surface: improve role precommit hook

Now the role precommit hook is called before the commit, not on
wl_surface.commit request, and takes a state which is to be applied.

include/types/wlr_xdg_shell.h

@@ -20,7 +20,8 @@ void unmap_xdg_surface(struct wlr_xdg_surface *surface);
 void reset_xdg_surface(struct wlr_xdg_surface *xdg_surface);
 void destroy_xdg_surface(struct wlr_xdg_surface *surface);
 void handle_xdg_surface_commit(struct wlr_surface *wlr_surface);
-void handle_xdg_surface_precommit(struct wlr_surface *wlr_surface);
+void handle_xdg_surface_precommit(struct wlr_surface *wlr_surface,
+	const struct wlr_surface_state *state);
 
 void create_xdg_positioner(struct wlr_xdg_client *client, uint32_t id);
 struct wlr_xdg_positioner_resource *get_xdg_positioner_from_resource(

include/wlr/types/wlr_compositor.h

@@ -73,7 +73,8 @@ struct wlr_surface_state {
 struct wlr_surface_role {
 	const char *name;
 	void (*commit)(struct wlr_surface *surface);
-	void (*precommit)(struct wlr_surface *surface);
+	void (*precommit)(struct wlr_surface *surface,
+		const struct wlr_surface_state *state);
 };
 
 struct wlr_surface_output {

types/wlr_compositor.c

@@ -399,6 +399,10 @@ static void surface_commit_state(struct wlr_surface *surface,
 		struct wlr_surface_state *next) {
 	assert(next->cached_state_locks == 0);
 
+	if (surface->role && surface->role->precommit) {
+		surface->role->precommit(surface, next);
+	}
+
 	bool invalid_buffer = next->committed & WLR_SURFACE_STATE_BUFFER;
 
 	surface->sx += next->dx;
@@ -509,10 +513,6 @@ static void surface_handle_commit(struct wl_client *client,
 
 	wlr_signal_emit_safe(&surface->events.client_commit, NULL);
 
-	if (surface->role && surface->role->precommit) {
-		surface->role->precommit(surface);
-	}
-
 	if (surface->pending.cached_state_locks > 0 || !wl_list_empty(&surface->cached)) {
 		surface_cache_pending(surface);
 	} else {

types/wlr_layer_shell_v1.c

@@ -375,15 +375,15 @@ static void layer_surface_role_commit(struct wlr_surface *wlr_surface) {
 	}
 }
 
-static void layer_surface_role_precommit(struct wlr_surface *wlr_surface) {
+static void layer_surface_role_precommit(struct wlr_surface *wlr_surface,
+		const struct wlr_surface_state *state) {
 	struct wlr_layer_surface_v1 *surface =
 		wlr_layer_surface_v1_from_wlr_surface(wlr_surface);
 	if (surface == NULL) {
 		return;
 	}
 
-	if (wlr_surface->pending.committed & WLR_SURFACE_STATE_BUFFER &&
-			wlr_surface->pending.buffer == NULL) {
+	if (state->committed & WLR_SURFACE_STATE_BUFFER && state->buffer == NULL) {
 		// This is a NULL commit
 		if (surface->configured && surface->mapped) {
 			layer_surface_unmap(surface);

types/wlr_subcompositor.c

@@ -280,15 +280,15 @@ static void subsurface_role_commit(struct wlr_surface *surface) {
 	subsurface_consider_map(subsurface, true);
 }
 
-static void subsurface_role_precommit(struct wlr_surface *surface) {
+static void subsurface_role_precommit(struct wlr_surface *surface,
+		const struct wlr_surface_state *state) {
 	struct wlr_subsurface *subsurface =
 		wlr_subsurface_from_wlr_surface(surface);
 	if (subsurface == NULL) {
 		return;
 	}
 
-	if (surface->pending.committed & WLR_SURFACE_STATE_BUFFER &&
-			surface->pending.buffer == NULL) {
+	if (state->committed & WLR_SURFACE_STATE_BUFFER && state->buffer == NULL) {
 		// This is a NULL commit
 		subsurface_unmap(subsurface);
 	}

types/xdg_shell/wlr_xdg_surface.c

@@ -338,15 +338,15 @@ void handle_xdg_surface_commit(struct wlr_surface *wlr_surface) {
 	}
 }
 
-void handle_xdg_surface_precommit(struct wlr_surface *wlr_surface) {
+void handle_xdg_surface_precommit(struct wlr_surface *wlr_surface,
+		const struct wlr_surface_state *state) {
 	struct wlr_xdg_surface *surface =
 		wlr_xdg_surface_from_wlr_surface(wlr_surface);
 	if (surface == NULL) {
 		return;
 	}
 
-	if (wlr_surface->pending.committed & WLR_SURFACE_STATE_BUFFER &&
-			wlr_surface->pending.buffer == NULL) {
+	if (state->committed & WLR_SURFACE_STATE_BUFFER && state->buffer == NULL) {
 		// This is a NULL commit
 		if (surface->configured && surface->mapped) {
 			unmap_xdg_surface(surface);

xwayland/xwm.c

@@ -852,15 +852,15 @@ static void xwayland_surface_role_commit(struct wlr_surface *wlr_surface) {
 	}
 }
 
-static void xwayland_surface_role_precommit(struct wlr_surface *wlr_surface) {
+static void xwayland_surface_role_precommit(struct wlr_surface *wlr_surface,
+		const struct wlr_surface_state *state) {
 	assert(wlr_surface->role == &xwayland_surface_role);
 	struct wlr_xwayland_surface *surface = wlr_surface->role_data;
 	if (surface == NULL) {
 		return;
 	}
 
-	if (wlr_surface->pending.committed & WLR_SURFACE_STATE_BUFFER &&
-			wlr_surface->pending.buffer == NULL) {
+	if (state->committed & WLR_SURFACE_STATE_BUFFER && state->buffer == NULL) {
 		// This is a NULL commit
 		if (surface->mapped) {
 			wlr_signal_emit_safe(&surface->events.unmap, surface);