def addLazySingleton(self, item_key, value_callable, *pargs, **kwargs): """This is like addLazyItem except value_callable will only be called a maximum of 1 time and the result will be cached for future requests.""" self.lazy_items[item_key] = \ self._LazyItem(value_callable, pargs, kwargs, True) # make it show up in self.keys(), etc... UserDict.__setitem__(self, item_key, None)
def addLazySingleton(self, item_key, value_callable, *pargs, **kwargs): """This is like addLazyItem except value_callable will only be called a maximum of 1 time and the result will be cached for future requests.""" self.lazy_items[item_key] = \ self._LazyItem(value_callable, pargs, kwargs, True) # make it show up in self.keys(), etc... UserDict.__setitem__(self, item_key, None)
def addLazyItem(self, item_key, value_callable, *pargs, **kwargs): """Add a lazy item for the given key. When the item is requested, value_callable will be called with *pargs and **kwargs arguments.""" self.lazy_items[item_key] = \ self._LazyItem(value_callable, pargs, kwargs, False) # make it show up in self.keys(), etc... UserDict.__setitem__(self, item_key, None)
def addLazyItem(self, item_key, value_callable, *pargs, **kwargs): """Add a lazy item for the given key. When the item is requested, value_callable will be called with *pargs and **kwargs arguments.""" self.lazy_items[item_key] = \ self._LazyItem(value_callable, pargs, kwargs, False) # make it show up in self.keys(), etc... UserDict.__setitem__(self, item_key, None)
def __deepcopy__(self, memo=None):
"""
This forces evaluation of each contained lazy item, and deepcopy of
the result. A TypeError is raised if any contained lazy item is not
a singleton, since it is not necessarily possible for the behavior
of this type of item to be safely preserved.
"""
if memo is None:
memo = {}
result = self.__class__()
memo[id(self)] = result
for k in self:
k_copy = deepcopy(k, memo)
lazy_item = self.lazy_items.get(k)
if lazy_item is not None:
if not lazy_item.singleton:
raise TypeError(_unicode_decode("LazyItemsDict " + \
"deepcopy is unsafe with lazy items that are " + \
"not singletons: key=%s value=%s") % (k, lazy_item,))
UserDict.__setitem__(result, k_copy, deepcopy(self[k], memo))
return result
def update(self, *args, **kwargs): if len(args) > 1: raise TypeError( "expected at most 1 positional argument, got " + \ repr(len(args))) if args: map_obj = args[0] else: map_obj = None if map_obj is None: pass elif isinstance(map_obj, LazyItemsDict): for k in map_obj: if k in map_obj.lazy_items: UserDict.__setitem__(self, k, None) else: UserDict.__setitem__(self, k, map_obj[k]) self.lazy_items.update(map_obj.lazy_items) else: UserDict.update(self, map_obj) if kwargs: UserDict.update(self, kwargs)
def update(self, *args, **kwargs): if len(args) > 1: raise TypeError( "expected at most 1 positional argument, got " + \ repr(len(args))) if args: map_obj = args[0] else: map_obj = None if map_obj is None: pass elif isinstance(map_obj, LazyItemsDict): for k in map_obj: if k in map_obj.lazy_items: UserDict.__setitem__(self, k, None) else: UserDict.__setitem__(self, k, map_obj[k]) self.lazy_items.update(map_obj.lazy_items) else: UserDict.update(self, map_obj) if kwargs: UserDict.update(self, kwargs)
def __deepcopy__(self, memo=None):
"""
WARNING: If any of the lazy items contains a bound method then it's
typical for deepcopy() to raise an exception like this:
File "/usr/lib/python2.5/copy.py", line 189, in deepcopy
y = _reconstruct(x, rv, 1, memo)
File "/usr/lib/python2.5/copy.py", line 322, in _reconstruct
y = callable(*args)
File "/usr/lib/python2.5/copy_reg.py", line 92, in __newobj__
return cls.__new__(cls, *args)
TypeError: instancemethod expected at least 2 arguments, got 0
If deepcopy() needs to work, this problem can be avoided by
implementing lazy items with normal (non-bound) functions.
If deepcopy() raises a TypeError for a lazy item that has been added
via a call to addLazySingleton(), the singleton will be automatically
evaluated and deepcopy() will instead be called on the result.
"""
if memo is None:
memo = {}
result = self.__class__()
memo[id(self)] = result
for k in self:
k_copy = deepcopy(k, memo)
if k in self.lazy_items:
lazy_item = self.lazy_items[k]
try:
result.lazy_items[k_copy] = deepcopy(lazy_item, memo)
except TypeError:
if not lazy_item.singleton:
raise
UserDict.__setitem__(result,
k_copy, deepcopy(self[k], memo))
else:
UserDict.__setitem__(result, k_copy, None)
else:
UserDict.__setitem__(result, k_copy, deepcopy(self[k], memo))
return result
def __deepcopy__(self, memo=None):
"""
WARNING: If any of the lazy items contains a bound method then it's
typical for deepcopy() to raise an exception like this:
File "/usr/lib/python2.5/copy.py", line 189, in deepcopy
y = _reconstruct(x, rv, 1, memo)
File "/usr/lib/python2.5/copy.py", line 322, in _reconstruct
y = callable(*args)
File "/usr/lib/python2.5/copy_reg.py", line 92, in __newobj__
return cls.__new__(cls, *args)
TypeError: instancemethod expected at least 2 arguments, got 0
If deepcopy() needs to work, this problem can be avoided by
implementing lazy items with normal (non-bound) functions.
If deepcopy() raises a TypeError for a lazy item that has been added
via a call to addLazySingleton(), the singleton will be automatically
evaluated and deepcopy() will instead be called on the result.
"""
if memo is None:
memo = {}
result = self.__class__()
memo[id(self)] = result
for k in self:
k_copy = deepcopy(k, memo)
if k in self.lazy_items:
lazy_item = self.lazy_items[k]
try:
result.lazy_items[k_copy] = deepcopy(lazy_item, memo)
except TypeError:
if not lazy_item.singleton:
raise
UserDict.__setitem__(result,
k_copy, deepcopy(self[k], memo))
else:
UserDict.__setitem__(result, k_copy, None)
else:
UserDict.__setitem__(result, k_copy, deepcopy(self[k], memo))
return result
def __setitem__(self, item_key, value): if item_key in self.lazy_items: del self.lazy_items[item_key] UserDict.__setitem__(self, item_key, value)
def __setitem__(self, item_key, value): if item_key in self.lazy_items: del self.lazy_items[item_key] UserDict.__setitem__(self, item_key, value)
