6 Copyright (c) 2020 LuizaLabs
7 Additions Copyright (c) 2022 Scott Gasch
9 Permission is hereby granted, free of charge, to any person obtaining a copy
10 of this software and associated documentation files (the "Software"), to deal
11 in the Software without restriction, including without limitation the rights
12 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
13 copies of the Software, and to permit persons to whom the Software is
14 furnished to do so, subject to the following conditions:
16 The above copyright notice and this permission notice shall be included in all
17 copies or substantial portions of the Software.
19 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
22 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
24 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
27 This class is based on https://github.com/luizalabs/shared-memory-dict
31 from contextlib import contextmanager
32 from functools import wraps
33 from multiprocessing import RLock, shared_memory
34 from typing import Any, Dict, Generator, ItemsView, Iterator, KeysView, Optional, ValuesView
36 from decorator_utils import synchronized
39 class PickleSerializer:
40 def dumps(self, obj: dict) -> bytes:
42 return pickle.dumps(obj, pickle.HIGHEST_PROTOCOL)
43 except pickle.PicklingError as e:
46 def loads(self, data: bytes) -> dict:
48 return pickle.loads(data)
49 except pickle.UnpicklingError as e:
53 # TODO: protobuf serializer?
56 class SharedDict(object):
63 size_bytes: Optional[int] = None,
67 self._serializer = PickleSerializer()
68 assert size_bytes is None or size_bytes > 0
69 self.shared_memory = self._get_or_create_memory_block(name, size_bytes)
70 self._ensure_memory_initialization()
76 def _get_or_create_memory_block(
79 size_bytes: Optional[int] = None,
80 ) -> shared_memory.SharedMemory:
82 return shared_memory.SharedMemory(name=name)
83 except FileNotFoundError:
84 assert size_bytes is not None
85 return shared_memory.SharedMemory(name=name, create=True, size=size_bytes)
87 def _ensure_memory_initialization(self):
88 memory_is_empty = bytes(self.shared_memory.buf).split(SharedDict.NULL_BYTE, 1)[0] == b''
92 def close(self) -> None:
93 if not hasattr(self, 'shared_memory'):
95 self.shared_memory.close()
97 def cleanup(self) -> None:
98 if not hasattr(self, 'shared_memory'):
100 with SharedDict.MPLOCK:
101 self.shared_memory.unlink()
103 def clear(self) -> None:
104 self._save_memory({})
106 def popitem(self, last: Optional[bool] = None) -> Any:
107 with self._modify_db() as db:
111 def _modify_db(self) -> Generator:
112 with SharedDict.MPLOCK:
113 db = self._read_memory()
115 self._save_memory(db)
117 def __getitem__(self, key: str) -> Any:
118 return self._read_memory()[key]
120 def __setitem__(self, key: str, value: Any) -> None:
121 with self._modify_db() as db:
124 def __len__(self) -> int:
125 return len(self._read_memory())
127 def __delitem__(self, key: str) -> None:
128 with self._modify_db() as db:
131 def __iter__(self) -> Iterator:
132 return iter(self._read_memory())
134 def __reversed__(self):
135 return reversed(self._read_memory())
137 def __del__(self) -> None:
140 def __contains__(self, key: str) -> bool:
141 return key in self._read_memory()
143 def __eq__(self, other: Any) -> bool:
144 return self._read_memory() == other
146 def __ne__(self, other: Any) -> bool:
147 return self._read_memory() != other
149 def __str__(self) -> str:
150 return str(self._read_memory())
152 def __repr__(self) -> str:
153 return repr(self._read_memory())
155 def get(self, key: str, default: Optional[Any] = None) -> Any:
156 return self._read_memory().get(key, default)
158 def keys(self) -> KeysView[Any]:
159 return self._read_memory().keys()
161 def values(self) -> ValuesView[Any]:
162 return self._read_memory().values()
164 def items(self) -> ItemsView:
165 return self._read_memory().items()
167 def pop(self, key: str, default: Optional[Any] = None):
168 with self._modify_db() as db:
171 return db.pop(key, default)
173 def update(self, other=(), /, **kwds):
174 with self._modify_db() as db:
175 db.update(other, **kwds)
177 def setdefault(self, key: str, default: Optional[Any] = None):
178 with self._modify_db() as db:
179 return db.setdefault(key, default)
181 def _save_memory(self, db: Dict[str, Any]) -> None:
182 with SharedDict.MPLOCK:
183 data = self._serializer.dumps(db)
185 self.shared_memory.buf[: len(data)] = data
186 except ValueError as exc:
187 raise ValueError("exceeds available storage") from exc
189 def _read_memory(self) -> Dict[str, Any]:
190 with SharedDict.MPLOCK:
191 return self._serializer.loads(self.shared_memory.buf.tobytes())
194 if __name__ == '__main__':