symbol_database

class SymbolDatabase(message_factory.MessageFactory):
  """A database of Python generated symbols."""

  def RegisterMessage(self, message):
    """Registers the given message type in the local database.

    Calls to GetSymbol() and GetMessages() will return messages registered here.

    Args:
      message: A :class:`google.protobuf.message.Message` subclass (or
        instance); its descriptor will be registered.

    Returns:
      The provided message.
    """

    desc = message.DESCRIPTOR
    self._classes[desc] = message
    self.RegisterMessageDescriptor(desc)
    return message

  def RegisterMessageDescriptor(self, message_descriptor):
    """Registers the given message descriptor in the local database.

    Args:
      message_descriptor (Descriptor): the message descriptor to add.
    """
    if api_implementation.Type() == 'python':
      # pylint: disable=protected-access
      self.pool._AddDescriptor(message_descriptor)

  def RegisterEnumDescriptor(self, enum_descriptor):
    """Registers the given enum descriptor in the local database.

    Args:
      enum_descriptor (EnumDescriptor): The enum descriptor to register.

    Returns:
      EnumDescriptor: The provided descriptor.
    """
    if api_implementation.Type() == 'python':
      # pylint: disable=protected-access
      self.pool._AddEnumDescriptor(enum_descriptor)
    return enum_descriptor

  def RegisterServiceDescriptor(self, service_descriptor):
    """Registers the given service descriptor in the local database.

    Args:
      service_descriptor (ServiceDescriptor): the service descriptor to
        register.
    """
    if api_implementation.Type() == 'python':
      # pylint: disable=protected-access
      self.pool._AddServiceDescriptor(service_descriptor)

  def RegisterFileDescriptor(self, file_descriptor):
    """Registers the given file descriptor in the local database.

    Args:
      file_descriptor (FileDescriptor): The file descriptor to register.
    """
    if api_implementation.Type() == 'python':
      # pylint: disable=protected-access
      self.pool._InternalAddFileDescriptor(file_descriptor)

  def GetSymbol(self, symbol):
    """Tries to find a symbol in the local database.

    Currently, this method only returns message.Message instances, however, if
    may be extended in future to support other symbol types.

    Args:
      symbol (str): a protocol buffer symbol.

    Returns:
      A Python class corresponding to the symbol.

    Raises:
      KeyError: if the symbol could not be found.
    """

    return self._classes[self.pool.FindMessageTypeByName(symbol)]

  def GetMessages(self, files):
    # TODO(amauryfa): Fix the differences with MessageFactory.
    """Gets all registered messages from a specified file.

    Only messages already created and registered will be returned; (this is the
    case for imported _pb2 modules)
    But unlike MessageFactory, this version also returns already defined nested
    messages, but does not register any message extensions.

    Args:
      files (list[str]): The file names to extract messages from.

    Returns:
      A dictionary mapping proto names to the message classes.

    Raises:
      KeyError: if a file could not be found.
    """

    def _GetAllMessages(desc):
      """Walk a message Descriptor and recursively yields all message names."""
      yield desc
      for msg_desc in desc.nested_types:
        for nested_desc in _GetAllMessages(msg_desc):
          yield nested_desc

    result = {}
    for file_name in files:
      file_desc = self.pool.FindFileByName(file_name)
      for msg_desc in file_desc.message_types_by_name.values():
        for desc in _GetAllMessages(msg_desc):
          try:
            result[desc.full_name] = self._classes[desc]
          except KeyError:
            # This descriptor has no registered class, skip it.
            pass
    return result