ls: avoid redundant processing when already escaping

This is mainly noticeable when the multi-byte code
within ls.c is triggered by multi-byte quotes.

$ seq 200000 | xargs touch
$ time ls-old -U --quoting=locale --hide-control-chars >/dev/null
real    0m0.483s
$ time ls-new -U --quoting=locale --hide-control-chars >/dev/null
real    0m0.430s

* src/ls.c (quote_name): Avoid rescanning the output looking for
unprintable chars when we know the quoting mode already escapes them.
* tests/misc/ls-misc.pl: Add tests for all quoting modes, with and
without -q, to verify this assumption.

1 files changed, 5 insertions, 1 deletions

diff --git a/src/ls.c b/src/ls.c
index 8d68a03e1..c22c536c0 100644
--- a/src/ls.c
+++ b/src/ls.c
@@ -4082,7 +4082,11 @@ quote_name (FILE *out, const char *name, struct quoting_options const *options,
       quotearg_buffer (buf, len + 1, name, -1, options);
     }
 
-  if (qmark_funny_chars)
+  enum quoting_style qs = get_quoting_style (options);
+
+  if (qmark_funny_chars
+      && (qs == shell_quoting_style || qs == shell_always_quoting_style
+          || qs == literal_quoting_style))
     {
       if (MB_CUR_MAX > 1)
         {