git_pathdup: returns xstrdup-ed copy of the formatted path

Signed-off-by: Junio C Hamano <gitster@pobox.com>

cache.h

@@ -484,6 +484,8 @@ extern char *mksnpath(char *buf, size_t n, const char *fmt, ...)
 	__attribute__((format (printf, 3, 4)));
 extern char *git_snpath(char *buf, size_t n, const char *fmt, ...)
 	__attribute__((format (printf, 3, 4)));
+extern char *git_pathdup(const char *fmt, ...)
+	__attribute__((format (printf, 1, 2)));
 
 /* Return a statically allocated filename matching the sha1 signature */
 extern char *mkpath(const char *fmt, ...) __attribute__((format (printf, 1, 2)));

path.c

@@ -47,10 +47,9 @@ char *mksnpath(char *buf, size_t n, const char *fmt, ...)
 	return cleanup_path(buf);
 }
 
-char *git_snpath(char *buf, size_t n, const char *fmt, ...)
+static char *git_vsnpath(char *buf, size_t n, const char *fmt, va_list args)
 {
 	const char *git_dir = get_git_dir();
-	va_list args;
 	size_t len;
 
 	len = strlen(git_dir);
@@ -59,9 +58,7 @@ char *git_snpath(char *buf, size_t n, const char *fmt, ...)
 	memcpy(buf, git_dir, len);
 	if (len && !is_dir_sep(git_dir[len-1]))
 		buf[len++] = '/';
-	va_start(args, fmt);
 	len += vsnprintf(buf + len, n - len, fmt, args);
-	va_end(args);
 	if (len >= n)
 		goto bad;
 	return cleanup_path(buf);
@@ -70,6 +67,25 @@ char *git_snpath(char *buf, size_t n, const char *fmt, ...)
 	return buf;
 }
 
+char *git_snpath(char *buf, size_t n, const char *fmt, ...)
+{
+	va_list args;
+	va_start(args, fmt);
+	(void)git_vsnpath(buf, n, fmt, args);
+	va_end(args);
+	return buf;
+}
+
+char *git_pathdup(const char *fmt, ...)
+{
+	char path[PATH_MAX];
+	va_list args;
+	va_start(args, fmt);
+	(void)git_vsnpath(path, sizeof(path), fmt, args);
+	va_end(args);
+	return xstrdup(path);
+}
+
 char *mkpath(const char *fmt, ...)
 {
 	va_list args;