/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*
*/
package org.apache.mina.filter.codec.textline;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import org.apache.mina.common.AttributeKey;
import org.apache.mina.common.BufferDataException;
import org.apache.mina.common.IoBuffer;
import org.apache.mina.common.IoSession;
import org.apache.mina.filter.codec.ProtocolDecoder;
import org.apache.mina.filter.codec.ProtocolDecoderException;
import org.apache.mina.filter.codec.ProtocolDecoderOutput;
import org.apache.mina.filter.codec.RecoverableProtocolDecoderException;
/**
* A {@link ProtocolDecoder} which decodes a text line into a string.
*
* @author The Apache MINA Project (dev@mina.apache.org)
* @version $Rev: 636237 $, $Date: 2008-03-12 16:35:18 +0900 (수, 12 3월 2008) $,
*/
public class TextLineDecoder implements ProtocolDecoder {
private final AttributeKey CONTEXT = new AttributeKey(getClass(), "context");
private final Charset charset;
private final LineDelimiter delimiter;
private IoBuffer delimBuf;
private int maxLineLength = 1024;
/**
* Creates a new instance with the current default {@link Charset}
* and {@link LineDelimiter#AUTO} delimiter.
*/
public TextLineDecoder() {
this(LineDelimiter.AUTO);
}
/**
* Creates a new instance with the current default {@link Charset}
* and the specified <tt>delimiter</tt>.
*/
public TextLineDecoder(String delimiter) {
this(new LineDelimiter(delimiter));
}
/**
* Creates a new instance with the current default {@link Charset}
* and the specified <tt>delimiter</tt>.
*/
public TextLineDecoder(LineDelimiter delimiter) {
this(Charset.defaultCharset(), delimiter);
}
/**
* Creates a new instance with the spcified <tt>charset</tt>
* and {@link LineDelimiter#AUTO} delimiter.
*/
public TextLineDecoder(Charset charset) {
this(charset, LineDelimiter.AUTO);
}
/**
* Creates a new instance with the spcified <tt>charset</tt>
* and the specified <tt>delimiter</tt>.
*/
public TextLineDecoder(Charset charset, String delimiter) {
this(charset, new LineDelimiter(delimiter));
}
/**
* Creates a new instance with the specified <tt>charset</tt>
* and the specified <tt>delimiter</tt>.
*/
public TextLineDecoder(Charset charset, LineDelimiter delimiter) {
if (charset == null) {
throw new NullPointerException("charset");
}
if (delimiter == null) {
throw new NullPointerException("delimiter");
}
this.charset = charset;
this.delimiter = delimiter;
}
/**
* Returns the allowed maximum size of the line to be decoded.
* If the size of the line to be decoded exceeds this value, the
* decoder will throw a {@link BufferDataException}. The default
* value is <tt>1024</tt> (1KB).
*/
public int getMaxLineLength() {
return maxLineLength;
}
/**
* Sets the allowed maximum size of the line to be decoded.
* If the size of the line to be decoded exceeds this value, the
* decoder will throw a {@link BufferDataException}. The default
* value is <tt>1024</tt> (1KB).
*/
public void setMaxLineLength(int maxLineLength) {
if (maxLineLength <= 0) {
throw new IllegalArgumentException("maxLineLength: "
+ maxLineLength);
}
this.maxLineLength = maxLineLength;
}
public void decode(IoSession session, IoBuffer in,
ProtocolDecoderOutput out) throws Exception {
Context ctx = getContext(session);
if (LineDelimiter.AUTO.equals(delimiter)) {
decodeAuto(ctx, in, out);
} else {
decodeNormal(ctx, in, out);
}
}
private Context getContext(IoSession session) {
Context ctx;
ctx = (Context) session.getAttribute(CONTEXT);
if (ctx == null) {
ctx = new Context();
session.setAttribute(CONTEXT, ctx);
}
return ctx;
}
public void finishDecode(IoSession session, ProtocolDecoderOutput out)
throws Exception {
}
public void dispose(IoSession session) throws Exception {
Context ctx = (Context) session.getAttribute(CONTEXT);
if (ctx != null) {
session.removeAttribute(CONTEXT);
}
}
private void decodeAuto(Context ctx, IoBuffer in, ProtocolDecoderOutput out)
throws CharacterCodingException, ProtocolDecoderException {
int matchCount = ctx.getMatchCount();
// Try to find a match
int oldPos = in.position();
int oldLimit = in.limit();
while (in.hasRemaining()) {
byte b = in.get();
boolean matched = false;
switch (b) {
case '\r':
// Might be Mac, but we don't auto-detect Mac EOL
// to avoid confusion.
