cocos_lib/cocos/bindings/jswrapper/v8/ObjectWrap.cpp

/****************************************************************************
 Copyright Joyent, Inc. and other Node contributors.
 Copyright (c) 2021 Xiamen Yaji Software Co., Ltd.

 http://www.cocos.com

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 all copies or substantial portions of the Software.

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#include "ObjectWrap.h"
#include "Object.h"

#if SCRIPT_ENGINE_TYPE == SCRIPT_ENGINE_V8

namespace {
bool gIsIsolateValid = false;
}

namespace se {

/* static */
void ObjectWrap::setIsolateValid(bool valid) {
    gIsIsolateValid = valid;
}

ObjectWrap::ObjectWrap() = default;

ObjectWrap::~ObjectWrap() {
    if (!gIsIsolateValid || persistent().IsEmpty()) {
        return;
    }
    //cjh            CC_ASSERT(persistent().IsNearDeath());
    persistent().ClearWeak();
    persistent().Reset();
}

bool ObjectWrap::init(v8::Local<v8::Object> handle, Object *parent, bool registerWeak) {
    CC_ASSERT(persistent().IsEmpty());
    _parent = parent;
    _registerWeakCallback = registerWeak;
    persistent().Reset(v8::Isolate::GetCurrent(), handle);
    makeWeak();
    return true;
}

void ObjectWrap::setFinalizeCallback(FinalizeFunc finalizeCb) {
    _finalizeCb = finalizeCb;
}

/*static*/
void *ObjectWrap::unwrap(v8::Local<v8::Object> handle, uint32_t fieldIndex) {
    CC_ASSERT(!handle.IsEmpty());
    CC_ASSERT(handle->InternalFieldCount() > 0);
    CC_ASSERT(fieldIndex >= 0 && fieldIndex < 1);
    return handle->GetAlignedPointerFromInternalField(static_cast<int>(fieldIndex));
}
void ObjectWrap::wrap(void *nativeObj, uint32_t fieldIndex) {
    CC_ASSERT(handle()->InternalFieldCount() > 0);
    CC_ASSERT(fieldIndex >= 0 && fieldIndex < 1);
    handle()->SetAlignedPointerInInternalField(static_cast<int>(fieldIndex), nativeObj);
    if (nativeObj) {
        persistent().SetWrapperClassId(MAGIC_CLASS_ID_JSB);
    } else {
        persistent().SetWrapperClassId(0);
    }
}

v8::Local<v8::Object> ObjectWrap::handle() {
    return handle(v8::Isolate::GetCurrent());
}

v8::Local<v8::Object> ObjectWrap::handle(v8::Isolate *isolate) {
    return v8::Local<v8::Object>::New(isolate, persistent());
}

v8::Persistent<v8::Object> &ObjectWrap::persistent() {
    return _handle;
}

void ObjectWrap::makeWeak() {
    // V8 offical documentation said that:
    // kParameter will pass a void* parameter back to the callback, kInternalFields
    // will pass the first two internal fields back to the callback,
    // kFinalizer will pass a void* parameter back, but is invoked before the object is
    // actually collected, so it can be resurrected. In the last case, it is not
    // possible to request a second pass callback.
    // enum class WeakCallbackType { kParameter, kInternalFields, kFinalizer };
    //
    // NOTE: We get random crashes while previewing material in editor's inspector window,
    // the reason is that kFinalizer will trigger weak callback when some assets are
    // still being used, jsbinding code will get a dead se::Object pointer that was
    // freed by weak callback. According V8 documentation, kParameter is a better option.
    if (_registerWeakCallback) {
        persistent().SetWeak(_parent, weakCallback, v8::WeakCallbackType::kParameter);
    } else {
        persistent().SetWeak();
    }
    //        persistent().MarkIndependent();
}

void ObjectWrap::ref() {
    CC_ASSERT(!persistent().IsEmpty());
    persistent().ClearWeak();
    _refs++;
}

void ObjectWrap::unref() {
    if (!gIsIsolateValid) {
        return;
    }
    CC_ASSERT(!persistent().IsEmpty());
    CC_ASSERT(!persistent().IsWeak());
    CC_ASSERT_GT(_refs, 0);
    if (--_refs == 0) {
        makeWeak();
    }
}

/*static*/
void ObjectWrap::weakCallback(const v8::WeakCallbackInfo<Object> &data) {
    Object *seObj = data.GetParameter();
    ObjectWrap *wrap = &seObj->_getWrap();

    CC_ASSERT(wrap->_refs == 0);
    wrap->_handle.Reset();
    if (wrap->_finalizeCb != nullptr) {
        wrap->_finalizeCb(seObj);
    } else {
        CC_ABORT();
    }
}

} // namespace se

#endif // #if SCRIPT_ENGINE_TYPE == SCRIPT_ENGINE_V8