Honor pack.threads and perform delta search in parallel

If we have multiple CPUs available, packing usually goes faster
when each CPU is assigned a slice of the available search space.
The number of threads to use is guessed from the runtime if it
wasn't set by the caller, or wasn't set in the configuration.

Change-Id: If554fd8973db77632a52a0f45377dd6ec13fc220
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

1 files changed, 111 insertions, 0 deletions

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/ThreadSafeProgressMonitor.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/ThreadSafeProgressMonitor.java
new file mode 100644
index 0000000000..9708bb2f92
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/ThreadSafeProgressMonitor.java
@@ -0,0 +1,111 @@
+/*
+ * 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.locks.ReentrantLock;
+
+/**
+ * Wrapper around the general {@link ProgressMonitor} to make it thread safe.
+ */
+public class ThreadSafeProgressMonitor implements ProgressMonitor {
+	private final ProgressMonitor pm;
+
+	private final ReentrantLock lock;
+
+	/**
+	 * 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();
+	}
+
+	public void start(int totalTasks) {
+		lock.lock();
+		try {
+			pm.start(totalTasks);
+		} finally {
+			lock.unlock();
+		}
+	}
+
+	public void beginTask(String title, int totalWork) {
+		lock.lock();
+		try {
+			pm.beginTask(title, totalWork);
+		} finally {
+			lock.unlock();
+		}
+	}
+
+	public void update(int completed) {
+		lock.lock();
+		try {
+			pm.update(completed);
+		} finally {
+			lock.unlock();
+		}
+	}
+
+	public boolean isCancelled() {
+		lock.lock();
+		try {
+			return pm.isCancelled();
+		} finally {
+			lock.unlock();
+		}
+	}
+
+	public void endTask() {
+		lock.lock();
+		try {
+			pm.endTask();
+		} finally {
+			lock.unlock();
+		}
+	}
+}