mutter/clutter/x11/clutter-event-x11.c

/* Clutter.
 * An OpenGL based 'interactive canvas' library.
 *
 * Copyright (C) 2006, 2007, 2008  OpenedHand Ltd
 * Copyright (C) 2009, 2010  Intel Corp.
 *
 * 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 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/>.
 *
 *
 *
 * Authored by:
 *      Matthew Allum <mallum@openedhand.com>
 *      Emmanuele Bassi <ebassi@linux.intel.com>
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "clutter-stage-x11.h"
#include "clutter-backend-x11.h"
#include "clutter-keymap-x11.h"
#include "clutter-x11.h"

#include "../clutter-backend.h"
#include "../clutter-event.h"
#include "../clutter-private.h"
#include "../clutter-debug.h"
#include "../clutter-main.h"

#include "cogl/cogl-internal.h"

#include <string.h>

#include <glib.h>

#ifdef HAVE_XFIXES
#include <X11/extensions/Xfixes.h>
#endif

#include <X11/Xatom.h>

#ifdef HAVE_XINPUT
#include <X11/extensions/XInput.h>
#endif

#ifdef HAVE_XKB
#include <X11/XKBlib.h>
#endif

/* XEMBED protocol support for toolkit embedding */
#define XEMBED_MAPPED                   (1 << 0)
#define MAX_SUPPORTED_XEMBED_VERSION    1

#define XEMBED_EMBEDDED_NOTIFY          0
#define XEMBED_WINDOW_ACTIVATE          1
#define XEMBED_WINDOW_DEACTIVATE        2
#define XEMBED_REQUEST_FOCUS            3
#define XEMBED_FOCUS_IN                 4
#define XEMBED_FOCUS_OUT                5
#define XEMBED_FOCUS_NEXT               6
#define XEMBED_FOCUS_PREV               7
/* 8-9 were used for XEMBED_GRAB_KEY/XEMBED_UNGRAB_KEY */
#define XEMBED_MODALITY_ON              10
#define XEMBED_MODALITY_OFF             11
#define XEMBED_REGISTER_ACCELERATOR     12
#define XEMBED_UNREGISTER_ACCELERATOR   13
#define XEMBED_ACTIVATE_ACCELERATOR     14

static Window ParentEmbedderWin = None;

typedef struct _ClutterEventSource      ClutterEventSource;

struct _ClutterEventSource
{
  GSource source;

  ClutterBackend *backend;
  GPollFD event_poll_fd;
};

struct _ClutterEventX11
{
  /* additional fields for Key events */
  gint key_group;

  guint num_lock_set  : 1;
  guint caps_lock_set : 1;
};

ClutterEventX11 *
_clutter_event_x11_new (void)
{
  return g_slice_new0 (ClutterEventX11);
}

ClutterEventX11 *
_clutter_event_x11_copy (ClutterEventX11 *event_x11)
{
  if (event_x11 != NULL)
    return g_slice_dup (ClutterEventX11, event_x11);

  return NULL;
}

void
_clutter_event_x11_free (ClutterEventX11 *event_x11)
{
  if (event_x11 != NULL)
    g_slice_free (ClutterEventX11, event_x11);
}

static gboolean clutter_event_prepare  (GSource     *source,
                                        gint        *timeout);
static gboolean clutter_event_check    (GSource     *source);
static gboolean clutter_event_dispatch (GSource     *source,
                                        GSourceFunc  callback,
                                        gpointer     user_data);

static GList *event_sources = NULL;

static GSourceFuncs event_funcs = {
  clutter_event_prepare,
  clutter_event_check,
  clutter_event_dispatch,
  NULL
};

static GSource *
clutter_event_source_new (ClutterBackend *backend)
{
  GSource *source = g_source_new (&event_funcs, sizeof (ClutterEventSource));
  ClutterEventSource *event_source = (ClutterEventSource *) source;

#if GLIB_CHECK_VERSION (2, 25, 8)
  g_source_set_name (source, "Clutter X11 Event");
#endif

  event_source->backend = backend;

  return source;
}

static gboolean
check_xpending (ClutterBackend *backend)
{
  return XPending (CLUTTER_BACKEND_X11 (backend)->xdpy);
}

static gboolean
xembed_send_message (ClutterBackendX11 *backend_x11,
                     Window             window,
                     long               message,
                     long               detail,
                     long               data1,
                     long               data2)
{
  XEvent ev;

  memset (&ev, 0, sizeof (ev));

  ev.xclient.type = ClientMessage;
  ev.xclient.window = window;
  ev.xclient.message_type = backend_x11->atom_XEMBED;
  ev.xclient.format = 32;
  ev.xclient.data.l[0] = CurrentTime;
  ev.xclient.data.l[1] = message;
  ev.xclient.data.l[2] = detail;
  ev.xclient.data.l[3] = data1;
  ev.xclient.data.l[4] = data2;

  clutter_x11_trap_x_errors ();

