[armedbear-cvs] r13250 - in trunk/abcl/src/org/armedbear/lisp: . util
Erik Huelsmann
ehuelsmann at common-lisp.net
Sun Mar 13 19:55:54 UTC 2011
Author: ehuelsmann
Date: Sun Mar 13 15:55:52 2011
New Revision: 13250
Log:
Close #138 by implementing a general post-finalization notification mechanism.
Added:
trunk/abcl/src/org/armedbear/lisp/util/Finalizer.java
Modified:
trunk/abcl/src/org/armedbear/lisp/Autoload.java
trunk/abcl/src/org/armedbear/lisp/Primitives.java
Modified: trunk/abcl/src/org/armedbear/lisp/Autoload.java
==============================================================================
--- trunk/abcl/src/org/armedbear/lisp/Autoload.java (original)
+++ trunk/abcl/src/org/armedbear/lisp/Autoload.java Sun Mar 13 15:55:52 2011
@@ -519,6 +519,8 @@
autoload(PACKAGE_EXT, "string-position", "StringFunctions");
autoload(PACKAGE_EXT, "make-weak-reference", "WeakReference", true);
autoload(PACKAGE_EXT, "weak-reference-value", "WeakReference", true);
+ autoload(PACKAGE_EXT, "finalize", "Primitives", true);
+ autoload(PACKAGE_EXT, "cancel-finalization", "Primitives", true);
autoload(PACKAGE_JAVA, "%jnew-proxy", "JProxy");
autoload(PACKAGE_JAVA, "%find-java-class", "JavaObject");
autoload(PACKAGE_JAVA, "%register-java-class", "JavaObject");
Modified: trunk/abcl/src/org/armedbear/lisp/Primitives.java
==============================================================================
--- trunk/abcl/src/org/armedbear/lisp/Primitives.java (original)
+++ trunk/abcl/src/org/armedbear/lisp/Primitives.java Sun Mar 13 15:55:52 2011
@@ -2,6 +2,7 @@
* Primitives.java
*
* Copyright (C) 2002-2007 Peter Graves
+ * Copyright (C) 2011 Erik Huelsmann
* $Id$
*
* This program is free software; you can redistribute it and/or
@@ -37,6 +38,7 @@
import java.math.BigInteger;
import java.util.ArrayList;
+import org.armedbear.lisp.util.Finalizer;
public final class Primitives {
// ### *
@@ -5818,4 +5820,39 @@
}
};
+ // ### finalize
+ private static final Primitive FINALIZE
+ = new pf_finalize();
+ private static final class pf_finalize extends Primitive {
+ pf_finalize() {
+ super("finalize", PACKAGE_EXT, true, "object function");
+ }
+
+ @Override
+ public LispObject execute(LispObject obj, final LispObject fun) {
+ Finalizer.addFinalizer(obj, new Runnable() {
+ @Override
+ public void run() {
+ fun.execute();
+ }
+ });
+ return obj;
+ }
+ };
+
+ // ### cancel-finalization
+ private static final Primitive CANCEL_FINALIZATION
+ = new pf_cancel_finalization();
+ private static final class pf_cancel_finalization extends Primitive {
+ pf_cancel_finalization() {
+ super("cancel-finalization", PACKAGE_EXT, true, "object");
+ }
+
+ @Override
+ public LispObject execute(LispObject obj) {
+ Finalizer.clearFinalizers(obj);
+ return obj;
+ }
+ };
+
}
Added: trunk/abcl/src/org/armedbear/lisp/util/Finalizer.java
==============================================================================
--- (empty file)
+++ trunk/abcl/src/org/armedbear/lisp/util/Finalizer.java Sun Mar 13 15:55:52 2011
@@ -0,0 +1,172 @@
+/*
+ * Finalizer.java
+ *
+ * Copyright (C) 2010 Mark Evenson
+ * $Id: HttpHead.java 12656 2010-05-06 20:15:26Z mevenson $
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program 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 for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * As a special exception, the copyright holders of this library give you
+ * permission to link this library with independent modules to produce an
+ * executable, regardless of the license terms of these independent
+ * modules, and to copy and distribute the resulting executable under
+ * terms of your choice, provided that you also meet, for each linked
+ * independent module, the terms and conditions of the license of that
+ * module. An independent module is a module which is not derived from
+ * or based on this library. If you modify this library, you may extend
+ * this exception to your version of the library, but you are not
+ * obligated to do so. If you do not wish to do so, delete this
+ * exception statement from your version.
