shell: Don't make desktop_shell background a wl_shell_surface

We don't gain anything from taking a wl_shell_surface in
desktop_surface.set_background, except making wl_shell_surface
gratuitously dependent on wl_shell.  In shell.c we can also handle
backgrounds in their own background_configure function which simplifies
the mapping and placement logic.

clients/desktop-shell.c

@@ -718,10 +718,10 @@ static void
 desktop_shell_configure(void *data,
 			struct desktop_shell *desktop_shell,
 			uint32_t edges,
-			struct wl_shell_surface *shell_surface,
+			struct wl_surface *surface,
 			int32_t width, int32_t height)
 {
-	struct window *window = wl_shell_surface_get_user_data(shell_surface);
+	struct window *window = wl_surface_get_user_data(surface);
 	struct surface *s = window_get_user_data(window);
 
 	s->configure(data, desktop_shell, edges, window, width, height);
@@ -758,9 +758,8 @@ background_create(struct desktop *desktop)
 	memset(background, 0, sizeof *background);
 
 	background->base.configure = background_configure;
-	background->window = window_create(desktop->display);
+	background->window = window_create_custom(desktop->display);
 	background->widget = window_add_widget(background->window, background);
-	window_set_custom(background->window);
 	window_set_user_data(background->window, background);
 	widget_set_redraw_handler(background->widget, background_draw);
 
@@ -877,15 +876,17 @@ int main(int argc, char *argv[])
 				       global_handler, &desktop);
 
 	wl_list_for_each(output, &desktop.outputs, link) {
-		struct wl_shell_surface *s;
+		struct wl_shell_surface *shsurf;
+		struct wl_surface *surface;
 
 		output->panel = panel_create(desktop.display);
-		s = window_get_wl_shell_surface(output->panel->window);
+		shsurf = window_get_wl_shell_surface(output->panel->window);
-		desktop_shell_set_panel(desktop.shell, output->output, s);
+		desktop_shell_set_panel(desktop.shell, output->output, shsurf);
 
 		output->background = background_create(&desktop);
-		s = window_get_wl_shell_surface(output->background->window);
+		surface = window_get_wl_surface(output->background->window);
-		desktop_shell_set_background(desktop.shell, output->output, s);
+		desktop_shell_set_background(desktop.shell,
+					     output->output, surface);
 	}
 
 	busy_surface_create(&desktop);

clients/window.c

@@ -2913,7 +2913,8 @@ static const struct wl_surface_listener surface_listener = {
 };
 
 static struct window *
-window_create_internal(struct display *display, struct window *parent)
+window_create_internal(struct display *display,
+		       struct window *parent, int type)
 {
 	struct window *window;
 
@@ -2926,7 +2927,7 @@ window_create_internal(struct display *display, struct window *parent)
 	window->parent = parent;
 	window->surface = wl_compositor_create_surface(display->compositor);
 	wl_surface_add_listener(window->surface, &surface_listener, window);
-	if (display->shell) {
+	if (type != TYPE_CUSTOM && display->shell) {
 		window->shell_surface =
 			wl_shell_get_shell_surface(display->shell,
 						   window->surface);
@@ -2940,7 +2941,7 @@ window_create_internal(struct display *display, struct window *parent)
 	window->allocation.height = 0;
 	window->saved_allocation = window->allocation;
 	window->transparent = 1;
-	window->type = TYPE_NONE;
+	window->type = type;
 	window->input_region = NULL;
 	window->opaque_region = NULL;
 
@@ -2973,7 +2974,19 @@ window_create(struct display *display)
 {
 	struct window *window;
 
-	window = window_create_internal(display, NULL);
+	window = window_create_internal(display, NULL, TYPE_NONE);
+	if (!window)
+		return NULL;
+
+	return window;
+}
+
+struct window *
+window_create_custom(struct display *display)
+{
+	struct window *window;
+
+	window = window_create_internal(display, NULL, TYPE_CUSTOM);
 	if (!window)
 		return NULL;
 
@@ -2986,11 +2999,11 @@ window_create_transient(struct display *display, struct window *parent,
 {
 	struct window *window;
 
-	window = window_create_internal(parent->display, parent);
+	window = window_create_internal(parent->display,
+					parent, TYPE_TRANSIENT);
 	if (!window)
 		return NULL;
 
-	window->type = TYPE_TRANSIENT;
 	window->x = x;
 	window->y = y;
 
@@ -3123,7 +3136,7 @@ window_show_menu(struct display *display,
 	if (!menu)
 		return;
 
