"""passlib.utils.compat - python 2/3 compatibility helpers"""
#=============================================================================
# figure out what we're running
#=============================================================================
#------------------------------------------------------------------------
# python version
#------------------------------------------------------------------------
import sys
PY2 = sys.version_info < (3,0)
PY3 = sys.version_info >= (3,0)
# make sure it's not an unsupported version, even if we somehow got this far
if sys.version_info < (2,6) or (3,0) <= sys.version_info < (3,2):
raise RuntimeError("Passlib requires Python 2.6, 2.7, or >= 3.2 (as of passlib 1.7)")
PY26 = sys.version_info < (2,7)
#------------------------------------------------------------------------
# python implementation
#------------------------------------------------------------------------
JYTHON = sys.platform.startswith('java')
PYPY = hasattr(sys, "pypy_version_info")
if PYPY and sys.pypy_version_info < (2,0):
raise RuntimeError("passlib requires pypy >= 2.0 (as of passlib 1.7)")
# e.g. '2.7.7\n[Pyston 0.5.1]'
PYSTON = "Pyston" in sys.version
#=============================================================================
# common imports
#=============================================================================
import logging; log = logging.getLogger(__name__)
if PY3:
import builtins
else:
import __builtin__ as builtins
def add_doc(obj, doc):
"""add docstring to an object"""
obj.__doc__ = doc
#=============================================================================
# the default exported vars
#=============================================================================
__all__ = [
# python versions
'PY2', 'PY3', 'PY26',
# io
'BytesIO', 'StringIO', 'NativeStringIO', 'SafeConfigParser',
'print_',
# type detection
## 'is_mapping',
'int_types',
'num_types',
'unicode_or_bytes_types',
'native_string_types',
# unicode/bytes types & helpers
'u',
'unicode',
'uascii_to_str', 'bascii_to_str',
'str_to_uascii', 'str_to_bascii',
'join_unicode', 'join_bytes',
'join_byte_values', 'join_byte_elems',
'byte_elem_value',
'iter_byte_values',
# iteration helpers
'irange', #'lrange',
'imap', 'lmap',
'iteritems', 'itervalues',
'next',
# collections
'OrderedDict',
# introspection
'get_method_function', 'add_doc',
]
# begin accumulating mapping of lazy-loaded attrs,
# 'merged' into module at bottom
_lazy_attrs = dict()
#=============================================================================
# unicode & bytes types
#=============================================================================
if PY3:
unicode = str
# TODO: once we drop python 3.2 support, can use u'' again!
def u(s):
assert isinstance(s, str)
return s
unicode_or_bytes_types = (str, bytes)
native_string_types = (unicode,)
else:
unicode = builtins.unicode
def u(s):
assert isinstance(s, str)
return s.decode("unicode_escape")
unicode_or_bytes_types = (basestring,)
native_string_types = (basestring,)
# shorter preferred aliases
unicode_or_bytes = unicode_or_bytes_types
unicode_or_str = native_string_types
# unicode -- unicode type, regardless of python version
# bytes -- bytes type, regardless of python version
# unicode_or_bytes_types -- types that text can occur in, whether encoded or not
# native_string_types -- types that native python strings (dict keys etc) can occur in.
#=============================================================================
# unicode & bytes helpers
#=============================================================================
# function to join list of unicode strings
join_unicode = u('').join
# function to join list of byte strings
join_bytes = b''.join
if PY3:
def uascii_to_str(s):
assert isinstance(s, unicode)
return s
def bascii_to_str(s):
assert isinstance(s, bytes)
return s.decode("ascii")
def str_to_uascii(s):
assert isinstance(s, str)
return s
def str_to_bascii(s):
assert isinstance(s, str)
return s.encode("ascii")
join_byte_values = join_byte_elems = bytes
def byte_elem_value(elem):
assert isinstance(elem, int)
return elem
def iter_byte_values(s):
assert isinstance(s, bytes)
return s
def iter_byte_chars(s):
assert isinstance(s, bytes)
# FIXME: there has to be a better way to do this
return (bytes([c]) for c in s)
else:
def uascii_to_str(s):
assert isinstance(s, unicode)
return s.encode("ascii")
def bascii_to_str(s):
assert isinstance(s, bytes)
return s
def str_to_uascii(s):
assert isinstance(s, str)
return s.decode("ascii")
def str_to_bascii(s):
assert isinstance(s, str)
return s
def join_byte_values(values):
return join_bytes(chr(v) for v in values)
join_byte_elems = join_bytes
byte_elem_value = ord
def iter_byte_values(s):
assert isinstance(s, bytes)
return (ord(c) for c in s)
def iter_byte_chars(s):
assert isinstance(s, bytes)
return s
add_doc(uascii_to_str, "helper to convert ascii unicode -> native str")
add_doc(bascii_to_str, "helper to convert ascii bytes -> native str")
add_doc(str_to_uascii, "helper to convert ascii native str -> unicode")
add_doc(str_to_bascii, "helper to convert ascii native str -> bytes")
