Avoid to duplicate commit message when is not encoded

When a commit message doesn't have encoding information
and encoding output is utf-8 (default) then an useless
xstrdup() of commit message is done.

If we assume most of users live in an utf-8 world, this
useless copy is the common case.

Performance issue found with KCachegrind.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/commit.c b/commit.c
index 4c5dfa9af0c8870bdd777264f35b7ff45f0a2f4c..dc5a0643f3d52797f29706595355fca824d9feda 100644 (file)
--- a/commit.c
+++ b/commit.c
@@ -721,7 +721,10 @@ static char *logmsg_reencode(const struct commit *commit,
        encoding = get_header(commit, "encoding");
        use_encoding = encoding ? encoding : utf8;
        if (!strcmp(use_encoding, output_encoding))
-               out = xstrdup(commit->buffer);
+               if (encoding) /* we'll strip encoding header later */
+                       out = xstrdup(commit->buffer);
+               else
+                       return NULL; /* nothing to do */
        else
                out = reencode_string(commit->buffer,
                                      output_encoding, use_encoding);