replace strbuf_expand() with strbuf_expand_step()

Avoid the overhead of passing context to a callback function of
strbuf_expand() by using strbuf_expand_step() in a loop instead.  It
requires explicit handling of %% and unrecognized placeholders, but is
simpler, more direct and avoids void pointers.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 19 insertions, 42 deletions

diff --git a/daemon.c b/daemon.c
index 7139cc201d..3682bfdd08 100644
--- a/daemon.c
+++ b/daemon.c
@@ -144,42 +144,6 @@ static void NORETURN daemon_die(const char *err, va_list params)
 	exit(1);
 }
 
-struct expand_path_context {
-	const char *directory;
-	struct hostinfo *hostinfo;
-};
-
-static size_t expand_path(struct strbuf *sb, const char *placeholder, void *ctx)
-{
-	struct expand_path_context *context = ctx;
-	struct hostinfo *hi = context->hostinfo;
-
-	switch (placeholder[0]) {
-	case 'H':
-		strbuf_addbuf(sb, &hi->hostname);
-		return 1;
-	case 'C':
-		if (placeholder[1] == 'H') {
-			strbuf_addstr(sb, get_canon_hostname(hi));
-			return 2;
-		}
-		break;
-	case 'I':
-		if (placeholder[1] == 'P') {
-			strbuf_addstr(sb, get_ip_address(hi));
-			return 2;
-		}
-		break;
-	case 'P':
-		strbuf_addbuf(sb, &hi->tcp_port);
-		return 1;
-	case 'D':
-		strbuf_addstr(sb, context->directory);
-		return 1;
-	}
-	return 0;
-}
-
 static const char *path_ok(const char *directory, struct hostinfo *hi)
 {
 	static char rpath[PATH_MAX];
@@ -223,10 +187,7 @@ static const char *path_ok(const char *directory, struct hostinfo *hi)
 	}
 	else if (interpolated_path && hi->saw_extended_args) {
 		struct strbuf expanded_path = STRBUF_INIT;
-		struct expand_path_context context;
-
-		context.directory = directory;
-		context.hostinfo = hi;
+		const char *format = interpolated_path;
 
 		if (*dir != '/') {
 			/* Allow only absolute */
@@ -234,8 +195,24 @@ static const char *path_ok(const char *directory, struct hostinfo *hi)
 			return NULL;
 		}
 
-		strbuf_expand(&expanded_path, interpolated_path,
-			      expand_path, &context);
+		while (strbuf_expand_step(&expanded_path, &format)) {
+			if (skip_prefix(format, "%", &format))
+				strbuf_addch(&expanded_path, '%');
+			else if (skip_prefix(format, "H", &format))
+				strbuf_addbuf(&expanded_path, &hi->hostname);
+			else if (skip_prefix(format, "CH", &format))
+				strbuf_addstr(&expanded_path,
+					      get_canon_hostname(hi));
+			else if (skip_prefix(format, "IP", &format))
+				strbuf_addstr(&expanded_path,
+					      get_ip_address(hi));
+			else if (skip_prefix(format, "P", &format))
+				strbuf_addbuf(&expanded_path, &hi->tcp_port);
+			else if (skip_prefix(format, "D", &format))
+				strbuf_addstr(&expanded_path, directory);
+			else
+				strbuf_addch(&expanded_path, '%');
+		}
 
 		rlen = strlcpy(interp_path, expanded_path.buf,
 			       sizeof(interp_path));