// Copyright 2021 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 V8_HEAP_CPPGC_OBJECT_VIEW_H_ #define V8_HEAP_CPPGC_OBJECT_VIEW_H_ #include "include/v8config.h" #include "src/heap/cppgc/heap-object-header.h" #include "src/heap/cppgc/heap-page.h" namespace cppgc { namespace internal { // ObjectView allows accessing a header within the bounds of the actual object. // It is not exposed externally and does not keep the underlying object alive. class ObjectView final { public: V8_INLINE explicit ObjectView(const HeapObjectHeader& header); V8_INLINE Address Start() const; V8_INLINE ConstAddress End() const; V8_INLINE size_t Size() const; private: const HeapObjectHeader& header_; const BasePage* base_page_; const bool is_large_object_; }; ObjectView::ObjectView(const HeapObjectHeader& header) : header_(header), base_page_( BasePage::FromPayload(const_cast<HeapObjectHeader*>(&header_))), is_large_object_(header_.IsLargeObject()) { DCHECK_EQ(Start() + Size(), End()); } Address ObjectView::Start() const { return header_.ObjectStart(); } ConstAddress ObjectView::End() const { return is_large_object_ ? LargePage::From(base_page_)->PayloadEnd() : header_.ObjectEnd(); } size_t ObjectView::Size() const { return is_large_object_ ? LargePage::From(base_page_)->ObjectSize() : header_.ObjectSize(); } } // namespace internal } // namespace cppgc #endif // V8_HEAP_CPPGC_OBJECT_VIEW_H_