27 lines
835 B
Python
27 lines
835 B
Python
import functools
|
|
|
|
|
|
def method_cache(fn):
|
|
"""
|
|
A decorator for instance based caching.
|
|
|
|
Unlike lru_cache / memoization, this allows us to not have to have the
|
|
instance itself be hashable - only the arguments must be so.
|
|
|
|
The cache is stored as a dictionary in a private attribute on the instance
|
|
with the name ``_cache_{func_name}``.
|
|
|
|
"""
|
|
cache_name = f'_cache_{fn.__name__}'
|
|
|
|
@functools.wraps(fn)
|
|
def cached_method(self, *args, **kwargs):
|
|
cache = getattr(self, cache_name, None)
|
|
if cache is None:
|
|
cache = {}
|
|
object.__setattr__(self, cache_name, cache)
|
|
cache_key = hash(args + tuple(kwargs.items()))
|
|
if cache_key not in cache:
|
|
cache[cache_key] = fn(self, *args, **kwargs)
|
|
return cache[cache_key]
|
|
return cached_method
|