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/*
This file is part of GNUnet.
Copyright (C) 2011, 2012 Christian Grothoff (and other contributing authors)
GNUnet is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published
by the Free Software Foundation; either version 3, or (at your
option) any later version.
GNUnet 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 for more details.
You should have received a copy of the GNU General Public License
along with GNUnet; see the file COPYING. If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
package org.gnunet.construct.parsers;
import org.gnunet.construct.*;
import java.lang.reflect.Field;
import java.nio.ByteBuffer;
import java.util.List;
// unchecked casts are necessary
@SuppressWarnings("unchecked")
public class UnionParser implements Parser {
private final Field targetField;
private final List<Field> unionTagPath;
private final ReflectUtil.NumField unionTagField;
private final Class<? extends MessageUnion> unionType;
boolean optional;
public UnionParser(boolean optional, Class<? extends MessageUnion> unionType,
List<Field> unionTagPath, Field f) {
targetField = f;
this.optional = optional;
this.unionTagPath = unionTagPath;
this.unionTagField = new ReflectUtil.NumField(unionTagPath.get(unionTagPath.size() - 1));
this.unionType = unionType;
}
@Override
public int getSize(final Message src) {
Object target = ReflectUtil.justGet(src, targetField);
if (target == null) {
if (optional) {
return 0;
} else {
throw new AssertionError("non-optional union member must not be null");
}
}
Class cls = ReflectUtil.justGet(src, targetField).getClass();
Parser parser = Construct.getParser(cls);
return parser.getSize((Message)ReflectUtil.justGet(src, targetField));
}
@Override
public int parse(final ByteBuffer srcBuf, int frameOffset, Message frameObj, final Message dstObj, List<Field>
frameSizePath) {
if (optional) {
if (frameSizePath == null) {
throw new AssertionError("missing @FrameSize");
}
int remaining = frameOffset + ReflectUtil.justGetInt(frameObj, frameSizePath) - srcBuf.position();
if (remaining <= 0) {
if (!optional) {
throw new ProtocolViolationException("not optional");
}
ReflectUtil.justSet(dstObj, targetField, null);
return 0;
}
}
long unionTag = unionTagField.get(ReflectUtil.followFieldPathToParent(unionTagPath, dstObj));
final Class cls;
cls = MessageLoader.getUnionClass(unionType, (int) unionTag);
ReflectUtil.justSet(dstObj, targetField, ReflectUtil.justInstantiate(cls));
final Message theUnion = (Message) ReflectUtil.justGet(dstObj, targetField);
Parser parser = Construct.getParser(cls);
return parser.parse(srcBuf, frameOffset, frameObj, theUnion, frameSizePath);
}
@Override
public int write(final ByteBuffer dstBuf, final Message src) {
final Object target = ReflectUtil.justGet(src, targetField);
if (target == null) {
if (optional) {
return 0;
} else {
throw new AssertionError("non-optional union member must not be null");
}
}
final Class currentUnionClass = target.getClass();
final Parser p = Construct.getParser(currentUnionClass);
return p.write(dstBuf, (Message) ReflectUtil.justGet(src, targetField));
}
@SuppressWarnings("unchecked")
public int getTag(Message m) {
return MessageLoader.getUnionTag(unionType, (Class<MessageUnion>) ReflectUtil.justGet(m, targetField).getClass());
}
@Override
public void patch(Message m, int frameSize, List<Field> frameSizePath, Message frameObj) {
final Class currentUnionClass = ReflectUtil.justGet(m, targetField).getClass();
final Parser p = Construct.getParser(currentUnionClass);
p.patch((Message) ReflectUtil.justGet(m, targetField), frameSize, frameSizePath, frameObj);
unionTagField.set(ReflectUtil.followFieldPathToParent(unionTagPath, m),
getTag(m));
}
@Override
public int getStaticSize() {
// we can't say anything about the static size
// todo: in a more elaborate implementation, try all union members
return 0;
}
}
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