From 5cdec57926f0c2022329908ce9a74b775ec19841 Mon Sep 17 00:00:00 2001
From: Andreas Kloeckner <inform@tiker.net>
Date: Sat, 21 Jun 2014 19:02:50 -0500
Subject: [PATCH] Add memoize_on_first_arg
---
pytools/__init__.py | 41 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/pytools/__init__.py b/pytools/__init__.py
index 6cd3205..8bf62b7 100644
--- a/pytools/__init__.py
+++ b/pytools/__init__.py
@@ -480,6 +480,47 @@ def memoize_method(method):
return new_wrapper
+def memoize_on_first_arg(function):
+ """Like :func:`memoize_method`, but for functions that take the object
+ to do memoization as first argument.
+
+ Supports cache deletion via ``function_name.clear_cache(self)``.
+
+ .. note::
+ *clear_cache* support requires Python 2.5 or newer.
+ """
+
+ cache_dict_name = intern("_memoize_dic_"
+ + function.__module__ + function.__name__)
+
+ def wrapper(obj, *args, **kwargs):
+ if kwargs:
+ key = (_HasKwargs, frozenset(kwargs.iteritems())) + args
+ else:
+ key = args
+
+ try:
+ return getattr(obj, cache_dict_name)[key]
+ except AttributeError:
+ result = function(obj, *args, **kwargs)
+ setattr(obj, cache_dict_name, {key: result})
+ return result
+ except KeyError:
+ result = function(obj, *args, **kwargs)
+ getattr(obj, cache_dict_name)[key] = result
+ return result
+
+ def clear_cache(obj):
+ delattr(obj, cache_dict_name)
+
+ if sys.version_info >= (2, 5):
+ from functools import update_wrapper
+ new_wrapper = update_wrapper(wrapper, function)
+ new_wrapper.clear_cache = clear_cache
+
+ return new_wrapper
+
+
def memoize_method_with_uncached(uncached_args=[], uncached_kwargs=set()):
"""Supports cache deletion via ``method_name.clear_cache(self)``.
--
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