/* $Id$ */
/**
* 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.
*/
package org.apache.manifoldcf.connectorcommon.common;
import java.io.*;
/** Cross-thread input stream. Use this class when you have a helper thread
* reading from a socket, and you need the ability to read safely from a ManifoldCF
* worker thread.
*/
public class XThreadInputStream extends InputStream
{
private final byte[] buffer = new byte[65536];
private int startPoint = 0;
private int byteCount = 0;
private boolean streamEnd = false;
private IOException failureException = null;
private boolean abort = false;
private final InputStream sourceStream;
/** Constructor, from a given input stream. */
public XThreadInputStream(InputStream sourceStream)
{
this.sourceStream = sourceStream;
}
/** Constructor, from another source. */
public XThreadInputStream()
{
this.sourceStream = null;
}
/** Call this method to abort the stuffQueue() method.
*/
public void abort()
{
synchronized (this)
{
abort = true;
notifyAll();
}
}
/** This method is called from the helper thread side, to stuff bytes onto
* the queue when there is no input stream.
* It exits only when interrupted or done.
*/
public void stuffQueue(byte[] byteBuffer, int offset, int amount)
throws InterruptedException
{
while (amount > 0)
{
int maxToRead;
int readStartPoint;
synchronized (this)
{
if (abort || streamEnd)
return;
// Calculate amount to read
maxToRead = buffer.length - byteCount;
if (maxToRead == 0)
{
wait();
continue;
}
readStartPoint = (startPoint + byteCount) & (buffer.length-1);
}
if (readStartPoint + maxToRead >= buffer.length)
maxToRead = buffer.length - readStartPoint;
// Now, copy to buffer
int amt;
if (amount > maxToRead)
amt = maxToRead;
else
amt = amount;
System.arraycopy(byteBuffer,offset,buffer,readStartPoint,amt);
offset += amt;
amount -= amt;
synchronized (this)
{
byteCount += amt;
notifyAll();
}
}
}
/** Call this method when there is no more data to write.
*/
public void doneStuffingQueue()
{
synchronized (this)
{
streamEnd = true;
notifyAll();
}
}
/** This method is called from the helper thread side, to keep the queue
* stuffed from the input stream.
* It exits when the stream is empty, or when interrupted.
*/
public void stuffQueue()
throws IOException, InterruptedException
{
while (true)
{
int maxToRead;
int readStartPoint;
synchronized (this)
{
if (streamEnd || abort)
return;
// Calculate amount to read
maxToRead = buffer.length - byteCount;
if (maxToRead == 0)
{
wait();
continue;
}
readStartPoint = (startPoint + byteCount) & (buffer.length-1);
}
// See how to break up the reads into pieces. We only do one piece right now.
if (readStartPoint + maxToRead >= buffer.length)
maxToRead = buffer.length - readStartPoint;
int amt = -1;
IOException exception = null;
try
{
amt = sourceStream.read(buffer, readStartPoint, maxToRead);
}
catch (IOException e)
{
exception = e;
}
synchronized (this)
{
if (exception != null)
failureException = exception;
else if (amt == -1)
streamEnd = true;
else
byteCount += amt;
notifyAll();
}
}
}
/** Read a byte.
*/
@Override
public int read()
throws IOException
{
byte[] b = new byte[1];
int amt = read(b,0,1);
if (amt == -1)
return amt;
return ((int)b[0]) & 0xffff;
}
/** Read lots of bytes.
*/
@Override
public int read(byte[] b)
throws IOException
{
return read(b,0,b.length);
}
/** Read lots of specific bytes.
*/
@Override
public int read(byte[] b, int off, int len)
throws IOException
{
try
{
int totalAmt = 0;
while (true)
{
if (len == 0)
return totalAmt;
int copyLen;
synchronized (this)
{
copyLen = byteCount;
if (copyLen > len)
copyLen = len;
int remLen = buffer.length - startPoint;
if (copyLen > remLen)
copyLen = remLen;
if (copyLen == 0)
{
if (streamEnd)
{
if (totalAmt != 0)
return totalAmt;
return -1;
}
if (failureException != null)
throw failureException;
wait();
continue;
}
}
System.arraycopy(buffer, startPoint, b, off, copyLen);
totalAmt += copyLen;
off += copyLen;
len -= copyLen;
synchronized (this)
{
startPoint += copyLen;
startPoint &= (buffer.length - 1);
byteCount -= copyLen;
notifyAll();
}
}
}
catch (InterruptedException e)
{
throw new InterruptedIOException(e.getMessage());
}
}
/** Skip
*/
@Override
public long skip(long n)
throws IOException
{
// Do nothing
return 0L;
}
/** Get available.
*/
@Override
public int available()
throws IOException
{
// Not supported
return 0;
}
/** Mark.
*/
@Override
public void mark(int readLimit)
{
// Do nothing
}
/** Reset.
*/
@Override
public void reset()
throws IOException
{
// Do nothing
}
/** Check if mark is supported.
*/
@Override
public boolean markSupported()
{
// Not supported
return false;
}
/** Close.
*/
@Override
public void close()
throws IOException
{
// Do nothing; stream close is handled by the caller on the stuffer side
}
}