xwm: let the shells decide the position of X windows

The xwm used to automatically send to Xwayland the position of X windows
when that changed, using the x,y of the primary view of the surface.
This works fine for the desktop shell but less so for others.
This patch adds a 'send_position' vfunc to the weston_shell_client that
the shell will call when it wants to let Xwayland know what the position
of a window is.
The logic used by the desktop-shell for that is exactly the same the xwm
used to have.
Reviewed-by: Derek Foreman <derekf@osg.samsung.com>
Reviewed-by: David Fort <contact@hardening-consulting.com>

desktop-shell/shell.c

@@ -1813,7 +1813,8 @@ send_configure(struct weston_surface *surface, int32_t width, int32_t height)
 }
 
 static const struct weston_shell_client shell_client = {
-	send_configure
+	send_configure,
+	NULL
 };
 
 static void
@@ -3704,12 +3705,6 @@ create_shell_surface(void *shell, struct weston_surface *surface,
 	return create_common_surface(NULL, shell, surface, client);
 }
 
-static struct weston_view *
-get_primary_view(void *shell, struct shell_surface *shsurf)
-{
-	return shsurf->view;
-}
-
 static void
 shell_get_shell_surface(struct wl_client *client,
 			struct wl_resource *resource,
@@ -3995,7 +3990,8 @@ xdg_send_configure(struct weston_surface *surface,
 }
 
 static const struct weston_shell_client xdg_client = {
-	xdg_send_configure
+	xdg_send_configure,
+	NULL
 };
 
 static void
@@ -4119,7 +4115,8 @@ xdg_popup_send_configure(struct weston_surface *surface,
 }
 
 static const struct weston_shell_client xdg_popup_client = {
-	xdg_popup_send_configure
+	xdg_popup_send_configure,
+	NULL
 };
 
 static struct shell_surface *
@@ -5411,6 +5408,27 @@ wake_handler(struct wl_listener *listener, void *data)
 	unlock(shell);
 }
 
+static void
+transform_handler(struct wl_listener *listener, void *data)
+{
+	struct weston_surface *surface = data;
+	struct shell_surface *shsurf = get_shell_surface(surface);
+	struct weston_view *view;;
+	int x, y;
+
+	if (!shsurf || !shsurf->client->send_position)
+		return;
+
+	view = shsurf->view;
+	if (!view || !weston_view_is_mapped(view))
+		return;
+
+	x = view->geometry.x;
+	y = view->geometry.y;
+
+	shsurf->client->send_position(surface, x, y);
+}
+
 static void
 center_on_output(struct weston_view *view, struct weston_output *output)
 {
@@ -6379,6 +6397,7 @@ shell_destroy(struct wl_listener *listener, void *data)
 
 	wl_list_remove(&shell->idle_listener.link);
 	wl_list_remove(&shell->wake_listener.link);
+	wl_list_remove(&shell->transform_listener.link);
 
 	text_backend_destroy(shell->text_backend);
 	input_panel_destroy(shell);
@@ -6520,10 +6539,11 @@ module_init(struct weston_compositor *ec,
 	wl_signal_add(&ec->idle_signal, &shell->idle_listener);
 	shell->wake_listener.notify = wake_handler;
 	wl_signal_add(&ec->wake_signal, &shell->wake_listener);
+	shell->transform_listener.notify = transform_handler;
+	wl_signal_add(&ec->transform_signal, &shell->transform_listener);
 
 	ec->shell_interface.shell = shell;
 	ec->shell_interface.create_shell_surface = create_shell_surface;
-	ec->shell_interface.get_primary_view = get_primary_view;
 	ec->shell_interface.set_toplevel = set_toplevel;
 	ec->shell_interface.set_transient = set_transient;
 	ec->shell_interface.set_fullscreen = shell_interface_set_fullscreen;

desktop-shell/shell.h

@@ -121,6 +121,7 @@ struct desktop_shell {
 
 	struct wl_listener idle_listener;
 	struct wl_listener wake_listener;
+	struct wl_listener transform_listener;
 	struct wl_listener destroy_listener;
 	struct wl_listener show_input_panel_listener;
 	struct wl_listener hide_input_panel_listener;

src/compositor.h

@@ -86,6 +86,7 @@ struct weston_mode {
 
 struct weston_shell_client {
 	void (*send_configure)(struct weston_surface *surface, int32_t width, int32_t height);
+	void (*send_position)(struct weston_surface *surface, int32_t x, int32_t y);
 };
 
 struct weston_shell_interface {
@@ -94,9 +95,6 @@ struct weston_shell_interface {
 	struct shell_surface *(*create_shell_surface)(void *shell,
 						      struct weston_surface *surface,
 						      const struct weston_shell_client *client);
-	struct weston_view *(*get_primary_view)(void *shell,
-						struct shell_surface *shsurf);
-
 	void (*set_toplevel)(struct shell_surface *shsurf);
 
 	void (*set_transient)(struct shell_surface *shsurf,

xwayland/window-manager.c

@@ -145,6 +145,7 @@ struct weston_wm_window {
 	xcb_atom_t type;
 	int width, height;
 	int x, y;
+	bool pos_dirty;
 	int saved_width, saved_height;
 	int decorate;
 	int override_redirect;
@@ -692,6 +693,8 @@ weston_wm_handle_configure_notify(struct weston_wm *wm, xcb_generic_event_t *eve
 
 	window->x = configure_notify->x;
 	window->y = configure_notify->y;
+	window->pos_dirty = false;
+
 	if (window->override_redirect) {
 		window->width = configure_notify->width;
 		window->height = configure_notify->height;
@@ -808,41 +811,6 @@ weston_wm_window_activate(struct wl_listener *listener, void *data)
 
