WindowServer/LibGUI: Add window focus events

userspace/libraries/LibGUI/Window.cpp

@@ -335,6 +335,10 @@ namespace LibGUI
 					if (m_window_shown_event_callback)
 						m_window_shown_event_callback(TRY_OR_BREAK(EventPacket::WindowShownEvent::deserialize(packet_data.span())).event);
 					break;
+				case PacketType::WindowFocusEvent:
+					if (m_window_focus_event_callback)
+						m_window_focus_event_callback(TRY_OR_BREAK(EventPacket::WindowFocusEvent::deserialize(packet_data.span())).event);
+					break;
 				case PacketType::KeyEvent:
 					if (m_key_event_callback)
 						m_key_event_callback(TRY_OR_BREAK(EventPacket::KeyEvent::deserialize(packet_data.span())).event);

userspace/libraries/LibGUI/include/LibGUI/Packet.h

@@ -217,6 +217,7 @@ namespace LibGUI
 		CloseWindowEvent,
 		ResizeWindowEvent,
 		WindowShownEvent,
+		WindowFocusEvent,
 		KeyEvent,
 		MouseButtonEvent,
 		MouseMoveEvent,
@@ -333,6 +334,14 @@ namespace LibGUI
 			event_t, event
 		);
 
+		DEFINE_PACKET_EXTRA(
+			WindowFocusEvent,
+			struct event_t {
+				bool focused;
+			},
+			event_t, event
+		);
+
 		DEFINE_PACKET_EXTRA(
 			KeyEvent,
 			using event_t = LibInput::KeyEvent,

userspace/libraries/LibGUI/include/LibGUI/Window.h

@@ -76,6 +76,7 @@ namespace LibGUI
 		void set_mouse_move_event_callback(BAN::Function<void(EventPacket::MouseMoveEvent::event_t)> callback)     { m_mouse_move_event_callback = callback; }
 		void set_mouse_scroll_event_callback(BAN::Function<void(EventPacket::MouseScrollEvent::event_t)> callback) { m_mouse_scroll_event_callback = callback; }
 		void set_window_shown_event_callback(BAN::Function<void(EventPacket::WindowShownEvent::event_t)> callback) { m_window_shown_event_callback = callback; }
+		void set_window_focus_event_callback(BAN::Function<void(EventPacket::WindowFocusEvent::event_t)> callback) { m_window_focus_event_callback = callback; }
 
 		int server_fd() const { return m_server_fd; }
 
@@ -108,6 +109,7 @@ namespace LibGUI
 		BAN::Function<void()>                                       m_close_window_event_callback;
 		BAN::Function<void()>                                       m_resize_window_event_callback;
 		BAN::Function<void(EventPacket::WindowShownEvent::event_t)> m_window_shown_event_callback;
+		BAN::Function<void(EventPacket::WindowFocusEvent::event_t)> m_window_focus_event_callback;
 		BAN::Function<void(EventPacket::KeyEvent::event_t)>         m_key_event_callback;
 		BAN::Function<void(EventPacket::MouseButtonEvent::event_t)> m_mouse_button_event_callback;
 		BAN::Function<void(EventPacket::MouseMoveEvent::event_t)>   m_mouse_move_event_callback;

userspace/programs/WindowServer/WindowServer.cpp

@@ -90,7 +90,7 @@ void WindowServer::on_window_create(int fd, const LibGUI::WindowPacket::WindowCr
 
 	window_popper.disable();
 
-	if (packet.attributes.focusable)
+	if (packet.attributes.shown && packet.attributes.focusable)
 		set_focused_window(window);
 	else if (m_client_windows.size() > 1)
 		BAN::swap(m_client_windows[m_client_windows.size() - 1], m_client_windows[m_client_windows.size() - 2]);
@@ -197,6 +197,9 @@ void WindowServer::on_window_set_attributes(int fd, const LibGUI::WindowPacket::
 	};
 	if (auto ret = event_packet.send_serialized(target_window->client_fd()); ret.is_error())
 		dwarnln("could not send window shown event: {}", ret.error());
+
+	if (packet.attributes.focusable && packet.attributes.shown)
+		set_focused_window(target_window);
 }
 
 void WindowServer::on_window_set_mouse_relative(int fd, const LibGUI::WindowPacket::WindowSetMouseRelative& packet)
@@ -781,6 +784,17 @@ void WindowServer::set_focused_window(BAN::RefPtr<Window> window)
 		invalidate(cursor_area());
 	}
 
+	if (m_focused_window)
+	{
+		LibGUI::EventPacket::WindowFocusEvent packet;
+		packet.event.focused = false;
+		if (auto ret = packet.send_serialized(m_focused_window->client_fd()); ret.is_error())
+		{
+			dwarnln("could not send window focus event: {}", ret.error());
+			return;
+		}
+	}
+
 	for (size_t i = m_client_windows.size(); i > 0; i--)
 	{
 		if (m_client_windows[i - 1] == window)
@@ -792,6 +806,17 @@ void WindowServer::set_focused_window(BAN::RefPtr<Window> window)
 			break;
 		}
 	}
+
+	if (m_focused_window)
+	{
+		LibGUI::EventPacket::WindowFocusEvent packet;
+		packet.event.focused = true;
+		if (auto ret = packet.send_serialized(m_focused_window->client_fd()); ret.is_error())
+		{
+			dwarnln("could not send window focus event: {}", ret.error());
+			return;
+		}
+	}
 }
 
 static uint32_t alpha_blend(uint32_t color_a, uint32_t color_b)