class FSTaskIdentityFingerprintStrategy(FingerprintStrategy):
  """Foursquare fork of Pants TaskIdentityFingerprintStrategy."""
  # TODO(mateo) See if upstream would be interested in these improvements.

  def __init__(self, task_fp):
    self._task_fp = task_fp or ''

  def compute_fingerprint(self, target):
    """
    :API: public
    """
    target_fp = target.payload.fingerprint()
    if target_fp is None:
      return None
    hasher = hashlib.sha1()
    hasher.update(target_fp)
    hasher.update(self._task_fp)
    return hasher.hexdigest()

  def __hash__(self):
    return hash(self._task_fp)

  def __eq__(self, other):
    return self._task_fp == other._task_fp