332 lines
9.5 KiB
Python
332 lines
9.5 KiB
Python
import textwrap
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import warnings
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import inspect
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import uuid
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import collections
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from .compat import callable, exec_, string_types, with_metaclass
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from sqlalchemy.util import format_argspec_plus, update_wrapper
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from sqlalchemy.util.compat import inspect_getfullargspec
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class _ModuleClsMeta(type):
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def __setattr__(cls, key, value):
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super(_ModuleClsMeta, cls).__setattr__(key, value)
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cls._update_module_proxies(key)
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class ModuleClsProxy(with_metaclass(_ModuleClsMeta)):
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"""Create module level proxy functions for the
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methods on a given class.
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The functions will have a compatible signature
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as the methods.
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"""
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_setups = collections.defaultdict(lambda: (set(), []))
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@classmethod
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def _update_module_proxies(cls, name):
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attr_names, modules = cls._setups[cls]
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for globals_, locals_ in modules:
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cls._add_proxied_attribute(name, globals_, locals_, attr_names)
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def _install_proxy(self):
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attr_names, modules = self._setups[self.__class__]
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for globals_, locals_ in modules:
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globals_['_proxy'] = self
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for attr_name in attr_names:
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globals_[attr_name] = getattr(self, attr_name)
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def _remove_proxy(self):
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attr_names, modules = self._setups[self.__class__]
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for globals_, locals_ in modules:
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globals_['_proxy'] = None
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for attr_name in attr_names:
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del globals_[attr_name]
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@classmethod
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def create_module_class_proxy(cls, globals_, locals_):
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attr_names, modules = cls._setups[cls]
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modules.append(
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(globals_, locals_)
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)
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cls._setup_proxy(globals_, locals_, attr_names)
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@classmethod
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def _setup_proxy(cls, globals_, locals_, attr_names):
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for methname in dir(cls):
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cls._add_proxied_attribute(methname, globals_, locals_, attr_names)
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@classmethod
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def _add_proxied_attribute(cls, methname, globals_, locals_, attr_names):
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if not methname.startswith('_'):
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meth = getattr(cls, methname)
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if callable(meth):
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locals_[methname] = cls._create_method_proxy(
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methname, globals_, locals_)
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else:
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attr_names.add(methname)
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@classmethod
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def _create_method_proxy(cls, name, globals_, locals_):
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fn = getattr(cls, name)
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spec = inspect.getargspec(fn)
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if spec[0] and spec[0][0] == 'self':
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spec[0].pop(0)
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args = inspect.formatargspec(*spec)
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num_defaults = 0
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if spec[3]:
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num_defaults += len(spec[3])
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name_args = spec[0]
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if num_defaults:
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defaulted_vals = name_args[0 - num_defaults:]
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else:
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defaulted_vals = ()
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apply_kw = inspect.formatargspec(
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name_args, spec[1], spec[2],
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defaulted_vals,
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formatvalue=lambda x: '=' + x)
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def _name_error(name):
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raise NameError(
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"Can't invoke function '%s', as the proxy object has "
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"not yet been "
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"established for the Alembic '%s' class. "
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"Try placing this code inside a callable." % (
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name, cls.__name__
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))
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globals_['_name_error'] = _name_error
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translations = getattr(fn, "_legacy_translations", [])
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if translations:
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outer_args = inner_args = "*args, **kw"
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translate_str = "args, kw = _translate(%r, %r, %r, args, kw)" % (
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fn.__name__,
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tuple(spec),
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translations
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)
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def translate(fn_name, spec, translations, args, kw):
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return_kw = {}
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return_args = []
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for oldname, newname in translations:
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if oldname in kw:
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warnings.warn(
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"Argument %r is now named %r "
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"for method %s()." % (
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oldname, newname, fn_name
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))
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return_kw[newname] = kw.pop(oldname)
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return_kw.update(kw)
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args = list(args)
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if spec[3]:
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pos_only = spec[0][:-len(spec[3])]
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else:
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pos_only = spec[0]
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for arg in pos_only:
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if arg not in return_kw:
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try:
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return_args.append(args.pop(0))
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except IndexError:
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raise TypeError(
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"missing required positional argument: %s"
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% arg)
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return_args.extend(args)
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return return_args, return_kw
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globals_['_translate'] = translate
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else:
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outer_args = args[1:-1]
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inner_args = apply_kw[1:-1]
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translate_str = ""
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func_text = textwrap.dedent("""\
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def %(name)s(%(args)s):
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%(doc)r
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%(translate)s
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try:
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p = _proxy
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except NameError:
