win: cache the EWMH fullscreen property

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

src/event.c

@@ -565,6 +565,13 @@ static inline void ev_property_notify(session_t *ps, xcb_property_notify_event_t
 		}
 	}
 
+	if (!ps->o.no_ewmh_fullscreen && ev->atom == ps->atoms->a_NET_WM_STATE) {
+		auto w = find_toplevel(ps, ev->window);
+		if (w) {
+			win_set_property_stale(w, ev->atom);
+		}
+	}
+
 	// Check for other atoms we are tracking
 	for (latom_t *platom = ps->track_atom_lst; platom; platom = platom->next) {
 		if (platom->atom == ev->atom) {

src/win.c

@@ -73,6 +73,11 @@ static void
 win_update_frame_extents(session_t *ps, struct managed_win *w, xcb_window_t client);
 static void win_update_prop_shadow_raw(session_t *ps, struct managed_win *w);
 static void win_update_prop_shadow(session_t *ps, struct managed_win *w);
+/**
+ * Update window EWMH fullscreen state.
+ */
+bool win_update_prop_fullscreen(struct x_connection *c, const struct atom *atoms,
+                                struct managed_win *w);
 /**
  * Update leader of a window.
  */
@@ -457,6 +462,12 @@ static void win_update_properties(session_t *ps, struct managed_win *w) {
 		win_update_prop_shadow(ps, w);
 	}
 
+	if (win_fetch_and_unset_property_stale(w, ps->atoms->a_NET_WM_STATE)) {
+		if (win_update_prop_fullscreen(&ps->c, ps->atoms, w)) {
+			win_set_flags(w, WIN_FLAGS_FACTOR_CHANGED);
+		}
+	}
+
 	if (win_fetch_and_unset_property_stale(w, ps->atoms->aWM_CLIENT_LEADER) ||
 	    win_fetch_and_unset_property_stale(w, ps->atoms->aWM_TRANSIENT_FOR)) {
 		win_update_leader(ps, w);
@@ -1012,6 +1023,30 @@ void win_update_prop_shadow(session_t *ps, struct managed_win *w) {
 	}
 }
 
+/**
+ * Update window EWMH fullscreen state.
+ */
+bool win_update_prop_fullscreen(struct x_connection *c, const struct atom *atoms,
+                                struct managed_win *w) {
+	auto prop = x_get_prop(c, w->client_win, atoms->a_NET_WM_STATE, 12, XCB_ATOM_ATOM, 0);
+	if (!prop.nitems) {
+		return false;
+	}
+
+	bool is_fullscreen = false;
+	for (uint32_t i = 0; i < prop.nitems; i++) {
+		if (prop.atom[i] == atoms->a_NET_WM_STATE_FULLSCREEN) {
+			is_fullscreen = true;
+			break;
+		}
+	}
+	free_winprop(&prop);
+
+	bool changed = w->is_ewmh_fullscreen != is_fullscreen;
+	w->is_ewmh_fullscreen = is_fullscreen;
+	return changed;
+}
+
 static void win_determine_clip_shadow_above(session_t *ps, struct managed_win *w) {
 	bool should_crop = (ps->o.wintype_option[w->window_type].clip_shadow_above ||
 	                    c2_match(ps, w, ps->o.shadow_clip_list, NULL));
@@ -1723,6 +1758,7 @@ struct win *fill_win(session_t *ps, struct win *w) {
 	    ps->atoms->a_NET_WM_NAME,        ps->atoms->aWM_CLASS,
 	    ps->atoms->aWM_WINDOW_ROLE,      ps->atoms->a_COMPTON_SHADOW,
 	    ps->atoms->aWM_CLIENT_LEADER,    ps->atoms->aWM_TRANSIENT_FOR,
+	    ps->atoms->a_NET_WM_STATE,
 	};
 	win_set_properties_stale(new, init_stale_props, ARR_SIZE(init_stale_props));
 
@@ -2717,34 +2753,6 @@ static inline bool rect_is_fullscreen(const session_t *ps, int x, int y, int wid
 	return (x <= 0 && y <= 0 && (x + wid) >= ps->root_width && (y + hei) >= ps->root_height);
 }
 
-/**
- * Check if a window is full-screen using EWMH
- *
- * TODO(yshui) cache this property
- */
-static inline bool
-win_is_fullscreen_xcb(xcb_connection_t *c, const struct atom *a, const xcb_window_t w) {
-	xcb_get_property_cookie_t prop =
-	    xcb_get_property(c, 0, w, a->a_NET_WM_STATE, XCB_ATOM_ATOM, 0, 12);
-	xcb_get_property_reply_t *reply = xcb_get_property_reply(c, prop, NULL);
-	if (!reply) {
-		return false;
-	}
-
-	if (reply->length) {
-		xcb_atom_t *val = xcb_get_property_value(reply);
-		for (uint32_t i = 0; i < reply->length; i++) {
-			if (val[i] != a->a_NET_WM_STATE_FULLSCREEN) {
-				continue;
-			}
-			free(reply);
-			return true;
-		}
-	}
-	free(reply);
-	return false;
-}
-
 /// Set flags on a window. Some sanity checks are performed
 void win_set_flags(struct managed_win *w, uint64_t flags) {
 	log_debug("Set flags %" PRIu64 " to window %#010x (%s)", flags, w->base.id, w->name);
@@ -2830,8 +2838,7 @@ bool win_check_flags_all(struct managed_win *w, uint64_t flags) {
  * It's not using w->border_size for performance measures.
  */
 bool win_is_fullscreen(const session_t *ps, const struct managed_win *w) {
-	if (!ps->o.no_ewmh_fullscreen &&
-	    win_is_fullscreen_xcb(ps->c.c, ps->atoms, w->client_win)) {
+	if (!ps->o.no_ewmh_fullscreen && w->is_ewmh_fullscreen) {
 		return true;
 	}
 	return rect_is_fullscreen(ps, w->g.x, w->g.y, w->widthb, w->heightb) &&

src/win.h

@@ -199,6 +199,8 @@ struct managed_win {
 	char *class_general;
 	/// <code>WM_WINDOW_ROLE</code> value of the window.
 	char *role;
+	/// Whether the window sets the EWMH fullscreen property.
+	bool is_ewmh_fullscreen;
 
 	// Opacity-related members
 	/// Current window opacity.