LibGUI: Implement enter/leave events (with WindowServer support.)

Windows now learn when the mouse cursor leaves or enters them.
Use this to implement GWidget::{enter,leave}_event() and use that
to implement the CoolBar button effect. :^)

5 files changed, 37 insertions, 5 deletions

diff --git a/WindowServer/WSAPITypes.h b/WindowServer/WSAPITypes.h
index 3ed1b55077..8be470a257 100644
--- a/WindowServer/WSAPITypes.h
+++ b/WindowServer/WSAPITypes.h
@@ -62,6 +62,8 @@ struct WSAPI_ServerMessage {
         MouseMove,
         MouseDown,
         MouseUp,
+        WindowEntered,
+        WindowLeft,
         KeyDown,
         KeyUp,
         WindowActivated,
diff --git a/WindowServer/WSMessage.h b/WindowServer/WSMessage.h
index 0656bc4bd5..3e4f236c70 100644
--- a/WindowServer/WSMessage.h
+++ b/WindowServer/WSMessage.h
@@ -14,6 +14,8 @@ public:
         MouseMove,
         MouseDown,
         MouseUp,
+        WindowEntered,
+        WindowLeft,
         KeyDown,
         KeyUp,
         WindowActivated,
diff --git a/WindowServer/WSWindow.cpp b/WindowServer/WSWindow.cpp
index 61e9073123..5c74b0899a 100644
--- a/WindowServer/WSWindow.cpp
+++ b/WindowServer/WSWindow.cpp
@@ -94,6 +94,12 @@ void WSWindow::on_message(WSMessage& message)
         server_message.mouse.button = to_api(static_cast<WSMouseEvent&>(message).button());
         server_message.mouse.buttons = static_cast<WSMouseEvent&>(message).buttons();
         break;
+    case WSMessage::WindowEntered:
+        server_message.type = WSAPI_ServerMessage::Type::WindowEntered;
+        break;
+    case WSMessage::WindowLeft:
+        server_message.type = WSAPI_ServerMessage::Type::WindowLeft;
+        break;
     case WSMessage::KeyDown:
         server_message.type = WSAPI_ServerMessage::Type::KeyDown;
         server_message.key.character = static_cast<WSKeyEvent&>(message).character();
diff --git a/WindowServer/WSWindowManager.cpp b/WindowServer/WSWindowManager.cpp
index eafa5f38e7..65db97df6d 100644
--- a/WindowServer/WSWindowManager.cpp
+++ b/WindowServer/WSWindowManager.cpp
@@ -488,8 +488,10 @@ void WSWindowManager::handle_close_button_mouse_event(WSWindow& window, WSMouseE
     }
 }
 
-void WSWindowManager::process_mouse_event(WSMouseEvent& event)
+void WSWindowManager::process_mouse_event(WSMouseEvent& event, WSWindow*& event_window)
 {
+    event_window = nullptr;
+
     if (event.type() == WSMessage::MouseUp && event.button() == MouseButton::Left) {
         if (m_drag_window) {
 #ifdef DRAG_DEBUG
@@ -561,6 +563,7 @@ void WSWindowManager::process_mouse_event(WSMouseEvent& event)
                 move_to_front(window);
                 set_active_window(&window);
             }
+            event_window = &window;
             // FIXME: Should we just alter the coordinates of the existing MouseEvent and pass it through?
             Point position { event.x() - window.rect().x(), event.y() - window.rect().y() };
             auto local_event = make<WSMouseEvent>(event.type(), position, event.buttons(), event.button());
@@ -753,8 +756,12 @@ void WSWindowManager::draw_cursor()
 
 void WSWindowManager::on_message(WSMessage& message)
 {
-    if (message.is_mouse_event())
-        return process_mouse_event(static_cast<WSMouseEvent&>(message));
+    if (message.is_mouse_event()) {
+        WSWindow* event_window = nullptr;
+        process_mouse_event(static_cast<WSMouseEvent&>(message), event_window);
+        set_hovered_window(event_window);
+        return;
+    }
 
     if (message.is_key_event()) {
         // FIXME: This is a good place to hook key events globally. :)
@@ -795,6 +802,20 @@ void WSWindowManager::set_active_window(WSWindow* window)
     }
 }
 
+void WSWindowManager::set_hovered_window(WSWindow* window)
+{
+    if (m_hovered_window.ptr() == window)
+        return;
+
+    if (m_hovered_window)
+        WSMessageLoop::the().post_message(m_hovered_window.ptr(), make<WSMessage>(WSMessage::WindowLeft));
+
+    m_hovered_window = window ? window->make_weak_ptr() : nullptr;
+
+    if (m_hovered_window)
+        WSMessageLoop::the().post_message(m_hovered_window.ptr(), make<WSMessage>(WSMessage::WindowEntered));
+}
+
 void WSWindowManager::invalidate()
 {
     m_dirty_rects.clear_with_capacity();
diff --git a/WindowServer/WSWindowManager.h b/WindowServer/WSWindowManager.h
index 40841648a3..aabd31b4e7 100644
--- a/WindowServer/WSWindowManager.h
+++ b/WindowServer/WSWindowManager.h
@@ -71,7 +71,7 @@ public:
     void set_resolution(int width, int height);
 
 private:
-    void process_mouse_event(WSMouseEvent&);
+    void process_mouse_event(WSMouseEvent&, WSWindow*& event_window);
     void handle_menu_mouse_event(WSMenu&, WSMouseEvent&);
     void handle_menubar_mouse_event(WSMouseEvent&);
     void handle_titlebar_mouse_event(WSWindow&, WSMouseEvent&);
@@ -79,6 +79,7 @@ private:
     void handle_client_request(WSAPIClientRequest&);
 
     void set_active_window(WSWindow*);
+    void set_hovered_window(WSWindow*);
     template<typename Callback> IterationDecision for_each_visible_window_of_type_from_back_to_front(WSWindowType, Callback);
     template<typename Callback> IterationDecision for_each_visible_window_of_type_from_front_to_back(WSWindowType, Callback);
     template<typename Callback> IterationDecision for_each_visible_window_from_front_to_back(Callback);
@@ -111,7 +112,7 @@ private:
     InlineLinkedList<WSWindow> m_windows_in_order;
 
     WeakPtr<WSWindow> m_active_window;
-
+    WeakPtr<WSWindow> m_hovered_window;
     WeakPtr<WSWindow> m_drag_window;
 
     Point m_drag_origin;