calibre-web/vendor/flask/_compat.py

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# -*- 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: (c) 2015 by Armin Ronacher.
: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 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 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. This is currently
# true for pypy 2.2.1 for instance. The second level of exception blocks
# is necessary because pypy seems to forget to check if an exception
# happened until the next bytecode instruction?
BROKEN_PYPY_CTXMGR_EXIT = False
if hasattr(sys, 'pypy_version_info'):
class _Mgr(object):
def __enter__(self):
return self
def __exit__(self, *args):
sys.exc_clear()
try:
try:
with _Mgr():
raise AssertionError()
except:
raise
except TypeError:
BROKEN_PYPY_CTXMGR_EXIT = True
except AssertionError:
pass