/*

 * 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.

 *

 *

 */

package sun.jvm.hotspot.runtime;

import java.util.*;

import sun.jvm.hotspot.debugger.*;

import sun.jvm.hotspot.oops.*;

import sun.jvm.hotspot.types.*;

public class ObjectMonitor extends VMObject {

  static {

    VM.registerVMInitializedObserver(new Observer() {

        public void update(Observable o, Object data) {

          initialize(VM.getVM().getTypeDataBase());

        }

      });

  }

  private static synchronized void initialize(TypeDataBase db) throws WrongTypeException {

    heap = VM.getVM().getObjectHeap();

    Type type  = db.lookupType("ObjectMonitor");

    sun.jvm.hotspot.types.Field f = type.getField("_header");

    headerFieldOffset = f.getOffset();

    f = type.getField("_object");

    objectFieldOffset = f.getOffset();

    f = type.getField("_owner");

    ownerFieldOffset = f.getOffset();

    f = type.getField("FreeNext");

    FreeNextFieldOffset = f.getOffset();

    countField  = type.getCIntegerField("_count");

    waitersField = type.getCIntegerField("_waiters");

    recursionsField = type.getCIntegerField("_recursions");

  }

  public ObjectMonitor(Address addr) {

    super(addr);

  }

  public Mark header() {

    return new Mark(addr.addOffsetTo(headerFieldOffset));

  }

  // FIXME

  //  void      set_header(markOop hdr);

  // FIXME: must implement and delegate to platform-dependent implementation

  //  public boolean isBusy();

  public boolean isEntered(sun.jvm.hotspot.runtime.Thread current) {

    Address o = owner();

    if (current.threadObjectAddress().equals(o) ||

        current.isLockOwned(o)) {

      return true;

    }

    return false;

  }

  public Address owner() { return addr.getAddressAt(ownerFieldOffset); }

  // FIXME

  //  void      set_owner(void* owner);

  public long    waiters() { return waitersField.getValue(addr); }

  public Address freeNext() { return addr.getAddressAt(FreeNextFieldOffset); }

  // FIXME

  //  void      set_queue(void* owner);

  public long count() { return countField.getValue(addr); }

  // FIXME

  //  void      set_count(intptr_t count);

  public long recursions() { return recursionsField.getValue(addr); }

  public OopHandle object() {

    return addr.getOopHandleAt(objectFieldOffset);

  }

  public long contentions() {

      // refer to objectMonitor_xxx.inline.hpp - contentions definition.

      // for Solaris and Linux, contentions is same as count. for Windows

      // it is different (objectMonitor_win32.inline.hpp)

      long count = count();

      if (VM.getVM().getOS().equals("win32")) {

          // don't count the owner of the monitor

          return count > 0? count - 1 : 0;

      } else {

          // Solaris and Linux

          return count;

      }

  }

  // FIXME

  //  void*     object_addr();

  //  void      set_object(void* obj);

  // The following four either aren't expressed as typed fields in

  // vmStructs.cpp because they aren't strongly typed in the VM, or

  // would confuse the SA's type system.

  private static ObjectHeap    heap;

  private static long          headerFieldOffset;

  private static long          objectFieldOffset;

  private static long          ownerFieldOffset;

  private static long          FreeNextFieldOffset;

  private static CIntegerField countField;

  private static CIntegerField waitersField;

  private static CIntegerField recursionsField;

  // FIXME: expose platform-dependent stuff

}