[PATCH weston] desktop-shell: Fail if get_xdg_surface is called on an xdg_surface

[Jonas Ådahl]

If a client calls xdg_shell.get_xdg_surface on a surface that is already
an xdg_surface wold, prior to this patch, succeed, but cause weston to
crash later when trying to configure. This patch instead sends a role
error to the client complaining that it already is an xdg_surface.

Note that .._set_role() only fails when changing roles, not when setting
the same role twice.

The same is done for xdg_popup.

Signed-off-by: Jonas Ådahl <jadahl at gmail.com>
---
 desktop-shell/shell.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/desktop-shell/shell.c b/desktop-shell/shell.c
index a7514f7..cc345b5 100644
--- a/desktop-shell/shell.c
+++ b/desktop-shell/shell.c
@@ -3959,6 +3959,14 @@ xdg_get_xdg_surface(struct wl_client *client,
 	struct desktop_shell *shell = sc->shell;
 	struct shell_surface *shsurf;
 
+	if ((shsurf = get_shell_surface(surface)) &&
+	    shell_surface_is_xdg_surface(shsurf)) {
+		wl_resource_post_error(resource, XDG_SHELL_ERROR_ROLE,
+				       "This wl_surface is already an "
+				       "xdg_surface");
+		return;
+	}
+
 	if (weston_surface_set_role(surface, "xdg_surface",
 				    resource, XDG_SHELL_ERROR_ROLE) < 0)
 		return;
@@ -4052,6 +4060,14 @@ xdg_get_xdg_popup(struct wl_client *client,
 	struct weston_surface *parent;
 	struct shell_seat *seat;
 
+	if ((shsurf = get_shell_surface(surface)) &&
+	    shell_surface_is_xdg_popup(shsurf)) {
+		wl_resource_post_error(resource, XDG_SHELL_ERROR_ROLE,
+				       "This wl_surface is already an "
+				       "xdg_popup");
+		return;
+	}
+
 	if (weston_surface_set_role(surface, "xdg_popup",
 				    resource, XDG_SHELL_ERROR_ROLE) < 0)
 		return;
-- 
2.1.0