message: src.drake.git: Add rev_parse method.
diff: @@ -82,6 +82,13 @@ class Git(VirtualNode):
  hasher.update(self.version().encode('utf-8'))
  return hasher.hexdigest()
  + def rev_parse(self, revision = 'HEAD', short = False):
  + cmd = ['rev-parse']
  + if short:
  + cmd += ['--short']
  + cmd += [revision]
  + return self.__cmd(cmd)
  +
  def author_date(self):
  """The author date, as given by git %ai format."""
  if self.__author_date is None:
  