gecko/gfx/src/X11Util.h

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#ifndef mozilla_X11Util_h
#define mozilla_X11Util_h

// Utilities common to all X clients, regardless of UI toolkit.

#if defined(MOZ_WIDGET_GTK2)
#  include <gdk/gdkx.h>
#elif defined(MOZ_WIDGET_QT)
// X11/X.h has #define CursorShape 0, but Qt's qnamespace.h defines
//   enum CursorShape { ... }.  Good times!
#undef CursorShape
#  include <QX11Info>
#else
#  error Unknown toolkit
#endif 

#include "nsDebug.h"

namespace mozilla {

/**
 * Return the default X Display created and used by the UI toolkit.
 */
inline Display*
DefaultXDisplay()
{
#if defined(MOZ_WIDGET_GTK2)
  return GDK_DISPLAY();
#elif defined(MOZ_WIDGET_QT)
  return QX11Info::display();
#endif
}

/**
 * Invoke XFree() on a pointer to memory allocated by Xlib (if the
 * pointer is nonnull) when this class goes out of scope.
 */
template<typename T>
struct ScopedXFree
{
  ScopedXFree() : mPtr(NULL) {}
  ScopedXFree(T* aPtr) : mPtr(aPtr) {}

  ~ScopedXFree() { Assign(NULL); }

  ScopedXFree& operator=(T* aPtr) { Assign(aPtr); return *this; }

  operator T*() const { return get(); }
  T* operator->() const { return get(); }
  T* get() const { return mPtr; }

private:
  void Assign(T* aPtr)
  {
    NS_ASSERTION(!mPtr || mPtr != aPtr, "double-XFree() imminent");

    if (mPtr)
      XFree(mPtr);
    mPtr = aPtr;
  }

  T* mPtr;

  // disable these
  ScopedXFree(const ScopedXFree&);
  ScopedXFree& operator=(const ScopedXFree&);
  static void* operator new (size_t);
  static void operator delete (void*);
};

} // namespace mozilla

#endif  // mozilla_X11Util_h