/* -*- 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.serialize;
import java.util.Map;
import java.util.HashMap;
import java.util.StringTokenizer;
import java.io.*;
import org.mozilla.javascript.*;
/**
* Class ScriptableOutputStream is an ObjectOutputStream used
* to serialize JavaScript objects and functions. Note that
* compiled functions currently cannot be serialized, only
* interpreted functions. The top-level scope containing the
* object is not written out, but is instead replaced with
* another top-level object when the ScriptableInputStream
* reads in this object. Also, object corresponding to names
* added to the exclude list are not written out but instead
* are looked up during deserialization. This approach avoids
* the creation of duplicate copies of standard objects
* during deserialization.
*
* @author Norris Boyd
*/
// API class
public class ScriptableOutputStream extends ObjectOutputStream {
/**
* ScriptableOutputStream constructor.
* Creates a ScriptableOutputStream for use in serializing
* JavaScript objects. Calls excludeStandardObjectNames.
*
* @param out the OutputStream to write to.
* @param scope the scope containing the object.
*/
public ScriptableOutputStream(OutputStream out, Scriptable scope)
throws IOException
{
super(out);
this.scope = scope;
table = new HashMap<Object,String>();
table.put(scope, "");
enableReplaceObject(true);
excludeStandardObjectNames(); // XXX
}
public void excludeAllIds(Object[] ids) {
for (Object id: ids) {
if (id instanceof String &&
(scope.get((String) id, scope) instanceof Scriptable))
{
this.addExcludedName((String)id);
}
}
}
/**
* Adds a qualified name to the list of object to be excluded from
* serialization. Names excluded from serialization are looked up
* in the new scope and replaced upon deserialization.
* @param name a fully qualified name (of the form "a.b.c", where
* "a" must be a property of the top-level object). The object
* need not exist, in which case the name is ignored.
* @throws IllegalArgumentException if the object is not a
* {@link Scriptable}.
*/
public void addOptionalExcludedName(String name) {
Object obj = lookupQualifiedName(scope, name);
if(obj != null && obj != UniqueTag.NOT_FOUND) {
if (!(obj instanceof Scriptable)) {
throw new IllegalArgumentException(
"Object for excluded name " + name +
" is not a Scriptable, it is " +
obj.getClass().getName());
}
table.put(obj, name);
}
}
/**
* Adds a qualified name to the list of objects to be excluded from
* serialization. Names excluded from serialization are looked up
* in the new scope and replaced upon deserialization.
* @param name a fully qualified name (of the form "a.b.c", where
* "a" must be a property of the top-level object)
* @throws IllegalArgumentException if the object is not found or is not
* a {@link Scriptable}.
*/
public void addExcludedName(String name) {
Object obj = lookupQualifiedName(scope, name);
if (!(obj instanceof Scriptable)) {
throw new IllegalArgumentException("Object for excluded name " +
name + " not found.");
}
table.put(obj, name);
}
/**
* Returns true if the name is excluded from serialization.
*/
public boolean hasExcludedName(String name) {
return table.get(name) != null;
}
/**
* Removes a name from the list of names to exclude.
*/
public void removeExcludedName(String name) {
table.remove(name);
}
/**
* Adds the names of the standard objects and their
* prototypes to the list of excluded names.
*/
public void excludeStandardObjectNames() {
String[] names = { "Object", "Object.prototype",
"Function", "Function.prototype",
"String", "String.prototype",
"Math", // no Math.prototype
"Array", "Array.prototype",
"Error", "Error.prototype",
"Number", "Number.prototype",
"Date", "Date.prototype",
"RegExp", "RegExp.prototype",
"Script", "Script.prototype",
"Continuation", "Continuation.prototype",
};
for (int i=0; i < names.length; i++) {
addExcludedName(names[i]);
}
String[] optionalNames = {
"XML", "XML.prototype",
"XMLList", "XMLList.prototype",
};
for (int i=0; i < optionalNames.length; i++) {
addOptionalExcludedName(optionalNames[i]);
}
}
static Object lookupQualifiedName(Scriptable scope,
String qualifiedName)
{
StringTokenizer st = new StringTokenizer(qualifiedName, ".");
Object result = scope;
while (st.hasMoreTokens()) {
String s = st.nextToken();
result = ScriptableObject.getProperty((Scriptable)result, s);
if (result == null || !(result instanceof Scriptable))
break;
}
return result;
}
static class PendingLookup implements Serializable
{
static final long serialVersionUID = -2692990309789917727L;
PendingLookup(String name) { this.name = name; }
String getName() { return name; }
private String name;
}
@Override
protected Object replaceObject(Object obj) throws IOException
{
if (false) throw new IOException(); // suppress warning
String name = table.get(obj);
if (name == null)
return obj;
return new PendingLookup(name);
}
private Scriptable scope;
private Map<Object,String> table;
}