Add setter for ProgressMonitor to DiffCommand

Change-Id: I34f8b77a461e165d7d624dbd9a6944feadc57b8e

org.eclipse.jgit/src/org/eclipse/jgit/api/DiffCommand.java

@@ -55,8 +55,10 @@ import org.eclipse.jgit.api.errors.NoHeadException;
 import org.eclipse.jgit.diff.DiffEntry;
 import org.eclipse.jgit.diff.DiffFormatter;
 import org.eclipse.jgit.dircache.DirCacheIterator;
+import org.eclipse.jgit.lib.NullProgressMonitor;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.ObjectReader;
+import org.eclipse.jgit.lib.ProgressMonitor;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.treewalk.AbstractTreeIterator;
 import org.eclipse.jgit.treewalk.CanonicalTreeParser;
@@ -88,6 +90,8 @@ public class DiffCommand extends GitCommand<List<DiffEntry>> {
 
 	private String destinationPrefix;
 
+	private ProgressMonitor monitor = NullProgressMonitor.INSTANCE;
+
 	/**
 	 * @param repo
 	 */
@@ -107,6 +111,7 @@ public class DiffCommand extends GitCommand<List<DiffEntry>> {
 		final DiffFormatter diffFmt = new DiffFormatter(
 				new BufferedOutputStream(out));
 		diffFmt.setRepository(repo);
+		diffFmt.setProgressMonitor(monitor);
 		try {
 			if (cached) {
 				if (oldTree == null) {
@@ -247,4 +252,19 @@ public class DiffCommand extends GitCommand<List<DiffEntry>> {
 		this.destinationPrefix = destinationPrefix;
 		return this;
 	}
+
+	/**
+	 * The progress monitor associated with the diff operation. By default, this
+	 * is set to <code>NullProgressMonitor</code>
+	 *
+	 * @see NullProgressMonitor
+	 *
+	 * @param monitor
+	 *            a progress monitor
+	 * @return this instance
+	 */
+	public DiffCommand setProgressMonitor(ProgressMonitor monitor) {
+		this.monitor = monitor;
+		return this;
+	}
 }