wayland: Clean up surface role assignment

Use a better name, use GNOME conventions for error handling, open code the
client error reporting and send the error to the correct resource.
wl_subcompositor doesn't have a role error yet, so continue use some
other error. The only effect of this is error received in the client will
be a bit confusing, it will still be disconnected.

https://bugzilla.gnome.org/show_bug.cgi?id=754215

4 files changed, 58 insertions, 44 deletions

diff --git a/src/wayland/meta-wayland-data-device.c b/src/wayland/meta-wayland-data-device.c
index 099f6c503..3771d1996 100644
--- a/src/wayland/meta-wayland-data-device.c
+++ b/src/wayland/meta-wayland-data-device.c
@@ -537,11 +537,14 @@ data_device_start_drag (struct wl_client *client,
     drag_source = wl_resource_get_user_data (source_resource);
 
   if (icon_resource &&
-      meta_wayland_surface_set_role (icon_surface,
-                                     META_WAYLAND_SURFACE_ROLE_DND,
-                                     resource,
-                                     WL_DATA_DEVICE_ERROR_ROLE) != 0)
-    return;
+      !meta_wayland_surface_assign_role (icon_surface,
+                                         META_WAYLAND_SURFACE_ROLE_DND))
+    {
+      wl_resource_post_error (resource, WL_DATA_DEVICE_ERROR_ROLE,
+                              "wl_surface@%d already has a different role",
+                              wl_resource_get_id (icon_resource));
+      return;
+    }
 
   meta_wayland_pointer_set_focus (&seat->pointer, NULL);
   meta_wayland_data_device_start_drag (data_device, client,
diff --git a/src/wayland/meta-wayland-pointer.c b/src/wayland/meta-wayland-pointer.c
index 385a2985c..f1e4d2f05 100644
--- a/src/wayland/meta-wayland-pointer.c
+++ b/src/wayland/meta-wayland-pointer.c
@@ -776,11 +776,14 @@ pointer_set_cursor (struct wl_client *client,
 
   if (surface)
     {
-      if (meta_wayland_surface_set_role (surface,
-                                         META_WAYLAND_SURFACE_ROLE_CURSOR,
-                                         resource,
-                                         WL_POINTER_ERROR_ROLE) != 0)
-        return;
+      if (!meta_wayland_surface_assign_role (surface,
+                                             META_WAYLAND_SURFACE_ROLE_CURSOR))
+        {
+          wl_resource_post_error (resource, WL_POINTER_ERROR_ROLE,
+                                  "wl_surface@%d already has a different role",
+                                  wl_resource_get_id (surface_resource));
+          return;
+        }
     }
 
   pointer->hotspot_x = x;
diff --git a/src/wayland/meta-wayland-surface.c b/src/wayland/meta-wayland-surface.c
index 2a9df0a50..369d01d84 100644
--- a/src/wayland/meta-wayland-surface.c
+++ b/src/wayland/meta-wayland-surface.c
@@ -72,24 +72,19 @@ GType meta_wayland_surface_get_type (void) G_GNUC_CONST;
 
 G_DEFINE_TYPE (MetaWaylandSurface, meta_wayland_surface, G_TYPE_OBJECT);
 
-int
-meta_wayland_surface_set_role (MetaWaylandSurface    *surface,
-                               MetaWaylandSurfaceRole role,
-                               struct wl_resource    *error_resource,
-                               uint32_t               error_code)
+gboolean
+meta_wayland_surface_assign_role (MetaWaylandSurface    *surface,
+                                  MetaWaylandSurfaceRole role)
 {
   if (surface->role == META_WAYLAND_SURFACE_ROLE_NONE ||
       surface->role == role)
     {
       surface->role = role;
-      return 0;
+      return TRUE;
     }
   else
     {
-      wl_resource_post_error (error_resource, error_code,
-                              "wl_surface@%d already has a different role",
-                              wl_resource_get_id (surface->resource));
-      return -1;
+      return FALSE;
     }
 }
 
@@ -1283,11 +1278,14 @@ xdg_shell_get_xdg_surface (struct wl_client *client,
       return;
     }
 
