text: # Protocol Buffers - Google's data interchange format
  # Copyright 2008 Google Inc.  All rights reserved.
  # https://developers.google.com/protocol-buffers/
  #
  # 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.
  
  """Descriptors essentially contain exactly the information found in a .proto
  file, in types that make this information accessible in Python.
  """
  
  __author__ = 'robinson@google.com (Will Robinson)'
  
  import threading
  import six
  
  from google.protobuf.internal import api_implementation
  
  _USE_C_DESCRIPTORS = False
  if api_implementation.Type() == 'cpp':
    # Used by MakeDescriptor in cpp mode
    import binascii
    import os
    from google.protobuf.pyext import _message
    _USE_C_DESCRIPTORS = getattr(_message, '_USE_C_DESCRIPTORS', False)
  
  
  class Error(Exception):
    """Base error for this module."""
  
  
  class TypeTransformationError(Error):
    """Error transforming between python proto type and corresponding C++ type."""
  
  
  if _USE_C_DESCRIPTORS:
    # This metaclass allows to override the behavior of code like
    #     isinstance(my_descriptor, FieldDescriptor)
    # and make it return True when the descriptor is an instance of the extension
    # type written in C++.
    class DescriptorMetaclass(type):
      def __instancecheck__(cls, obj):
        if super(DescriptorMetaclass, cls).__instancecheck__(obj):
          return True
        if isinstance(obj, cls._C_DESCRIPTOR_CLASS):
          return True
        return False
  else:
    # The standard metaclass; nothing changes.
    DescriptorMetaclass = type
  
  
  class _Lock(object):
    """Wrapper class of threading.Lock(), which is allowed by 'with'."""
  
    def __new__(cls):
      self = object.__new__(cls)
      self._lock = threading.Lock()  # pylint: disable=protected-access
      return self
  
    def __enter__(self):
      self._lock.acquire()
  
    def __exit__(self, exc_type, exc_value, exc_tb):
      self._lock.release()
  
  
  _lock = threading.Lock()
  
  
  class DescriptorBase(six.with_metaclass(DescriptorMetaclass)):
  
    """Descriptors base class.
  
    This class is the base of all descriptor classes. It provides common options
    related functionality.
  
    Attributes:
      has_options:  True if the descriptor has non-default options.  Usually it
          is not necessary to read this -- just call GetOptions() which will
          happily return the default instance.  However, it's sometimes useful
          for efficiency, and also useful inside the protobuf implementation to
          avoid some bootstrapping issues.
    """
  
    if _USE_C_DESCRIPTORS:
      # The class, or tuple of classes, that are considered as "virtual
      # subclasses" of this descriptor class.
      _C_DESCRIPTOR_CLASS = ()
  
    def __init__(self, options, serialized_options, options_class_name):
      """Initialize the descriptor given its options message and the name of the
      class of the options message. The name of the class is required in case
      the options message is None and has to be created.
      """
      self._options = options
      self._options_class_name = options_class_name
      self._serialized_options = serialized_options
  
      # Does this descriptor have non-default options?
      self.has_options = (options is not None) or (serialized_options is not None)
  
    def _SetOptions(self, options, options_class_name):
      """Sets the descriptor's options
  
      This function is used in generated proto2 files to update descriptor
      options. It must not be used outside proto2.
      """
      self._options = options
      self._options_class_name = options_class_name
  
      # Does this descriptor have non-default options?
      self.has_options = options is not None
  
    def GetOptions(self):
      """Retrieves descriptor options.
  
      This method returns the options set or creates the default options for the
      descriptor.
      """
      if self._options:
        return self._options
  
      from google.protobuf import descriptor_pb2
      try:
        options_class = getattr(descriptor_pb2,
                                self._options_class_name)
      except AttributeError:
        raise RuntimeError('Unknown options class name %s!' %
                           (self._options_class_name))
  
      with _lock:
        if self._serialized_options is None:
          self._options = options_class()
        else:
          self._options = _ParseOptions(options_class(),
                                        self._serialized_options)
  
        return self._options
  
  
  class _NestedDescriptorBase(DescriptorBase):
    """Common class for descriptors that can be nested."""
  
    def __init__(self, options, options_class_name, name, full_name,
                 file, containing_type, serialized_start=None,
                 serialized_end=None, serialized_options=None):
      """Constructor.
  
