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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.
/* -*- Mode: java; tab-width: 4; indent-tabs-mode: 1; 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.*;
/**
Base class for native object implementation that uses IdFunctionObject to export its methods to script via .prototype object.
Any descendant should implement at least the following methods:
findInstanceIdInfo
getInstanceIdName
execIdCall
methodArity
To define non-function properties, the descendant should override
getInstanceIdValue
setInstanceIdValue
to get/set property value and provide its default attributes.
To customize initialization of constructor and prototype objects, descendant
may override scopeInit or fillConstructorProperties methods.
*/
public abstract class IdScriptableObject extends ScriptableObject
implements IdFunctionCall
{
private transient PrototypeValues prototypeValues;
private static final class PrototypeValues implements Serializable
{
static final long serialVersionUID = 3038645279153854371L;
private static final int NAME_SLOT = 1;
private static final int SLOT_SPAN = 2;
private IdScriptableObject obj;
private int maxId;
private Object[] valueArray;
private short[] attributeArray;
// The following helps to avoid creation of valueArray during runtime
// initialization for common case of "constructor" property
int constructorId;
private IdFunctionObject constructor;
private short constructorAttrs;
PrototypeValues(IdScriptableObject obj, int maxId)
{
if (obj == null) throw new IllegalArgumentException();
if (maxId < 1) throw new IllegalArgumentException();
this.obj = obj;
this.maxId = maxId;
}
final int getMaxId()
{
return maxId;
}
final void initValue(int id, String name, Object value, int attributes)
{
if (!(1 <= id && id <= maxId))
throw new IllegalArgumentException();
if (name == null)
throw new IllegalArgumentException();
if (value == NOT_FOUND)
throw new IllegalArgumentException();
ScriptableObject.checkValidAttributes(attributes);
if (obj.findPrototypeId(name) != id)
throw new IllegalArgumentException(name);
if (id == constructorId) {
if (!(value instanceof IdFunctionObject)) {
throw new IllegalArgumentException("consructor should be initialized with IdFunctionObject");
}
constructor = (IdFunctionObject)value;
constructorAttrs = (short)attributes;
return;
}
initSlot(id, name, value, attributes);
}
private void initSlot(int id, String name, Object value,
int attributes)
{
Object[] array = valueArray;
if (array == null)
throw new IllegalStateException();
if (value == null) {
value = UniqueTag.NULL_VALUE;
}
int index = (id - 1) * SLOT_SPAN;
synchronized (this) {
Object value2 = array[index];
if (value2 == null) {
array[index] = value;
array[index + NAME_SLOT] = name;
attributeArray[id - 1] = (short)attributes;
} else {
if (!name.equals(array[index + NAME_SLOT]))
throw new IllegalStateException();
}
}
}
final IdFunctionObject createPrecachedConstructor()
{
if (constructorId != 0) throw new IllegalStateException();
constructorId = obj.findPrototypeId("constructor");
if (constructorId == 0) {
throw new IllegalStateException(
"No id for constructor property");
}
obj.initPrototypeId(constructorId);
if (constructor == null) {
throw new IllegalStateException(
obj.getClass().getName()+".initPrototypeId() did not "
+"initialize id="+constructorId);
}
constructor.initFunction(obj.getClassName(),
ScriptableObject.getTopLevelScope(obj));
constructor.markAsConstructor(obj);
return constructor;
}
final int findId(String name)
{
return obj.findPrototypeId(name);
}
final boolean has(int id)
{
Object[] array = valueArray;
if (array == null) {
// Not yet initialized, assume all exists
return true;
}
int valueSlot = (id - 1) * SLOT_SPAN;
Object value = array[valueSlot];
if (value == null) {
