src/python/grpcio/grpc/framework/core/_context.py

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"""State and behavior for operation context."""

import time

# _interfaces is referenced from specification in this module.
from grpc.framework.core import _interfaces  # pylint: disable=unused-import
from grpc.framework.interfaces.base import base


class OperationContext(base.OperationContext):
  """An implementation of interfaces.OperationContext."""

  def __init__(
      self, lock, termination_manager, transmission_manager,
      expiration_manager):
    """Constructor.

    Args:
      lock: The operation-wide lock.
      termination_manager: The _interfaces.TerminationManager for the operation.
      transmission_manager: The _interfaces.TransmissionManager for the
        operation.
      expiration_manager: The _interfaces.ExpirationManager for the operation.
    """
    self._lock = lock
    self._termination_manager = termination_manager
    self._transmission_manager = transmission_manager
    self._expiration_manager = expiration_manager

  def _abort(self, outcome):
    with self._lock:
      if self._termination_manager.outcome is None:
        self._termination_manager.abort(outcome)
        self._transmission_manager.abort(outcome)
        self._expiration_manager.terminate()

  def outcome(self):
    """See base.OperationContext.outcome for specification."""
    with self._lock:
      return self._termination_manager.outcome

  def add_termination_callback(self, callback):
    """See base.OperationContext.add_termination_callback."""
    with self._lock:
      if self._termination_manager.outcome is None:
        self._termination_manager.add_callback(callback)
        return None
      else:
        return self._termination_manager.outcome

  def time_remaining(self):
    """See base.OperationContext.time_remaining for specification."""
    with self._lock:
      deadline = self._expiration_manager.deadline()
    return max(0.0, deadline - time.time())

  def cancel(self):
    """See base.OperationContext.cancel for specification."""
    self._abort(base.Outcome.CANCELLED)

  def fail(self, exception):
    """See base.OperationContext.fail for specification."""
    self._abort(base.Outcome.LOCAL_FAILURE)