  XSendEvent (backend_x11->xdpy, window, False, NoEventMask, &ev);
  XSync (backend_x11->xdpy, False);

  if (clutter_x11_untrap_x_errors ())
    return False;

  return True;
}

static void
xembed_set_info (ClutterBackendX11 *backend_x11,
                 Window             window,
                 gint               flags)
{
  gint32 list[2];

  list[0] = MAX_SUPPORTED_XEMBED_VERSION;
  list[1] = XEMBED_MAPPED;

  XChangeProperty (backend_x11->xdpy, window,
                   backend_x11->atom_XEMBED_INFO,
                   backend_x11->atom_XEMBED_INFO, 32,
                   PropModeReplace, (unsigned char *) list, 2);
}

void
_clutter_backend_x11_events_init (ClutterBackend *backend)
{
  ClutterBackendX11 *backend_x11 = CLUTTER_BACKEND_X11 (backend);
  GSource *source;
  ClutterEventSource *event_source;
  int connection_number;

  connection_number = ConnectionNumber (backend_x11->xdpy);
  CLUTTER_NOTE (EVENT, "Connection number: %d", connection_number);

  source = backend_x11->event_source = clutter_event_source_new (backend);
  event_source = (ClutterEventSource *) source;
  g_source_set_priority (source, CLUTTER_PRIORITY_EVENTS);

  event_source->event_poll_fd.fd = connection_number;
  event_source->event_poll_fd.events = G_IO_IN;

  event_sources = g_list_prepend (event_sources, event_source);

  g_source_add_poll (source, &event_source->event_poll_fd);
  g_source_set_can_recurse (source, TRUE);
  g_source_attach (source, NULL);
}

void
_clutter_backend_x11_events_uninit (ClutterBackend *backend)
{
  ClutterBackendX11 *backend_x11 = CLUTTER_BACKEND_X11 (backend);

  if (backend_x11->event_source)
    {
      CLUTTER_NOTE (EVENT, "Destroying the event source");

      event_sources = g_list_remove (event_sources,
                                     backend_x11->event_source);

      g_source_destroy (backend_x11->event_source);
      g_source_unref (backend_x11->event_source);
      backend_x11->event_source = NULL;
    }
}

static void
update_last_event_time (ClutterBackendX11 *backend_x11,
                        XEvent            *xevent)
{
  Time current_time = CurrentTime;
  Time last_time = backend_x11->last_event_time;

  switch (xevent->type)
    {
    case KeyPress:
    case KeyRelease:
      current_time = xevent->xkey.time;
      break;

    case ButtonPress:
    case ButtonRelease:
      current_time = xevent->xbutton.time;
      break;

    case MotionNotify:
      current_time = xevent->xmotion.time;
      break;

    case EnterNotify:
    case LeaveNotify:
      current_time = xevent->xcrossing.time;
      break;

    case PropertyNotify:
      current_time = xevent->xproperty.time;
      break;

    default:
      break;
    }

  /* only change the current event time if it's after the previous event
   * time, or if it is at least 30 seconds earlier - in case the system
   * clock was changed
   */
  if ((current_time != CurrentTime) &&
      (current_time > last_time || (last_time - current_time > (30 * 1000))))
    backend_x11->last_event_time = current_time;
}

static void
set_user_time (ClutterBackendX11 *backend_x11,
               Window            *xwindow,
               long               timestamp)
{
  if (timestamp != CLUTTER_CURRENT_TIME)
    {
      XChangeProperty (backend_x11->xdpy, *xwindow,
                       backend_x11->atom_NET_WM_USER_TIME,
                       XA_CARDINAL, 32, PropModeReplace,
                       (unsigned char *) &timestamp, 1);
    }
}

#ifdef HAVE_XINPUT
static void
convert_xdevicekey_to_xkey (XDeviceKeyEvent *xkev,
                            XEvent          *xevent)
{
  xevent->xany.type = xevent->xkey.type = xkev->type;
  xevent->xkey.serial = xkev->serial;
  xevent->xkey.display = xkev->display;
  xevent->xkey.window = xkev->window;
  xevent->xkey.root = xkev->root;
  xevent->xkey.subwindow = xkev->subwindow;
  xevent->xkey.time = xkev->time;
  xevent->xkey.x = xkev->x;
  xevent->xkey.y = xkev->y;
  xevent->xkey.x_root = xkev->x_root;
  xevent->xkey.y_root = xkev->y_root;
  xevent->xkey.state = xkev->state;
  xevent->xkey.keycode = xkev->keycode;
  xevent->xkey.same_screen = xkev->same_screen;
}
#endif /* HAVE_XINPUT */

static inline void
translate_key_event (ClutterBackendX11 *backend_x11,
                     ClutterEvent      *event,
                     XEvent            *xevent)
{
  ClutterEventX11 *event_x11;
  char buffer[256 + 1];
  int n;

  /* KeyEvents have platform specific data associated to them */
  event_x11 = _clutter_event_x11_new ();
  _clutter_event_set_platform_data (event, event_x11);

  event->key.time = xevent->xkey.time;
  event->key.modifier_state = (ClutterModifierType) xevent->xkey.state;
  event->key.hardware_keycode = xevent->xkey.keycode;

