From 63865b2740ca0c7866276342d9e850cdbd43c2be Mon Sep 17 00:00:00 2001
From: Andreas Kloeckner <inform@tiker.net>
Date: Fri, 5 Jul 2013 22:01:16 -0400
Subject: [PATCH] Allow cache clearing in memoize_method
---
pytools/__init__.py | 63 +++++++++++++++++++++++++++++++++-----------
test/test_pytools.py | 24 +++++++++++++++++
2 files changed, 71 insertions(+), 16 deletions(-)
diff --git a/pytools/__init__.py b/pytools/__init__.py
index 6066a1e..af84b1b 100644
--- a/pytools/__init__.py
+++ b/pytools/__init__.py
@@ -24,6 +24,7 @@ THE SOFTWARE.
import operator
+import sys
from pytools.decorator import decorator
@@ -351,7 +352,7 @@ def single_valued(iterable, equality_pred=operator.eq):
# }}}
-# {{{ memoization
+# {{{ memoization / attribute storage
@my_decorator
def memoize(func, *args):
@@ -370,22 +371,54 @@ def memoize(func, *args):
result = func(*args)
func._memoize_dic[args] = result
return result
+
FunctionValueCache = memoize
-@my_decorator
-def memoize_method(method, instance, *args):
- cache_dict_name = intern("_memoize_dic_"+method.__name__)
- try:
- return getattr(instance, cache_dict_name)[args]
- except AttributeError:
- result = method(instance, *args)
- setattr(instance, cache_dict_name, {args: result})
- return result
- except KeyError:
- result = method(instance, *args)
- getattr(instance, cache_dict_name)[args] = result
- return result
+if sys.version_info >= (2, 5):
+ # For Python 2.5 and newer, support cache deletion by a
+ # 'method_name.clear_cache(self)' call.
+
+ def memoize_method(method):
+ cache_dict_name = intern("_memoize_dic_"+method.__name__)
+
+ def wrapper(self, *args):
+ try:
+ return getattr(self, cache_dict_name)[args]
+ except AttributeError:
+ result = method(self, *args)
+ setattr(self, cache_dict_name, {args: result})
+ return result
+ except KeyError:
+ result = method(self, *args)
+ getattr(self, cache_dict_name)[args] = result
+ return result
+
+ def clear_cache(self):
+ delattr(self, cache_dict_name)
+
+ from functools import update_wrapper
+ new_wrapper = update_wrapper(wrapper, method)
+ new_wrapper.clear_cache = clear_cache
+
+ return new_wrapper
+
+else:
+ # For sad old Python 2.4, cache deletion is not supported.
+
+ @my_decorator
+ def memoize_method(method, instance, *args):
+ cache_dict_name = intern("_memoize_dic_"+method.__name__)
+ try:
+ return getattr(instance, cache_dict_name)[args]
+ except AttributeError:
+ result = method(instance, *args)
+ setattr(instance, cache_dict_name, {args: result})
+ return result
+ except KeyError:
+ result = method(instance, *args)
+ getattr(instance, cache_dict_name)[args] = result
+ return result
def memoize_method_nested(inner):
@@ -424,8 +457,6 @@ def memoize_method_nested(inner):
return new_inner
-FunctionValueCache = memoize
-
# }}}
diff --git a/test/test_pytools.py b/test/test_pytools.py
index 7507971..f8d0109 100644
--- a/test/test_pytools.py
+++ b/test/test_pytools.py
@@ -1,5 +1,8 @@
from __future__ import division
+import pytest
+import sys # noqa
+
def test_memoize_method_nested():
from pytools import memoize_method_nested
@@ -21,3 +24,24 @@ def test_memoize_method_nested():
sc = SomeClass()
sc.f()
assert sc.run_count == 1
+
+
+@pytest.mark.skipif("sys.version_info < (2, 5)")
+def test_memoize_method_clear():
+ from pytools import memoize_method
+
+ class SomeClass:
+ def __init__(self):
+ self.run_count = 0
+
+ @memoize_method
+ def f(self):
+ self.run_count += 1
+ return 17
+
+ sc = SomeClass()
+ sc.f()
+ sc.f()
+ assert sc.run_count == 1
+
+ sc.f.clear_cache(sc)
--
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