Initial Contribution
diff --git a/froofle/protobuf/service_reflection.py b/froofle/protobuf/service_reflection.py
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+# Protocol Buffers - Google's data interchange format
+# Copyright 2008 Google Inc. All rights reserved.
+# http://code.google.com/p/protobuf/
+#
+# 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.
+
+"""Contains metaclasses used to create protocol service and service stub
+classes from ServiceDescriptor objects at runtime.
+
+The GeneratedServiceType and GeneratedServiceStubType metaclasses are used to
+inject all useful functionality into the classes output by the protocol
+compiler at compile-time.
+"""
+
+__author__ = 'petar@google.com (Petar Petrov)'
+
+
+class GeneratedServiceType(type):
+
+ """Metaclass for service classes created at runtime from ServiceDescriptors.
+
+ Implementations for all methods described in the Service class are added here
+ by this class. We also create properties to allow getting/setting all fields
+ in the protocol message.
+
+ The protocol compiler currently uses this metaclass to create protocol service
+ classes at runtime. Clients can also manually create their own classes at
+ runtime, as in this example:
+
+ mydescriptor = ServiceDescriptor(.....)
+ class MyProtoService(service.Service):
+ __metaclass__ = GeneratedServiceType
+ DESCRIPTOR = mydescriptor
+ myservice_instance = MyProtoService()
+ ...
+ """
+
+ _DESCRIPTOR_KEY = 'DESCRIPTOR'
+
+ def __init__(cls, name, bases, dictionary):
+ """Creates a message service class.
+
+ Args:
+ name: Name of the class (ignored, but required by the metaclass
+ protocol).
+ bases: Base classes of the class being constructed.
+ dictionary: The class dictionary of the class being constructed.
+ dictionary[_DESCRIPTOR_KEY] must contain a ServiceDescriptor object
+ describing this protocol service type.
+ """
+ # Don't do anything if this class doesn't have a descriptor. This happens
+ # when a service class is subclassed.
+ if GeneratedServiceType._DESCRIPTOR_KEY not in dictionary:
+ return
+ descriptor = dictionary[GeneratedServiceType._DESCRIPTOR_KEY]
+ service_builder = _ServiceBuilder(descriptor)
+ service_builder.BuildService(cls)
+
+
+class GeneratedServiceStubType(GeneratedServiceType):
+
+ """Metaclass for service stubs created at runtime from ServiceDescriptors.
+
+ This class has similar responsibilities as GeneratedServiceType, except that
+ it creates the service stub classes.
+ """
+
+ _DESCRIPTOR_KEY = 'DESCRIPTOR'
+
+ def __init__(cls, name, bases, dictionary):
+ """Creates a message service stub class.
+
+ Args:
+ name: Name of the class (ignored, here).
+ bases: Base classes of the class being constructed.
+ dictionary: The class dictionary of the class being constructed.
+ dictionary[_DESCRIPTOR_KEY] must contain a ServiceDescriptor object
+ describing this protocol service type.
+ """
+ super(GeneratedServiceStubType, cls).__init__(name, bases, dictionary)
+ # Don't do anything if this class doesn't have a descriptor. This happens
+ # when a service stub is subclassed.
+ if GeneratedServiceStubType._DESCRIPTOR_KEY not in dictionary:
+ return
+ descriptor = dictionary[GeneratedServiceStubType._DESCRIPTOR_KEY]
+ service_stub_builder = _ServiceStubBuilder(descriptor)
+ service_stub_builder.BuildServiceStub(cls)
+
+
+class _ServiceBuilder(object):
+
+ """This class constructs a protocol service class using a service descriptor.
+
+ Given a service descriptor, this class constructs a class that represents
+ the specified service descriptor. One service builder instance constructs
+ exactly one service class. That means all instances of that class share the
+ same builder.
+ """
+
+ def __init__(self, service_descriptor):
+ """Initializes an instance of the service class builder.
+
+ Args:
+ service_descriptor: ServiceDescriptor to use when constructing the
+ service class.
+ """
+ self.descriptor = service_descriptor
+
+ def BuildService(self, cls):
+ """Constructs the service class.
+
+ Args:
+ cls: The class that will be constructed.
+ """
+
+ # CallMethod needs to operate with an instance of the Service class. This
+ # internal wrapper function exists only to be able to pass the service
+ # instance to the method that does the real CallMethod work.
+ def _WrapCallMethod(srvc, method_descriptor,
+ rpc_controller, request, callback):
+ self._CallMethod(srvc, method_descriptor,
+ rpc_controller, request, callback)
+ self.cls = cls
+ cls.CallMethod = _WrapCallMethod
+ cls.GetDescriptor = self._GetDescriptor
+ cls.GetRequestClass = self._GetRequestClass
+ cls.GetResponseClass = self._GetResponseClass
+ for method in self.descriptor.methods:
+ setattr(cls, method.name, self._GenerateNonImplementedMethod(method))
+
+ def _GetDescriptor(self):
+ """Retrieves the service descriptor.
