mirror of
https://github.com/janeczku/calibre-web
synced 2024-11-05 17:46:22 +00:00
164 lines
4.4 KiB
Python
164 lines
4.4 KiB
Python
from weakref import ref
|
|
|
|
from blinker._saferef import BoundMethodWeakref
|
|
|
|
|
|
try:
|
|
callable
|
|
except NameError:
|
|
def callable(object):
|
|
return hasattr(object, '__call__')
|
|
|
|
|
|
try:
|
|
from collections import defaultdict
|
|
except:
|
|
class defaultdict(dict):
|
|
|
|
def __init__(self, default_factory=None, *a, **kw):
|
|
if (default_factory is not None and
|
|
not hasattr(default_factory, '__call__')):
|
|
raise TypeError('first argument must be callable')
|
|
dict.__init__(self, *a, **kw)
|
|
self.default_factory = default_factory
|
|
|
|
def __getitem__(self, key):
|
|
try:
|
|
return dict.__getitem__(self, key)
|
|
except KeyError:
|
|
return self.__missing__(key)
|
|
|
|
def __missing__(self, key):
|
|
if self.default_factory is None:
|
|
raise KeyError(key)
|
|
self[key] = value = self.default_factory()
|
|
return value
|
|
|
|
def __reduce__(self):
|
|
if self.default_factory is None:
|
|
args = tuple()
|
|
else:
|
|
args = self.default_factory,
|
|
return type(self), args, None, None, self.items()
|
|
|
|
def copy(self):
|
|
return self.__copy__()
|
|
|
|
def __copy__(self):
|
|
return type(self)(self.default_factory, self)
|
|
|
|
def __deepcopy__(self, memo):
|
|
import copy
|
|
return type(self)(self.default_factory,
|
|
copy.deepcopy(self.items()))
|
|
|
|
def __repr__(self):
|
|
return 'defaultdict(%s, %s)' % (self.default_factory,
|
|
dict.__repr__(self))
|
|
|
|
|
|
try:
|
|
from contextlib import contextmanager
|
|
except ImportError:
|
|
def contextmanager(fn):
|
|
def oops(*args, **kw):
|
|
raise RuntimeError("Python 2.5 or above is required to use "
|
|
"context managers.")
|
|
oops.__name__ = fn.__name__
|
|
return oops
|
|
|
|
class _symbol(object):
|
|
|
|
def __init__(self, name):
|
|
"""Construct a new named symbol."""
|
|
self.__name__ = self.name = name
|
|
|
|
def __reduce__(self):
|
|
return symbol, (self.name,)
|
|
|
|
def __repr__(self):
|
|
return self.name
|
|
_symbol.__name__ = 'symbol'
|
|
|
|
|
|
class symbol(object):
|
|
"""A constant symbol.
|
|
|
|
>>> symbol('foo') is symbol('foo')
|
|
True
|
|
>>> symbol('foo')
|
|
foo
|
|
|
|
A slight refinement of the MAGICCOOKIE=object() pattern. The primary
|
|
advantage of symbol() is its repr(). They are also singletons.
|
|
|
|
Repeated calls of symbol('name') will all return the same instance.
|
|
|
|
"""
|
|
symbols = {}
|
|
|
|
def __new__(cls, name):
|
|
try:
|
|
return cls.symbols[name]
|
|
except KeyError:
|
|
return cls.symbols.setdefault(name, _symbol(name))
|
|
|
|
|
|
try:
|
|
text = (str, unicode)
|
|
except NameError:
|
|
text = str
|
|
|
|
|
|
def hashable_identity(obj):
|
|
if hasattr(obj, '__func__'):
|
|
return (id(obj.__func__), id(obj.__self__))
|
|
elif hasattr(obj, 'im_func'):
|
|
return (id(obj.im_func), id(obj.im_self))
|
|
elif isinstance(obj, text):
|
|
return obj
|
|
else:
|
|
return id(obj)
|
|
|
|
|
|
WeakTypes = (ref, BoundMethodWeakref)
|
|
|
|
|
|
class annotatable_weakref(ref):
|
|
"""A weakref.ref that supports custom instance attributes."""
|
|
|
|
|
|
def reference(object, callback=None, **annotations):
|
|
"""Return an annotated weak ref."""
|
|
if callable(object):
|
|
weak = callable_reference(object, callback)
|
|
else:
|
|
weak = annotatable_weakref(object, callback)
|
|
for key, value in annotations.items():
|
|
setattr(weak, key, value)
|
|
return weak
|
|
|
|
|
|
def callable_reference(object, callback=None):
|
|
"""Return an annotated weak ref, supporting bound instance methods."""
|
|
if hasattr(object, 'im_self') and object.im_self is not None:
|
|
return BoundMethodWeakref(target=object, on_delete=callback)
|
|
elif hasattr(object, '__self__') and object.__self__ is not None:
|
|
return BoundMethodWeakref(target=object, on_delete=callback)
|
|
return annotatable_weakref(object, callback)
|
|
|
|
|
|
class lazy_property(object):
|
|
"""A @property that is only evaluated once."""
|
|
|
|
def __init__(self, deferred):
|
|
self._deferred = deferred
|
|
self.__doc__ = deferred.__doc__
|
|
|
|
def __get__(self, obj, cls):
|
|
if obj is None:
|
|
return self
|
|
value = self._deferred(obj)
|
|
setattr(obj, self._deferred.__name__, value)
|
|
return value
|