WindowServer: Add Window "modified" state

This will be used to track which windows contain some kind of unsaved
data that the user may want some help remembering to save. :^)

Userland/Services/WindowServer/ClientConnection.cpp

@@ -903,4 +903,26 @@ OwnPtr<Messages::WindowServer::GetScreenBitmapResponse> ClientConnection::handle
     return make<Messages::WindowServer::GetScreenBitmapResponse>(bitmap.to_shareable_bitmap());
 }
 
+OwnPtr<Messages::WindowServer::IsWindowModifiedResponse> ClientConnection::handle(Messages::WindowServer::IsWindowModified const& message)
+{
+    auto it = m_windows.find(message.window_id());
+    if (it == m_windows.end()) {
+        did_misbehave("IsWindowModified: Bad window ID");
+        return {};
+    }
+    auto& window = *it->value;
+    return make<Messages::WindowServer::IsWindowModifiedResponse>(window.is_modified());
+}
+
+void ClientConnection::handle(Messages::WindowServer::SetWindowModified const& message)
+{
+    auto it = m_windows.find(message.window_id());
+    if (it == m_windows.end()) {
+        did_misbehave("SetWindowModified: Bad window ID");
+        return;
+    }
+    auto& window = *it->value;
+    window.set_modified(message.modified());
+}
+
 }

Userland/Services/WindowServer/ClientConnection.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -146,6 +146,8 @@ private:
     virtual OwnPtr<Messages::WindowServer::GetScreenBitmapResponse> handle(const Messages::WindowServer::GetScreenBitmap&) override;
     virtual OwnPtr<Messages::WindowServer::SetDoubleClickSpeedResponse> handle(const Messages::WindowServer::SetDoubleClickSpeed&) override;
     virtual OwnPtr<Messages::WindowServer::GetDoubleClickSpeedResponse> handle(const Messages::WindowServer::GetDoubleClickSpeed&) override;
+    virtual void handle(Messages::WindowServer::SetWindowModified const&) override;
+    virtual OwnPtr<Messages::WindowServer::IsWindowModifiedResponse> handle(Messages::WindowServer::IsWindowModified const&) override;
 
     Window* window_from_id(i32 window_id);
 

Userland/Services/WindowServer/Window.cpp

@@ -992,4 +992,13 @@ void Window::invalidate_menubar()
     frame().invalidate();
 }
 
+void Window::set_modified(bool modified)
+{
+    if (m_modified == modified)
+        return;
+
+    m_modified = modified;
+    invalidate();
+}
+
 }

Userland/Services/WindowServer/Window.h

@@ -76,6 +76,9 @@ public:
     Window(Core::Object&, WindowType);
     virtual ~Window() override;
 
+    bool is_modified() const { return m_modified; }
+    void set_modified(bool);
+
     void popup_window_menu(const Gfx::IntPoint&, WindowMenuDefaultAction);
     void handle_window_menu_action(WindowMenuAction);
     void window_menu_activate_default();
@@ -397,6 +400,7 @@ private:
     int m_minimize_animation_step { -1 };
     int m_progress { -1 };
     bool m_should_show_menubar { true };
+    bool m_modified { false };
 };
 
 }

Userland/Services/WindowServer/WindowServer.ipc

@@ -56,6 +56,9 @@ endpoint WindowServer
 
     SetWindowProgress(i32 window_id, i32 progress) =|
 
+    SetWindowModified(i32 window_id, bool modified) =|
+    IsWindowModified(i32 window_id) => (bool modified)
+
     SetWindowRect(i32 window_id, Gfx::IntRect rect) => (Gfx::IntRect rect)
     GetWindowRect(i32 window_id) => (Gfx::IntRect rect)