# Coverage for pygeodesy/props.py : 97%

## 92 statements 89 run 3 missing 11 excluded

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 | # -*- coding: utf-8 -*- u'''Im-/mutable, caching or memoizing properties and decorators. ''' from pygeodesy.errors import _AssertionError, _AttributeError from pygeodesy.interns import NN, _DOT_, _EQUALSPACED_, \ _immutable_, _invalid_, _N_A_, \ _SPACE_, _UNDER_ from pygeodesy.lazily import _ALL_LAZY, _FOR_DOCS __all__ = _ALL_LAZY.props __version__ = '21.01.26' def _hasProperty(inst, name, *Classes): '''(INTERNAL) Check whether C{inst} has a C{P/property/_RO} by this C{name}. ''' ps = Classes if Classes else _PropertyBase for c in inst.__class__.__mro__[:-1]: p = c.__dict__.get(name, None) if isinstance(p, ps) and p.name == name: return True return False def _update_all(inst, *attrs): '''(INTERNAL) Zap all I{cached} L{property_RO}s, L{Property_RO}s and the named C{attrs} from an instance' C{__dict__}. @return: The number of updates (C{int}), if any. ''' d = inst.__dict__ u = len(d) for c in inst.__class__.__mro__[:-1]: for n, p in c.__dict__.items(): if isinstance(p, _PropertyBase) and p.name == n: p._update(inst, c) for a in attrs: if hasattr(inst, a): d.pop(a, None) else: # PYCHOK no cover from pygeodesy.named import classname n = classname(inst, prefixed=True) a = _DOT_(n, _SPACE_(a, _invalid_)) raise _AssertionError(a, txt=repr(inst)) return u - len(d) class _PropertyBase(property): '''(INTERNAL) Base class for C{P/property/_RO}. ''' def __init__(self, method, fget, fset): if not callable(method): self.getter(method) # PYCHOK no cover self.method = method self.name = method.__name__ if _FOR_DOCS and method.__doc__: self.__doc__ = method.__doc__ # PYCHOK no cover property.__init__(self, fget, fset, self._fdel, method.__doc__ or _N_A_) def _fdel(self, inst): # deleter self._update(inst, None) # PYCHOK no cover def _fget(self, inst): try: # to get the value cached in instance' __dict__ return inst.__dict__[self.name] except KeyError: # cache the value in the instance' __dict__ inst.__dict__[self.name] = val = self.method(inst) return val def _fset_error(self, inst, val): '''Throws an C{AttributeError}, always. ''' from pygeodesy.named import classname n = _DOT_(classname(inst), self.name) self._immutable_error(_EQUALSPACED_(n, repr(val))) def _immutable_error(self, name): from pygeodesy.named import classname e = _SPACE_(_immutable_, classname(self)) raise _AttributeError(e, txt=name) def _invalid_error(self, name): from pygeodesy.named import classname e = _SPACE_(_invalid_, classname(self)) raise _AttributeError(e, txt=name) def _update(self, inst, *unused): '''(INTERNAL) Zap the I{cached} C{inst.__dict__[name]} item. ''' inst.__dict__.pop(self.name, None) def deleter(self, fdel): '''Throws an C{AttributeError}, always. ''' n = _DOT_(self.name, self.deleter.__name__) self._invalid_error(_SPACE_(n, fdel.__name__)) def getter(self, fget): '''Throws an C{AttributeError}, always. ''' n = _DOT_(self.name, self.getter.__name__) self._invalid_error(_SPACE_(n, fget.__name__)) def setter(self, fset): '''Throws an C{AttributeError}, always. ''' n = _DOT_(self.name, self.setter.__name__) self._immutable_error(_SPACE_(n, fset.__name__)) class Property_RO(_PropertyBase): # No __doc__ on purpose def __init__(self, method): # PYCHOK expected '''New I{immutable}, I{caching}, I{memoizing} C{property} I{Factory} to be used as C{decorator}. @arg method: The callable being decorated as this C{property}'s C{getter}, to be invoked only once. @note: Like standard Python C{property} without a C{setter}, but with a more descriptive error message when set. @see: Python 3's U{functools.cached_property<https://docs.Python.org/3/ library/functools.html#functools.cached_property>} and U{-.cache <https://Docs.Python.org/3/library/functools.html#functools.cache>} to I{cache} or I{memoize} the property value. @see: Luciano Ramalho, "Fluent Python", page 636, O'Reilly, 2016, "Coding a Property Factory", especially Example 19-24 and U{class Property<https://docs.Python.org/3/howto/descriptor.html>}. ''' _PropertyBase.