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Rhino is an open-source implementation of JavaScript written entirely in
Java. It is typically embedded into Java applications to provide
scripting to end users.
The newest version!
/* -*- 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;
/**
* This class implements the "arguments" object.
*
* See ECMA 10.1.8
*
* @see org.mozilla.javascript.NativeCall
* @author Norris Boyd
*/
final class Arguments extends IdScriptableObject
{
static final long serialVersionUID = 4275508002492040609L;
private static final String FTAG = "Arguments";
public Arguments(NativeCall activation)
{
this.activation = activation;
Scriptable parent = activation.getParentScope();
setParentScope(parent);
setPrototype(ScriptableObject.getObjectPrototype(parent));
args = activation.originalArgs;
lengthObj = Integer.valueOf(args.length);
NativeFunction f = activation.function;
calleeObj = f;
Scriptable topLevel = getTopLevelScope(parent);
constructor = getProperty(topLevel, "Object");
int version = f.getLanguageVersion();
if (version <= Context.VERSION_1_3
&& version != Context.VERSION_DEFAULT)
{
callerObj = null;
} else {
callerObj = NOT_FOUND;
}
}
@Override
public String getClassName()
{
return FTAG;
}
private Object arg(int index) {
if (index < 0 || args.length <= index) return NOT_FOUND;
return args[index];
}
// the following helper methods assume that 0 < index < args.length
private void putIntoActivation(int index, Object value) {
String argName = activation.function.getParamOrVarName(index);
activation.put(argName, activation, value);
}
private Object getFromActivation(int index) {
String argName = activation.function.getParamOrVarName(index);
return activation.get(argName, activation);
}
private void replaceArg(int index, Object value) {
if (sharedWithActivation(index)) {
putIntoActivation(index, value);
}
synchronized (this) {
if (args == activation.originalArgs) {
args = args.clone();
}
args[index] = value;
}
}
private void removeArg(int index) {
synchronized (this) {
if (args[index] != NOT_FOUND) {
if (args == activation.originalArgs) {
args = args.clone();
}
args[index] = NOT_FOUND;
}
}
}
// end helpers
@Override
public boolean has(int index, Scriptable start)
{
if (arg(index) != NOT_FOUND) {
return true;
}
return super.has(index, start);
}
@Override
public Object get(int index, Scriptable start)
{
final Object value = arg(index);
if (value == NOT_FOUND) {
return super.get(index, start);
} else {
if (sharedWithActivation(index)) {
return getFromActivation(index);
} else {
return value;
}
}
}
private boolean sharedWithActivation(int index)
{
NativeFunction f = activation.function;
int definedCount = f.getParamCount();
if (index < definedCount) {
// Check if argument is not hidden by later argument with the same
// name as hidden arguments are not shared with activation
if (index < definedCount - 1) {
String argName = f.getParamOrVarName(index);
for (int i = index + 1; i < definedCount; i++) {
if (argName.equals(f.getParamOrVarName(i))) {
return false;
}
}
}
return true;
}
return false;
}
@Override
public void put(int index, Scriptable start, Object value)
{
if (arg(index) == NOT_FOUND) {
super.put(index, start, value);
} else {
replaceArg(index, value);
}
}
@Override
public void delete(int index)
{
if (0 <= index && index < args.length) {
removeArg(index);
}
super.delete(index);
}
// #string_id_map#
private static final int
Id_callee = 1,
Id_length = 2,
Id_caller = 3,
Id_constructor = 4,
MAX_INSTANCE_ID = Id_constructor;
@Override
protected int getMaxInstanceId()
{
return MAX_INSTANCE_ID;
}
@Override
protected int findInstanceIdInfo(String s)
{
int id;
// #generated# Last update: 2010-01-06 05:48:21 ARST
L0: { id = 0; String X = null; int c;
int s_length = s.length();
if (s_length==6) {
c=s.charAt(5);
if (c=='e') { X="callee";id=Id_callee; }
else if (c=='h') { X="length";id=Id_length; }
else if (c=='r') { X="caller";id=Id_caller; }
}
else if (s_length==11) { X="constructor";id=Id_constructor; }
if (X!=null && X!=s && !X.equals(s)) id = 0;
break L0;
}
// #/generated#
if (id == 0) return super.findInstanceIdInfo(s);
