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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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/**
 * @test
 * @summary Test synchronization by virtual thread on synchronized native method
 * @library /test/lib
 * @run main/othervm/native -Xint JucSyncNativeMethod
 * @run main/othervm/native -Xcomp -XX:CompileOnly=JucSyncNativeMethod::runFromNative JucSyncNativeMethod
 */

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executors;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.locks.LockSupport;
import java.util.concurrent.atomic.AtomicInteger;

import jdk.test.lib.Asserts;

import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

public class JucSyncNativeMethod {
    static final Lock lock = new ReentrantLock();
    static final int VTHREAD_COUNT = Runtime.getRuntime().availableProcessors() - 1; // 1 is used for Main
    static AtomicInteger counter = new AtomicInteger(0);

    private static native void runFromNative(Runnable runnable);

    private static void runUpcall(Runnable runnable) {
        lock.lock();
        runnable.run();
        lock.unlock();
    }

    public static void main(String[] args) throws Exception {
        System.loadLibrary("JucSyncNativeMethod");
        Thread t = Thread.ofVirtual().name("Main").start(()->{
            Thread[] vthreads = new Thread[VTHREAD_COUNT];
            try {
                startVThreads(vthreads);
                // Wait for all vthreads to finish
                for (int i = 0; i < VTHREAD_COUNT; i++) {
                    vthreads[i].join();
                }
            } catch (Exception e) {
                // TODO: handle exception
            }
            Asserts.assertTrue(counter.get() == VTHREAD_COUNT, counter.get() + "!=" + VTHREAD_COUNT);
        });
        t.join();
    }

    private static void startVThreads(Thread[] vthreads) throws Exception {
        lock.lock();
        for (int i = 0; i < VTHREAD_COUNT; i++) {
            var started = new CountDownLatch(1);
            var vthread = Thread.ofVirtual().name("vthread-"+(i+1)).start(() -> {
                started.countDown();
                runFromNative(() -> LockSupport.parkNanos(1));
                counter.getAndIncrement();
            });
            // wait for thread to start
            started.await();
            await(vthread, Thread.State.WAITING);
            vthreads[i] = vthread;
        }
        runFromNative(() -> LockSupport.parkNanos(1));
        lock.unlock();
    }

    private static void await(Thread thread, Thread.State expectedState) {
        Thread.State state = thread.getState();
        while (state != expectedState) {
            Asserts.assertTrue(state != Thread.State.TERMINATED, "Thread has terminated");
            Thread.yield();
            state = thread.getState();
        }
    }
}