-#!/usr/bin/env python3
-
-import pickle
-from typing import Any, Mapping
-
-import file_utils
-
-
-class PersistentState(object):
- """
- An object that behaves like a persistent hash map; it can be
- accessed to store key-value pairs but also saved to disk and read
- back from disk easily.
-
- """
- def __init__(self, filename: str, *, max_age_sec: int = None):
- self.filename = filename
- if file_utils.does_file_exist(self.filename):
- if max_age_sec is not None:
- age = file_utils.get_file_mtime_age_seconds(self.filename)
- if age < max_age_sec:
- self.state = self.load()
- else:
- self.state = {}
- else:
- self.state = self.load()
- else:
- self.state = {}
-
- def __getitem__(self, key: str) -> Any:
- return self.state.get(key, "")
-
- def __setitem__(self, key: str, value: Any):
- self.state[key] = value
-
- def __delitem__(self, key: str):
- del self.state[key]
-
- def __iter__(self):
- return iter(self.state)
-
- def __len__(self):
- return len(self.state)
-
- def save(self) -> None:
- with open(self.filename, 'wb') as f:
- pickle.dump(self.state, f, pickle.HIGHEST_PROTOCOL)
-
- def load(self) -> Mapping[str, Any]:
- with open(self.filename, 'rb') as f:
- return(pickle.load(f))