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# -*- coding: utf-8 -*- 

 

u'''Mutable, immutable and caching/memoizing properties and 

deprecation decorators. 

 

To enable C{DeprecationWarning}s from C{PyGeodesy}, set env var 

C{PYGEODESY_WARNINGS} to a non-empty string I{AND} run C{python} 

with command line option C{-X dev} or with one of the C{-W} 

choices, see function L{DeprecationWarnings} below. 

''' 

 

from pygeodesy.basics import isclass 

from pygeodesy.errors import _AssertionError, _AttributeError, \ 

_xkwds, _xkwds_get 

from pygeodesy.interns import MISSING, NN, _an_, _COMMASPACE_, \ 

_DEPRECATED_, _DNL_, _DOT_, _EQUALSPACED_, \ 

_immutable_, _invalid_, _N_A_, _not_, \ 

_SPACE_, _UNDER_ 

# from pygeodesy.named import callname # from _MODS, avoid circular 

from pygeodesy.lazily import _ALL_LAZY, _ALL_MODS as _MODS, _getenv, \ 

_FOR_DOCS, _PYTHON_X_DEV, _sys 

# from pygeodesy.streprs import Fmt # from _MODS 

 

from functools import wraps as _wraps 

 

__all__ = _ALL_LAZY.props 

__version__ = '22.09.16' 

 

_dont_use_ = _DEPRECATED_ + ", don't use." 

_has_been_ = 'has been' 

_not_an_inst_ = _not_(_an_, 'instance') 

_Warnings = 0 

_W_DEV = (bool(_sys.warnoptions) or _PYTHON_X_DEV) \ 

and _getenv('PYGEODESY_WARNINGS', NN) 

 

 

def _allPropertiesOf(Clas_or_inst, *Bases): 

'''(INTERNAL) Yield all C{R/property/_RO}s at C{Clas_or_inst} 

as specified in the C{Bases} arguments. 

''' 

if isclass(Clas_or_inst): 

S = Clas_or_inst, # just this Clas 

else: # class and super-classes of inst 

try: 

S = Clas_or_inst.__class__.__mro__[:-1] # not object 

except AttributeError: 

raise 

S = () # not an inst 

B = Bases or _PropertyBase 

for C in S: 

for n, p in C.__dict__.items(): 

if isinstance(p, B) and p.name == n: 

yield p 

 

 

def _allPropertiesOf_n(n, Clas_or_inst, *Bases): 

'''(INTERNAL) Assert the number of C{R/property/_RO}s at C{Clas_or_inst}. 

''' 

t = tuple(p.name for p in _allPropertiesOf(Clas_or_inst, *Bases)) 

if len(t) != n: 

raise _AssertionError(_COMMASPACE_.join(t), Clas_or_inst, 

txt=_COMMASPACE_(len(t), _not_(n))) 

return t 

 

 

def _hasProperty(inst, name, *Classes): # in .named._NamedBase._update 

'''(INTERNAL) Check whether C{inst} has a C{P/property/_RO} by this C{name}. 

''' 

p = getattr(inst.__class__, name, None) # walks __class__.__mro__ 

return bool(p and isinstance(p, Classes or _PropertyBase) 

and p.name == name) 

 

 

def _update_all(inst, *attrs, **Base): 

'''(INTERNAL) Zap all I{cached} L{property_RO}s, L{Property}s, 

L{Property_RO}s and the named C{attrs} of an instance. 

 

@return: The number of updates (C{int}), if any. 

