+ if ( $this->mimeCallback ) {
+ return call_user_func_array( $this->mimeCallback, func_get_args() );
+ }
+
+ $mime = null;
+ if ( $fsPath !== null && function_exists( 'finfo_file' ) ) {
+ $finfo = finfo_open( FILEINFO_MIME_TYPE );
+ $mime = finfo_file( $finfo, $fsPath );
+ finfo_close( $finfo );
+ }
+
+ return is_string( $mime ) ? $mime : 'unknown/unknown';