__init__(self, method, self._fget, self._fset_error) def __get__(self, inst, *unused): # PYCHOK 2 vs 3 args if inst is None: return self try: # to get the cached value immediately return inst.__dict__[self.name] except (AttributeError, KeyError): return self._fget(inst) class Property(Property_RO): # No __doc__ on purpose __init__ = Property_RO.__init__ '''New I{mutable}, I{caching}, I{memoizing} C{property} I{Factory} to be used as C{decorator}. @see: L{Property_RO} for more details. @note: Unless and until the C{setter} is defined, this L{Property} behaves like an I{immutable}, I{caching}, I{memoizing} L{Property_RO}. ''' def setter(self, method): '''Make this C{Property} I{mutable}. @arg method: The callable being decorated as this C{Property}'s C{setter}. @note: Setting a new property value always clears the previously I{cached} or I{memoized} value I{after} invoking the B{C{method}}. ''' if not callable(method): _PropertyBase.setter(self, method) # PYCHOK no cover def _fset(inst, val): method(inst, val) self._update(inst) # un-cache this item # class Property <https://docs.Python.org/3/howto/descriptor.html> _PropertyBase.__init__(self, self.method, self._fget, _fset) return self class property_RO(_PropertyBase): # No __doc__ on purpose def __init__(self, method): # PYCHOK expected '''New I{immutable}, standard C{property} to be used as C{decorator}. @arg method: The callable being decorated as C{property}'s C{getter}. @note: Like standard Python C{property} without a setter, but with a more descriptive error message when set. @see: L{Property_RO}. ''' _PropertyBase.__init__(self, method, method, self._fset_error) def _update(self, inst, clas=None): # PYCHOK signature '''(INTERNAL) Zap the I{cached} C{inst.__dict__[_name]} item. ''' c = clas or inst.__class__ if c: _n = NN(_UNDER_, self.name) if c.__dict__.get(_n, False) is None: # in (None, ()): inst.__dict__.pop(_n, None) def property_doc_(doc): '''Decorator for a standard C{property} with basic documentation. @arg doc: The property documentation (C{str}). @example: >>> @property_doc_("documentation text.") >>> def name(self): >>> ... >>> >>> @name.setter >>> def name(self, value): >>> ... ''' # See Luciano Ramalho, "Fluent Python", page 212ff, O'Reilly, 2016, # "Parameterized Decorators", especially Example 7-23. Also, see # <https://Python-3-Patterns-Idioms-Test.ReadTheDocs.io/en/latest/PythonDecorators.html> def _documented_property(method): '''(INTERNAL) Return the documented C{property}. ''' t = 'get and set' if doc.startswith(_SPACE_) else NN return property(method, None, None, NN('Property to ', t, doc)) return _documented_property # **) MIT License # # Copyright (C) 2016-2021 -- mrJean1 at Gmail -- All Rights Reserved. # # Permission is hereby granted, free of charge, to any person obtaining a # copy of this software and associated documentation files (the "Software"), # to deal in the Software without restriction, including without limitation # the rights to use, copy, modify, merge, publish, distribute, sublicense, # and/or sell copies of the Software, and to permit persons to whom the # Software is furnished to do so, subject to the following conditions: # # The above copyright notice and this permission notice shall be included # in all copies or substantial portions of the Software. # # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS # OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL # THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR # OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, # ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR # OTHER DEALINGS IN THE SOFTWARE.