Dolda2000 GitWeb / didex.git / blame
| Commit | Line | Data |
|---|---|---|
| b080a59c FT |
1 | import threading, weakref |
| 2 | ||
| 3 | class entry(object): | |
| 4 | __slots__ = ["p", "n", "id", "obj", "st", "lk"] | |
| 5 | def __init__(self, id, c): | |
| 6 | self.id = id | |
| 7 | self.obj = None | |
| 8 | self.st = None | |
| 9 | self.lk = None | |
| 10 | self.n = c.mru | |
| 11 | self.p = None | |
| 12 | if c.mru is not None: | |
| 13 | c.mru.p = self | |
| 14 | c.mru = self | |
| 15 | else: | |
| 16 | c.mru = c.lru = self | |
| 17 | c.n += 1 | |
| 18 | ||
| 19 | def relink(self, c): | |
| 20 | if c.mru is self: | |
| 21 | return | |
| 22 | if self.n is not None: | |
| 23 | self.n.p = self.p | |
| 24 | self.p.n = self.n | |
| 25 | if c.lru is self: | |
| 26 | c.lru = self.p | |
| 27 | self.p = None | |
| 28 | self.n = c.mru | |
| 29 | c.mru.p = self | |
| 30 | ||
| 31 | def remove(self, c): | |
| 32 | if self.n is not None: | |
| 33 | self.n.p = self.p | |
| 34 | if self.p is not None: | |
| 35 | self.p.n = self.n | |
| 36 | if c.mru is self: | |
| 37 | c.mru = self.n | |
| 38 | if c.lru is self: | |
| 39 | c.lru = self.p | |
| 40 | c.n -= 1 | |
| 41 | ||
| 42 | class cache(object): | |
| 43 | def __init__(self, *, keep=1000): | |
| 44 | self.keep = keep | |
| 45 | self.cur = {} | |
| 46 | self.mru = self.lru = None | |
| 47 | self.n = 0 | |
| 48 | self.lk = threading.Lock() | |
| 49 | ||
| 50 | def _trim(self, n): | |
| 51 | ent = self.lru | |
| 52 | for i in range(self.n - n): | |
| 53 | if ent.st == "l": | |
| 54 | ent.obj = weakref.ref(ent.obj) | |
| 55 | ent.st = "w" | |
| 56 | elif ent.st == "w" and ent.obj() is None: | |
| 57 | del self.cur[ent.id] | |
| 58 | ent.remove(self) | |
| 59 | ent.st = "r" | |
| 60 | ent = ent.p | |
| 61 | ||
| 62 | def get(self, id, load=True): | |
| 63 | while True: | |
| 64 | with self.lk: | |
| 65 | ent = self.cur.get(id) | |
| 66 | if ent is None: | |
| 67 | if not load: | |
| 68 | raise KeyError(id) | |
| 69 | self.cur[id] = ent = entry(id, self) | |
| 70 | ent.lk = lk = threading.Lock() | |
| 71 | ent.st = "ld" | |
| 72 | st = None | |
| 73 | self._trim(self.keep) | |
| 74 | elif ent.st == "l": | |
| 75 | ent.relink(self) | |
| 76 | return ent.obj | |
| 77 | elif ent.st == "w": | |
| 78 | ret = ent.obj() | |
| 79 | if ret is None: | |
| 80 | del self.cur[id] | |
| 81 | ent.remove(self) | |
| 82 | ent.st = "r" | |
| 83 | continue | |
| 84 | return ret | |
| 85 | elif ent.st == "ld": | |
| 86 | lk = ent.lk | |
| 87 | st = "ld" | |
| 88 | if lk is None: | |
| 89 | continue | |
| 90 | elif ent.st == "r": | |
| 91 | continue | |
| 92 | with lk: | |
| 93 | if st is None: | |
| 94 | try: | |
| 95 | ret = ent.obj = self.load(id) | |
| 96 | ent.st = "l" | |
| 97 | return ret | |
| 98 | except: | |
| 99 | with self.lk: | |
| 100 | del self.cur[id] | |
| 101 | ent.remove(self) | |
| 102 | ent.st = "r" | |
| 103 | raise | |
| 104 | finally: | |
| 105 | ent.lk = None | |
| 106 | elif st == "ld": | |
| 107 | continue | |
| 108 | ||
| 109 | def put(self, id, ob): | |
| 110 | while True: | |
| 111 | with self.lk: | |
| 112 | ent = self.cur.get(id) | |
| 113 | if ent is None: | |
| 114 | self.cur[id] = ent = entry(id, self) | |
| 115 | ent.obj = ob | |
| 116 | ent.st = "l" | |
| 117 | self._trim(self.keep) | |
| 118 | return | |
| 119 | elif ent.st == "l": | |
| 120 | ent.obj = ob | |
| 121 | return | |
| 122 | elif ent.st == "w": | |
| 123 | ent.obj = ob | |
| 124 | return | |
| 125 | elif ent.st == "r": | |
| 126 | continue | |
| 127 | elif ent.st == "ld": | |
| 128 | lk = ent.lk | |
| 129 | if lk is None: | |
| 130 | continue | |
| 131 | with lk: | |
| 132 | continue | |
| 133 | ||
| 134 | def remove(self, id): | |
| 135 | while True: | |
| 136 | with self.lk: | |
| 137 | ent = self.cur.get(id) | |
| 138 | if ent is None: | |
| 139 | return | |
| 140 | elif ent.st == "ld": | |
| 141 | lk = ent.lk | |
| 142 | if lk is None: | |
| 143 | continue | |
| 144 | else: | |
| 145 | del self.cur[id] | |
| 146 | ent.remove(self) | |
| 147 | ent.st = "r" | |
| 148 | return | |
| 149 | with lk: | |
| 150 | continue | |
| 151 | ||
| 152 | def load(self, id): | |
| 153 | raise KeyError() |