1 files changed, 126 insertions, 0 deletions
diff --git a/src/python/_framework/base/packets/_emission.py b/src/python/_framework/base/packets/_emission.py
new file mode 100644
index 0000000000..b4be5eb0ff
--- /dev/null
+++ b/src/python/_framework/base/packets/_emission.py
@@ -0,0 +1,126 @@
+# 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 handling emitted values."""
+
+# packets is referenced from specifications in this module.
+from _framework.base.packets import _interfaces
+from _framework.base.packets import packets  # pylint: disable=unused-import
+
+
+class _EmissionManager(_interfaces.EmissionManager):
+  """An implementation of _interfaces.EmissionManager."""
+
+  def __init__(
+      self, lock, failure_kind, termination_manager, transmission_manager):
+    """Constructor.
+
+    Args:
+      lock: The operation-wide lock.
+      failure_kind: Whichever one of packets.Kind.SERVICED_FAILURE or
+        packets.Kind.SERVICER_FAILURE describes this object's methods being
+        called inappropriately by customer code.
+      termination_manager: The _interfaces.TerminationManager for the operation.
+      transmission_manager: The _interfaces.TransmissionManager for the
+        operation.
+    """
+    self._lock = lock
+    self._failure_kind = failure_kind
+    self._termination_manager = termination_manager
+    self._transmission_manager = transmission_manager
+    self._ingestion_manager = None
+    self._expiration_manager = None
+
+    self._emission_complete = False
+
+  def set_ingestion_manager_and_expiration_manager(
+      self, ingestion_manager, expiration_manager):
+    self._ingestion_manager = ingestion_manager
+    self._expiration_manager = expiration_manager
+
+  def _abort(self):
+    self._termination_manager.abort(self._failure_kind)
+    self._transmission_manager.abort(self._failure_kind)
+    self._ingestion_manager.abort()
+    self._expiration_manager.abort()
+
+  def consume(self, value):
+    with self._lock:
+      if self._emission_complete:
+        self._abort()
+      else:
+        self._transmission_manager.inmit(value, False)
+
+  def terminate(self):
+    with self._lock:
+      if not self._emission_complete:
+        self._termination_manager.emission_complete()
+        self._transmission_manager.inmit(None, True)
+        self._emission_complete = True
+
+  def consume_and_terminate(self, value):
+    with self._lock:
+      if self._emission_complete:
+        self._abort()
+      else:
+        self._termination_manager.emission_complete()
+        self._transmission_manager.inmit(value, True)
+        self._emission_complete = True
+
+
+def front_emission_manager(lock, termination_manager, transmission_manager):
+  """Creates an _interfaces.EmissionManager appropriate for front-side use.
+
+  Args:
+    lock: The operation-wide lock.
+    termination_manager: The _interfaces.TerminationManager for the operation.
+    transmission_manager: The _interfaces.TransmissionManager for the operation.
+
+  Returns:
+    An _interfaces.EmissionManager appropriate for front-side use.
+  """
+  return _EmissionManager(
+      lock, packets.Kind.SERVICED_FAILURE, termination_manager,
+      transmission_manager)
+
+
+def back_emission_manager(lock, termination_manager, transmission_manager):
+  """Creates an _interfaces.EmissionManager appropriate for back-side use.
+
+  Args:
+    lock: The operation-wide lock.
+    termination_manager: The _interfaces.TerminationManager for the operation.
+    transmission_manager: The _interfaces.TransmissionManager for the operation.
+
+  Returns:
+    An _interfaces.EmissionManager appropriate for back-side use.
+  """
+  return _EmissionManager(
+      lock, packets.Kind.SERVICER_FAILURE, termination_manager,
+      transmission_manager)