HPI/my/core/sqlite.py
Kian-Meng Ang d2ef23fcb4 docs: fix typos
found via `codespell -L copie,datas,pres,fo,tooks,noo,ue,ket,frop`
2023-03-27 03:02:35 +01:00

130 lines
5.1 KiB
Python

from .common import assert_subpackage; assert_subpackage(__name__)
from contextlib import contextmanager
from pathlib import Path
import shutil
import sqlite3
from tempfile import TemporaryDirectory
from typing import Tuple, Any, Iterator, Callable, Optional, Union
from .common import PathIsh, assert_never
from .compat import Literal
def sqlite_connect_immutable(db: PathIsh) -> sqlite3.Connection:
return sqlite3.connect(f'file:{db}?immutable=1', uri=True)
def test_sqlite_connect_immutable(tmp_path: Path) -> None:
db = str(tmp_path / 'db.sqlite')
with sqlite3.connect(db) as conn:
conn.execute('CREATE TABLE testtable (col)')
import pytest # type: ignore
with pytest.raises(sqlite3.OperationalError, match='readonly database'):
with sqlite_connect_immutable(db) as conn:
conn.execute('DROP TABLE testtable')
# succeeds without immutable
with sqlite3.connect(db) as conn:
conn.execute('DROP TABLE testtable')
SqliteRowFactory = Callable[[sqlite3.Cursor, sqlite3.Row], Any]
def dict_factory(cursor, row):
fields = [column[0] for column in cursor.description]
return {key: value for key, value in zip(fields, row)}
Factory = Union[SqliteRowFactory, Literal['row', 'dict']]
@contextmanager
def sqlite_connection(db: PathIsh, *, immutable: bool=False, row_factory: Optional[Factory]=None) -> Iterator[sqlite3.Connection]:
dbp = f'file:{db}'
# https://www.sqlite.org/draft/uri.html#uriimmutable
if immutable:
# assert results in nicer error than sqlite3.OperationalError
assert Path(db).exists(), db
dbp = f'{dbp}?immutable=1'
row_factory_: Any = None
if row_factory is not None:
if callable(row_factory):
row_factory_ = row_factory
elif row_factory == 'row':
row_factory_ = sqlite3.Row
elif row_factory == 'dict':
row_factory_ = dict_factory
else:
assert_never()
conn = sqlite3.connect(dbp, uri=True)
try:
conn.row_factory = row_factory_
with conn:
yield conn
finally:
# Connection context manager isn't actually closing the connection, only keeps transaction
conn.close()
# TODO come up with a better name?
# NOTE: this is tested by tests/sqlite.py::test_sqlite_read_with_wal
def sqlite_copy_and_open(db: PathIsh) -> sqlite3.Connection:
"""
'Snapshots' database and opens by making a deep copy of it including journal/WAL files
"""
dp = Path(db)
# TODO make atomic/check mtimes or something
dest = sqlite3.connect(':memory:')
with TemporaryDirectory() as td:
tdir = Path(td)
# shm should be recreated from scratch -- safer not to copy perhaps
tocopy = [dp] + [p for p in dp.parent.glob(dp.name + '-*') if not p.name.endswith('-shm')]
for p in tocopy:
shutil.copy(p, tdir / p.name)
with sqlite3.connect(str(tdir / dp.name)) as conn:
from .compat import sqlite_backup
sqlite_backup(source=conn, dest=dest)
conn.close()
return dest
# NOTE hmm, so this kinda works
# V = TypeVar('V', bound=Tuple[Any, ...])
# def select(cols: V, rest: str, *, db: sqlite3.Connection) -> Iterator[V]:
# but sadly when we pass columns (Tuple[str, ...]), it seems to bind this type to V?
# and then the return type ends up as Iterator[Tuple[str, ...]], which isn't desirable :(
# a bit annoying to have this copy-pasting, but hopefully not a big issue
from typing import overload
@overload
def select(cols: Tuple[str ], rest: str, *, db: sqlite3.Connection) -> \
Iterator[Tuple[Any ]]: ...
@overload
def select(cols: Tuple[str, str ], rest: str, *, db: sqlite3.Connection) -> \
Iterator[Tuple[Any, Any ]]: ...
@overload
def select(cols: Tuple[str, str, str ], rest: str, *, db: sqlite3.Connection) -> \
Iterator[Tuple[Any, Any, Any ]]: ...
@overload
def select(cols: Tuple[str, str, str, str ], rest: str, *, db: sqlite3.Connection) -> \
Iterator[Tuple[Any, Any, Any, Any ]]: ...
@overload
def select(cols: Tuple[str, str, str, str, str ], rest: str, *, db: sqlite3.Connection) -> \
Iterator[Tuple[Any, Any, Any, Any, Any ]]: ...
@overload
def select(cols: Tuple[str, str, str, str, str, str ], rest: str, *, db: sqlite3.Connection) -> \
Iterator[Tuple[Any, Any, Any, Any, Any, Any ]]: ...
@overload
def select(cols: Tuple[str, str, str, str, str, str, str ], rest: str, *, db: sqlite3.Connection) -> \
Iterator[Tuple[Any, Any, Any, Any, Any, Any, Any ]]: ...
@overload
def select(cols: Tuple[str, str, str, str, str, str, str, str], rest: str, *, db: sqlite3.Connection) -> \
Iterator[Tuple[Any, Any, Any, Any, Any, Any, Any, Any]]: ...
def select(cols, rest, *, db):
# db arg is last cause that results in nicer code formatting..
return db.execute('SELECT ' + ','.join(cols) + ' ' + rest)