      Args:
        options: Protocol message options or None
          to use default message options.
        options_class_name: (str) The class name of the above options.
  
        name: (str) Name of this protocol message type.
        full_name: (str) Fully-qualified name of this protocol message type,
          which will include protocol "package" name and the name of any
          enclosing types.
        file: (FileDescriptor) Reference to file info.
        containing_type: if provided, this is a nested descriptor, with this
          descriptor as parent, otherwise None.
        serialized_start: The start index (inclusive) in block in the
          file.serialized_pb that describes this descriptor.
        serialized_end: The end index (exclusive) in block in the
          file.serialized_pb that describes this descriptor.
        serialized_options: Protocol message serilized options or None.
      """
      super(_NestedDescriptorBase, self).__init__(
          options, serialized_options, options_class_name)
  
      self.name = name
      # TODO(falk): Add function to calculate full_name instead of having it in
      #             memory?
      self.full_name = full_name
      self.file = file
      self.containing_type = containing_type
  
      self._serialized_start = serialized_start
      self._serialized_end = serialized_end
  
    def CopyToProto(self, proto):
      """Copies this to the matching proto in descriptor_pb2.
  
      Args:
        proto: An empty proto instance from descriptor_pb2.
  
      Raises:
        Error: If self couldnt be serialized, due to to few constructor arguments.
      """
      if (self.file is not None and
          self._serialized_start is not None and
          self._serialized_end is not None):
        proto.ParseFromString(self.file.serialized_pb[
            self._serialized_start:self._serialized_end])
      else:
        raise Error('Descriptor does not contain serialization.')
  
  
  class Descriptor(_NestedDescriptorBase):
  
    """Descriptor for a protocol message type.
  
    A Descriptor instance has the following attributes:
  
      name: (str) Name of this protocol message type.
      full_name: (str) Fully-qualified name of this protocol message type,
        which will include protocol "package" name and the name of any
        enclosing types.
  
      containing_type: (Descriptor) Reference to the descriptor of the
        type containing us, or None if this is top-level.
  
      fields: (list of FieldDescriptors) Field descriptors for all
        fields in this type.
      fields_by_number: (dict int -> FieldDescriptor) Same FieldDescriptor
        objects as in |fields|, but indexed by "number" attribute in each
        FieldDescriptor.
      fields_by_name: (dict str -> FieldDescriptor) Same FieldDescriptor
        objects as in |fields|, but indexed by "name" attribute in each
        FieldDescriptor.
      fields_by_camelcase_name: (dict str -> FieldDescriptor) Same
        FieldDescriptor objects as in |fields|, but indexed by
        "camelcase_name" attribute in each FieldDescriptor.
  
      nested_types: (list of Descriptors) Descriptor references
        for all protocol message types nested within this one.
      nested_types_by_name: (dict str -> Descriptor) Same Descriptor
        objects as in |nested_types|, but indexed by "name" attribute
        in each Descriptor.
  
      enum_types: (list of EnumDescriptors) EnumDescriptor references
        for all enums contained within this type.
      enum_types_by_name: (dict str ->EnumDescriptor) Same EnumDescriptor
        objects as in |enum_types|, but indexed by "name" attribute
        in each EnumDescriptor.
      enum_values_by_name: (dict str -> EnumValueDescriptor) Dict mapping
        from enum value name to EnumValueDescriptor for that value.
  
      extensions: (list of FieldDescriptor) All extensions defined directly
        within this message type (NOT within a nested type).
      extensions_by_name: (dict, string -> FieldDescriptor) Same FieldDescriptor
        objects as |extensions|, but indexed by "name" attribute of each
        FieldDescriptor.
  
      is_extendable:  Does this type define any extension ranges?
  
      oneofs: (list of OneofDescriptor) The list of descriptors for oneof fields
        in this message.
      oneofs_by_name: (dict str -> OneofDescriptor) Same objects as in |oneofs|,
        but indexed by "name" attribute.
  
      file: (FileDescriptor) Reference to file descriptor.
    """
  
    if _USE_C_DESCRIPTORS:
      _C_DESCRIPTOR_CLASS = _message.Descriptor
  
      def __new__(cls, name, full_name, filename, containing_type, fields,
                  nested_types, enum_types, extensions, options=None,
                  serialized_options=None,
                  is_extendable=True, extension_ranges=None, oneofs=None,
                  file=None, serialized_start=None, serialized_end=None,  # pylint: disable=redefined-builtin
                  syntax=None):
        _message.Message._CheckCalledFromGeneratedFile()
        return _message.default_pool.FindMessageTypeByName(full_name)
  
    # NOTE(tmarek): The file argument redefining a builtin is nothing we can
    # fix right now since we don't know how many clients already rely on the
    # name of the argument.
    def __init__(self, name, full_name, filename, containing_type, fields,
                 nested_types, enum_types, extensions, options=None,
                 serialized_options=None,
                 is_extendable=True, extension_ranges=None, oneofs=None,
                 file=None, serialized_start=None, serialized_end=None,  # pylint: disable=redefined-builtin
                 syntax=None):
      """Arguments to __init__() are as described in the description
      of Descriptor fields above.
  
