/*
* ====================================================================
* 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.http.impl.io;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CoderResult;
import org.apache.http.MessageConstraintException;
import org.apache.http.annotation.NotThreadSafe;
import org.apache.http.config.MessageConstraints;
import org.apache.http.io.BufferInfo;
import org.apache.http.io.HttpTransportMetrics;
import org.apache.http.io.SessionInputBuffer;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.Args;
import org.apache.http.util.Asserts;
import org.apache.http.util.ByteArrayBuffer;
import org.apache.http.util.CharArrayBuffer;
/**
* Abstract base class for session input buffers that stream data from
* an arbitrary {@link InputStream}. This class buffers input data in
* an internal byte array for optimal input performance.
* <p/>
* {@link #readLine(CharArrayBuffer)} and {@link #readLine()} methods of this
* class treat a lone LF as valid line delimiters in addition to CR-LF required
* by the HTTP specification.
*
* @since 4.3
*/
@NotThreadSafe
public class SessionInputBufferImpl implements SessionInputBuffer, BufferInfo {
private final HttpTransportMetricsImpl metrics;
private final byte[] buffer;
private final ByteArrayBuffer linebuffer;
private final int minChunkLimit;
private final MessageConstraints constraints;
private final CharsetDecoder decoder;
private InputStream instream;
private int bufferpos;
private int bufferlen;
private CharBuffer cbuf;
/**
* Creates new instance of SessionInputBufferImpl.
*
* @param metrics HTTP transport metrics.
* @param buffersize buffer size. Must be a positive number.
* @param minChunkLimit size limit below which data chunks should be buffered in memory
* in order to minimize native method invocations on the underlying network socket.
* The optimal value of this parameter can be platform specific and defines a trade-off
* between performance of memory copy operations and that of native method invocation.
* If negative default chunk limited will be used.
* @param constraints Message constraints. If <code>null</code>
* {@link MessageConstraints#DEFAULT} will be used.
* @param chardecoder chardecoder to be used for decoding HTTP protocol elements.
* If <code>null</code> simple type cast will be used for byte to char conversion.
*/
public SessionInputBufferImpl(
final HttpTransportMetricsImpl metrics,
int buffersize,
int minChunkLimit,
final MessageConstraints constraints,
final CharsetDecoder chardecoder) {
Args.notNull(metrics, "HTTP transport metrcis");
Args.positive(buffersize, "Buffer size");
this.metrics = metrics;
this.buffer = new byte[buffersize];
this.bufferpos = 0;
this.bufferlen = 0;
this.minChunkLimit = minChunkLimit >= 0 ? minChunkLimit : 512;
this.constraints = constraints != null ? constraints : MessageConstraints.DEFAULT;
this.linebuffer = new ByteArrayBuffer(buffersize);
this.decoder = chardecoder;
}
public void bind(final InputStream instream) {
this.instream = instream;
}
public boolean isBound() {
return this.instream != null;
}
public int capacity() {
return this.buffer.length;
}
public int length() {
return this.bufferlen - this.bufferpos;
}
public int available() {
return capacity() - length();
}
private int streamRead(final byte[] b, int off, int len) throws IOException {
Asserts.notNull(this.instream, "Input stream");
return this.instream.read(b, off, len);
}
public int fillBuffer() throws IOException {
// compact the buffer if necessary
if (this.bufferpos > 0) {
int len = this.bufferlen - this.bufferpos;
if (len > 0) {
System.arraycopy(this.buffer, this.bufferpos, this.buffer, 0, len);
}
this.bufferpos = 0;
this.bufferlen = len;
}
int l;
int off = this.bufferlen;
int len = this.buffer.length - off;
l = streamRead(this.buffer, off, len);
if (l == -1) {
return -1;
} else {
this.bufferlen = off + l;
this.metrics.incrementBytesTransferred(l);
return l;
}
}
public boolean hasBufferedData() {
return this.bufferpos < this.bufferlen;
}
public int read() throws IOException {
int noRead = 0;
while (!hasBufferedData()) {
noRead = fillBuffer();
if (noRead == -1) {
return -1;
}
}
return this.buffer[this.bufferpos++] & 0xff;
}
public int read(final byte[] b, int off, int len) throws IOException {
if (b == null) {
return 0;
}
if (hasBufferedData()) {
int chunk = Math.min(len, this.bufferlen - this.bufferpos);
System.arraycopy(this.buffer, this.bufferpos, b, off, chunk);
this.bufferpos += chunk;
return chunk;
}
// If the remaining capacity is big enough, read directly from the
// underlying input stream bypassing the buffer.
if (len > this.minChunkLimit) {
int read = streamRead(b, off, len);
if (read > 0) {
this.metrics.incrementBytesTransferred(read);
}
return read;
} else {
// otherwise read to the buffer first
while (!hasBufferedData()) {
int noRead = fillBuffer();
if (noRead == -1) {
return -1;
}
}
int chunk = Math.min(len, this.bufferlen - this.bufferpos);
System.arraycopy(this.buffer, this.bufferpos, b, off, chunk);
this.bufferpos += chunk;
return chunk;
}
}
public int read(final byte[] b) throws IOException {
if (b == null) {
return 0;
}
return read(b, 0, b.length);
}
private int locateLF() {
for (int i = this.bufferpos; i < this.bufferlen; i++) {
if (this.buffer[i] == HTTP.LF) {
return i;
}
}
return -1;
}
/**
* Reads a complete line of characters up to a line delimiter from this
* session buffer into the given line buffer. The number of chars actually
* read is returned as an integer. The line delimiter itself is discarded.
