/
NonBlockingPumpReader.java
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/
NonBlockingPumpReader.java
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/*
* Copyright (c) 2002-2017, the original author or authors.
*
* This software is distributable under the BSD license. See the terms of the
* BSD license in the documentation provided with this software.
*
* https://opensource.org/licenses/BSD-3-Clause
*/
package org.jline.utils;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.io.Writer;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
public class NonBlockingPumpReader extends NonBlockingReader {
private static final int DEFAULT_BUFFER_SIZE = 4096;
private final char[] buffer;
private int read;
private int write;
private int count;
/** Main lock guarding all access */
final ReentrantLock lock;
/** Condition for waiting takes */
private final Condition notEmpty;
/** Condition for waiting puts */
private final Condition notFull;
private final Writer writer;
private boolean closed;
public NonBlockingPumpReader() {
this(DEFAULT_BUFFER_SIZE);
}
public NonBlockingPumpReader(int bufferSize) {
this.buffer = new char[bufferSize];
this.writer = new NbpWriter();
this.lock = new ReentrantLock();
this.notEmpty = lock.newCondition();
this.notFull = lock.newCondition();
}
public Writer getWriter() {
return this.writer;
}
@Override
public boolean ready() {
return available() > 0;
}
public int available() {
final ReentrantLock lock = this.lock;
lock.lock();
try {
return count;
} finally {
lock.unlock();
}
}
@Override
protected int read(long timeout, boolean isPeek) throws IOException {
final ReentrantLock lock = this.lock;
lock.lock();
try {
// Blocks until more input is available or the reader is closed.
if (!closed && count == 0) {
try {
notEmpty.await(timeout, TimeUnit.MILLISECONDS);
} catch (InterruptedException e) {
throw (IOException) new InterruptedIOException().initCause(e);
}
}
if (closed) {
return EOF;
} else if (count == 0) {
return READ_EXPIRED;
} else {
if (isPeek) {
return buffer[read];
} else {
int res = buffer[read];
if (++read == buffer.length) {
read = 0;
}
--count;
notFull.signal();
return res;
}
}
} finally {
lock.unlock();
}
}
@Override
public int readBuffered(char[] b) throws IOException {
if (b == null) {
throw new NullPointerException();
} else if (b.length == 0) {
return 0;
} else {
final ReentrantLock lock = this.lock;
lock.lock();
try {
if (!closed && count == 0) {
try {
notEmpty.await();
} catch (InterruptedException e) {
throw (IOException) new InterruptedIOException().initCause(e);
}
}
if (closed) {
return EOF;
} else if (count == 0) {
return READ_EXPIRED;
} else {
int r = Math.min(b.length, count);
for (int i = 0; i < r; i++) {
b[i] = buffer[read++];
if (read == buffer.length) {
read = 0;
}
}
count -= r;
notFull.signal();
return r;
}
} finally {
lock.unlock();
}
}
}
void write(char[] cbuf, int off, int len) throws IOException {
if (len > 0) {
final ReentrantLock lock = this.lock;
lock.lock();
try {
while (len > 0) {
// Blocks until there is new space available for buffering or the
// reader is closed.
if (!closed && count == buffer.length) {
try {
notFull.await();
} catch (InterruptedException e) {
throw (IOException) new InterruptedIOException().initCause(e);
}
}
if (closed) {
throw new IOException("Closed");
}
while (len > 0 && count < buffer.length) {
buffer[write++] = cbuf[off++];
count++;
len--;
if (write == buffer.length) {
write = 0;
}
}
notEmpty.signal();
}
} finally {
lock.unlock();
}
}
}
@Override
public void close() throws IOException {
final ReentrantLock lock = this.lock;
lock.lock();
try {
this.closed = true;
this.notEmpty.signalAll();
this.notFull.signalAll();
} finally {
lock.unlock();
}
}
private class NbpWriter extends Writer {
@Override
public void write(char[] cbuf, int off, int len) throws IOException {
NonBlockingPumpReader.this.write(cbuf, off, len);
}
@Override
public void flush() throws IOException {
}
@Override
public void close() throws IOException {
NonBlockingPumpReader.this.close();
}
}
}