# join_byte_values -- function to convert list of ordinal integers to byte string.
# join_byte_elems -- function to convert list of byte elements to byte string;
# i.e. what's returned by ``b('a')[0]``...
# this is b('a') under PY2, but 97 under PY3.
# byte_elem_value -- function to convert byte element to integer -- a noop under PY3
add_doc(iter_byte_values, "iterate over byte string as sequence of ints 0-255")
add_doc(iter_byte_chars, "iterate over byte string as sequence of 1-byte strings")
#=============================================================================
# numeric
#=============================================================================
if PY3:
int_types = (int,)
num_types = (int, float)
else:
int_types = (int, long)
num_types = (int, long, float)
#=============================================================================
# iteration helpers
#
# irange - range iterable / view (xrange under py2, range under py3)
# lrange - range list (range under py2, list(range()) under py3)
#
# imap - map to iterator
# lmap - map to list
#=============================================================================
if PY3:
irange = range
##def lrange(*a,**k):
## return list(range(*a,**k))
def lmap(*a, **k):
return list(map(*a,**k))
imap = map
def iteritems(d):
return d.items()
def itervalues(d):
return d.values()
def nextgetter(obj):
return obj.__next__
izip = zip
else:
irange = xrange
##lrange = range
lmap = map
from itertools import imap, izip
def iteritems(d):
return d.iteritems()
def itervalues(d):
return d.itervalues()
def nextgetter(obj):
return obj.next
add_doc(nextgetter, "return function that yields successive values from iterable")
#=============================================================================
# typing
#=============================================================================
##def is_mapping(obj):
## # non-exhaustive check, enough to distinguish from lists, etc
## return hasattr(obj, "items")
#=============================================================================
# introspection
#=============================================================================
if PY3:
method_function_attr = "__func__"
else:
method_function_attr = "im_func"
def get_method_function(func):
"""given (potential) method, return underlying function"""
return getattr(func, method_function_attr, func)
def get_unbound_method_function(func):
"""given unbound method, return underlying function"""
return func if PY3 else func.__func__
def suppress_cause(exc):
"""
backward compat hack to suppress exception cause in python3.3+
one python < 3.3 support is dropped, can replace all uses with "raise exc from None"
"""
exc.__cause__ = None
return exc
#=============================================================================
# input/output
#=============================================================================
if PY3:
_lazy_attrs = dict(
BytesIO="io.BytesIO",
UnicodeIO="io.StringIO",
NativeStringIO="io.StringIO",
SafeConfigParser="configparser.ConfigParser",
)
print_ = getattr(builtins, "print")
else:
_lazy_attrs = dict(
BytesIO="cStringIO.StringIO",
UnicodeIO="StringIO.StringIO",
NativeStringIO="cStringIO.StringIO",
SafeConfigParser="ConfigParser.SafeConfigParser",
)
def print_(*args, **kwds):
"""The new-style print function."""
# extract kwd args
fp = kwds.pop("file", sys.stdout)
sep = kwds.pop("sep", None)
end = kwds.pop("end", None)
if kwds:
raise TypeError("invalid keyword arguments")
# short-circuit if no target
if fp is None:
return
# use unicode or bytes ?
want_unicode = isinstance(sep, unicode) or isinstance(end, unicode) or \
any(isinstance(arg, unicode) for arg in args)
# pick default end sequence
if end is None:
end = u("\n") if want_unicode else "\n"
elif not isinstance(end, unicode_or_bytes_types):
raise TypeError("end must be None or a string")
# pick default separator
if sep is None:
sep = u(" ") if want_unicode else " "
elif not isinstance(sep, unicode_or_bytes_types):
raise TypeError("sep must be None or a string")
# write to buffer
first = True
write = fp.write
for arg in args:
if first:
first = False
else:
write(sep)
if not isinstance(arg, basestring):
arg = str(arg)
write(arg)
write(end)
#=============================================================================
# collections
#=============================================================================
if PY26:
_lazy_attrs['OrderedDict'] = 'passlib.utils.compat._ordered_dict.OrderedDict'
else:
_lazy_attrs['OrderedDict'] = 'collections.OrderedDict'
#=============================================================================
# lazy overlay module
#=============================================================================
from types import ModuleType
def _import_object(source):
"""helper to import object from module; accept format `path.to.object`"""
modname, modattr = source.rsplit(".",1)
mod = __import__(modname, fromlist=[modattr], level=0)
return getattr(mod, modattr)
class _LazyOverlayModule(ModuleType):
"""proxy module which overlays original module,
and lazily imports specified attributes.
this is mainly used to prevent importing of resources
that are only needed by certain password hashes,
yet allow them to be imported from a single location.
used by :mod:`passlib.utils`, :mod:`passlib.crypto`,
and :mod:`passlib.utils.compat`.
"""
@classmethod
def replace_module(cls, name, attrmap):
orig = sys.modules[name]
self = cls(name, attrmap, orig)
sys.modules[name] = self
return self
def __init__(self, name, attrmap, proxy=None):
ModuleType.__init__(self, name)
self.__attrmap = attrmap
self.__proxy = proxy
self.__log = logging.getLogger(name)
def __getattr__(self, attr):
proxy = self.__proxy
if proxy and hasattr(proxy, attr):
return getattr(proxy, attr)
attrmap = self.__attrmap
if attr in attrmap:
source = attrmap[attr]
if callable(source):
value = source()
else:
value = _import_object(source)
setattr(self, attr, value)
self.__log.debug("loaded lazy attr %r: %r", attr, value)
return value
raise AttributeError("'module' object has no attribute '%s'" % (attr,))
def __repr__(self):
proxy = self.__proxy
if proxy:
return repr(proxy)
else:
return ModuleType.__repr__(self)
def __dir__(self):
attrs = set(dir(self.__class__))
attrs.update(self.__dict__)
attrs.update(self.__attrmap)
proxy = self.__proxy
if proxy is not None:
attrs.update(dir(proxy))
return list(attrs)
# replace this module with overlay that will lazily import attributes.
_LazyOverlayModule.replace_module(__name__, _lazy_attrs)
#=============================================================================
# eof
#=============================================================================