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_name_error('%(name)s')
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return _proxy.%(name)s(%(apply_kw)s)
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e
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""" % {
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'name': name,
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'translate': translate_str,
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'args': outer_args,
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'apply_kw': inner_args,
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'doc': fn.__doc__,
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})
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lcl = {}
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exec_(func_text, globals_, lcl)
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return lcl[name]
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def _with_legacy_names(translations):
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def decorate(fn):
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fn._legacy_translations = translations
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return fn
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return decorate
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def asbool(value):
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return value is not None and \
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value.lower() == 'true'
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def rev_id():
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return uuid.uuid4().hex[-12:]
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def to_list(x, default=None):
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if x is None:
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return default
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elif isinstance(x, string_types):
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return [x]
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elif isinstance(x, collections.Iterable):
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return list(x)
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else:
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return [x]
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def to_tuple(x, default=None):
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if x is None:
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return default
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elif isinstance(x, string_types):
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return (x, )
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elif isinstance(x, collections.Iterable):
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return tuple(x)
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else:
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return (x, )
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def unique_list(seq, hashfunc=None):
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seen = set()
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seen_add = seen.add
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if not hashfunc:
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return [x for x in seq
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if x not in seen
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and not seen_add(x)]
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else:
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return [x for x in seq
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if hashfunc(x) not in seen
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and not seen_add(hashfunc(x))]
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def dedupe_tuple(tup):
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return tuple(unique_list(tup))
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class memoized_property(object):
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"""A read-only @property that is only evaluated once."""
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def __init__(self, fget, doc=None):
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self.fget = fget
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self.__doc__ = doc or fget.__doc__
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self.__name__ = fget.__name__
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def __get__(self, obj, cls):
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if obj is None:
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return self
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obj.__dict__[self.__name__] = result = self.fget(obj)
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return result
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class immutabledict(dict):
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def _immutable(self, *arg, **kw):
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raise TypeError("%s object is immutable" % self.__class__.__name__)
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__delitem__ = __setitem__ = __setattr__ = \
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clear = pop = popitem = setdefault = \
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update = _immutable
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def __new__(cls, *args):
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new = dict.__new__(cls)
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dict.__init__(new, *args)
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return new
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def __init__(self, *args):
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pass
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def __reduce__(self):
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return immutabledict, (dict(self), )
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def union(self, d):
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if not self:
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return immutabledict(d)
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else:
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d2 = immutabledict(self)
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dict.update(d2, d)
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return d2
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def __repr__(self):
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return "immutabledict(%s)" % dict.__repr__(self)
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class Dispatcher(object):
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def __init__(self, uselist=False):
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self._registry = {}
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self.uselist = uselist
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def dispatch_for(self, target, qualifier='default'):
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def decorate(fn):
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if self.uselist:
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self._registry.setdefault((target, qualifier), []).append(fn)
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else:
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assert (target, qualifier) not in self._registry
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self._registry[(target, qualifier)] = fn
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return fn
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return decorate
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def dispatch(self, obj, qualifier='default'):
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if isinstance(obj, string_types):
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targets = [obj]
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elif isinstance(obj, type):
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targets = obj.__mro__
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else:
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targets = type(obj).__mro__
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for spcls in targets:
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if qualifier != 'default' and (spcls, qualifier) in self._registry:
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return self._fn_or_list(
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self._registry[(spcls, qualifier)])
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elif (spcls, 'default') in self._registry:
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return self._fn_or_list(
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self._registry[(spcls, 'default')])
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else:
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raise ValueError("no dispatch function for object: %s" % obj)
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def _fn_or_list(self, fn_or_list):
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if self.uselist:
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def go(*arg, **kw):
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for fn in fn_or_list:
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fn(*arg, **kw)
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return go
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else:
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return fn_or_list
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def branch(self):
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"""Return a copy of this dispatcher that is independently
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writable."""
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d = Dispatcher()
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if self.uselist:
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d._registry.update(
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(k, [fn for fn in self._registry[k]])
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for k in self._registry
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)
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else:
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d._registry.update(self._registry)
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return d
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