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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_WEAK_CALLBACK_INFO_H_
- #define INCLUDE_V8_WEAK_CALLBACK_INFO_H_
- #include "v8config.h" // NOLINT(build/include_directory)
- namespace v8 {
- class Isolate;
- namespace api_internal {
- V8_EXPORT void InternalFieldOutOfBounds(int index);
- } // namespace api_internal
- static const int kInternalFieldsInWeakCallback = 2;
- static const int kEmbedderFieldsInWeakCallback = 2;
- template <typename T>
- class WeakCallbackInfo {
- public:
- using Callback = void (*)(const WeakCallbackInfo<T>& data);
- WeakCallbackInfo(Isolate* isolate, T* parameter,
- void* embedder_fields[kEmbedderFieldsInWeakCallback],
- Callback* callback)
- : isolate_(isolate), parameter_(parameter), callback_(callback) {
- for (int i = 0; i < kEmbedderFieldsInWeakCallback; ++i) {
- embedder_fields_[i] = embedder_fields[i];
- }
- }
- V8_INLINE Isolate* GetIsolate() const { return isolate_; }
- V8_INLINE T* GetParameter() const { return parameter_; }
- V8_INLINE void* GetInternalField(int index) const;
- // When first called, the embedder MUST Reset() the Global which triggered the
- // callback. The Global itself is unusable for anything else. No v8 other api
- // calls may be called in the first callback. Should additional work be
- // required, the embedder must set a second pass callback, which will be
- // called after all the initial callbacks are processed.
- // Calling SetSecondPassCallback on the second pass will immediately crash.
- void SetSecondPassCallback(Callback callback) const { *callback_ = callback; }
- private:
- Isolate* isolate_;
- T* parameter_;
- Callback* callback_;
- void* embedder_fields_[kEmbedderFieldsInWeakCallback];
- };
- /**
- * Weakness type for weak handles.
- */
- enum class WeakCallbackType {
- /**
- * Passes a user-defined void* parameter back to the callback.
- */
- kParameter,
- /**
- * Passes the first two internal fields of the object back to the callback.
- */
- kInternalFields,
- /**
- * Passes a user-defined void* parameter back to the callback. Will do so
- * before the object is actually reclaimed, allowing it to be resurrected. In
- * this case it is not possible to set a second-pass callback.
- */
- kFinalizer V8_ENUM_DEPRECATED("Resurrecting finalizers are deprecated "
- "and will not be supported going forward.")
- };
- template <class T>
- void* WeakCallbackInfo<T>::GetInternalField(int index) const {
- #ifdef V8_ENABLE_CHECKS
- if (index < 0 || index >= kEmbedderFieldsInWeakCallback) {
- api_internal::InternalFieldOutOfBounds(index);
- }
- #endif
- return embedder_fields_[index];
- }
- } // namespace v8
- #endif // INCLUDE_V8_WEAK_CALLBACK_INFO_H_
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