def path(self):
        """Return the file path abstracted from VCS."""
        if (self.source_file.startswith('a/') and
                self.target_file.startswith('b/')):
            filepath = self.source_file[2:]
        elif (self.source_file.startswith('a/') and
              self.target_file == '/dev/null'):
            filepath = self.source_file[2:]
        elif (self.target_file.startswith('b/') and
              self.source_file == '/dev/null'):
            filepath = self.target_file[2:]
        else:
            filepath = self.source_file
        return filepath
Return the file path abstracted from VCS.