      Note that filename is an obsolete argument, that is not used anymore.
      Please use file.name to access this as an attribute.
      """
      super(Descriptor, self).__init__(
          options, 'MessageOptions', name, full_name, file,
          containing_type, serialized_start=serialized_start,
          serialized_end=serialized_end, serialized_options=serialized_options)
  
      # We have fields in addition to fields_by_name and fields_by_number,
      # so that:
      #   1. Clients can index fields by "order in which they're listed."
      #   2. Clients can easily iterate over all fields with the terse
      #      syntax: for f in descriptor.fields: ...
      self.fields = fields
      for field in self.fields:
        field.containing_type = self
      self.fields_by_number = dict((f.number, f) for f in fields)
      self.fields_by_name = dict((f.name, f) for f in fields)
      self._fields_by_camelcase_name = None
  
      self.nested_types = nested_types
      for nested_type in nested_types:
        nested_type.containing_type = self
      self.nested_types_by_name = dict((t.name, t) for t in nested_types)
  
      self.enum_types = enum_types
      for enum_type in self.enum_types:
        enum_type.containing_type = self
      self.enum_types_by_name = dict((t.name, t) for t in enum_types)
      self.enum_values_by_name = dict(
          (v.name, v) for t in enum_types for v in t.values)
  
      self.extensions = extensions
      for extension in self.extensions:
        extension.extension_scope = self
      self.extensions_by_name = dict((f.name, f) for f in extensions)
      self.is_extendable = is_extendable
      self.extension_ranges = extension_ranges
      self.oneofs = oneofs if oneofs is not None else []
      self.oneofs_by_name = dict((o.name, o) for o in self.oneofs)
      for oneof in self.oneofs:
        oneof.containing_type = self
      self.syntax = syntax or "proto2"
  
    @property
    def fields_by_camelcase_name(self):
      if self._fields_by_camelcase_name is None:
        self._fields_by_camelcase_name = dict(
            (f.camelcase_name, f) for f in self.fields)
      return self._fields_by_camelcase_name
  
    def EnumValueName(self, enum, value):
      """Returns the string name of an enum value.
  
      This is just a small helper method to simplify a common operation.
  
      Args:
        enum: string name of the Enum.
        value: int, value of the enum.
  
      Returns:
        string name of the enum value.
  
      Raises:
        KeyError if either the Enum doesn't exist or the value is not a valid
          value for the enum.
      """
      return self.enum_types_by_name[enum].values_by_number[value].name
  
    def CopyToProto(self, proto):
      """Copies this to a descriptor_pb2.DescriptorProto.
  
      Args:
        proto: An empty descriptor_pb2.DescriptorProto.
      """
      # This function is overridden to give a better doc comment.
      super(Descriptor, self).CopyToProto(proto)
  
  
  # TODO(robinson): We should have aggressive checking here,
  # for example:
  #   * If you specify a repeated field, you should not be allowed
  #     to specify a default value.
  #   * [Other examples here as needed].
  #
  # TODO(robinson): for this and other *Descriptor classes, we
  # might also want to lock things down aggressively (e.g.,
  # prevent clients from setting the attributes).  Having
  # stronger invariants here in general will reduce the number
  # of runtime checks we must do in reflection.py...
  class FieldDescriptor(DescriptorBase):
  
    """Descriptor for a single field in a .proto file.
  
    A FieldDescriptor instance has the following attributes:
  
      name: (str) Name of this field, exactly as it appears in .proto.
      full_name: (str) Name of this field, including containing scope.  This is
        particularly relevant for extensions.
      camelcase_name: (str) Camelcase name of this field.
      index: (int) Dense, 0-indexed index giving the order that this
        field textually appears within its message in the .proto file.
      number: (int) Tag number declared for this field in the .proto file.
  
      type: (One of the TYPE_* constants below) Declared type.
      cpp_type: (One of the CPPTYPE_* constants below) C++ type used to
        represent this field.
  
      label: (One of the LABEL_* constants below) Tells whether this
        field is optional, required, or repeated.
      has_default_value: (bool) True if this field has a default value defined,
        otherwise false.
      default_value: (Varies) Default value of this field.  Only
        meaningful for non-repeated scalar fields.  Repeated fields
        should always set this to [], and non-repeated composite
        fields should always set this to None.
  
      containing_type: (Descriptor) Descriptor of the protocol message
        type that contains this field.  Set by the Descriptor constructor
        if we're passed into one.
        Somewhat confusingly, for extension fields, this is the
        descriptor of the EXTENDED message, not the descriptor
        of the message containing this field.  (See is_extension and
        extension_scope below).
      message_type: (Descriptor) If a composite field, a descriptor
        of the message type contained in this field.  Otherwise, this is None.
      enum_type: (EnumDescriptor) If this field contains an enum, a
        descriptor of that enum.  Otherwise, this is None.
  
      is_extension: True iff this describes an extension field.
      extension_scope: (Descriptor) Only meaningful if is_extension is True.
        Gives the message that immediately contains this extension field.
        Will be None iff we're a top-level (file-level) extension field.
  
      options: (descriptor_pb2.FieldOptions) Protocol message field options or
        None to use default field options.
  
