Wayland: Unify key handling logic

Previously we had different logic for direct key presses and client-side
key repetition, as one queued up input events and the other dispatched
them directly (client-side key repetition is run from the main thread).

I kinda figured out that this difference doesn't really matter, as we
can queue them up before the thread message dispatching logic. That's
exactly what we do now, which allows us to make a single method for both
of them, making the code much clearer and simplifying future maintenance.

This patch also includes a tiny fixup in the compose logic, which checks
for the validity of the generated key event before actually working with
it. The cases in which we can end up with an invalid reference are very
few, so it's not the end of the world, but it's still absolutely a good
idea to check, to avoid nasty surprises down the line.

platform/linuxbsd/wayland/display_server_wayland.cpp

@@ -1695,6 +1695,8 @@ void DisplayServerWayland::try_suspend() {
 void DisplayServerWayland::process_events() {
 	wayland_thread.mutex.lock();
 
+	wayland_thread.keyboard_echo_keys();
+
 	while (wayland_thread.has_message()) {
 		Ref<WaylandThread::Message> msg = wayland_thread.pop_message();
 
@@ -1837,8 +1839,6 @@ void DisplayServerWayland::process_events() {
 		}
 	}
 
-	wayland_thread.keyboard_echo_keys();
-
 	switch (suspend_state) {
 		case SuspendState::NONE: {
 			bool emulate_vsync = false;

platform/linuxbsd/wayland/wayland_thread.cpp

@@ -302,6 +302,73 @@ Ref<InputEventKey> WaylandThread::_seat_state_get_unstuck_key_event(SeatState *p
 	return event;
 }
 
+void WaylandThread::_seat_state_handle_xkb_keycode(SeatState *p_ss, xkb_keycode_t p_xkb_keycode, bool p_pressed, bool p_echo) {
+	ERR_FAIL_NULL(p_ss);
+
+	WaylandThread *wayland_thread = p_ss->wayland_thread;
+	ERR_FAIL_NULL(wayland_thread);
+
+	Key last_key = Key::NONE;
+	xkb_compose_status compose_status = xkb_compose_state_get_status(p_ss->xkb_compose_state);
+
+	if (p_pressed) {
+		xkb_keysym_t keysym = xkb_state_key_get_one_sym(p_ss->xkb_state, p_xkb_keycode);
+		xkb_compose_feed_result compose_result = xkb_compose_state_feed(p_ss->xkb_compose_state, keysym);
+		compose_status = xkb_compose_state_get_status(p_ss->xkb_compose_state);
+
+		if (compose_result == XKB_COMPOSE_FEED_ACCEPTED && compose_status == XKB_COMPOSE_COMPOSED) {
+			// We need to generate multiple key events to report the composed result, One
+			// per character.
+			char str_xkb[256] = {};
+			int str_xkb_size = xkb_compose_state_get_utf8(p_ss->xkb_compose_state, str_xkb, 255);
+
+			String decoded_str = String::utf8(str_xkb, str_xkb_size);
+			for (int i = 0; i < decoded_str.length(); ++i) {
+				Ref<InputEventKey> k = _seat_state_get_key_event(p_ss, p_xkb_keycode, p_pressed);
+				if (k.is_null()) {
+					continue;
+				}
+
+				k->set_unicode(decoded_str[i]);
+				k->set_echo(p_echo);
+
+				Ref<InputEventMessage> msg;
+				msg.instantiate();
+				msg->event = k;
+				wayland_thread->push_message(msg);
+
+				last_key = k->get_keycode();
+			}
+		}
+	}
+
+	if (last_key == Key::NONE && compose_status == XKB_COMPOSE_NOTHING) {
+		// If we continued with other compose status (e.g. XKB_COMPOSE_COMPOSING) we
+		// would get the composing keys _and_ the result.
+		Ref<InputEventKey> k = _seat_state_get_key_event(p_ss, p_xkb_keycode, p_pressed);
+		if (k.is_valid()) {
+			k->set_echo(p_echo);
+
+			Ref<InputEventMessage> msg;
+			msg.instantiate();
+			msg->event = k;
+			wayland_thread->push_message(msg);
+
+			last_key = k->get_keycode();
+		}
+	}
+
+	if (last_key != Key::NONE) {
+		Ref<InputEventKey> uk = _seat_state_get_unstuck_key_event(p_ss, p_xkb_keycode, p_pressed, last_key);
+		if (uk.is_valid()) {
+			Ref<InputEventMessage> u_msg;
+			u_msg.instantiate();
+			u_msg->event = uk;
+			wayland_thread->push_message(u_msg);
+		}
+	}
+}
+
 void WaylandThread::_set_current_seat(struct wl_seat *p_seat) {
 	if (p_seat == wl_seat_current) {
 		return;
@@ -2198,16 +2265,10 @@ void WaylandThread::_wl_keyboard_on_key(void *data, struct wl_keyboard *wl_keybo
 		return;
 	}
 