''' 

if isclass(inst): 

raise _AssertionError(inst, txt=_not_an_inst_) 

try: 

d = inst.__dict__ 

except AttributeError: 

return 0 

u = len(d) 

if u: 

B = _xkwds_get(Base, Base=_PropertyBase) 

for p in _allPropertiesOf(inst, B): 

p._update(inst) # d.pop(p.name, None) 

 

if attrs: 

_update_attrs(inst, *attrs) # remove attributes from inst.__dict__ 

u -= len(d) 

return u # updates 

 

 

# def _update_all_from(inst, other, **Base): 

# '''(INTERNAL) Update all I{cached} L{Property}s and 

# L{Property_RO}s of instance C{inst} from C{other}. 

# 

# @return: The number of updates (C{int}), if any. 

# ''' 

# if isclass(inst): 

# raise _AssertionError(inst, txt=_not_an_inst_) 

# try: 

# d = inst.__dict__ 

# f = other.__dict__ 

# except AttributeError: 

# return 0 

# u = len(f) 

# if u: 

# u = len(d) 

# B = _xkwds_get(Base, Base=_PropertyBase) 

# for p in _allPropertiesOf(inst, B): 

# p._update_from(inst, other) 

# u -= len(d) 

# return u # updates 

 

 

def _update_attrs(inst, *attrs): 

'''(INTERNAL) Zap all named C{attrs} of an instance. 

 

@return: The number of updates (C{int}), if any. 

''' 

try: 

d = inst.__dict__ 

except AttributeError: 

return 0 

u = len(d) 

if u: 

_p = d.pop # zap attrs from inst.__dict__ 

for a in attrs: # PYCHOK no cover 

if _p(a, MISSING) is MISSING and not hasattr(inst, a): 

n = _MODS.named.classname(inst, prefixed=True) 

a = _DOT_(n, _SPACE_(a, _invalid_)) 

raise _AssertionError(a, txt=repr(inst)) 

u -= len(d) 

return u # updates 

 

 

class _PropertyBase(property): 

'''(INTERNAL) Base class for C{P/property/_RO}. 

''' 

def __init__(self, method, fget, fset, doc=NN): 

 

if not callable(method): 

self.getter(method) # PYCHOK no cover 

 

self.method = method 

self.name = method.__name__ 

d = doc or method.__doc__ 

if _FOR_DOCS and d: 

self.__doc__ = d # PYCHOK no cover 

 

property.__init__(self, fget, fset, self._fdel, d or _N_A_) 

 

def _fdel(self, inst): 

'''Zap the I{cached/memoized} C{property} value. 

''' 

self._update(inst, None) # PYCHOK no cover 

 

def _fget(self, inst): 

'''Get and I{cache/memoize} the C{property} value. 

''' 

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. 

''' 

n = _MODS.named.classname(inst) 

n = _DOT_(n, self.name) 

n = _EQUALSPACED_(n, repr(val)) 

raise self._Error(_immutable_, n, None) 

 

def _update(self, inst, *unused): 

'''(INTERNAL) Zap the I{cached/memoized} C{inst.__dict__[name]} item. 

''' 

inst.__dict__.pop(self.name, None) # name, NOT _name 

 

def _update_from(self, inst, other): 

'''(INTERNAL) Copy a I{cached/memoized} C{inst.__dict__[name]} item 

from C{other.__dict__[name]} if present, otherwise zap it. 

''' 

n = self.name # name, NOT _name 

v = other.__dict__.get(n, MISSING) 

if v is MISSING: 

inst.__dict__.pop(n, None) 

else: 

inst.__dict__[n] = v 

 

def deleter(self, fdel): 

'''Throws an C{AttributeError}, always. 

''' 

raise self._Error(_invalid_, self.deleter, fdel) 

 

def getter(self, fget): 

'''Throws an C{AttributeError}, always. 

''' 

raise self._Error(_invalid_, self.getter, fget) 

 

def setter(self, fset): 

'''Throws an C{AttributeError}, always. 

''' 

raise self._Error(_immutable_, self.setter, fset) 

 

def _Error(self, kind, nameter, farg): 

'''(INTERNAL) Return an C{AttributeError} instance. 

''' 

if farg: 

n = _DOT_(self.name, nameter.__name__) 

n = _SPACE_(n, farg.__name__) 

else: 

n = nameter 

e = _SPACE_(kind, _MODS.named.classname(self)) 

return _AttributeError(e, txt=n) 

 

 

class Property_RO(_PropertyBase): 

# No __doc__ on purpose 

def __init__(self, method, doc=NN): # 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. 

@kwarg doc: Optional property documentation (C{str}). 

 

@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>}. 

