/*
* ====================================================================
* 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apache.ogt.http.impl.io;
import java.io.IOException;
import java.io.InputStream;
import org.apache.ogt.http.Header;
import org.apache.ogt.http.HttpException;
import org.apache.ogt.http.MalformedChunkCodingException;
import org.apache.ogt.http.TruncatedChunkException;
import org.apache.ogt.http.io.BufferInfo;
import org.apache.ogt.http.io.SessionInputBuffer;
import org.apache.ogt.http.util.CharArrayBuffer;
import org.apache.ogt.http.util.ExceptionUtils;
/**
* Implements chunked transfer coding. The content is received in small chunks.
* Entities transferred using this input stream can be of unlimited length.
* After the stream is read to the end, it provides access to the trailers,
* if any.
* <p>
* Note that this class NEVER closes the underlying stream, even when close
* gets called. Instead, it will read until the "end" of its chunking on
* close, which allows for the seamless execution of subsequent HTTP 1.1
* requests, while not requiring the client to remember to read the entire
* contents of the response.
*
*
* @since 4.0
*
*/
public class ChunkedInputStream extends InputStream {
private static final int CHUNK_LEN = 1;
private static final int CHUNK_DATA = 2;
private static final int CHUNK_CRLF = 3;
private static final int BUFFER_SIZE = 2048;
/** The session input buffer */
private final SessionInputBuffer in;
private final CharArrayBuffer buffer;
private int state;
/** The chunk size */
private int chunkSize;
/** The current position within the current chunk */
private int pos;
/** True if we've reached the end of stream */
private boolean eof = false;
/** True if this stream is closed */
private boolean closed = false;
private Header[] footers = new Header[] {};
/**
* Wraps session input stream and reads chunk coded input.
*
* @param in The session input buffer
*/
public ChunkedInputStream(final SessionInputBuffer in) {
super();
if (in == null) {
throw new IllegalArgumentException("Session input buffer may not be null");
}
this.in = in;
this.pos = 0;
this.buffer = new CharArrayBuffer(16);
this.state = CHUNK_LEN;
}
public int available() throws IOException {
if (this.in instanceof BufferInfo) {
int len = ((BufferInfo) this.in).length();
return Math.min(len, this.chunkSize - this.pos);
} else {
return 0;
}
}
/**
* <p> Returns all the data in a chunked stream in coalesced form. A chunk
* is followed by a CRLF. The method returns -1 as soon as a chunksize of 0
* is detected.</p>
*
* <p> Trailer headers are read automatically at the end of the stream and
* can be obtained with the getResponseFooters() method.</p>
*
* @return -1 of the end of the stream has been reached or the next data
* byte
* @throws IOException in case of an I/O error
*/
public int read() throws IOException {
if (this.closed) {
throw new IOException("Attempted read from closed stream.");
}
if (this.eof) {
return -1;
}
if (state != CHUNK_DATA) {
nextChunk();
if (this.eof) {
return -1;
}
}
int b = in.read();
if (b != -1) {
pos++;
if (pos >= chunkSize) {
state = CHUNK_CRLF;
}
}
return b;
}
/**
* Read some bytes from the stream.
* @param b The byte array that will hold the contents from the stream.
* @param off The offset into the byte array at which bytes will start to be
* placed.
* @param len the maximum number of bytes that can be returned.
* @return The number of bytes returned or -1 if the end of stream has been
* reached.
* @throws IOException in case of an I/O error
*/
public int read (byte[] b, int off, int len) throws IOException {
if (closed) {
throw new IOException("Attempted read from closed stream.");
}
if (eof) {
return -1;
}
if (state != CHUNK_DATA) {
nextChunk();
if (eof) {
return -1;
}
}
len = Math.min(len, chunkSize - pos);
int bytesRead = in.read(b, off, len);
if (bytesRead != -1) {
pos += bytesRead;
if (pos >= chunkSize) {
state = CHUNK_CRLF;
}
return bytesRead;
} else {
eof = true;
throw new TruncatedChunkException("Truncated chunk "
+ "( expected size: " + chunkSize
+ "; actual size: " + pos + ")");
}
}
/**
* Read some bytes from the stream.
* @param b The byte array that will hold the contents from the stream.
* @return The number of bytes returned or -1 if the end of stream has been
* reached.
* @throws IOException in case of an I/O error
*/
public int read (byte[] b) throws IOException {
return read(b, 0, b.length);
}
/**
* Read the next chunk.
* @throws IOException in case of an I/O error
*/
private void nextChunk() throws IOException {
chunkSize = getChunkSize();
if (chunkSize < 0) {
throw new MalformedChunkCodingException("Negative chunk size");
}
state = CHUNK_DATA;
pos = 0;
if (chunkSize == 0) {
eof = true;
parseTrailerHeaders();
}
}
/**
* Expects the stream to start with a chunksize in hex with optional
* comments after a semicolon. The line must end with a CRLF: "a3; some
* comment\r\n" Positions the stream at the start of the next line.
*
* @param in The new input stream.
* @param required <tt>true<tt/> if a valid chunk must be present,
* <tt>false<tt/> otherwise.
*
* @return the chunk size as integer
*
* @throws IOException when the chunk size could not be parsed
*/
private int getChunkSize() throws IOException {
int st = this.state;
switch (st) {
case CHUNK_CRLF:
this.buffer.clear();
int i = this.in.readLine(this.buffer);
if (i == -1) {
return 0;
}
if (!this.buffer.isEmpty()) {
throw new MalformedChunkCodingException(
"Unexpected content at the end of chunk");
}
state = CHUNK_LEN;
//$FALL-THROUGH$
case CHUNK_LEN:
this.buffer.clear();
i = this.in.readLine(this.buffer);
if (i == -1) {
return 0;
}
int separator = this.buffer.indexOf(';');
if (separator < 0) {
separator = this.buffer.length();
}
try {
return Integer.parseInt(this.buffer.substringTrimmed(0, separator), 16);
} catch (NumberFormatException e) {
throw new MalformedChunkCodingException("Bad chunk header");
}
default:
throw new IllegalStateException("Inconsistent codec state");
}
}
/**
* Reads and stores the Trailer headers.
* @throws IOException in case of an I/O error
*/
private void parseTrailerHeaders() throws IOException {
try {
this.footers = AbstractMessageParser.parseHeaders
(in, -1, -1, null);
} catch (HttpException e) {
IOException ioe = new MalformedChunkCodingException("Invalid footer: "
+ e.getMessage());
ExceptionUtils.initCause(ioe, e);
throw ioe;
}
}
/**
* Upon close, this reads the remainder of the chunked message,
* leaving the underlying socket at a position to start reading the
* next response without scanning.
* @throws IOException in case of an I/O error
*/
public void close() throws IOException {
if (!closed) {
try {
if (!eof) {
// read and discard the remainder of the message
byte buffer[] = new byte[BUFFER_SIZE];
while (read(buffer) >= 0) {
}
}
} finally {
eof = true;
closed = true;
}
}
}
public Header[] getFooters() {
return (Header[])this.footers.clone();
}
}