author | Todd Larsen <tlarsen@google.com> |
Wed, 01 Oct 2008 06:03:53 +0000 | |
changeset 236 | d5302883f3ac |
parent 54 | 03e267d67478 |
child 323 | ff1a9aa48cfd |
permissions | -rw-r--r-- |
54
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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1 |
"Thread-safe in-memory cache backend." |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
2 |
|
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
3 |
import time |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
4 |
try: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
5 |
import cPickle as pickle |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
6 |
except ImportError: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
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|
7 |
import pickle |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
8 |
|
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
9 |
from django.core.cache.backends.base import BaseCache |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
10 |
from django.utils.synch import RWLock |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
11 |
|
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
12 |
class CacheClass(BaseCache): |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
13 |
def __init__(self, _, params): |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
14 |
BaseCache.__init__(self, params) |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
15 |
self._cache = {} |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
16 |
self._expire_info = {} |
03e267d67478
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17 |
|
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
18 |
max_entries = params.get('max_entries', 300) |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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19 |
try: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
20 |
self._max_entries = int(max_entries) |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
21 |
except (ValueError, TypeError): |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
22 |
self._max_entries = 300 |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
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23 |
|
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
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24 |
cull_frequency = params.get('cull_frequency', 3) |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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25 |
try: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
26 |
self._cull_frequency = int(cull_frequency) |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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27 |
except (ValueError, TypeError): |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
28 |
self._cull_frequency = 3 |
03e267d67478
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29 |
|
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
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|
30 |
self._lock = RWLock() |
03e267d67478
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31 |
|
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
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32 |
def add(self, key, value, timeout=None): |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
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|
33 |
self._lock.writer_enters() |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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34 |
try: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
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|
35 |
exp = self._expire_info.get(key) |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
36 |
if exp is None or exp <= time.time(): |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
37 |
try: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
38 |
self._set(key, pickle.dumps(value), timeout) |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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39 |
except pickle.PickleError: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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40 |
pass |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
41 |
finally: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
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|
42 |
self._lock.writer_leaves() |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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43 |
|
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
44 |
def get(self, key, default=None): |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
45 |
self._lock.reader_enters() |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
46 |
try: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
47 |
exp = self._expire_info.get(key) |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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48 |
if exp is None: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
49 |
return default |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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50 |
elif exp > time.time(): |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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51 |
try: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
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|
52 |
return pickle.loads(self._cache[key]) |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
53 |
except pickle.PickleError: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
54 |
return default |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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changeset
|
55 |
finally: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
56 |
self._lock.reader_leaves() |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
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|
57 |
self._lock.writer_enters() |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
58 |
try: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
59 |
del self._cache[key] |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
60 |
del self._expire_info[key] |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
61 |
return default |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
62 |
finally: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
63 |
self._lock.writer_leaves() |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
64 |
|
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
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|
65 |
def _set(self, key, value, timeout=None): |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
66 |
if len(self._cache) >= self._max_entries: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
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|
67 |
self._cull() |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
68 |
if timeout is None: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
69 |
timeout = self.default_timeout |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
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|
70 |
self._cache[key] = value |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
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|
71 |
self._expire_info[key] = time.time() + timeout |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
72 |
|
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
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|
73 |
def set(self, key, value, timeout=None): |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
74 |
self._lock.writer_enters() |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
75 |
# Python 2.3 and 2.4 don't allow combined try-except-finally blocks. |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
76 |
try: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
77 |
try: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
78 |
self._set(key, pickle.dumps(value), timeout) |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
79 |
except pickle.PickleError: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
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|
80 |
pass |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
81 |
finally: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
82 |
self._lock.writer_leaves() |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
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|
83 |
|
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
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|
84 |
def has_key(self, key): |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
85 |
self._lock.reader_enters() |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
86 |
try: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
87 |
exp = self._expire_info.get(key) |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
88 |
if exp is None: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
89 |
return False |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
90 |
elif exp > time.time(): |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
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|
91 |
return True |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
92 |
finally: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
93 |
self._lock.reader_leaves() |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
94 |
|
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
95 |
self._lock.writer_enters() |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
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|
96 |
try: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
97 |
del self._cache[key] |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
98 |
del self._expire_info[key] |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
99 |
return False |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
100 |
finally: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
101 |
self._lock.writer_leaves() |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
102 |
|
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
103 |
def _cull(self): |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
104 |
if self._cull_frequency == 0: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
105 |
self._cache.clear() |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
106 |
self._expire_info.clear() |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
107 |
else: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
108 |
doomed = [k for (i, k) in enumerate(self._cache) if i % self._cull_frequency == 0] |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
109 |
for k in doomed: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
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|
110 |
self.delete(k) |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
111 |
|
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
112 |
def _delete(self, key): |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
113 |
try: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
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|
114 |
del self._cache[key] |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
115 |
except KeyError: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
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|
116 |
pass |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
117 |
try: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
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|
118 |
del self._expire_info[key] |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
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119 |
except KeyError: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
120 |
pass |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
121 |
|
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
122 |
def delete(self, key): |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
123 |
self._lock.writer_enters() |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
124 |
try: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
125 |
self._delete(key) |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
126 |
finally: |
03e267d67478
Major reorganization of the soc svn repo, to merge into a single App Engine
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
127 |
self._lock.writer_leaves() |