prefinalizer.h

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// 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/accessors.h"
#include "cppgc/internal/compiler-specific.h"
#include "cppgc/internal/prefinalizer-handler.h"
#include "cppgc/liveness-broker.h"
#include "cppgc/macros.h"
 
namespace cppgc {
 
namespace internal {
 
template <typename T>
class PrefinalizerRegistration final {
 public:
  explicit PrefinalizerRegistration(T* self) {
    static_assert(sizeof(&T::InvokePreFinalizer) > 0,
                  "USING_PRE_FINALIZER(T) must be defined.");
 
    cppgc::internal::PreFinalizerRegistrationDispatcher::RegisterPrefinalizer(
        internal::GetHeapFromPayload(self), {self, T::InvokePreFinalizer});
  }
 
  void* operator new(size_t, void* location) = delete;
  void* operator new(size_t) = delete;
};
 
}  // namespace internal
 
#define CPPGC_USING_PRE_FINALIZER(Class, PreFinalizer)
 public:
  static bool InvokePreFinalizer(const LivenessBroker& liveness_broker,
                                 void* object) {
    static_assert(internal::IsGarbageCollectedTypeV<Class>,
                  "Only garbage collected objects can have prefinalizers");
    Class* self = static_cast<Class*>(object);
    if (liveness_broker.IsHeapObjectAlive(self)) return false;
    self->Class::PreFinalizer();
    return true;
  }
 
 private:
  CPPGC_NO_UNIQUE_ADDRESS internal::PrefinalizerRegistration<Class>
      prefinalizer_dummy_{this};
  friend class internal::__thisIsHereToForceASemicolonAfterThisMacro
 
}  // namespace cppgc
 
#endif  // INCLUDE_CPPGC_PREFINALIZER_H_