 }
 
-static void
-weston_wm_window_transform(struct wl_listener *listener, void *data)
-{
-	struct weston_surface *surface = data;
-	struct weston_wm_window *window = get_wm_window(surface);
-	struct weston_wm *wm =
-		container_of(listener, struct weston_wm, transform_listener);
-	struct weston_view *view;
-	struct weston_shell_interface *shell_interface =
-		&wm->server->compositor->shell_interface;
-	uint32_t mask, values[2];
-
-	if (!window || !wm || !window->shsurf)
-		return;
-
-	if (!shell_interface->get_primary_view)
-		return;
-
-	view = shell_interface->get_primary_view(shell_interface->shell,
-	                                         window->shsurf);
-
-	if (!view || !weston_view_is_mapped(view))
-		return;
-
-	if (window->x != view->geometry.x ||
-	    window->y != view->geometry.y) {
-		values[0] = view->geometry.x;
-		values[1] = view->geometry.y;
-		mask = XCB_CONFIG_WINDOW_X | XCB_CONFIG_WINDOW_Y;
-
-		xcb_configure_window(wm->conn, window->frame_id, mask, values);
-		xcb_flush(wm->conn);
-	}
-}
-
 #define ICCCM_WITHDRAWN_STATE	0
 #define ICCCM_NORMAL_STATE	1
 #define ICCCM_ICONIC_STATE	3
@@ -1226,6 +1194,7 @@ weston_wm_window_create(struct weston_wm *wm,
 	window->height = height;
 	window->x = x;
 	window->y = y;
+	window->pos_dirty = false;
 
 	geometry_reply = xcb_get_geometry_reply(wm->conn, geometry_cookie, NULL);
 	/* technically we should use XRender and check the visual format's
@@ -2316,9 +2285,6 @@ weston_wm_create(struct weston_xserver *wxs, int fd)
 	wm->activate_listener.notify = weston_wm_window_activate;
 	wl_signal_add(&wxs->compositor->activate_signal,
 		      &wm->activate_listener);
-	wm->transform_listener.notify = weston_wm_window_transform;
-	wl_signal_add(&wxs->compositor->transform_signal,
-		      &wm->transform_listener);
 	wm->kill_listener.notify = weston_wm_kill_client;
 	wl_signal_add(&wxs->compositor->kill_signal,
 		      &wm->kill_listener);
@@ -2347,7 +2313,6 @@ weston_wm_destroy(struct weston_wm *wm)
 	wl_list_remove(&wm->selection_listener.link);
 	wl_list_remove(&wm->activate_listener.link);
 	wl_list_remove(&wm->kill_listener.link);
-	wl_list_remove(&wm->transform_listener.link);
 	wl_list_remove(&wm->create_surface_listener.link);
 
 	free(wm);
@@ -2438,8 +2403,35 @@ send_configure(struct weston_surface *surface, int32_t width, int32_t height)
 				       weston_wm_window_configure, window);
 }
 
+static void
+send_position(struct weston_surface *surface, int32_t x, int32_t y)
+{
+	struct weston_wm_window *window = get_wm_window(surface);
+	struct weston_wm *wm;
+	uint32_t mask, values[2];
+
+	if (!window || !window->wm)
+		return;
+
+	wm = window->wm;
+	/* We use pos_dirty to tell whether a configure message is in flight.
+	 * This is needed in case we send two configure events in a very
+	 * short time, since window->x/y is set in after a roundtrip, hence
+	 * we cannot just check if the current x and y are different. */
+	if (window->x != x || window->y != y || window->pos_dirty) {
+		window->pos_dirty = true;
+		values[0] = x;
+		values[1] = y;
+		mask = XCB_CONFIG_WINDOW_X | XCB_CONFIG_WINDOW_Y;
+
+		xcb_configure_window(wm->conn, window->frame_id, mask, values);
+		xcb_flush(wm->conn);
+	}
+}
+
 static const struct weston_shell_client shell_client = {
-	send_configure
+	send_configure,
+	send_position
 };
 
 static int

xwayland/xwayland.h

@@ -70,7 +70,6 @@ struct weston_wm {
 	xcb_colormap_t colormap;
 	struct wl_listener create_surface_listener;
 	struct wl_listener activate_listener;
-	struct wl_listener transform_listener;
 	struct wl_listener kill_listener;
 	struct wl_list unpaired_window_list;