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/*
 * ====================================================================
 * Licensed to the Apache Software Foundation (ASF) under one
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 * 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.
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 * This software consists of voluntary contributions made by many
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package org.apache.http.impl.io;

import java.io.IOException;
import java.io.InputStream;

import org.apache.http.ConnectionClosedException;
import org.apache.http.Header;
import org.apache.http.HttpException;
import org.apache.http.MalformedChunkCodingException;
import org.apache.http.TruncatedChunkException;
import org.apache.http.config.MessageConstraints;
import org.apache.http.io.BufferInfo;
import org.apache.http.io.SessionInputBuffer;
import org.apache.http.util.Args;
import org.apache.http.util.CharArrayBuffer;

/**
 * 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.
 * 

* 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 CHUNK_INVALID = Integer.MAX_VALUE; private static final int BUFFER_SIZE = 2048; /** The session input buffer */ private final SessionInputBuffer in; private final CharArrayBuffer buffer; private final MessageConstraints constraints; private int 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 = 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 * @param constraints Message constraints. If {@code null} * {@link MessageConstraints#DEFAULT} will be used. * * @since 4.4 */ public ChunkedInputStream(final SessionInputBuffer in, final MessageConstraints constraints) { super(); this.in = Args.notNull(in, "Session input buffer"); this.pos = 0L; this.buffer = new CharArrayBuffer(16); this.constraints = constraints != null ? constraints : MessageConstraints.DEFAULT; this.state = CHUNK_LEN; } /** * Wraps session input stream and reads chunk coded input. * * @param in The session input buffer */ public ChunkedInputStream(final SessionInputBuffer in) { this(in, null); } @Override public int available() throws IOException { if (this.in instanceof BufferInfo) { final int len = ((BufferInfo) this.in).length(); return (int) Math.min(len, this.chunkSize - this.pos); } return 0; } /** *

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.

* *

Trailer headers are read automatically at the end of the stream and * can be obtained with the getResponseFooters() method.

* * @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 IOException("Attempted read from closed stream."); } if (this.eof) { return -1; } if (state != CHUNK_DATA) { nextChunk(); if (this.eof) { return -1; } } final 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 */ @Override public int read (final byte[] b, final int off, final 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; } } final int readLen = in.read(b, off, (int) Math.min(len, chunkSize - pos)); if (readLen != -1) { pos += readLen; if (pos >= chunkSize) { state = CHUNK_CRLF; } return readLen; } eof = true; throw new TruncatedChunkException("Truncated chunk (expected size: %,d; actual size: %,d)", chunkSize, 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 == CHUNK_INVALID) { throw new MalformedChunkCodingException("Corrupt data stream"); } try { chunkSize = getChunkSize(); if (chunkSize < 0L) { throw new MalformedChunkCodingException("Negative chunk size"); } state = CHUNK_DATA; pos = 0L; if (chunkSize == 0L) { eof = true; parseTrailerHeaders(); } } catch (final MalformedChunkCodingException ex) { 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 { final int st = this.state; switch (st) { case CHUNK_CRLF: this.buffer.clear(); final int bytesRead1 = this.in.readLine(this.buffer); if (bytesRead1 == -1) { throw new MalformedChunkCodingException( "CRLF expected at end of chunk"); } 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(); final int bytesRead2 = this.in.readLine(this.buffer); if (bytesRead2 == -1) { throw new ConnectionClosedException( "Premature end of chunk coded message body: closing chunk expected"); } int separator = this.buffer.indexOf(';'); if (separator < 0) { separator = this.buffer.length(); } final String s = this.buffer.substringTrimmed(0, separator); try { return Long.parseLong(s, 16); } catch (final NumberFormatException e) { throw new MalformedChunkCodingException("Bad chunk header: " + s); } 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, constraints.getMaxHeaderCount(), constraints.getMaxLineLength(), null); } catch (final HttpException ex) { final IOException ioe = new MalformedChunkCodingException("Invalid footer: " + ex.getMessage()); ioe.initCause(ex); 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 */ @Override public void close() throws IOException { if (!closed) { try { if (!eof && state != CHUNK_INVALID) { // 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 Header[] getFooters() { return this.footers.clone(); } }




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