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    • com.oracle.truffle.js.runtime.builtins.JSFinalizationRegistry Maven / Gradle / Ivy

    /*
 * Copyright (c) 2020, 2024, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * The Universal Permissive License (UPL), Version 1.0
 *
 * Subject to the condition set forth below, permission is hereby granted to any
 * person obtaining a copy of this software, associated documentation and/or
 * data (collectively the "Software"), free of charge and under any and all
 * copyright rights in the Software, and any and all patent rights owned or
 * freely licensable by each licensor hereunder covering either (i) the
 * unmodified Software as contributed to or provided by such licensor, or (ii)
 * the Larger Works (as defined below), to deal in both
 *
 * (a) the Software, and
 *
 * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
 * one is included with the Software each a "Larger Work" to which the Software
 * is contributed by such licensors),
 *
 * without restriction, including without limitation the rights to copy, create
 * derivative works of, display, perform, and distribute the Software and make,
 * use, sell, offer for sale, import, export, have made, and have sold the
 * Software and the Larger Work(s), and to sublicense the foregoing rights on
 * either these or other terms.
 *
 * This license is subject to the following condition:
 *
 * The above copyright notice and either this complete permission notice or at a
 * minimum a reference to the UPL must be included in all copies or substantial
 * portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
package com.oracle.truffle.js.runtime.builtins;

import java.lang.ref.ReferenceQueue;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
import com.oracle.truffle.api.object.Shape;
import com.oracle.truffle.api.strings.TruffleString;
import com.oracle.truffle.js.builtins.FinalizationRegistryPrototypeBuiltins;
import com.oracle.truffle.js.runtime.JSAgent;
import com.oracle.truffle.js.runtime.JSContext;
import com.oracle.truffle.js.runtime.JSRealm;
import com.oracle.truffle.js.runtime.JSRuntime;
import com.oracle.truffle.js.runtime.JobCallback;
import com.oracle.truffle.js.runtime.Strings;
import com.oracle.truffle.js.runtime.objects.AsyncContext;
import com.oracle.truffle.js.runtime.objects.JSDynamicObject;
import com.oracle.truffle.js.runtime.objects.JSObject;
import com.oracle.truffle.js.runtime.objects.JSObjectUtil;
import com.oracle.truffle.js.runtime.objects.Undefined;

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

    public static final JSFinalizationRegistry INSTANCE = new JSFinalizationRegistry();

    public static final TruffleString CLASS_NAME = Strings.constant("FinalizationRegistry");
    public static final TruffleString PROTOTYPE_NAME = Strings.constant("FinalizationRegistry.prototype");

    private JSFinalizationRegistry() {
    }

    public static JSFinalizationRegistryObject create(JSContext context, JSRealm realm, JSDynamicObject proto, JobCallback cleanupCallback) {
        ArrayList cells = new ArrayList<>();
        ReferenceQueue referenceQueue = createReferenceQueue();
        JSObjectFactory factory = context.getFinalizationRegistryFactory();
        var shape = factory.getShape(realm, proto);
        var newObj = factory.initProto(new JSFinalizationRegistryObject(shape, proto, cleanupCallback, cells, referenceQueue), realm, proto);
        JSFinalizationRegistryObject registryObj = factory.trackAllocation(newObj);
        context.registerFinalizationRegistry(registryObj);
        return registryObj;
    }

    @TruffleBoundary
    private static ReferenceQueue createReferenceQueue() {
        return new ReferenceQueue<>();
    }

    @Override
    public JSDynamicObject createPrototype(final JSRealm realm, JSFunctionObject ctor) {
        JSObject prototype = JSObjectUtil.createOrdinaryPrototypeObject(realm);
        JSObjectUtil.putConstructorProperty(prototype, ctor);
        JSObjectUtil.putFunctionsFromContainer(realm, prototype, FinalizationRegistryPrototypeBuiltins.BUILTINS);
        JSObjectUtil.putToStringTag(prototype, CLASS_NAME);
        return prototype;
    }

