fileops: add convenience function is_dot_or_dotdot()

Signed-off-by: schu <schu-github@schulog.org>

src/fileops.c

@@ -231,13 +231,8 @@ int git_futils_direach(
 		size_t de_len;
 		int result;
 
-		/* always skip '.' and '..' */
-		if (de->d_name[0] == '.') {
-			if (de->d_name[1] == '\0')
-				continue;
-			if (de->d_name[1] == '.' && de->d_name[2] == '\0')
-				continue;
-		}
+		if (is_dot_or_dotdot(de->d_name))
+			continue;
 
 		de_len = strlen(de->d_name);
 		if (path_sz < wd_len + de_len + 1) {

src/fileops.h

@@ -102,6 +102,14 @@ extern int git_futils_mv_withpath(const char *from, const char *to);
  */
 extern git_off_t git_futils_filesize(git_file fd);
 
+/* Taken from git.git */
+static inline int is_dot_or_dotdot(const char *name)
+{
+	return (name[0] == '.' &&
+		(name[1] == '\0' ||
+		 (name[1] == '.' && name[2] == '\0')));
+}
+
 /**
  * Read-only map all or part of a file into memory.
  * When possible this function should favor a virtual memory