layer_shell: set layer of existing surface

include/wlr/types/wlr_layer_shell_v1.h

@@ -54,6 +54,7 @@ struct wlr_layer_surface_v1_state {
 	bool keyboard_interactive;
 	uint32_t desired_width, desired_height;
 	uint32_t actual_width, actual_height;
+	enum zwlr_layer_shell_v1_layer layer;
 };
 
 struct wlr_layer_surface_v1_configure {
@@ -71,7 +72,6 @@ struct wlr_layer_surface_v1 {
 	struct wl_list popups; // wlr_xdg_popup::link
 
 	char *namespace;
-	enum zwlr_layer_shell_v1_layer layer;
 
 	bool added, configured, mapped, closed;
 	uint32_t configure_serial;

protocol/wlr-layer-shell-unstable-v1.xml

@@ -25,7 +25,7 @@
     THIS SOFTWARE.
   </copyright>
 
-  <interface name="zwlr_layer_shell_v1" version="1">
+  <interface name="zwlr_layer_shell_v1" version="2">
     <description summary="create surfaces that are layers of the desktop">
       Clients can use this interface to assign the surface_layer role to
       wl_surfaces. Such surfaces are assigned to a "layer" of the output and
@@ -84,7 +84,7 @@
     </enum>
   </interface>
 
-  <interface name="zwlr_layer_surface_v1" version="1">
+  <interface name="zwlr_layer_surface_v1" version="2">
     <description summary="layer metadata interface">
       An interface that may be implemented by a wl_surface, for surfaces that
       are designed to be rendered as a layer of a stacked desktop-like
@@ -231,6 +231,13 @@
       </description>
     </request>
 
+    <request name="set_layer" since="2">
+      <description summary="change the layer of the surface">
+        Change the layer that the surface is rendered on.
+      </description>
+      <arg name="layer" type="uint" enum="layer" summary="layer to move this surface to"/>
+    </request>
+
     <event name="configure">
       <description summary="suggest a surface change">
         The configure event asks the client to resize its surface.

types/wlr_layer_shell_v1.c

@@ -173,6 +173,22 @@ static void layer_surface_handle_get_popup(struct wl_client *client,
 	wlr_signal_emit_safe(&parent->events.new_popup, popup);
 }
 
+static void layer_surface_set_layer(struct wl_client *client,
+		struct wl_resource *surface_resource, uint32_t layer) {
+	struct wlr_layer_surface_v1 *surface =
+			layer_surface_from_resource(surface_resource);
+	if (!surface) {
+		return;
+	}
+	if (layer > ZWLR_LAYER_SHELL_V1_LAYER_OVERLAY) {
+		wl_resource_post_error(surface->resource,
+				ZWLR_LAYER_SHELL_V1_ERROR_INVALID_LAYER,
+				"Invalid layer %d", layer);
+		return;
+	}
+	surface->client_pending.layer = layer;
+}
+
 static const struct zwlr_layer_surface_v1_interface layer_surface_implementation = {
 	.destroy = resource_handle_destroy,
 	.ack_configure = layer_surface_handle_ack_configure,
@@ -182,6 +198,7 @@ static const struct zwlr_layer_surface_v1_interface layer_surface_implementation
 	.set_margin = layer_surface_handle_set_margin,
 	.set_keyboard_interactivity = layer_surface_handle_set_keyboard_interactivity,
 	.get_popup = layer_surface_handle_get_popup,
+	.set_layer = layer_surface_set_layer,
 };
 
 static void layer_surface_unmap(struct wlr_layer_surface_v1 *surface) {
@@ -315,6 +332,7 @@ static void layer_surface_role_commit(struct wlr_surface *wlr_surface) {
 		surface->client_pending.keyboard_interactive;
 	surface->current.desired_width = surface->client_pending.desired_width;
 	surface->current.desired_height = surface->client_pending.desired_height;
+	surface->current.layer = surface->client_pending.layer;
 
 	if (!surface->added) {
 		surface->added = true;
@@ -375,7 +393,7 @@ static void layer_shell_handle_get_layer_surface(struct wl_client *wl_client,
 	if (output_resource) {
 		surface->output = wlr_output_from_resource(output_resource);
 	}
-	surface->layer = layer;
+	surface->current.layer = surface->client_pending.layer = layer;
 	if (layer > ZWLR_LAYER_SHELL_V1_LAYER_OVERLAY) {
 		free(surface);
 		wl_resource_post_error(client_resource,