *sn_display,
                    Display   *xdisplay)
{
  MetaDisplay *display;
  display = meta_display_for_x_display (xdisplay);
  if (display != NULL)
    meta_error_trap_push (display);
}

static void
sn_error_trap_pop (SnDisplay *sn_display,
                   Display   *xdisplay)
{
  MetaDisplay *display;
  display = meta_display_for_x_display (xdisplay);
  if (display != NULL)
    meta_error_trap_pop (display);
}
#endif

static void
enable_compositor (MetaDisplay *display)
{
  if (!META_DISPLAY_HAS_COMPOSITE (display) ||
      !META_DISPLAY_HAS_DAMAGE (display))
    {
      meta_warning ("Missing %s extension required for compositing",
                    !META_DISPLAY_HAS_COMPOSITE (display) ? "composite" : "damage");
      return;
    }

  if (!display->compositor)
      display->compositor = meta_compositor_new (display);

  if (!display->compositor)
    return;

  meta_compositor_manage (display->compositor);
}

static void
meta_display_init (MetaDisplay *disp)
{
  /* Some stuff could go in here that's currently in _open,
   * but it doesn't really matter. */
}

/**
 * meta_set_wm_name: (skip)
 * @wm_name: value for _NET_WM_NAME
 *
 * Set the value to use for the _NET_WM_NAME property. To take effect,
 * it is necessary to call this function before meta_init().
 */
void
meta_set_wm_name (const char *wm_name)
{
  g_return_if_fail (the_display == NULL);

  net_wm_name = wm_name;
}

/**
 * meta_set_gnome_wm_keybindings: (skip)
 * @wm_keybindings: value for _GNOME_WM_KEYBINDINGS
 *
 * Set the value to use for the _GNOME_WM_KEYBINDINGS property. To take
 * effect, it is necessary to call this function before meta_init().
 */
void
meta_set_gnome_wm_keybindings (const char *wm_keybindings)
{
  g_return_if_fail (the_display == NULL);

  gnome_wm_keybindings = wm_keybindings;
}

void
meta_display_cancel_touch (MetaDisplay *display)
{
  MetaWaylandCompositor *compositor;

  if (!meta_is_wayland_compositor ())
    return;

  compositor = meta_wayland_compositor_get_default ();
  meta_wayland_touch_cancel (&compositor->seat->touch);
}

static void
gesture_tracker_state_changed (MetaGestureTracker   *tracker,
                               ClutterEventSequence *sequence,
                               MetaSequenceState     state,
                               MetaDisplay          *display)
{
  if (meta_is_wayland_compositor ())
    {
      if (state == META_SEQUENCE_ACCEPTED)
        meta_display_cancel_touch (display);
    }
  else
    {
      MetaBackendX11 *backend = META_BACKEND_X11 (meta_get_backend ());
      int event_mode;

      if (state == META_SEQUENCE_ACCEPTED)
        event_mode = XIAcceptTouch;
      else if (state == META_SEQUENCE_REJECTED)
        event_mode = XIRejectTouch;
      else
        return;

      XIAllowTouchEvents (meta_backend_x11_get_xdisplay (backend),
                          META_VIRTUAL_CORE_POINTER_ID,
                          clutter_x11_event_sequence_get_touch_detail (sequence),
                          DefaultRootWindow (display->xdisplay), event_mode);
    }
}

/**
 * meta_display_open:
 *
 * Opens a new display, sets it up, initialises all the X extensions
 * we will need, and adds it to the list of displays.
 *
 * Returns: %TRUE if the display was opened successfully, and %FALSE
 * otherwise-- that is, if the display doesn't exist or it already
 * has a window manager.
 */
gboolean
meta_display_open (void)
{
  MetaDisplay *display;
  Display *xdisplay;
  MetaScreen *screen;
  int i;
  guint32 timestamp;

  /* A list of all atom names, so that we can intern them in one go. */
  char *atom_names[] = {
#define item(x) #x,
#include <meta/atomnames.h>
#undef item
  };
  Atom atoms[G_N_ELEMENTS(atom_names)];

  meta_verbose ("Opening display '%s'\n", XDisplayName (NULL));

  xdisplay = meta_ui_get_display ();

  if (xdisplay == NULL)
    {
      meta_warning (_("Failed to open X Window System display '%s'\n"),
		    XDisplayName (NULL));
      return FALSE;
    }

  if (meta_is_wayland_compositor ())
    meta_xwayland_complete_init ();

  if (meta_is_syncing ())
    XSynchronize (xdisplay, True);

  g_assert (the_display == NULL);
  display = the_display = g_object_new (META_TYPE_DISPLAY, NULL);

  display->closing = 0;