* If no char is available because the end of the stream has been reached,
* the value <code>-1</code> is returned. This method blocks until input
* data is available, end of file is detected, or an exception is thrown.
* <p>
* This method treats a lone LF as a valid line delimiters in addition
* to CR-LF required by the HTTP specification.
*
* @param charbuffer the line buffer.
* @return one line of characters
* @exception IOException if an I/O error occurs.
*/
public int readLine(final CharArrayBuffer charbuffer) throws IOException {
Args.notNull(charbuffer, "Char array buffer");
int noRead = 0;
boolean retry = true;
while (retry) {
// attempt to find end of line (LF)
int i = locateLF();
if (i != -1) {
// end of line found.
if (this.linebuffer.isEmpty()) {
// the entire line is preset in the read buffer
return lineFromReadBuffer(charbuffer, i);
}
retry = false;
int len = i + 1 - this.bufferpos;
this.linebuffer.append(this.buffer, this.bufferpos, len);
this.bufferpos = i + 1;
} else {
// end of line not found
if (hasBufferedData()) {
int len = this.bufferlen - this.bufferpos;
this.linebuffer.append(this.buffer, this.bufferpos, len);
this.bufferpos = this.bufferlen;
}
noRead = fillBuffer();
if (noRead == -1) {
retry = false;
}
}
int maxLineLen = this.constraints.getMaxLineLength();
if (maxLineLen > 0 && this.linebuffer.length() >= maxLineLen) {
throw new MessageConstraintException("Maximum line length limit exceeded");
}
}
if (noRead == -1 && this.linebuffer.isEmpty()) {
// indicate the end of stream
return -1;
}
return lineFromLineBuffer(charbuffer);
}
/**
* Reads a complete line of characters up to a line delimiter from this
* session buffer. The line delimiter itself is discarded. If no char is
* available because the end of the stream has been reached,
* <code>null</code> is returned. This method blocks until input data is
* available, end of file is detected, or an exception is thrown.
* <p>
* This method treats a lone LF as a valid line delimiters in addition
* to CR-LF required by the HTTP specification.
*
* @return HTTP line as a string
* @exception IOException if an I/O error occurs.
*/
private int lineFromLineBuffer(final CharArrayBuffer charbuffer)
throws IOException {
// discard LF if found
int len = this.linebuffer.length();
if (len > 0) {
if (this.linebuffer.byteAt(len - 1) == HTTP.LF) {
len--;
}
// discard CR if found
if (len > 0) {
if (this.linebuffer.byteAt(len - 1) == HTTP.CR) {
len--;
}
}
}
if (this.decoder == null) {
charbuffer.append(this.linebuffer, 0, len);
} else {
ByteBuffer bbuf = ByteBuffer.wrap(this.linebuffer.buffer(), 0, len);
len = appendDecoded(charbuffer, bbuf);
}
this.linebuffer.clear();
return len;
}
private int lineFromReadBuffer(final CharArrayBuffer charbuffer, int pos)
throws IOException {
int off = this.bufferpos;
int len;
this.bufferpos = pos + 1;
if (pos > off && this.buffer[pos - 1] == HTTP.CR) {
// skip CR if found
pos--;
}
len = pos - off;
if (this.decoder == null) {
charbuffer.append(this.buffer, off, len);
} else {
ByteBuffer bbuf = ByteBuffer.wrap(this.buffer, off, len);
len = appendDecoded(charbuffer, bbuf);
}
return len;
}
private int appendDecoded(
final CharArrayBuffer charbuffer, final ByteBuffer bbuf) throws IOException {
if (!bbuf.hasRemaining()) {
return 0;
}
if (this.cbuf == null) {
this.cbuf = CharBuffer.allocate(1024);
}
this.decoder.reset();
int len = 0;
while (bbuf.hasRemaining()) {
CoderResult result = this.decoder.decode(bbuf, this.cbuf, true);
len += handleDecodingResult(result, charbuffer, bbuf);
}
CoderResult result = this.decoder.flush(this.cbuf);
len += handleDecodingResult(result, charbuffer, bbuf);
this.cbuf.clear();
return len;
}
private int handleDecodingResult(
final CoderResult result,
final CharArrayBuffer charbuffer,
final ByteBuffer bbuf) throws IOException {
if (result.isError()) {
result.throwException();
}
this.cbuf.flip();
int len = this.cbuf.remaining();
while (this.cbuf.hasRemaining()) {
charbuffer.append(this.cbuf.get());
}
this.cbuf.compact();
return len;
}
public String readLine() throws IOException {
CharArrayBuffer charbuffer = new CharArrayBuffer(64);
int l = readLine(charbuffer);
if (l != -1) {
return charbuffer.toString();
} else {
return null;
}
}
public boolean isDataAvailable(int timeout) throws IOException {
return hasBufferedData();
}
public HttpTransportMetrics getMetrics() {
return this.metrics;
}
}