-	window = window_create_internal(parent->display, parent);
+	window = window_create_internal(parent->display, parent, TYPE_MENU);
 	if (!window)
 		return;
 

clients/window.h

@@ -201,6 +201,8 @@ window_create(struct display *display);
 struct window *
 window_create_transient(struct display *display, struct window *parent,
 			int32_t x, int32_t y, uint32_t flags);
+struct window *
+window_create_custom(struct display *display);
 
 typedef void (*menu_func_t)(struct window *window, int index, void *data);
 

protocol/desktop-shell.xml

@@ -9,7 +9,7 @@
 
     <request name="set_background">
       <arg name="output" type="object" interface="wl_output"/>
-      <arg name="surface" type="object" interface="wl_shell_surface"/>
+      <arg name="surface" type="object" interface="wl_surface"/>
     </request>
 
     <request name="set_panel">
@@ -31,7 +31,7 @@
          they'll share the configure event.  -->
     <event name="configure">
       <arg name="edges" type="uint"/>
-      <arg name="surface" type="object" interface="wl_shell_surface"/>
+      <arg name="surface" type="object" interface="wl_surface"/>
       <arg name="width" type="int"/>
       <arg name="height" type="int"/>
     </event>

src/shell.c

@@ -95,7 +95,6 @@ struct desktop_shell {
 	struct shell_surface *lock_surface;
 	struct wl_listener lock_surface_listener;
 
-	struct wl_list backgrounds;
 	struct wl_list panels;
 
 	struct {
@@ -133,7 +132,6 @@ enum shell_surface_type {
 	SHELL_SURFACE_NONE,
 
 	SHELL_SURFACE_PANEL,
-	SHELL_SURFACE_BACKGROUND,
 	SHELL_SURFACE_LOCK,
 	SHELL_SURFACE_SCREENSAVER,
 	SHELL_SURFACE_INPUT_PANEL,
@@ -1229,7 +1227,6 @@ reset_shell_surface_type(struct shell_surface *surface)
 					    surface->saved_y);
 		break;
 	case SHELL_SURFACE_PANEL:
-	case SHELL_SURFACE_BACKGROUND:
 	case SHELL_SURFACE_INPUT_PANEL:
 		wl_list_remove(&surface->link);
 		wl_list_init(&surface->link);
@@ -1294,22 +1291,6 @@ set_surface_type(struct shell_surface *shsurf)
 		}
 		break;
 
-	case SHELL_SURFACE_BACKGROUND:
-		wl_list_for_each(priv, &shell->backgrounds, link) {
-			if (priv->output == shsurf->output) {
-				priv->surface->output = NULL;
-				wl_list_remove(&priv->surface->layer_link);
-				wl_list_remove(&priv->link);
-				break;
-			}
-		}
-
-		wl_list_insert(&shell->backgrounds, &shsurf->link);
-
-		weston_surface_set_position(surface, shsurf->output->x,
-					    shsurf->output->y);
-		break;
-
 	case SHELL_SURFACE_PANEL:
 		wl_list_for_each(priv, &shell->panels, link) {
 			if (priv->output == shsurf->output) {
@@ -1943,21 +1924,54 @@ hide_input_panel(struct desktop_shell *shell, struct shell_surface *surface)
 	weston_compositor_schedule_repaint(surface->surface->compositor);
 }
 
+static void
+background_configure(struct weston_surface *es, int32_t sx, int32_t sy)
+{
+	struct desktop_shell *shell = es->private;
+	struct weston_surface *s;
+
+	wl_list_for_each(s, &shell->background_layer.surface_list, layer_link) {
+		if (s->output == es->output) {
+			s->output = NULL;
+			wl_list_remove(&s->layer_link);
+			s->configure = NULL;
+			break;
+		}
+	}
+
+	weston_surface_configure(es, es->output->x, es->output->y,
+				 es->buffer->width, es->buffer->height);
+
+	if (wl_list_empty(&es->layer_link)) {
+		wl_list_insert(&shell->background_layer.surface_list,
+			       &es->layer_link);
+		weston_surface_assign_output(es);
+	}
+}
+
 static void
 desktop_shell_set_background(struct wl_client *client,
 			     struct wl_resource *resource,
 			     struct wl_resource *output_resource,
 			     struct wl_resource *surface_resource)
 {
-	struct shell_surface *shsurf = surface_resource->data;
+	struct desktop_shell *shell = resource->data;
+	struct weston_surface *surface = surface_resource->data;
 
