Homogenize cache implementations.

5 files changed, 17 insertions, 20 deletions

diff --git a/cachetools/lfu.py b/cachetools/lfu.py
index adb45ee..17c2b9d 100644
--- a/cachetools/lfu.py
+++ b/cachetools/lfu.py
@@ -28,7 +28,6 @@ class LFUCache(Cache):
         try:
             (key, _), = self.__counter.most_common(1)
         except ValueError:
-            msg = '%s is empty' % self.__class__.__name__
-            raise KeyError(msg) from None
+            raise KeyError('%s is empty' % type(self).__name__) from None
         else:
             return (key, self.pop(key))
diff --git a/cachetools/lru.py b/cachetools/lru.py
index 7634f9c..2508e5d 100644
--- a/cachetools/lru.py
+++ b/cachetools/lru.py
@@ -28,8 +28,7 @@ class LRUCache(Cache):
         try:
             key = next(iter(self.__order))
         except StopIteration:
-            msg = '%s is empty' % self.__class__.__name__
-            raise KeyError(msg) from None
+            raise KeyError('%s is empty' % type(self).__name__) from None
         else:
             return (key, self.pop(key))
 
diff --git a/cachetools/mru.py b/cachetools/mru.py
index 62cc9c0..92b8e76 100644
--- a/cachetools/mru.py
+++ b/cachetools/mru.py
@@ -7,29 +7,30 @@ class MRUCache(Cache):
     """Most Recently Used (MRU) cache implementation."""
 
     def __init__(self, maxsize, getsizeof=None):
-        super().__init__(maxsize, getsizeof)
+        Cache.__init__(self, maxsize, getsizeof)
         self.__order = collections.OrderedDict()
 
-    def __getitem__(self, key):
-        value = super().__getitem__(key)
+    def __getitem__(self, key, cache_getitem=Cache.__getitem__):
+        value = cache_getitem(self, key)
         self.__update(key)
         return value
 
-    def __setitem__(self, key, value):
-        super().__setitem__(key, value)
+    def __setitem__(self, key, value, cache_setitem=Cache.__setitem__):
+        cache_setitem(self, key, value)
         self.__update(key)
 
-    def __delitem__(self, key):
-        super().__delitem__(key)
+    def __delitem__(self, key, cache_delitem=Cache.__delitem__):
+        cache_delitem(self, key)
         del self.__order[key]
 
     def popitem(self):
         """Remove and return the `(key, value)` pair most recently used."""
-        if not self.__order:
-            raise KeyError(type(self).__name__ + ' cache is empty') from None
-
-        key = next(iter(self.__order))
-        return (key, self.pop(key))
+        try:
+            key = next(iter(self.__order))
+        except StopIteration:
+            raise KeyError('%s is empty' % type(self).__name__) from None
+        else:
+            return (key, self.pop(key))
 
     def __update(self, key):
         try:
diff --git a/cachetools/rr.py b/cachetools/rr.py
index 30f3822..5b47e87 100644
--- a/cachetools/rr.py
+++ b/cachetools/rr.py
@@ -29,7 +29,6 @@ class RRCache(Cache):
         try:
             key = self.__choice(list(self))
         except IndexError:
-            msg = '%s is empty' % self.__class__.__name__
-            raise KeyError(msg) from None
+            raise KeyError('%s is empty' % type(self).__name__) from None
         else:
             return (key, self.pop(key))
diff --git a/cachetools/ttl.py b/cachetools/ttl.py
index 7822e8b..528a085 100644
--- a/cachetools/ttl.py
+++ b/cachetools/ttl.py
@@ -198,8 +198,7 @@ class TTLCache(Cache):
             try:
                 key = next(iter(self.__links))
             except StopIteration:
-                msg = '%s is empty' % self.__class__.__name__
-                raise KeyError(msg) from None
+                raise KeyError('%s is empty' % type(self).__name__) from None
             else:
                 return (key, self.pop(key))