  /* keyval is the key ignoring all modifiers ('1' vs. '!') */
  event->key.keyval =
    XKeycodeToKeysym (xevent->xkey.display,
                      xevent->xkey.keycode,
                      0);

  event_x11->key_group =
    _clutter_keymap_x11_get_key_group (backend_x11->keymap,
                                       event->key.modifier_state);
  event_x11->num_lock_set =
    _clutter_keymap_x11_get_num_lock_state (backend_x11->keymap);
  event_x11->caps_lock_set =
    _clutter_keymap_x11_get_caps_lock_state (backend_x11->keymap);

  /* unicode_value is the printable representation */
  n = XLookupString (&xevent->xkey, buffer, sizeof (buffer) - 1, NULL, NULL);

  if (n != NoSymbol)
    {
      event->key.unicode_value = g_utf8_get_char_validated (buffer, n);
      if ((event->key.unicode_value != -1) &&
          (event->key.unicode_value != -2))
        goto out;
    }
  else
    event->key.unicode_value = (gunichar)'\0';

out:
  return;
}

static gboolean
handle_wm_protocols_event (ClutterBackendX11 *backend_x11,
                           Window             window,
                           XEvent            *xevent)
{
  Atom atom = (Atom) xevent->xclient.data.l[0];

  if (atom == backend_x11->atom_WM_DELETE_WINDOW &&
      xevent->xany.window == window)
    {
      /* the WM_DELETE_WINDOW is a request: we do not destroy
       * the window right away, as it might contain vital data;
       * we relay the event to the application and we let it
       * handle the request
       */
      CLUTTER_NOTE (EVENT, "delete window:\txid: %ld",
                    xevent->xclient.window);

      set_user_time (backend_x11,
                     &window,
                     xevent->xclient.data.l[1]);

      return TRUE;
    }
  else if (atom == backend_x11->atom_NET_WM_PING &&
           xevent->xany.window == window)
    {
      XClientMessageEvent xclient = xevent->xclient;

      xclient.window = backend_x11->xwin_root;
      XSendEvent (backend_x11->xdpy, xclient.window,
                  False,
                  SubstructureRedirectMask | SubstructureNotifyMask,
                  (XEvent *) &xclient);
      return FALSE;
    }

  /* do not send any of the WM_PROTOCOLS events to the queue */
  return FALSE;
}

static gboolean
handle_xembed_event (ClutterBackendX11 *backend_x11,
                     XEvent            *xevent)
{
  ClutterActor *stage;

  stage = clutter_stage_get_default ();

  switch (xevent->xclient.data.l[1])
    {
    case XEMBED_EMBEDDED_NOTIFY:
      CLUTTER_NOTE (EVENT, "got XEMBED_EMBEDDED_NOTIFY from %lx",
                    xevent->xclient.data.l[3]);

      ParentEmbedderWin = xevent->xclient.data.l[3];

      clutter_actor_realize (stage);
      clutter_actor_show (stage);

      xembed_set_info (backend_x11,
                       clutter_x11_get_stage_window (CLUTTER_STAGE (stage)),
                       XEMBED_MAPPED);
      break;
    case XEMBED_WINDOW_ACTIVATE:
      CLUTTER_NOTE (EVENT, "got XEMBED_WINDOW_ACTIVATE");
      break;
    case XEMBED_WINDOW_DEACTIVATE:
      CLUTTER_NOTE (EVENT, "got XEMBED_WINDOW_DEACTIVATE");
      break;
    case XEMBED_FOCUS_IN:
      CLUTTER_NOTE (EVENT, "got XEMBED_FOCUS_IN");
      if (ParentEmbedderWin)
        xembed_send_message (backend_x11, ParentEmbedderWin,
                             XEMBED_FOCUS_NEXT,
                             0, 0, 0);
      break;
    default:
      CLUTTER_NOTE (EVENT, "got unknown XEMBED message");
      break;
    }

  /* do not propagate the XEMBED events to the stage */
  return FALSE;
}

static gboolean
event_translate (ClutterBackend *backend,
                 ClutterEvent   *event,
                 XEvent         *xevent)
{
  ClutterBackendX11 *backend_x11;
  ClutterStageX11 *stage_x11;
  ClutterStage *stage;
  ClutterStageWindow *impl;
  ClutterDeviceManager *manager;
  gboolean res, not_yet_handled = FALSE;
  Window xwindow, stage_xwindow;
  ClutterInputDevice *device;

  backend_x11 = CLUTTER_BACKEND_X11 (backend);

  xwindow = xevent->xany.window;

  if (backend_x11->event_filters)
    {
      GSList *node;

      node = backend_x11->event_filters;

      while (node)
        {
          ClutterX11EventFilter *filter = node->data;

          switch (filter->func (xevent, event, filter->data))
            {
            case CLUTTER_X11_FILTER_CONTINUE:
              break;
            case CLUTTER_X11_FILTER_TRANSLATE:
              return TRUE;
            case CLUTTER_X11_FILTER_REMOVE:
              return FALSE;
            default:
              break;
            }

          node = node->next;
        }
    }

  /* Pass the event through Cogl */
  if (_cogl_xlib_handle_event (xevent) == COGL_XLIB_FILTER_REMOVE)
    return FALSE;

