wayland/xdg-shell: Implement support for xdg_toplevel.wm_capabilities (#780)

Nothing dynamic yet, we don't have API for this, but we need it to
implement the next version. Sending "all" should be equivalent to v4
anyhow, so this is harmless.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3019>

Co-authored-by: Jonas Ådahl <[email protected]>

Author: City-busz

src/wayland/meta-wayland-versions.h

@@ -37,7 +37,7 @@
 /* Global/master objects (version exported by wl_registry and negotiated through bind) */
 #define META_WL_COMPOSITOR_VERSION          5
 #define META_WL_DATA_DEVICE_MANAGER_VERSION 3
-#define META_XDG_WM_BASE_VERSION            4
+#define META_XDG_WM_BASE_VERSION            5
 #define META_WL_SEAT_VERSION                5
 #define META_WL_OUTPUT_VERSION              4
 #define META_XSERVER_VERSION                1

src/wayland/meta-wayland-xdg-shell.c

@@ -693,11 +693,20 @@ fill_states (MetaWaylandXdgToplevel *xdg_toplevel,
     }
 }
 
+static void
+add_wm_capability_value (struct wl_array                   *states,
+                         enum xdg_toplevel_wm_capabilities  wm_capability)
+{
+  *((uint32_t *) wl_array_add (states, sizeof (uint32_t))) = wm_capability;
+}
+
 static void
 meta_wayland_xdg_toplevel_send_configure (MetaWaylandXdgToplevel         *xdg_toplevel,
                                           MetaWaylandWindowConfiguration *configuration)
 {
   MetaWaylandXdgSurface *xdg_surface = META_WAYLAND_XDG_SURFACE (xdg_toplevel);
+  MetaWaylandXdgSurfacePrivate *xdg_surface_priv =
+    meta_wayland_xdg_surface_get_instance_private (xdg_surface);
   struct wl_array states;
 
   wl_array_init (&states);
@@ -715,6 +724,25 @@ meta_wayland_xdg_toplevel_send_configure (MetaWaylandXdgToplevel         *xdg_to
                                            configuration->scale));
     }
 
+  if (!xdg_surface_priv->configure_sent &&
+      wl_resource_get_version (xdg_toplevel->resource) >=
+      XDG_TOPLEVEL_WM_CAPABILITIES_SINCE_VERSION)
+    {
+      struct wl_array wm_capabilities;
+
+      wl_array_init (&wm_capabilities);
+      add_wm_capability_value (&wm_capabilities,
+                               XDG_TOPLEVEL_WM_CAPABILITIES_WINDOW_MENU);
+      add_wm_capability_value (&wm_capabilities,
+                               XDG_TOPLEVEL_WM_CAPABILITIES_MAXIMIZE);
+      add_wm_capability_value (&wm_capabilities,
+                               XDG_TOPLEVEL_WM_CAPABILITIES_FULLSCREEN);
+      add_wm_capability_value (&wm_capabilities,
+                               XDG_TOPLEVEL_WM_CAPABILITIES_MINIMIZE);
+      xdg_toplevel_send_wm_capabilities (xdg_toplevel->resource, &wm_capabilities);
+      wl_array_release (&wm_capabilities);
+    }
+
   xdg_toplevel_send_configure (xdg_toplevel->resource,
                                configuration->width / configuration->scale,
                                configuration->height / configuration->scale,