[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, 21 insertions, 4 deletions

diff --git a/diff-tree.c b/diff-tree.c
index 59d12f2ba1..34c868d3ab 100644
--- a/diff-tree.c
+++ b/diff-tree.c
@@ -9,6 +9,7 @@ static int recursive = 0;
 static int read_stdin = 0;
 static int line_termination = '\n';
 static int generate_patch = 0;
+static int detect_rename = 0;
 static const char *header = NULL;
 static const char *header_prefix = "";
 
@@ -281,6 +282,18 @@ static int diff_tree_sha1(const unsigned char *old, const unsigned char *new, co
 	return retval;
 }
 
+static int diff_tree_sha1_top(const unsigned char *old,
+			      const unsigned char *new, const char *base)
+{
+	int ret;
+	if (generate_patch)
+		diff_setup(detect_rename, 0, 0, 0, 0);
+	ret = diff_tree_sha1(old, new, base);
+	if (generate_patch)
+		diff_flush();
+	return ret;
+}
+
 static int get_one_line(const char *msg, unsigned long len)
 {
 	int ret = 0;
@@ -377,7 +390,7 @@ static int diff_tree_commit(const unsigned char *commit, const char *name)
 		if (get_sha1_hex(buf + offset + 7, parent))
 			return -1;
 		header = generate_header(name, sha1_to_hex(parent), buf, size);
-		diff_tree_sha1(parent, commit, "");
+		diff_tree_sha1_top(parent, commit, "");
 		if (!header && verbose_header)
 			header_prefix = "\ndiff-tree ";
 		offset += 48;
@@ -401,14 +414,14 @@ static int diff_tree_stdin(char *line)
 		line[81] = 0;
 		sprintf(this_header, "%s (from %s)\n", line, line+41);
 		header = this_header;
-		return diff_tree_sha1(parent, commit, "");
+		return diff_tree_sha1_top(parent, commit, "");
 	}
 	line[40] = 0;
 	return diff_tree_commit(commit, line);
 }
 
 static char *diff_tree_usage =
-"diff-tree [-p] [-r] [-z] [--stdin] [-m] [-s] [-v] <tree sha1> <tree sha1>";
+"diff-tree [-p] [-r] [-z] [--stdin] [-M] [-m] [-s] [-v] <tree-ish> <tree-ish>";
 
 int main(int argc, char **argv)
 {
@@ -447,6 +460,10 @@ int main(int argc, char **argv)
 			recursive = generate_patch = 1;
 			continue;
 		}
+		if (!strcmp(arg, "-M")) {
+			detect_rename = recursive = generate_patch = 1;
+			continue;
+		}
 		if (!strcmp(arg, "-z")) {
 			line_termination = '\0';
 			continue;
@@ -490,7 +507,7 @@ int main(int argc, char **argv)
 		diff_tree_commit(sha1[0], NULL);
 		break;
 	case 2:
-		diff_tree_sha1(sha1[0], sha1[1], "");
+		diff_tree_sha1_top(sha1[0], sha1[1], "");
 		break;
 	}