      containing_oneof: (OneofDescriptor) If the field is a member of a oneof
        union, contains its descriptor. Otherwise, None.
  
      file: (FileDescriptor) Reference to file descriptor.
    """
  
    # Must be consistent with C++ FieldDescriptor::Type enum in
    # descriptor.h.
    #
    # TODO(robinson): Find a way to eliminate this repetition.
    TYPE_DOUBLE         = 1
    TYPE_FLOAT          = 2
    TYPE_INT64          = 3
    TYPE_UINT64         = 4
    TYPE_INT32          = 5
    TYPE_FIXED64        = 6
    TYPE_FIXED32        = 7
    TYPE_BOOL           = 8
    TYPE_STRING         = 9
    TYPE_GROUP          = 10
    TYPE_MESSAGE        = 11
    TYPE_BYTES          = 12
    TYPE_UINT32         = 13
    TYPE_ENUM           = 14
    TYPE_SFIXED32       = 15
    TYPE_SFIXED64       = 16
    TYPE_SINT32         = 17
    TYPE_SINT64         = 18
    MAX_TYPE            = 18
  
    # Must be consistent with C++ FieldDescriptor::CppType enum in
    # descriptor.h.
    #
    # TODO(robinson): Find a way to eliminate this repetition.
    CPPTYPE_INT32       = 1
    CPPTYPE_INT64       = 2
    CPPTYPE_UINT32      = 3
    CPPTYPE_UINT64      = 4
    CPPTYPE_DOUBLE      = 5
    CPPTYPE_FLOAT       = 6
    CPPTYPE_BOOL        = 7
    CPPTYPE_ENUM        = 8
    CPPTYPE_STRING      = 9
    CPPTYPE_MESSAGE     = 10
    MAX_CPPTYPE         = 10
  
    _PYTHON_TO_CPP_PROTO_TYPE_MAP = {
        TYPE_DOUBLE: CPPTYPE_DOUBLE,
        TYPE_FLOAT: CPPTYPE_FLOAT,
        TYPE_ENUM: CPPTYPE_ENUM,
        TYPE_INT64: CPPTYPE_INT64,
        TYPE_SINT64: CPPTYPE_INT64,
        TYPE_SFIXED64: CPPTYPE_INT64,
        TYPE_UINT64: CPPTYPE_UINT64,
        TYPE_FIXED64: CPPTYPE_UINT64,
        TYPE_INT32: CPPTYPE_INT32,
        TYPE_SFIXED32: CPPTYPE_INT32,
        TYPE_SINT32: CPPTYPE_INT32,
        TYPE_UINT32: CPPTYPE_UINT32,
        TYPE_FIXED32: CPPTYPE_UINT32,
        TYPE_BYTES: CPPTYPE_STRING,
        TYPE_STRING: CPPTYPE_STRING,
        TYPE_BOOL: CPPTYPE_BOOL,
        TYPE_MESSAGE: CPPTYPE_MESSAGE,
        TYPE_GROUP: CPPTYPE_MESSAGE
        }
  
    # Must be consistent with C++ FieldDescriptor::Label enum in
    # descriptor.h.
    #
    # TODO(robinson): Find a way to eliminate this repetition.
    LABEL_OPTIONAL      = 1
    LABEL_REQUIRED      = 2
    LABEL_REPEATED      = 3
    MAX_LABEL           = 3
  
    # Must be consistent with C++ constants kMaxNumber, kFirstReservedNumber,
    # and kLastReservedNumber in descriptor.h
    MAX_FIELD_NUMBER = (1 << 29) - 1
    FIRST_RESERVED_FIELD_NUMBER = 19000
    LAST_RESERVED_FIELD_NUMBER = 19999
  
    if _USE_C_DESCRIPTORS:
      _C_DESCRIPTOR_CLASS = _message.FieldDescriptor
  
      def __new__(cls, name, full_name, index, number, type, cpp_type, label,
                  default_value, message_type, enum_type, containing_type,
                  is_extension, extension_scope, options=None,
                  serialized_options=None,
                  has_default_value=True, containing_oneof=None, json_name=None,
                  file=None):  # pylint: disable=redefined-builtin
        _message.Message._CheckCalledFromGeneratedFile()
        if is_extension:
          return _message.default_pool.FindExtensionByName(full_name)
        else:
          return _message.default_pool.FindFieldByName(full_name)
  
    def __init__(self, name, full_name, index, number, type, cpp_type, label,
                 default_value, message_type, enum_type, containing_type,
                 is_extension, extension_scope, options=None,
                 serialized_options=None,
                 has_default_value=True, containing_oneof=None, json_name=None,
                 file=None):  # pylint: disable=redefined-builtin
      """The arguments are as described in the description of FieldDescriptor
      attributes above.
  
