/*

 * 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.

 *

 */

/**

 *  @test

 *  @bug 4467564

 *  @summary Test the popping of frames in an asynchronous context

 *           (that is, when suspended by the debugger at random points)

 *

 *  @author Robert Field

 *

 *  @run build TestScaffold VMConnection TargetListener TargetAdapter

 *  @run compile -g PopAsynchronousTest.java

 *  @run main PopAsynchronousTest

 */

import com.sun.jdi.*;

import com.sun.jdi.event.*;

import com.sun.jdi.request.*;

import java.util.*;

    /********** target program **********/

class PopAsynchronousTarg {

    static final int N = 30;

    int fibonacci(int n) {

        if (n <= 2) {

            return 1;

        } else {

            return fibonacci(n-1) + fibonacci(n-2);

        }

    }

    void report(int n, int result) {

        System.out.println("fibonacci(" + n + ") = " + result);

    }

    public static void main(String[] args){

        int n = N;

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

        PopAsynchronousTarg pat = new PopAsynchronousTarg();

        pat.report(n, pat.fibonacci(n));

        System.out.println("Goodbye from PopAsynchronousTarg!");

    }

}

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

public class PopAsynchronousTest extends TestScaffold {

    ReferenceType targetClass;

    ThreadReference mainThread;

    int result = -1;

    boolean harassTarget = true;

    Object harassLock = new Object();

    PopAsynchronousTest (String args[]) {

        super(args);

    }

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

        new PopAsynchronousTest(args).startTests();

    }

    /********** event handlers **********/

    public void breakpointReached(BreakpointEvent event) {

        harassTarget = false;

        synchronized(harassLock) {

            try {

                StackFrame frame = event.thread().frame(0);

                LocalVariable lv = frame.visibleVariableByName("result");

                IntegerValue resultV = (IntegerValue)frame.getValue(lv);

                result = resultV.value();

            } catch (Exception exc) {

                exc.printStackTrace(System.err);

                failure("TEST FAILURE: exception " + exc);

            }

        }

    }

    /********** test assist **********/

    class HarassThread extends Thread {

        public void run() {

            int harassCount = 0;

            try {

                int prev = 0;

                int delayTime = 1;

                synchronized(harassLock) {

                    while (harassTarget && (harassCount < 10)) {

                        boolean backoff = true;

                        mainThread.suspend();

                        StackFrame top = mainThread.frame(0);

                        Method meth = top.location().method();

                        String methName = meth.name();

                        if (methName.equals("fibonacci")) {

                            LocalVariable lv = top.visibleVariableByName("n");

                            IntegerValue nV = (IntegerValue)top.getValue(lv);

                            int n = nV.value();

                            if (n != prev) {

                                backoff = false;

                                StackFrame popThis = top;

                                Iterator it = mainThread.frames().iterator();

                                /* pop lowest fibonacci frame */

                                while (it.hasNext()) {

                                    StackFrame frame = (StackFrame)it.next();

                                    if (!frame.location().method().name().equals("fibonacci")) {

                                        break;

                                    }

                                    popThis = frame;

                                }

                                println("popping fibonacci(" + n + ")");

                                mainThread.popFrames(popThis);

                                ++harassCount;

                                prev = n;

                            } else {

                                println("ignoring another fibonacci(" + n + ")");

                            }

                        } else {

                            println("ignoring " + methName);

                        }

                        if (backoff) {

                            delayTime *= 2;

                        } else {

                            delayTime /= 2;

                            if (delayTime < harassCount) {

                                delayTime = harassCount;

                            }

                        }

                        mainThread.resume();

                        println("Delaying for " + delayTime + "ms");

                        Thread.sleep(delayTime);

                    }

                }

            } catch (Exception exc) {

                exc.printStackTrace(System.err);

                failure("TEST FAILURE: exception " + exc);

            }

            println("Harassment complete, count = " + harassCount);

        }

    }

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

    protected void runTests() throws Exception {

        /*

         * Get to the top of main()

         * to determine targetClass and mainThread

         */

        BreakpointEvent bpe = startToMain("PopAsynchronousTarg");

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

        mainThread = bpe.thread();

        EventRequestManager erm = vm().eventRequestManager();

        /*

         * Set event requests

         */

        List meths = targetClass.methodsByName("report");

        Location loc = ((Method)(meths.get(0))).location();

        BreakpointRequest request = erm.createBreakpointRequest(loc);

        request.enable();

        /*

         * start popping wildly away

         */

        (new HarassThread()).start();

        /*

         * resume the target listening for events

         */

        listenUntilVMDisconnect();

        /*

         * check result

         */

        int correct = (new PopAsynchronousTarg()).

            fibonacci(PopAsynchronousTarg.N);

        if (result == correct) {

            println("Got expected result: " + result);

        } else {

            failure("FAIL: expected result: " + correct +

                    ", got: " + result);

        }

        /*

         * deal with results of test

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

         */

        if (!testFailed) {

            println("PopAsynchronousTest: passed");

        } else {

            throw new Exception("PopAsynchronousTest: failed");

        }

    }

}