JezK
Edit File: _utils.py
from __future__ import absolute_import, division, unicode_literals from types import ModuleType try: from collections.abc import Mapping except ImportError: from collections import Mapping from six import text_type, PY3 if PY3: import xml.etree.ElementTree as default_etree else: 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"] # 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 Exception: 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=()): _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) def __get__(self, instance, owner=None): return BoundMethodDispatcher(instance, self) class BoundMethodDispatcher(Mapping): """Wraps a MethodDispatcher, binding its return values to `instance`""" def __init__(self, instance, dispatcher): self.instance = instance self.dispatcher = dispatcher def __getitem__(self, key): # see https://docs.python.org/3/reference/datamodel.html#object.__get__ # on a function, __get__ is used to bind a function to an instance as a bound method return self.dispatcher[key].__get__(self.instance) def get(self, key, default): if key in self.dispatcher: return self[key] else: return default def __iter__(self): return iter(self.dispatcher) def __len__(self): return len(self.dispatcher) def __contains__(self, key): return key in self.dispatcher # 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