    @Override
    public Shape makeInitialShape(JSContext context, JSDynamicObject prototype) {
        return JSObjectUtil.getProtoChildShape(prototype, JSFinalizationRegistry.INSTANCE, context);
    }

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

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

    public static boolean isJSFinalizationRegistry(Object obj) {
        return obj instanceof JSFinalizationRegistryObject;
    }

    @Override
    public JSDynamicObject getIntrinsicDefaultProto(JSRealm realm) {
        return realm.getFinalizationRegistryPrototype();
    }

    @TruffleBoundary
    public static void appendToCells(JSFinalizationRegistryObject finalizationRegistry, Object target, Object holdings, Object unregisterToken) {
        List cells = finalizationRegistry.getCells();
        ReferenceQueue queue = finalizationRegistry.getReferenceQueue();
        WeakReference weakTarget = new WeakReference<>(target, queue);
        cells.add(new FinalizationRecord(weakTarget, holdings, unregisterToken));
    }

    @TruffleBoundary
    public static boolean removeFromCells(JSFinalizationRegistryObject finalizationRegistry, Object unregisterToken) {
        List cells = finalizationRegistry.getCells();
        boolean removed = false;
        for (Iterator iterator = cells.iterator(); iterator.hasNext();) {
            FinalizationRecord record = iterator.next();
            if (JSRuntime.isSameValue(record.getUnregisterToken().get(), unregisterToken)) {
                iterator.remove();
                removed = true;
            }
        }
        return removed;
    }

    @TruffleBoundary
    public static void cleanupFinalizationRegistry(JSFinalizationRegistryObject finalizationRegistry, Object callbackArg) {
        JSAgent agent = JSRealm.get(null).getAgent();
        Object callback;
        AsyncContext asyncContext = null;
        if (callbackArg == Undefined.instance) {
            callback = finalizationRegistry.getCleanupCallback().callback();
            asyncContext = finalizationRegistry.getCleanupCallback().asyncContextSnapshot();
        } else {
            callback = callbackArg;
            asyncContext = agent.getAsyncContextMapping();
        }
        FinalizationRecord cell;
        while ((cell = removeCellEmptyTarget(finalizationRegistry)) != null) {
            assert (cell.getWeakRefTarget().get() == null);
            AsyncContext previousContextMapping = agent.asyncContextSwap(asyncContext);
            try {
                JSRuntime.call(callback, Undefined.instance, new Object[]{cell.getHeldValue()});
            } finally {
                agent.asyncContextSwap(previousContextMapping);
            }
        }
    }

    @TruffleBoundary
    public static FinalizationRecord removeCellEmptyTarget(JSFinalizationRegistryObject finalizationRegistry) {
        List cells = finalizationRegistry.getCells();
        for (int i = 0; i < cells.size(); i++) {
            FinalizationRecord record = cells.get(i);
            if (record.getWeakRefTarget().get() == null) {
                cells.remove(i);
                return record;
            }
        }
        return null;
    }

    /**
     * 4.1.3 Execution and 4.1.4.1 HostCleanupFinalizationRegistry.
     */
    public static void hostCleanupFinalizationRegistry(JSFinalizationRegistryObject finalizationRegistry) {
        // if something can be polled, clean up the FinalizationRegistry
        ReferenceQueue queue = finalizationRegistry.getReferenceQueue();
        boolean queueNotEmpty = (queue.poll() != null);
        // Cleared WeakReferences may not appear in ReferenceQueue immediatelly
        // but V8 tests expect the invocation of the callbacks as soon as possible
        // => do not wait for enqueuing in TestV8 mode.
        boolean performCleanup = queueNotEmpty || JSObject.getJSContext(finalizationRegistry).getLanguageOptions().testV8Mode();
        if (performCleanup) {
            // empty the ReferenceQueue
            Object o;
            do {
                o = queue.poll();
            } while (o != null);
            cleanupFinalizationRegistry(finalizationRegistry, Undefined.instance);
        }
    }

}
    
    
    
    

    




    
    
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