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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

/*

 * @test

 * @bug 6460501 6236036 6500694 6490770

 * @summary Repeated failed timed waits shouldn't leak memory

 * @library /test/lib

 * @author Martin Buchholz

 */

import static java.util.concurrent.TimeUnit.MILLISECONDS;

import static java.util.concurrent.TimeUnit.NANOSECONDS;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.OutputStream;

import java.io.PrintStream;

import java.io.Reader;

import java.lang.ref.ReferenceQueue;

import java.lang.ref.WeakReference;

import java.util.concurrent.BlockingQueue;

import java.util.concurrent.Callable;

import java.util.concurrent.CountDownLatch;

import java.util.concurrent.CyclicBarrier;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

import java.util.concurrent.Future;

import java.util.concurrent.LinkedBlockingQueue;

import java.util.concurrent.Semaphore;

import java.util.concurrent.ThreadLocalRandom;

import java.util.concurrent.locks.ReentrantLock;

import java.util.concurrent.locks.ReentrantReadWriteLock;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

import jdk.test.lib.Utils;

public class TimedAcquireLeak {

    static final long LONG_DELAY_MS = Utils.adjustTimeout(10_000);

    static String javahome() {

        String jh = System.getProperty("java.home");

        return (jh.endsWith("jre")) ? jh.substring(0, jh.length() - 4) : jh;

    }

    static final File bin = new File(javahome(), "bin");

    static String javaProgramPath(String programName) {

        return new File(bin, programName).getPath();

    }

    static final String java = javaProgramPath("java");

    static final String jmap = javaProgramPath("jmap");

    static final String jps  = javaProgramPath("jps");

    static String outputOf(Reader r) throws IOException {

        final StringBuilder sb = new StringBuilder();

        final char[] buf = new char[1024];

        int n;

        while ((n = r.read(buf)) > 0)

            sb.append(buf, 0, n);

        return sb.toString();

    }

    static String outputOf(InputStream is) throws IOException {

        return outputOf(new InputStreamReader(is, "UTF-8"));

    }

    static final ExecutorService drainers = Executors.newFixedThreadPool(12);

    static Future<String> futureOutputOf(final InputStream is) {

        return drainers.submit(

            new Callable<String>() { public String call() throws IOException {

                    return outputOf(is); }});}

    static String outputOf(final Process p) {

        try {

            Future<String> outputFuture = futureOutputOf(p.getInputStream());

            Future<String> errorFuture = futureOutputOf(p.getErrorStream());

            final String output = outputFuture.get();

            final String error = errorFuture.get();

            // Check for successful process completion

            equal(error, "");

            equal(p.waitFor(), 0);

            equal(p.exitValue(), 0);

            return output;

        } catch (Throwable t) { unexpected(t); throw new Error(t); }

    }

    static String commandOutputOf(String... cmd) {

        try { return outputOf(new ProcessBuilder(cmd).start()); }

        catch (Throwable t) { unexpected(t); throw new Error(t); }

    }

    // To be called exactly twice by the parent process

    static <T> T rendezvousParent(Process p,

                                  Callable<T> callable) throws Throwable {

        p.getInputStream().read();

        T result = callable.call();

        sendByte(p.getOutputStream());

        return result;

    }

    /** No guarantees, but effective in practice. */

    private static void forceFullGc() {

        long timeoutMillis = 1000L;

        CountDownLatch finalized = new CountDownLatch(1);

        ReferenceQueue<Object> queue = new ReferenceQueue<>();

        WeakReference<Object> ref = new WeakReference<>(

            new Object() { protected void finalize() { finalized.countDown(); }},

            queue);

        try {

            for (int tries = 3; tries--> 0; ) {

                System.gc();

                if (finalized.await(timeoutMillis, MILLISECONDS)

                    && queue.remove(timeoutMillis) != null

                    && ref.get() == null) {

                    System.runFinalization(); // try to pick up stragglers

                    return;

                }

                timeoutMillis *= 4;

            }

        } catch (InterruptedException unexpected) {

            throw new AssertionError("unexpected InterruptedException");

        }

        throw new AssertionError("failed to do a \"full\" gc");

    }

    // To be called exactly twice by the child process

    public static void rendezvousChild() {

        try {

            forceFullGc();

            sendByte(System.out);

            System.in.read();

        } catch (Throwable t) { throw new Error(t); }

    }

    static String match(String s, String regex, int group) {

        Matcher matcher = Pattern.compile(regex).matcher(s);

        matcher.find();

        return matcher.group(group);

    }

    /** It's all about sending a message! */

    static void sendByte(OutputStream s) throws IOException {

        s.write('!');

        s.flush();

    }

    static int objectsInUse(final Process child,

                            final String childPid,

                            final String className) {

        final String regex =

            "(?m)^ *[0-9]+: +([0-9]+) +[0-9]+ +\\Q"+className+"\\E(?:$| )";

        final Callable<Integer> objectsInUse =

            new Callable<Integer>() { public Integer call() {

                Integer i = Integer.parseInt(

                    match(commandOutputOf(jmap, "-histo:live", childPid),

                          regex, 1));

                if (i > 100)

                    System.out.print(

                        commandOutputOf(jmap,

                                        "-dump:file=dump,format=b",

                                        childPid));

                return i;

