Showing the changes to java/pkg/com/sun/tools/jdi/VMState.java (1 of 18352 files). Show all
Unified · Split
| @@ -0,0 +1,245 @@ | |||
| 1 | /* | ||
| 2 | * Copyright (c) 1999, 2008, Oracle and/or its affiliates. All rights reserved. | ||
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | ||
| 4 | * | ||
| 5 | * This code is free software; you can redistribute it and/or modify it | ||
| 6 | * under the terms of the GNU General Public License version 2 only, as | ||
| 7 | * published by the Free Software Foundation. Oracle designates this | ||
| 8 | * particular file as subject to the "Classpath" exception as provided | ||
| 9 | * by Oracle in the LICENSE file that accompanied this code. | ||
| 10 | * | ||
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT | ||
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | ||
| 14 | * version 2 for more details (a copy is included in the LICENSE file that | ||
| 15 | * accompanied this code). | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU General Public License version | ||
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, | ||
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | ||
| 20 | * | ||
| 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | ||
| 22 | * or visit www.oracle.com if you need additional information or have any | ||
| 23 | * questions. | ||
| 24 | */ | ||
| 25 | |||
| 26 | package com.sun.tools.jdi; | ||
| 27 | |||
| 28 | import com.sun.jdi.*; | ||
| 29 | |||
| 30 | import java.lang.ref.WeakReference; | ||
| 31 | import java.util.*; | ||
| 32 | |||
| 33 | class VMState { | ||
| 34 | private final VirtualMachineImpl vm; | ||
| 35 | |||
| 36 | // Listeners | ||
| 37 | private final List<WeakReference> listeners = new ArrayList<WeakReference>(); // synchronized (this) | ||
| 38 | private boolean notifyingListeners = false; // synchronized (this) | ||
| 39 | |||
| 40 | /* | ||
| 41 | * Certain information can be cached only when the entire VM is | ||
| 42 | * suspended and there are no pending resumes. The fields below | ||
| 43 | * are used to track whether there are pending resumes. (There | ||
| 44 | * is an assumption that JDWP command ids are increasing over time.) | ||
| 45 | */ | ||
| 46 | private int lastCompletedCommandId = 0; // synchronized (this) | ||
| 47 | private int lastResumeCommandId = 0; // synchronized (this) | ||
| 48 | |||
| 49 | // This is cached only while the VM is suspended | ||
| 50 | private static class Cache { | ||
| 51 | List<ThreadGroupReference> groups = null; // cached Top Level ThreadGroups | ||
| 52 | List<ThreadReference> threads = null; // cached Threads | ||
| 53 | } | ||
| 54 | |||
| 55 | private Cache cache = null; // synchronized (this) | ||
| 56 | private static final Cache markerCache = new Cache(); | ||
| 57 | |||
| 58 | private void disableCache() { | ||
| 59 | synchronized (this) { | ||
| 60 | cache = null; | ||
| 61 | } | ||
| 62 | } | ||
| 63 | |||
| 64 | private void enableCache() { | ||
| 65 | synchronized (this) { | ||
| 66 | cache = markerCache; | ||
| 67 | } | ||
| 68 | } | ||
| 69 | |||
| 70 | private Cache getCache() { | ||
| 71 | synchronized (this) { | ||
| 72 | if (cache == markerCache) { | ||
| 73 | cache = new Cache(); | ||
| 74 | } | ||
| 75 | return cache; | ||
| 76 | } | ||
| 77 | } | ||
| 78 | |||
| 79 | VMState(VirtualMachineImpl vm) { | ||
| 80 | this.vm = vm; | ||
| 81 | } | ||
| 82 | |||
| 83 | /** | ||
| 84 | * Is the VM currently suspended, for the purpose of caching? | ||
| 85 | * Must be called synchronized on vm.state() | ||
| 86 | */ | ||
| 87 | boolean isSuspended() { | ||
| 88 | return cache != null; | ||
| 89 | } | ||
| 90 | |||
| 91 | /* | ||
| 92 | * A JDWP command has been completed (reply has been received). | ||
| 93 | * Update data that tracks pending resume commands. | ||
| 94 | */ | ||
| 95 | synchronized void notifyCommandComplete(int id) { | ||
| 96 | lastCompletedCommandId = id; | ||
| 97 | } | ||
| 98 | |||
| 99 | synchronized void freeze() { | ||
| 100 | if (cache == null && (lastCompletedCommandId >= lastResumeCommandId)) { | ||
| 101 | /* | ||
| 102 | * No pending resumes to worry about. The VM is suspended | ||
| 103 | * and additional state can be cached. Notify all | ||
| 104 | * interested listeners. | ||
| 105 | */ | ||
| 106 | processVMAction(new VMAction(vm, VMAction.VM_SUSPENDED)); | ||
| 107 | enableCache(); | ||
| 108 | } | ||
| 109 | } | ||
| 110 | |||
| 111 | synchronized PacketStream thawCommand(CommandSender sender) { | ||
