--- a/eric7/E5Utilities/E5Cache.py Sat May 22 12:54:57 2021 +0200
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,228 +0,0 @@
-# -*- coding: utf-8 -*-
-
-# Copyright (c) 2017 - 2021 Detlev Offenbach <detlev@die-offenbachs.de>
-#
-
-"""
-Module implementing classes used for caching objects.
-"""
-
-from PyQt6.QtCore import QDateTime, QTimer
-
-
-class E5Cache:
- """
- Class implementing a LRU cache of a specific size.
-
- If the maximum number of entries is exceeded, the least recently used item
- is removed from the cache. A cache hit moves the entry to the front of the
- cache.
- """
- def __init__(self, size=100):
- """
- Constructor
-
- @param size maximum number of entries that may be stored in the cache
- @type int
- @exception ValueError raised to indicate an illegal 'size' parameter
- """
- if size < 0:
- raise ValueError("'size' parameter must be positive.")
-
- self.__size = size
-
- # internal objects
- self.__keyList = []
- 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):
- """
- Private method to move a cached item to the MRU position.
-
- @param key key of the item to be retrieved
- @type any hashable type that can be used as a dict key
- """
- self.__keyList.remove(key)
- self.__keyList.append(key)
-
- def __adjustToSize(self):
- """
- Private method to adjust the cache to its size.
- """
- if self.__size:
- removeList = self.__keyList[:-self.__size]
- self.__keyList = self.__keyList[-self.__size:]
- for key in removeList:
- del self.__store[key]
- del self.__accesStore[key]
- else:
- self.reset()
-
- def getSize(self):
- """
- Public method to get the maximum size of the cache.
-
- @return maximum number of entries of the cache
- @rtype int
- """
- return self.__size
-
- def setSize(self, newSize):
- """
- Public method to change the maximum size of the cache.
-
- @param newSize maximum number of entries that may be stored in the
- cache
- @type int
- """
- if newSize >= 0:
- 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.
-
- If the key is present in the cache, it is moved to the MRU position.
-
- @param key key of the item to be retrieved
- @type any hashable type that can be used as a dict key
- @return cached item for the given key or None, if the key is not
- present
- @rtype object or None
- """
- if key in self.__store:
- self.__hits += 1
- self.__moveLast(key)
- self.__accesStore[key] = QDateTime.currentDateTimeUtc()
- return self.__store[key]
- else:
- self.__misses += 1
- return None
-
- def add(self, key, item):
- """
- Public method to add an item to the cache.
-
- If the key is already in use, the cached item is replaced by the new
- one given and is moved to the MRU position
-
- @param key key of the item to be retrieved
- @type any hashable type that can be used as a dict key
- @param item item to be cached under the given key
- @type object
- """
- if key in self.__store:
- self.__moveLast(key)
- else:
- self.__keyList.append(key)
- self.__store[key] = item
- self.__accesStore[key] = QDateTime.currentDateTimeUtc()
-
- self.__adjustToSize()
-
- self.__maxsize = max(self.__maxsize, len(self.__keyList))
-
- def remove(self, key):
- """
- Public method to remove an item from the cache.
-
- @param key key of the item to be retrieved
- @type any hashable type that can be used as a dict key
- """
- if key in self.__store:
- del self.__store[key]
- del self.__accesStore[key]
- self.__keyList.remove(key)
-
- def clear(self):
- """
- Public method to clear the cache.
- """
- self.__keyList = []
- self.__store = {}
- self.__accesStore = {}
-
- def reset(self):
- """
- Public method to reset the cache.
-
- This is like clear() but sets the various counters to their initial
- value as well.
- """
- self.clear()
- self.__hits = 0
- self.__misses = 0
- self.__maxsize = 0
-
- def length(self):
- """
- Public method to get the current length of the cache.
-
- @return current length of the cache
- @rtype int
- """
- return len(self.__keyList)
-
- def info(self):
- """
- Public method to get some information about the cache.
-
- @return dictionary containing the cache info
- @rtype dict (with keys "hits", "misses", "maxsize", "currsize")
- """
- return {
- "hits": self.__hits,
- "misses": self.__misses,
- "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()
