/* * Copyright (c) 1999, 2008, 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. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * 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. */package com.sun.tools.jdi;import com.sun.jdi.*;import java.lang.ref.WeakReference;import java.util.*;class VMState { private final VirtualMachineImpl vm; // Listeners private final List<WeakReference> listeners = new ArrayList<WeakReference>(); // synchronized (this) private boolean notifyingListeners = false; // synchronized (this) /* * Certain information can be cached only when the entire VM is * suspended and there are no pending resumes. The fields below * are used to track whether there are pending resumes. (There * is an assumption that JDWP command ids are increasing over time.) */ private int lastCompletedCommandId = 0; // synchronized (this) private int lastResumeCommandId = 0; // synchronized (this) // This is cached only while the VM is suspended private static class Cache { List<ThreadGroupReference> groups = null; // cached Top Level ThreadGroups List<ThreadReference> threads = null; // cached Threads } private Cache cache = null; // synchronized (this) private static final Cache markerCache = new Cache(); private void disableCache() { synchronized (this) { cache = null; } } private void enableCache() { synchronized (this) { cache = markerCache; } } private Cache getCache() { synchronized (this) { if (cache == markerCache) { cache = new Cache(); } return cache; } } VMState(VirtualMachineImpl vm) { this.vm = vm; } /** * Is the VM currently suspended, for the purpose of caching? * Must be called synchronized on vm.state() */ boolean isSuspended() { return cache != null; } /* * A JDWP command has been completed (reply has been received). * Update data that tracks pending resume commands. */ synchronized void notifyCommandComplete(int id) { lastCompletedCommandId = id; } synchronized void freeze() { if (cache == null && (lastCompletedCommandId >= lastResumeCommandId)) { /* * No pending resumes to worry about. The VM is suspended * and additional state can be cached. Notify all * interested listeners. */ processVMAction(new VMAction(vm, VMAction.VM_SUSPENDED)); enableCache(); } } synchronized PacketStream thawCommand(CommandSender sender) { PacketStream stream = sender.send(); lastResumeCommandId = stream.id(); thaw(); return stream; } /** * All threads are resuming */ void thaw() { thaw(null); } /** * Tell listeners to invalidate suspend-sensitive caches. * If resumingThread != null, then only that thread is being * resumed. */ synchronized void thaw(ThreadReference resumingThread) { if (cache != null) { if ((vm.traceFlags & vm.TRACE_OBJREFS) != 0) { vm.printTrace("Clearing VM suspended cache"); } disableCache(); } processVMAction(new VMAction(vm, resumingThread, VMAction.VM_NOT_SUSPENDED)); } private synchronized void processVMAction(VMAction action) { if (!notifyingListeners) { // Prevent recursion notifyingListeners = true; Iterator iter = listeners.iterator(); while (iter.hasNext()) { WeakReference ref = (WeakReference)iter.next(); VMListener listener = (VMListener)ref.get(); if (listener != null) { boolean keep = true; switch (action.id()) { case VMAction.VM_SUSPENDED: keep = listener.vmSuspended(action); break; case VMAction.VM_NOT_SUSPENDED: keep = listener.vmNotSuspended(action); break; } if (!keep) { iter.remove(); } } else { // Listener is unreachable; clean up iter.remove(); } } notifyingListeners = false; } } synchronized void addListener(VMListener listener) { listeners.add(new WeakReference<VMListener>(listener)); } synchronized boolean hasListener(VMListener listener) { return listeners.contains(listener); } synchronized void removeListener(VMListener listener) { Iterator iter = listeners.iterator(); while (iter.hasNext()) { WeakReference ref = (WeakReference)iter.next(); if (listener.equals(ref.get())) { iter.remove(); break; } } } List<ThreadReference> allThreads() { List<ThreadReference> threads = null; try { Cache local = getCache(); if (local != null) { // may be stale when returned, but not provably so threads = local.threads; } if (threads == null) { threads = Arrays.asList((ThreadReference[])JDWP.VirtualMachine.AllThreads. process(vm).threads); if (local != null) { local.threads = threads; if ((vm.traceFlags & vm.TRACE_OBJREFS) != 0) { vm.printTrace("Caching all threads (count = " + threads.size() + ") while VM suspended"); } } } } catch (JDWPException exc) { throw exc.toJDIException(); } return threads; } List<ThreadGroupReference> topLevelThreadGroups() { List<ThreadGroupReference> groups = null; try { Cache local = getCache(); if (local != null) { groups = local.groups; } if (groups == null) { groups = Arrays.asList( (ThreadGroupReference[])JDWP.VirtualMachine.TopLevelThreadGroups. process(vm).groups); if (local != null) { local.groups = groups; if ((vm.traceFlags & vm.TRACE_OBJREFS) != 0) { vm.printTrace( "Caching top level thread groups (count = " + groups.size() + ") while VM suspended"); } } } } catch (JDWPException exc) { throw exc.toJDIException(); } return groups; }}
/*
* Copyright (c) 1999, 2008, 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. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* 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.
