918fe04351
PR-URL: https://github.com/nodejs/node/pull/58070 Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com> Reviewed-By: Darshan Sen <raisinten@gmail.com> Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com> Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
89 lines
2.7 KiB
C++
89 lines
2.7 KiB
C++
// Copyright 2021 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_V8_WEAK_CALLBACK_INFO_H_
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#define INCLUDE_V8_WEAK_CALLBACK_INFO_H_
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#include <cstring>
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#include "cppgc/internal/conditional-stack-allocated.h" // NOLINT(build/include_directory)
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#include "v8config.h" // NOLINT(build/include_directory)
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namespace v8 {
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class Isolate;
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namespace api_internal {
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V8_EXPORT void InternalFieldOutOfBounds(int index);
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} // namespace api_internal
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static constexpr int kInternalFieldsInWeakCallback = 2;
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static constexpr int kEmbedderFieldsInWeakCallback = 2;
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template <typename T>
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class WeakCallbackInfo
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: public cppgc::internal::ConditionalStackAllocatedBase<T> {
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public:
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using Callback = void (*)(const WeakCallbackInfo<T>& data);
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WeakCallbackInfo(Isolate* isolate, T* parameter,
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void* embedder_fields[kEmbedderFieldsInWeakCallback],
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Callback* callback)
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: isolate_(isolate), parameter_(parameter), callback_(callback) {
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memcpy(embedder_fields_, embedder_fields,
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sizeof(embedder_fields[0]) * kEmbedderFieldsInWeakCallback);
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}
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V8_INLINE Isolate* GetIsolate() const { return isolate_; }
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V8_INLINE T* GetParameter() const { return parameter_; }
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V8_INLINE void* GetInternalField(int index) const;
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/**
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* When a weak callback is first invoked the embedders _must_ Reset() the
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* handle which triggered the callback. The handle itself is unusable for
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* anything else. No other V8 API calls may be called in the first callback.
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* Additional work requires scheduling a second invocation via
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* `SetSecondPassCallback()` which will be called some time after all the
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* initial callbacks are processed.
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*
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* The second pass callback is prohibited from executing JavaScript. Embedders
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* should schedule another callback in case this is required.
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*/
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void SetSecondPassCallback(Callback callback) const { *callback_ = callback; }
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private:
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Isolate* isolate_;
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T* parameter_;
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Callback* callback_;
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void* embedder_fields_[kEmbedderFieldsInWeakCallback];
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};
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/**
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* Weakness type for weak handles.
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*/
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enum class WeakCallbackType {
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/**
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* Passes a user-defined void* parameter back to the callback.
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*/
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kParameter,
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/**
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* Passes the first two internal fields of the object back to the callback.
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*/
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kInternalFields,
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};
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template <class T>
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void* WeakCallbackInfo<T>::GetInternalField(int index) const {
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#ifdef V8_ENABLE_CHECKS
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if (index < 0 || index >= kEmbedderFieldsInWeakCallback) {
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api_internal::InternalFieldOutOfBounds(index);
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}
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#endif
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return embedder_fields_[index];
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}
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} // namespace v8
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#endif // INCLUDE_V8_WEAK_CALLBACK_INFO_H_
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