demo: cube: Process destroy window

Demo was not exiting cleanly when the window close button
was clicked.
Found this solution on-line:
http://lists.freedesktop.org/pipermail/xcb/2010-December/006713.html

1 files changed, 22 insertions, 1 deletions

diff --git a/demos/cube.c b/demos/cube.c
index e3f3c45d..923b8a8d 100644
--- a/demos/cube.c
+++ b/demos/cube.c
@@ -260,6 +260,7 @@ struct demo {
     XGL_CMD_BUFFER cmd;
 
     xcb_window_t window;
+    xcb_intern_atom_reply_t *atom_wm_delete_window;
 
     bool quit;
     XGL_UINT current_buffer;
@@ -1136,10 +1137,17 @@ static void demo_prepare(struct demo *demo)
 static void demo_handle_event(struct demo *demo,
                               const xcb_generic_event_t *event)
 {
-    switch (event->response_type & 0x7f) {
+    u_int8_t event_code = event->response_type & 0x7f;
+    switch (event_code) {
     case XCB_EXPOSE:
         demo_draw(demo);
         break;
+    case XCB_CLIENT_MESSAGE:
+        if((*(xcb_client_message_event_t*)event).data.data32[0] ==
+           (*demo->atom_wm_delete_window).atom) {
+            demo->quit = true;
+        }
+        break;
     case XCB_KEY_RELEASE:
         {
             const xcb_key_release_event_t *key =
@@ -1209,6 +1217,19 @@ static void demo_create_window(struct demo *demo)
             demo->screen->root_visual,
             value_mask, value_list);
 
+    /* Magic code that will send notification when window is destroyed */
+    xcb_intern_atom_cookie_t cookie = xcb_intern_atom(demo->connection, 1, 12,
+                                                      "WM_PROTOCOLS");
+    xcb_intern_atom_reply_t* reply = xcb_intern_atom_reply(demo->connection, cookie, 0);
+
+    xcb_intern_atom_cookie_t cookie2 = xcb_intern_atom(demo->connection, 0, 16, "WM_DELETE_WINDOW");
+    demo->atom_wm_delete_window = xcb_intern_atom_reply(demo->connection, cookie2, 0);
+
+    xcb_change_property(demo->connection, XCB_PROP_MODE_REPLACE,
+                        demo->window, (*reply).atom, 4, 32, 1,
+                        &(*demo->atom_wm_delete_window).atom);
+    free(reply);
+
     xcb_map_window(demo->connection, demo->window);
 }