-  if (meta_wayland_surface_set_role (surface,
-                                     META_WAYLAND_SURFACE_ROLE_XDG_SURFACE,
-                                     surface_resource,
-                                     XDG_SHELL_ERROR_ROLE) != 0)
-    return;
+  if (!meta_wayland_surface_assign_role (surface,
+                                         META_WAYLAND_SURFACE_ROLE_XDG_SURFACE))
+    {
+      wl_resource_post_error (resource, XDG_SHELL_ERROR_ROLE,
+                              "wl_surface@%d already has a different role",
+                              wl_resource_get_id (surface->resource));
+      return;
+    }
 
   surface->xdg_surface = wl_resource_create (client, &xdg_surface_interface, wl_resource_get_version (resource), id);
   wl_resource_set_implementation (surface->xdg_surface, &meta_wayland_xdg_surface_interface, surface, xdg_surface_destructor);
@@ -1391,11 +1389,14 @@ xdg_shell_get_xdg_popup (struct wl_client *client,
       return;
     }
 
-  if (meta_wayland_surface_set_role (surface,
-                                     META_WAYLAND_SURFACE_ROLE_XDG_POPUP,
-                                     surface_resource,
-                                     XDG_SHELL_ERROR_ROLE) != 0)
-    return;
+  if (!meta_wayland_surface_assign_role (surface,
+                                         META_WAYLAND_SURFACE_ROLE_XDG_POPUP))
+    {
+      wl_resource_post_error (resource, XDG_SHELL_ERROR_ROLE,
+                              "wl_surface@%d already has a different role",
+                              wl_resource_get_id (surface->resource));
+      return;
+    }
 
   if (parent_surf == NULL ||
       parent_surf->window == NULL ||
@@ -1731,11 +1732,14 @@ wl_shell_get_shell_surface (struct wl_client *client,
       return;
     }
 
-  if (meta_wayland_surface_set_role (surface,
-                                     META_WAYLAND_SURFACE_ROLE_WL_SHELL_SURFACE,
-                                     surface_resource,
-                                     WL_SHELL_ERROR_ROLE) != 0)
-    return;
+  if (!meta_wayland_surface_assign_role (surface,
+                                         META_WAYLAND_SURFACE_ROLE_WL_SHELL_SURFACE))
+    {
+      wl_resource_post_error (resource, WL_SHELL_ERROR_ROLE,
+                              "wl_surface@%d already has a different role",
+                              wl_resource_get_id (surface->resource));
+      return;
+    }
 
   surface->wl_shell_surface = wl_resource_create (client, &wl_shell_surface_interface, wl_resource_get_version (resource), id);
   wl_resource_set_implementation (surface->wl_shell_surface, &meta_wayland_wl_shell_surface_interface, surface, wl_shell_surface_destructor);
@@ -2080,11 +2084,17 @@ wl_subcompositor_get_subsurface (struct wl_client *client,
       return;
     }
 
-  if (meta_wayland_surface_set_role (surface,
-                                     META_WAYLAND_SURFACE_ROLE_SUBSURFACE,
-                                     surface_resource,
-                                     WL_SHELL_ERROR_ROLE) != 0)
-    return;
+  if (!meta_wayland_surface_assign_role (surface,
+                                         META_WAYLAND_SURFACE_ROLE_SUBSURFACE))
+    {
+      /* FIXME: There is no subcompositor "role" error yet, so lets just use something
+       * similar until there is.
+       */
+      wl_resource_post_error (resource, WL_SHELL_ERROR_ROLE,
+                              "wl_surface@%d already has a different role",
+                              wl_resource_get_id (surface->resource));
+      return;
+    }
 
   surface->wl_subsurface = wl_resource_create (client, &wl_subsurface_interface, wl_resource_get_version (resource), id);
   wl_resource_set_implementation (surface->wl_subsurface, &meta_wayland_wl_subsurface_interface, surface, wl_subsurface_destructor);
diff --git a/src/wayland/meta-wayland-surface.h b/src/wayland/meta-wayland-surface.h
index 25debefe5..7efb65f42 100644
--- a/src/wayland/meta-wayland-surface.h
+++ b/src/wayland/meta-wayland-surface.h
@@ -174,10 +174,8 @@ MetaWaylandSurface *meta_wayland_surface_create (MetaWaylandCompositor *composit
                                                  struct wl_resource    *compositor_resource,
                                                  guint32                id);
 
-int                meta_wayland_surface_set_role (MetaWaylandSurface    *surface,
-                                                  MetaWaylandSurfaceRole role,
-                                                  struct wl_resource    *error_resource,
-                                                  uint32_t               error_code);
+gboolean            meta_wayland_surface_assign_role (MetaWaylandSurface    *surface,
+                                                      MetaWaylandSurfaceRole role);
 
 void                meta_wayland_surface_set_window (MetaWaylandSurface *surface,
                                                      MetaWindow         *window);