v8-external.h

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// 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 INCLUDE_V8_EXTERNAL_H_
#define INCLUDE_V8_EXTERNAL_H_
 
#include "v8-value.h"  // NOLINT(build/include_directory)
#include "v8config.h"  // NOLINT(build/include_directory)
 
namespace v8 {
 
class Isolate;
 
using ExternalPointerTypeTag = uint16_t;
 
constexpr ExternalPointerTypeTag kExternalPointerTypeTagDefault = 0;
 
enum InternalExternalPointerTypeTag : uint16_t {
  kFirstInternalExternalPointerTypeTag = V8_EXTERNAL_POINTER_TAG_COUNT - 1,
  kDictionaryValueTag = kFirstInternalExternalPointerTypeTag,
  kLastInternalExternalPointerTypeTag = kDictionaryValueTag,
};
 
static_assert(kLastInternalExternalPointerTypeTag ==
                  V8_EXTERNAL_POINTER_TAG_COUNT - 1,
              "Internal external pointer tags must be the last tags in the "
              "range below V8_EXTERNAL_POINTER_TAG_COUNT.");
 
class V8_EXPORT External : public Value {
 public:
  static Local<External> New(Isolate* isolate, void* value,
                             ExternalPointerTypeTag tag);
  V8_INLINE static External* Cast(Data* value) {
#ifdef V8_ENABLE_CHECKS
    CheckCast(value);
#endif
    return static_cast<External*>(value);
  }
 
  void* Value(ExternalPointerTypeTag tag) const;
 
 private:
  static void CheckCast(v8::Data* obj);
};
 
}  // namespace v8
 
#endif  // INCLUDE_V8_EXTERNAL_H_