            }};

        try { return rendezvousParent(child, objectsInUse); }

        catch (Throwable t) { unexpected(t); return -1; }

    }

    static void realMain(String[] args) throws Throwable {

        // jmap doesn't work on Windows

        if (System.getProperty("os.name").startsWith("Windows"))

            return;

        final String childClassName = Job.class.getName();

        final String classToCheckForLeaks = Job.classToCheckForLeaks();

        final String uniqueID =

            String.valueOf(ThreadLocalRandom.current().nextInt(Integer.MAX_VALUE));

        final String[] jobCmd = {

            java, "-Xmx8m", "-XX:+UsePerfData",

            "-classpath", System.getProperty("test.class.path"),

            childClassName, uniqueID

        };

        final Process p = new ProcessBuilder(jobCmd).start();

        // Ensure subprocess jvm has started, so that jps can find it

        p.getInputStream().read();

        sendByte(p.getOutputStream());

        final String childPid =

            match(commandOutputOf(jps, "-m"),

                  "(?m)^ *([0-9]+) +\\Q"+childClassName+"\\E *"+uniqueID+"$", 1);

        final int n0 = objectsInUse(p, childPid, classToCheckForLeaks);

        final int n1 = objectsInUse(p, childPid, classToCheckForLeaks);

        equal(p.waitFor(), 0);

        equal(p.exitValue(), 0);

        failed += p.exitValue();

        // Check that no objects were leaked.

        //

        // TODO: This test is very brittle, depending on current JDK

        // implementation, and needing occasional adjustment.

        System.out.printf("%d -> %d%n", n0, n1);

        // Almost always n0 == n1

        // Maximum jitter observed in practice is 10 -> 17

        check(Math.abs(n1 - n0) < 10);

        check(n1 < 25);

        drainers.shutdown();

        if (!drainers.awaitTermination(LONG_DELAY_MS, MILLISECONDS)) {

            drainers.shutdownNow(); // last resort

            throw new AssertionError("thread pool did not terminate");

        }

    }

    //----------------------------------------------------------------

    // The main class of the child process.

    // Job's job is to:

    // - provide the name of a class to check for leaks.

    // - call rendezvousChild exactly twice, while quiescent.

    // - in between calls to rendezvousChild, run code that may leak.

    //----------------------------------------------------------------

    public static class Job {

        static String classToCheckForLeaks() {

            return

                "java.util.concurrent.locks.AbstractQueuedSynchronizer$Node";

        }

        public static void main(String[] args) throws Throwable {

            // Synchronize with parent process, so that jps can find us

            sendByte(System.out);

            System.in.read();

            final ReentrantLock lock = new ReentrantLock();

            lock.lock();

            final ReentrantReadWriteLock rwlock

                = new ReentrantReadWriteLock();

            final ReentrantReadWriteLock.ReadLock readLock

                = rwlock.readLock();

            final ReentrantReadWriteLock.WriteLock writeLock

                = rwlock.writeLock();

            rwlock.writeLock().lock();

            final BlockingQueue<Object> q = new LinkedBlockingQueue<>();

            final Semaphore fairSem = new Semaphore(0, true);

            final Semaphore unfairSem = new Semaphore(0, false);

            //final int threads =

            //rnd.nextInt(Runtime.getRuntime().availableProcessors() + 1) + 1;

            final int threads = 3;

            // On Linux, this test runs very slowly for some reason,

            // so use a smaller number of iterations.

            // Solaris can handle 1 << 18.

            // On the other hand, jmap is much slower on Solaris...

            final int iterations = 1 << 8;

            final CyclicBarrier cb = new CyclicBarrier(threads+1);

            for (int i = 0; i < threads; i++)

                new Thread() { public void run() {

                    try {

                        final ThreadLocalRandom rnd = ThreadLocalRandom.current();

                        for (int j = 0; j < iterations; j++) {

                            if (j == iterations/10 || j == iterations - 1) {

                                cb.await(); // Quiesce

                                cb.await(); // Resume

                            }

                            //int t = rnd.nextInt(2000);

                            int t = rnd.nextInt(900);

                            check(! lock.tryLock(t, NANOSECONDS));

                            check(! readLock.tryLock(t, NANOSECONDS));

                            check(! writeLock.tryLock(t, NANOSECONDS));

                            equal(null, q.poll(t, NANOSECONDS));

                            check(! fairSem.tryAcquire(t, NANOSECONDS));

                            check(! unfairSem.tryAcquire(t, NANOSECONDS));

                        }

                    } catch (Throwable t) { unexpected(t); }

                }}.start();

            cb.await();         // Quiesce

            rendezvousChild();  // Measure

            cb.await();         // Resume

            cb.await();         // Quiesce

            rendezvousChild();  // Measure

            cb.await();         // Resume

            System.exit(failed);

        }

        // If something goes wrong, we might never see it, since IO

        // streams are connected to the parent.  So we need a special

        // purpose print method to debug Jobs.

        static void debugPrintf(String format, Object... args) {

            try {

                new PrintStream(new FileOutputStream("/dev/tty"))

                    .printf(format, args);

            } catch (Throwable t) { throw new Error(t); }

        }

    }

    //--------------------- Infrastructure ---------------------------

    static volatile int passed = 0, failed = 0;

    static void pass() {passed++;}

    static void fail() {failed++; Thread.dumpStack();}

    static void fail(String msg) {System.out.println(msg); fail();}

    static void unexpected(Throwable t) {failed++; t.printStackTrace();}

    static void check(boolean cond) {if (cond) pass(); else fail();}

    static void check(boolean cond, String m) {if (cond) pass(); else fail(m);}

    static void equal(Object x, Object y) {

        if (x == null ? y == null : x.equals(y)) pass();

        else fail(x + " not equal to " + y);}

    public static void main(String[] args) throws Throwable {

        try {realMain(args);} catch (Throwable t) {unexpected(t);}

        System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);

        if (failed > 0) throw new AssertionError("Some tests failed");}

}