  /* here we use XDisplayName which is what the user
   * probably put in, vs. DisplayString(display) which is
   * canonicalized by XOpenDisplay()
   */
  display->name = g_strdup (XDisplayName (NULL));
  display->xdisplay = xdisplay;
  display->display_opening = TRUE;

  display->pending_pings = NULL;
  display->autoraise_timeout_id = 0;
  display->autoraise_window = NULL;
  display->focus_window = NULL;
  display->focus_serial = 0;
  display->server_focus_window = None;
  display->server_focus_serial = 0;

  display->mouse_mode = TRUE; /* Only relevant for mouse or sloppy focus */
  display->allow_terminal_deactivation = TRUE; /* Only relevant for when a
                                                  terminal has the focus */

  meta_bell_init (display);

  meta_display_init_keys (display);

  update_window_grab_modifiers (display);

  meta_prefs_add_listener (prefs_changed_callback, display);

  meta_verbose ("Creating %d atoms\n", (int) G_N_ELEMENTS (atom_names));
  XInternAtoms (display->xdisplay, atom_names, G_N_ELEMENTS (atom_names),
                False, atoms);
  {
    int i = 0;
#define item(x) display->atom_##x = atoms[i++];
#include <meta/atomnames.h>
#undef item
  }

  display->prop_hooks = NULL;
  meta_display_init_window_prop_hooks (display);
  display->group_prop_hooks = NULL;
  meta_display_init_group_prop_hooks (display);

  /* Offscreen unmapped window used for _NET_SUPPORTING_WM_CHECK,
   * created in screen_new
   */
  display->leader_window = None;
  display->timestamp_pinging_window = None;

  display->monitor_cache_invalidated = TRUE;

  display->groups_by_leader = NULL;

  display->screen = NULL;

#ifdef HAVE_STARTUP_NOTIFICATION
  display->sn_display = sn_display_new (display->xdisplay,
                                        sn_error_trap_push,
                                        sn_error_trap_pop);
#endif

  /* Get events */
  meta_display_init_events (display);

  display->xids = g_hash_table_new (meta_unsigned_long_hash,
                                        meta_unsigned_long_equal);
  display->wayland_windows = g_hash_table_new (NULL, NULL);

  i = 0;
  while (i < N_IGNORED_CROSSING_SERIALS)
    {
      display->ignored_crossing_serials[i] = 0;
      ++i;
    }
  display->ungrab_should_not_cause_focus_window = None;

  display->current_time = CurrentTime;
  display->sentinel_counter = 0;

  display->grab_resize_timeout_id = 0;
  display->grab_have_keyboard = FALSE;

#ifdef HAVE_XKB
  display->last_bell_time = 0;
#endif

  display->grab_op = META_GRAB_OP_NONE;
  display->grab_window = NULL;
  display->grab_tile_mode = META_TILE_NONE;
  display->grab_tile_monitor_number = -1;

  display->grab_edge_resistance_data = NULL;

  {
    int major, minor;

    display->have_xsync = FALSE;

    display->xsync_error_base = 0;
    display->xsync_event_base = 0;

    /* I don't think we really have to fill these in */
    major = SYNC_MAJOR_VERSION;
    minor = SYNC_MINOR_VERSION;

    if (!XSyncQueryExtension (display->xdisplay,
                              &display->xsync_event_base,
                              &display->xsync_error_base) ||
        !XSyncInitialize (display->xdisplay,
                          &major, &minor))
      {
        display->xsync_error_base = 0;
        display->xsync_event_base = 0;
      }
    else
      {
        display->have_xsync = TRUE;
        XSyncSetPriority (display->xdisplay, None, 10);
      }

    meta_verbose ("Attempted to init Xsync, found version %d.%d error base %d event base %d\n",
                  major, minor,
                  display->xsync_error_base,
                  display->xsync_event_base);
  }

  {
    display->have_shape = FALSE;

    display->shape_error_base = 0;
    display->shape_event_base = 0;

    if (!XShapeQueryExtension (display->xdisplay,
                               &display->shape_event_base,
                               &display->shape_error_base))
      {
        display->shape_error_base = 0;
        display->shape_event_base = 0;
      }
    else
      display->have_shape = TRUE;

    meta_verbose ("Attempted to init Shape, found error base %d event base %d\n",
                  display->shape_error_base,
                  display->shape_event_base);
  }

