1 files changed, 42 insertions, 0 deletions
diff --git a/cachetools/method.py b/cachetools/method.py
new file mode 100644
index 0000000..2d04f44
--- /dev/null
+++ b/cachetools/method.py
@@ -0,0 +1,42 @@
+import functools
+
+
+def _makekey_untyped(method, args, kwargs):
+    return (method, args, tuple(sorted(kwargs.items())))
+
+
+def _makekey_typed(method, args, kwargs):
+    key = _makekey_untyped(method, args, kwargs)
+    key += tuple(type(v) for v in args)
+    key += tuple(type(v) for _, v in sorted(kwargs.items()))
+    return key
+
+
+def cachedmethod(cache, typed=False):
+    """Decorator to wrap a class or instance method with a memoizing
+    callable that saves results in a (possibly shared) cache.
+
+    """
+    makekey = _makekey_typed if typed else _makekey_untyped
+
+    def decorator(method):
+        def wrapper(self, *args, **kwargs):
+            mapping = cache(self)
+            if mapping is None:
+                return method(self, *args, **kwargs)
+            key = makekey(method, args, kwargs)
+            try:
+                return mapping[key]
+            except KeyError:
+                pass
+            result = method(self, *args, **kwargs)
+            try:
+                mapping[key] = result
+            except ValueError:
+                pass  # value too large
+            return result
+
+        wrapper.cache = cache
+        return functools.update_wrapper(wrapper, method)
+
+    return decorator