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
45 from decorator_utils import synchronized
48 class PickleSerializer:
49 def dumps(self, obj: dict) -> bytes:
51 return pickle.dumps(obj, pickle.HIGHEST_PROTOCOL)
52 except pickle.PicklingError as e:
55 def loads(self, data: bytes) -> dict:
57 return pickle.loads(data)
58 except pickle.UnpicklingError as e:
62 # TODO: protobuf serializer?
65 class SharedDict(object):
72 size_bytes: Optional[int] = None,
76 self._serializer = PickleSerializer()
77 assert size_bytes is None or size_bytes > 0
78 self.shared_memory = self._get_or_create_memory_block(name, size_bytes)
79 self._ensure_memory_initialization()
85 def _get_or_create_memory_block(
88 size_bytes: Optional[int] = None,
89 ) -> shared_memory.SharedMemory:
91 return shared_memory.SharedMemory(name=name)
92 except FileNotFoundError:
93 assert size_bytes is not None
94 return shared_memory.SharedMemory(name=name, create=True, size=size_bytes)
96 def _ensure_memory_initialization(self):
98 bytes(self.shared_memory.buf).split(SharedDict.NULL_BYTE, 1)[0] == b''
103 def close(self) -> None:
104 if not hasattr(self, 'shared_memory'):
106 self.shared_memory.close()
108 def cleanup(self) -> None:
109 if not hasattr(self, 'shared_memory'):
111 self.shared_memory.unlink()
113 def clear(self) -> None:
114 self._save_memory({})
116 def popitem(self, last: Optional[bool] = None) -> Any:
117 with self._modify_db() as db:
121 def _modify_db(self) -> Generator:
122 with SharedDict.MPLOCK:
123 db = self._read_memory()
125 self._save_memory(db)
127 def __getitem__(self, key: str) -> Any:
128 return self._read_memory()[key]
130 def __setitem__(self, key: str, value: Any) -> None:
131 with self._modify_db() as db:
134 def __len__(self) -> int:
135 return len(self._read_memory())
137 def __delitem__(self, key: str) -> None:
138 with self._modify_db() as db:
141 def __iter__(self) -> Iterator:
142 return iter(self._read_memory())
144 def __reversed__(self):
145 return reversed(self._read_memory())
147 def __del__(self) -> None:
150 def __contains__(self, key: str) -> bool:
151 return key in self._read_memory()
153 def __eq__(self, other: Any) -> bool:
154 return self._read_memory() == other
156 def __ne__(self, other: Any) -> bool:
157 return self._read_memory() != other
159 def __str__(self) -> str:
160 return str(self._read_memory())
162 def __repr__(self) -> str:
163 return repr(self._read_memory())
165 def get(self, key: str, default: Optional[Any] = None) -> Any:
166 return self._read_memory().get(key, default)
168 def keys(self) -> KeysView[Any]:
169 return self._read_memory().keys()
171 def values(self) -> ValuesView[Any]:
172 return self._read_memory().values()
174 def items(self) -> ItemsView:
175 return self._read_memory().items()
177 def pop(self, key: str, default: Optional[Any] = None):
178 with self._modify_db() as db:
181 return db.pop(key, default)
183 def update(self, other=(), /, **kwds):
184 with self._modify_db() as db:
185 db.update(other, **kwds)
187 def setdefault(self, key: str, default: Optional[Any] = None):
188 with self._modify_db() as db:
189 return db.setdefault(key, default)
191 def _save_memory(self, db: Dict[str, Any]) -> None:
192 with SharedDict.MPLOCK:
193 data = self._serializer.dumps(db)
195 self.shared_memory.buf[: len(data)] = data
196 except ValueError as exc:
197 raise ValueError("exceeds available storage") from exc
199 def _read_memory(self) -> Dict[str, Any]:
200 with SharedDict.MPLOCK:
201 return self._serializer.loads(self.shared_memory.buf.tobytes())
204 if __name__ == '__main__':