On Mon, Oct 28, 2019 at 01:01:49PM +0100, Johannes Schindelin wrote:
> > > @@ -349,10 +349,16 @@ static int check_common(const char *unmatched, void *value, void *baton)
> > > static void update_common_dir(struct strbuf *buf, int git_dir_len,
> > > const char *common_dir)
> > > {
> > > - char *base = buf->buf + git_dir_len;
> > > + char *base = buf->buf + git_dir_len, *base2 = NULL;
> > > +
> > > + if (ends_with(base, ".lock"))
> > > + base = base2 = xstrndup(base, strlen(base) - 5);
> >
> > Hm, this adds the magic number 5 and calls strlen(base) twice, because
> > ends_with() calls strip_suffix(), which calls strlen(). Calling
> > strip_suffix() directly would allow us to avoid the magic number and
> > the second strlen():
> >
> > size_t len;
> > if (strip_suffix(base, ".lock", &len))
> > base = base2 = xstrndup(base, len);
>
> Actually, we should probably avoid the extra allocation. Earlier, I was
> concerned about multi-threading issues when attempting to modify the
> `strbuf`. But then, we modify that `strbuf` a couple of lines later
> anyway,
Do we? You're right, we do indeed, because in replace_dir(buf, ...)
we call strbuf_splice(buf, ...).
OK, then your suggestion below is even better.
> so my fears were totally unfounded. Therefore, my current
> version reads like this:
>
> -- snip --
> int has_lock_suffix = strbuf_strip_suffix(buf, LOCK_SUFFIX);
>
> init_common_trie();
> if (trie_find(&common_trie, base, check_common, NULL) > 0)
> replace_dir(buf, git_dir_len, common_dir);
>
> if (has_lock_suffix)
> strbuf_addstr(buf, LOCK_SUFFIX);
> -- snap --
