void Compositor::registerCompositor(QWindow *w)
{
xcb_ewmh_set_wm_cm_owner(&ewmh_, QX11Info::appScreen(), w->winId(), QX11Info::getTimestamp(), 0, 0);
auto wmCmCookie = xcb_ewmh_get_wm_cm_owner_unchecked(&ewmh_, QX11Info::appScreen());
xcb_window_t wmCmOwnerWin = XCB_NONE;
if (!xcb_ewmh_get_wm_cm_owner_reply(&ewmh_, wmCmCookie, &wmCmOwnerWin, Q_NULLPTR)) {
qFatal("Cannot check _NET_WM_CM_Sn");
}
if (wmCmOwnerWin != w->winId()) {
qFatal("Another compositing manager is already running");
}
}
/** Handler for PropertyNotify event meaningful to set the timestamp
* (given in the PropertyNotify event field) when acquiring the
* ownership of _NET_WM_CM_Sn using SetOwner request (as specified in
* ICCCM and EWMH)
*
* \see display_register_cm
* \param event The X PropertyNotify event
*/
void
display_event_set_owner_property(xcb_property_notify_event_t *event)
{
debug("Set _NET_WM_CM_Sn ownership");
/* Set ownership on _NET_WM_CM_Sn giving the Compositing Manager window */
xcb_ewmh_set_wm_cm_owner(&globalconf.ewmh, globalconf.screen_nbr,
globalconf.cm_window, event->time, 0, 0);
/* Send request to check whether the ownership succeeded */
_get_wm_cm_owner_cookie = xcb_ewmh_get_wm_cm_owner_unchecked(&globalconf.ewmh,
globalconf.screen_nbr);
}
void
create_wm_cm_window(xcwm_context_t *context)
{
context->wm_cm_window = xcb_generate_id(context->conn);
printf("Created WM/CM window with XID 0x%08x\n", context->wm_cm_window);
xcb_create_window(context->conn,
XCB_COPY_FROM_PARENT,
context->wm_cm_window,
context->root_window->window_id,
0, 0, 1, 1, 0, /* 1x1 size, no border */
XCB_COPY_FROM_PARENT,
XCB_COPY_FROM_PARENT,
0, NULL);
/* Set the name for the window */
xcb_ewmh_set_wm_name(&context->atoms.ewmh_conn,
context->wm_cm_window,
strlen("xcwm"), "xcwm");
/* Set the atoms for the window */
xcb_ewmh_set_supporting_wm_check(&context->atoms.ewmh_conn,
context->root_window->window_id,
context->wm_cm_window);
xcb_ewmh_set_supporting_wm_check(&context->atoms.ewmh_conn,
context->wm_cm_window,
context->wm_cm_window);
/* Take & announce ownership of the _NET_CM_Sn selection */
xcb_ewmh_set_wm_cm_owner(&context->atoms.ewmh_conn,
context->conn_screen,
context->wm_cm_window,
XCB_CURRENT_TIME,
0, 0);
/* Likewise WM_Sn selection */
/* XXX: Need to do this in a way which complies with ICCCM "Manager Selections" i.e.
use an actual timestamp, so in the case of races, we either acquire selection or don't */
}
