subsurface: Rewrite the subsurface tree (#4877)

src/helpers/Subsurface.hpp

@@ -0,0 +1,51 @@
+#pragma once
+
+#include "../defines.hpp"
+#include <vector>
+#include "WLSurface.hpp"
+
+class CWindow;
+
+class CSubsurface {
+  public:
+    // root dummy nodes
+    CSubsurface(CWindow* pOwner);
+
+    // real nodes
+    CSubsurface(wlr_subsurface* pSubsurface, CWindow* pOwner);
+
+    ~CSubsurface();
+
+    Vector2D coordsRelativeToParent();
+    Vector2D coordsGlobal();
+
+    void     onCommit();
+    void     onDestroy();
+    void     onNewSubsurface(wlr_subsurface* pSubsurface);
+    void     onMap();
+    void     onUnmap();
+
+    void     recheckDamageForSubsurfaces();
+
+  private:
+    DYNLISTENER(destroySubsurface);
+    DYNLISTENER(commitSubsurface);
+    DYNLISTENER(newSubsurface);
+    DYNLISTENER(mapSubsurface);
+    DYNLISTENER(unmapSubsurface);
+
+    wlr_subsurface* m_pSubsurface = nullptr;
+    CWLSurface      m_sWLSurface;
+    Vector2D        m_vLastSize = {};
+
+    // if nullptr, means it's a dummy node
+    CSubsurface*                              m_pParent = nullptr;
+
+    CWindow*                                  m_pWindowParent = nullptr;
+
+    std::vector<std::unique_ptr<CSubsurface>> m_vChildren;
+
+    void                                      initSignals();
+    void                                      initExistingSubsurfaces();
+    void                                      checkSiblingDamage();
+};