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/***** BEGIN LICENSE BLOCK *****
* Version: EPL 2.0/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Eclipse Public
* License Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.eclipse.org/legal/epl-v20.html
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* Copyright (C) 2002-2004 Jan Arne Petersen <jpetersen@uni-bonn.de>
* Copyright (C) 2002-2004 Anders Bengtsson <ndrsbngtssn@yahoo.se>
* Copyright (C) 2004-2006 Charles O Nutter <headius@headius.com>
* Copyright (C) 2004 Stefan Matthias Aust <sma@3plus4.de>
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the EPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the EPL, the GPL or the LGPL.
***** END LICENSE BLOCK *****/
package org.jruby.runtime;
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
import java.lang.ref.WeakReference;
import java.util.AbstractList;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.atomic.AtomicReferenceArray;
import org.jruby.RubyBasicObject;
import org.jruby.RubyModule;
import org.jruby.java.proxies.JavaProxy;
import org.jruby.javasupport.JavaPackage;
import org.jruby.runtime.builtin.IRubyObject;
import org.jruby.util.WeakIdentityHashMap;
/**
* FIXME: This version is faster than the previous, but both suffer from a
* crucial flaw: It is impossible to create an ObjectSpace with an iterator
* that doesn't either: a. hold on to objects that might otherwise be collected
* or b. have no way to guarantee that a call to hasNext() will be correct or
* that a subsequent call to next() will produce an object. For our purposes,
* for now, this may be acceptable.
*/
public class ObjectSpace {
private final ReferenceQueue<Object> deadReferences = new ReferenceQueue<>();
private final ReferenceQueue<ObjectGroup> objectGroupReferenceQueue = new ReferenceQueue<>();
private WeakReferenceListNode top;
private final ReferenceQueue deadIdentityReferences = new ReferenceQueue();
private final Map<Long, IdReference> identities = new HashMap<>(64);
private final Map<IRubyObject, Long> identitiesByObject = new WeakIdentityHashMap(64);
private static final AtomicLong maxId = new AtomicLong(1000);
private final ThreadLocal<Reference<ObjectGroup>> currentObjectGroup = new ThreadLocal<>();
private Reference<GroupSweeper> groupSweeperReference;
public void registerObjectId(long id, IRubyObject object) {
synchronized (identities) {
cleanIdentities();
identities.put(id, new IdReference(object, id, deadIdentityReferences));
identitiesByObject.put(object, id);
}
}
public static long calculateObjectId(Object object) {
// Fixnums get all the 0b01 id's, flonums get the 0b10 id's, so we use next ID * 4
return maxId.getAndIncrement() * 4;
}
public long createAndRegisterObjectId(IRubyObject rubyObject) {
synchronized (identities) {
Long longId = identitiesByObject.get(rubyObject);
if (longId == null) {
longId = createId(rubyObject);
}
return longId.longValue();
}
}
private long createId(IRubyObject object) {
long id = calculateObjectId(object);
registerObjectId(id, object);
return id;
}
public IRubyObject id2ref(long id) {
synchronized (identities) {
cleanIdentities();
IdReference reference = identities.get(id);
if (reference == null) {
return null;
}
return reference.get();
}
}
private void cleanIdentities() {
IdReference ref;
while ((ref = (IdReference) deadIdentityReferences.poll()) != null) {
identities.remove(ref.id);
}
}
@Deprecated(since = "9.4.10.0")
public void addFinalizer(IRubyObject object, IRubyObject proc) {
addFinalizer(((RubyBasicObject) object).getCurrentContext(), object, proc);
}
public IRubyObject addFinalizer(ThreadContext context, IRubyObject object, IRubyObject proc) {
return object.addFinalizer(context, proc);
}
public void removeFinalizers(long id) {
IRubyObject object = id2ref(id);
if (object != null) {
object.removeFinalizers();
}
}
public void add(IRubyObject object) {
if (object instanceof JavaPackage)
return;
if (true && object.getMetaClass() != null && !(object instanceof JavaProxy)) {
// If the object is already frozen when we encounter it, it's pre-frozen.
