xwayland: Fix a race condition when setting up input devices

The compositor may send us wl_seat and its capabilities before sending
e.g. relative_pointer_manager or pointer_gesture interfaces. This would
result in devices being created in capabilities handler, but listeners
not, because the interfaces weren't available at the time. So we
manually attempt to setup listeners again.

Signed-off-by: Povilas Kanapickas <povilas@radix.lt>

hw/xwayland/xwayland-input.c

@@ -1469,6 +1469,18 @@ release_pointer(struct xwl_seat *xwl_seat)
 
 static void
 init_relative_pointer(struct xwl_seat *xwl_seat)
+{
+    if (xwl_seat->relative_pointer == NULL) {
+        xwl_seat->relative_pointer =
+            add_device(xwl_seat, "xwayland-relative-pointer",
+                       xwl_pointer_proc_relative);
+        ActivateDevice(xwl_seat->relative_pointer, TRUE);
+    }
+    enable_device(xwl_seat, xwl_seat->relative_pointer);
+}
+
+static void
+init_relative_pointer_listener(struct xwl_seat *xwl_seat)
 {
     struct zwp_relative_pointer_manager_v1 *relative_pointer_manager =
         xwl_seat->xwl_screen->relative_pointer_manager;
@@ -1481,14 +1493,6 @@ init_relative_pointer(struct xwl_seat *xwl_seat)
                                              &relative_pointer_listener,
                                              xwl_seat);
     }
-
-    if (xwl_seat->relative_pointer == NULL) {
-        xwl_seat->relative_pointer =
-            add_device(xwl_seat, "xwayland-relative-pointer",
-                       xwl_pointer_proc_relative);
-        ActivateDevice(xwl_seat->relative_pointer, TRUE);
-    }
-    enable_device(xwl_seat, xwl_seat->relative_pointer);
 }
 
 static void
@@ -1505,11 +1509,23 @@ release_relative_pointer(struct xwl_seat *xwl_seat)
 
 static void
 init_pointer_gestures_device(struct xwl_seat *xwl_seat)
+{
+    if (xwl_seat->pointer_gestures == NULL) {
+        xwl_seat->pointer_gestures =
+            add_device(xwl_seat, "xwayland-pointer-gestures",
+                       xwl_pointer_proc_pointer_gestures);
+        ActivateDevice(xwl_seat->pointer_gestures, TRUE);
+    }
+    enable_device(xwl_seat, xwl_seat->pointer_gestures);
+}
+
+static void
+init_pointer_gestures_listener(struct xwl_seat *xwl_seat)
 {
     struct zwp_pointer_gestures_v1 *pointer_gestures =
             xwl_seat->xwl_screen->pointer_gestures;
 
-    if (pointer_gestures) {
+    if (pointer_gestures && !xwl_seat->wp_pointer_gesture_swipe) {
         xwl_seat->wp_pointer_gesture_swipe =
                 zwp_pointer_gestures_v1_get_swipe_gesture(pointer_gestures,
                                                           xwl_seat->wl_pointer);
@@ -1518,7 +1534,9 @@ init_pointer_gestures_device(struct xwl_seat *xwl_seat)
         zwp_pointer_gesture_swipe_v1_add_listener(xwl_seat->wp_pointer_gesture_swipe,
                                                   &pointer_gesture_swipe_listener,
                                                   xwl_seat);
+    }
 
+    if (pointer_gestures && !xwl_seat->wp_pointer_gesture_pinch) {
         xwl_seat->wp_pointer_gesture_pinch =
                 zwp_pointer_gestures_v1_get_pinch_gesture(pointer_gestures,
                                                           xwl_seat->wl_pointer);
@@ -1528,14 +1546,6 @@ init_pointer_gestures_device(struct xwl_seat *xwl_seat)
                                                   &pointer_gesture_pinch_listener,
                                                   xwl_seat);
     }
-
-    if (xwl_seat->pointer_gestures == NULL) {
-        xwl_seat->pointer_gestures =
-            add_device(xwl_seat, "xwayland-pointer-gestures",
-                       xwl_pointer_proc_pointer_gestures);
-        ActivateDevice(xwl_seat->pointer_gestures, TRUE);
-    }
-    enable_device(xwl_seat, xwl_seat->pointer_gestures);
 }
 
 static void
@@ -1627,7 +1637,9 @@ seat_handle_capabilities(void *data, struct wl_seat *seat,
     if (caps & WL_SEAT_CAPABILITY_POINTER && xwl_seat->wl_pointer == NULL) {
         init_pointer(xwl_seat);
         init_relative_pointer(xwl_seat);
+        init_relative_pointer_listener(xwl_seat);
         init_pointer_gestures_device(xwl_seat);
+        init_pointer_gestures_listener(xwl_seat);
     } else if (!(caps & WL_SEAT_CAPABILITY_POINTER) && xwl_seat->wl_pointer) {
         release_pointer(xwl_seat);
         release_relative_pointer(xwl_seat);
@@ -2812,6 +2824,34 @@ init_keyboard_grab(struct xwl_screen *xwl_screen,
     }
 }
 
+/* The compositor may send us wl_seat and its capabilities before sending e.g.
+   relative_pointer_manager or pointer_gesture interfaces. This would result in
+   devices being created in capabilities handler, but listeners not, because
+   the interfaces weren't available at the time. So we manually attempt to setup
+   listeners again.
+*/
+static void
+maybe_init_relative_pointer_listeners_after_capabilities(struct xwl_screen* xwl_screen)
+{
+    struct xwl_seat *xwl_seat;
+    xorg_list_for_each_entry(xwl_seat, &xwl_screen->seat_list, link) {
+        if (xwl_seat->wl_pointer) {
+            init_relative_pointer_listener(xwl_seat);
+        }
+    }
+}
+
+static void
+maybe_init_pointer_gesture_listeners_after_capabilities(struct xwl_screen* xwl_screen)
+{
+    struct xwl_seat *xwl_seat;
+    xorg_list_for_each_entry(xwl_seat, &xwl_screen->seat_list, link) {
+        if (xwl_seat->wl_pointer) {
+            init_pointer_gestures_listener(xwl_seat);
+        }
+    }
+}
+
 static void
 input_handler(void *data, struct wl_registry *registry, uint32_t id,
               const char *interface, uint32_t version)
@@ -2823,10 +2863,12 @@ input_handler(void *data, struct wl_registry *registry, uint32_t id,
         xwl_screen->expecting_event++;
     } else if (strcmp(interface, "zwp_relative_pointer_manager_v1") == 0) {
         init_relative_pointer_manager(xwl_screen, id, version);
+        maybe_init_relative_pointer_listeners_after_capabilities(xwl_screen);
     } else if (strcmp(interface, "zwp_pointer_constraints_v1") == 0) {
         init_pointer_constraints(xwl_screen, id, version);
     } else if (strcmp(interface, "zwp_pointer_gestures_v1") == 0) {
         init_pointer_gestures(xwl_screen, id, version);
+        maybe_init_pointer_gesture_listeners_after_capabilities(xwl_screen);
     } else if (strcmp(interface, "zwp_tablet_manager_v2") == 0) {
         init_tablet_manager(xwl_screen, id, version);
     } else if (strcmp(interface, "zwp_xwayland_keyboard_grab_manager_v1") == 0) {