[PATCH] Detect renames in diff family.

This rips out the rename detection engine from diff-helper and moves it
to the diff core, and updates the internal calling convention used by
diff-tree family into the diff core.  In order to give the same option
name to diff-tree family as well as to diff-helper, I've changed the
earlier diff-helper '-r' option to '-M' (stands for Move; sorry but the
natural abbreviation 'r' for 'rename' is already taken for 'recursive').

Although I did a fair amount of test with the git-diff-tree with
existing rename commits in the core GIT repository, this should still be
considered beta (preview) release.  This patch depends on the diff-delta
infrastructure just committed.

This implements almost everything I wanted to see in this series of
patch, except a few minor cleanups in the calling convention into diff
core, but that will be a separate cleanup patch.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 14 insertions, 2 deletions

diff --git a/diff-cache.c b/diff-cache.c
index 4cfbcdb9ed..2bdea9cc3a 100644
--- a/diff-cache.c
+++ b/diff-cache.c
@@ -5,6 +5,7 @@ static int cached_only = 0;
 static int generate_patch = 0;
 static int match_nonexisting = 0;
 static int line_termination = '\n';
+static int detect_rename = 0;
 
 /* A file entry went away or appeared */
 static void show_file(const char *prefix, struct cache_entry *ce, unsigned char *sha1, unsigned int mode)
@@ -165,13 +166,14 @@ static void mark_merge_entries(void)
 }
 
 static char *diff_cache_usage =
-"git-diff-cache [-p] [-r] [-z] [-m] [--cached] <tree sha1>";
+"git-diff-cache [-p] [-r] [-z] [-m] [-M] [--cached] <tree-ish>";
 
 int main(int argc, char **argv)
 {
 	unsigned char tree_sha1[20];
 	void *tree;
 	unsigned long size;
+	int ret;
 
 	read_cache();
 	while (argc > 2) {
@@ -186,6 +188,10 @@ int main(int argc, char **argv)
 			generate_patch = 1;
 			continue;
 		}
+		if (!strcmp(arg, "-M")) {
+			generate_patch = detect_rename = 1;
+			continue;
+		}
 		if (!strcmp(arg, "-z")) {
 			line_termination = '\0';
 			continue;
@@ -204,6 +210,9 @@ int main(int argc, char **argv)
 	if (argc != 2 || get_sha1(argv[1], tree_sha1))
 		usage(diff_cache_usage);
 
+	if (generate_patch)
+		diff_setup(detect_rename, 0, 0, 0, 0);
+
 	mark_merge_entries();
 
 	tree = read_object_with_reference(tree_sha1, "tree", &size, 0);
@@ -212,5 +221,8 @@ int main(int argc, char **argv)
 	if (read_tree(tree, size, 1))
 		die("unable to read tree object %s", argv[1]);
 
-	return diff_cache(active_cache, active_nr);
+	ret = diff_cache(active_cache, active_nr);
+	if (generate_patch)
+		diff_flush();
+	return ret;
 }