      Note that containing_type may be None, and may be set later if necessary
      (to deal with circular references between message types, for example).
      Likewise for extension_scope.
      """
      super(FieldDescriptor, self).__init__(
          options, serialized_options, 'FieldOptions')
      self.name = name
      self.full_name = full_name
      self.file = file
      self._camelcase_name = None
      if json_name is None:
        self.json_name = _ToJsonName(name)
      else:
        self.json_name = json_name
      self.index = index
      self.number = number
      self.type = type
      self.cpp_type = cpp_type
      self.label = label
      self.has_default_value = has_default_value
      self.default_value = default_value
      self.containing_type = containing_type
      self.message_type = message_type
      self.enum_type = enum_type
      self.is_extension = is_extension
      self.extension_scope = extension_scope
      self.containing_oneof = containing_oneof
      if api_implementation.Type() == 'cpp':
        if is_extension:
          self._cdescriptor = _message.default_pool.FindExtensionByName(full_name)
        else:
          self._cdescriptor = _message.default_pool.FindFieldByName(full_name)
      else:
        self._cdescriptor = None
  
    @property
    def camelcase_name(self):
      if self._camelcase_name is None:
        self._camelcase_name = _ToCamelCase(self.name)
      return self._camelcase_name
  
    @staticmethod
    def ProtoTypeToCppProtoType(proto_type):
      """Converts from a Python proto type to a C++ Proto Type.
  
      The Python ProtocolBuffer classes specify both the 'Python' datatype and the
      'C++' datatype - and they're not the same. This helper method should
      translate from one to another.
  
      Args:
        proto_type: the Python proto type (descriptor.FieldDescriptor.TYPE_*)
      Returns:
        descriptor.FieldDescriptor.CPPTYPE_*, the C++ type.
      Raises:
        TypeTransformationError: when the Python proto type isn't known.
      """
      try:
        return FieldDescriptor._PYTHON_TO_CPP_PROTO_TYPE_MAP[proto_type]
      except KeyError:
        raise TypeTransformationError('Unknown proto_type: %s' % proto_type)
  
  
  class EnumDescriptor(_NestedDescriptorBase):
  
    """Descriptor for an enum defined in a .proto file.
  
    An EnumDescriptor instance has the following attributes:
  
      name: (str) Name of the enum type.
      full_name: (str) Full name of the type, including package name
        and any enclosing type(s).
  
      values: (list of EnumValueDescriptors) List of the values
        in this enum.
      values_by_name: (dict str -> EnumValueDescriptor) Same as |values|,
        but indexed by the "name" field of each EnumValueDescriptor.
      values_by_number: (dict int -> EnumValueDescriptor) Same as |values|,
        but indexed by the "number" field of each EnumValueDescriptor.
      containing_type: (Descriptor) Descriptor of the immediate containing
        type of this enum, or None if this is an enum defined at the
        top level in a .proto file.  Set by Descriptor's constructor
        if we're passed into one.
      file: (FileDescriptor) Reference to file descriptor.
      options: (descriptor_pb2.EnumOptions) Enum options message or
        None to use default enum options.
    """
  
    if _USE_C_DESCRIPTORS:
      _C_DESCRIPTOR_CLASS = _message.EnumDescriptor
  
      def __new__(cls, name, full_name, filename, values,
                  containing_type=None, options=None,
                  serialized_options=None, file=None,  # pylint: disable=redefined-builtin
                  serialized_start=None, serialized_end=None):
        _message.Message._CheckCalledFromGeneratedFile()
        return _message.default_pool.FindEnumTypeByName(full_name)
  
    def __init__(self, name, full_name, filename, values,
                 containing_type=None, options=None,
                 serialized_options=None, file=None,  # pylint: disable=redefined-builtin
                 serialized_start=None, serialized_end=None):
      """Arguments are as described in the attribute description above.
  
      Note that filename is an obsolete argument, that is not used anymore.
      Please use file.name to access this as an attribute.
      """
      super(EnumDescriptor, self).__init__(
          options, 'EnumOptions', name, full_name, file,
          containing_type, serialized_start=serialized_start,
          serialized_end=serialized_end, serialized_options=serialized_options)
  
      self.values = values
      for value in self.values:
        value.type = self
      self.values_by_name = dict((v.name, v) for v in values)
      # Values are reversed to ensure that the first alias is retained.
      self.values_by_number = dict((v.number, v) for v in reversed(values))
  
    def CopyToProto(self, proto):
      """Copies this to a descriptor_pb2.EnumDescriptorProto.
  
