9.8
  $   ˆl–Ðz¾”d*hŠm@·q—îå1hßÂ„­²ßÁÀ¿ ?÷     # -*- coding: utf-8 -*-
"""A sandbox layer that ensures unsafe operations cannot be performed.
Useful when the template itself comes from an untrusted source.
"""
import operator
import types
import warnings
from collections import deque
from functools import update_wrapper
from string import Formatter

from markupsafe import EscapeFormatter
from markupsafe import Markup

from ._compat import abc
from ._compat import PY2
from ._compat import range_type
from ._compat import string_types
from .environment import Environment
from .exceptions import SecurityError

#: maximum number of items a range may produce
MAX_RANGE = 100000

#: attributes of function objects that are considered unsafe.
if PY2:
    UNSAFE_FUNCTION_ATTRIBUTES = {
        "func_closure",
        "func_code",
        "func_dict",
        "func_defaults",
        "func_globals",
    }
else:
    # On versions > python 2 the special attributes on functions are gone,
    # but they remain on methods and generators for whatever reason.
    UNSAFE_FUNCTION_ATTRIBUTES = set()

#: unsafe method attributes.  function attributes are unsafe for methods too
UNSAFE_METHOD_ATTRIBUTES = {"im_class", "im_func", "im_self"}

#: unsafe generator attributes.
UNSAFE_GENERATOR_ATTRIBUTES = {"gi_frame", "gi_code"}

#: unsafe attributes on coroutines
UNSAFE_COROUTINE_ATTRIBUTES = {"cr_frame", "cr_code"}

#: unsafe attributes on async generators
UNSAFE_ASYNC_GENERATOR_ATTRIBUTES = {"ag_code", "ag_frame"}

# make sure we don't warn in python 2.6 about stuff we don't care about
warnings.filterwarnings(
    "ignore", "the sets module", DeprecationWarning, module=__name__
)

_mutable_set_types = (set,)
_mutable_mapping_types = (dict,)
_mutable_sequence_types = (list,)

# on python 2.x we can register the user collection types
try:
    from UserDict import UserDict, DictMixin
    from UserList import UserList

    _mutable_mapping_types += (UserDict, DictMixin)
    _mutable_set_types += (UserList,)
except ImportError:
    pass

# if sets is still available, register the mutable set from there as well
try:
    from sets import Set

    _mutable_set_types += (Set,)
except ImportError:
    pass

#: register Python 2.6 abstract base classes
_mutable_set_types += (abc.MutableSet,)
_mutable_mapping_types += (abc.MutableMapping,)
_mutable_sequence_types += (abc.MutableSequence,)

_mutable_spec = (
    (
        _mutable_set_types,
        frozenset(
            [
                "add",
                "clear",
                "difference_update",
                "discard",
                "pop",
                "remove",
                "symmetric_difference_update",
                "update",
            ]
        ),
    ),
    (
        _mutable_mapping_types,
        frozenset(["clear", "pop", "popitem", "setdefault", "update"]),
    ),
    (
        _mutable_sequence_types,
        frozenset(["append", "reverse", "insert", "sort", "extend", "remove"]),
    ),
    (
        deque,
        frozenset(
            [
                "append",
                "appendleft",
                "clear",
                "extend",
                "extendleft",
                "pop",
                "popleft",
                "remove",
                "rotate",
            ]
        ),
    ),
)


class _MagicFormatMapping(abc.Mapping):
    """This class implements a dummy wrapper to fix a bug in the Python
    standard library for string formatting.

    See https://bugs.python.org/issue13598 for information about why
    this is necessary.
    """

    def __init__(self, args, kwargs):
        self._args = args
        self._kwargs = kwargs
        self._last_index = 0

    def __getitem__(self, key):
        if key == "":
            idx = self._last_index
            self._last_index += 1
            try:
                return self._args[idx]
            except LookupError:
                pass
            key = str(idx)
        return self._kwargs[key]

    def __iter__(self):
        return iter(self._kwargs)

    def __len__(self):
        r