-	shsurf->next_type = SHELL_SURFACE_BACKGROUND;
+	if (surface->configure) {
-	shsurf->output = output_resource->data;
+		wl_resource_post_error(surface_resource,
+				       WL_DISPLAY_ERROR_INVALID_OBJECT,
+				       "surface role already assigned");
+		return;
+	}
 
+	surface->configure = background_configure;
+	surface->private = shell;
+	surface->output = output_resource->data;
 	desktop_shell_send_configure(resource, 0,
 				     surface_resource,
-				     shsurf->output->current->width,
+				     surface->output->current->width,
-				     shsurf->output->current->height);
+				     surface->output->current->height);
 }
 
 static void
@@ -1972,7 +1986,7 @@ desktop_shell_set_panel(struct wl_client *client,
 	shsurf->output = output_resource->data;
 
 	desktop_shell_send_configure(resource, 0,
-				     surface_resource,
+				     &shsurf->surface->surface.resource,
 				     shsurf->output->current->width,
 				     shsurf->output->current->height);
 }
@@ -2092,7 +2106,6 @@ move_binding(struct wl_seat *seat, uint32_t time, uint32_t button, void *data)
 
 	switch (shsurf->type) {
 		case SHELL_SURFACE_PANEL:
-		case SHELL_SURFACE_BACKGROUND:
 		case SHELL_SURFACE_FULLSCREEN:
 		case SHELL_SURFACE_SCREENSAVER:
 		case SHELL_SURFACE_INPUT_PANEL:
@@ -2122,7 +2135,6 @@ resize_binding(struct wl_seat *seat, uint32_t time, uint32_t button, void *data)
 
 	switch (shsurf->type) {
 		case SHELL_SURFACE_PANEL:
-		case SHELL_SURFACE_BACKGROUND:
 		case SHELL_SURFACE_FULLSCREEN:
 		case SHELL_SURFACE_SCREENSAVER:
 		case SHELL_SURFACE_INPUT_PANEL:
@@ -2170,7 +2182,6 @@ surface_opacity_binding(struct wl_seat *seat, uint32_t time, uint32_t axis,
 		return;
 
 	switch (shsurf->type) {
-		case SHELL_SURFACE_BACKGROUND:
 		case SHELL_SURFACE_SCREENSAVER:
 			return;
 		default:
@@ -2367,7 +2378,6 @@ rotate_binding(struct wl_seat *seat, uint32_t time, uint32_t button,
 
 	switch (surface->type) {
 		case SHELL_SURFACE_PANEL:
-		case SHELL_SURFACE_BACKGROUND:
 		case SHELL_SURFACE_FULLSCREEN:
 		case SHELL_SURFACE_SCREENSAVER:
 		case SHELL_SURFACE_INPUT_PANEL:
@@ -2439,7 +2449,6 @@ activate(struct desktop_shell *shell, struct weston_surface *es,
 	weston_surface_activate(es, seat);
 
 	switch (get_shell_surface_type(es)) {
-	case SHELL_SURFACE_BACKGROUND:
 	case SHELL_SURFACE_PANEL:
 	case SHELL_SURFACE_LOCK:
 	case SHELL_SURFACE_INPUT_PANEL:
@@ -2498,7 +2507,6 @@ click_to_activate_binding(struct wl_seat *seat, uint32_t time, uint32_t button,
 		focus = upper;
 
 	switch (get_shell_surface_type(focus)) {
-		case SHELL_SURFACE_BACKGROUND:
 		case SHELL_SURFACE_SCREENSAVER:
 		case SHELL_SURFACE_INPUT_PANEL:
 			return;
@@ -2685,11 +2693,6 @@ map(struct desktop_shell *shell, struct weston_surface *surface,
 
 	/* surface stacking order, see also activate() */
 	switch (surface_type) {
-	case SHELL_SURFACE_BACKGROUND:
-		/* background always visible, at the bottom */
-		wl_list_insert(&shell->background_layer.surface_list,
-			       &surface->layer_link);
-		break;
 	case SHELL_SURFACE_PANEL:
 		/* panel always on top, hidden while locked */
 		wl_list_insert(&shell->panel_layer.surface_list,
@@ -3418,7 +3421,6 @@ shell_init(struct weston_compositor *ec)
 	ec->shell_interface.move = surface_move;
 	ec->shell_interface.resize = surface_resize;
 
-	wl_list_init(&shell->backgrounds);
 	wl_list_init(&shell->panels);
 	wl_list_init(&shell->screensaver.surfaces);
 	wl_list_init(&shell->input_panel.surfaces);