| /* |
| * Copyright (c) 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 sun.tracing.dtrace; |
| |
| import java.lang.ref.WeakReference; |
| import java.lang.ref.ReferenceQueue; |
| import java.security.Permission; |
| import java.util.HashSet; |
| |
| class Activation { |
| private SystemResource resource; |
| private int referenceCount; |
| |
| Activation(String moduleName, DTraceProvider[] providers) { |
| SecurityManager security = System.getSecurityManager(); |
| if (security != null) { |
| Permission perm = |
| new RuntimePermission("com.sun.tracing.dtrace.createProvider"); |
| security.checkPermission(perm); |
| } |
| referenceCount = providers.length; |
| for (DTraceProvider p : providers) { |
| p.setActivation(this); |
| } |
| resource = new SystemResource( |
| this, JVM.activate(moduleName, providers)); |
| } |
| |
| void disposeProvider(DTraceProvider p) { |
| if (--referenceCount == 0) { |
| resource.dispose(); |
| } |
| } |
| } |
| |
| /** |
| * The native resource part of an Activation. |
| * |
| * This holds the native handle. |
| * |
| * If the user loses a reference to a set of Providers without disposing them, |
| * and GC determines the Activation is unreachable, then the next |
| * activation or flush call will automatically dispose the unreachable objects |
| * |
| * The SystemResource instances are creating during activation, and |
| * unattached during disposal. When created, they always have a |
| * strong reference to them via the {@code resources} static member. Explicit |
| * {@code dispose} calls will unregister the native resource and remove |
| * references to the SystemResource object. Absent an explicit dispose, |
| * when their associated Activation object becomes garbage, the SystemResource |
| * object will be enqueued on the reference queue and disposed at the |
| * next call to {@code flush}. |
| */ |
| class SystemResource extends WeakReference<Activation> { |
| |
| private long handle; |
| |
| private static ReferenceQueue<Activation> referenceQueue = |
| referenceQueue = new ReferenceQueue<Activation>(); |
| static HashSet<SystemResource> resources = new HashSet<SystemResource>(); |
| |
| SystemResource(Activation activation, long handle) { |
| super(activation, referenceQueue); |
| this.handle = handle; |
| flush(); |
| resources.add(this); |
| } |
| |
| void dispose() { |
| JVM.dispose(handle); |
| resources.remove(this); |
| handle = 0; |
| } |
| |
| static void flush() { |
| SystemResource resource = null; |
| while ((resource = (SystemResource)referenceQueue.poll()) != null) { |
| if (resource.handle != 0) { |
| resource.dispose(); |
| } |
| } |
| } |
| } |
| |