implement input method keyboard grab

dwl.c

@@ -225,6 +225,8 @@ struct dwl_input_method_relay {
 	struct wl_listener input_method_commit;
 	struct wl_listener input_method_destroy;
 	struct wl_listener input_method_new_popup_surface;
+	struct wl_listener input_method_grab_keyboard;
+	struct wl_listener input_method_keyboard_grab_destroy;
 };
 
 struct dwl_text_input {
@@ -372,6 +374,9 @@ void dwl_input_method_relay_set_focus(struct dwl_input_method_relay *relay,
 struct dwl_text_input *dwl_text_input_create(
 	struct dwl_input_method_relay *relay,
 	struct wlr_text_input_v3 *text_input);
+static void handle_im_grab_keyboard(struct wl_listener *listener, void *data);
+static void handle_im_keyboard_grab_destroy(struct wl_listener *listener,
+		void *data);
 static void zoom(const Arg *arg);
 
 /* variables */
@@ -1307,6 +1312,26 @@ keybinding(uint32_t mods, xkb_keysym_t sym)
 	return handled;
 }
 
+/**
+ * Get keyboard grab of the seat from sway_keyboard if we should forward events
+ * to it.
+ *
+ * Returns NULL if the keyboard is not grabbed by an input method,
+ * or if event is from virtual keyboard of the same client as grab.
+ * TODO: see https://github.com/swaywm/wlroots/issues/2322
+ */
+static struct wlr_input_method_keyboard_grab_v2 *keyboard_get_im_grab(Keyboard* kb) {
+	struct wlr_input_method_v2 *input_method = input_relay->input_method;
+	struct wlr_virtual_keyboard_v1 *virtual_keyboard =
+		wlr_input_device_get_virtual_keyboard(kb->device);
+	if (!input_method || !input_method->keyboard_grab || (virtual_keyboard &&
+				wl_resource_get_client(virtual_keyboard->resource) ==
+				wl_resource_get_client(input_method->keyboard_grab->resource))) {
+		return NULL;
+	}
+	return input_method->keyboard_grab;
+}
+
 void
 keypress(struct wl_listener *listener, void *data)
 {
@@ -1333,6 +1358,16 @@ keypress(struct wl_listener *listener, void *data)
 			handled = keybinding(mods, syms[i]) || handled;
 
 	if (!handled) {
+		/* if there is a keyboard grab, we send the key there */
+		struct wlr_input_method_keyboard_grab_v2 *kb_grab = keyboard_get_im_grab(kb);
+		if (kb_grab) {
+			wlr_input_method_keyboard_grab_v2_set_keyboard(kb_grab,
+				kb->device->keyboard);
+			wlr_input_method_keyboard_grab_v2_send_key(kb_grab,
+				event->time_msec, event->keycode, event->state);
+			return;
+		}
+
 		/* Pass unhandled keycodes along to the client. */
 		wlr_seat_set_keyboard(seat, kb->device);
 		wlr_seat_keyboard_notify_key(seat, event->time_msec,
@@ -1346,6 +1381,13 @@ keypressmod(struct wl_listener *listener, void *data)
 	/* This event is raised when a modifier key, such as shift or alt, is
 	 * pressed. We simply communicate this to the client. */
 	Keyboard *kb = wl_container_of(listener, kb, modifiers);
+	struct wlr_input_method_keyboard_grab_v2 *kb_grab = keyboard_get_im_grab(kb);
+	if (kb_grab) {
+		wlr_input_method_keyboard_grab_v2_send_modifiers(kb_grab,
+				&kb->device->keyboard->modifiers);
+		return;
+	}
+
 	/*
 	 * A seat can only have one keyboard, but this is a limitation of the
 	 * Wayland protocol - not wlroots. We assign all connected keyboards to the
@@ -1403,6 +1445,38 @@ mapnotify(struct wl_listener *listener, void *data)
 	applyrules(c);
 }
 
+static void handle_im_grab_keyboard(struct wl_listener *listener, void *data) {
+	struct dwl_input_method_relay *relay = wl_container_of(listener, relay,
+		input_method_grab_keyboard);
+	struct wlr_input_method_keyboard_grab_v2 *keyboard_grab = data;
+
+	// send modifier state to grab
+	struct wlr_keyboard *active_keyboard = wlr_seat_get_keyboard(seat);
+	wlr_input_method_keyboard_grab_v2_set_keyboard(keyboard_grab,
+		active_keyboard);
+	wlr_input_method_keyboard_grab_v2_send_modifiers(keyboard_grab,
+		&active_keyboard->modifiers);
+
+	wl_signal_add(&keyboard_grab->events.destroy,
+		&relay->input_method_keyboard_grab_destroy);
+	relay->input_method_keyboard_grab_destroy.notify =
+		handle_im_keyboard_grab_destroy;
+}
+
+static void handle_im_keyboard_grab_destroy(struct wl_listener *listener, void *data) {
+	struct dwl_input_method_relay *relay = wl_container_of(listener, relay,
+		input_method_keyboard_grab_destroy);
+	struct wlr_input_method_keyboard_grab_v2 *keyboard_grab = data;
+	wl_list_remove(&relay->input_method_keyboard_grab_destroy.link);
+
+	if (keyboard_grab->keyboard) {
+		// send modifier state to original client
+		wlr_seat_keyboard_notify_modifiers(keyboard_grab->input_method->seat,
+			&keyboard_grab->keyboard->modifiers);
+	}
+}
+
+
 void
 monocle(Monitor *m)
 {
@@ -2593,6 +2667,9 @@ static void relay_handle_input_method(struct wl_listener *listener,
 	wl_signal_add(&relay->input_method->events.new_popup_surface,
 		&relay->input_method_new_popup_surface);
 	relay->input_method_new_popup_surface.notify = handle_im_new_popup_surface;
+	wl_signal_add(&relay->input_method->events.grab_keyboard,
+		&relay->input_method_grab_keyboard);
+	relay->input_method_grab_keyboard.notify = handle_im_grab_keyboard;
 	wl_signal_add(&relay->input_method->events.destroy,
 		&relay->input_method_destroy);
 	relay->input_method_destroy.notify = handle_im_destroy;