// Since this only (currently) applies to objects created outside the
// normal routes of construction, we don't show it in ObjectSpace.
if (object.isFrozen()) return;
getObjectGroup().add(object);
} else {
addIndividualWeakReference(object);
}
}
private synchronized void addIndividualWeakReference(IRubyObject object) {
cleanup(deadReferences);
top = new WeakReferenceListNode<Object>(object, deadReferences, top);
}
private synchronized void registerGroupSweeper() {
if (groupSweeperReference == null || groupSweeperReference.get() == null) {
groupSweeperReference = new WeakReference<GroupSweeper>(new GroupSweeper());
}
}
private synchronized void splitObjectGroups() {
cleanup(objectGroupReferenceQueue);
// Split apart each group into individual weak references
WeakReferenceListNode node = top;
while (node != null) {
Object obj = node.get();
if (obj instanceof ObjectGroup) {
ObjectGroup objectGroup = (ObjectGroup) obj;
for (int i = 0; i < objectGroup.size(); i++) {
IRubyObject rubyObject = objectGroup.set(i, null);
if (rubyObject != null) {
top = new WeakReferenceListNode<Object>(rubyObject, deadReferences, top);
}
}
}
node = node.nextNode;
}
}
public synchronized Iterator iterator(RubyModule rubyClass) {
final ArrayList<Reference<Object>> objList = new ArrayList<>(64);
WeakReferenceListNode current = top;
while (current != null) {
Object obj = current.get();
if (obj instanceof IRubyObject) {
IRubyObject rubyObject = (IRubyObject) obj;
if (rubyClass.isInstance(rubyObject)) {
objList.add(current);
}
} else if (obj instanceof ObjectGroup) {
for (IRubyObject rubyObject : (ObjectGroup) obj) {
if (rubyObject != null && rubyClass.isInstance(rubyObject)) {
objList.add(new WeakReference<Object>(rubyObject));
}
}
}
current = current.nextNode;
}
return new Iterator() {
final Iterator<Reference<Object>> iter = objList.iterator();
public boolean hasNext() {
throw new UnsupportedOperationException();
}
public Object next() {
Object obj = null;
while (iter.hasNext()) {
obj = iter.next().get();
if (obj != null) break;
}
return obj;
}
public void remove() {
throw new UnsupportedOperationException();
}
};
}
private void cleanup(ReferenceQueue<?> referenceQueue) {
WeakReferenceListNode reference;
while ((reference = (WeakReferenceListNode) referenceQueue.poll()) != null) {
reference.remove();
}
}
private class WeakReferenceListNode<T> extends WeakReference<T> {
private WeakReferenceListNode prevNode;
private WeakReferenceListNode nextNode;
public WeakReferenceListNode(T referent, ReferenceQueue<T> queue, WeakReferenceListNode<?> next) {
super(referent, queue);
this.nextNode = next;
if (next != null) {
next.prevNode = this;
}
}
private void remove() {
if (prevNode != null) {
prevNode.nextNode = nextNode;
} else {
top = nextNode;
}
if (nextNode != null) {
nextNode.prevNode = prevNode;
}
}
}
private static class IdReference extends WeakReference<IRubyObject> {
final long id;
IdReference(IRubyObject object, long id, ReferenceQueue queue) {
super(object, queue);
this.id = id;
}
}
private ObjectGroup getObjectGroup() {
Reference<ObjectGroup> ref = currentObjectGroup.get();
ObjectGroup objectGroup = ref != null ? ref.get() : null;
return objectGroup != null && !objectGroup.isFull() ? objectGroup : addObjectGroup();
}
private synchronized ObjectGroup addObjectGroup() {
cleanup(objectGroupReferenceQueue);
ObjectGroup objectGroup;
WeakReferenceListNode<ObjectGroup> ref = new WeakReferenceListNode<ObjectGroup>(objectGroup = new ObjectGroup(),
objectGroupReferenceQueue, top);
currentObjectGroup.set(ref);
top = ref;
if (groupSweeperReference == null) registerGroupSweeper();
return objectGroup;
}
private static final class ObjectGroup extends AbstractList<IRubyObject> {
private static final int MAX_OBJECTS_PER_GROUP = 64;
private final AtomicReferenceArray<IRubyObject> objects = new AtomicReferenceArray<IRubyObject>(MAX_OBJECTS_PER_GROUP);
private int nextIndex = 0;
public boolean add(IRubyObject obj) {
obj.getMetaClass().getObjectGroupAccessorForWrite().set(obj, this);
objects.set(nextIndex, obj);
++nextIndex;
return true;
}
@Override
public IRubyObject get(int index) {
return objects.get(index);
}
@Override
public IRubyObject set(int index, IRubyObject element) {
return objects.getAndSet(index, element);
}
private boolean isFull() {
return nextIndex >= objects.length();
}
public int size() {
return objects.length();
}
}
// This class is used as a low-memory cleaner. When it is finalized, it will cause all groups to be split into
// individual weak refs, so each object can be collected.
private final class GroupSweeper {
@Override
protected void finalize() throws Throwable {
try {
splitObjectGroups();
} finally {
registerGroupSweeper();
super.finalize();
}
}
}
}