package fi.iki.elonen;
/*
* ====================================================================
* 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/>.
*
*/
import java.io.IOException;
import java.io.InputStream;
/**
* 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
* {@link #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 enum State
{
CHUNK_LEN, CHUNK_DATA, CHUNK_CRLF, CHUNK_INVALID
}
private static final int BUFFER_SIZE = 2048;
/** The session input buffer */
private final InputStream inputStream;
private State state;
/** The chunk size */
private long chunkSize;
/** The current position within the current chunk */
private long pos;
/** True if we've reached the end of stream */
private boolean eof;
/** True if this stream is closed */
private boolean closed;
/**
* Default constructor.
*
* @param buffer Session input buffer
* @param inputStream Input stream
* @param http1Config Message http1Config. If {@code null} {@link Http1Config#DEFAULT} will be
* used.
*
* @since 4.4
*/
public ChunkedInputStream( final InputStream inputStream )
{
super();
this.inputStream = inputStream;
this.pos = 0L;
this.state = State.CHUNK_LEN;
}
@Override
public int available() throws IOException
{
final int len = this.inputStream.available();
return (int)Math.min( len, this.chunkSize - this.pos );
}
/**
* <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
*/
@Override
public int read() throws IOException
{
if ( this.closed ) {
throw new StreamClosedException( "Already closed" );
}
if ( this.eof ) {
return -1;
}
if ( state != State.CHUNK_DATA ) {
nextChunk();
if ( this.eof ) {
return -1;
}
}
final int b = inputStream.read();
if ( b != -1 ) {
pos++;
if ( pos >= chunkSize ) {
state = State.CHUNK_CRLF;
}
return b;
}
throw new MalformedChunkCodingException( "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.
* @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
*/
@Override
public int read( final byte[] b, final int off, final int len ) throws IOException
{
if ( closed ) {
throw new StreamClosedException( "Already closed" );
}
if ( eof ) {
return -1;
}
if ( state != State.CHUNK_DATA ) {
nextChunk();
if ( eof ) {
return -1;
}
}
int bytesRead = inputStream.read( b, off, (int)Math.min( len, chunkSize - pos ) );
if ( bytesRead != -1 ) {
pos += bytesRead;
if ( pos >= chunkSize ) {
state = State.CHUNK_CRLF;
}
return bytesRead;
}
eof = true;
throw new MalformedChunkCodingException( "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
*/
@Override
public int read( final 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
{
if ( state == State.CHUNK_INVALID ) {
throw new MalformedChunkCodingException( "Corrupt data stream" );
}
try {
chunkSize = getChunkSize();
if ( chunkSize < 0L ) {
throw new MalformedChunkCodingException( "Negative chunk size" );
}
state = State.CHUNK_DATA;
pos = 0L;
if ( chunkSize == 0L ) {
eof = true;
try {
inputStream.read();
inputStream.read();
} catch ( IOException e ) {
throw new MalformedChunkCodingException( "No CRLF after final zero chunk" );
}
}
} catch ( final MalformedChunkCodingException ex ) {
state = State.CHUNK_INVALID;
throw ex;
}
}
/**
* 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.
*/
private long getChunkSize() throws IOException
{
int ch;
int prevCh;
boolean hadSemi;
final State st = this.state;
switch ( st ) {
case CHUNK_CRLF:
ch = inputStream.read();
ch = ( ch << 8 ) | inputStream.read();
if ( ch < 0 ) {
throw new MalformedChunkCodingException(
"CRLF expected at end of chunk" );
}
if ( ch != 3338 ) {
throw new MalformedChunkCodingException(
"Unexpected content at the end of chunk" );
}
state = State.CHUNK_LEN;
//$FALL-THROUGH$
case CHUNK_LEN:
prevCh = -1;
hadSemi = false;
StringBuilder sb = new StringBuilder( 8 );
for ( ;; ) {
ch = inputStream.read();
if ( ch == -1 )
break;
if ( prevCh == 13 && ch == 10 ) {
break;
}
prevCh = ch;
if ( ch == 13 )
continue;
if ( ch == ';' ) {
hadSemi = true;
}
if ( hadSemi )
continue;
sb.append( (char)ch );
}
if ( prevCh != 13 || ch != 10 ) {
throw new StreamClosedException( "Premature end of chunk coded message body" );
}
final String s = sb.toString();
try {
return Long.parseLong( s, 16 );
} catch ( final NumberFormatException e ) {
throw new MalformedChunkCodingException( "Invalid hex-length in chunk header: " + s );
}
default:
throw new IllegalStateException( "Inconsistent codec state" );
}
}
/**
* Reads the remainder of the chunked message, leaving the underlying
* stream at a position to start reading the next response without
* scanning. But does NOT close the underlying stream.
*
* @throws IOException in case of an I/O error
*/
@Override
public void close() throws IOException
{
if ( !closed ) {
try {
if ( !eof && state != State.CHUNK_INVALID ) {
// Optimistically check if the content has been fully read
// when there's no data remaining in the current chunk.
// This is common when self-terminating content (e.g. JSON)
// is parsed from response streams.
if ( chunkSize == pos && chunkSize > 0 && read() == -1 ) {
return;
}
// read and discard the remainder of the message
final byte[] buff = new byte[ BUFFER_SIZE ];
while ( read( buff ) >= 0 ) {
}
}
} finally {
eof = true;
closed = true;
}
}
}
public static class MalformedChunkCodingException extends IOException
{
private static final long serialVersionUID = 7092137465179737109L;
public MalformedChunkCodingException( String msg )
{
super( msg );
}
}
public static class StreamClosedException extends IOException
{
private static final long serialVersionUID = -5871567871867283867L;
public StreamClosedException( String msg )
{
super( msg );
}
}
}
