6 Copyright (c) 2020 LuizaLabs
7 Additions/Modifications 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 multiprocessing import RLock, shared_memory
45 class PickleSerializer:
46 def dumps(self, obj: dict) -> bytes:
48 return pickle.dumps(obj, pickle.HIGHEST_PROTOCOL)
49 except pickle.PicklingError as e:
52 def loads(self, data: bytes) -> dict:
54 return pickle.loads(data)
55 except pickle.UnpicklingError as e:
59 # TODO: protobuf serializer?
62 class SharedDict(object):
69 size_bytes: Optional[int] = None,
73 self._serializer = PickleSerializer()
74 assert size_bytes is None or size_bytes > 0
75 self.shared_memory = self._get_or_create_memory_block(name, size_bytes)
76 self._ensure_memory_initialization()
82 def _get_or_create_memory_block(
85 size_bytes: Optional[int] = None,
86 ) -> shared_memory.SharedMemory:
88 return shared_memory.SharedMemory(name=name)
89 except FileNotFoundError:
90 assert size_bytes is not None
91 return shared_memory.SharedMemory(name=name, create=True, size=size_bytes)
93 def _ensure_memory_initialization(self):
94 memory_is_empty = bytes(self.shared_memory.buf).split(SharedDict.NULL_BYTE, 1)[0] == b''
98 def close(self) -> None:
99 if not hasattr(self, 'shared_memory'):
101 self.shared_memory.close()
103 def cleanup(self) -> None:
104 if not hasattr(self, 'shared_memory'):
106 with SharedDict.MPLOCK:
107 self.shared_memory.unlink()
109 def clear(self) -> None:
110 self._save_memory({})
112 def popitem(self, last: Optional[bool] = None) -> Any:
113 with self._modify_db() as db:
117 def _modify_db(self) -> Generator:
118 with SharedDict.MPLOCK:
119 db = self._read_memory()
121 self._save_memory(db)
123 def __getitem__(self, key: str) -> Any:
124 return self._read_memory()[key]
126 def __setitem__(self, key: str, value: Any) -> None:
127 with self._modify_db() as db:
130 def __len__(self) -> int:
131 return len(self._read_memory())
133 def __delitem__(self, key: str) -> None:
134 with self._modify_db() as db:
137 def __iter__(self) -> Iterator:
138 return iter(self._read_memory())
140 def __reversed__(self):
141 return reversed(self._read_memory())
143 def __del__(self) -> None:
146 def __contains__(self, key: str) -> bool:
147 return key in self._read_memory()
149 def __eq__(self, other: Any) -> bool:
150 return self._read_memory() == other
152 def __ne__(self, other: Any) -> bool:
153 return self._read_memory() != other
155 def __str__(self) -> str:
156 return str(self._read_memory())
158 def __repr__(self) -> str:
159 return repr(self._read_memory())
161 def get(self, key: str, default: Optional[Any] = None) -> Any:
162 return self._read_memory().get(key, default)
164 def keys(self) -> KeysView[Any]:
165 return self._read_memory().keys()
167 def values(self) -> ValuesView[Any]:
168 return self._read_memory().values()
170 def items(self) -> ItemsView:
171 return self._read_memory().items()
173 def pop(self, key: str, default: Optional[Any] = None):
174 with self._modify_db() as db:
177 return db.pop(key, default)
179 def update(self, other=(), /, **kwds):
180 with self._modify_db() as db:
181 db.update(other, **kwds)
183 def setdefault(self, key: str, default: Optional[Any] = None):
184 with self._modify_db() as db:
185 return db.setdefault(key, default)
187 def _save_memory(self, db: Dict[str, Any]) -> None:
188 with SharedDict.MPLOCK:
189 data = self._serializer.dumps(db)
191 self.shared_memory.buf[: len(data)] = data
192 except ValueError as exc:
193 raise ValueError("exceeds available storage") from exc
195 def _read_memory(self) -> Dict[str, Any]:
196 with SharedDict.MPLOCK:
197 return self._serializer.loads(self.shared_memory.buf.tobytes())
200 if __name__ == '__main__':