[PATCH 2/2] blame: introduce -u/--unique option

[Namhyung Kim <namhyung@gmail.com>]

-u/--unique option will find and use minimum length of unique
SHA-1 name. If -l option is specified also, it will have higher
priority, IOW git blame will use full 40-length SHA-1 name.

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
---
 builtin/blame.c |   18 +++++++++++++++++-
 1 files changed, 17 insertions(+), 1 deletions(-)

diff --git a/builtin/blame.c b/builtin/blame.c
index aa30ec5..9ea41bc 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -41,6 +41,7 @@ static int reverse;
 static int blank_boundary;
 static int incremental;
 static int xdl_opts;
+static int longest_uniq_sha1;
 
 static enum date_mode blame_date_mode = DATE_ISO8601;
 static size_t blame_date_width;
@@ -1618,6 +1619,7 @@ static const char *format_time(unsigned long time, const char *tz_str,
 #define OUTPUT_SHOW_SCORE      0100
 #define OUTPUT_NO_AUTHOR       0200
 #define OUTPUT_SHOW_EMAIL	0400
+#define OUTPUT_UNIQ_OBJECT_NAME	01000
 
 static void emit_porcelain(struct scoreboard *sb, struct blame_entry *ent)
 {
@@ -1664,14 +1666,22 @@ static void emit_other(struct scoreboard *sb, struct blame_entry *ent, int opt)
 	struct commit_info ci;
 	char hex[41];
 	int show_raw_time = !!(opt & OUTPUT_RAW_TIMESTAMP);
+	int sha1_len;
 
 	get_commit_info(suspect->commit, &ci, 1);
 	strcpy(hex, sha1_to_hex(suspect->commit->object.sha1));
 
+	if (opt & OUTPUT_LONG_OBJECT_NAME)
+		sha1_len = 40;
+	else if (opt & OUTPUT_UNIQ_OBJECT_NAME)
+		sha1_len = longest_uniq_sha1;
+	else
+		sha1_len = 8;
+
 	cp = nth_line(sb, ent->lno);
 	for (cnt = 0; cnt < ent->num_lines; cnt++) {
 		char ch;
-		int length = (opt & OUTPUT_LONG_OBJECT_NAME) ? 40 : 8;
+		int length = sha1_len;
 
 		if (suspect->commit->object.flags & UNINTERESTING) {
 			if (blank_boundary)
@@ -1842,6 +1852,7 @@ static void find_alignment(struct scoreboard *sb, int *option)
 	for (e = sb->ent; e; e = e->next) {
 		struct origin *suspect = e->suspect;
 		struct commit_info ci;
+		const char *sha1;
 		int num;
 
 		if (strcmp(suspect->path, sb->path))
@@ -1867,6 +1878,10 @@ static void find_alignment(struct scoreboard *sb, int *option)
 			longest_dst_lines = num;
 		if (largest_score < ent_score(sb, e))
 			largest_score = ent_score(sb, e);
+		sha1 = find_unique_abbrev(suspect->commit->object.sha1,
+					  MINIMUM_ABBREV);
+		if (longest_uniq_sha1 < strlen(sha1))
+			longest_uniq_sha1 = strlen(sha1);
 	}
 	max_orig_digits = lineno_width(longest_src_lines);
 	max_digits = lineno_width(longest_dst_lines);
@@ -2306,6 +2321,7 @@ int cmd_blame(int argc, const char **argv, const char *prefix)
 		OPT_BIT('s', NULL, &output_option, "Suppress author name and timestamp (Default: off)", OUTPUT_NO_AUTHOR),
 		OPT_BIT('e', "show-email", &output_option, "Show author email instead of name (Default: off)", OUTPUT_SHOW_EMAIL),
 		OPT_BIT('w', NULL, &xdl_opts, "Ignore whitespace differences", XDF_IGNORE_WHITESPACE),
+		OPT_BIT('u', "unique", &output_option, "Show minimum unique SHA-1 (Default: off)", OUTPUT_UNIQ_OBJECT_NAME),
 		OPT_STRING('S', NULL, &revs_file, "file", "Use revisions from <file> instead of calling git-rev-list"),
 		OPT_STRING(0, "contents", &contents_from, "file", "Use <file>'s contents as the final image"),
 		{ OPTION_CALLBACK, 'C', NULL, &opt, "score", "Find line copies within and across files", PARSE_OPT_OPTARG, blame_copy_callback },
-- 
1.7.4