/*

 * Copyright 2012 SAP AG.  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 FieldMonitor.java

 * @bug 7158988

 * @summary verify jvm does not crash while debugging

 * @run shell TestFieldMonitor.sh

 * @author axel.siebenborn@sap.com

 */

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.OutputStream;

import java.io.OutputStreamWriter;

import java.io.Reader;

import java.io.Writer;

import java.util.Iterator;

import java.util.List;

import java.util.Map;

import com.sun.jdi.Bootstrap;

import com.sun.jdi.Field;

import com.sun.jdi.ReferenceType;

import com.sun.jdi.VirtualMachine;

import com.sun.jdi.connect.Connector;

import com.sun.jdi.connect.IllegalConnectorArgumentsException;

import com.sun.jdi.connect.LaunchingConnector;

import com.sun.jdi.connect.VMStartException;

import com.sun.jdi.event.ClassPrepareEvent;

import com.sun.jdi.event.Event;

import com.sun.jdi.event.EventQueue;

import com.sun.jdi.event.EventSet;

import com.sun.jdi.event.ModificationWatchpointEvent;

import com.sun.jdi.event.VMDeathEvent;

import com.sun.jdi.event.VMDisconnectEvent;

import com.sun.jdi.request.ClassPrepareRequest;

import com.sun.jdi.request.EventRequest;

import com.sun.jdi.request.EventRequestManager;

import com.sun.jdi.request.ModificationWatchpointRequest;

public class FieldMonitor {

  public static final String CLASS_NAME = "TestPostFieldModification";

  public static final String FIELD_NAME = "value";

  public static final String ARGUMENTS = "-Xshare:off -XX:+PrintGC";

  public static void main(String[] args)

      throws IOException, InterruptedException {

    StringBuffer sb = new StringBuffer();

    for (int i=0; i < args.length; i++) {

        sb.append(' ');

        sb.append(args[i]);

    }

    //VirtualMachine vm = launchTarget(sb.toString());

    VirtualMachine vm = launchTarget(CLASS_NAME);

    System.out.println("Vm launched");

    // set watch field on already loaded classes

    List<ReferenceType> referenceTypes = vm

        .classesByName(CLASS_NAME);

    for (ReferenceType refType : referenceTypes) {

      addFieldWatch(vm, refType);

    }

    // watch for loaded classes

    addClassWatch(vm);

    // process events

    EventQueue eventQueue = vm.eventQueue();

    // resume the vm

    Process process = vm.process();

    // Copy target's output and error to our output and error.

    Thread outThread = new StreamRedirectThread("out reader", process.getInputStream());

    Thread errThread = new StreamRedirectThread("error reader", process.getErrorStream());

    errThread.start();

    outThread.start();

    vm.resume();

    boolean connected = true;

    while (connected) {

      EventSet eventSet = eventQueue.remove();

      for (Event event : eventSet) {

        if (event instanceof VMDeathEvent

            || event instanceof VMDisconnectEvent) {

          // exit

          connected = false;

        } else if (event instanceof ClassPrepareEvent) {

          // watch field on loaded class

          System.out.println("ClassPrepareEvent");

          ClassPrepareEvent classPrepEvent = (ClassPrepareEvent) event;

          ReferenceType refType = classPrepEvent

              .referenceType();

          addFieldWatch(vm, refType);

        } else if (event instanceof ModificationWatchpointEvent) {

          System.out.println("sleep for 500 ms");

          Thread.sleep(500);

          System.out.println("resume...");

          ModificationWatchpointEvent modEvent = (ModificationWatchpointEvent) event;

          System.out.println("old="

              + modEvent.valueCurrent());

          System.out.println("new=" + modEvent.valueToBe());

          System.out.println();

        }

      }

      eventSet.resume();

    }

    // Shutdown begins when event thread terminates

    try {

        errThread.join(); // Make sure output is forwarded

        outThread.join();

    } catch (InterruptedException exc) {

        // we don't interrupt

    }

  }

  /**

   * Find a com.sun.jdi.CommandLineLaunch connector

   */

  static LaunchingConnector findLaunchingConnector() {

    List <Connector> connectors = Bootstrap.virtualMachineManager().allConnectors();

    Iterator <Connector> iter = connectors.iterator();

    while (iter.hasNext()) {

      Connector connector = iter.next();

      if (connector.name().equals("com.sun.jdi.CommandLineLaunch")) {

        return (LaunchingConnector)connector;

      }

    }

    throw new Error("No launching connector");

  }

  /**

   * Return the launching connector's arguments.

   */

 static Map <String,Connector.Argument> connectorArguments(LaunchingConnector connector, String mainArgs) {

      Map<String,Connector.Argument> arguments = connector.defaultArguments();

      for (String key : arguments.keySet()) {

        System.out.println(key);

      }

      Connector.Argument mainArg = (Connector.Argument)arguments.get("main");

      if (mainArg == null) {

          throw new Error("Bad launching connector");

      }

      mainArg.setValue(mainArgs);

      Connector.Argument optionsArg = (Connector.Argument)arguments.get("options");

      if (optionsArg == null) {

        throw new Error("Bad launching connector");

      }

      optionsArg.setValue(ARGUMENTS);

      return arguments;

  }

 static VirtualMachine launchTarget(String mainArgs) {

    LaunchingConnector connector = findLaunchingConnector();

    Map  arguments = connectorArguments(connector, mainArgs);

    try {

        return (VirtualMachine) connector.launch(arguments);

    } catch (IOException exc) {

        throw new Error("Unable to launch target VM: " + exc);

    } catch (IllegalConnectorArgumentsException exc) {

        throw new Error("Internal error: " + exc);

    } catch (VMStartException exc) {

        throw new Error("Target VM failed to initialize: " +

                        exc.getMessage());

    }

}

  private static void addClassWatch(VirtualMachine vm) {

    EventRequestManager erm = vm.eventRequestManager();

    ClassPrepareRequest classPrepareRequest = erm

        .createClassPrepareRequest();

    classPrepareRequest.addClassFilter(CLASS_NAME);

    classPrepareRequest.setEnabled(true);

  }

  private static void addFieldWatch(VirtualMachine vm,

      ReferenceType refType) {

    EventRequestManager erm = vm.eventRequestManager();

    Field field = refType.fieldByName(FIELD_NAME);

    ModificationWatchpointRequest modificationWatchpointRequest = erm

        .createModificationWatchpointRequest(field);

    modificationWatchpointRequest.setSuspendPolicy(EventRequest.SUSPEND_EVENT_THREAD);

    modificationWatchpointRequest.setEnabled(true);

  }

}

class StreamRedirectThread extends Thread {

  private final BufferedReader in;

  private static final int BUFFER_SIZE = 2048;

  /**

   * Set up for copy.

   * @param name  Name of the thread

   * @param in    Stream to copy from

   * @param out   Stream to copy to

   */

  StreamRedirectThread(String name, InputStream in) {

    super(name);

    this.in = new BufferedReader(new InputStreamReader(in));

  }

  /**

   * Copy.

   */

  public void run() {

    try {

      String line;

        while ((line = in.readLine ()) != null) {

          System.out.println ("testvm: " + line);

      }

     System.out.flush();

    } catch(IOException exc) {

      System.err.println("Child I/O Transfer - " + exc);

    }

  }

}