dir.c: git-status --ignored: don't scan the work tree twice

'git-status --ignored' still scans the work tree twice to collect
untracked and ignored files, respectively.

fill_directory / read_directory already supports collecting untracked and
ignored files in a single directory scan. However, the DIR_COLLECT_IGNORED
flag to enable this has some git-add specific side-effects (e.g. it
doesn't recurse into ignored directories, so listing ignored files with
--untracked=all doesn't work).

The DIR_SHOW_IGNORED flag doesn't list untracked files and returns ignored
files in dir_struct.entries[] (instead of dir_struct.ignored[] as
DIR_COLLECT_IGNORED). DIR_SHOW_IGNORED is used all throughout git.

We don't want to break the existing API, so lets introduce a new flag
DIR_SHOW_IGNORED_TOO that lists untracked as well as ignored files similar
to DIR_COLLECT_FILES, but will recurse into sub-directories based on the
other flags as DIR_SHOW_IGNORED does.

In dir.c::read_directory_recursive, add ignored files to either
dir_struct.entries[] or dir_struct.ignored[] based on the flags. Also move
the DIR_COLLECT_IGNORED case here so that filling result lists is in a
common place.

In wt-status.c::wt_status_collect_untracked, use the new flag and read
results from dir_struct.ignored[]. Remove the extra fill_directory call.

builtin/check-ignore.c doesn't call fill_directory, setting the git-add
specific DIR_COLLECT_IGNORED flag has no effect here. Remove for clarity.

Update API documentation to reflect the changes.

Performance: with this patch, 'git-status --ignored' is typically as fast
as 'git-status'.

Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 11 insertions, 13 deletions

diff --git a/wt-status.c b/wt-status.c
index 676b058..bf84a86 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -511,9 +511,12 @@ static void wt_status_collect_untracked(struct wt_status *s)
 	if (s->show_untracked_files != SHOW_ALL_UNTRACKED_FILES)
 		dir.flags |=
 			DIR_SHOW_OTHER_DIRECTORIES | DIR_HIDE_EMPTY_DIRECTORIES;
+	if (s->show_ignored_files)
+		dir.flags |= DIR_SHOW_IGNORED_TOO;
 	setup_standard_excludes(&dir);
 
 	fill_directory(&dir, s->pathspec);
+
 	for (i = 0; i < dir.nr; i++) {
 		struct dir_entry *ent = dir.entries[i];
 		if (cache_name_is_other(ent->name, ent->len) &&
@@ -522,22 +525,17 @@ static void wt_status_collect_untracked(struct wt_status *s)
 		free(ent);
 	}
 
-	if (s->show_ignored_files) {
-		dir.nr = 0;
-		dir.flags = DIR_SHOW_IGNORED;
-		if (s->show_untracked_files != SHOW_ALL_UNTRACKED_FILES)
-			dir.flags |= DIR_SHOW_OTHER_DIRECTORIES | DIR_HIDE_EMPTY_DIRECTORIES;
-		fill_directory(&dir, s->pathspec);
-		for (i = 0; i < dir.nr; i++) {
-			struct dir_entry *ent = dir.entries[i];
-			if (cache_name_is_other(ent->name, ent->len) &&
-			    match_pathspec(s->pathspec, ent->name, ent->len, 0, NULL))
-				string_list_insert(&s->ignored, ent->name);
-			free(ent);
-		}
+	for (i = 0; i < dir.ignored_nr; i++) {
+		struct dir_entry *ent = dir.ignored[i];
+		if (cache_name_is_other(ent->name, ent->len) &&
+		    match_pathspec(s->pathspec, ent->name, ent->len, 0, NULL))
+			string_list_insert(&s->ignored, ent->name);
+		free(ent);
 	}
 
 	free(dir.entries);
+	free(dir.ignored);
+	clear_directory(&dir);
 
 	if (advice_status_u_option) {
 		struct timeval t_end;