  {
    display->have_composite = FALSE;

    display->composite_error_base = 0;
    display->composite_event_base = 0;

    if (!XCompositeQueryExtension (display->xdisplay,
                                   &display->composite_event_base,
                                   &display->composite_error_base))
      {
        display->composite_error_base = 0;
        display->composite_event_base = 0;
      }
    else
      {
        display->composite_major_version = 0;
        display->composite_minor_version = 0;
        if (XCompositeQueryVersion (display->xdisplay,
                                    &display->composite_major_version,
                                    &display->composite_minor_version))
          {
            display->have_composite = TRUE;
          }
        else
          {
            display->composite_major_version = 0;
            display->composite_minor_version = 0;
          }
      }

    meta_verbose ("Attempted to init Composite, found error base %d event base %d "
                  "extn ver %d %d\n",
                  display->composite_error_base,
                  display->composite_event_base,
                  display->composite_major_version,
                  display->composite_minor_version);

    display->have_damage = FALSE;

    display->damage_error_base = 0;
    display->damage_event_base = 0;

    if (!XDamageQueryExtension (display->xdisplay,
                                &display->damage_event_base,
                                &display->damage_error_base))
      {
        display->damage_error_base = 0;
        display->damage_event_base = 0;
      }
    else
      display->have_damage = TRUE;

    meta_verbose ("Attempted to init Damage, found error base %d event base %d\n",
                  display->damage_error_base,
                  display->damage_event_base);

    display->xfixes_error_base = 0;
    display->xfixes_event_base = 0;

    if (XFixesQueryExtension (display->xdisplay,
                              &display->xfixes_event_base,
                              &display->xfixes_error_base))
      {
        int xfixes_major, xfixes_minor;

        XFixesQueryVersion (display->xdisplay, &xfixes_major, &xfixes_minor);

        if (xfixes_major * 100 + xfixes_minor < 500)
          meta_fatal ("Mutter requires XFixes 5.0");
      }
    else
      {
        meta_fatal ("Mutter requires XFixes 5.0");
      }

    meta_verbose ("Attempted to init XFixes, found error base %d event base %d\n",
                  display->xfixes_error_base,
                  display->xfixes_event_base);
  }

  {
    int major = 2, minor = 3;
    gboolean has_xi = FALSE;

    if (XQueryExtension (display->xdisplay,
                         "XInputExtension",
                         &display->xinput_opcode,
                         &display->xinput_error_base,
                         &display->xinput_event_base))
      {
        if (XIQueryVersion (display->xdisplay, &major, &minor) == Success)
          {
            int version = (major * 10) + minor;
            if (version >= 22)
              has_xi = TRUE;

#ifdef HAVE_XI23
            if (version >= 23)
              display->have_xinput_23 = TRUE;
#endif /* HAVE_XI23 */
          }
      }

    if (!has_xi)
      meta_fatal ("X server doesn't have the XInput extension, version 2.2 or newer\n");
  }

  update_cursor_theme ();

  /* Create the leader window here. Set its properties and
   * use the timestamp from one of the PropertyNotify events
   * that will follow.
   */
  {
    gulong data[1];
    XEvent event;

    /* We only care about the PropertyChangeMask in the next 30 or so lines of
     * code.  Note that gdk will at some point unset the PropertyChangeMask for
     * this window, so we can't rely on it still being set later.  See bug
     * 354213 for details.
     */
    display->leader_window =
      meta_create_offscreen_window (display->xdisplay,
                                    DefaultRootWindow (display->xdisplay),
                                    PropertyChangeMask);

    meta_prop_set_utf8_string_hint (display,
                                    display->leader_window,
                                    display->atom__NET_WM_NAME,
                                    net_wm_name);

    meta_prop_set_utf8_string_hint (display,
                                    display->leader_window,
                                    display->atom__GNOME_WM_KEYBINDINGS,
                                    gnome_wm_keybindings);

    meta_prop_set_utf8_string_hint (display,
                                    display->leader_window,
                                    display->atom__MUTTER_VERSION,
                                    VERSION);

    data[0] = display->leader_window;
    XChangeProperty (display->xdisplay,
                     display->leader_window,
                     display->atom__NET_SUPPORTING_WM_CHECK,
                     XA_WINDOW,
                     32, PropModeReplace, (guchar*) data, 1);

    XWindowEvent (display->xdisplay,
                  display->leader_window,
                  PropertyChangeMask,
                  &event);

    timestamp = event.xproperty.time;

    /* Make it painfully clear that we can't rely on PropertyNotify events on
     * this window, as per bug 354213.
     */
    XSelectInput(display->xdisplay,
                 display->leader_window,
                 NoEventMask);
  }

  /* Make a little window used only for pinging the server for timestamps; note
   * that meta_create_offscreen_window already selects for PropertyChangeMask.
   */
  display->timestamp_pinging_window =
    meta_create_offscreen_window (display->xdisplay,
                                  DefaultRootWindow (display->xdisplay),
                                  PropertyChangeMask);

  display->last_focus_time = timestamp;
  display->last_user_time = timestamp;
  display->compositor = NULL;

