import functools
import inspect
import weakref
from typing import Iterable
[docs]def lru_cache(*lru_args, **lru_kwargs):
"""Method-safe LRU cache; https://stackoverflow.com/a/33672499"""
def decorator(func):
@functools.wraps(func)
def wrapped_func(self, *args, **kwargs):
# We're storing the wrapped method inside the instance. If we had
# a strong reference to self the instance would never die.
self_weak = weakref.ref(self)
@functools.wraps(func)
@functools.lru_cache(*lru_args, **lru_kwargs)
def cached_method(*args, **kwargs):
return func(self_weak(), *args, **kwargs)
setattr(self, func.__name__, cached_method)
return cached_method(*args, **kwargs)
return wrapped_func
return decorator
[docs]def validate(**validate_kwargs):
"""Validate arguments to a function with validator-like functions.
def is_float(value):
if not isinstance(value, float):
raise ValueError
@validate(a=is_float)
def add(a, b):
return a + b
# this will fail
add(3, 4.4)
# this is fine
add(1.1, 2) # b is not checked
"""
def decorator(func):
sig = inspect.signature(func)
@functools.wraps(func)
def wrapper(*args, **kwargs):
passed_values = sig.bind(*args, **kwargs).arguments
for arg, value in passed_values.items():
if arg in validate_kwargs.keys():
if isinstance(validate_kwargs[arg], Iterable):
for validator in validate_kwargs[arg]:
validator(value)
else:
validate_kwargs[arg](value)
res = func(*args, **kwargs)
return res
return wrapper
return decorator