"""Database management."""
+from __future__ import annotations
from os.path import isfile
from difflib import Differ
from sqlite3 import connect as sql_connect, Cursor, Row
-from typing import Any, Dict
+from typing import Any, Self, TypeVar, Generic
from plomtask.exceptions import HandledException
PATH_DB_SCHEMA = 'scripts/init.sql'
def __init__(self, db_file: DatabaseFile) -> None:
self.file = db_file
self.conn = sql_connect(self.file.path)
- self.cached_todos: Dict[int, Any] = {}
- self.cached_days: Dict[str, Any] = {}
- self.cached_process_steps: Dict[int, Any] = {}
- self.cached_processes: Dict[int, Any] = {}
- self.cached_conditions: Dict[int, Any] = {}
def commit(self) -> None:
"""Commit SQL transaction."""
return '(' + ','.join(['?'] * len(values)) + ')'
-class BaseModel:
+X = TypeVar('X', int, str)
+T = TypeVar('T', bound='BaseModel[Any]')
+
+
+class BaseModel(Generic[X]):
"""Template for most of the models we use/derive from the DB."""
table_name = ''
to_save: list[str] = []
- id_: None | int | str
- id_type: type[Any] = int
+ id_: None | X
+ cache_: dict[X, Self] = {}
@classmethod
- def from_table_row(cls, db_conn: DatabaseConnection,
- row: Row | list[Any]) -> Any:
+ def from_table_row(cls: type[T],
+ # pylint: disable=unused-argument
+ db_conn: DatabaseConnection,
+ row: Row | list[Any]) -> T:
"""Make from DB row, write to DB cache."""
obj = cls(*row)
- assert isinstance(obj.id_, cls.id_type)
- cache = getattr(db_conn, f'cached_{cls.table_name}')
- cache[obj.id_] = obj
+ obj.cache()
return obj
@classmethod
def _by_id(cls,
db_conn: DatabaseConnection,
- id_: int | str) -> tuple[Any, bool]:
+ id_: X) -> tuple[Self | None, bool]:
"""Return instance found by ID, or None, and if from cache or not."""
from_cache = False
- obj = None
- cache = getattr(db_conn, f'cached_{cls.table_name}')
- if id_ in cache.keys():
- obj = cache[id_]
+ obj = cls.get_cached(id_)
+ if obj:
from_cache = True
else:
for row in db_conn.row_where(cls.table_name, 'id', id_):
obj = cls.from_table_row(db_conn, row)
- cache[id_] = obj
+ assert isinstance(obj, cls)
+ obj.cache()
break
return obj, from_cache
if (id_ is not None) and id_ < 1:
msg = f'illegal {self.__class__.__name__} ID, must be >=1: {id_}'
raise HandledException(msg)
- self.id_ = id_
+ self.id_ = id_ # type: ignore[assignment]
def save_core(self, db_conn: DatabaseConnection,
update_with_lastrowid: bool = True) -> None:
cursor = db_conn.exec(f'REPLACE INTO {table_name} VALUES {q_marks}',
values)
if update_with_lastrowid:
- self.id_ = cursor.lastrowid
- cache = getattr(db_conn, f'cached_{table_name}')
- cache[self.id_] = self
+ self.id_ = cursor.lastrowid # type: ignore[assignment]
+ self.cache()
+
+ @classmethod
+ def get_cached(cls: type[T], id_: X) -> T | None:
+ """Get object of id_ from class's cache, or None if not found."""
+ # pylint: disable=consider-iterating-dictionary
+ if id_ in cls.cache_.keys():
+ obj = cls.cache_[id_]
+ assert isinstance(obj, cls)
+ return obj
+ return None
+
+ def cache(self) -> None:
+ """Update object in class's cache."""
+ if self.id_ is None:
+ raise HandledException('Cannot cache object without ID.')
+ self.__class__.cache_[self.id_] = self
+
+ def uncache(self) -> None:
+ """Remove self from cache."""
+ if self.id_ is None:
+ raise HandledException('Cannot un-cache object without ID.')
+ del self.__class__.cache_[self.id_]
+
+ @classmethod
+ def empty_cache(cls) -> None:
+ """Empty class's cache."""
+ cls.cache_ = {}