[PATCH 07/25] list-files: add tag to each entry, filter duplicate tags

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

All entries have a two-letter tag. If all entries have the same tags,
tags are not displayed.

The outcome before and after this patch is the same. But it will be
useful in future when there are more than one type of entry.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 builtin/list-files.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 63 insertions(+), 1 deletion(-)

diff --git a/builtin/list-files.c b/builtin/list-files.c
index 51ff19d..ec9ca17 100644
--- a/builtin/list-files.c
+++ b/builtin/list-files.c
@@ -12,17 +12,20 @@ enum item_type {
 struct item {
 	enum item_type type;
 	const char *path;
+	char tag[2];
 	const struct cache_entry *ce;
 };
 
 struct item_list {
 	struct item *items;
 	int nr, alloc;
+	int tag_pos, tag_len;
 };
 
 static struct pathspec pathspec;
 static const char *prefix;
 static int prefix_length;
+static int show_tag = -1;
 
 static const char * const ls_usage[] = {
 	N_("git list-files [options] [<pathspec>...]"),
@@ -30,6 +33,7 @@ static const char * const ls_usage[] = {
 };
 
 struct option ls_options[] = {
+	OPT_BOOL(0, "tag", &show_tag, N_("show tags")),
 	OPT_END()
 };
 
@@ -52,10 +56,61 @@ static void populate_cached_entries(struct item_list *result,
 		item = result->items + result->nr++;
 		item->type = FROM_INDEX;
 		item->path = ce->name;
+		item->tag[0] = ' ';
+		item->tag[1] = ' ';
 		item->ce = ce;
 	}
 }
 
+static void cleanup_tags(struct item_list *result)
+{
+	int i, same_1 = 1, same_2 = 1;
+
+	if (!show_tag) {
+		result->tag_pos = 0;
+		result->tag_len = 0;
+		return;
+	}
+	if (show_tag > 0) {
+		result->tag_pos = 0;
+		result->tag_len = 2;
+		return;
+	}
+
+	for (i = 1; i < result->nr && (same_1 || same_2); i++) {
+		const char *s0 = result->items[i - 1].tag;
+		const char *s1 = result->items[i].tag;
+
+		same_1 = same_1 && s0[0] == s1[0];
+		same_2 = same_2 && s0[1] == s1[1];
+	}
+
+	if (same_1 && same_2) {
+		result->tag_pos = 0;
+		result->tag_len = 0;
+	} else if (same_1) {
+		result->tag_pos = 1;
+		result->tag_len = 1;
+	} else if (same_2) {
+		result->tag_pos = 0;
+		result->tag_len = 1;
+	} else {
+		result->tag_pos = 0;
+		result->tag_len = 2;
+	}
+}
+
+/* this is similar to quote_path_relative() except it does not clear sb */
+static void quote_item(struct strbuf *out, const struct item *item)
+{
+	static struct strbuf sb = STRBUF_INIT;
+	const char *rel;
+
+	strbuf_reset(&sb);
+	rel = relative_path(item->path, prefix, &sb);
+	quote_c_style(rel, out, NULL, 0);
+}
+
 static void display(const struct item_list *result)
 {
 	struct strbuf quoted = STRBUF_INIT;
@@ -67,7 +122,13 @@ static void display(const struct item_list *result)
 	for (i = 0; i < result->nr; i++) {
 		const struct item *item = result->items + i;
 
-		quote_path_relative(item->path, prefix, &quoted);
+		strbuf_reset(&quoted);
+		if (result->tag_len) {
+			strbuf_add(&quoted, item->tag + result->tag_pos,
+				   result->tag_len);
+			strbuf_addch(&quoted, ' ');
+		}
+		quote_item(&quoted, item);
 		printf("%s\n", quoted.buf);
 	}
 	strbuf_release(&quoted);
@@ -108,6 +169,7 @@ int cmd_list_files(int argc, const char **argv, const char *cmd_prefix)
 
 	memset(&result, 0, sizeof(result));
 	populate_cached_entries(&result, &the_index);
+	cleanup_tags(&result);
 	display(&result);
 	/* free-ing result seems unnecessary */
 	return 0;
-- 
2.3.0.rc1.137.g477eb31