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, Lock
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):
75 self._serializer = PickleSerializer()
76 self.shared_memory = self._get_or_create_memory_block(name, size)
77 self._ensure_memory_initialization()
79 def _get_or_create_memory_block(
80 self, name: str, size: int
81 ) -> shared_memory.SharedMemory:
83 return shared_memory.SharedMemory(name=name)
84 except FileNotFoundError:
85 return shared_memory.SharedMemory(name=name, create=True, size=size)
87 def _ensure_memory_initialization(self):
89 bytes(self.shared_memory.buf).split(SharedDict.NULL_BYTE, 1)[0] == b''
94 def close(self) -> None:
95 if not hasattr(self, 'shared_memory'):
97 self.shared_memory.close()
99 def cleanup(self) -> None:
100 if not hasattr(self, 'shared_memory'):
102 self.shared_memory.unlink()
104 @synchronized(MPLOCK)
105 def clear(self) -> None:
106 self._save_memory({})
108 def popitem(self, last: Optional[bool] = None) -> Any:
109 with self._modify_db() as db:
112 @synchronized(MPLOCK)
114 def _modify_db(self) -> Generator:
115 db = self._read_memory()
117 self._save_memory(db)
119 def __getitem__(self, key: str) -> Any:
120 return self._read_memory()[key]
122 def __setitem__(self, key: str, value: Any) -> None:
123 with self._modify_db() as db:
126 def __len__(self) -> int:
127 return len(self._read_memory())
129 def __delitem__(self, key: str) -> None:
130 with self._modify_db() as db:
133 def __iter__(self) -> Iterator:
134 return iter(self._read_memory())
136 def __reversed__(self):
137 return reversed(self._read_memory())
139 def __del__(self) -> None:
142 def __contains__(self, key: str) -> bool:
143 return key in self._read_memory()
145 def __eq__(self, other: Any) -> bool:
146 return self._read_memory() == other
148 def __ne__(self, other: Any) -> bool:
149 return self._read_memory() != other
151 def __str__(self) -> str:
152 return str(self._read_memory())
154 def __repr__(self) -> str:
155 return repr(self._read_memory())
157 def get(self, key: str, default: Optional[Any] = None) -> Any:
158 return self._read_memory().get(key, default)
160 def keys(self) -> KeysView[Any]:
161 return self._read_memory().keys()
163 def values(self) -> ValuesView[Any]:
164 return self._read_memory().values()
166 def items(self) -> ItemsView:
167 return self._read_memory().items()
169 def pop(self, key: str, default: Optional[Any] = None):
170 with self._modify_db() as db:
173 return db.pop(key, default)
175 def update(self, other=(), /, **kwds):
176 with self._modify_db() as db:
177 db.update(other, **kwds)
179 def setdefault(self, key: str, default: Optional[Any] = None):
180 with self._modify_db() as db:
181 return db.setdefault(key, default)
183 def _save_memory(self, db: Dict[str, Any]) -> None:
184 data = self._serializer.dumps(db)
186 self.shared_memory.buf[: len(data)] = data
187 except ValueError as exc:
188 raise ValueError("exceeds available storage") from exc
190 def _read_memory(self) -> Dict[str, Any]:
191 return self._serializer.loads(self.shared_memory.buf.tobytes())
194 if __name__ == '__main__':