  /* Do further processing only on events for the stage window (the x11
   * filters might be getting events for other windows, so do not mess
   * them about.
   */
  stage = clutter_x11_get_stage_from_window (xwindow);
  if (stage == NULL)
    return FALSE;

  impl = _clutter_stage_get_window (stage);
  stage_x11 = CLUTTER_STAGE_X11 (impl);
  stage_xwindow = xwindow; /* clutter_x11_get_stage_window (stage); */

  event->any.stage = stage;

  res = TRUE;

  update_last_event_time (backend_x11, xevent);

  manager = clutter_device_manager_get_default ();

  switch (xevent->type)
    {
    case ConfigureNotify:
      if (!stage_x11->is_foreign_xwin)
        {
          CLUTTER_NOTE (BACKEND, "%s: ConfigureNotify[%x] (%d, %d)",
                        G_STRLOC,
                        (unsigned int) stage_x11->xwin,
                        xevent->xconfigure.width,
                        xevent->xconfigure.height);

          /* Queue a relayout - we want glViewport to be called
           * with the correct values, and this is done in ClutterStage
           * via _cogl_onscreen_clutter_backend_set_size ().
           *
           * We queue a relayout, because if this ConfigureNotify is
           * in response to a size we set in the application, the
           * set_size above is essentially a null-op.
           *
           * Make sure we do this only when the size has changed,
           * otherwise we end up relayouting on window moves.
           */
          if ((stage_x11->state & CLUTTER_STAGE_STATE_FULLSCREEN) ||
              (stage_x11->xwin_width != xevent->xconfigure.width) ||
              (stage_x11->xwin_height != xevent->xconfigure.height))
            {
              clutter_actor_queue_relayout (CLUTTER_ACTOR (stage));
            }

          /* If we're fullscreened, we want these variables to
           * represent the size of the window before it was set
           * to fullscreen.
           */
          if (!(stage_x11->state & CLUTTER_STAGE_STATE_FULLSCREEN))
            {
              stage_x11->xwin_width = xevent->xconfigure.width;
              stage_x11->xwin_height = xevent->xconfigure.height;
            }

          clutter_actor_set_size (CLUTTER_ACTOR (stage),
                                  xevent->xconfigure.width,
                                  xevent->xconfigure.height);

          CLUTTER_UNSET_PRIVATE_FLAGS (stage_x11->wrapper,
                                       CLUTTER_STAGE_IN_RESIZE);

          /* the resize process is complete, so we can ask the stage
           * to set up the GL viewport with the new size
           */
          clutter_stage_ensure_viewport (stage);
        }
      res = FALSE;
      break;

    case PropertyNotify:
      if (xevent->xproperty.atom == backend_x11->atom_NET_WM_STATE &&
          xevent->xproperty.window == stage_xwindow &&
          !stage_x11->is_foreign_xwin)
        {
          Atom     type;
          gint     format;
          gulong   n_items, bytes_after;
          guchar  *data = NULL;
          gboolean fullscreen_set = FALSE;

          clutter_x11_trap_x_errors ();
          XGetWindowProperty (backend_x11->xdpy, stage_xwindow,
                              backend_x11->atom_NET_WM_STATE,
                              0, G_MAXLONG,
                              False, XA_ATOM,
                              &type, &format, &n_items,
                              &bytes_after, &data);
          clutter_x11_untrap_x_errors ();

          if (type != None && data != NULL)
            {
              Atom *atoms = (Atom *) data;
              gulong i;
              gboolean is_fullscreen = FALSE;

              for (i = 0; i < n_items; i++)
                {
                  if (atoms[i] == backend_x11->atom_NET_WM_STATE_FULLSCREEN)
                    fullscreen_set = TRUE;
                }

              is_fullscreen =
                (stage_x11->state & CLUTTER_STAGE_STATE_FULLSCREEN);

              if (fullscreen_set != is_fullscreen)
                {
                  if (fullscreen_set)
                    stage_x11->state |= CLUTTER_STAGE_STATE_FULLSCREEN;
                  else
                    stage_x11->state &= ~CLUTTER_STAGE_STATE_FULLSCREEN;

                  stage_x11->fullscreening = fullscreen_set;

                  event->type = CLUTTER_STAGE_STATE;
                  event->stage_state.changed_mask =
                    CLUTTER_STAGE_STATE_FULLSCREEN;
                  event->stage_state.new_state = stage_x11->state;
                }
              else
                res = FALSE;

