diff options
Diffstat (limited to 'taskflow/utils/misc.py')
| -rw-r--r-- | taskflow/utils/misc.py | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/taskflow/utils/misc.py b/taskflow/utils/misc.py index f3cb44f..74c2752 100644 --- a/taskflow/utils/misc.py +++ b/taskflow/utils/misc.py @@ -27,6 +27,7 @@ import os import re import string import sys +import threading import time import traceback @@ -163,7 +164,7 @@ def decode_json(raw_data, root_types=(dict,)): class cachedproperty(object): - """A descriptor property that is only evaluated once.. + """A *thread-safe* descriptor property that is only evaluated once. This caching descriptor can be placed on instance methods to translate those methods into properties that will be cached in the instance (avoiding @@ -176,6 +177,7 @@ class cachedproperty(object): after the first call to 'get_thing' occurs. """ def __init__(self, fget): + self._lock = threading.RLock() # If a name is provided (as an argument) then this will be the string # to place the cached attribute under if not then it will be the # function itself to be wrapped into a property. @@ -205,12 +207,19 @@ class cachedproperty(object): def __get__(self, instance, owner): if instance is None: return self - try: + # Quick check to see if this already has been made (before acquiring + # the lock). This is safe to do since we don't allow deletion after + # being created. + if hasattr(instance, self._attr_name): return getattr(instance, self._attr_name) - except AttributeError: - value = self._fget(instance) - setattr(instance, self._attr_name, value) - return value + else: + with self._lock: + try: + return getattr(instance, self._attr_name) + except AttributeError: + value = self._fget(instance) + setattr(instance, self._attr_name, value) + return value def wallclock(): |