matchCount++;
break;
case '\n':
// UNIX
matchCount++;
matched = true;
break;
default:
matchCount = 0;
}
if (matched) {
// Found a match.
int pos = in.position();
in.limit(pos);
in.position(oldPos);
ctx.append(in);
in.limit(oldLimit);
in.position(pos);
if (ctx.getOverflowPosition() == 0) {
IoBuffer buf = ctx.getBuffer();
buf.flip();
buf.limit(buf.limit() - matchCount);
try {
out.write(buf.getString(ctx.getDecoder()));
} finally {
buf.clear();
}
} else {
int overflowPosition = ctx.getOverflowPosition();
ctx.reset();
throw new RecoverableProtocolDecoderException(
"Line is too long: " + overflowPosition);
}
oldPos = pos;
matchCount = 0;
}
}
// Put remainder to buf.
in.position(oldPos);
ctx.append(in);
ctx.setMatchCount(matchCount);
}
private void decodeNormal(Context ctx, IoBuffer in, ProtocolDecoderOutput out)
throws CharacterCodingException, ProtocolDecoderException {
int matchCount = ctx.getMatchCount();
// Convert delimiter to ByteBuffer if not done yet.
if (delimBuf == null) {
IoBuffer tmp = IoBuffer.allocate(2).setAutoExpand(true);
tmp.putString(delimiter.getValue(), charset.newEncoder());
tmp.flip();
delimBuf = tmp;
}
// Try to find a match
int oldPos = in.position();
int oldLimit = in.limit();
while (in.hasRemaining()) {
byte b = in.get();
if (delimBuf.get(matchCount) == b) {
matchCount++;
if (matchCount == delimBuf.limit()) {
// Found a match.
int pos = in.position();
in.limit(pos);
in.position(oldPos);
ctx.append(in);
in.limit(oldLimit);
in.position(pos);
if (ctx.getOverflowPosition() == 0) {
IoBuffer buf = ctx.getBuffer();
buf.flip();
buf.limit(buf.limit() - matchCount);
try {
out.write(buf.getString(ctx.getDecoder()));
} finally {
buf.clear();
}
} else {
int overflowPosition = ctx.getOverflowPosition();
ctx.reset();
throw new RecoverableProtocolDecoderException(
"Line is too long: " + overflowPosition);
}
oldPos = pos;
matchCount = 0;
}
} else {
// fix for DIRMINA-506 & DIRMINA-536
in.position(Math.max(0, in.position() - matchCount));
matchCount = 0;
}
}
// Put remainder to buf.
in.position(oldPos);
ctx.append(in);
ctx.setMatchCount(matchCount);
}
private class Context {
private final CharsetDecoder decoder;
private final IoBuffer buf;
private int matchCount = 0;
private int overflowPosition = 0;
private Context() {
decoder = charset.newDecoder();
buf = IoBuffer.allocate(80).setAutoExpand(true);
}
public CharsetDecoder getDecoder() {
return decoder;
}
public IoBuffer getBuffer() {
return buf;
}
public int getOverflowPosition() {
return overflowPosition;
}
public int getMatchCount() {
return matchCount;
}
public void setMatchCount(int matchCount) {
this.matchCount = matchCount;
}
public void reset() {
overflowPosition = 0;
matchCount = 0;
decoder.reset();
}
public void append(IoBuffer in) {
if (overflowPosition != 0) {
discard(in);
} else if (buf.position() > maxLineLength - in.remaining()) {
overflowPosition = buf.position();
buf.clear();
discard(in);
} else {
getBuffer().put(in);
}
}
private void discard(IoBuffer in) {
if (Integer.MAX_VALUE - in.remaining() < overflowPosition) {
overflowPosition = Integer.MAX_VALUE;
} else {
overflowPosition += in.remaining();
}
in.position(in.limit());
}
}
}