      Args:
        proto: An empty descriptor_pb2.EnumDescriptorProto.
      """
      # This function is overridden to give a better doc comment.
      super(EnumDescriptor, self).CopyToProto(proto)
  
  
  class EnumValueDescriptor(DescriptorBase):
  
    """Descriptor for a single value within an enum.
  
      name: (str) Name of this value.
      index: (int) Dense, 0-indexed index giving the order that this
        value appears textually within its enum in the .proto file.
      number: (int) Actual number assigned to this enum value.
      type: (EnumDescriptor) EnumDescriptor to which this value
        belongs.  Set by EnumDescriptor's constructor if we're
        passed into one.
      options: (descriptor_pb2.EnumValueOptions) Enum value options message or
        None to use default enum value options options.
    """
  
    if _USE_C_DESCRIPTORS:
      _C_DESCRIPTOR_CLASS = _message.EnumValueDescriptor
  
      def __new__(cls, name, index, number,
                  type=None,  # pylint: disable=redefined-builtin
                  options=None, serialized_options=None):
        _message.Message._CheckCalledFromGeneratedFile()
        # There is no way we can build a complete EnumValueDescriptor with the
        # given parameters (the name of the Enum is not known, for example).
        # Fortunately generated files just pass it to the EnumDescriptor()
        # constructor, which will ignore it, so returning None is good enough.
        return None
  
    def __init__(self, name, index, number,
                 type=None,  # pylint: disable=redefined-builtin
                 options=None, serialized_options=None):
      """Arguments are as described in the attribute description above."""
      super(EnumValueDescriptor, self).__init__(
          options, serialized_options, 'EnumValueOptions')
      self.name = name
      self.index = index
      self.number = number
      self.type = type
  
  
  class OneofDescriptor(DescriptorBase):
    """Descriptor for a oneof field.
  
      name: (str) Name of the oneof field.
      full_name: (str) Full name of the oneof field, including package name.
      index: (int) 0-based index giving the order of the oneof field inside
        its containing type.
      containing_type: (Descriptor) Descriptor of the protocol message
        type that contains this field.  Set by the Descriptor constructor
        if we're passed into one.
      fields: (list of FieldDescriptor) The list of field descriptors this
        oneof can contain.
    """
  
    if _USE_C_DESCRIPTORS:
      _C_DESCRIPTOR_CLASS = _message.OneofDescriptor
  
      def __new__(
          cls, name, full_name, index, containing_type, fields, options=None,
          serialized_options=None):
        _message.Message._CheckCalledFromGeneratedFile()
        return _message.default_pool.FindOneofByName(full_name)
  
    def __init__(
        self, name, full_name, index, containing_type, fields, options=None,
        serialized_options=None):
      """Arguments are as described in the attribute description above."""
      super(OneofDescriptor, self).__init__(
          options, serialized_options, 'OneofOptions')
      self.name = name
      self.full_name = full_name
      self.index = index
      self.containing_type = containing_type
      self.fields = fields
  
  
  class ServiceDescriptor(_NestedDescriptorBase):
  
    """Descriptor for a service.
  
      name: (str) Name of the service.
      full_name: (str) Full name of the service, including package name.
      index: (int) 0-indexed index giving the order that this services
        definition appears withing the .proto file.
      methods: (list of MethodDescriptor) List of methods provided by this
        service.
      methods_by_name: (dict str -> MethodDescriptor) Same MethodDescriptor
        objects as in |methods_by_name|, but indexed by "name" attribute in each
        MethodDescriptor.
      options: (descriptor_pb2.ServiceOptions) Service options message or
        None to use default service options.
      file: (FileDescriptor) Reference to file info.
    """
  
    if _USE_C_DESCRIPTORS:
      _C_DESCRIPTOR_CLASS = _message.ServiceDescriptor
  
      def __new__(cls, name, full_name, index, methods, options=None,
                  serialized_options=None, file=None,  # pylint: disable=redefined-builtin
                  serialized_start=None, serialized_end=None):
        _message.Message._CheckCalledFromGeneratedFile()  # pylint: disable=protected-access
        return _message.default_pool.FindServiceByName(full_name)
  
    def __init__(self, name, full_name, index, methods, options=None,
                 serialized_options=None, file=None,  # pylint: disable=redefined-builtin
                 serialized_start=None, serialized_end=None):
      super(ServiceDescriptor, self).__init__(
          options, 'ServiceOptions', name, full_name, file,
          None, serialized_start=serialized_start,
          serialized_end=serialized_end, serialized_options=serialized_options)
      self.index = index
      self.methods = methods
      self.methods_by_name = dict((m.name, m) for m in methods)
      # Set the containing service for each method in this service.
      for method in self.methods:
        method.containing_service = self
  
    def FindMethodByName(self, name):
      """Searches for the specified method, and returns its descriptor."""
      return self.methods_by_name.get(name, None)
  
    def CopyToProto(self, proto):
      """Copies this to a descriptor_pb2.ServiceDescriptorProto.
  