              XFree (data);
            }
          else
            res = FALSE;
        }
      else
        res = FALSE;
      break;

    case MapNotify:
      res = FALSE;
      break;

    case UnmapNotify:
      res = FALSE;
      break;

    case FocusIn:
      if (!(stage_x11->state & CLUTTER_STAGE_STATE_ACTIVATED))
        {
          /* TODO: check xevent->xfocus.detail ? */
          stage_x11->state |= CLUTTER_STAGE_STATE_ACTIVATED;

          event->type = CLUTTER_STAGE_STATE;
          event->stage_state.changed_mask = CLUTTER_STAGE_STATE_ACTIVATED;
          event->stage_state.new_state = stage_x11->state;
        }
      else
        res = FALSE;
      break;

    case FocusOut:
      if (stage_x11->state & CLUTTER_STAGE_STATE_ACTIVATED)
        {
          stage_x11->state &= ~CLUTTER_STAGE_STATE_ACTIVATED;

          event->type = CLUTTER_STAGE_STATE;
          event->stage_state.changed_mask = CLUTTER_STAGE_STATE_ACTIVATED;
          event->stage_state.new_state = stage_x11->state;
        }
      else
        res = FALSE;
      break;

    case Expose:
      {
        CLUTTER_NOTE (MULTISTAGE, "expose for stage: %p, redrawing", stage);
        clutter_actor_queue_redraw (CLUTTER_ACTOR (stage));
        res = FALSE;
      }
      break;
    case DestroyNotify:
      CLUTTER_NOTE (EVENT, "destroy notify:\txid: %ld",
                    xevent->xdestroywindow.window);
      if (xevent->xdestroywindow.window == stage_xwindow &&
          !stage_x11->is_foreign_xwin)
        event->type = event->any.type = CLUTTER_DESTROY_NOTIFY;
      else
        res = FALSE;
      break;

    case ClientMessage:
      CLUTTER_NOTE (EVENT, "client message");

      event->type = event->any.type = CLUTTER_CLIENT_MESSAGE;

      if (xevent->xclient.message_type == backend_x11->atom_XEMBED)
        res = handle_xembed_event (backend_x11, xevent);
      else if (xevent->xclient.message_type == backend_x11->atom_WM_PROTOCOLS)
        {
          res = handle_wm_protocols_event (backend_x11, stage_xwindow, xevent);
          event->type = event->any.type = CLUTTER_DELETE;
        }
      break;

    case KeyPress:
      event->key.type = event->type = CLUTTER_KEY_PRESS;
      event->key.device =
        clutter_device_manager_get_core_device (manager,
                                                CLUTTER_KEYBOARD_DEVICE);

      translate_key_event (backend_x11, event, xevent);

      set_user_time (backend_x11, &xwindow, xevent->xkey.time);
      break;
              
    case KeyRelease:
      /* old-style X11 terminals require that even modern X11 send
       * KeyPress/KeyRelease pairs when auto-repeating. for this
       * reason modern(-ish) API like XKB has a way to detect
       * auto-repeat and do a single KeyRelease at the end of a
       * KeyPress sequence.
       *
       * this check emulates XKB's detectable auto-repeat; we peek
       * the next event and check if it's a KeyPress for the same key
       * and timestamp - and then ignore it if it matches the
       * KeyRelease
       *
       * if we have XKB, and autorepeat is enabled, then this becomes
       * a no-op
       */
      if (!backend_x11->have_xkb_autorepeat && XPending (xevent->xkey.display))
        {
          XEvent next_event;

          XPeekEvent (xevent->xkey.display, &next_event);

          if (next_event.type == KeyPress &&
              next_event.xkey.keycode == xevent->xkey.keycode &&
              next_event.xkey.time == xevent->xkey.time)
            {
              res = FALSE;
              break;
            }
        }

      event->key.type = event->type = CLUTTER_KEY_RELEASE;
      event->key.device =
        clutter_device_manager_get_core_device (manager,
                                                CLUTTER_KEYBOARD_DEVICE);

      translate_key_event (backend_x11, event, xevent);
      break;

    default:
      /* ignore every other event */
      not_yet_handled = TRUE;
      break;
    }

  /* Input device event handling.. */
  if (not_yet_handled)
    {
      device = clutter_device_manager_get_core_device (manager,
                                                       CLUTTER_POINTER_DEVICE);

      /* Regular X event */
      switch (xevent->type)
        {
        case ButtonPress:
          switch (xevent->xbutton.button)
            {
            case 4: /* up */
            case 5: /* down */
            case 6: /* left */
            case 7: /* right */
              event->scroll.type = event->type = CLUTTER_SCROLL;

              if (xevent->xbutton.button == 4)
                event->scroll.direction = CLUTTER_SCROLL_UP;
              else if (xevent->xbutton.button == 5)
                event->scroll.direction = CLUTTER_SCROLL_DOWN;
              else if (xevent->xbutton.button == 6)
                event->scroll.direction = CLUTTER_SCROLL_LEFT;
              else
                event->scroll.direction = CLUTTER_SCROLL_RIGHT;

              event->scroll.time = xevent->xbutton.time;
              event->scroll.x = xevent->xbutton.x;
              event->scroll.y = xevent->xbutton.y;
              event->scroll.modifier_state = xevent->xbutton.state;
              event->scroll.device = device;
              break;