''' 

_fget = method if _FOR_DOCS else self._fget # XXX force method.__doc__ to epydoc 

_PropertyBase.__init__(self, method, _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 

 

if _FOR_DOCS: # XXX force method.__doc__ into epydoc 

_PropertyBase.__init__(self, self.method, self.method, method) 

else: 

 

def _fset(inst, val): 

'''Set and I{cache}, I{memoize} the C{property} value. 

''' 

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 

_uname = NN 

 

def __init__(self, method, doc=NN): # 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}. 

@kwarg doc: Optional property documentation (C{str}). 

 

@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, doc=doc) 

self._uname = NN(_UNDER_, self.name) # actual attr UNDER<name> 

 

def _update(self, inst, *Clas): # PYCHOK signature 

'''(INTERNAL) Zap the I{cached} C{B{inst}.__dict__[_name]} item. 

''' 

uname = self._uname 

if uname in inst.__dict__: 

if Clas: # overrides inst.__class__ 

d = Clas[0].__dict__.get(uname, MISSING) 

else: 

d = getattr(inst.__class__, uname, MISSING) 

# if d is MISSING: # XXX superfluous 

# for c in inst.__class__.__mro__[:-1]: 

# if uname in c.__dict__: 

# d = c.__dict__[uname] 

# break 

if d is None: # remove inst value 

inst.__dict__.pop(uname) 

 

 

class _NamedProperty(property): 

'''Class C{property} with retrievable name. 

''' 

@Property_RO 

def name(self): 

'''Get the name of this C{property} (C{str}). 

''' 

return self.fget.__name__ 

 

 

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 _NamedProperty(method, None, None, NN('Property to ', t, doc)) 

 

return _documented_property 

 

 

def _deprecated(call, kind, qual_d): 

'''(INTERNAL) Decorator for DEPRECATED functions, methods, etc. 

 

@see: Brett Slatkin, "Effective Python", page 105, 2nd ed, 

Addison-Wesley, 2019. 

''' 

doc = _docof(call) 

 

@_wraps(call) # PYCHOK self? 

def _deprecated_call(*args, **kwds): 

if qual_d: # function 

q = qual_d 

elif args: # method 

q = _qualified(args[0], call.__name__) 

else: # PYCHOK no cover 

q = call.__name__ 

_throwarning(kind, q, doc) 

return call(*args, **kwds) 

 

return _deprecated_call 

 

 

def deprecated_class(cls_or_class): 

'''Use inside __new__ or __init__ of a DEPRECATED class. 

 

@arg cls_or_class: The class (C{cls} or C{Class}). 

 

@note: NOT a decorator! 

''' 

if _W_DEV: 

q = _DOT_(cls_or_class.__module__, cls_or_class.__name__) 

_throwarning('class', q, cls_or_class.__doc__) 

 

 

def deprecated_function(call): 

'''Decorator for a DEPRECATED function. 

 

@arg call: The deprecated function (C{callable}). 

 

@return: The B{C{call}} DEPRECATED. 

''' 

return _deprecated(call, 'function', _DOT_( 

call.__module__, call.__name__)) if \ 

_W_DEV else call 

 

 

def deprecated_method(call): 

'''Decorator for a DEPRECATED method. 

 

@arg call: The deprecated method (C{callable}). 

 

@return: The B{C{call}} DEPRECATED. 

''' 

return _deprecated(call, 'method', NN) if _W_DEV else call 

 

 

def _deprecated_module(name): # PYCHOK no cover 

'''(INTERNAL) Callable within a DEPRECATED module. 

''' 

if _W_DEV: 

_throwarning('module', name, _dont_use_) 

 

 

if _W_DEV: 

class deprecated_property(_PropertyBase): 

'''Decorator for a DEPRECATED C{property} or C{Property}. 

''' 

def __init__(self, method): 

'''Decorator for a DEPRECATED C{property} or C{Property} getter. 

''' 

doc = _docof(method) 

 

def _fget(inst): # PYCHOK no cover 

'''Get the C{property} or C{Property} value. 

