diff -r 4d08fb83a844 -r 21d90a3abc7c E5Utilities/E5Cache.py
--- a/E5Utilities/E5Cache.py Mon Oct 16 19:11:25 2017 +0200
+++ b/E5Utilities/E5Cache.py Mon Oct 16 19:39:57 2017 +0200
@@ -9,6 +9,8 @@
from __future__ import unicode_literals
+from PyQt5.QtCore import QDateTime, QTimer
+
# TODO: add timeout for cached entries
class E5Cache(object):
@@ -32,10 +34,16 @@
# internal objects
self.__keyList = []
- self.__store = {}
+ self.__store = {} # stores the cache entries
+ self.__accesStore = {} # stores the last access date and times
self.__hits = 0
self.__misses = 0
self.__maxsize = 0
+ self.__maxCacheTime = 0 # 0 seconds means aging is disabled
+
+ self.__cacheTimer = QTimer()
+ self.__cacheTimer.setSingleShot(True)
+ self.__cacheTimer.timeout.connect(self.__pruneCache)
def __moveLast(self, key):
"""
@@ -55,6 +63,7 @@
self.__keyList[:-self.__size], self.__keyList[-self.__size:]
for key in removeList:
del self.__store[key]
+ del self.__accesStore[key]
def getSize(self):
"""
@@ -78,6 +87,30 @@
self.__size = newSize
self.__adjustToSize()
+ def getMaximumCacheTime(self):
+ """
+ Public method to get the maximum time entries may exist in the cache.
+
+ @return maximum cache time in seconds
+ @rtype int
+ """
+ return self.__maxCacheTime
+
+ def setMaximumCacheTime(self, time):
+ """
+ Public method to set the maximum time entries may exist in the cache.
+
+ @param time maximum cache time in seconds
+ @type int
+ """
+ if time != self.__maxCacheTime:
+ self.__cacheTimer.stop()
+ self.__pruneCache()
+ self.__maxCacheTime = time
+ if self.__maxCacheTime > 0:
+ self.__cacheTimer.setInterval(self.__maxCacheTime * 1000)
+ self.__cacheTimer.start()
+
def get(self, key):
"""
Public method to get an entry from the cache given its key.
@@ -93,6 +126,7 @@
if key in self.__store:
self.__hits += 1
self.__moveLast(key)
+ self.__accesStore[key] = QDateTime.currentDateTimeUtc()
return self.__store[key]
else:
self.__misses += 1
@@ -115,6 +149,7 @@
else:
self.__keyList.append(key)
self.__store[key] = item
+ self.__accesStore[key] = QDateTime.currentDateTimeUtc()
self.__adjustToSize()
@@ -129,6 +164,7 @@
"""
if key in self.__store:
del self.__store[key]
+ del self.__accesStore[key]
self.__keyList.remove(key)
def clear(self):
@@ -137,6 +173,7 @@
"""
self.__keyList = []
self.__store = {}
+ self.__accesStore = {}
def reset(self):
"""
@@ -172,3 +209,19 @@
"maxsize": self.__maxsize,
"currsize": self.length(),
}
+
+ def __pruneCache(self):
+ """
+ Private slot to prune outdated cache entries and restart the timer.
+ """
+ if self.__maxCacheTime > 0:
+ current = QDateTime.currentDateTimeUtc()
+
+ keysToBeDeleted = []
+ for key, lastAccessTime in self.__accesStore.items():
+ if lastAccessTime.secsTo(current) > self.__maxCacheTime:
+ keysToBeDeleted.append(key)
+ for key in keysToBeDeleted:
+ self.remove(key)
+
+ self.__cacheTimer.start()
