/*
* $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/tags/4.0/module-main/src/main/java/org/apache/http/impl/io/AbstractSessionInputBuffer.java $
* $Revision: 744526 $
* $Date: 2009-02-14 18:04:18 +0100 (Sat, 14 Feb 2009) $
*
* ====================================================================
* 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 org.apache.http.io.SessionInputBuffer;
import org.apache.http.io.HttpTransportMetrics;
import org.apache.http.params.CoreConnectionPNames;
import org.apache.http.params.CoreProtocolPNames;
import org.apache.http.params.HttpParams;
import org.apache.http.params.HttpProtocolParams;
import org.apache.http.protocol.HTTP;
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 4.0
*/
public abstract class AbstractSessionInputBuffer implements SessionInputBuffer {
private InputStream instream;
private byte[] buffer;
private int bufferpos;
private int bufferlen;
private ByteArrayBuffer linebuffer = null;
private String charset = HTTP.US_ASCII;
private boolean ascii = true;
private int maxLineLen = -1;
private HttpTransportMetricsImpl metrics;
/**
* Initializes this session input buffer.
* <p>
* The following HTTP parameters affect the initialization:
* <p>
* The {@link CoreProtocolPNames#HTTP_ELEMENT_CHARSET}
* parameter determines the charset to be used for decoding HTTP lines. If
* not specified, <code>US-ASCII</code> will be used per default.
* <p>
* The {@link CoreConnectionPNames#MAX_LINE_LENGTH} parameter determines
* the maximum line length limit. If set to a positive value, any HTTP
* line exceeding this limit will cause an IOException. A negative or zero
* value will effectively disable the check. Per default the line length
* check is disabled.
*
* @param instream the source input stream.
* @param buffersize the size of the internal buffer.
* @param params HTTP parameters.
*
* @see CoreProtocolPNames#HTTP_ELEMENT_CHARSET
* @see CoreConnectionPNames#MAX_LINE_LENGTH
*/
protected void init(final InputStream instream, int buffersize, final HttpParams params) {
if (instream == null) {
throw new IllegalArgumentException("Input stream may not be null");
}
if (buffersize <= 0) {
throw new IllegalArgumentException("Buffer size may not be negative or zero");
}
if (params == null) {
throw new IllegalArgumentException("HTTP parameters may not be null");
}
this.instream = instream;
this.buffer = new byte[buffersize];
this.bufferpos = 0;
this.bufferlen = 0;
this.linebuffer = new ByteArrayBuffer(buffersize);
this.charset = HttpProtocolParams.getHttpElementCharset(params);
this.ascii = this.charset.equalsIgnoreCase(HTTP.US_ASCII)
|| this.charset.equalsIgnoreCase(HTTP.ASCII);
this.maxLineLen = params.getIntParameter(CoreConnectionPNames.MAX_LINE_LENGTH, -1);
this.metrics = new HttpTransportMetricsImpl();
}
protected 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 = this.instream.read(this.buffer, off, len);
if (l == -1) {
return -1;
} else {
this.bufferlen = off + l;
this.metrics.incrementBytesTransferred(l);
return l;
}
}
protected 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;
}
int noRead = 0;
while (!hasBufferedData()) {
noRead = fillBuffer();
if (noRead == -1) {
return -1;
}
}
int chunk = this.bufferlen - this.bufferpos;
if (chunk > len) {
chunk = len;
}
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 {
if (charbuffer == null) {
throw new IllegalArgumentException("Char array buffer may not be null");
}
this.linebuffer.clear();
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;
}
}
if (this.maxLineLen > 0 && this.linebuffer.length() >= this.maxLineLen) {
throw new IOException("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 l = this.linebuffer.length();
if (l > 0) {
if (this.linebuffer.byteAt(l - 1) == HTTP.LF) {
l--;
this.linebuffer.setLength(l);
}
// discard CR if found
if (l > 0) {
if (this.linebuffer.byteAt(l - 1) == HTTP.CR) {
l--;
this.linebuffer.setLength(l);
}
}
}
l = this.linebuffer.length();
if (this.ascii) {
charbuffer.append(this.linebuffer, 0, l);
} else {
// This is VERY memory inefficient, BUT since non-ASCII charsets are
// NOT meant to be used anyway, there's no point optimizing it
String s = new String(this.linebuffer.buffer(), 0, l, this.charset);
charbuffer.append(s);
}
return l;
}
private int lineFromReadBuffer(final CharArrayBuffer charbuffer, int pos)
throws IOException {
int off = this.bufferpos;
int len;
this.bufferpos = pos + 1;
if (pos > 0 && this.buffer[pos - 1] == HTTP.CR) {
// skip CR if found
pos--;
}
len = pos - off;
if (this.ascii) {
charbuffer.append(this.buffer, off, len);
} else {
// This is VERY memory inefficient, BUT since non-ASCII charsets are
// NOT meant to be used anyway, there's no point optimizing it
String s = new String(this.buffer, off, len, this.charset);
charbuffer.append(s);
}
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 HttpTransportMetrics getMetrics() {
return this.metrics;
}
}