6806378ce4
Remove the pre-C++17 implementation of void_t, just use std::void_t now. R=omerkatz@chromium.org Bug: v8:12425 Change-Id: Iabf72f1540ddb4db666e5a74f169f73546241c1f Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3571888 Reviewed-by: Omer Katz <omerkatz@chromium.org> Commit-Queue: Clemens Backes <clemensb@chromium.org> Cr-Commit-Position: refs/heads/main@{#79812}
94 lines
2.6 KiB
C++
94 lines
2.6 KiB
C++
// Copyright 2020 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef INCLUDE_CPPGC_INTERNAL_FINALIZER_TRAIT_H_
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#define INCLUDE_CPPGC_INTERNAL_FINALIZER_TRAIT_H_
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#include <type_traits>
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#include "cppgc/type-traits.h"
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namespace cppgc {
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namespace internal {
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using FinalizationCallback = void (*)(void*);
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template <typename T, typename = void>
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struct HasFinalizeGarbageCollectedObject : std::false_type {};
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template <typename T>
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struct HasFinalizeGarbageCollectedObject<
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T,
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std::void_t<decltype(std::declval<T>().FinalizeGarbageCollectedObject())>>
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: std::true_type {};
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// The FinalizerTraitImpl specifies how to finalize objects.
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template <typename T, bool isFinalized>
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struct FinalizerTraitImpl;
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template <typename T>
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struct FinalizerTraitImpl<T, true> {
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private:
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// Dispatch to custom FinalizeGarbageCollectedObject().
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struct Custom {
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static void Call(void* obj) {
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static_cast<T*>(obj)->FinalizeGarbageCollectedObject();
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}
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};
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// Dispatch to regular destructor.
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struct Destructor {
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static void Call(void* obj) { static_cast<T*>(obj)->~T(); }
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};
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using FinalizeImpl =
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std::conditional_t<HasFinalizeGarbageCollectedObject<T>::value, Custom,
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Destructor>;
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public:
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static void Finalize(void* obj) {
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static_assert(sizeof(T), "T must be fully defined");
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FinalizeImpl::Call(obj);
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}
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};
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template <typename T>
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struct FinalizerTraitImpl<T, false> {
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static void Finalize(void* obj) {
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static_assert(sizeof(T), "T must be fully defined");
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}
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};
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// The FinalizerTrait is used to determine if a type requires finalization and
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// what finalization means.
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template <typename T>
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struct FinalizerTrait {
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private:
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// Object has a finalizer if it has
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// - a custom FinalizeGarbageCollectedObject method, or
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// - a destructor.
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static constexpr bool kNonTrivialFinalizer =
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internal::HasFinalizeGarbageCollectedObject<T>::value ||
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!std::is_trivially_destructible<typename std::remove_cv<T>::type>::value;
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static void Finalize(void* obj) {
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internal::FinalizerTraitImpl<T, kNonTrivialFinalizer>::Finalize(obj);
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}
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public:
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static constexpr bool HasFinalizer() { return kNonTrivialFinalizer; }
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// The callback used to finalize an object of type T.
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static constexpr FinalizationCallback kCallback =
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kNonTrivialFinalizer ? Finalize : nullptr;
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};
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template <typename T>
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constexpr FinalizationCallback FinalizerTrait<T>::kCallback;
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} // namespace internal
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} // namespace cppgc
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#endif // INCLUDE_CPPGC_INTERNAL_FINALIZER_TRAIT_H_
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