Implement compositor support for swaylock

This makes swaylock more or less work.

sway/extensions.c

@@ -89,12 +89,27 @@ static void desktop_unlock(struct wl_client *client, struct wl_resource *resourc
 }
 
 static void set_lock_surface(struct wl_client *client, struct wl_resource *resource,
-		struct wl_resource *output, struct wl_resource *surface) {
-	sway_log(L_ERROR, "set_lock_surface is not currently supported");
+		struct wl_resource *_output, struct wl_resource *surface) {
+	swayc_t *output = swayc_by_handle(wlc_handle_from_wl_output_resource(_output));
+	swayc_t *view = swayc_by_handle(wlc_handle_from_wl_surface_resource(surface));
+	if (view && output) {
+		swayc_t *workspace = output->focused;
+		if (!swayc_is_child_of(view, workspace)) {
+			move_container_to(view, workspace);
+		}
+		wlc_view_set_state(view->handle, WLC_BIT_FULLSCREEN, true);
+		workspace->fullscreen = view;
+		desktop_shell.is_locked = true;
+		set_focused_container(view);
+		arrange_windows(view, -1, -1);
+	} else {
+		sway_log(L_ERROR, "Attempted to set lock surface to non-view");
+	}
 }
 
 static void unlock(struct wl_client *client, struct wl_resource *resource) {
 	sway_log(L_ERROR, "unlock is not currently supported");
+	// This isn't really necessary, we just unlock when the client exits.
 }
 
 static void set_grab_surface(struct wl_client *client, struct wl_resource *resource, struct wl_resource *surface) {

sway/handlers.c

@@ -331,6 +331,10 @@ static void handle_view_state_request(wlc_handle view, enum wlc_view_state_bit s
 static bool handle_key(wlc_handle view, uint32_t time, const struct wlc_modifiers *modifiers,
 		uint32_t key, enum wlc_key_state state) {
 
+	if (desktop_shell.is_locked) {
+		return EVENT_PASSTHROUGH;
+	}
+
 	if (locked_view_focus && state == WLC_KEY_STATE_PRESSED) {
 		return EVENT_PASSTHROUGH;
 	}
@@ -383,6 +387,10 @@ static bool handle_key(wlc_handle view, uint32_t time, const struct wlc_modifier
 }
 
 static bool handle_pointer_motion(wlc_handle handle, uint32_t time, const struct wlc_point *origin) {
+	if (desktop_shell.is_locked) {
+		return EVENT_PASSTHROUGH;
+	}
+
 	struct wlc_point new_origin = *origin;
 	// Switch to adjacent output if touching output edge.
 	//

swaylock/main.c

@@ -108,7 +108,6 @@ int main(int argc, char **argv) {
 		if (!window) {
 			sway_abort("Failed to create surfaces.");
 		}
-		lock_set_lock_surface(registry->swaylock, output->output, window->surface);
 		list_add(surfaces, window);
 	}
 
@@ -217,7 +216,17 @@ int main(int argc, char **argv) {
 
 	cairo_surface_destroy(image);
 
-	while (wl_display_dispatch(registry->display) != -1);
+	bool locked = false;
+	while (wl_display_dispatch(registry->display) != -1) {
+		if (!locked) {
+			for (i = 0; i < registry->outputs->length; ++i) {
+				struct output_state *output = registry->outputs->items[i];
+				struct window *window = surfaces->items[i];
+				lock_set_lock_surface(registry->swaylock, output->output, window->surface);
+			}
+			locked = true;
+		}
+	}
 
 	for (i = 0; i < surfaces->length; ++i) {
 		struct window *window = surfaces->items[i];