| 1 | import threading, pickle, inspect, atexit, weakref |
| 2 | from . import db, index, cache |
| 3 | from .db import txnfun |
| 4 | |
| 5 | __all__ = ["environment", "datastore", "autostore"] |
| 6 | |
| 7 | class environment(object): |
| 8 | def __init__(self, *, path=None, getpath=None, recover=False): |
| 9 | if path is not None: |
| 10 | self.path = path |
| 11 | self.getpath = None |
| 12 | else: |
| 13 | self.path = None |
| 14 | self.getpath = getpath |
| 15 | self.recover = recover |
| 16 | self.lk = threading.Lock() |
| 17 | self.bk = None |
| 18 | |
| 19 | def __call__(self): |
| 20 | with self.lk: |
| 21 | if self.bk is None: |
| 22 | if self.path is None: |
| 23 | self.path = self.getpath() |
| 24 | self.bk = db.environment(self.path, recover=self.recover) |
| 25 | atexit.register(self.close) |
| 26 | return self.bk |
| 27 | |
| 28 | def close(self): |
| 29 | with self.lk: |
| 30 | if self.bk is not None: |
| 31 | atexit.unregister(self.close) |
| 32 | self.bk.close() |
| 33 | self.bk = None |
| 34 | |
| 35 | class storedesc(object): |
| 36 | pass |
| 37 | |
| 38 | def storedescs(obj): |
| 39 | t = type(obj) |
| 40 | ret = t.__dict__.get("__didex_attr") |
| 41 | if ret is None: |
| 42 | ret = [] |
| 43 | for st in inspect.getmro(t): |
| 44 | for nm, val in st.__dict__.items(): |
| 45 | if isinstance(val, storedesc): |
| 46 | ret.append((nm, val)) |
| 47 | t.__didex_attr = ret |
| 48 | return ret |
| 49 | |
| 50 | class icache(object): |
| 51 | def __init__(self): |
| 52 | self.d = weakref.WeakKeyDictionary() |
| 53 | |
| 54 | def __getitem__(self, key): |
| 55 | obj, idx = key |
| 56 | return self.d[obj][idx] |
| 57 | def __setitem__(self, key, val): |
| 58 | obj, idx = key |
| 59 | if obj in self.d: |
| 60 | self.d[obj][idx] = val |
| 61 | else: |
| 62 | self.d[obj] = {idx: val} |
| 63 | def __delitem__(self, key): |
| 64 | obj, idx = key |
| 65 | del self.d[obj][idx] |
| 66 | def get(self, key, default=None): |
| 67 | obj, idx = key |
| 68 | if obj not in self.d: |
| 69 | return default |
| 70 | return self.d[obj].get(idx, default) |
| 71 | |
| 72 | class datastore(object): |
| 73 | def __init__(self, name, *, env=None, path=".", ncache=None, codec=None): |
| 74 | self.name = name |
| 75 | self.lk = threading.Lock() |
| 76 | if env: |
| 77 | self.env = env |
| 78 | else: |
| 79 | self.env = environment(path=path) |
| 80 | self._db = None |
| 81 | if ncache is None: |
| 82 | ncache = cache.cache() |
| 83 | if codec is not None: |
| 84 | self._encode, self._decode = codec |
| 85 | self.cache = ncache |
| 86 | self.cache.load = self._load |
| 87 | self.icache = icache() |
| 88 | |
| 89 | def db(self): |
| 90 | with self.lk: |
| 91 | if self._db is None: |
| 92 | self._db = self.env().db(self.name) |
| 93 | return self._db |
| 94 | |
| 95 | def _decode(self, data): |
| 96 | try: |
| 97 | return pickle.loads(data) |
| 98 | except: |
| 99 | raise KeyError(id, "could not unpickle data") |
| 100 | |
| 101 | def _encode(self, obj): |
| 102 | return pickle.dumps(obj) |
| 103 | |
| 104 | @txnfun(lambda self: self.db().env) |
| 105 | def _load(self, id, *, tx): |
| 106 | loaded = self._decode(self.db().get(id, tx=tx)) |
| 107 | if hasattr(loaded, "__didex_loaded__"): |
| 108 | loaded.__didex_loaded__(self, id) |
| 109 | for nm, attr in storedescs(loaded): |
| 110 | attr.loaded(id, loaded, tx) |
| 111 | return loaded |
| 112 | |
| 113 | def get(self, id, *, load=True): |
| 114 | return self.cache.get(id, load=load) |
| 115 | |
| 116 | @txnfun(lambda self: self.db().env) |
| 117 | def register(self, obj, *, tx): |
| 118 | id = self.db().add(self._encode(obj), tx=tx) |
| 119 | for nm, attr in storedescs(obj): |
| 120 | attr.register(id, obj, tx) |
| 121 | self.cache.put(id, obj) |
| 122 | return id |
| 123 | |
| 124 | @txnfun(lambda self: self.db().env) |
| 125 | def unregister(self, id, *, vfy=None, tx): |
| 126 | obj = self.get(id) |
| 127 | if vfy is not None and obj is not vfy: |
| 128 | raise RuntimeError("object identity crisis: " + str(vfy) + " is not cached object " + obj) |
| 129 | for nm, attr in storedescs(obj): |
| 130 | attr.unregister(id, obj, tx) |
| 131 | self.db().remove(id, tx=tx) |
| 132 | self.cache.remove(id) |
| 133 | |
| 134 | @txnfun(lambda self: self.db().env) |
| 135 | def update(self, id, *, vfy=None, tx): |
| 136 | obj = self.get(id, load=False) |
| 137 | if vfy is not None and obj is not vfy: |
| 138 | raise RuntimeError("object identity crisis: " + str(vfy) + " is not cached object " + obj) |
| 139 | for nm, attr, in storedescs(obj): |
| 140 | attr.update(id, obj, tx) |
| 141 | self.db().replace(id, self._encode(obj), tx=tx) |
| 142 | |
| 143 | class autotype(type): |
| 144 | def __call__(self, *args, **kwargs): |
| 145 | new = super().__call__(*args, **kwargs) |
| 146 | new.id = self.store.register(new) |
| 147 | # XXX? ID is not saved now, but relied upon to be __didex_loaded__ later. |
| 148 | return new |
| 149 | |
| 150 | class autostore(object, metaclass=autotype): |
| 151 | def __init__(self): |
| 152 | self.id = None |
| 153 | |
| 154 | def __didex_loaded__(self, store, id): |
| 155 | assert self.id is None or self.id == id |
| 156 | self.id = id |
| 157 | |
| 158 | def save(self): |
| 159 | self.store.update(self.id, vfy=self) |
| 160 | |
| 161 | def remove(self): |
| 162 | self.store.unregister(self.id, vfy=self) |
| 163 | self.id = None |