// The particular entry has not been yet initialized
return true;
}
return value != NOT_FOUND;
}
final Object get(int id)
{
Object value = ensureId(id);
if (value == UniqueTag.NULL_VALUE) {
value = null;
}
return value;
}
final void set(int id, Scriptable start, Object value)
{
if (value == NOT_FOUND) throw new IllegalArgumentException();
ensureId(id);
int attr = attributeArray[id - 1];
if ((attr & READONLY) == 0) {
if (start == obj) {
if (value == null) {
value = UniqueTag.NULL_VALUE;
}
int valueSlot = (id - 1) * SLOT_SPAN;
synchronized (this) {
valueArray[valueSlot] = value;
}
}
else {
int nameSlot = (id - 1) * SLOT_SPAN + NAME_SLOT;
String name = (String)valueArray[nameSlot];
start.put(name, start, value);
}
}
}
final void delete(int id)
{
ensureId(id);
int attr = attributeArray[id - 1];
if ((attr & PERMANENT) == 0) {
int valueSlot = (id - 1) * SLOT_SPAN;
synchronized (this) {
valueArray[valueSlot] = NOT_FOUND;
attributeArray[id - 1] = EMPTY;
}
}
}
final int getAttributes(int id)
{
ensureId(id);
return attributeArray[id - 1];
}
final void setAttributes(int id, int attributes)
{
ScriptableObject.checkValidAttributes(attributes);
ensureId(id);
synchronized (this) {
attributeArray[id - 1] = (short)attributes;
}
}
final Object[] getNames(boolean getAll, Object[] extraEntries)
{
Object[] names = null;
int count = 0;
for (int id = 1; id <= maxId; ++id) {
Object value = ensureId(id);
if (getAll || (attributeArray[id - 1] & DONTENUM) == 0) {
if (value != NOT_FOUND) {
int nameSlot = (id - 1) * SLOT_SPAN + NAME_SLOT;
String name = (String)valueArray[nameSlot];
if (names == null) {
names = new Object[maxId];
}
names[count++] = name;
}
}
}
if (count == 0) {
return extraEntries;
} else if (extraEntries == null || extraEntries.length == 0) {
if (count != names.length) {
Object[] tmp = new Object[count];
System.arraycopy(names, 0, tmp, 0, count);
names = tmp;
}
return names;
} else {
int extra = extraEntries.length;
Object[] tmp = new Object[extra + count];
System.arraycopy(extraEntries, 0, tmp, 0, extra);
System.arraycopy(names, 0, tmp, extra, count);
return tmp;
}
}
private Object ensureId(int id)
{
Object[] array = valueArray;
if (array == null) {
synchronized (this) {
array = valueArray;
if (array == null) {
array = new Object[maxId * SLOT_SPAN];
valueArray = array;
attributeArray = new short[maxId];
}
}
}
int valueSlot = (id - 1) * SLOT_SPAN;
Object value = array[valueSlot];
if (value == null) {
if (id == constructorId) {
initSlot(constructorId, "constructor",
constructor, constructorAttrs);
constructor = null; // no need to refer it any longer
} else {
obj.initPrototypeId(id);
}
value = array[valueSlot];
if (value == null) {
throw new IllegalStateException(
obj.getClass().getName()+".initPrototypeId(int id) "
+"did not initialize id="+id);
}
}
return value;
}
}
public IdScriptableObject()
{
}
public IdScriptableObject(Scriptable scope, Scriptable prototype)
{
super(scope, prototype);
}
protected final boolean defaultHas(String name)
{
return super.has(name, this);
}
protected final Object defaultGet(String name)
{
return super.get(name, this);
}
protected final void defaultPut(String name, Object value)
{
super.put(name, this, value);
}
@Override
public boolean has(String name, Scriptable start)
{
int info = findInstanceIdInfo(name);
if (info != 0) {
int attr = (info >>> 16);
if ((attr & PERMANENT) != 0) {
return true;
}
int id = (info & 0xFFFF);
return NOT_FOUND != getInstanceIdValue(id);
}
if (prototypeValues != null) {
int id = prototypeValues.findId(name);
if (id != 0) {
return prototypeValues.has(id);
}
}
return super.has(name, start);
}
@Override
public Object get(String name, Scriptable start)
{
// Check for slot first for performance. This is a very hot code
// path that should be further optimized.