  /* Mutter used to manage all X screens of the display in a single process, but
   * now it always manages exactly one screen as specified by the DISPLAY
   * environment variable.
   */
  i = meta_ui_get_screen_number ();
  screen = meta_screen_new (display, i, timestamp);

  if (!screen)
    {
      /* This would typically happen because all the screens already
       * have window managers.
       */
      meta_display_close (display, timestamp);
      return FALSE;
    }

  display->screen = screen;

  meta_screen_init_workspaces (screen);

  enable_compositor (display);

  meta_screen_create_guard_window (screen);

  /* Set up touch support */
  display->gesture_tracker = meta_gesture_tracker_new ();
  g_signal_connect (display->gesture_tracker, "state-changed",
                    G_CALLBACK (gesture_tracker_state_changed), display);

  /* We know that if mutter is running as a Wayland compositor,
   * we start out with no windows.
   */
  if (!meta_is_wayland_compositor ())
    meta_screen_manage_all_windows (screen);

  {
    Window focus;
    int ret_to;

    /* kinda bogus because GetInputFocus has no possible errors */
    meta_error_trap_push (display);

    /* FIXME: This is totally broken; see comment 9 of bug 88194 about this */
    focus = None;
    ret_to = RevertToPointerRoot;
    XGetInputFocus (display->xdisplay, &focus, &ret_to);

    /* Force a new FocusIn (does this work?) */

    /* Use the same timestamp that was passed to meta_screen_new(),
     * as it is the most recent timestamp.
     */
    if (focus == None || focus == PointerRoot)
      /* Just focus the no_focus_window on the first screen */
      meta_display_focus_the_no_focus_window (display,
                                              display->screen,
                                              timestamp);
    else
      {
        MetaWindow * window;
        window  = meta_display_lookup_x_window (display, focus);
        if (window)
          meta_display_set_input_focus_window (display, window, FALSE, timestamp);
        else
          /* Just focus the no_focus_window on the first screen */
          meta_display_focus_the_no_focus_window (display,
                                                  display->screen,
                                                  timestamp);
      }

    meta_error_trap_pop (display);
  }

  meta_idle_monitor_init_dbus ();

  /* Done opening new display */
  display->display_opening = FALSE;

  return TRUE;
}

static gint
ptrcmp (gconstpointer a, gconstpointer b)
{
  if (a < b)
    return -1;
  else if (a > b)
    return 1;
  else
    return 0;
}

/**
 * meta_display_list_windows:
 * @display: a #MetaDisplay
 * @flags: options for listing
 *
 * Lists windows for the display, the @flags parameter for
 * now determines whether override-redirect windows will be
 * included.
 *
 * Return value: (transfer container): the list of windows.
 */
GSList*
meta_display_list_windows (MetaDisplay          *display,
                           MetaListWindowsFlags  flags)
{
  GSList *winlist;
  GSList *prev;
  GSList *tmp;
  GHashTableIter iter;
  gpointer key, value;

  winlist = NULL;

  g_hash_table_iter_init (&iter, display->xids);
  while (g_hash_table_iter_next (&iter, &key, &value))
    {
      MetaWindow *window = value;

      if (!META_IS_WINDOW (window))
        continue;

      if (!window->override_redirect ||
          (flags & META_LIST_INCLUDE_OVERRIDE_REDIRECT) != 0)
        winlist = g_slist_prepend (winlist, window);
    }

  g_hash_table_iter_init (&iter, display->wayland_windows);
  while (g_hash_table_iter_next (&iter, &key, &value))
    {
      MetaWindow *window = value;

      if (!META_IS_WINDOW (window))
        continue;

      if (!window->override_redirect ||
          (flags & META_LIST_INCLUDE_OVERRIDE_REDIRECT) != 0)
        winlist = g_slist_prepend (winlist, window);
    }

  /* Uniquify the list, since both frame windows and plain
   * windows are in the hash
   */
  winlist = g_slist_sort (winlist, ptrcmp);

  prev = NULL;
  tmp = winlist;
  while (tmp != NULL)
    {
      GSList *next;

      next = tmp->next;

      if (next &&
          next->data == tmp->data)
        {
          /* Delete tmp from list */

          if (prev)
            prev->next = next;

          if (tmp == winlist)
            winlist = next;

          g_slist_free_1 (tmp);

          /* leave prev unchanged */
        }
      else
        {
          prev = tmp;
        }

      tmp = next;
    }

  return winlist;
}

void
meta_display_close (MetaDisplay *display,
                    guint32      timestamp)
{
  g_assert (display != NULL);
  g_assert (display == the_display);

  if (display->closing != 0)
    {
      /* The display's already been closed. */
      return;
    }

  display->closing += 1;

  meta_prefs_remove_listener (prefs_changed_callback, display);

  meta_display_remove_autoraise_callback (display);

  g_clear_object (&display->gesture_tracker);

  if (display->focus_timeout_id)