representer.py 文件源码

def represent_object(self, data):
        # We use __reduce__ API to save the data. data.__reduce__ returns
        # a tuple of length 2-5:
        #   (function, args, state, listitems, dictitems)

        # For reconstructing, we calls function(*args), then set its state,
        # listitems, and dictitems if they are not None.

        # A special case is when function.__name__ == '__newobj__'. In this
        # case we create the object with args[0].__new__(*args).

        # Another special case is when __reduce__ returns a string - we don't
        # support it.

        # We produce a !!python/object, !!python/object/new or
        # !!python/object/apply node.

        cls = type(data)
        if cls in copy_reg.dispatch_table:
            reduce = copy_reg.dispatch_table[cls](data)
        elif hasattr(data, '__reduce_ex__'):
            reduce = data.__reduce_ex__(2)
        elif hasattr(data, '__reduce__'):
            reduce = data.__reduce__()
        else:
            raise RepresenterError("cannot represent object: %r" % data)
        reduce = (list(reduce)+[None]*5)[:5]
        function, args, state, listitems, dictitems = reduce
        args = list(args)
        if state is None:
            state = {}
        if listitems is not None:
            listitems = list(listitems)
        if dictitems is not None:
            dictitems = dict(dictitems)
        if function.__name__ == '__newobj__':
            function = args[0]
            args = args[1:]
            tag = u'tag:yaml.org,2002:python/object/new:'
            newobj = True
        else:
            tag = u'tag:yaml.org,2002:python/object/apply:'
            newobj = False
        function_name = u'%s.%s' % (function.__module__, function.__name__)
        if not args and not listitems and not dictitems \
                and isinstance(state, dict) and newobj:
            return self.represent_mapping(
                    u'tag:yaml.org,2002:python/object:'+function_name, state)
        if not listitems and not dictitems  \
                and isinstance(state, dict) and not state:
            return self.represent_sequence(tag+function_name, args)
        value = {}
        if args:
            value['args'] = args
        if state or not isinstance(state, dict):
            value['state'] = state
        if listitems:
            value['listitems'] = listitems
        if dictitems:
            value['dictitems'] = dictitems
        return self.represent_mapping(tag+function_name, value)