Added tools to retrieve CQ builders from a CQ config

third_party/google/protobuf/message_factory.py

+# 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.
+
+#PY25 compatible for GAE.
+#
+# Copyright 2012 Google Inc. All Rights Reserved.
+
+"""Provides a factory class for generating dynamic messages.
+
+The easiest way to use this class is if you have access to the FileDescriptor
+protos containing the messages you want to create you can just do the following:
+
+message_classes = message_factory.GetMessages(iterable_of_file_descriptors)
+my_proto_instance = message_classes['some.proto.package.MessageName']()
+"""
+
+__author__ = 'matthewtoia@google.com (Matt Toia)'
+
+import sys  ##PY25
+from google.protobuf import descriptor_database
+from google.protobuf import descriptor_pool
+from google.protobuf import message
+from google.protobuf import reflection
+
+
+class MessageFactory(object):
+  """Factory for creating Proto2 messages from descriptors in a pool."""
+
+  def __init__(self, pool=None):
+    """Initializes a new factory."""
+    self.pool = (pool or descriptor_pool.DescriptorPool(
+        descriptor_database.DescriptorDatabase()))
+
+    # local cache of all classes built from protobuf descriptors
+    self._classes = {}
+
+  def GetPrototype(self, descriptor):
+    """Builds a proto2 message class based on the passed in descriptor.
+
+    Passing a descriptor with a fully qualified name matching a previous
+    invocation will cause the same class to be returned.
+
+    Args:
+      descriptor: The descriptor to build from.
+
+    Returns:
+      A class describing the passed in descriptor.
+    """
+    if descriptor.full_name not in self._classes:
+      descriptor_name = descriptor.name
+      if sys.version_info[0] < 3:  ##PY25
+##!PY25      if str is bytes:  # PY2
+        descriptor_name = descriptor.name.encode('ascii', 'ignore')
+      result_class = reflection.GeneratedProtocolMessageType(
+          descriptor_name,
+          (message.Message,),
+          {'DESCRIPTOR': descriptor, '__module__': None})
+          # If module not set, it wrongly points to the reflection.py module.
+      self._classes[descriptor.full_name] = result_class
+      for field in descriptor.fields:
+        if field.message_type:
+          self.GetPrototype(field.message_type)
+      for extension in result_class.DESCRIPTOR.extensions:
+        if extension.containing_type.full_name not in self._classes:
+          self.GetPrototype(extension.containing_type)
+        extended_class = self._classes[extension.containing_type.full_name]
+        extended_class.RegisterExtension(extension)
+    return self._classes[descriptor.full_name]
+
+  def GetMessages(self, files):
+    """Gets all the messages from a specified file.
+
+    This will find and resolve dependencies, failing if the descriptor
+    pool cannot satisfy them.
+
+    Args:
+      files: The file names to extract messages from.
+
+    Returns:
+      A dictionary mapping proto names to the message classes. This will include
+      any dependent messages as well as any messages defined in the same file as
+      a specified message.
+    """
+    result = {}
+    for file_name in files:
+      file_desc = self.pool.FindFileByName(file_name)
+      for name, msg in file_desc.message_types_by_name.iteritems():
+        if file_desc.package:
+          full_name = '.'.join([file_desc.package, name])
+        else:
+          full_name = msg.name
+        result[full_name] = self.GetPrototype(
+            self.pool.FindMessageTypeByName(full_name))
+
+      # While the extension FieldDescriptors are created by the descriptor pool,
+      # the python classes created in the factory need them to be registered
+      # explicitly, which is done below.
+      #
+      # The call to RegisterExtension will specifically check if the
+      # extension was already registered on the object and either
+      # ignore the registration if the original was the same, or raise
+      # an error if they were different.
+
+      for name, extension in file_desc.extensions_by_name.iteritems():
+        if extension.containing_type.full_name not in self._classes:
+          self.GetPrototype(extension.containing_type)
+        extended_class = self._classes[extension.containing_type.full_name]
+        extended_class.RegisterExtension(extension)
+    return result
+
+
+_FACTORY = MessageFactory()
+
+
+def GetMessages(file_protos):
+  """Builds a dictionary of all the messages available in a set of files.
+
+  Args:
+    file_protos: A sequence of file protos to build messages out of.
+
+  Returns:
+    A dictionary mapping proto names to the message classes. This will include
+    any dependent messages as well as any messages defined in the same file as
+    a specified message.
+  """
+  for file_proto in file_protos:
+    _FACTORY.pool.Add(file_proto)
+  return _FACTORY.GetMessages([file_proto.name for file_proto in file_protos])