132 lines
4.5 KiB
Java
132 lines
4.5 KiB
Java
/*
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* Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/*
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* @test
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* @bug 8330748
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* @summary Test ByteArrayOutputStream.writeTo releases carrier thread
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* @requires vm.continuations
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* @modules java.base/java.lang:+open
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* @run main WriteToReleasesCarrier
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*/
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import java.io.ByteArrayOutputStream;
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import java.io.IOException;
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import java.io.OutputStream;
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import java.nio.charset.StandardCharsets;
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import java.lang.reflect.Constructor;
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import java.util.Arrays;
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import java.util.concurrent.CountDownLatch;
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import java.util.concurrent.ExecutorService;
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import java.util.concurrent.Executor;
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import java.util.concurrent.Executors;
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import java.util.concurrent.atomic.AtomicBoolean;
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import java.util.concurrent.locks.LockSupport;
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public class WriteToReleasesCarrier {
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public static void main(String[] args) throws Exception {
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byte[] bytes = "Hello".getBytes(StandardCharsets.UTF_8);
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var baos = new ByteArrayOutputStream();
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baos.write(bytes);
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var target = new ParkingOutputStream();
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try (ExecutorService scheduler = Executors.newFixedThreadPool(1)) {
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Thread.Builder builder = virtualThreadBuilder(scheduler);
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var started = new CountDownLatch(1);
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var vthread1 = builder.start(() -> {
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started.countDown();
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try {
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baos.writeTo(target);
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} catch (IOException ioe) { }
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});
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try {
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started.await();
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await(vthread1, Thread.State.WAITING);
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// carrier should be released, use it for another thread
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var executed = new AtomicBoolean();
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var vthread2 = builder.start(() -> {
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executed.set(true);
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});
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vthread2.join();
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if (!executed.get()) {
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throw new RuntimeException("Second virtual thread did not run");
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}
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} finally {
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LockSupport.unpark(vthread1);
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vthread1.join();
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}
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}
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if (!Arrays.equals(target.toByteArray(), bytes)) {
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throw new RuntimeException("Expected bytes not written");
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}
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}
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/**
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* Waits for a thread to get to the expected state.
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*/
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private static void await(Thread thread, Thread.State expectedState) throws Exception {
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Thread.State state = thread.getState();
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while (state != expectedState) {
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Thread.sleep(10);
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state = thread.getState();
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}
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}
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/**
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* An OutputStream that parks when writing.
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*/
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static class ParkingOutputStream extends OutputStream {
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final ByteArrayOutputStream baos = new ByteArrayOutputStream();
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@Override
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public void write(int i) {
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LockSupport.park();
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baos.write(i);
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}
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@Override
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public void write(byte[] b, int off, int len) {
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LockSupport.park();
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baos.write(b, off, len);
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}
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byte[] toByteArray() {
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return baos.toByteArray();
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}
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}
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/**
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* Returns a builder to create virtual threads that use the given scheduler.
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*/
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static Thread.Builder.OfVirtual virtualThreadBuilder(Executor scheduler) throws Exception {
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Class<?> clazz = Class.forName("java.lang.ThreadBuilders$VirtualThreadBuilder");
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Constructor<?> ctor = clazz.getDeclaredConstructor(Executor.class);
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ctor.setAccessible(true);
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return (Thread.Builder.OfVirtual) ctor.newInstance(scheduler);
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}
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}
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