      Args:
        proto: An empty descriptor_pb2.ServiceDescriptorProto.
      """
      # This function is overridden to give a better doc comment.
      super(ServiceDescriptor, self).CopyToProto(proto)
  
  
  class MethodDescriptor(DescriptorBase):
  
    """Descriptor for a method in a service.
  
    name: (str) Name of the method within the service.
    full_name: (str) Full name of method.
    index: (int) 0-indexed index of the method inside the service.
    containing_service: (ServiceDescriptor) The service that contains this
      method.
    input_type: The descriptor of the message that this method accepts.
    output_type: The descriptor of the message that this method returns.
    options: (descriptor_pb2.MethodOptions) Method options message or
      None to use default method options.
    """
  
    if _USE_C_DESCRIPTORS:
      _C_DESCRIPTOR_CLASS = _message.MethodDescriptor
  
      def __new__(cls, name, full_name, index, containing_service,
                  input_type, output_type, options=None, serialized_options=None):
        _message.Message._CheckCalledFromGeneratedFile()  # pylint: disable=protected-access
        return _message.default_pool.FindMethodByName(full_name)
  
    def __init__(self, name, full_name, index, containing_service,
                 input_type, output_type, options=None, serialized_options=None):
      """The arguments are as described in the description of MethodDescriptor
      attributes above.
  
      Note that containing_service may be None, and may be set later if necessary.
      """
      super(MethodDescriptor, self).__init__(
          options, serialized_options, 'MethodOptions')
      self.name = name
      self.full_name = full_name
      self.index = index
      self.containing_service = containing_service
      self.input_type = input_type
      self.output_type = output_type
  
  
  class FileDescriptor(DescriptorBase):
    """Descriptor for a file. Mimics the descriptor_pb2.FileDescriptorProto.
  
    Note that enum_types_by_name, extensions_by_name, and dependencies
    fields are only set by the message_factory module, and not by the
    generated proto code.
  
    name: name of file, relative to root of source tree.
    package: name of the package
    syntax: string indicating syntax of the file (can be "proto2" or "proto3")
    serialized_pb: (str) Byte string of serialized
      descriptor_pb2.FileDescriptorProto.
    dependencies: List of other FileDescriptors this FileDescriptor depends on.
    public_dependencies: A list of FileDescriptors, subset of the dependencies
      above, which were declared as "public".
    message_types_by_name: Dict of message names and their descriptors.
    enum_types_by_name: Dict of enum names and their descriptors.
    extensions_by_name: Dict of extension names and their descriptors.
    services_by_name: Dict of services names and their descriptors.
    pool: the DescriptorPool this descriptor belongs to.  When not passed to the
      constructor, the global default pool is used.
    """
  
    if _USE_C_DESCRIPTORS:
      _C_DESCRIPTOR_CLASS = _message.FileDescriptor
  
      def __new__(cls, name, package, options=None,
                  serialized_options=None, serialized_pb=None,
                  dependencies=None, public_dependencies=None,
                  syntax=None, pool=None):
        # FileDescriptor() is called from various places, not only from generated
        # files, to register dynamic proto files and messages.
        if serialized_pb:
          # TODO(amauryfa): use the pool passed as argument. This will work only
          # for C++-implemented DescriptorPools.
          return _message.default_pool.AddSerializedFile(serialized_pb)
        else:
          return super(FileDescriptor, cls).__new__(cls)
  
    def __init__(self, name, package, options=None,
                 serialized_options=None, serialized_pb=None,
                 dependencies=None, public_dependencies=None,
                 syntax=None, pool=None):
      """Constructor."""
      super(FileDescriptor, self).__init__(
          options, serialized_options, 'FileOptions')
  
      if pool is None:
        from google.protobuf import descriptor_pool
        pool = descriptor_pool.Default()
      self.pool = pool
      self.message_types_by_name = {}
      self.name = name
      self.package = package
      self.syntax = syntax or "proto2"
      self.serialized_pb = serialized_pb
  
      self.enum_types_by_name = {}
      self.extensions_by_name = {}
      self.services_by_name = {}
      self.dependencies = (dependencies or [])
      self.public_dependencies = (public_dependencies or [])
  
      if (api_implementation.Type() == 'cpp' and
          self.serialized_pb is not None):
        _message.default_pool.AddSerializedFile(self.serialized_pb)
  
    def CopyToProto(self, proto):
      """Copies this to a descriptor_pb2.FileDescriptorProto.
  
      Args:
        proto: An empty descriptor_pb2.FileDescriptorProto.
      """
      proto.ParseFromString(self.serialized_pb)
  
  
  def _ParseOptions(message, string):
    """Parses serialized options.
  
    This helper function is used to parse serialized options in generated
    proto2 files. It must not be used outside proto2.
    """
    message.ParseFromString(string)
    return message
  
  
  def _ToCamelCase(name):
    """Converts name to camel-case and returns it."""
    capitalize_next = False
    result = []
  
    for c in name:
      if c == '_':
        if result:
          capitalize_next = True
      elif capitalize_next:
        result.append(c.upper())
        capitalize_next = False
      else:
        result += c
  
    # Lower-case the first letter.
    if result and result[0].isupper():
      result[0] = result[0].lower()
    return ''.join(result)
  
  
  def _OptionsOrNone(descriptor_proto):
    """Returns the value of the field `options`, or None if it is not set."""
    if descriptor_proto.HasField('options'):
      return descriptor_proto.options
    else:
      return None
  
  
  def _ToJsonName(name):
    """Converts name to Json name and returns it."""
    capitalize_next = False
    result = []
  
    for c in name:
      if c == '_':
        capitalize_next = True
      elif capitalize_next:
        result.append(c.upper())
        capitalize_next = False
      else:
        result += c
  
    return ''.join(result)
  
  
  def MakeDescriptor(desc_proto, package='', build_file_if_cpp=True,
                     syntax=None):
    """Make a protobuf Descriptor given a DescriptorProto protobuf.
  