+
+ Returns:
+ The descriptor of the service (of type ServiceDescriptor).
+ """
+ return self.descriptor
+
+ def _CallMethod(self, srvc, method_descriptor,
+ rpc_controller, request, callback):
+ """Calls the method described by a given method descriptor.
+
+ Args:
+ srvc: Instance of the service for which this method is called.
+ method_descriptor: Descriptor that represent the method to call.
+ rpc_controller: RPC controller to use for this method's execution.
+ request: Request protocol message.
+ callback: A callback to invoke after the method has completed.
+ """
+ if method_descriptor.containing_service != self.descriptor:
+ raise RuntimeError(
+ 'CallMethod() given method descriptor for wrong service type.')
+ method = getattr(srvc, method_descriptor.name)
+ method(rpc_controller, request, callback)
+
+ def _GetRequestClass(self, method_descriptor):
+ """Returns the class of the request protocol message.
+
+ Args:
+ method_descriptor: Descriptor of the method for which to return the
+ request protocol message class.
+
+ Returns:
+ A class that represents the input protocol message of the specified
+ method.
+ """
+ if method_descriptor.containing_service != self.descriptor:
+ raise RuntimeError(
+ 'GetRequestClass() given method descriptor for wrong service type.')
+ return method_descriptor.input_type._concrete_class
+
+ def _GetResponseClass(self, method_descriptor):
+ """Returns the class of the response protocol message.
+
+ Args:
+ method_descriptor: Descriptor of the method for which to return the
+ response protocol message class.
+
+ Returns:
+ A class that represents the output protocol message of the specified
+ method.
+ """
+ if method_descriptor.containing_service != self.descriptor:
+ raise RuntimeError(
+ 'GetResponseClass() given method descriptor for wrong service type.')
+ return method_descriptor.output_type._concrete_class
+
+ def _GenerateNonImplementedMethod(self, method):
+ """Generates and returns a method that can be set for a service methods.
+
+ Args:
+ method: Descriptor of the service method for which a method is to be
+ generated.
+
+ Returns:
+ A method that can be added to the service class.
+ """
+ return lambda inst, rpc_controller, request, callback: (
+ self._NonImplementedMethod(method.name, rpc_controller, callback))
+
+ def _NonImplementedMethod(self, method_name, rpc_controller, callback):
+ """The body of all methods in the generated service class.
+
+ Args:
+ method_name: Name of the method being executed.
+ rpc_controller: RPC controller used to execute this method.
+ callback: A callback which will be invoked when the method finishes.
+ """
+ rpc_controller.SetFailed('Method %s not implemented.' % method_name)
+ callback(None)
+
+
+class _ServiceStubBuilder(object):
+
+ """Constructs a protocol service stub class using a service descriptor.
+
+ Given a service descriptor, this class constructs a suitable stub class.
+ A stub is just a type-safe wrapper around an RpcChannel which emulates a
+ local implementation of the service.
+
+ One service stub builder instance constructs exactly one class. It means all
+ instances of that class share the same service stub builder.
+ """
+
+ def __init__(self, service_descriptor):
+ """Initializes an instance of the service stub class builder.
+
+ Args:
+ service_descriptor: ServiceDescriptor to use when constructing the
+ stub class.
+ """
+ self.descriptor = service_descriptor
+
+ def BuildServiceStub(self, cls):
+ """Constructs the stub class.
+
+ Args:
+ cls: The class that will be constructed.
+ """
+
+ def _ServiceStubInit(stub, rpc_channel):
+ stub.rpc_channel = rpc_channel
+ self.cls = cls
+ cls.__init__ = _ServiceStubInit
+ for method in self.descriptor.methods:
+ setattr(cls, method.name, self._GenerateStubMethod(method))
+
+ def _GenerateStubMethod(self, method):
+ return lambda inst, rpc_controller, request, callback: self._StubMethod(
+ inst, method, rpc_controller, request, callback)
+
+ def _StubMethod(self, stub, method_descriptor,
+ rpc_controller, request, callback):
+ """The body of all service methods in the generated stub class.
+
+ Args:
+ stub: Stub instance.
+ method_descriptor: Descriptor of the invoked method.
+ rpc_controller: Rpc controller to execute the method.
+ request: Request protocol message.
+ callback: A callback to execute when the method finishes.
+ """
+ stub.rpc_channel.CallMethod(
+ method_descriptor, rpc_controller, request,
+ method_descriptor.output_type._concrete_class, callback)