From 0de46cca47e48bd74c4cbf0a9b025f001549426d Mon Sep 17 00:00:00 2001
From: Paul McCarthy <pauldmccarthy@gmail.com>
Date: Tue, 6 Aug 2019 22:22:35 +0100
Subject: [PATCH] ENH: Cache has an lru option
---
fsl/utils/cache.py | 24 +++++++++++++++++++++---
1 file changed, 21 insertions(+), 3 deletions(-)
diff --git a/fsl/utils/cache.py b/fsl/utils/cache.py
index 5a89817d9..e8de25aa1 100644
--- a/fsl/utils/cache.py
+++ b/fsl/utils/cache.py
@@ -42,14 +42,20 @@ class Cache(object):
raised.
"""
- def __init__(self, maxsize=100):
+ def __init__(self, maxsize=100, lru=False):
"""Create a ``Cache``.
:arg maxsize: Maximum number of items allowed in the ``Cache`` before
it starts dropping old items
+
+ :arg lru: (least recently used) If ``False`` (the default), items
+ are dropped according to their insertion time. Otherwise,
+ items are dropped according to their most recent access
+ time.
"""
self.__cache = collections.OrderedDict()
self.__maxsize = maxsize
+ self.__lru = lru
def put(self, key, value, expiry=0):
@@ -94,14 +100,26 @@ class Cache(object):
else:
entry = self.__cache[key]
+ # Check to see if the entry
+ # has expired
+ now = time.time()
+
if entry.expiry > 0:
- if time.time() - entry.storetime > entry.expiry:
+ if now - entry.storetime > entry.expiry:
self.__cache.pop(key)
if defaultSpecified: return default
else: raise Expired(key)
+ # If we are an lru cache, update
+ # this entry's expiry, and update
+ # its order in the cache dict
+ if self.__lru:
+ entry.storetime = now
+ self.__cache.pop(key)
+ self.__cache[key] = entry
+
return entry.value
@@ -134,7 +152,7 @@ class Cache(object):
- ``True`` if a default argument was specified, ``False``
otherwise.
- - The specifeid default value, or ``None`` if it wasn't
+ - The specified default value, or ``None`` if it wasn't
specified.
"""
--
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