chromium/v8/include/cppgc/prefinalizer.h

// Copyright 2020 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef INCLUDE_CPPGC_PREFINALIZER_H_
#define INCLUDE_CPPGC_PREFINALIZER_H_

#include "cppgc/internal/compiler-specific.h"
#include "cppgc/liveness-broker.h"

namespace cppgc {

namespace internal {

class V8_EXPORT PrefinalizerRegistration final {};

}  // namespace internal

/**
 * Macro must be used in the private section of `Class` and registers a
 * prefinalization callback `void Class::PreFinalizer()`. The callback is
 * invoked on garbage collection after the collector has found an object to be
 * dead.
 *
 * Callback properties:
 * - The callback is invoked before a possible destructor for the corresponding
 *   object.
 * - The callback may access the whole object graph, irrespective of whether
 *   objects are considered dead or alive.
 * - The callback is invoked on the same thread as the object was created on.
 *
 * Example:
 * \code
 * class WithPrefinalizer : public GarbageCollected<WithPrefinalizer> {
 *   CPPGC_USING_PRE_FINALIZER(WithPrefinalizer, Dispose);
 *
 *  public:
 *   void Trace(Visitor*) const {}
 *   void Dispose() { prefinalizer_called = true; }
 *   ~WithPrefinalizer() {
 *     // prefinalizer_called == true
 *   }
 *  private:
 *   bool prefinalizer_called = false;
 * };
 * \endcode
 */
#define CPPGC_USING_PRE_FINALIZER(Class, PreFinalizer)

}  // namespace cppgc

#endif  // INCLUDE_CPPGC_PREFINALIZER_H_