''' 

q = _qualified(inst, self.name) 

_throwarning(property.__name__, q, doc) 

return self.method(inst) # == method 

 

_PropertyBase.__init__(self, method, _fget, None, doc=doc) 

 

def setter(self, method): 

'''Decorator for a DEPRECATED C{property} or C{Property} setter. 

 

@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 

 

if _FOR_DOCS: # XXX force method.__doc__ into epydoc 

_PropertyBase.__init__(self, self.method, self.method, method) 

else: 

 

def _fset(inst, val): 

'''Set the C{property} or C{Property} value. 

''' 

q = _qualified(inst, self.name) 

_throwarning(property.__name__, q, _docof(method)) 

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 

 

else: # PYCHOK no cover 

class deprecated_property(property): # PYCHOK expected 

'''Decorator for a DEPRECATED C{property} or C{Property}. 

''' 

pass 

 

deprecated_Property = deprecated_property 

 

 

def deprecated_Property_RO(method): 

'''Decorator for a DEPRECATED L{Property_RO}. 

 

@arg method: The C{Property_RO.fget} method (C{callable}). 

 

@return: The B{C{method}} DEPRECATED. 

''' 

return _deprecated_RO(method, Property_RO) 

 

 

def deprecated_property_RO(method): 

'''Decorator for a DEPRECATED L{property_RO}. 

 

@arg method: The C{property_RO.fget} method (C{callable}). 

 

@return: The B{C{method}} DEPRECATED. 

''' 

return _deprecated_RO(method, property_RO) 

 

 

def _deprecated_RO(method, _RO): 

'''(INTERNAL) Create a DEPRECATED C{property_RO} or C{Property_RO}. 

''' 

doc = _docof(method) 

 

if _W_DEV: 

 

class _Deprecated_RO(_PropertyBase): 

__doc__ = doc 

 

def __init__(self, method): 

_PropertyBase.__init__(self, method, self._fget, self._fset_error, doc=doc) 

 

def _fget(self, inst): # PYCHOK no cover 

q = _qualified(inst, self.name) 

_throwarning(_RO.__name__, q, doc) 

return self.method(inst) 

 

return _Deprecated_RO(method) 

else: # PYCHOK no cover 

return _RO(method, doc=doc) 

 

 

def DeprecationWarnings(): 

'''Have any C{DeprecationWarning}s been reported or raised? 

 

@return: The number of C{DeprecationWarning}s (C{int}) so 

far or C{None} if not enabled. 

 

@note: To get C{DeprecationWarning}s if any, run C{python} 

with env var C{PYGEODESY_WARNINGS} set to a non-empty 

string I{AND} use C{python[3]} command line option 

C{-X dev}, C{-W always} or C{-W error}, etc. 

''' 

return _Warnings if _W_DEV else None 

 

 

def _docof(obj): 

'''(INTERNAL) Get uniform DEPRECATED __doc__ string. 

''' 

try: 

d = obj.__doc__.strip() 

i = d.find(_DEPRECATED_) 

except AttributeError: 

i = -1 

return _DOT_(_DEPRECATED_, NN) if i < 0 else d[i:] 

 

 

def _qualified(inst, name): 

'''(INTERNAL) Fully qualify a name. 

''' 

# _DOT_(inst.classname, name), not _DOT_(inst.named4, name) 

c = inst.__class__ 

q = _DOT_(c.__module__, c.__name__, name) 

return q 

 

 

def _throwarning(kind, name, doc, **stacklevel): # stacklevel=3 

'''(INTERNAL) Report or raise a C{DeprecationWarning}. 

''' 

from warnings import warn 

 

line = doc.split(_DNL_, 1)[0].strip() 

name = _MODS.streprs.Fmt.CURLY(L=name) 

text = _SPACE_(kind, name, _has_been_, *line.split()) 

kwds = _xkwds(stacklevel, stacklevel=3) 

# XXX invoke warn or raise DeprecationWarning(text) 

warn(text, category=DeprecationWarning, **kwds) 

 

global _Warnings 

_Warnings += 1 

 

# **) MIT License 

# 

# Copyright (C) 2016-2022 -- 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.