            default:
              event->button.type = event->type = CLUTTER_BUTTON_PRESS;
              event->button.time = xevent->xbutton.time;
              event->button.x = xevent->xbutton.x;
              event->button.y = xevent->xbutton.y;
              event->button.modifier_state = xevent->xbutton.state;
              event->button.button = xevent->xbutton.button;
              event->button.device = device;
              break;
            }

          set_user_time (backend_x11, &xwindow, event->button.time);

          res = TRUE;
          break;

        case ButtonRelease:
          /* scroll events don't have a corresponding release */
          if (xevent->xbutton.button == 4 ||
              xevent->xbutton.button == 5 ||
              xevent->xbutton.button == 6 ||
              xevent->xbutton.button == 7)
            {
              res = FALSE;
              goto out;
            }

          event->button.type = event->type = CLUTTER_BUTTON_RELEASE;
          event->button.time = xevent->xbutton.time;
          event->button.x = xevent->xbutton.x;
          event->button.y = xevent->xbutton.y;
          event->button.modifier_state = xevent->xbutton.state;
          event->button.button = xevent->xbutton.button;
          event->button.device = device;

          res = TRUE;
          break;

        case MotionNotify:
          event->motion.type = event->type = CLUTTER_MOTION;
          event->motion.time = xevent->xmotion.time;
          event->motion.x = xevent->xmotion.x;
          event->motion.y = xevent->xmotion.y;
          event->motion.modifier_state = xevent->xmotion.state;
          event->motion.device = device;

          res = TRUE;
          break;

        case EnterNotify:
          /* we know that we are entering the stage here */
          _clutter_input_device_set_stage (device, stage);
          CLUTTER_NOTE (EVENT, "Entering the stage");

          /* Convert enter notifies to motion events because X
             doesn't emit the corresponding motion notify */
          event->motion.type = event->type = CLUTTER_MOTION;
          event->motion.time = xevent->xcrossing.time;
          event->motion.x = xevent->xcrossing.x;
          event->motion.y = xevent->xcrossing.y;
          event->motion.modifier_state = xevent->xcrossing.state;
          event->motion.source = CLUTTER_ACTOR (stage);
          event->motion.device = device;

          res = TRUE;
          break;

        case LeaveNotify:
          if (device->stage == NULL)
            {
              CLUTTER_NOTE (EVENT,
                            "Discarding LeaveNotify for ButtonRelease "
                            "event off-stage");
              res = FALSE;
              goto out;
            }

          /* we know that we are leaving the stage here */
          _clutter_input_device_set_stage (device, NULL);
          CLUTTER_NOTE (EVENT, "Leaving the stage (time:%u)",
                        event->crossing.time);

          event->crossing.type = event->type = CLUTTER_LEAVE;
          event->crossing.time = xevent->xcrossing.time;
          event->crossing.x = xevent->xcrossing.x;
          event->crossing.y = xevent->xcrossing.y;
          event->crossing.source = CLUTTER_ACTOR (stage);
          event->crossing.device = device;
          res = TRUE;
          break;

        default:
          res = FALSE;
          break;
        }
    }

    /* XInput fun...*/
  if (!res && clutter_x11_has_xinput ())
    {
#ifdef HAVE_XINPUT
      int *ev_types = backend_x11->event_types;
      int button_press, button_release;
      int key_press, key_release;
      int motion_notify;

      button_press   = ev_types[CLUTTER_X11_XINPUT_BUTTON_PRESS_EVENT];
      button_release = ev_types[CLUTTER_X11_XINPUT_BUTTON_RELEASE_EVENT];
      motion_notify  = ev_types[CLUTTER_X11_XINPUT_MOTION_NOTIFY_EVENT];
      key_press      = ev_types[CLUTTER_X11_XINPUT_KEY_PRESS_EVENT];
      key_release    = ev_types[CLUTTER_X11_XINPUT_KEY_RELEASE_EVENT];

      CLUTTER_NOTE (EVENT, "XInput event type: %d", xevent->type);

      if (xevent->type == button_press)
        {
          XDeviceButtonEvent *xbev = (XDeviceButtonEvent *) xevent;

          device = _clutter_x11_get_device_for_xid (xbev->deviceid);
          _clutter_input_device_set_stage (device, stage);

          CLUTTER_NOTE (EVENT,
                        "XI ButtonPress for %li ('%s') at %d, %d",
                        xbev->deviceid,
                        device->device_name,
                        xbev->x,
                        xbev->y);

          switch (xbev->button)
            {
            case 4:
            case 5:
            case 6:
            case 7:
              event->scroll.type = event->type = CLUTTER_SCROLL;

              if (xbev->button == 4)
                event->scroll.direction = CLUTTER_SCROLL_UP;
              else if (xbev->button == 5)
                event->scroll.direction = CLUTTER_SCROLL_DOWN;
              else if (xbev->button == 6)
                event->scroll.direction = CLUTTER_SCROLL_LEFT;
              else
                event->scroll.direction = CLUTTER_SCROLL_RIGHT;

