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Nashorn is an Open Source JavaScript (ECMAScript 5.1 and some 6 features) engine for the JVM.
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/*
* Copyright (c) 2016, 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 org.openjdk.nashorn.internal.objects;
import java.util.Map;
import java.util.WeakHashMap;
import org.openjdk.nashorn.internal.objects.annotations.Attribute;
import org.openjdk.nashorn.internal.objects.annotations.Constructor;
import org.openjdk.nashorn.internal.objects.annotations.Function;
import org.openjdk.nashorn.internal.objects.annotations.ScriptClass;
import org.openjdk.nashorn.internal.runtime.PropertyMap;
import org.openjdk.nashorn.internal.runtime.ScriptObject;
import org.openjdk.nashorn.internal.runtime.ScriptRuntime;
import org.openjdk.nashorn.internal.runtime.Undefined;
import static org.openjdk.nashorn.internal.runtime.ECMAErrors.typeError;
import static org.openjdk.nashorn.internal.runtime.JSType.isPrimitive;
/**
* This implements the ECMA6 WeakMap object.
*/
@ScriptClass("WeakMap")
public class NativeWeakMap extends ScriptObject {
private final Map jmap = new WeakHashMap<>();
// initialized by nasgen
private static PropertyMap $nasgenmap$;
private NativeWeakMap(final ScriptObject proto, final PropertyMap map) {
super(proto, map);
}
/**
* ECMA6 23.3.1 The WeakMap Constructor
*
* @param isNew whether the new operator used
* @param self self reference
* @param arg optional iterable argument
* @return a new WeakMap object
*/
@Constructor(arity = 0)
public static Object construct(final boolean isNew, final Object self, final Object arg) {
if (!isNew) {
throw typeError("constructor.requires.new", "WeakMap");
}
final Global global = Global.instance();
final NativeWeakMap weakMap = new NativeWeakMap(global.getWeakMapPrototype(), $nasgenmap$);
populateMap(weakMap.jmap, arg, global);
return weakMap;
}
/**
* ECMA6 23.3.3.5 WeakMap.prototype.set ( key , value )
*
* @param self the self reference
* @param key the key
* @param value the value
* @return this WeakMap object
*/
@Function(attributes = Attribute.NOT_ENUMERABLE)
public static Object set(final Object self, final Object key, final Object value) {
final NativeWeakMap map = getMap(self);
map.jmap.put(checkKey(key), value);
return self;
}
/**
* ECMA6 23.3.3.3 WeakMap.prototype.get ( key )
*
* @param self the self reference
* @param key the key
* @return the associated value or undefined
*/
@Function(attributes = Attribute.NOT_ENUMERABLE)
public static Object get(final Object self, final Object key) {
final NativeWeakMap map = getMap(self);
if (isPrimitive(key)) {
return Undefined.getUndefined();
}
return map.jmap.get(key);
}
/**
* ECMA6 23.3.3.2 WeakMap.prototype.delete ( key )
*
* @param self the self reference
* @param key the key to delete
* @return true if the key was deleted
*/
@Function(attributes = Attribute.NOT_ENUMERABLE)
public static boolean delete(final Object self, final Object key) {
final Map map = getMap(self).jmap;
if (isPrimitive(key)) {
return false;
}
final boolean returnValue = map.containsKey(key);
map.remove(key);
return returnValue;
}
/**
* ECMA6 23.3.3.4 WeakMap.prototype.has ( key )
*
* @param self the self reference
* @param key the key
* @return true if key is contained
*/
@Function(attributes = Attribute.NOT_ENUMERABLE)
public static boolean has(final Object self, final Object key) {
final NativeWeakMap map = getMap(self);
return !isPrimitive(key) && map.jmap.containsKey(key);
}
@Override
public String getClassName() {
return "WeakMap";
}
/**
* Make sure {@code key} is not a JavaScript primitive value.
*
* @param key a key object
* @return the valid key
*/
static Object checkKey(final Object key) {
if (isPrimitive(key)) {
throw typeError("invalid.weak.key", ScriptRuntime.safeToString(key));
}
return key;
}
static void populateMap(final Map map, final Object arg, final Global global) {
// This method is similar to NativeMap.populateMap, but it uses a different
// map implementation and the checking/conversion of keys differs as well.
if (arg != null && arg != Undefined.getUndefined()) {
AbstractIterator.iterate(arg, global, value -> {
if (isPrimitive(value)) {
throw typeError(global, "not.an.object", ScriptRuntime.safeToString(value));
}
if (value instanceof ScriptObject) {
final ScriptObject sobj = (ScriptObject) value;
map.put(checkKey(sobj.get(0)), sobj.get(1));
}
});
}
}
private static NativeWeakMap getMap(final Object self) {
if (self instanceof NativeWeakMap) {
return (NativeWeakMap)self;
} else {
throw typeError("not.a.weak.map", ScriptRuntime.safeToString(self));
}
}
}