wayland: switch to separate queue for wp_image_description_v1

f0883cd fixed the issue that
`set_color_management` would be called on every frame, however it didn't
fix the problem that the first frame would have no image description
set.

Due to a lack of blocking here, events would end up happening in the
following order:

    -> wl_surface.commit()
    -> wp_color_management_surface_v1.set_image_description(...)
    -> wl_surface.commit()
    -> wp_color_management_surface_v1.set_image_description(...)

This would mean setting image description would always lag behind by 1
surface commit. This would effectively result in the first frame never
having any image description set.

Fix this by blocking until the compositor processes what's in the queue
and responds with the ready event so we can set the image description.

Author: llyyr

video/out/wayland_common.c

@@ -2129,6 +2129,7 @@ static void image_description_failed(void *data, struct wp_image_description_v1
                                      uint32_t cause, const char *msg)
 {
     struct vo_wayland_state *wl = data;
+    wl->image_desc_done = true;
     MP_VERBOSE(wl, "Image description failed: %d, %s\n", cause, msg);
     wp_color_management_surface_v1_unset_image_description(wl->color_surface);
     wp_image_description_v1_destroy(image_description);
@@ -2138,6 +2139,7 @@ static void image_description_ready(void *data, struct wp_image_description_v1 *
                                     uint32_t identity)
 {
     struct vo_wayland_state *wl = data;
+    wl->image_desc_done = true;
     wp_color_management_surface_v1_set_image_description(wl->color_surface, image_description, 0);
     MP_TRACE(wl, "Image description set on color surface.\n");
     wp_image_description_v1_destroy(image_description);
@@ -3540,8 +3542,20 @@ static void set_color_management(struct vo_wayland_state *wl)
         wp_image_description_creator_params_v1_set_max_cll(image_creator_params, lrintf(hdr.max_cll));
         wp_image_description_creator_params_v1_set_max_fall(image_creator_params, lrintf(hdr.max_fall));
     }
+
     struct wp_image_description_v1 *image_description = wp_image_description_creator_params_v1_create(image_creator_params);
+    struct wl_event_queue *cm_queue = wl_display_create_queue(wl->display);
+    wl_proxy_set_queue((struct wl_proxy *)image_description, cm_queue);
+    wl->image_desc_done = false;
     wp_image_description_v1_add_listener(image_description, &image_description_listener, wl);
+
+    /* Block here to ensure the compositor is ready to receive the
+     * image_description before we do anything else. */
+    while (wl->image_desc_done == false)
+        if (wl_display_dispatch_queue(wl->display, cm_queue) < 0)
+            break;
+
+    wl_event_queue_destroy(cm_queue);
 #endif
 }
 

video/out/wayland_common.h

@@ -106,6 +106,7 @@ struct vo_wayland_state {
     void *icc_file;
     uint32_t icc_size;
     struct pl_color_space preferred_csp;
+    bool image_desc_done;
 
     /* color-representation */
     struct wp_color_representation_manager_v1 *color_representation_manager;