-	WaylandThread *wayland_thread = ss->wayland_thread;
-	ERR_FAIL_NULL(wayland_thread);
-
 	// We have to add 8 to the scancode to get an XKB-compatible keycode.
 	xkb_keycode_t xkb_keycode = key + 8;
 
 	bool pressed = state & WL_KEYBOARD_KEY_STATE_PRESSED;
-	Key last_key = Key::NONE;
-
-	xkb_compose_status compose_status = xkb_compose_state_get_status(ss->xkb_compose_state);
 
 	if (pressed) {
 		if (xkb_keymap_key_repeats(ss->xkb_keymap, xkb_keycode)) {
@@ -2216,58 +2277,11 @@ void WaylandThread::_wl_keyboard_on_key(void *data, struct wl_keyboard *wl_keybo
 		}
 
 		ss->last_key_pressed_serial = serial;
-
-		xkb_keysym_t keysym = xkb_state_key_get_one_sym(ss->xkb_state, xkb_keycode);
-		xkb_compose_feed_result compose_result = xkb_compose_state_feed(ss->xkb_compose_state, keysym);
-		compose_status = xkb_compose_state_get_status(ss->xkb_compose_state);
-
-		if (compose_result == XKB_COMPOSE_FEED_ACCEPTED && compose_status == XKB_COMPOSE_COMPOSED) {
-			// We need to generate multiple key events to report the composed result, One
-			// per character.
-			char str_xkb[256] = {};
-			int str_xkb_size = xkb_compose_state_get_utf8(ss->xkb_compose_state, str_xkb, 255);
-
-			String decoded_str = String::utf8(str_xkb, str_xkb_size);
-			for (int i = 0; i < decoded_str.length(); ++i) {
-				Ref<InputEventKey> k = _seat_state_get_key_event(ss, xkb_keycode, pressed);
-				k->set_unicode(decoded_str[i]);
-
-				Ref<InputEventMessage> msg;
-				msg.instantiate();
-				msg->event = k;
-				wayland_thread->push_message(msg);
-
-				last_key = k->get_keycode();
-			}
-		}
 	} else if (ss->repeating_keycode == xkb_keycode) {
 		ss->repeating_keycode = XKB_KEYCODE_INVALID;
 	}
 
-	if (last_key == Key::NONE && compose_status == XKB_COMPOSE_NOTHING) {
-		// If we continued with other compose status (e.g. XKB_COMPOSE_COMPOSING) we
-		// would get the composing keys _and_ the result.
-		Ref<InputEventKey> k = _seat_state_get_key_event(ss, xkb_keycode, pressed);
-
-		if (k.is_valid()) {
-			Ref<InputEventMessage> msg;
-			msg.instantiate();
-			msg->event = k;
-			wayland_thread->push_message(msg);
-
-			last_key = k->get_keycode();
-		}
-	}
-
-	if (last_key != Key::NONE) {
-		Ref<InputEventKey> uk = _seat_state_get_unstuck_key_event(ss, xkb_keycode, pressed, last_key);
-		if (uk.is_valid()) {
-			Ref<InputEventMessage> u_msg;
-			u_msg.instantiate();
-			u_msg->event = uk;
-			wayland_thread->push_message(u_msg);
-		}
-	}
+	_seat_state_handle_xkb_keycode(ss, xkb_keycode, pressed);
 }
 
