io.undertow.protocols.http2.Http2PushBackParser Maven / Gradle / Ivy
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* Copyright 2014 Red Hat, Inc., and individual contributors
* as indicated by the @author tags.
*
* Licensed 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 io.undertow.protocols.http2;
import java.io.IOException;
import java.nio.ByteBuffer;
import io.undertow.UndertowMessages;
/**
* Parser that supports push back when not all data can be read.
*
* @author Stuart Douglas
*/
public abstract class Http2PushBackParser {
private byte[] pushedBackData;
private boolean finished;
private int remainingData;
private final int frameLength;
int cnt;
public Http2PushBackParser(int frameLength) {
this.remainingData = frameLength;
this.frameLength = frameLength;
}
public void parse(ByteBuffer data, Http2FrameHeaderParser headerParser) throws IOException {
int used = 0;
ByteBuffer dataToParse = data;
int oldLimit = data.limit();
try {
if (pushedBackData != null) {
int toCopy = Math.min(remainingData - pushedBackData.length, data.remaining());
dataToParse = ByteBuffer.wrap(new byte[pushedBackData.length + toCopy]);
dataToParse.put(pushedBackData);
data.limit(data.position() + toCopy);
dataToParse.put(data);
dataToParse.flip();
}
if (dataToParse.remaining() > remainingData) {
dataToParse.limit(dataToParse.position() + remainingData);
}
int rem = dataToParse.remaining();
handleData(dataToParse, headerParser);
used = rem - dataToParse.remaining();
if(!isFinished() && remainingData > 0 && used == 0 && dataToParse.remaining() >= remainingData) {
if(cnt++ == 100) {
throw UndertowMessages.MESSAGES.parserDidNotMakeProgress();
}
}
} finally {
//it is possible that we finished the parsing without using up all the data
//and the rest is to be consumed by the stream itself
if (finished) {
data.limit(oldLimit);
return;
}
int leftOver = dataToParse.remaining();
if (leftOver > 0) {
pushedBackData = new byte[leftOver];
dataToParse.get(pushedBackData);
} else {
pushedBackData = null;
}
data.limit(oldLimit);
remainingData -= used;
if (remainingData == 0) {
finished = true;
}
}
}
protected abstract void handleData(ByteBuffer resource, Http2FrameHeaderParser headerParser) throws IOException;
public boolean isFinished() {
if(pushedBackData != null && remainingData == pushedBackData.length) {
return true;
}
return finished;
}
protected void finish() {
finished = true;
}
protected void moreData(int data) {
finished = false;
this.remainingData += data;
}
public int getFrameLength() {
return frameLength;
}
}