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 shared_memory, RLock
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 self.shared_memory = self._get_or_create_memory_block(name, size_bytes)
78 self._ensure_memory_initialization()
84 def _get_or_create_memory_block(
87 size_bytes: Optional[int] = None,
88 ) -> shared_memory.SharedMemory:
90 return shared_memory.SharedMemory(name=name)
91 except FileNotFoundError:
93 return shared_memory.SharedMemory(name=name, create=True, size=size_bytes)
95 def _ensure_memory_initialization(self):
97 bytes(self.shared_memory.buf).split(SharedDict.NULL_BYTE, 1)[0] == b''
102 def close(self) -> None:
103 if not hasattr(self, 'shared_memory'):
105 self.shared_memory.close()
107 def cleanup(self) -> None:
108 if not hasattr(self, 'shared_memory'):
110 self.shared_memory.unlink()
112 def clear(self) -> None:
113 self._save_memory({})
115 def popitem(self, last: Optional[bool] = None) -> Any:
116 with self._modify_db() as db:
120 def _modify_db(self) -> Generator:
121 with SharedDict.MPLOCK:
122 db = self._read_memory()
124 self._save_memory(db)
126 def __getitem__(self, key: str) -> Any:
127 return self._read_memory()[key]
129 def __setitem__(self, key: str, value: Any) -> None:
130 with self._modify_db() as db:
133 def __len__(self) -> int:
134 return len(self._read_memory())
136 def __delitem__(self, key: str) -> None:
137 with self._modify_db() as db:
140 def __iter__(self) -> Iterator:
141 return iter(self._read_memory())
143 def __reversed__(self):
144 return reversed(self._read_memory())
146 def __del__(self) -> None:
149 def __contains__(self, key: str) -> bool:
150 return key in self._read_memory()
152 def __eq__(self, other: Any) -> bool:
153 return self._read_memory() == other
155 def __ne__(self, other: Any) -> bool:
156 return self._read_memory() != other
158 def __str__(self) -> str:
159 return str(self._read_memory())
161 def __repr__(self) -> str:
162 return repr(self._read_memory())
164 def get(self, key: str, default: Optional[Any] = None) -> Any:
165 return self._read_memory().get(key, default)
167 def keys(self) -> KeysView[Any]:
168 return self._read_memory().keys()
170 def values(self) -> ValuesView[Any]:
171 return self._read_memory().values()
173 def items(self) -> ItemsView:
174 return self._read_memory().items()
176 def pop(self, key: str, default: Optional[Any] = None):
177 with self._modify_db() as db:
180 return db.pop(key, default)
182 def update(self, other=(), /, **kwds):
183 with self._modify_db() as db:
184 db.update(other, **kwds)
186 def setdefault(self, key: str, default: Optional[Any] = None):
187 with self._modify_db() as db:
188 return db.setdefault(key, default)
190 def _save_memory(self, db: Dict[str, Any]) -> None:
191 with SharedDict.MPLOCK:
192 data = self._serializer.dumps(db)
194 self.shared_memory.buf[: len(data)] = data
195 except ValueError as exc:
196 raise ValueError("exceeds available storage") from exc
198 def _read_memory(self) -> Dict[str, Any]:
199 with SharedDict.MPLOCK:
200 return self._serializer.loads(self.shared_memory.buf.tobytes())
203 if __name__ == '__main__':