Object value = super.get(name, start);
if (value != NOT_FOUND) {
return value;
}
int info = findInstanceIdInfo(name);
if (info != 0) {
int id = (info & 0xFFFF);
value = getInstanceIdValue(id);
if (value != NOT_FOUND) return value;
}
if (prototypeValues != null) {
int id = prototypeValues.findId(name);
if (id != 0) {
value = prototypeValues.get(id);
if (value != NOT_FOUND) return value;
}
}
return NOT_FOUND;
}
@Override
public void put(String name, Scriptable start, Object value)
{
int info = findInstanceIdInfo(name);
if (info != 0) {
if (start == this && isSealed()) {
throw Context.reportRuntimeError1("msg.modify.sealed",
name);
}
int attr = (info >>> 16);
if ((attr & READONLY) == 0) {
if (start == this) {
int id = (info & 0xFFFF);
setInstanceIdValue(id, value);
}
else {
start.put(name, start, value);
}
}
return;
}
if (prototypeValues != null) {
int id = prototypeValues.findId(name);
if (id != 0) {
if (start == this && isSealed()) {
throw Context.reportRuntimeError1("msg.modify.sealed",
name);
}
prototypeValues.set(id, start, value);
return;
}
}
super.put(name, start, value);
}
@Override
public void delete(String name)
{
int info = findInstanceIdInfo(name);
if (info != 0) {
// Let the super class to throw exceptions for sealed objects
if (!isSealed()) {
int attr = (info >>> 16);
if ((attr & PERMANENT) == 0) {
int id = (info & 0xFFFF);
setInstanceIdValue(id, NOT_FOUND);
}
return;
}
}
if (prototypeValues != null) {
int id = prototypeValues.findId(name);
if (id != 0) {
if (!isSealed()) {
prototypeValues.delete(id);
}
return;
}
}
super.delete(name);
}
@Override
public int getAttributes(String name)
{
int info = findInstanceIdInfo(name);
if (info != 0) {
int attr = (info >>> 16);
return attr;
}
if (prototypeValues != null) {
int id = prototypeValues.findId(name);
if (id != 0) {
return prototypeValues.getAttributes(id);
}
}
return super.getAttributes(name);
}
@Override
public void setAttributes(String name, int attributes)
{
ScriptableObject.checkValidAttributes(attributes);
int info = findInstanceIdInfo(name);
if (info != 0) {
int id = (info & 0xFFFF);
int currentAttributes = (info >>> 16);
if (attributes != currentAttributes) {
setInstanceIdAttributes(id, attributes);
}
return;
}
if (prototypeValues != null) {
int id = prototypeValues.findId(name);
if (id != 0) {
prototypeValues.setAttributes(id, attributes);
return;
}
}
super.setAttributes(name, attributes);
}
@Override
Object[] getIds(boolean getAll)
{
Object[] result = super.getIds(getAll);
if (prototypeValues != null) {
result = prototypeValues.getNames(getAll, result);
}
int maxInstanceId = getMaxInstanceId();
if (maxInstanceId != 0) {
Object[] ids = null;
int count = 0;
for (int id = maxInstanceId; id != 0; --id) {
String name = getInstanceIdName(id);
int info = findInstanceIdInfo(name);
if (info != 0) {
int attr = (info >>> 16);
if ((attr & PERMANENT) == 0) {
if (NOT_FOUND == getInstanceIdValue(id)) {
continue;
}
}
if (getAll || (attr & DONTENUM) == 0) {
if (count == 0) {
// Need extra room for no more then [1..id] names
ids = new Object[id];
}
ids[count++] = name;
}
}
}
if (count != 0) {
if (result.length == 0 && ids.length == count) {
result = ids;
}
else {
Object[] tmp = new Object[result.length + count];
System.arraycopy(result, 0, tmp, 0, result.length);
System.arraycopy(ids, 0, tmp, result.length, count);
result = tmp;
}
}
}
return result;
}
/**
* Get maximum id findInstanceIdInfo can generate.
*/
protected int getMaxInstanceId()
{
return 0;
}
protected static int instanceIdInfo(int attributes, int id)
{
return (attributes << 16) | id;
}
/**
* Map name to id of instance property.
* Should return 0 if not found or the result of
* {@link #instanceIdInfo(int, int)}.
