108 lines
3.7 KiB
Java
108 lines
3.7 KiB
Java
/*
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* Copyright (c) 2008, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package sun.tracing.dtrace;
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import java.lang.ref.WeakReference;
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import java.lang.ref.ReferenceQueue;
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import java.security.Permission;
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import java.util.HashSet;
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class Activation {
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private SystemResource resource;
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private int referenceCount;
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Activation(String moduleName, DTraceProvider[] providers) {
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SecurityManager security = System.getSecurityManager();
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if (security != null) {
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Permission perm =
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new RuntimePermission("com.sun.tracing.dtrace.createProvider");
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security.checkPermission(perm);
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}
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referenceCount = providers.length;
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for (DTraceProvider p : providers) {
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p.setActivation(this);
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}
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resource = new SystemResource(
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this, JVM.activate(moduleName, providers));
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}
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void disposeProvider(DTraceProvider p) {
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if (--referenceCount == 0) {
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resource.dispose();
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}
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}
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}
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/**
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* The native resource part of an Activation.
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*
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* This holds the native handle.
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*
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* If the user loses a reference to a set of Providers without disposing them,
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* and GC determines the Activation is unreachable, then the next
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* activation or flush call will automatically dispose the unreachable objects
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*
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* The SystemResource instances are creating during activation, and
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* unattached during disposal. When created, they always have a
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* strong reference to them via the {@code resources} static member. Explicit
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* {@code dispose} calls will unregister the native resource and remove
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* references to the SystemResource object. Absent an explicit dispose,
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* when their associated Activation object becomes garbage, the SystemResource
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* object will be enqueued on the reference queue and disposed at the
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* next call to {@code flush}.
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*/
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class SystemResource extends WeakReference<Activation> {
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private long handle;
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private static ReferenceQueue<Activation> referenceQueue =
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referenceQueue = new ReferenceQueue<Activation>();
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static HashSet<SystemResource> resources = new HashSet<SystemResource>();
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SystemResource(Activation activation, long handle) {
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super(activation, referenceQueue);
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this.handle = handle;
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flush();
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resources.add(this);
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}
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void dispose() {
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JVM.dispose(handle);
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resources.remove(this);
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handle = 0;
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}
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static void flush() {
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SystemResource resource = null;
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while ((resource = (SystemResource)referenceQueue.poll()) != null) {
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if (resource.handle != 0) {
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resource.dispose();
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}
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}
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}
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}
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