LibGUI+WindowServer: Add support for per-GWidget context menus.

You can now simply assign a GMenu as a GWidget's context menu and it will
automagically pop up on right click. :^)

Servers/WindowServer/WSAPITypes.h

@@ -192,6 +192,7 @@ struct WSAPI_ClientMessage {
         GetWallpaper,
         SetWindowOverrideCursor,
         WM_SetActiveWindow,
+        PopupMenu,
     };
     Type type { Invalid };
     int window_id { -1 };
@@ -214,6 +215,7 @@ struct WSAPI_ClientMessage {
             char shortcut_text[32];
             int shortcut_text_length;
             bool enabled;
+            WSAPI_Point position;
         } menu;
         struct {
             WSAPI_Rect rect;

Servers/WindowServer/WSClientConnection.cpp

@@ -223,6 +223,19 @@ void WSClientConnection::handle_request(const WSAPIAddMenuItemRequest& request)
     post_message(response);
 }
 
+void WSClientConnection::handle_request(const WSAPIPopupMenuRequest& request)
+{
+    int menu_id = request.menu_id();
+    auto position = request.position();
+    auto it = m_menus.find(menu_id);
+    if (it == m_menus.end()) {
+        post_error("WSAPIPopupMenuRequest: Bad menu ID");
+        return;
+    }
+    auto& menu = *(*it).value;
+    menu.popup(position);
+}
+
 void WSClientConnection::handle_request(const WSAPIUpdateMenuItemRequest& request)
 {
     int menu_id = request.menu_id();
@@ -616,6 +629,8 @@ void WSClientConnection::on_request(const WSAPIClientRequest& request)
         return handle_request(static_cast<const WSAPISetWindowOverrideCursorRequest&>(request));
     case WSMessage::WMAPISetActiveWindowRequest:
         return handle_request(static_cast<const WSWMAPISetActiveWindowRequest&>(request));
+    case WSMessage::APIPopupMenuRequest:
+        return handle_request(static_cast<const WSAPIPopupMenuRequest&>(request));
     default:
         break;
     }

Servers/WindowServer/WSClientConnection.h

@@ -70,6 +70,7 @@ private:
     void handle_request(const WSAPIGetWallpaperRequest&);
     void handle_request(const WSAPISetWindowOverrideCursorRequest&);
     void handle_request(const WSWMAPISetActiveWindowRequest&);
+    void handle_request(const WSAPIPopupMenuRequest&);
 
     void post_error(const String&);
 

Servers/WindowServer/WSMenu.cpp

@@ -178,4 +178,14 @@ WSMenuItem* WSMenu::item_at(const Point& position)
 void WSMenu::close()
 {
     WSWindowManager::the().close_menu(*this);
-};
+    if (menu_window())
+        menu_window()->set_visible(false);
+}
+
+void WSMenu::popup(const Point& position)
+{
+    ASSERT(!is_empty());
+    auto& window = ensure_menu_window();
+    window.move_to(position);
+    window.set_visible(true);
+}

Servers/WindowServer/WSMenu.h

@@ -73,6 +73,8 @@ public:
 
     void close();
 
+    void popup(const Point&);
+
 private:
     virtual void on_message(const WSMessage&) override;
 

Servers/WindowServer/WSMessage.h

@@ -57,6 +57,7 @@ public:
         APIGetWallpaperRequest,
         APISetWindowOverrideCursorRequest,
         WMAPISetActiveWindowRequest,
+        APIPopupMenuRequest,
         __End_API_Client_Requests,
     };
 
@@ -189,6 +190,24 @@ private:
     int m_menu_id { 0 };
 };
 
+class WSAPIPopupMenuRequest : public WSAPIClientRequest {
+public:
+    WSAPIPopupMenuRequest(int client_id, int menu_id, const Point& position)
+        : WSAPIClientRequest(WSMessage::APIPopupMenuRequest, client_id)
+        , m_menu_id(menu_id)
+        , m_position(position)
+    {
+    }
+
+    int menu_id() const { return m_menu_id; }
+    Point position() const { return m_position; }
+
+private:
+    int m_menu_id;
+    Point m_position;
+};
+
+
 class WSAPICreateMenuRequest : public WSAPIClientRequest {
 public:
     WSAPICreateMenuRequest(int client_id, const String& text)

Servers/WindowServer/WSMessageLoop.cpp

@@ -290,6 +290,9 @@ void WSMessageLoop::on_receive_from_client(int client_id, const WSAPI_ClientMess
         ASSERT(message.text_length < (ssize_t)sizeof(message.text));
         post_message(client, make<WSAPICreateMenuRequest>(client_id, String(message.text, message.text_length)));
         break;
+    case WSAPI_ClientMessage::Type::PopupMenu:
+        post_message(client, make<WSAPIPopupMenuRequest>(client_id, message.menu.menu_id, message.menu.position));
+        break;
     case WSAPI_ClientMessage::Type::DestroyMenu:
         post_message(client, make<WSAPIDestroyMenuRequest>(client_id, message.menu.menu_id));
         break;