*/
protected int findInstanceIdInfo(String name)
{
return 0;
}
/** Map id back to property name it defines.
*/
protected String getInstanceIdName(int id)
{
throw new IllegalArgumentException(String.valueOf(id));
}
/** Get id value.
** If id value is constant, descendant can call cacheIdValue to store
** value in the permanent cache.
** Default implementation creates IdFunctionObject instance for given id
** and cache its value
*/
protected Object getInstanceIdValue(int id)
{
throw new IllegalStateException(String.valueOf(id));
}
/**
* Set or delete id value. If value == NOT_FOUND , the implementation
* should make sure that the following getInstanceIdValue return NOT_FOUND.
*/
protected void setInstanceIdValue(int id, Object value)
{
throw new IllegalStateException(String.valueOf(id));
}
/**
* Update the attributes of the given instance property. Classes which
* want to support changing property attributes via Object.defineProperty
* must override this method. The default implementation throws
* InternalError.
* @param id the instance property id
* @param attr the new attribute bitset
*/
protected void setInstanceIdAttributes(int id, int attr) {
throw ScriptRuntime.constructError("InternalError",
"Changing attributes not supported for " + getClassName()
+ " " + getInstanceIdName(id) + " property");
}
/** 'thisObj' will be null if invoked as constructor, in which case
** instance of Scriptable should be returned. */
public Object execIdCall(IdFunctionObject f, Context cx, Scriptable scope,
Scriptable thisObj, Object[] args)
{
throw f.unknown();
}
public final IdFunctionObject exportAsJSClass(int maxPrototypeId,
Scriptable scope,
boolean sealed)
{
// Set scope and prototype unless this is top level scope itself
if (scope != this && scope != null) {
setParentScope(scope);
setPrototype(getObjectPrototype(scope));
}
activatePrototypeMap(maxPrototypeId);
IdFunctionObject ctor = prototypeValues.createPrecachedConstructor();
if (sealed) {
sealObject();
}
fillConstructorProperties(ctor);
if (sealed) {
ctor.sealObject();
}
ctor.exportAsScopeProperty();
return ctor;
}
public final boolean hasPrototypeMap()
{
return prototypeValues != null;
}
public final void activatePrototypeMap(int maxPrototypeId)
{
PrototypeValues values = new PrototypeValues(this, maxPrototypeId);
synchronized (this) {
if (prototypeValues != null)
throw new IllegalStateException();
prototypeValues = values;
}
}
public final void initPrototypeMethod(Object tag, int id, String name,
int arity)
{
Scriptable scope = ScriptableObject.getTopLevelScope(this);
IdFunctionObject f = newIdFunction(tag, id, name, arity, scope);
prototypeValues.initValue(id, name, f, DONTENUM);
}
public final void initPrototypeConstructor(IdFunctionObject f)
{
int id = prototypeValues.constructorId;
if (id == 0)
throw new IllegalStateException();
if (f.methodId() != id)
throw new IllegalArgumentException();
if (isSealed()) { f.sealObject(); }
prototypeValues.initValue(id, "constructor", f, DONTENUM);
}
public final void initPrototypeValue(int id, String name, Object value,
int attributes)
{
prototypeValues.initValue(id, name, value, attributes);
}
protected void initPrototypeId(int id)
{
throw new IllegalStateException(String.valueOf(id));
}
protected int findPrototypeId(String name)
{
throw new IllegalStateException(name);
}
protected void fillConstructorProperties(IdFunctionObject ctor)
{
}
protected void addIdFunctionProperty(Scriptable obj, Object tag, int id,
String name, int arity)
{
Scriptable scope = ScriptableObject.getTopLevelScope(obj);
IdFunctionObject f = newIdFunction(tag, id, name, arity, scope);
f.addAsProperty(obj);
}
/**
* Utility method to construct type error to indicate incompatible call
* when converting script thisObj to a particular type is not possible.
