From 07cae6e6c1d6982cf6b919e90e79330793c74a15 Mon Sep 17 00:00:00 2001
From: Lluis Sanchez <slluis.devel@gmail.com>
Date: Tue, 26 Oct 2010 11:18:18 +0200
Subject: [PATCH] Optimize DirCacheCheckout

When checking out a tree, files that are identical to the file in
the current index and working directory don't need to be updated.

Change-Id: I9e025a53facd42410796eae821baaeff684a25c5
Signed-off-by: Chris Aniszczyk <caniszczyk@gmail.com>
---
 .../src/org/eclipse/jgit/dircache/DirCacheCheckout.java  | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheCheckout.java b/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheCheckout.java
index 03d2b8e9c..f52150457 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheCheckout.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheCheckout.java
@@ -273,8 +273,13 @@ public void prescanOneTree()
 	void processEntry(CanonicalTreeParser m, DirCacheBuildIterator i,
 			WorkingTreeIterator f) {
 		if (m != null) {
-			update(m.getEntryPathString(), m.getEntryObjectId(),
-					m.getEntryFileMode());
+			if (i == null || f == null || !m.idEqual(i)
+					|| f.isModified(i.getDirCacheEntry(), true,
+							config_filemode(), repo.getFS())) {
+				update(m.getEntryPathString(), m.getEntryObjectId(),
+						m.getEntryFileMode());
+			} else
+				keep(i.getDirCacheEntry());
 		} else {
 			if (f != null) {
 				if (walk.isDirectoryFileConflict()) {