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# Copyright: 2005 Gentoo Foundation
# Author(s): Brian Harring (ferringb@gentoo.org)
# License: GPL2
# $Id$
import UserDict
import warnings
import weakref
class ProtectedDict(UserDict.DictMixin):
"""
given an initial dict, this wraps that dict storing changes in a secondary dict, protecting
the underlying dict from changes
"""
__slots__=("orig","new","blacklist")
def __init__(self, orig):
self.orig = orig
self.new = {}
self.blacklist = {}
def __setitem__(self, key, val):
self.new[key] = val
if key in self.blacklist:
del self.blacklist[key]
def __getitem__(self, key):
if key in self.new:
return self.new[key]
if key in self.blacklist:
raise KeyError(key)
return self.orig[key]
def __delitem__(self, key):
if key in self.new:
del self.new[key]
elif key in self.orig:
if key not in self.blacklist:
self.blacklist[key] = True
return
raise KeyError(key)
def __iter__(self):
for k in self.new.iterkeys():
yield k
for k in self.orig.iterkeys():
if k not in self.blacklist and k not in self.new:
yield k
def keys(self):
return list(self.__iter__())
def __contains__(self, key):
return key in self.new or (key not in self.blacklist and key in self.orig)
def has_key(self, key):
warnings.warn("portage.cache.mapping.ProtectedDict.has_key() is"
" deprecated, use the in operator instead",
DeprecationWarning)
return key in self
class LazyLoad(UserDict.DictMixin):
"""
Lazy loading of values for a dict
"""
__slots__=("pull", "d")
def __init__(self, pull_items_func, initial_items=[]):
self.d = {}
for k, v in initial_items:
self.d[k] = v
self.pull = pull_items_func
def __getitem__(self, key):
if key in self.d:
return self.d[key]
elif self.pull != None:
self.d.update(self.pull())
self.pull = None
return self.d[key]
def __iter__(self):
return iter(self.keys())
def keys(self):
if self.pull != None:
self.d.update(self.pull())
self.pull = None
return self.d.keys()
def has_key(self, key):
warnings.warn("portage.cache.mappings.LazyLoad.has_key() is "
"deprecated, use the in operator instead",
DeprecationWarning)
return key in self
def __contains__(self, key):
if key in self.d:
return True
elif self.pull != None:
self.d.update(self.pull())
self.pull = None
return key in self.d
_slot_dict_classes = weakref.WeakValueDictionary()
def slot_dict_class(keys, prefix="_val_"):
"""
Generates mapping classes that behave similar to a dict but store values
as object attributes that are allocated via __slots__. Instances of these
objects have a smaller memory footprint than a normal dict object.
@param keys: Fixed set of allowed keys
@type keys: Iterable
@param prefix: a prefix to use when mapping
attribute names from keys
@type prefix: String
@rtype: SlotDict
@returns: A class that constructs SlotDict instances
having the specified keys.
"""
if isinstance(keys, frozenset):
keys_set = keys
else:
keys_set = frozenset(keys)
v = _slot_dict_classes.get((keys_set, prefix))
if v is None:
class SlotDict(object):
allowed_keys = keys_set
_prefix = prefix
__slots__ = ("__weakref__",) + \
tuple(prefix + k for k in allowed_keys)
def __init__(self, *args, **kwargs):
if len(args) > 1:
raise TypeError(
"expected at most 1 positional argument, got " + \
repr(1 + len(args)))
if args:
self.update(args[0])
if kwargs:
self.update(kwargs)
def __iter__(self):
for k, v in self.iteritems():
yield k
def __len__(self):
l = 0
for i in self.iteritems():
l += 1
return l
def keys(self):
return list(self)
def iteritems(self):
for k in self.allowed_keys:
try:
yield (k, getattr(self, self._prefix + k))
except AttributeError:
pass
def items(self):
return list(self.iteritems())
def itervalues(self):
for k, v in self.iteritems():
yield v
def values(self):
return list(self.itervalues())
def __delitem__(self, k):
try:
delattr(self, self._prefix + k)
except AttributeError:
raise KeyError(k)
def __setitem__(self, k, v):
setattr(self, self._prefix + k, v)
def setdefault(self, key, default=None):
try:
return self[key]
except KeyError:
self[key] = default
return default
def update(self, d):
i = getattr(d, "iteritems", None)
if i is None:
i = d
else:
i = i()
for k, v in i:
self[k] = v
def __getitem__(self, k):
try:
return getattr(self, self._prefix + k)
except AttributeError:
raise KeyError(k)
def get(self, key, default=None):
try:
return self[key]
except KeyError:
return default
def __contains__(self, k):
return hasattr(self, self._prefix + k)
def has_key(self, k):
return k in self
def pop(self, key, *args):
if len(args) > 1:
raise TypeError(
"pop expected at most 2 arguments, got " + \
repr(1 + len(args)))
try:
value = self[key]
except KeyError:
if args:
return args[0]
raise
del self[key]
return value
def popitem(self):
try:
k, v = self.iteritems().next()
except StopIteration:
raise KeyError('container is empty')
del self[k]
return (k, v)
def copy(self):
c = self.__class__()
c.update(self)
return c
def clear(self):
for k in self.allowed_keys:
try:
delattr(self, self._prefix + k)
except AttributeError:
pass
v = SlotDict
_slot_dict_classes[v.allowed_keys] = v
return v
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