Handle FocusIn events generated by clients and update decoration accordingly (Thanks mseed)

src/handlers.c

@@ -129,6 +129,10 @@ void handle_event(int type, xcb_generic_event_t *event) {
             handle_mapping_notify(NULL, conn, (xcb_mapping_notify_event_t*)event);
             break;
 
+        case XCB_FOCUS_IN:
+            handle_focus_in(NULL, conn, (xcb_focus_in_event_t*)event);
+            break;
+
         case XCB_PROPERTY_NOTIFY:
             DLOG("Property notify\n");
             xcb_property_notify_event_t *e = (xcb_property_notify_event_t*)event;
@@ -1023,3 +1027,34 @@ int handle_clientleader_change(void *data, xcb_connection_t *conn, uint8_t state
 
     return 1;
 }
+
+/*
+ * Handles FocusIn events which are generated by clients (i3’s focus changes
+ * don’t generate FocusIn events due to a different EventMask) and updates the
+ * decorations accordingly.
+ *
+ */
+int handle_focus_in(void *data, xcb_connection_t *conn, xcb_focus_in_event_t *event) {
+    DLOG("focus change in, for window 0x%08x\n", event->event);
+    Con *con;
+    if ((con = con_by_window_id(event->event)) == NULL || con->window == NULL)
+        return 1;
+    DLOG("That is con %p / %s\n", con, con->name);
+
+    if (event->detail == XCB_NOTIFY_DETAIL_POINTER) {
+        DLOG("notify detail is pointer, ignoring this event\n");
+        return 1;
+    }
+
+    if (focused_id == event->event) {
+        DLOG("focus matches the currently focused window, not doing anything\n");
+        return 1;
+    }
+
+    DLOG("focus is different, updating decorations\n");
+    con_focus(con);
+    /* We update focused_id because we don’t need to set focus again */
+    focused_id = event->event;
+    x_push_changes(croot);
+    return 1;
+}