/*

 * Copyright (c) 2005, 2015, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/**

 * @test

 * @bug 6296125

 * @summary  JDI: Disabling an EventRequest can cause a multi-threaded debuggee to hang

 * @author jjh

 *

 * @run build TestScaffold VMConnection TargetListener TargetAdapter

 * @run compile -g TwoThreadsTest.java

 * @run driver TwoThreadsTest

 */

import com.sun.jdi.*;

import com.sun.jdi.event.*;

import com.sun.jdi.request.*;

import java.util.*;

/*

 * This debuggee basically runs two threads each of

 * which loop, hitting a bkpt in each iteration.

 *

 */

class TwoThreadsTarg extends Thread {

    static boolean one = false;

    static String name1 = "Thread 1";

    static String name2 = "Thread 2";

    static int count = 100;

    public static void main(String[] args) {

        System.out.println("Howdy!");

        TwoThreadsTarg t1 = new TwoThreadsTarg(name1);

        TwoThreadsTarg t2 = new TwoThreadsTarg(name2);

        t1.start();

        t2.start();

    }

    public TwoThreadsTarg(String name) {

        super(name);

    }

    public void run() {

        if (getName().equals(name1)) {

            run1();

        } else {

            run2();

        }

    }

    public void bkpt1(int i) {

    }

    public void run1() {

        int i = 0;

        while (i < count) {

            i++;

            bkpt1(i);

        }

    }

    public void bkpt2(int i) {

    }

    public void run2() {

        int i = 0;

        while (i < count) {

            i++;

            bkpt2(i);

        }

    }

}

/********** test program **********/

public class TwoThreadsTest extends TestScaffold {

    ReferenceType targetClass;

    ThreadReference mainThread;

    BreakpointRequest request1;

    BreakpointRequest request2;

    static volatile int bkpts = 0;

    Thread timerThread;

    static int waitTime = 20000;

    TwoThreadsTest (String args[]) {

        super(args);

    }

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

        new TwoThreadsTest(args).startTests();

    }

    /* BreakpointEvent handler */

    public void breakpointReached(BreakpointEvent event) {

        if (bkpts == 0) {

            /*

             * This thread will watch for n secs to go by with no

             * calls to this method.

             */

            timerThread.start();

        }

        synchronized("abc") {

            /*

             * Note that this will most likely never get to

             * the number of times the two bkpt lines in the debuggee

             * are hit because bkpts are lost while they are disabled.

             */

            bkpts++;

        }

        /*

         * The bug occurs when the requests are disabled

         * and then re-enabled during the event handler.

         */

        request1.disable();

        request2.disable();

        /*

         * This code between the disables and enables

         * is just filler that leaves the requests disabled

         * for awhile.  I suppose a sleep could be used instead

         */

        Method mmm = event.location().method();

        List lvlist;

        try {

            lvlist = mmm.variablesByName("i");

        } catch (AbsentInformationException ee) {

            failure("FAILED: can't get local var i");

            return;

        }

        LocalVariable ivar = (LocalVariable)lvlist.get(0);

        ThreadReference thr = event.thread();

        StackFrame sf;

        try {

            sf = thr.frame(0);

        } catch (IncompatibleThreadStateException ee) {

            failure("FAILED: bad thread state");

            return;

        }

        Value ival = sf.getValue(ivar);

        println("Got bkpt at: " + event.location() + ", i = " + ival);

        request1.enable();

        request2.enable();

    }

    /********** test core **********/

    protected void runTests() throws Exception {

        /*

         * Get to the top of main()

         * to determine targetClass and mainThread

         */

        BreakpointEvent bpe = startToMain("TwoThreadsTarg");

        targetClass = bpe.location().declaringType();

        mainThread = bpe.thread();

        EventRequestManager erm = vm().eventRequestManager();

        final Thread mainThread = Thread.currentThread();

        /*

         * Set event requests

         */

        Location loc1 = findMethod(targetClass, "bkpt1", "(I)V").location();

        Location loc2 = findMethod(targetClass, "bkpt2", "(I)V").location();

        request1 = erm.createBreakpointRequest(loc1);

        request2 = erm.createBreakpointRequest(loc2);

        request1.enable();

        request2.enable();

        /*

         * This thread will be started when we get the first bkpt.

         * (Which we always expect to get).

         * It awakens every n seconds and checks to see if we

         * got any breakpoint events while it was asleep.

         */

        timerThread = new Thread("test timer") {

                public void run() {

                    int myBkpts = bkpts;

                    while (true) {

                        try {

                            Thread.sleep(waitTime);

                            System.out.println("bkpts = " + bkpts);

                            if (myBkpts == bkpts) {

                                // no bkpt for 'waitTime' secs

                                failure("failure: Debuggee appears to be hung");

                                vmDisconnected = true;

                                // This awakens the main thread which is

                                // waiting for a VMDisconnect.

                                mainThread.interrupt();

                                break;

                            }

                            myBkpts = bkpts;

                        } catch (InterruptedException ee) {

                            // If the test completes, this occurs.

                            println("timer Interrupted");

                            break;

                        }

                    }

                }

            };

        /*

         * resume the target, listening for events

         */

        listenUntilVMDisconnect();

        timerThread.interrupt();

        /*

         * deal with results of test

         * if anything has called failure("foo") testFailed will be true

         */

        if (!testFailed) {

            println("TwoThreadsTest: passed; bkpts = " + bkpts);

        } else {

            throw new Exception("TwoThreadsTest: failed; bkpts = " + bkpts);

        }

    }

}