 void WaylandThread::_wl_keyboard_on_modifiers(void *data, struct wl_keyboard *wl_keyboard, uint32_t serial, uint32_t mods_depressed, uint32_t mods_latched, uint32_t mods_locked, uint32_t group) {
@@ -3683,42 +3697,8 @@ void WaylandThread::seat_state_echo_keys(SeatState *p_ss) {
 
 			int keys_amount = (ticks_delta / p_ss->repeat_key_delay_msec);
 
-			xkb_compose_status compose_status = xkb_compose_state_get_status(p_ss->xkb_compose_state);
-
-			Key last_key = Key::NONE;
 			for (int i = 0; i < keys_amount; i++) {
-				xkb_keysym_t keysym = xkb_state_key_get_one_sym(p_ss->xkb_state, p_ss->repeating_keycode);
-				xkb_compose_feed_result compose_result = xkb_compose_state_feed(p_ss->xkb_compose_state, keysym);
-				compose_status = xkb_compose_state_get_status(p_ss->xkb_compose_state);
-
-				if (compose_result == XKB_COMPOSE_FEED_ACCEPTED && compose_status == XKB_COMPOSE_COMPOSED) {
-					// We need to generate multiple key events to report the composed result, One
-					// per character.
-					char str_xkb[256] = {};
-					int str_xkb_size = xkb_compose_state_get_utf8(p_ss->xkb_compose_state, str_xkb, 255);
-
-					String decoded_str = String::utf8(str_xkb, str_xkb_size);
-					for (int j = 0; j < decoded_str.length(); ++j) {
-						Ref<InputEventKey> k = _seat_state_get_key_event(p_ss, p_ss->repeating_keycode, true);
-						k->set_unicode(decoded_str[j]);
-						Input::get_singleton()->parse_input_event(k);
-
-						last_key = k->get_keycode();
-					}
-				} else if (compose_status == XKB_COMPOSE_NOTHING) {
-					Ref<InputEventKey> k = _seat_state_get_key_event(p_ss, p_ss->repeating_keycode, true);
-					k->set_echo(true);
-					Input::get_singleton()->parse_input_event(k);
-
-					last_key = k->get_keycode();
-				}
-
-				if (last_key != Key::NONE) {
-					Ref<InputEventKey> uk = _seat_state_get_unstuck_key_event(p_ss, p_ss->repeating_keycode, true, last_key);
-					if (uk.is_valid()) {
-						Input::get_singleton()->parse_input_event(uk);
-					}
-				}
+				_seat_state_handle_xkb_keycode(p_ss, p_ss->repeating_keycode, true, true);
 			}
 
 			p_ss->last_repeat_msec += ticks_delta - (ticks_delta % p_ss->repeat_key_delay_msec);

platform/linuxbsd/wayland/wayland_thread.h

@@ -1037,6 +1037,8 @@ private:
 	static Ref<InputEventKey> _seat_state_get_key_event(SeatState *p_ss, xkb_keycode_t p_keycode, bool p_pressed);
 	static Ref<InputEventKey> _seat_state_get_unstuck_key_event(SeatState *p_ss, xkb_keycode_t p_keycode, bool p_pressed, Key p_key);
 
+	static void _seat_state_handle_xkb_keycode(SeatState *p_ss, xkb_keycode_t p_xkb_keycode, bool p_pressed, bool p_echo = false);
+
 	static void _wayland_state_update_cursor();
 
 	void _set_current_seat(struct wl_seat *p_seat);