              event->scroll.time = xbev->time;
              event->scroll.x = xbev->x;
              event->scroll.y = xbev->y;
              event->scroll.modifier_state = xbev->state;
              event->scroll.device = device;
              break;

            default:
              event->button.type = event->type = CLUTTER_BUTTON_PRESS;
              event->button.time = xbev->time;
              event->button.x = xbev->x;
              event->button.y = xbev->y;
              event->button.modifier_state = xbev->state;
              event->button.button = xbev->button;
              event->button.device = device;
              break;
            }

          set_user_time (backend_x11, &xwindow, xbev->time);

          res = TRUE;
        }
      else if (xevent->type == button_release)
        {
          XDeviceButtonEvent *xbev = (XDeviceButtonEvent *)xevent;

          device = _clutter_x11_get_device_for_xid (xbev->deviceid);
          _clutter_input_device_set_stage (device, stage);

          CLUTTER_NOTE (EVENT, "XI ButtonRelease for %li ('%s') at %d, %d",
                        xbev->deviceid,
                        device->device_name,
                        xbev->x,
                        xbev->y);

          /* scroll events don't have a corresponding release */
          if (xbev->button == 4 ||
              xbev->button == 5 ||
              xbev->button == 6 ||
              xbev->button == 7)
            {
              res = FALSE;
              goto out;
            }

          event->button.type = event->type = CLUTTER_BUTTON_RELEASE;
          event->button.time = xbev->time;
          event->button.x = xbev->x;
          event->button.y = xbev->y;
          event->button.modifier_state = xbev->state;
          event->button.button = xbev->button;
          event->button.device = device;

          res = TRUE;
        }
      else if (xevent->type == motion_notify)
        {
          XDeviceMotionEvent *xmev = (XDeviceMotionEvent *)xevent;

          device = _clutter_x11_get_device_for_xid (xmev->deviceid);
          _clutter_input_device_set_stage (device, stage);

          CLUTTER_NOTE (EVENT, "XI Motion for %li ('%s') at %d, %d",
                        xmev->deviceid,
                        device->device_name,
                        xmev->x,
                        xmev->y);

          event->motion.type = event->type = CLUTTER_MOTION;
          event->motion.time = xmev->time;
          event->motion.x = xmev->x;
          event->motion.y = xmev->y;
          event->motion.modifier_state = xmev->state;
          event->motion.device = device;

          res = TRUE;
        }
      else if (xevent->type == key_press || xevent->type == key_release)
        {
          /* the XInput 1.x handling of key presses/releases is broken:
           * it makes key repeat, key presses and releases outside the
           * window not generate events even when the window has focus
           */
          XDeviceKeyEvent *xkev = (XDeviceKeyEvent *) xevent;
          XEvent xevent_converted;

          convert_xdevicekey_to_xkey (xkev, &xevent_converted);

          event->key.type = event->type = (xevent->type == key_press)
                                          ? CLUTTER_KEY_PRESS
                                          : CLUTTER_KEY_RELEASE;

          translate_key_event (backend_x11, event, &xevent_converted);

          if (xevent->type == key_press)
            set_user_time (backend_x11, &xwindow, xkev->time);
        }
      else
#endif /* HAVE_XINPUT */
        {
          CLUTTER_NOTE (EVENT, "Uknown Event");
          res = FALSE;
        }
    }

out:
  return res;
}

static void
events_queue (ClutterBackend *backend)
{
  ClutterBackendX11 *backend_x11 = CLUTTER_BACKEND_X11 (backend);
  ClutterBackendX11Class *backend_x11_class =
    CLUTTER_BACKEND_X11_GET_CLASS (backend_x11);
  ClutterEvent      *event;
  Display           *xdisplay = backend_x11->xdpy;
  XEvent             xevent;
  ClutterMainContext  *clutter_context;

  clutter_context = _clutter_context_get_default ();

  while (!clutter_events_pending () && XPending (xdisplay))
    {
      XNextEvent (xdisplay, &xevent);

      if (backend_x11_class->handle_event (backend_x11, &xevent))
        continue;

      event = clutter_event_new (CLUTTER_NOTHING);

      if (event_translate (backend, event, &xevent))
        {
	  /* push directly here to avoid copy of queue_put */
	  g_queue_push_head (clutter_context->events_queue, event);
        }
      else
        clutter_event_free (event);
    }
}

/**
 * clutter_x11_handle_event:
 * @xevent: pointer to XEvent structure
 *
 * This function processes a single X event; it can be used to hook
 * into external X event retrieval (for example that done by GDK).
 *
 * Return value: #ClutterX11FilterReturn. %CLUTTER_X11_FILTER_REMOVE
 *  indicates that Clutter has internally handled the event and the
 *  caller should do no further processing. %CLUTTER_X11_FILTER_CONTINUE
 *  indicates that Clutter is either not interested in the event,
 *  or has used the event to update internal state without taking
 *  any exclusive action. %CLUTTER_X11_FILTER_TRANSLATE will not
 *  occur.
 *
 * Since:  0.8
 */
ClutterX11FilterReturn
clutter_x11_handle_event (XEvent *xevent)
{
  ClutterBackend      *backend;
  ClutterBackendX11Class *backend_x11_class;
  ClutterEvent        *event;
  ClutterMainContext  *clutter_context;
  ClutterX11FilterReturn result;
  gint                 spin = 1;

