/*
* 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.tools.ant;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.WeakHashMap;
import org.apache.tools.ant.util.FileUtils;
/**
* Logs content written by a thread and forwards the buffers onto the
* project object which will forward the content to the appropriate
* task.
*
* @since 1.4
*/
public class DemuxOutputStream extends OutputStream {
/**
* A data class to store information about a buffer. Such information
* is stored on a per-thread basis.
*/
private static class BufferInfo {
/**
* The per-thread output stream.
*/
private ByteArrayOutputStream buffer;
/**
* Indicates we have just seen a carriage return. It may be part of
* a crlf pair or a single cr invoking processBuffer twice.
*/
private boolean crSeen = false;
}
/** Maximum buffer size. */
private static final int MAX_SIZE = 1024;
/** Initial buffer size. */
private static final int INITIAL_SIZE = 132;
/** Carriage return */
private static final int CR = 0x0d;
/** Linefeed */
private static final int LF = 0x0a;
/** Mapping from thread to buffer (Thread to BufferInfo). */
private WeakHashMap<Thread, BufferInfo> buffers = new WeakHashMap<>();
/**
* The project to send output to.
*/
private Project project;
/**
* Whether or not this stream represents an error stream.
*/
private boolean isErrorStream;
/**
* Creates a new instance of this class.
*
* @param project The project instance for which output is being
* demultiplexed. Must not be <code>null</code>.
* @param isErrorStream <code>true</code> if this is the error string,
* otherwise a normal output stream. This is
* passed to the project so it knows
* which stream it is receiving.
*/
public DemuxOutputStream(Project project, boolean isErrorStream) {
this.project = project;
this.isErrorStream = isErrorStream;
}
/**
* Returns the buffer associated with the current thread.
*
* @return a BufferInfo for the current thread to write data to
*/
private BufferInfo getBufferInfo() {
Thread current = Thread.currentThread();
return buffers.computeIfAbsent(current, x -> {
BufferInfo bufferInfo = new BufferInfo();
bufferInfo.buffer = new ByteArrayOutputStream(INITIAL_SIZE);
bufferInfo.crSeen = false;
return bufferInfo;
});
}
/**
* Resets the buffer for the current thread.
*/
private void resetBufferInfo() {
Thread current = Thread.currentThread();
BufferInfo bufferInfo = buffers.get(current);
FileUtils.close(bufferInfo.buffer);
bufferInfo.buffer = new ByteArrayOutputStream();
bufferInfo.crSeen = false;
}
/**
* Removes the buffer for the current thread.
*/
private void removeBuffer() {
Thread current = Thread.currentThread();
buffers.remove (current);
}
/**
* Writes the data to the buffer and flushes the buffer if a line
* separator is detected or if the buffer has reached its maximum size.
*
* @param cc data to log (byte).
* @exception IOException if the data cannot be written to the stream
*/
@Override
public void write(int cc) throws IOException {
final byte c = (byte) cc;
BufferInfo bufferInfo = getBufferInfo();
if (c == '\n') {
// LF is always end of line (i.e. CRLF or single LF)
bufferInfo.buffer.write(cc);
processBuffer(bufferInfo.buffer);
} else {
if (bufferInfo.crSeen) {
// CR without LF - send buffer then add char
processBuffer(bufferInfo.buffer);
}
// add into buffer
bufferInfo.buffer.write(cc);
}
bufferInfo.crSeen = (c == '\r');
if (!bufferInfo.crSeen && bufferInfo.buffer.size() > MAX_SIZE) {
processBuffer(bufferInfo.buffer);
}
}
/**
* Converts the buffer to a string and sends it to the project.
*
* @param buffer the ByteArrayOutputStream used to collect the output
* until a line separator is seen.
*
* @see Project#demuxOutput(String,boolean)
*/
protected void processBuffer(ByteArrayOutputStream buffer) {
String output = buffer.toString();
project.demuxOutput(output, isErrorStream);
resetBufferInfo();
}
/**
* Converts the buffer to a string and sends it to the project.
*
* @param buffer the ByteArrayOutputStream used to collect the output
* until a line separator is seen.
*
* @see Project#demuxOutput(String,boolean)
*/
protected void processFlush(ByteArrayOutputStream buffer) {
String output = buffer.toString();
project.demuxFlush(output, isErrorStream);
resetBufferInfo();
}
/**
* Equivalent to flushing the stream.
*
* @exception IOException if there is a problem closing the stream.
*
* @see #flush
*/
@Override
public void close() throws IOException {
flush();
removeBuffer();
}
/**
* Writes all remaining data in the buffer associated
* with the current thread to the project.
*
* @exception IOException if there is a problem flushing the stream.
*/
@Override
public void flush() throws IOException {
BufferInfo bufferInfo = getBufferInfo();
if (bufferInfo.buffer.size() > 0) {
processFlush(bufferInfo.buffer);
}
}
/**
* Write a block of characters to the output stream
*
* @param b the array containing the data
* @param off the offset into the array where data starts
* @param len the length of block
*
* @throws IOException if the data cannot be written into the stream.
*/
@Override
public void write(byte[] b, int off, int len) throws IOException {
// find the line breaks and pass other chars through in blocks
int offset = off;
int blockStartOffset = offset;
int remaining = len;
BufferInfo bufferInfo = getBufferInfo();
while (remaining > 0) {
while (remaining > 0 && b[offset] != LF && b[offset] != CR) {
offset++;
remaining--;
}
// either end of buffer or a line separator char
int blockLength = offset - blockStartOffset;
if (blockLength > 0) {
bufferInfo.buffer.write(b, blockStartOffset, blockLength);
}
while (remaining > 0 && (b[offset] == LF || b[offset] == CR)) {
write(b[offset]);
offset++;
remaining--;
}
blockStartOffset = offset;
}
}
}