| /* |
| * 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.taskdefs; |
| |
| import org.apache.tools.ant.util.FileUtils; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.io.OutputStream; |
| import java.util.concurrent.CountDownLatch; |
| import java.util.concurrent.TimeUnit; |
| |
| /** |
| * Copies all data from an input stream to an output stream. |
| * |
| * @since Ant 1.2 |
| */ |
| public class StreamPumper implements Runnable { |
| |
| private static final int SMALL_BUFFER_SIZE = 128; |
| |
| private final InputStream is; |
| private final OutputStream os; |
| private volatile boolean askedToStop; |
| private volatile boolean finished; |
| private final boolean closeWhenExhausted; |
| private boolean autoflush = false; |
| private Exception exception = null; |
| private int bufferSize = SMALL_BUFFER_SIZE; |
| private boolean started = false; |
| private final boolean useAvailable; |
| private PostStopHandle postStopHandle; |
| |
| /** |
| * Create a new StreamPumper. |
| * |
| * @param is input stream to read data from |
| * @param os output stream to write data to. |
| * @param closeWhenExhausted if true, the output stream will be closed when |
| * the input is exhausted. |
| */ |
| public StreamPumper(InputStream is, OutputStream os, boolean closeWhenExhausted) { |
| this(is, os, closeWhenExhausted, false); |
| } |
| |
| |
| /** |
| * Create a new StreamPumper. |
| * <p><b>Note:</b> If you set useAvailable to true, you must |
| * explicitly invoke {@link #stop stop} or interrupt the |
| * corresponding Thread when you are done or the run method will |
| * never finish on some JVMs (namely those where available returns |
| * 0 on a closed stream). Setting it to true may also impact |
| * performance negatively. This flag should only be set to true |
| * if you intend to stop the pumper before the input stream gets |
| * closed.</p> |
| * |
| * @param is input stream to read data from |
| * @param os output stream to write data to. |
| * @param closeWhenExhausted if true, the output stream will be closed when |
| * the input is exhausted. |
| * @param useAvailable whether the pumper should use {@link |
| * java.io.InputStream#available available} to determine |
| * whether input is ready, thus trying to emulate |
| * non-blocking behavior. |
| * |
| * @since Ant 1.8.0 |
| */ |
| public StreamPumper(InputStream is, OutputStream os, |
| boolean closeWhenExhausted, |
| boolean useAvailable) { |
| this.is = is; |
| this.os = os; |
| this.closeWhenExhausted = closeWhenExhausted; |
| this.useAvailable = useAvailable; |
| } |
| |
| /** |
| * Create a new StreamPumper. |
| * |
| * @param is input stream to read data from |
| * @param os output stream to write data to. |
| */ |
| public StreamPumper(InputStream is, OutputStream os) { |
| this(is, os, false); |
| } |
| |
| /** |
| * Set whether data should be flushed through to the output stream. |
| * @param autoflush if true, push through data; if false, let it be buffered |
| * @since Ant 1.6.3 |
| */ |
| /*package*/ void setAutoflush(boolean autoflush) { |
| this.autoflush = autoflush; |
| } |
| |
| /** |
| * Copies data from the input stream to the output stream. |
| * |
| * Terminates as soon as the input stream is closed or an error occurs. |
| */ |
| public void run() { |
| synchronized (this) { |
| started = true; |
| } |
| finished = false; |
| |
| final byte[] buf = new byte[bufferSize]; |
| |
| try { |
| int length; |
| while (!this.askedToStop && !Thread.interrupted()) { |
| waitForInput(is); |
| |
| if (askedToStop || Thread.interrupted()) { |
| break; |
| } |
| |
| length = is.read(buf); |
| if (length < 0) { |
| // EOF |
| break; |
| } |
| if (length > 0) { |
| // we did read something, so write it out |
| os.write(buf, 0, length); |
| if (autoflush) { |
| os.flush(); |
| } |
| } |
| } |
| this.doPostStop(); |
| } catch (InterruptedException ie) { |
| // likely PumpStreamHandler trying to stop us |
| } catch (Exception e) { |
| synchronized (this) { |
| exception = e; |
| } |
| } finally { |
| if (closeWhenExhausted) { |
| FileUtils.close(os); |
| } |
| finished = true; |
| askedToStop = false; |
| synchronized (this) { |
| notifyAll(); |
| } |
| } |
| } |
| |
| /** |
| * Tells whether the end of the stream has been reached. |
| * @return true is the stream has been exhausted. |
| */ |
| public boolean isFinished() { |
| return finished; |
| } |
| |
| /** |
| * This method blocks until the StreamPumper finishes. |
| * @throws InterruptedException if interrupted. |
