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Add CAS support. #3

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Add CAS support. #3

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89 changes: 65 additions & 24 deletions mockcache.py
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Original file line number Diff line number Diff line change
Expand Up @@ -49,79 +49,89 @@
>>> mc.get("a")
'1234'
>>> mc
<mockcache.Client {'a': ('1234', None)}>
<mockcache.Client {'a': ('1234', None, 1)}>
>>> mc.add("a", "1111")
0
>>> mc.get("a")
'1234'
>>> mc
<mockcache.Client {'a': ('1234', None)}>
<mockcache.Client {'a': ('1234', None, 1)}>
>>> mc.replace("a", "2222")
1
>>> mc.get("a")
'2222'
>>> mc
<mockcache.Client {'a': ('2222', None)}>
<mockcache.Client {'a': ('2222', None, 2)}>
>>> mc.append("a", "3")
1
>>> mc.get("a")
'22223'
>>> mc
<mockcache.Client {'a': ('22223', None)}>
<mockcache.Client {'a': ('22223', None, 3)}>
>>> mc.prepend("a", "1")
1
>>> mc.get("a")
'122223'
>>> mc
<mockcache.Client {'a': ('122223', None)}>
<mockcache.Client {'a': ('122223', None, 4)}>
>>> mc.incr("a")
122224
>>> mc.get("a")
122224
>>> mc
<mockcache.Client {'a': (122224, None)}>
<mockcache.Client {'a': (122224, None, 5)}>
>>> mc.incr("a", 10)
122234
>>> mc.get("a")
122234
>>> mc
<mockcache.Client {'a': (122234, None)}>
<mockcache.Client {'a': (122234, None, 6)}>
>>> mc.decr("a")
122233
>>> mc.get("a")
122233
>>> mc
<mockcache.Client {'a': (122233, None)}>
<mockcache.Client {'a': (122233, None, 7)}>
>>> mc.decr("a", 5)
122228
>>> mc.get("a")
122228
>>> mc
<mockcache.Client {'a': (122228, None)}>
<mockcache.Client {'a': (122228, None, 8)}>
>>> mc.replace("b", "value")
0
>>> mc.get("b")
>>> mc.get("b") is None
True
>>> mc
<mockcache.Client {'a': (122228, None)}>
<mockcache.Client {'a': (122228, None, 8)}>
>>> mc.add("b", "value", 5)
1
>>> mc.get("b")
'value'
>>> mc # doctest: +ELLIPSIS
<mockcache.Client {'a': (122228, None), 'b': ('value', ...)}>
<mockcache.Client {'a': (122228, None, 8), 'b': ('value', ...)}>
>>> import time
>>> time.sleep(6)
>>> mc.get("b")
>>> mc.get("b") is None
True
>>> mc
<mockcache.Client {'a': (122228, None)}>
>>> mc.set("c", "value")
<mockcache.Client {'a': (122228, None, 8)}>
>>> mc.set("c", "foo")
1
>>> mc.gets("c")
'foo'
>>> mc.cas("c", "bar")
1
>>> mc.gets("c")
'bar'
>>> mc.set("c", "foo")
1
>>> mc.cas("c", "baz")
0
>>> mc.get_multi(["a", "b", "c"])
{'a': 122228, 'c': 'value'}
{'a': 122228, 'c': 'foo'}
>>> mc.delete("a")
1
>>> mc.get("a") is None
Expand Down Expand Up @@ -165,7 +175,7 @@ class Client(object):

"""

__slots__ = "dictionary",
__slots__ = "dictionary", "cas_ids"

# exceptions for Client
class MockcachedKeyError(Exception):
Expand All @@ -186,7 +196,10 @@ def __init__(self, *args, **kwargs):
compatibility so ignored.

"""
# map of key to (value, expiration_time, unique_id) tuple
self.dictionary = {}
# attribute name is intentionally compatible with python-memcached
self.cas_ids = {}

def set_servers(self, servers):
"""Does nothing, like `__init__`. Just for compatibility."""
Expand All @@ -202,18 +215,19 @@ def delete(self, key, time=0):
if int(time) < 1:
del self.dictionary[key]
return 1
# support for delete lock time here is surely broken
self.set(key, self.dictionary[key], time)
return 0

def incr(self, key, delta=1):
"""Increments an integer by the `key`."""
try:
value, exp = self.dictionary[key]
value, exp, id = self.dictionary[key]
except KeyError:
return
else:
value = int(value) + delta
self.dictionary[key] = value, exp
self.dictionary[key] = value, exp, id + 1
return value

def decr(self, key, delta=1):
Expand All @@ -226,8 +240,8 @@ def append(self, key, val):

"""
try:
self.dictionary[key] = str(self.dictionary[key][0]) + val, \
self.dictionary[key][1]
value, exp, id = self.dictionary[key]
self.dictionary[key] = str(value) + val, exp, id + 1
except KeyError:
return 0
else:
Expand All @@ -239,8 +253,8 @@ def prepend(self, key, val):

"""
try:
self.dictionary[key] = val + str(self.dictionary[key][0]), \
self.dictionary[key][1]
value, exp, id = self.dictionary[key]
self.dictionary[key] = val + str(value), exp, id + 1
except KeyError:
return 0
else:
Expand Down Expand Up @@ -273,14 +287,41 @@ def set(self, key, val, time=0):
time = datetime.datetime.now() + datetime.timedelta(0, time)
else:
time = datetime.datetime.fromtimestamp(time)
self.dictionary[key] = val, time
_, _, id = self.dictionary.get(key, (None, None, 0))
self.dictionary[key] = val, time, id + 1
return 1

def cas(self, key, value, time=0):
if not (key in self.dictionary and key in self.cas_ids):
return 0
_, _, id = self.dictionary[key]
if id != self.cas_ids[key]:
return 0
return self.set(key, value, time)

def reset_cas(self):
self.cas_ids.clear()

def get(self, key):
"""Retrieves a value of the `key` from the internal dictionary."""
check_key(key)
try:
val, exptime = self.dictionary[key]
val, exptime, _ = self.dictionary[key]
except KeyError:
return
else:
if exptime and exptime < datetime.datetime.now():
del self.dictionary[key]
return
return val

def gets(self, key):
"""Retrieves a value of the `key` from the internal dictionary,
recording state for future mcas calls."""
check_key(key)
try:
val, exptime, id = self.dictionary[key]
self.cas_ids[key] = id
except KeyError:
return
else:
Expand All @@ -298,7 +339,7 @@ def get_multi(self, keys):
pairs = ((key, self.dictionary[key]) for key in keys
if key in dictionary)
now = datetime.datetime.now
return dict((key, value) for key, (value, exp) in pairs
return dict((key, value) for key, (value, exp, _) in pairs
if not exp or exp > now())

def __repr__(self):
Expand Down