com.oracle.truffle.object.TransitionMap Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of truffle-api Show documentation
Show all versions of truffle-api Show documentation
Truffle is a multi-language framework for executing dynamic languages
that achieves high performance when combined with Graal.
/*
* Copyright (c) 2019, 2023, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* The Universal Permissive License (UPL), Version 1.0
*
* Subject to the condition set forth below, permission is hereby granted to any
* person obtaining a copy of this software, associated documentation and/or
* data (collectively the "Software"), free of charge and under any and all
* copyright rights in the Software, and any and all patent rights owned or
* freely licensable by each licensor hereunder covering either (i) the
* unmodified Software as contributed to or provided by such licensor, or (ii)
* the Larger Works (as defined below), to deal in both
*
* (a) the Software, and
*
* (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
* one is included with the Software each a "Larger Work" to which the Software
* is contributed by such licensors),
*
* without restriction, including without limitation the rights to copy, create
* derivative works of, display, perform, and distribute the Software and make,
* use, sell, offer for sale, import, export, have made, and have sold the
* Software and the Larger Work(s), and to sublicense the foregoing rights on
* either these or other terms.
*
* This license is subject to the following condition:
*
* The above copyright notice and either this complete permission notice or at a
* minimum a reference to the UPL must be included in all copies or substantial
* portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
package com.oracle.truffle.object;
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
import java.util.Objects;
import java.util.function.BiConsumer;
import java.util.function.BiFunction;
import org.graalvm.collections.EconomicMap;
import org.graalvm.collections.Equivalence;
import org.graalvm.collections.MapCursor;
/**
* A synchronized hash map with weakly referenced values. Cleared value references are expunged only
* when the map is mutated. Keys may be strongly or weakly referenced.
*/
final class TransitionMap {
/** Key is either {@code K} or {@code WeakKey}. */
private final EconomicMap> map;
private final ReferenceQueue queue;
private static final Equivalence WEAK_KEY_EQUIVALENCE = new WeakKeyEquivalence();
TransitionMap() {
this.map = EconomicMap.create(WEAK_KEY_EQUIVALENCE);
this.queue = new ReferenceQueue<>();
}
public boolean containsKey(Object key) {
return get(key) != null;
}
private V getValue(StrongKeyWeakValueEntry entry) {
return entry == null ? null : entry.get();
}
@SuppressWarnings("unchecked")
public V get(Object key) {
synchronized (queue) {
return getValue(map.get(key));
}
}
private V putAnyKey(Object key, V value) {
synchronized (queue) {
expungeStaleEntries();
return getValue(map.put(key, new StrongKeyWeakValueEntry<>(key, value, queue)));
}
}
private V putAnyKeyIfAbsent(Object key, V value) {
synchronized (queue) {
expungeStaleEntries();
return getValue(map.putIfAbsent(key, new StrongKeyWeakValueEntry<>(key, value, queue)));
}
}
/**
* Insert with strongly referenced key.
*/
public V put(K key, V value) {
return putAnyKey(key, value);
}
/**
* Insert with strongly referenced key, if absent.
*/
public V putIfAbsent(K key, V value) {
return putAnyKeyIfAbsent(key, value);
}
/**
* Insert with weakly referenced key.
*/
public V putWeakKey(K key, V value) {
ShapeImpl.shapeCacheWeakKeys.inc();
WeakKey weakKey = new WeakKey<>(key);
return putAnyKey(weakKey, value);
}
/**
* Insert with weakly referenced key, if absent.
*/
public V putWeakKeyIfAbsent(K key, V value) {
ShapeImpl.shapeCacheWeakKeys.inc();
WeakKey weakKey = new WeakKey<>(key);
return putAnyKeyIfAbsent(weakKey, value);
}
public V remove(Object key) {
synchronized (queue) {
expungeStaleEntries();
return getValue(map.removeKey(key));
}
}
private void expungeStaleEntries() {
for (Reference r; (r = queue.poll()) != null;) {
if (r instanceof StrongKeyWeakValueEntry) {
StrongKeyWeakValueEntry entry = (StrongKeyWeakValueEntry) r;
if (map.get(entry.getKey()) == entry) {
map.removeKey(entry.getKey());
ShapeImpl.shapeCacheExpunged.inc();
}
}
}
}
public void clear() {
synchronized (queue) {
while (queue.poll() != null) {
// clear out ref queue.
}
map.clear();
}
}
public void forEach(BiConsumer consumer) {
synchronized (queue) {
MapCursor> cursor = map.getEntries();
while (cursor.advance()) {
V value = cursor.getValue().get();
if (value != null) {
K key = unwrapKey(cursor.getKey());
if (key != null) {
consumer.accept(key, value);
}
}
}
}
}
public R iterateEntries(BiFunction consumer) {
synchronized (queue) {
MapCursor> cursor = map.getEntries();
while (cursor.advance()) {
V value = cursor.getValue().get();
if (value != null) {
K key = unwrapKey(cursor.getKey());
if (key != null) {
R result = consumer.apply(key, value);
if (result != null) {
return result;
}
}
}
}
}
return null;
}
@SuppressWarnings("unchecked")
private K unwrapKey(Object key) {
if (key instanceof WeakKey) {
return ((WeakKey) key).get();
}
return (K) key;
}
private static final class WeakKeyEquivalence extends Equivalence {
@Override
public int hashCode(Object o) {
return o.hashCode();
}
@Override
public boolean equals(Object a, Object b) {
boolean aIsWeak = a instanceof WeakKey;
boolean bIsWeak = b instanceof WeakKey;
if (aIsWeak && !bIsWeak) {
return Objects.equals(((WeakKey) a).get(), b);
} else if (!aIsWeak && bIsWeak) {
return Objects.equals(a, ((WeakKey) b).get());
}
return a.equals(b);
}
}
}