/*
* The MIT License
*
* Copyright (c) 2004-2009, Sun Microsystems, Inc., Kohsuke Kawaguchi
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package hudson.util;
import org.apache.commons.io.output.ByteArrayOutputStream;
import java.io.FilterInputStream;
import java.io.InputStream;
import java.io.IOException;
/**
* {@link FilterInputStream} that buffers the first N bytes to a byte array on the side.
* This byte array can be then accessed later.
*
* <p>
* Useful for sniffing the content of the stream after the error is discovered.
*
* @author Kohsuke Kawaguchi
*/
public class HeadBufferingStream extends FilterInputStream {
private final ByteArrayOutputStream side;
private final int sideBufferSize;
public HeadBufferingStream(InputStream in, int sideBufferSize) {
super(in);
this.sideBufferSize = sideBufferSize;
this.side = new ByteArrayOutputStream(sideBufferSize);
}
@Override
public int read() throws IOException {
int i = in.read();
if(i>=0 && space()>0)
side.write(i);
return i;
}
@Override
public int read(byte b[], int off, int len) throws IOException {
int r = in.read(b, off, len);
if(r>0) {
int sp = space();
if(sp>0)
side.write(b,off,Math.min(r, sp));
}
return r;
}
/**
* Available space in the {@link #side} buffer.
*/
private int space() {
return sideBufferSize-side.size();
}
/**
* Read until we fill up the side buffer.
*/
public void fillSide() throws IOException {
byte[] buf = new byte[space()];
while(space()>0) {
if(read(buf)<0)
return;
}
}
/**
* Gets the side buffer content.
*/
public byte[] getSideBuffer() {
return side.toByteArray();
}
}