* Possible usage would be to have a private function like realThis:
*
* private static NativeSomething realThis(Scriptable thisObj,
* IdFunctionObject f)
* {
* if (!(thisObj instanceof NativeSomething))
* throw incompatibleCallError(f);
* return (NativeSomething)thisObj;
* }
*
* Note that although such function can be implemented universally via
* java.lang.Class.isInstance(), it would be much more slower.
* @param f function that is attempting to convert 'this'
* object.
* @return Scriptable object suitable for a check by the instanceof
* operator.
* @throws RuntimeException if no more instanceof target can be found
*/
protected static EcmaError incompatibleCallError(IdFunctionObject f)
{
throw ScriptRuntime.typeError1("msg.incompat.call",
f.getFunctionName());
}
private IdFunctionObject newIdFunction(Object tag, int id, String name,
int arity, Scriptable scope)
{
IdFunctionObject f = new IdFunctionObject(this, tag, id, name, arity,
scope);
if (isSealed()) { f.sealObject(); }
return f;
}
@Override
public void defineOwnProperty(Context cx, Object key, ScriptableObject desc) {
if (key instanceof String) {
String name = (String) key;
int info = findInstanceIdInfo(name);
if (info != 0) {
int id = (info & 0xFFFF);
if (isAccessorDescriptor(desc)) {
delete(id); // it will be replaced with a slot
} else {
checkPropertyDefinition(desc);
ScriptableObject current = getOwnPropertyDescriptor(cx, key);
checkPropertyChange(name, current, desc);
int attr = (info >>> 16);
Object value = getProperty(desc, "value");
if (value != NOT_FOUND && (attr & READONLY) == 0) {
Object currentValue = getInstanceIdValue(id);
if (!sameValue(value, currentValue)) {
setInstanceIdValue(id, value);
}
}
setAttributes(name, applyDescriptorToAttributeBitset(attr, desc));
return;
}
}
if (prototypeValues != null) {
int id = prototypeValues.findId(name);
if (id != 0) {
if (isAccessorDescriptor(desc)) {
prototypeValues.delete(id); // it will be replaced with a slot
} else {
checkPropertyDefinition(desc);
ScriptableObject current = getOwnPropertyDescriptor(cx, key);
checkPropertyChange(name, current, desc);
int attr = prototypeValues.getAttributes(id);
Object value = getProperty(desc, "value");
if (value != NOT_FOUND && (attr & READONLY) == 0) {
Object currentValue = prototypeValues.get(id);
if (!sameValue(value, currentValue)) {
prototypeValues.set(id, this, value);
}
}
prototypeValues.setAttributes(id, applyDescriptorToAttributeBitset(attr, desc));
return;
}
}
}
}
super.defineOwnProperty(cx, key, desc);
}
@Override
protected ScriptableObject getOwnPropertyDescriptor(Context cx, Object id) {
ScriptableObject desc = super.getOwnPropertyDescriptor(cx, id);
if (desc == null && id instanceof String) {
desc = getBuiltInDescriptor((String) id);
}
return desc;
}
private ScriptableObject getBuiltInDescriptor(String name) {
Object value = null;
int attr = EMPTY;
Scriptable scope = getParentScope();
if (scope == null) {
scope = this;
}
int info = findInstanceIdInfo(name);
if (info != 0) {
int id = (info & 0xFFFF);
value = getInstanceIdValue(id);
attr = (info >>> 16);
return buildDataDescriptor(scope, value, attr);
}
if (prototypeValues != null) {
int id = prototypeValues.findId(name);
if (id != 0) {
value = prototypeValues.get(id);
attr = prototypeValues.getAttributes(id);
return buildDataDescriptor(scope, value, attr);
}
}
return null;
}
private void readObject(ObjectInputStream stream)
throws IOException, ClassNotFoundException
{
stream.defaultReadObject();
int maxPrototypeId = stream.readInt();
if (maxPrototypeId != 0) {
activatePrototypeMap(maxPrototypeId);
}
}
private void writeObject(ObjectOutputStream stream)
throws IOException
{
stream.defaultWriteObject();
int maxPrototypeId = 0;
if (prototypeValues != null) {
maxPrototypeId = prototypeValues.getMaxId();
}
stream.writeInt(maxPrototypeId);
}
}
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