codekingpro/portable-devtools

1# sql/_py_util.py
2# Copyright (C) 2005-2026 the SQLAlchemy authors and contributors
3# <see AUTHORS file>
4#
5# This module is part of SQLAlchemy and is released under
6# the MIT License: https://www.opensource.org/licenses/mit-license.php
7
8from __future__ import annotations
9
10import typing
11from typing import Any
12from typing import Dict
13from typing import Tuple
14from typing import Union
15
16from ..util.typing import Literal
17
18if typing.TYPE_CHECKING:
19    from .cache_key import CacheConst
20
21
22class prefix_anon_map(Dict[str, str]):
23    """A map that creates new keys for missing key access.
24
25    Considers keys of the form "<ident> <name>" to produce
26    new symbols "<name>_<index>", where "index" is an incrementing integer
27    corresponding to <name>.
28
29    Inlines the approach taken by :class:`sqlalchemy.util.PopulateDict` which
30    is otherwise usually used for this type of operation.
31
32    """
33
34    def __missing__(self, key: str) -> str:
35        (ident, derived) = key.split(" ", 1)
36        anonymous_counter = self.get(derived, 1)
37        self[derived] = anonymous_counter + 1  # type: ignore
38        value = f"{derived}_{anonymous_counter}"
39        self[key] = value
40        return value
41
42
43class cache_anon_map(
44    Dict[Union[int, "Literal[CacheConst.NO_CACHE]"], Union[Literal[True], str]]
45):
46    """A map that creates new keys for missing key access.
47
48    Produces an incrementing sequence given a series of unique keys.
49
50    This is similar to the compiler prefix_anon_map class although simpler.
51
52    Inlines the approach taken by :class:`sqlalchemy.util.PopulateDict` which
53    is otherwise usually used for this type of operation.
54
55    """
56
57    _index = 0
58
59    def get_anon(self, object_: Any) -> Tuple[str, bool]:
60        idself = id(object_)
61        if idself in self:
62            s_val = self[idself]
63            assert s_val is not True
64            return s_val, True
65        else:
66            # inline of __missing__
67            self[idself] = id_ = str(self._index)
68            self._index += 1
69
70            return id_, False
71
72    def __missing__(self, key: int) -> str:
73        self[key] = val = str(self._index)
74        self._index += 1
75        return val
76