real_path: create real_pathdup

Create real_pathdup which returns a caller owned string of the resolved
realpath based on the provide path.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

abspath.c

@@ -205,6 +205,19 @@ const char *real_path_if_valid(const char *path)
 	return strbuf_realpath(&realpath, path, 0);
 }
 
+char *real_pathdup(const char *path)
+{
+	struct strbuf realpath = STRBUF_INIT;
+	char *retval = NULL;
+
+	if (strbuf_realpath(&realpath, path, 0))
+		retval = strbuf_detach(&realpath, NULL);
+
+	strbuf_release(&realpath);
+
+	return retval;
+}
+
 /*
  * Use this to get an absolute path from a relative one. If you want
  * to resolve links, you should use real_path.

cache.h

@@ -1068,6 +1068,7 @@ char *strbuf_realpath(struct strbuf *resolved, const char *path,
 		      int die_on_error);
 const char *real_path(const char *path);
 const char *real_path_if_valid(const char *path);
+char *real_pathdup(const char *path);
 const char *absolute_path(const char *path);
 const char *remove_leading_path(const char *in, const char *prefix);
 const char *relative_path(const char *in, const char *prefix, struct strbuf *sb);