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// Copyright 2016 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_BINDINGS_TRACE_WRAPPER_V8_REFERENCE_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_BINDINGS_TRACE_WRAPPER_V8_REFERENCE_H_
#include <type_traits>
#include <utility>
#include "base/compiler_specific.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
#include "third_party/blink/renderer/platform/wtf/hash_traits.h"
#include "third_party/blink/renderer/platform/wtf/vector_traits.h"
#include "v8/include/v8-cppgc.h"
#include "v8/include/v8-traced-handle.h"
namespace blink {
template <typename T>
using TraceWrapperV8Reference = v8::TracedReference<T>;
} // namespace blink
namespace WTF {
template <typename T>
struct IsTraceable<blink::TraceWrapperV8Reference<T>> {
STATIC_ONLY(IsTraceable);
static const bool value = true;
};
template <typename T>
struct VectorTraits<blink::TraceWrapperV8Reference<T>>
: VectorTraitsBase<blink::TraceWrapperV8Reference<T>> {
STATIC_ONLY(VectorTraits);
static constexpr bool kNeedsDestruction =
!std::is_trivially_destructible<blink::TraceWrapperV8Reference<T>>::value;
// TraceWrapperV8Reference has non-trivial construction/copying/moving.
// However, write barriers in Vector are properly emitted through
// ConstructTraits and as such the type can be trivially initialized, cleared,
// copied, and moved.
static constexpr bool kCanInitializeWithMemset = true;
static constexpr bool kCanClearUnusedSlotsWithMemset = true;
// v8::TracedReference assumes that references uniquely point to an internal
// node.
static constexpr bool kCanCopyWithMemcpy = false;
// TODO(chromium:1322114): Temporarily disable move with memcpy to evaluate
// impact on crashers. Move should always be followed by a clear (non-dtor).
static constexpr bool kCanMoveWithMemcpy = false;
// TraceWrapperV8Reference supports concurrent tracing.
static constexpr bool kCanTraceConcurrently = true;
// Wanted behavior that should not break for performance reasons.
static_assert(!kNeedsDestruction,
"TraceWrapperV8Reference should be trivially destructible.");
};
template <typename T>
struct HashTraits<blink::TraceWrapperV8Reference<T>>
: GenericHashTraits<blink::TraceWrapperV8Reference<T>> {
STATIC_ONLY(HashTraits);
static constexpr bool kCanTraceConcurrently = true;
static constexpr bool kSupportsCompaction = true;
};
} // namespace WTF
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_BINDINGS_TRACE_WRAPPER_V8_REFERENCE_H_
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