Add maxage

Cacheclass/cacheclass.py

@@ -1,13 +1,19 @@
 import collections
+import itertools
 import time
+
 class Cache:
-    def __init__(self, maxlen=None):
+    def __init__(self, maxage=None, maxlen=None, shrink_delay=None):
+        self.maxage = maxage
         self.maxlen = maxlen
+        self.shrink_delay = shrink_delay
+        self.last_shrink = time.time()
+
         self._dict = {}
-        #self._order = collections.deque()
         self._recency = {}
 
     def __getitem__(self, key):
+        self._shrink()
         value = self._dict[key]
         self._maintain(key)
         return value
@@ -16,23 +22,32 @@ class Cache:
         self._shrink()
         self._dict[key] = value
         self._maintain(key)
-        #print(self._dict, self._recency)
 
     def _maintain(self, key):
         self._recency[key] = time.time()
 
     def _shrink(self):
+        if self.shrink_delay is not None:
+            if time.time() - self.last_shrink > self.shrink_delay:
+                return
+
+        now = time.time()
+        self.last_shrink = now
+
         if self.maxlen is None:
-            return
-
+            pop_count = 0
+        else:
             pop_count = len(self._dict) - self.maxlen
-        if pop_count < 1:
-            return
-
         keys = sorted(self._recency.keys(), key=self._recency.get)
-        for key in keys[:pop_count]:
-            self._dict.pop(key)
-            self._recency.pop(key)
+        for key in itertools.islice(keys, 0, pop_count):
+            self.remove(key)
+
+        if self.maxage is not None:
+            for key in itertools.islice(keys, pop_count, None):
+                last_used = self._recency[key]
+                age = now - last_used
+                if age > self.maxage:
+                    self.remove(key)
 
     def get(self, key, fallback=None):
         try: