view: add view_wants_focus enum (NEVER/ALWAYS/OFFER) and function

This allows identifying XWayland views using the ICCCM "Globally Active"
input model. Later commits will improve handling of these views.

No functional change in this commit.

include/view.h

@@ -36,6 +36,21 @@ enum view_edge {
 	VIEW_EDGE_CENTER,
 };
 
+enum view_wants_focus {
+	/* View does not want focus */
+	VIEW_WANTS_FOCUS_NEVER = 0,
+	/* View wants focus */
+	VIEW_WANTS_FOCUS_ALWAYS,
+	/*
+	 * View should be offered focus and may accept or decline
+	 * (a.k.a. ICCCM Globally Active input model). Labwc generally
+	 * avoids focusing these views automatically (e.g. when another
+	 * view on top is closed) but they may be focused by user action
+	 * (e.g. mouse click).
+	 */
+	VIEW_WANTS_FOCUS_OFFER,
+};
+
 struct view;
 struct wlr_surface;
 
@@ -72,8 +87,8 @@ struct view_impl {
 	/* determines if view and surface are owned by the same process */
 	bool (*is_related)(struct view *self, struct wlr_surface *surface);
 	struct view_size_hints (*get_size_hints)(struct view *self);
-	/* if not implemented, view is assumed to want focus */
-	bool (*wants_focus)(struct view *self);
+	/* if not implemented, VIEW_WANTS_FOCUS_ALWAYS is assumed */
+	enum view_wants_focus (*wants_focus)(struct view *self);
 };
 
 struct view {
@@ -273,6 +288,8 @@ struct view *view_next(struct wl_list *head, struct view *view,
 void view_array_append(struct server *server, struct wl_array *views,
 	enum lab_view_criteria criteria);
 
+enum view_wants_focus view_wants_focus(struct view *view);
+
 /**
  * view_is_focusable() - Check whether or not a view can be focused
  * @view: view to be checked

src/view.c

@@ -143,6 +143,16 @@ view_array_append(struct server *server, struct wl_array *views,
 	}
 }
 
+enum view_wants_focus
+view_wants_focus(struct view *view)
+{
+	assert(view);
+	if (view->impl->wants_focus) {
+		return view->impl->wants_focus(view);
+	}
+	return VIEW_WANTS_FOCUS_ALWAYS;
+}
+
 bool
 view_is_focusable(struct view *view)
 {
@@ -150,7 +160,7 @@ view_is_focusable(struct view *view)
 	if (!view->surface) {
 		return false;
 	}
-	if (view->impl->wants_focus && !view->impl->wants_focus(view)) {
+	if (view_wants_focus(view) != VIEW_WANTS_FOCUS_ALWAYS) {
 		return false;
 	}
 	return (view->mapped || view->minimized);

src/xwayland.c

@@ -30,29 +30,61 @@ xwayland_view_get_size_hints(struct view *view)
 	};
 }
 
-static bool
+static enum view_wants_focus
 xwayland_view_wants_focus(struct view *view)
 {
-	xcb_icccm_wm_hints_t *hints = xwayland_surface_from_view(view)->hints;
-	if (!hints) {
-		return true;
-	}
+	struct wlr_xwayland_surface *xsurface =
+		xwayland_surface_from_view(view);
+
+	switch (wlr_xwayland_icccm_input_model(xsurface)) {
 	/*
-	 * Paraphrased from ICCCM section 4.1.7 (Input Focus):
+	 * Abbreviated from ICCCM section 4.1.7 (Input Focus):
 	 *
-	 * Clients set the input field of WM_HINTS to True to indicate
-	 * that they require window manager assistance in acquiring the
-	 * input focus. Clients set the input field to False to request
-	 * that the window manager not set the input focus to their
-	 * top-level window.
+	 * Passive Input - The client expects keyboard input but never
+	 * explicitly sets the input focus.
+	 * Locally Active Input - The client expects keyboard input and
+	 * explicitly sets the input focus, but it only does so when one
+	 * of its windows already has the focus.
 	 *
-	 * Clients that use XSetInputFocus() to explicitly set the input
-	 * focus should set the WM_TAKE_FOCUS atom in WM_PROTOCOLS.
-	 * Currently, labwc does not support this method of taking focus
-	 * and thus ignores WM_TAKE_FOCUS. These views can still be
-	 * focused by explicit user action (e.g. clicking in them).
+	 * Passive and Locally Active clients set the input field of
+	 * WM_HINTS to True, which indicates that they require window
+	 * manager assistance in acquiring the input focus.
 	 */
-	return (bool)hints->input;
+	case WLR_ICCCM_INPUT_MODEL_PASSIVE:
+	case WLR_ICCCM_INPUT_MODEL_LOCAL:
+		return VIEW_WANTS_FOCUS_ALWAYS;
+
+	/*
+	 * Globally Active Input - The client expects keyboard input and
+	 * explicitly sets the input focus, even when it is in windows
+	 * the client does not own. ... It wants to prevent the window
+	 * manager from setting the input focus to any of its windows
+	 * [because it may or may not want focus].
+	 *
+	 * Globally Active client windows may receive a WM_TAKE_FOCUS
+	 * message from the window manager. If they want the focus, they
+	 * should respond with a SetInputFocus request.
+	 *
+	 * [Currently, labwc does not fully support clients voluntarily
+	 * taking focus via the WM_TAKE_FOCUS + SetInputFocus mechanism
+	 * and avoids automatically focusing Globally Active windows.
+	 * This may change in future.]
+	 */
+	case WLR_ICCCM_INPUT_MODEL_GLOBAL:
+		return VIEW_WANTS_FOCUS_OFFER;
+
+	/*
+	 * No Input - The client never expects keyboard input.
+	 *
+	 * No Input and Globally Active clients set the input field to
+	 * False, which requests that the window manager not set the
+	 * input focus to their top-level window.
+	 */
+	case WLR_ICCCM_INPUT_MODEL_NONE:
+		break;
+	}
+
+	return VIEW_WANTS_FOCUS_NEVER;
 }
 
 static struct wlr_xwayland_surface *