1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
|
"Thread-safe in-memory cache backend."
import time
try:
from django.utils.six.moves import cPickle as pickle
except ImportError:
import pickle
from django.core.cache.backends.base import BaseCache, DEFAULT_TIMEOUT
from django.utils.synch import RWLock
# Global in-memory store of cache data. Keyed by name, to provide
# multiple named local memory caches.
_caches = {}
_expire_info = {}
_locks = {}
class LocMemCache(BaseCache):
def __init__(self, name, params):
BaseCache.__init__(self, params)
self._cache = _caches.setdefault(name, {})
self._expire_info = _expire_info.setdefault(name, {})
self._lock = _locks.setdefault(name, RWLock())
def add(self, key, value, timeout=DEFAULT_TIMEOUT, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
pickled = pickle.dumps(value, pickle.HIGHEST_PROTOCOL)
with self._lock.writer():
if self._has_expired(key):
self._set(key, pickled, timeout)
return True
return False
def get(self, key, default=None, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
pickled = None
with self._lock.reader():
if not self._has_expired(key):
pickled = self._cache[key]
if pickled is not None:
try:
return pickle.loads(pickled)
except pickle.PickleError:
return default
with self._lock.writer():
try:
del self._cache[key]
del self._expire_info[key]
except KeyError:
pass
return default
def _set(self, key, value, timeout=DEFAULT_TIMEOUT):
if len(self._cache) >= self._max_entries:
self._cull()
self._cache[key] = value
self._expire_info[key] = self.get_backend_timeout(timeout)
def set(self, key, value, timeout=DEFAULT_TIMEOUT, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
pickled = pickle.dumps(value, pickle.HIGHEST_PROTOCOL)
with self._lock.writer():
self._set(key, pickled, timeout)
def incr(self, key, delta=1, version=None):
value = self.get(key, version=version)
if value is None:
raise ValueError("Key '%s' not found" % key)
new_value = value + delta
key = self.make_key(key, version=version)
pickled = pickle.dumps(new_value, pickle.HIGHEST_PROTOCOL)
with self._lock.writer():
self._cache[key] = pickled
return new_value
def has_key(self, key, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
with self._lock.reader():
if not self._has_expired(key):
return True
with self._lock.writer():
try:
del self._cache[key]
del self._expire_info[key]
except KeyError:
pass
return False
def _has_expired(self, key):
exp = self._expire_info.get(key, -1)
if exp is None or exp > time.time():
return False
return True
def _cull(self):
if self._cull_frequency == 0:
self.clear()
else:
doomed = [k for (i, k) in enumerate(self._cache) if i % self._cull_frequency == 0]
for k in doomed:
self._delete(k)
def _delete(self, key):
try:
del self._cache[key]
except KeyError:
pass
try:
del self._expire_info[key]
except KeyError:
pass
def delete(self, key, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
with self._lock.writer():
self._delete(key)
def clear(self):
self._cache.clear()
self._expire_info.clear()
# For backwards compatibility
class CacheClass(LocMemCache):
pass
|
