gecko-dev/xpcom/base/nsWeakReference.h

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef nsWeakReference_h__
#define nsWeakReference_h__

// nsWeakReference.h

// See mfbt/WeakPtr.h for a more typesafe C++ implementation of weak references

#include "nsIWeakReferenceUtils.h"

class nsWeakReference;

class nsSupportsWeakReference : public nsISupportsWeakReference
{
public:
  nsSupportsWeakReference() : mProxy(0) {}

  NS_DECL_NSISUPPORTSWEAKREFERENCE

protected:
  inline ~nsSupportsWeakReference();

private:
  friend class nsWeakReference;

  // Called (only) by an |nsWeakReference| from _its_ dtor.
  // The thread safety check is made by the caller.
  void NoticeProxyDestruction() { mProxy = nullptr; }

  nsWeakReference* MOZ_NON_OWNING_REF mProxy;

protected:

  void ClearWeakReferences();
  bool HasWeakReferences() const { return !!mProxy; }
};

inline
nsSupportsWeakReference::~nsSupportsWeakReference()
{
  ClearWeakReferences();
}

#endif