*/
package com.sun.tools.jdi;
import com.sun.jdi.*;
import java.lang.ref.WeakReference;
import java.util.*;
class VMState {
private final VirtualMachineImpl vm;
// Listeners
private final List<WeakReference> listeners = new ArrayList<WeakReference>(); // synchronized (this)
private boolean notifyingListeners = false; // synchronized (this)
/*
* Certain information can be cached only when the entire VM is
* suspended and there are no pending resumes. The fields below
* are used to track whether there are pending resumes. (There
* is an assumption that JDWP command ids are increasing over time.)
*/
private int lastCompletedCommandId = 0; // synchronized (this)
private int lastResumeCommandId = 0; // synchronized (this)
// This is cached only while the VM is suspended
private static class Cache {
List<ThreadGroupReference> groups = null; // cached Top Level ThreadGroups
List<ThreadReference> threads = null; // cached Threads
}
private Cache cache = null; // synchronized (this)
private static final Cache markerCache = new Cache();
private void disableCache() {
synchronized (this) {
cache = null;
}
}
private void enableCache() {
synchronized (this) {
cache = markerCache;
}
}
private Cache getCache() {
synchronized (this) {
if (cache == markerCache) {
cache = new Cache();
}
return cache;
}
}
VMState(VirtualMachineImpl vm) {
this.vm = vm;
}
/**
* Is the VM currently suspended, for the purpose of caching?
* Must be called synchronized on vm.state()
*/
boolean isSuspended() {
return cache != null;
}
/*
* A JDWP command has been completed (reply has been received).
* Update data that tracks pending resume commands.
*/
synchronized void notifyCommandComplete(int id) {
lastCompletedCommandId = id;
}
synchronized void freeze() {
if (cache == null && (lastCompletedCommandId >= lastResumeCommandId)) {
/*
* No pending resumes to worry about. The VM is suspended
* and additional state can be cached. Notify all
* interested listeners.
*/
processVMAction(new VMAction(vm, VMAction.VM_SUSPENDED));
enableCache();
}
}
synchronized PacketStream thawCommand(CommandSender sender) {
PacketStream stream = sender.send();
lastResumeCommandId = stream.id();
thaw();
return stream;
}
/**
* All threads are resuming
*/
void thaw() {
thaw(null);
}
/**
* Tell listeners to invalidate suspend-sensitive caches.
* If resumingThread != null, then only that thread is being
* resumed.
*/
synchronized void thaw(ThreadReference resumingThread) {
if (cache != null) {
if ((vm.traceFlags & vm.TRACE_OBJREFS) != 0) {
vm.printTrace("Clearing VM suspended cache");
}
disableCache();
}
processVMAction(new VMAction(vm, resumingThread, VMAction.VM_NOT_SUSPENDED));
}
private synchronized void processVMAction(VMAction action) {
if (!notifyingListeners) {
// Prevent recursion
notifyingListeners = true;
Iterator iter = listeners.iterator();
while (iter.hasNext()) {
WeakReference ref = (WeakReference)iter.next();
VMListener listener = (VMListener)ref.get();
if (listener != null) {
boolean keep = true;
switch (action.id()) {
case VMAction.VM_SUSPENDED:
keep = listener.vmSuspended(action);
break;
case VMAction.VM_NOT_SUSPENDED:
keep = listener.vmNotSuspended(action);
break;
}
if (!keep) {
iter.remove();
}
} else {
// Listener is unreachable; clean up
iter.remove();
}
}
notifyingListeners = false;
}
}
synchronized void addListener(VMListener listener) {
listeners.add(new WeakReference<VMListener>(listener));
}
synchronized boolean hasListener(VMListener listener) {
return listeners.contains(listener);
}
synchronized void removeListener(VMListener listener) {
Iterator iter = listeners.iterator();
while (iter.hasNext()) {
WeakReference ref = (WeakReference)iter.next();
if (listener.equals(ref.get())) {
iter.remove();
break;
}
}
}
List<ThreadReference> allThreads() {
List<ThreadReference> threads = null;
try {
Cache local = getCache();
if (local != null) {
// may be stale when returned, but not provably so
threads = local.threads;
}
if (threads == null) {
threads = Arrays.asList((ThreadReference[])JDWP.VirtualMachine.AllThreads.
process(vm).threads);
if (local != null) {
local.threads = threads;
if ((vm.traceFlags & vm.TRACE_OBJREFS) != 0) {
vm.printTrace("Caching all threads (count = " +
threads.size() + ") while VM suspended");
}
}
}
} catch (JDWPException exc) {
throw exc.toJDIException();
}
return threads;
}
List<ThreadGroupReference> topLevelThreadGroups() {
List<ThreadGroupReference> groups = null;
try {
Cache local = getCache();
if (local != null) {
groups = local.groups;
}
if (groups == null) {
groups = Arrays.asList(
(ThreadGroupReference[])JDWP.VirtualMachine.TopLevelThreadGroups.
process(vm).groups);
if (local != null) {
local.groups = groups;
if ((vm.traceFlags & vm.TRACE_OBJREFS) != 0) {
vm.printTrace(
"Caching top level thread groups (count = " +
groups.size() + ") while VM suspended");
}
}
}
} catch (JDWPException exc) {
throw exc.toJDIException();
}
return groups;
}
}