137 lines
5 KiB
Python
137 lines
5 KiB
Python
# -*- coding=UTF-8; tab-width: 4 -*-
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# Heavily modified version of the code featured at the given link
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## {{{ http://code.activestate.com/recipes/473786/ (r1)
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class AttrDict(dict):
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"""A dictionary with attribute-style access. It maps attribute access to
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the real dictionary.
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Note that accesses to preexisting (e.g. class inherited) or reserved
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attributes are handled as they would be normally, and will not be
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overwritten.
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Overload _is_reserved if you want to change this."""
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def __init__(self, init={}):
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super(AttrDict, self).__init__(init)
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def __getstate__(self):
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return list(self.__dict__.items())
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def __setstate__(self, items):
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for key, val in items: self.__dict__[key] = val
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def __repr__(self):
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return "{0}({1})".format(
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type(self).__name__,
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super(AttrDict, self).__repr__()
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)
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def __setitem__(self, name, value):
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return super(AttrDict, self).__setitem__(name, value)
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def __getitem__(self, name):
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return super(AttrDict, self).__getitem__(name)
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def __delitem__(self, name):
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return super(AttrDict, self).__delitem__(name)
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def __getattr__(self, name):
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# NOTE: __getattr__ is called if the code has already failed to access
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# an attribute on this object. The rest of this code reflects this.
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# We could override __getattribute__ to bypass this, but that's not
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# worthwhile.
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# We don't do any special handling for reserved names.
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if self._is_reserved(name):
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# Fall back to normal handling, by force.
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return object.__getattribute__(self, name)
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try:
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# Try to __getitem__.
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result = self[name]
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except (KeyError, AttributeError):
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# Raising KeyError here will confuse __deepcopy__, so don't do
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# that.
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# Throw a custom error.
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raise AttributeError("No key/attr {0!r}".format(name))
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return result
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def __setattr__(self, name, value):
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# Set to the attribute first if it's defined.
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# (NOTE: This isn't subject to the same checking as __getattr__.)
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# Using dir() also checks non-instance definitions, so things defined
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# on a class can be easily set on an instance this way.
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# Detect special/reserved names.
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if name in dir(self) or self._is_reserved(name):
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# Set it if it's 'special' because we aren't supposed to touch any
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# of that - too many potential implementation issues.
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#
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# Apparently we're also not supposed to set our own dict directly
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# in this particular function?...
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return object.__setattr__(self, name, value)
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else:
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return super(AttrDict, self).__setitem__(name, value)
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def __delattr__(self, name):
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# We very *specifically* use self.__dict__ here, because we couldn't
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# possibly delete a value that doesn't yet *exist* in our instance's
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# namespace yet!
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# This shouldn't be a problem, since this type should never have
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# __slots__.
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if name in self.__dict__:
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# See __setattr__.
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return object.__delattr__(self, name)
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else:
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try: del self[name]
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except KeyError as err:
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raise AttributeError(str(err))
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@staticmethod
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def _is_reserved(name):
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"""Check if an attribute name is reserved for system use."""
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# A very simple method.
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result = name[:2] == name[-2:] == '__'
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return result
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def copy(self): return type(self)(self)
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__copy__ = copy
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## end of http://code.activestate.com/recipes/473786/ }}}
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class DefAttrDict(AttrDict):
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default_factory = None
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def __init__(self, default_factory=None, *args, **kwargs):
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self.default_factory = default_factory
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super(DefAttrDict, self).__init__(*args, **kwargs)
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def __repr__(self):
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return "{0}({1!r}, {2})".format(
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type(self).__name__,
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self.default_factory,
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# We skip normal processing here, since AttrDict provides basic
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# repr for classes in general, which we don't want.
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dict.__repr__(self)
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)
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def __getitem__(self, name):
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try:
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result = super(DefAttrDict, self).__getitem__(name)
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except KeyError:
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result = None
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if self.default_factory is not None:
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result = self.default_factory()
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self[name] = result
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return result
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def __getattr__(self, name):
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try:
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result = super(DefAttrDict, self).__getattr__(name)
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except AttributeError:
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# Detect special/reserved names.
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if self._is_reserved(name):
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# We shouldn't automatically fill these in.
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# Pass this along.
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raise
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return result
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def copy(self): return type(self)(self.default_factory, self)
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__copy__ = copy
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# vim: set autoindent ts=4 sts=4 sw=4 textwidth=79 expandtab:
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