Speed up handling of "only" paths in the CommitCommand

Use binary search to reduce the number of lookups for very large number
of paths.

Change-Id: I76a16594b756bffd95298897414485a9cd637819

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

@@ -46,6 +46,7 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.text.MessageFormat;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
 
@@ -147,6 +148,7 @@ public class CommitCommand extends GitCommand<RevCommit> {
 			ConcurrentRefUpdateException,
 			WrongRepositoryStateException {
 		checkCallable();
+		Collections.sort(only);
 
 		RepositoryState state = repo.getRepositoryState();
 		if (!state.canCommit())
@@ -452,18 +454,15 @@ public class CommitCommand extends GitCommand<RevCommit> {
 	 * @return the item's index in <code>only</code>; -1 if no item matches
 	 */
 	private int lookupOnly(String pathString) {
-		int i = 0;
-		for (String o : only) {
-			String p = pathString;
-			while (true) {
-				if (p.equals(o))
-					return i;
-				int l = p.lastIndexOf("/"); //$NON-NLS-1$
-				if (l < 1)
-					break;
-				p = p.substring(0, l);
-			}
-			i++;
+		String p = pathString;
+		while (true) {
+			int position = Collections.binarySearch(only, p);
+			if (position >= 0)
+				return position;
+			int l = p.lastIndexOf("/"); //$NON-NLS-1$
+			if (l < 1)
+				break;
+			p = p.substring(0, l);
 		}
 		return -1;
 	}