/usr/lib/python3/dist-packages/trytond/cache.py is in tryton-server 4.6.3-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 | # This file is part of Tryton. The COPYRIGHT file at the top level of
# this repository contains the full copyright notices and license terms.
from threading import Lock
from collections import OrderedDict
from sql import Table
from sql.functions import CurrentTimestamp
from trytond.config import config
from trytond.transaction import Transaction
from trytond.tools import resolve
__all__ = ['BaseCache', 'Cache', 'LRUDict']
def freeze(o):
if isinstance(o, (set, tuple, list)):
return tuple(freeze(x) for x in o)
elif isinstance(o, dict):
return frozenset((x, freeze(y)) for x, y in o.items())
else:
return o
class BaseCache(object):
_cache_instance = []
def __init__(self, name, size_limit=1024, context=True):
self._name = name
self.size_limit = size_limit
self.context = context
self._cache_instance.append(self)
def _key(self, key):
if self.context:
return (key, Transaction().user, freeze(Transaction().context))
return key
def get(self, key, default=None):
raise NotImplemented
def set(self, key, value):
raise NotImplemented
def clear(self):
raise NotImplemented
@staticmethod
def clean(dbname):
raise NotImplemented
@staticmethod
def reset(dbname, name):
raise NotImplemented
@staticmethod
def resets(dbname):
raise NotImplemented
@classmethod
def drop(cls, dbname):
raise NotImplemented
class MemoryCache(BaseCache):
"""
A key value LRU cache with size limit.
"""
_resets = {}
_resets_lock = Lock()
def __init__(self, name, size_limit=1024, context=True):
super(MemoryCache, self).__init__(name, size_limit, context)
self._cache = {}
self._timestamp = None
self._lock = Lock()
def get(self, key, default=None):
dbname = Transaction().database.name
key = self._key(key)
with self._lock:
cache = self._cache.setdefault(dbname, LRUDict(self.size_limit))
try:
result = cache[key] = cache.pop(key)
return result
except (KeyError, TypeError):
return default
def set(self, key, value):
dbname = Transaction().database.name
key = self._key(key)
with self._lock:
cache = self._cache.setdefault(dbname, LRUDict(self.size_limit))
try:
cache[key] = value
except TypeError:
pass
return value
def clear(self):
dbname = Transaction().database.name
Cache.reset(dbname, self._name)
with self._lock:
self._cache[dbname] = LRUDict(self.size_limit)
@staticmethod
def clean(dbname):
with Transaction().new_transaction(_nocache=True) as transaction,\
transaction.connection.cursor() as cursor:
table = Table('ir_cache')
cursor.execute(*table.select(table.timestamp, table.name))
timestamps = {}
for timestamp, name in cursor.fetchall():
timestamps[name] = timestamp
for inst in Cache._cache_instance:
if inst._name in timestamps:
with inst._lock:
if (not inst._timestamp
or timestamps[inst._name] > inst._timestamp):
inst._timestamp = timestamps[inst._name]
inst._cache[dbname] = LRUDict(inst.size_limit)
@staticmethod
def reset(dbname, name):
with Cache._resets_lock:
Cache._resets.setdefault(dbname, set())
Cache._resets[dbname].add(name)
@staticmethod
def resets(dbname):
table = Table('ir_cache')
with Transaction().new_transaction(_nocache=True) as transaction,\
transaction.connection.cursor() as cursor,\
Cache._resets_lock:
Cache._resets.setdefault(dbname, set())
for name in Cache._resets[dbname]:
cursor.execute(*table.select(table.name,
where=table.name == name))
if cursor.fetchone():
# It would be better to insert only
cursor.execute(*table.update([table.timestamp],
[CurrentTimestamp()],
where=table.name == name))
else:
cursor.execute(*table.insert(
[table.timestamp, table.name],
[[CurrentTimestamp(), name]]))
Cache._resets[dbname].clear()
@classmethod
def drop(cls, dbname):
for inst in cls._cache_instance:
inst._cache.pop(dbname, None)
if config.get('cache', 'class'):
Cache = resolve(config.get('cache', 'class'))
else:
Cache = MemoryCache
class LRUDict(OrderedDict):
"""
Dictionary with a size limit.
If size limit is reached, it will remove the first added items.
"""
__slots__ = ('size_limit',)
def __init__(self, size_limit, *args, **kwargs):
assert size_limit > 0
self.size_limit = size_limit
super(LRUDict, self).__init__(*args, **kwargs)
self._check_size_limit()
def __setitem__(self, key, value):
super(LRUDict, self).__setitem__(key, value)
self._check_size_limit()
def update(self, *args, **kwargs):
super(LRUDict, self).update(*args, **kwargs)
self._check_size_limit()
def setdefault(self, key, default=None):
default = super(LRUDict, self).setdefault(key, default=default)
self._check_size_limit()
return default
def _check_size_limit(self):
while len(self) > self.size_limit:
self.popitem(last=False)
class LRUDictTransaction(LRUDict):
"""
Dictionary with a size limit. (see LRUDict)
It is refreshed when transaction counter is changed.
"""
__slots__ = ('transaction', 'counter')
def __init__(self, *args, **kwargs):
super(LRUDictTransaction, self).__init__(*args, **kwargs)
self.transaction = Transaction()
self.counter = self.transaction.counter
def clear(self):
super(LRUDictTransaction, self).clear()
self.counter = self.transaction.counter
def refresh(self):
if self.counter != self.transaction.counter:
self.clear()
|