from __future__ import absolute_import, division, unicode_literals
import sys
from types import ModuleType
from six import text_type
try:
import xml.etree.cElementTree as default_etree
except ImportError:
import xml.etree.ElementTree as default_etree
__all__ = ["default_etree", "MethodDispatcher", "isSurrogatePair",
"surrogatePairToCodepoint", "moduleFactoryFactory",
"supports_lone_surrogates", "PY27"]
PY27 = sys.version_info[0] == 2 and sys.version_info[1] >= 7
# Platforms not supporting lone surrogates (\uD800-\uDFFF) should be
# caught by the below test. In general this would be any platform
# using UTF-16 as its encoding of unicode strings, such as
# Jython. This is because UTF-16 itself is based on the use of such
# surrogates, and there is no mechanism to further escape such
# escapes.
try:
_x = eval('"\\uD800"') # pylint:disable=eval-used
if not isinstance(_x, text_type):
# We need this with u"" because of http://bugs.jython.org/issue2039
_x = eval('u"\\uD800"') # pylint:disable=eval-used
assert isinstance(_x, text_type)
except: # pylint:disable=bare-except
supports_lone_surrogates = False
else:
supports_lone_surrogates = True
class MethodDispatcher(dict):
"""Dict with 2 special properties:
On initiation, keys that are lists, sets or tuples are converted to
multiple keys so accessing any one of the items in the original
list-like object returns the matching value
md = MethodDispatcher({("foo", "bar"):"baz"})
md["foo"] == "baz"
A default value which can be set through the default attribute.
"""
def __init__(self, items=()):
# Using _dictEntries instead of directly assigning to self is about
# twice as fast. Please do careful performance testing before changing
# anything here.
_dictEntries = []
for name, value in items:
if isinstance(name, (list, tuple, frozenset, set)):
for item in name:
_dictEntries.append((item, value))
else:
_dictEntries.append((name, value))
dict.__init__(self, _dictEntries)
assert len(self) == len(_dictEntries)
self.default = None
def __getitem__(self, key):
return dict.get(self, key, self.default)
# Some utility functions to deal with weirdness around UCS2 vs UCS4
# python builds
def isSurrogatePair(data):
return (len(data) == 2 and
ord(data[0]) >= 0xD800 and ord(data[0]) <= 0xDBFF and
ord(data[1]) >= 0xDC00 and ord(data[1]) <= 0xDFFF)
def surrogatePairToCodepoint(data):
char_val = (0x10000 + (ord(data[0]) - 0xD800) * 0x400 +
(ord(data[1]) - 0xDC00))
return char_val
# Module Factory Factory (no, this isn't Java, I know)
# Here to stop this being duplicated all over the place.
def moduleFactoryFactory(factory):
moduleCache = {}
def moduleFactory(baseModule, *args, **kwargs):
if isinstance(ModuleType.__name__, type("")):
name = "_%s_factory" % baseModule.__name__
else:
name = b"_%s_factory" % baseModule.__name__
kwargs_tuple = tuple(kwargs.items())
try:
return moduleCache[name][args][kwargs_tuple]
except KeyError:
mod = ModuleType(name)
objs = factory(baseModule, *args, **kwargs)
mod.__dict__.update(objs)
if "name" not in moduleCache:
moduleCache[name] = {}
if "args" not in moduleCache[name]:
moduleCache[name][args] = {}
if "kwargs" not in moduleCache[name][args]:
moduleCache[name][args][kwargs_tuple] = {}
moduleCache[name][args][kwargs_tuple] = mod
return mod
return moduleFactory
def memoize(func):
cache = {}
def wrapped(*args, **kwargs):
key = (tuple(args), tuple(kwargs.items()))
if key not in cache:
cache[key] = func(*args, **kwargs)
return cache[key]
return wrapped