+ */
+package org.armedbear.lisp.util;
+
+import java.lang.ref.ReferenceQueue;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.Map;
+import java.util.WeakHashMap;
+
+/** Framework to monitor arbitrary objects to see if they have been
+ * garbage collected, running one or more runnables when they have.
+ */
+public class Finalizer {
+
+ /** Internal weak reference class which keeps a list of Runnables
+ * with finalizing actions to be executed.
+ */
+ private static class FinalizingWeakReference
+ extends java.lang.ref.WeakReference<Object> {
+
+ /** Queue of Runnables to be executed after the object is GC-ed. */
+ private LinkedList<Runnable> finalizers = new LinkedList<Runnable>();
+
+ FinalizingWeakReference(Object o, ReferenceQueue q, Runnable finalizer) {
+ super(o, q);
+ finalizers.add(finalizer);
+ }
+
+ /** Adds a finalizer.
+ *
+ * Finalizers will be run in reverse-registration order.
+ *
+ * @param finalizer The finalizer to be added.
+ */
+ void addFinalizer(Runnable finalizer) {
+ finalizers.add(finalizer);
+ }
+
+ /** Removes all registered finalizers. */
+ void cancelFinalizers() {
+ finalizers.clear();
+ }
+
+ /** Runs all finalizers registered. */
+ void run() {
+ Iterator<Runnable> iterator = finalizers.iterator();
+ while (iterator.hasNext()) {
+ iterator.next().run();
+ }
+ }
+ }
+
+ /** Queue for FinalizingWeakReference objects which need
+ * to have their references run because the associated
+ * object has been garbage collected
+ */
+ private static ReferenceQueue queue = null;
+
+ /** A map from objects to their associated FinalizingWeakReferences
+ * which is used by the routine which cancels finalization.
+ */
+ private static Map<Object, FinalizingWeakReference> references = null;
+
+ /** A map which maps the finalizing references onto themselves. This map
+ * makes sure that hard (as opposed to weak) references stay around to
+ * prevent garbage collection of the FinalizingWeakReferences before the
+ * referred objects are.
+ */
+ private static Map<FinalizingWeakReference, FinalizingWeakReference> anchor = null;
+
+ /** Checks that the internal administration variables and thread have been
+ * correctly set up. This solution allows the GC monitoring thread to be
+ * started as late as its first use.
+ */
+ synchronized private static void checkQueue() {
+ if (queue == null) {
+ queue = new ReferenceQueue();
+ references = Collections.synchronizedMap(new WeakHashMap<Object, FinalizingWeakReference>());
+ anchor = Collections.synchronizedMap(new HashMap<FinalizingWeakReference, FinalizingWeakReference>());
+
+ Thread handler =
+ new Thread(new Runnable() {
+
+ public void run() {
+ while (true) {
+ try {
+ FinalizingWeakReference ref =
+ (FinalizingWeakReference) queue.remove();
+ anchor.remove(ref);
+ ref.run();
+ } catch (InterruptedException i) {
+ }
+ }
+ }
+ }, "ABCL finalizer");
+
+ handler.setPriority(Thread.MAX_PRIORITY);
+ handler.setDaemon(true);
+ handler.start();
+ }
+ }
+
+ /** Schedules a Runnable to be run after garbage collection of the object.
+ *
+ * Note that the Runnable can't contain references to the object to be
+ * collected: it will disable garbage collection of the object.
+ *
+ * @param o The object to monitor for garbage collection
+ * @param r The routine to be executed after GC-ing the object
+ */
+ public static void addFinalizer(Object o, Runnable r) {
+ if (queue == null) {
+ checkQueue();
+ }
+
+ FinalizingWeakReference ref = references.get(o);
+ if (ref != null) {
+ ref.addFinalizer(r);
+ } else {
+ ref = new FinalizingWeakReference(o, queue, r);
+ references.put(o, ref);
+ anchor.put(ref, ref);
+ }
+ }
+
+ /** Cancels any references scheduled to be run after garbage
+ * collection of the argument 'o'.
+ *
+ * @param o Object to cancel references for
+ */
+ public static void clearFinalizers(Object o) {
+ FinalizingWeakReference ref = references.get(o);
+
+ if (ref != null) {
+ ref.cancelFinalizers();
+ anchor.remove(ref);
+ }
+ }
+}
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