    Handles nested descriptors. Note that this is limited to the scope of defining
    a message inside of another message. Composite fields can currently only be
    resolved if the message is defined in the same scope as the field.
  
    Args:
      desc_proto: The descriptor_pb2.DescriptorProto protobuf message.
      package: Optional package name for the new message Descriptor (string).
      build_file_if_cpp: Update the C++ descriptor pool if api matches.
                         Set to False on recursion, so no duplicates are created.
      syntax: The syntax/semantics that should be used.  Set to "proto3" to get
              proto3 field presence semantics.
    Returns:
      A Descriptor for protobuf messages.
    """
    if api_implementation.Type() == 'cpp' and build_file_if_cpp:
      # The C++ implementation requires all descriptors to be backed by the same
      # definition in the C++ descriptor pool. To do this, we build a
      # FileDescriptorProto with the same definition as this descriptor and build
      # it into the pool.
      from google.protobuf import descriptor_pb2
      file_descriptor_proto = descriptor_pb2.FileDescriptorProto()
      file_descriptor_proto.message_type.add().MergeFrom(desc_proto)
  
      # Generate a random name for this proto file to prevent conflicts with any
      # imported ones. We need to specify a file name so the descriptor pool
      # accepts our FileDescriptorProto, but it is not important what that file
      # name is actually set to.
      proto_name = binascii.hexlify(os.urandom(16)).decode('ascii')
  
      if package:
        file_descriptor_proto.name = os.path.join(package.replace('.', '/'),
                                                  proto_name + '.proto')
        file_descriptor_proto.package = package
      else:
        file_descriptor_proto.name = proto_name + '.proto'
  
      _message.default_pool.Add(file_descriptor_proto)
      result = _message.default_pool.FindFileByName(file_descriptor_proto.name)
  
      if _USE_C_DESCRIPTORS:
        return result.message_types_by_name[desc_proto.name]
  
    full_message_name = [desc_proto.name]
    if package: full_message_name.insert(0, package)
  
    # Create Descriptors for enum types
    enum_types = {}
    for enum_proto in desc_proto.enum_type:
      full_name = '.'.join(full_message_name + [enum_proto.name])
      enum_desc = EnumDescriptor(
        enum_proto.name, full_name, None, [
            EnumValueDescriptor(enum_val.name, ii, enum_val.number)
            for ii, enum_val in enumerate(enum_proto.value)])
      enum_types[full_name] = enum_desc
  
    # Create Descriptors for nested types
    nested_types = {}
    for nested_proto in desc_proto.nested_type:
      full_name = '.'.join(full_message_name + [nested_proto.name])
      # Nested types are just those defined inside of the message, not all types
      # used by fields in the message, so no loops are possible here.
      nested_desc = MakeDescriptor(nested_proto,
                                   package='.'.join(full_message_name),
                                   build_file_if_cpp=False,
                                   syntax=syntax)
      nested_types[full_name] = nested_desc
  
    fields = []
    for field_proto in desc_proto.field:
      full_name = '.'.join(full_message_name + [field_proto.name])
      enum_desc = None
      nested_desc = None
      if field_proto.json_name:
        json_name = field_proto.json_name
      else:
        json_name = None
      if field_proto.HasField('type_name'):
        type_name = field_proto.type_name
        full_type_name = '.'.join(full_message_name +
                                  [type_name[type_name.rfind('.')+1:]])
        if full_type_name in nested_types:
          nested_desc = nested_types[full_type_name]
        elif full_type_name in enum_types:
          enum_desc = enum_types[full_type_name]
        # Else type_name references a non-local type, which isn't implemented
      field = FieldDescriptor(
          field_proto.name, full_name, field_proto.number - 1,
          field_proto.number, field_proto.type,
          FieldDescriptor.ProtoTypeToCppProtoType(field_proto.type),
          field_proto.label, None, nested_desc, enum_desc, None, False, None,
          options=_OptionsOrNone(field_proto), has_default_value=False,
          json_name=json_name)
      fields.append(field)
  
    desc_name = '.'.join(full_message_name)
    return Descriptor(desc_proto.name, desc_name, None, None, fields,
                      list(nested_types.values()), list(enum_types.values()), [],
                      options=_OptionsOrNone(desc_proto))
  