| * @see #isFinished() |
| */ |
| public synchronized void waitFor() throws InterruptedException { |
| while (!isFinished()) { |
| wait(); |
| } |
| } |
| |
| /** |
| * Set the size in bytes of the read buffer. |
| * @param bufferSize the buffer size to use. |
| * @throws IllegalStateException if the StreamPumper is already running. |
| */ |
| public synchronized void setBufferSize(int bufferSize) { |
| if (started) { |
| throw new IllegalStateException("Cannot set buffer size on a running StreamPumper"); |
| } |
| this.bufferSize = bufferSize; |
| } |
| |
| /** |
| * Get the size in bytes of the read buffer. |
| * |
| * @return the int size of the read buffer. |
| */ |
| public synchronized int getBufferSize() { |
| return bufferSize; |
| } |
| |
| /** |
| * Get the exception encountered, if any. |
| * @return the Exception encountered. |
| */ |
| public synchronized Exception getException() { |
| return exception; |
| } |
| |
| /** |
| * Stop the pumper as soon as possible. |
| * Note that it may continue to block on the input stream |
| * but it will really stop the thread as soon as it gets EOF |
| * or any byte, and it will be marked as finished. |
| * @return Returns a {@link PostStopHandle} for the callers to |
| * know if the status of post-stop activities, that happen, before this |
| * {@link StreamPumper} is actually finished |
| * @since Ant 1.6.3 |
| * @since Ant 10.2.0 this method returns a {@link PostStopHandle} |
| */ |
| /*package*/ |
| synchronized PostStopHandle stop() { |
| askedToStop = true; |
| postStopHandle = new PostStopHandle(); |
| notifyAll(); |
| return postStopHandle; |
| } |
| |
| private static final long POLL_INTERVAL = 100; |
| |
| private void waitForInput(InputStream is) |
| throws IOException, InterruptedException { |
| if (useAvailable) { |
| while (!askedToStop && is.available() == 0) { |
| if (Thread.interrupted()) { |
| throw new InterruptedException(); |
| } |
| |
| synchronized (this) { |
| this.wait(POLL_INTERVAL); |
| } |
| } |
| } |
| } |
| |
| private void doPostStop() throws IOException { |
| try { |
| final byte[] buf = new byte[bufferSize]; |
| int length; |
| // We were asked to stop, the contract allows us to do any non-blocking |
| // final bits of reads, before actually finishing. So we try and drain any (non-blocking) available |
| // data. We *don't* check the thread interrupt status, anymore, once we start draining this non-blocking |
| // available data, to allow us to cleanly write out any available data. |
| if (askedToStop) { |
| int bytesReadableWithoutBlocking; |
| while ((bytesReadableWithoutBlocking = is.available()) > 0) { |
| length = is.read(buf, 0, Math.min(bytesReadableWithoutBlocking, buf.length)); |
| if (length <= 0) { |
| break; |
| } |
| os.write(buf, 0, length); |
| } |
| } |
| // this can potentially be blocking, but that's OK since our post stop activity is allowed to |
| // cleanup/flush any data and the PostStopHandle let's the caller control over how long they want |
| // this to go, before actually interrupting the thread |
| os.flush(); |
| } finally { |
| if (this.postStopHandle != null) { |
| this.postStopHandle.latch.countDown(); |
| this.postStopHandle.inPostStopTasks = false; |
| } |
| } |
| } |
| |
| /** |
| * A handle that can be used after {@link #stop()} has been invoked to check if the |
| * {@link StreamPumper} is in the process of do some post-stop tasks (like flushing |
| * of streams), before finishing. |
| */ |
| final class PostStopHandle { |
| private boolean inPostStopTasks = true; |
| private final CountDownLatch latch = new CountDownLatch(1); |
| |
| /** |
| * Returns true if the {@link StreamPumper} is doing post-stop tasks (like flushing of streams). |
| * Else returns false. |
| * @return |
| */ |
| boolean isInPostStopTasks() { |
| return inPostStopTasks; |
| } |
| |
| /** |
| * Waits for a maximum of {@code timeout} time for the post-stop activities to complete. |
| * |
| * @param timeout The maximum amount of time to wait for the post-stop activities to complete |
| * @param timeUnit The unit of {@code timeout} |
| * @return Returns true if the post-stop activities completed within the specified {@code timeout}. |
| * Else returns false |
| * @throws InterruptedException If the current thread was interrupted while waiting |
| */ |
| boolean awaitPostStopCompletion(final long timeout, final TimeUnit timeUnit) throws InterruptedException { |
| return this.latch.await(timeout, timeUnit); |
| } |
| } |
| |
| } |