  /* The return values here are someone approximate; we return
   * CLUTTER_X11_FILTER_REMOVE if a clutter event is
   * generated for the event. This mostly, but not entirely,
   * corresponds to whether other event processing should be
   * excluded. As long as the stage window is not shared with another
   * toolkit it should be safe, and never return
   * %CLUTTER_X11_FILTER_REMOVE when more processing is needed.
   */

  result = CLUTTER_X11_FILTER_CONTINUE;

  clutter_threads_enter ();

  clutter_context = _clutter_context_get_default ();
  backend = clutter_context->backend;
  backend_x11_class = CLUTTER_BACKEND_X11_GET_CLASS (backend);

  /* If the backend just observed the event and didn't want it
   * removed it could return FALSE, so assume that a TRUE return
   * means that our caller should also do no further processing. */
  if (backend_x11_class->handle_event (CLUTTER_BACKEND_X11(backend), xevent))
    return CLUTTER_X11_FILTER_REMOVE;

  event = clutter_event_new (CLUTTER_NOTHING);

  if (event_translate (backend, event, xevent))
    {
      /* push directly here to avoid copy of queue_put */
      result = CLUTTER_X11_FILTER_REMOVE;
      g_queue_push_head (clutter_context->events_queue, event);
    }
  else
    {
      clutter_event_free (event);
      goto out;
    }

  /*
   * Motion events can generate synthetic enter and leave events, so if we
   * are processing a motion event, we need to spin the event loop at least
   * two extra times to pump the enter/leave events through (otherwise they
   * just get pushed down the queue and never processed).
   */
  if (event->type == CLUTTER_MOTION)
    spin += 2;

  while (spin > 0 && (event = clutter_event_get ()))
    {
      /* forward the event into clutter for emission etc. */
      clutter_do_event (event);
      clutter_event_free (event);
      --spin;
    }

 out:
  clutter_threads_leave ();

  return result;
}

static gboolean
clutter_event_prepare (GSource *source,
                       gint    *timeout)
{
  ClutterBackend *backend = ((ClutterEventSource *) source)->backend;
  gboolean retval;

  clutter_threads_enter ();

  *timeout = -1;
  retval = (clutter_events_pending () || check_xpending (backend));

  clutter_threads_leave ();

  return retval;
}

static gboolean
clutter_event_check (GSource *source)
{
  ClutterEventSource *event_source = (ClutterEventSource *) source;
  ClutterBackend *backend = event_source->backend;
  gboolean retval;

  clutter_threads_enter ();

  if (event_source->event_poll_fd.revents & G_IO_IN)
    retval = (clutter_events_pending () || check_xpending (backend));
  else
    retval = FALSE;

  clutter_threads_leave ();

  return retval;
}

static gboolean
clutter_event_dispatch (GSource     *source,
                        GSourceFunc  callback,
                        gpointer     user_data)
{
  ClutterBackend *backend = ((ClutterEventSource *) source)->backend;
  ClutterEvent *event;

  clutter_threads_enter ();

  /*  Grab the event(s), translate and figure out double click.
   *  The push onto queue (stack) if valid.
  */
  events_queue (backend);

  /* Pop an event off the queue if any */
  event = clutter_event_get ();

  if (event)
    {
      /* forward the event into clutter for emission etc. */
      clutter_do_event (event);
      clutter_event_free (event);
    }

  clutter_threads_leave ();

  return TRUE;
}

/**
 * clutter_x11_get_current_event_time:
 *
 * Retrieves the timestamp of the last X11 event processed by
 * Clutter. This might be different from the timestamp returned
 * by clutter_get_current_event_time(), as Clutter may synthesize
 * or throttle events.
 *
 * Return value: a timestamp, in milliseconds
 *
 * Since: 1.0
 */
Time
clutter_x11_get_current_event_time (void)
{
  ClutterBackend *backend = clutter_get_default_backend ();

  return CLUTTER_BACKEND_X11 (backend)->last_event_time;
}

/**
 * clutter_x11_event_get_key_group:
 * @event: a #ClutterEvent of type %CLUTTER_KEY_PRESS or %CLUTTER_KEY_RELEASE
 *
 * Retrieves the group for the modifiers set in @event
 *
 * Return value: the group id
 *
 * Since: 1.4
 */
gint
clutter_x11_event_get_key_group (const ClutterEvent *event)
{
  ClutterEventX11 *event_x11;

  g_return_val_if_fail (event != NULL, 0);
  g_return_val_if_fail (event->type == CLUTTER_KEY_PRESS ||
                        event->type == CLUTTER_KEY_RELEASE, 0);

  event_x11 = _clutter_event_get_platform_data (event);
  if (event_x11 == NULL)
    return 0;

  return event_x11->key_group;
}