# -*- coding: utf-8 -*-
"""
 flask._compat
 ~~~~~~~~~~~~~

 Some py2/py3 compatibility support based on a stripped down
 version of six so we don't have to depend on a specific version
 of it.

 :copyright: © 2010 by the Pallets team.
 :license: BSD, see LICENSE for more details.
"""

import sys

PY2 = sys.version_info[0] == 2
_identity = lambda x: x


if not PY2:
 text_type = str
 string_types = (str,)
 integer_types = (int,)

 iterkeys = lambda d: iter(d.keys())
 itervalues = lambda d: iter(d.values())
 iteritems = lambda d: iter(d.items())

 from inspect import getfullargspec as getargspec
 from io import StringIO

 def reraise(tp, value, tb=None):
 if value.__traceback__ is not tb:
 raise value.with_traceback(tb)
 raise value

 implements_to_string = _identity

else:
 text_type = unicode
 string_types = (str, unicode)
 integer_types = (int, long)

 iterkeys = lambda d: d.iterkeys()
 itervalues = lambda d: d.itervalues()
 iteritems = lambda d: d.iteritems()

 from inspect import getargspec
 from cStringIO import StringIO

 exec('def reraise(tp, value, tb=None):\n raise tp, value, tb')

 def implements_to_string(cls):
 cls.__unicode__ = cls.__str__
 cls.__str__ = lambda x: x.__unicode__().encode('utf-8')
 return cls


def with_metaclass(meta, *bases):
 """Create a base class with a metaclass."""
 # This requires a bit of explanation: the basic idea is to make a
 # dummy metaclass for one level of class instantiation that replaces
 # itself with the actual metaclass.
 class metaclass(type):
 def __new__(cls, name, this_bases, d):
 return meta(name, bases, d)
 return type.__new__(metaclass, 'temporary_class', (), {})


# Certain versions of pypy have a bug where clearing the exception stack
# breaks the __exit__ function in a very peculiar way. The second level of
# exception blocks is necessary because pypy seems to forget to check if an
# exception happened until the next bytecode instruction?
#
# Relevant PyPy bugfix commit:
# https://bitbucket.org/pypy/pypy/commits/77ecf91c635a287e88e60d8ddb0f4e9df4003301
# According to ronan on #pypy IRC, it is released in PyPy2 2.3 and later
# versions.
#
# Ubuntu 14.04 has PyPy 2.2.1, which does exhibit this bug.
BROKEN_PYPY_CTXMGR_EXIT = False
if hasattr(sys, 'pypy_version_info'):
 class _Mgr(object):
 def __enter__(self):
 return self
 def __exit__(self, *args):
 if hasattr(sys, 'exc_clear'):
 # Python 3 (PyPy3) doesn't have exc_clear
 sys.exc_clear()
 try:
 try:
 with _Mgr():
 raise AssertionError()
 except:
 raise
 except TypeError:
 BROKEN_PYPY_CTXMGR_EXIT = True
 except AssertionError:
 pass