"""Helper function(s) for caching results
Copyright 2023 The qLDPC Authors and Infleqtion Inc.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
"""
import functools
import os
from collections.abc import Callable, Hashable
from typing import Any
import diskcache
import platformdirs
[docs]
def get_disk_cache(cache_name: str, *, cache_dir: str | None = None) -> diskcache.Cache:
"""Retrieve a dictionary-like cache object."""
cache_dir = cache_dir or platformdirs.user_cache_dir()
cache_path = os.path.join(cache_dir, cache_name)
return diskcache.Cache(cache_path)
[docs]
def use_disk_cache(
cache_name: str, *, cache_dir: str | None = None
) -> Callable[[Callable[..., Any]], Callable[..., Any]]:
"""Decorator to cache results to disk."""
def decorator(function: Callable[..., Any]) -> Callable[..., Any]:
@functools.wraps(function)
def function_with_cache(*args: Hashable, **kwargs: Hashable) -> Any:
# retrieve results from cache, if available
cache = get_disk_cache(cache_name, cache_dir=cache_dir)
key = args + tuple(kwargs.items())
if key in cache:
return cache[key]
# compute results and save to cache
result = function(*args, **kwargs)
cache[key] = result
return result
return function_with_cache
return decorator