| 112 | PacketStream stream = sender.send(); | ||
| 113 | lastResumeCommandId = stream.id(); | ||
| 114 | thaw(); | ||
| 115 | return stream; | ||
| 116 | } | ||
| 117 | |||
| 118 | /** | ||
| 119 | * All threads are resuming | ||
| 120 | */ | ||
| 121 | void thaw() { | ||
| 122 | thaw(null); | ||
| 123 | } | ||
| 124 | |||
| 125 | /** | ||
| 126 | * Tell listeners to invalidate suspend-sensitive caches. | ||
| 127 | * If resumingThread != null, then only that thread is being | ||
| 128 | * resumed. | ||
| 129 | */ | ||
| 130 | synchronized void thaw(ThreadReference resumingThread) { | ||
| 131 | if (cache != null) { | ||
| 132 | if ((vm.traceFlags & vm.TRACE_OBJREFS) != 0) { | ||
| 133 | vm.printTrace("Clearing VM suspended cache"); | ||
| 134 | } | ||
| 135 | disableCache(); | ||
| 136 | } | ||
| 137 | processVMAction(new VMAction(vm, resumingThread, VMAction.VM_NOT_SUSPENDED)); | ||
| 138 | } | ||
| 139 | |||
| 140 | private synchronized void processVMAction(VMAction action) { | ||
| 141 | if (!notifyingListeners) { | ||
| 142 | // Prevent recursion | ||
| 143 | notifyingListeners = true; | ||
| 144 | |||
| 145 | Iterator iter = listeners.iterator(); | ||
| 146 | while (iter.hasNext()) { | ||
| 147 | WeakReference ref = (WeakReference)iter.next(); | ||
| 148 | VMListener listener = (VMListener)ref.get(); | ||
| 149 | if (listener != null) { | ||
| 150 | boolean keep = true; | ||
| 151 | switch (action.id()) { | ||
| 152 | case VMAction.VM_SUSPENDED: | ||
| 153 | keep = listener.vmSuspended(action); | ||
| 154 | break; | ||
| 155 | case VMAction.VM_NOT_SUSPENDED: | ||
| 156 | keep = listener.vmNotSuspended(action); | ||
| 157 | break; | ||
| 158 | } | ||
| 159 | if (!keep) { | ||
| 160 | iter.remove(); | ||
| 161 | } | ||
| 162 | } else { | ||
| 163 | // Listener is unreachable; clean up | ||
| 164 | iter.remove(); | ||
| 165 | } | ||
| 166 | } | ||
| 167 | |||
| 168 | notifyingListeners = false; | ||
| 169 | } | ||
| 170 | } | ||
| 171 | |||
| 172 | synchronized void addListener(VMListener listener) { | ||
| 173 | listeners.add(new WeakReference<VMListener>(listener)); | ||
| 174 | } | ||
| 175 | |||
| 176 | synchronized boolean hasListener(VMListener listener) { | ||
| 177 | return listeners.contains(listener); | ||
| 178 | } | ||
| 179 | |||
| 180 | synchronized void removeListener(VMListener listener) { | ||
| 181 | Iterator iter = listeners.iterator(); | ||
| 182 | while (iter.hasNext()) { | ||
| 183 | WeakReference ref = (WeakReference)iter.next(); | ||
| 184 | if (listener.equals(ref.get())) { | ||
| 185 | iter.remove(); | ||
| 186 | break; | ||
| 187 | } | ||
| 188 | } | ||
| 189 | } | ||
| 190 | |||
| 191 | List<ThreadReference> allThreads() { | ||
| 192 | List<ThreadReference> threads = null; | ||
| 193 | try { | ||
| 194 | Cache local = getCache(); | ||
| 195 | |||
| 196 | if (local != null) { | ||
| 197 | // may be stale when returned, but not provably so | ||
| 198 | threads = local.threads; | ||
| 199 | } | ||
| 200 | if (threads == null) { | ||
| 201 | threads = Arrays.asList((ThreadReference[])JDWP.VirtualMachine.AllThreads. | ||
| 202 | process(vm).threads); | ||
| 203 | if (local != null) { | ||
| 204 | local.threads = threads; | ||
| 205 | if ((vm.traceFlags & vm.TRACE_OBJREFS) != 0) { | ||
| 206 | vm.printTrace("Caching all threads (count = " + | ||
| 207 | threads.size() + ") while VM suspended"); | ||
| 208 | } | ||
| 209 | } | ||
| 210 | } | ||
| 211 | } catch (JDWPException exc) { | ||
| 212 | throw exc.toJDIException(); | ||
| 213 | } | ||
| 214 | return threads; | ||
| 215 | } | ||
| 216 | |||
| 217 | |||
| 218 | List<ThreadGroupReference> topLevelThreadGroups() { | ||
| 219 | List<ThreadGroupReference> groups = null; | ||
| 220 | try { | ||
| 221 | Cache local = getCache(); | ||
| 222 | |||
| 223 | if (local != null) { | ||
| 224 | groups = local.groups; | ||
| 225 | } | ||
| 226 | if (groups == null) { | ||
| 227 | groups = Arrays.asList( | ||
| 228 | (ThreadGroupReference[])JDWP.VirtualMachine.TopLevelThreadGroups. | ||
| 229 | process(vm).groups); | ||
| 230 | if (local != null) { | ||
| 231 | local.groups = groups; | ||
| 232 | if ((vm.traceFlags & vm.TRACE_OBJREFS) != 0) { | ||
| 233 | vm.printTrace( | ||
| 234 | "Caching top level thread groups (count = " + | ||
| 235 | groups.size() + ") while VM suspended"); | ||
| 236 | } | ||
| 237 | } | ||
| 238 | } | ||
| 239 | } catch (JDWPException exc) { | ||
| 240 | throw exc.toJDIException(); | ||
| 241 | } | ||
| 242 | return groups; | ||
| 243 | } | ||
| 244 | |||
| 245 | } | ||