Initial checkin of gRPC to third_party/

third_party/grpc/src/python/grpcio/grpc/framework/core/_protocol.py

Index: third_party/grpc/src/python/grpcio/grpc/framework/core/_protocol.py
diff --git a/third_party/grpc/src/python/grpcio/grpc/framework/core/_protocol.py b/third_party/grpc/src/python/grpcio/grpc/framework/core/_protocol.py
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+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""State and behavior for passing protocol objects in an operation."""
+
+import collections
+import enum
+
+from grpc.framework.core import _constants
+from grpc.framework.core import _interfaces
+from grpc.framework.core import _utilities
+from grpc.framework.foundation import callable_util
+from grpc.framework.interfaces.base import base
+
+_EXCEPTION_LOG_MESSAGE = 'Exception delivering protocol object!'
+
+_LOCAL_FAILURE_OUTCOME = _utilities.Outcome(
+    base.Outcome.Kind.LOCAL_FAILURE, None, None)
+
+
+class _Awaited(
+    collections.namedtuple('_Awaited', ('kind', 'value',))):
+
+  @enum.unique
+  class Kind(enum.Enum):
+    NOT_YET_ARRIVED = 'not yet arrived'
+    ARRIVED = 'arrived'
+
+_NOT_YET_ARRIVED = _Awaited(_Awaited.Kind.NOT_YET_ARRIVED, None)
+_ARRIVED_AND_NONE = _Awaited(_Awaited.Kind.ARRIVED, None)
+
+
+class _Transitory(
+    collections.namedtuple('_Transitory', ('kind', 'value',))):
+
+  @enum.unique
+  class Kind(enum.Enum):
+    NOT_YET_SEEN = 'not yet seen'
+    PRESENT = 'present'
+    GONE = 'gone'
+
+_NOT_YET_SEEN = _Transitory(_Transitory.Kind.NOT_YET_SEEN, None)
+_GONE = _Transitory(_Transitory.Kind.GONE, None)
+
+
+class _ProtocolManager(_interfaces.ProtocolManager):
+  """An implementation of _interfaces.ExpirationManager."""
+
+  def __init__(
+      self, protocol_receiver, lock, pool, termination_manager,
+      transmission_manager, expiration_manager):
+    """Constructor.
+
+    Args:
+      protocol_receiver: An _Awaited wrapping of the base.ProtocolReceiver to
+        which protocol objects should be passed during the operation. May be
+        of kind _Awaited.Kind.NOT_YET_ARRIVED if the customer's subscription is
+        not yet known and may be of kind _Awaited.Kind.ARRIVED but with a value
+        of None if the customer's subscription did not include a
+        ProtocolReceiver.
+      lock: The operation-wide lock.
+      pool: A thread pool.
+      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._pool = pool
+    self._termination_manager = termination_manager
+    self._transmission_manager = transmission_manager
+    self._expiration_manager = expiration_manager
+
+    self._protocol_receiver = protocol_receiver
+    self._context = _NOT_YET_SEEN
+
+  def _abort_and_notify(self, outcome):
+    if self._termination_manager.outcome is None:
+      self._termination_manager.abort(outcome)
+      self._transmission_manager.abort(outcome)
+      self._expiration_manager.terminate()
+
+  def _deliver(self, behavior, value):
+    def deliver():
+      delivery_outcome = callable_util.call_logging_exceptions(
+          behavior, _EXCEPTION_LOG_MESSAGE, value)
+      if delivery_outcome.kind is callable_util.Outcome.Kind.RAISED:
+        with self._lock:
+          self._abort_and_notify(_LOCAL_FAILURE_OUTCOME)
+    self._pool.submit(
+        callable_util.with_exceptions_logged(
+            deliver, _constants.INTERNAL_ERROR_LOG_MESSAGE))
+
+  def set_protocol_receiver(self, protocol_receiver):
+    """See _interfaces.ProtocolManager.set_protocol_receiver for spec."""
+    self._protocol_receiver = _Awaited(_Awaited.Kind.ARRIVED, protocol_receiver)
+    if (self._context.kind is _Transitory.Kind.PRESENT and
+        protocol_receiver is not None):
+      self._deliver(protocol_receiver.context, self._context.value)
+      self._context = _GONE
+
+  def accept_protocol_context(self, protocol_context):
+    """See _interfaces.ProtocolManager.accept_protocol_context for spec."""
+    if self._protocol_receiver.kind is _Awaited.Kind.ARRIVED:
+      if self._protocol_receiver.value is not None:
+        self._deliver(self._protocol_receiver.value.context, protocol_context)
+      self._context = _GONE
+    else:
+      self._context = _Transitory(_Transitory.Kind.PRESENT, protocol_context)
+
+
+def invocation_protocol_manager(
+    subscription, lock, pool, termination_manager, transmission_manager,
+    expiration_manager):
+  """Creates an _interfaces.ProtocolManager for invocation-side use.
+
+  Args:
+    subscription: The local customer's subscription to the operation.
+    lock: The operation-wide lock.
+    pool: A thread pool.
+    termination_manager: The _interfaces.TerminationManager for the operation.
+    transmission_manager: The _interfaces.TransmissionManager for the
+      operation.
+    expiration_manager: The _interfaces.ExpirationManager for the operation.
+  """
+  if subscription.kind is base.Subscription.Kind.FULL:
+    awaited_protocol_receiver = _Awaited(
+        _Awaited.Kind.ARRIVED, subscription.protocol_receiver)
+  else:
+    awaited_protocol_receiver = _ARRIVED_AND_NONE
+  return _ProtocolManager(
+      awaited_protocol_receiver, lock, pool, termination_manager,
+      transmission_manager, expiration_manager)
+
+
+def service_protocol_manager(
+    lock, pool, termination_manager, transmission_manager, expiration_manager):
+  """Creates an _interfaces.ProtocolManager for service-side use.
+
+  Args:
+    lock: The operation-wide lock.
+    pool: A thread pool.
+    termination_manager: The _interfaces.TerminationManager for the operation.
+    transmission_manager: The _interfaces.TransmissionManager for the
+      operation.
+    expiration_manager: The _interfaces.ExpirationManager for the operation.
+  """
+  return _ProtocolManager(
+      _NOT_YET_ARRIVED, lock, pool, termination_manager, transmission_manager,
+      expiration_manager)