115 lines
3.1 KiB
Python
115 lines
3.1 KiB
Python
# -*- coding: utf-8 -*-
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# Part of Odoo, Flectra. See LICENSE file for full copyright and licensing details.
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__all__ = ['synchronized', 'lazy_classproperty', 'lazy_property',
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'classproperty', 'conditional']
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from functools import wraps
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from inspect import getsourcefile
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class lazy_property(object):
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""" Decorator for a lazy property of an object, i.e., an object attribute
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that is determined by the result of a method call evaluated once. To
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reevaluate the property, simply delete the attribute on the object, and
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get it again.
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"""
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def __init__(self, fget):
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self.fget = fget
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def __get__(self, obj, cls):
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if obj is None:
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return self
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value = self.fget(obj)
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setattr(obj, self.fget.__name__, value)
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return value
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@property
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def __doc__(self):
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return self.fget.__doc__
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@staticmethod
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def reset_all(obj):
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""" Reset all lazy properties on the instance `obj`. """
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cls = type(obj)
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obj_dict = vars(obj)
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for name in list(obj_dict):
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if isinstance(getattr(cls, name, None), lazy_property):
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obj_dict.pop(name)
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class lazy_classproperty(lazy_property):
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""" Similar to :class:`lazy_property`, but for classes. """
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def __get__(self, obj, cls):
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val = self.fget(cls)
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setattr(cls, self.fget.__name__, val)
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return val
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def conditional(condition, decorator):
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""" Decorator for a conditionally applied decorator.
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Example:
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@conditional(get_config('use_cache'), ormcache)
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def fn():
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pass
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"""
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if condition:
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return decorator
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else:
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return lambda fn: fn
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def synchronized(lock_attr='_lock'):
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def decorator(func):
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@wraps(func)
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def wrapper(self, *args, **kwargs):
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lock = getattr(self, lock_attr)
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try:
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lock.acquire()
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return func(self, *args, **kwargs)
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finally:
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lock.release()
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return wrapper
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return decorator
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def frame_codeinfo(fframe, back=0):
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""" Return a (filename, line) pair for a previous frame .
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@return (filename, lineno) where lineno is either int or string==''
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"""
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try:
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if not fframe:
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return "<unknown>", ''
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for i in range(back):
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fframe = fframe.f_back
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try:
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fname = getsourcefile(fframe)
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except TypeError:
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fname = '<builtin>'
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lineno = fframe.f_lineno or ''
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return fname, lineno
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except Exception:
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return "<unknown>", ''
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def compose(a, b):
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""" Composes the callables ``a`` and ``b``. ``compose(a, b)(*args)`` is
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equivalent to ``a(b(*args))``.
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Can be used as a decorator by partially applying ``a``::
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@partial(compose, a)
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def b():
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...
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"""
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@wraps(b)
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def wrapper(*args, **kwargs):
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return a(b(*args, **kwargs))
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return wrapper
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class _ClassProperty(property):
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def __get__(self, cls, owner):
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return self.fget.__get__(None, owner)()
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def classproperty(func):
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return _ClassProperty(classmethod(func))
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