| /* |
| * Copyright (C) 2010, Google Inc. |
| * and other copyright owners as documented in the project's IP log. |
| * |
| * This program and the accompanying materials are made available |
| * under the terms of the Eclipse Distribution License v1.0 which |
| * accompanies this distribution, is reproduced below, and is |
| * available at http://www.eclipse.org/org/documents/edl-v10.php |
| * |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or |
| * without modification, are permitted provided that the following |
| * conditions are met: |
| * |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * - Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following |
| * disclaimer in the documentation and/or other materials provided |
| * with the distribution. |
| * |
| * - Neither the name of the Eclipse Foundation, Inc. nor the |
| * names of its contributors may be used to endorse or promote |
| * products derived from this software without specific prior |
| * written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND |
| * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, |
| * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
| * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
| * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
| * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| package org.eclipse.jgit.lib; |
| |
| import java.util.concurrent.Semaphore; |
| import java.util.concurrent.atomic.AtomicInteger; |
| import java.util.concurrent.locks.ReentrantLock; |
| |
| /** |
| * Wrapper around the general {@link ProgressMonitor} to make it thread safe. |
| * |
| * Updates to the underlying ProgressMonitor are made only from the thread that |
| * allocated this wrapper. Callers are responsible for ensuring the allocating |
| * thread uses {@link #pollForUpdates()} or {@link #waitForCompletion()} to |
| * update the underlying ProgressMonitor. |
| * |
| * Only {@link #update(int)}, {@link #isCancelled()}, and {@link #endWorker()} |
| * may be invoked from a worker thread. All other methods of the ProgressMonitor |
| * interface can only be called from the thread that allocates this wrapper. |
| */ |
| public class ThreadSafeProgressMonitor implements ProgressMonitor { |
| private final ProgressMonitor pm; |
| |
| private final ReentrantLock lock; |
| |
| private final Thread mainThread; |
| |
| private final AtomicInteger workers; |
| |
| private final AtomicInteger pendingUpdates; |
| |
| private final Semaphore process; |
| |
| /** |
| * Wrap a ProgressMonitor to be thread safe. |
| * |
| * @param pm |
| * the underlying monitor to receive events. |
| */ |
| public ThreadSafeProgressMonitor(ProgressMonitor pm) { |
| this.pm = pm; |
| this.lock = new ReentrantLock(); |
| this.mainThread = Thread.currentThread(); |
| this.workers = new AtomicInteger(0); |
| this.pendingUpdates = new AtomicInteger(0); |
| this.process = new Semaphore(0); |
| } |
| |
| @Override |
| public void start(int totalTasks) { |
| if (!isMainThread()) |
| throw new IllegalStateException(); |
| pm.start(totalTasks); |
| } |
| |
| @Override |
| public void beginTask(String title, int totalWork) { |
| if (!isMainThread()) |
| throw new IllegalStateException(); |
| pm.beginTask(title, totalWork); |
| } |
| |
| /** Notify the monitor a worker is starting. */ |
| public void startWorker() { |
| startWorkers(1); |
| } |
| |
| /** |
| * Notify the monitor of workers starting. |
| * |
| * @param count |
| * the number of worker threads that are starting. |
| */ |
| public void startWorkers(int count) { |
| workers.addAndGet(count); |
| } |
| |
| /** Notify the monitor a worker is finished. */ |
| public void endWorker() { |
| if (workers.decrementAndGet() == 0) |
| process.release(); |
| } |
| |
| /** |
| * Non-blocking poll for pending updates. |
| * |
| * This method can only be invoked by the same thread that allocated this |
| * ThreadSafeProgressMonior. |
| */ |
| public void pollForUpdates() { |
| assert isMainThread(); |
| doUpdates(); |
| } |
| |
| /** |
| * Process pending updates and wait for workers to finish. |
| * |
| * This method can only be invoked by the same thread that allocated this |
| * ThreadSafeProgressMonior. |
| * |
| * @throws InterruptedException |
| * if the main thread is interrupted while waiting for |
| * completion of workers. |
| */ |
| public void waitForCompletion() throws InterruptedException { |
| assert isMainThread(); |
| while (0 < workers.get()) { |
| doUpdates(); |
| process.acquire(); |
| } |
| doUpdates(); |
| } |
| |
| private void doUpdates() { |
| int cnt = pendingUpdates.getAndSet(0); |
| if (0 < cnt) |
| pm.update(cnt); |
| } |
| |
| @Override |
| public void update(int completed) { |
| if (0 == pendingUpdates.getAndAdd(completed)) |
| process.release(); |
| } |
| |
| @Override |
| public boolean isCancelled() { |
| lock.lock(); |
| try { |
| return pm.isCancelled(); |
| } finally { |
| lock.unlock(); |
| } |
| } |
| |
| @Override |
| public void endTask() { |
| if (!isMainThread()) |
| throw new IllegalStateException(); |
| pm.endTask(); |
| } |
| |
| private boolean isMainThread() { |
| return Thread.currentThread() == mainThread; |
| } |
| } |