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 * The Universal Permissive License (UPL), Version 1.0
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 * (a) the Software, and
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 * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
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 * Software and the Larger Work(s), and to sublicense the foregoing rights on
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package com.oracle.truffle.js.runtime.builtins;

import java.lang.ref.WeakReference;

import com.oracle.truffle.api.object.DynamicObject;
import com.oracle.truffle.api.object.Shape;
import com.oracle.truffle.js.builtins.WeakRefPrototypeBuiltins;
import com.oracle.truffle.js.runtime.JSContext;
import com.oracle.truffle.js.runtime.JSRealm;
import com.oracle.truffle.js.runtime.objects.JSObjectUtil;

public final class JSWeakRef extends JSNonProxy implements JSConstructorFactory.Default, PrototypeSupplier {

    public static final JSWeakRef INSTANCE = new JSWeakRef();

    public static final String CLASS_NAME = "WeakRef";
    public static final String PROTOTYPE_NAME = "WeakRef.prototype";

    private JSWeakRef() {
    }

    public static DynamicObject create(JSContext context, Object referent) {
        TruffleWeakReference<Object> weakReference = new TruffleWeakReference<>(referent);
        JSRealm realm = context.getRealm();
        JSObjectFactory factory = context.getWeakRefFactory();
        DynamicObject obj = factory.initProto(new JSWeakRefObject(factory.getShape(realm), weakReference), realm);
        assert isJSWeakRef(obj);
        // Used for KeepDuringJob(target) in the specification
        context.addWeakRefTargetToSet(referent);
        return context.trackAllocation(obj);
    }

    public static TruffleWeakReference<?> getInternalWeakRef(DynamicObject obj) {
        assert isJSWeakRef(obj);
        return ((JSWeakRefObject) obj).getWeakReference();
    }

    @Override
    public DynamicObject createPrototype(final JSRealm realm, DynamicObject ctor) {
        JSContext ctx = realm.getContext();
        DynamicObject prototype = JSObjectUtil.createOrdinaryPrototypeObject(realm);
        JSObjectUtil.putConstructorProperty(ctx, prototype, ctor);
        JSObjectUtil.putFunctionsFromContainer(realm, prototype, WeakRefPrototypeBuiltins.BUILTINS);
        JSObjectUtil.putToStringTag(prototype, CLASS_NAME);
        return prototype;
    }

    @Override
    public Shape makeInitialShape(JSContext context, DynamicObject prototype) {
        Shape initialShape = JSObjectUtil.getProtoChildShape(prototype, JSWeakRef.INSTANCE, context);
        return initialShape;
    }

    public static JSConstructor createConstructor(JSRealm realm) {
        return INSTANCE.createConstructorAndPrototype(realm);
    }

    @Override
    public String getClassName() {
        return CLASS_NAME;
    }

    @Override
    public String getClassName(DynamicObject object) {
        return getClassName();
    }

    @Override
    public String toDisplayStringImpl(DynamicObject obj, int depth, boolean allowSideEffects, JSContext context) {
        return "[" + getClassName() + "]";
    }

    public static boolean isJSWeakRef(Object obj) {
        return obj instanceof JSWeakRefObject;
    }

    @Override
    public DynamicObject getIntrinsicDefaultProto(JSRealm realm) {
        return realm.getWeakRefPrototype();
    }

    public static final class TruffleWeakReference<T> extends WeakReference<T> {

        public TruffleWeakReference(T t) {
            super(t);
        }

    }
}