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Rhino JavaScript runtime jar, excludes tools & JSR-223 Script Engine wrapper.
/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.javascript;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.util.WeakHashMap;
/**
* This is an implementation of the ES6 WeakSet class. It is very similar to NativeWeakMap, with the
* exception being that it doesn't store any values. Java will GC the key only when there is no
* longer any reference to it other than the weak reference. That means that it is important that
* the "value" that we put in the WeakHashMap here is not one that contains the key.
*/
public class NativeWeakSet extends IdScriptableObject {
private static final long serialVersionUID = 2065753364224029534L;
private static final Object MAP_TAG = "WeakSet";
private boolean instanceOfWeakSet = false;
private transient WeakHashMap map = new WeakHashMap<>();
static void init(Scriptable scope, boolean sealed) {
NativeWeakSet m = new NativeWeakSet();
m.exportAsJSClass(MAX_PROTOTYPE_ID, scope, sealed);
}
@Override
public String getClassName() {
return "WeakSet";
}
@Override
public Object execIdCall(
IdFunctionObject f, Context cx, Scriptable scope, Scriptable thisObj, Object[] args) {
if (!f.hasTag(MAP_TAG)) {
return super.execIdCall(f, cx, scope, thisObj, args);
}
int id = f.methodId();
switch (id) {
case Id_constructor:
if (thisObj == null) {
NativeWeakSet ns = new NativeWeakSet();
ns.instanceOfWeakSet = true;
if (args.length > 0) {
NativeSet.loadFromIterable(cx, scope, ns, NativeMap.key(args));
}
return ns;
}
throw ScriptRuntime.typeErrorById("msg.no.new", "WeakSet");
case Id_add:
return realThis(thisObj, f).js_add(NativeMap.key(args));
case Id_delete:
return realThis(thisObj, f).js_delete(NativeMap.key(args));
case Id_has:
return realThis(thisObj, f).js_has(NativeMap.key(args));
}
throw new IllegalArgumentException(
"WeakMap.prototype has no method: " + f.getFunctionName());
}
private Object js_add(Object key) {
// As the spec says, only a true "Object" can be the key to a WeakSet.
// Use the default object equality here. ScriptableObject does not override
// equals or hashCode, which means that in effect we are only keying on object identity.
// This is all correct according to the ECMAscript spec.
if (!ScriptRuntime.isObject(key)) {
throw ScriptRuntime.typeErrorById("msg.arg.not.object", ScriptRuntime.typeof(key));
}
// Add a value to the map, but don't make it the key -- otherwise the WeakHashMap
// will never GC anything.
map.put((Scriptable) key, Boolean.TRUE);
return this;
}
private Object js_delete(Object key) {
if (!ScriptRuntime.isObject(key)) {
return Boolean.FALSE;
}
return Boolean.valueOf(map.remove(key) != null);
}
private Object js_has(Object key) {
if (!ScriptRuntime.isObject(key)) {
return Boolean.FALSE;
}
return Boolean.valueOf(map.containsKey(key));
}
private static NativeWeakSet realThis(Scriptable thisObj, IdFunctionObject f) {
final NativeWeakSet ns = ensureType(thisObj, NativeWeakSet.class, f);
if (!ns.instanceOfWeakSet) {
// Check for "Set internal data tag"
throw ScriptRuntime.typeErrorById("msg.incompat.call", f.getFunctionName());
}
return ns;
}
@Override
protected void initPrototypeId(int id) {
if (id == SymbolId_toStringTag) {
initPrototypeValue(
SymbolId_toStringTag,
SymbolKey.TO_STRING_TAG,
getClassName(),
DONTENUM | READONLY);
return;
}
String s, fnName = null;
int arity;
switch (id) {
case Id_constructor:
arity = 0;
s = "constructor";
break;
case Id_add:
arity = 1;
s = "add";
break;
case Id_delete:
arity = 1;
s = "delete";
break;
case Id_has:
arity = 1;
s = "has";
break;
default:
throw new IllegalArgumentException(String.valueOf(id));
}
initPrototypeMethod(MAP_TAG, id, s, fnName, arity);
}
@Override
protected int findPrototypeId(Symbol k) {
if (SymbolKey.TO_STRING_TAG.equals(k)) {
return SymbolId_toStringTag;
}
return 0;
}
@Override
protected int findPrototypeId(String s) {
int id;
switch (s) {
case "constructor":
id = Id_constructor;
break;
case "add":
id = Id_add;
break;
case "delete":
id = Id_delete;
break;
case "has":
id = Id_has;
break;
default:
id = 0;
break;
}
return id;
}
private static final int Id_constructor = 1,
Id_add = 2,
Id_delete = 3,
Id_has = 4,
SymbolId_toStringTag = 5,
MAX_PROTOTYPE_ID = SymbolId_toStringTag;
private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
stream.defaultReadObject();
map = new WeakHashMap<>();
}
}