Showing the changes to java/pkg/com/sun/tools/jdi/VMState.java (1 of 18352 files). Show all
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| 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 | +} | |