int attr;
switch (id) {
case Id_callee:
case Id_caller:
case Id_length:
case Id_constructor:
attr = DONTENUM;
break;
default: throw new IllegalStateException();
}
return instanceIdInfo(attr, id);
}
// #/string_id_map#
@Override
protected String getInstanceIdName(int id)
{
switch (id) {
case Id_callee: return "callee";
case Id_length: return "length";
case Id_caller: return "caller";
case Id_constructor: return "constructor";
}
return null;
}
@Override
protected Object getInstanceIdValue(int id)
{
switch (id) {
case Id_callee: return calleeObj;
case Id_length: return lengthObj;
case Id_caller: {
Object value = callerObj;
if (value == UniqueTag.NULL_VALUE) { value = null; }
else if (value == null) {
NativeCall caller = activation.parentActivationCall;
if (caller != null) {
value = caller.get("arguments", caller);
}
}
return value;
}
case Id_constructor:
return constructor;
}
return super.getInstanceIdValue(id);
}
@Override
protected void setInstanceIdValue(int id, Object value)
{
switch (id) {
case Id_callee: calleeObj = value; return;
case Id_length: lengthObj = value; return;
case Id_caller:
callerObj = (value != null) ? value : UniqueTag.NULL_VALUE;
return;
case Id_constructor: constructor = value; return;
}
super.setInstanceIdValue(id, value);
}
@Override
Object[] getIds(boolean getAll)
{
Object[] ids = super.getIds(getAll);
if (args.length != 0) {
boolean[] present = new boolean[args.length];
int extraCount = args.length;
for (int i = 0; i != ids.length; ++i) {
Object id = ids[i];
if (id instanceof Integer) {
int index = ((Integer)id).intValue();
if (0 <= index && index < args.length) {
if (!present[index]) {
present[index] = true;
extraCount--;
}
}
}
}
if (!getAll) { // avoid adding args which were redefined to non-enumerable
for (int i = 0; i < present.length; i++) {
if (!present[i] && super.has(i, this)) {
present[i] = true;
extraCount--;
}
}
}
if (extraCount != 0) {
Object[] tmp = new Object[extraCount + ids.length];
System.arraycopy(ids, 0, tmp, extraCount, ids.length);
ids = tmp;
int offset = 0;
for (int i = 0; i != args.length; ++i) {
if (present == null || !present[i]) {
ids[offset] = Integer.valueOf(i);
++offset;
}
}
if (offset != extraCount) Kit.codeBug();
}
}
return ids;
}
@Override
protected ScriptableObject getOwnPropertyDescriptor(Context cx, Object id) {
double d = ScriptRuntime.toNumber(id);
int index = (int) d;
if (d != index) {
return super.getOwnPropertyDescriptor(cx, id);
}
Object value = arg(index);
if (value == NOT_FOUND) {
return super.getOwnPropertyDescriptor(cx, id);
}
if (sharedWithActivation(index)) {
value = getFromActivation(index);
}
if (super.has(index, this)) { // the descriptor has been redefined
ScriptableObject desc = super.getOwnPropertyDescriptor(cx, id);
desc.put("value", desc, value);
return desc;
} else {
Scriptable scope = getParentScope();
if (scope == null) scope = this;
return buildDataDescriptor(scope, value, EMPTY);
}
}
@Override
protected void defineOwnProperty(Context cx, Object id,
ScriptableObject desc,
boolean checkValid) {
super.defineOwnProperty(cx, id, desc, checkValid);
double d = ScriptRuntime.toNumber(id);
int index = (int) d;
if (d != index) return;
Object value = arg(index);
if (value == NOT_FOUND) return;
if (isAccessorDescriptor(desc)) {
removeArg(index);
return;
}
Object newValue = getProperty(desc, "value");
if (newValue == NOT_FOUND) return;
replaceArg(index, newValue);
if (isFalse(getProperty(desc, "writable"))) {
removeArg(index);
}
}
// Fields to hold caller, callee and length properties,
// where NOT_FOUND value tags deleted properties.
// In addition if callerObj == NULL_VALUE, it tags null for scripts, as
// initial callerObj == null means access to caller arguments available
// only in JS <= 1.3 scripts
private Object callerObj;
private Object calleeObj;
private Object lengthObj;
private Object constructor;
private NativeCall activation;
// Initially args holds activation.getOriginalArgs(), but any modification
// of its elements triggers creation of a copy. If its element holds NOT_FOUND,
// it indicates deleted index, in which case super class is queried.
private Object[] args;
}