ExpliticKeyTrans

Author: twhalen

py2store/utils/cache_descriptors.py

@@ -0,0 +1,141 @@
+##############################################################################
+# Copyright (c) 2003 Zope Foundation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+##############################################################################
+"""Cached properties
+See the CachedProperty class.
+
+This module was taken from https://github.com/zopefoundation/zope.cachedescriptors.
+"""
+
+from functools import update_wrapper
+
+ncaches = 0
+
+
+class _CachedProperty(object):
+    """
+    Cached property implementation class.
+    """
+
+    def __init__(self, func, *names):
+        global ncaches
+        ncaches += 1
+        self.data = (func, names,
+                     "_v_cached_property_key_%s" % ncaches,
+                     "_v_cached_property_value_%s" % ncaches)
+        update_wrapper(self, func)
+
+    def __get__(self, inst, class_):
+        if inst is None:
+            return self
+
+        func, names, key_name, value_name = self.data
+
+        key = names and [getattr(inst, name) for name in names]
+        value = getattr(inst, value_name, self)
+
+        if value is not self:
+            # We have a cached value
+            if key == getattr(inst, key_name, self):
+                # Cache is still good!
+                return value
+
+        # We need to compute and cache the value
+
+        value = func(inst)
+        setattr(inst, key_name, key)
+        setattr(inst, value_name, value)
+
+        return value
+
+
+def CachedProperty(*args):
+    """
+    CachedProperties.
+    This is usable directly as a decorator when given names, or when not. Any of these patterns
+    will work:
+    * ``@CachedProperty``
+    * ``@CachedProperty()``
+    * ``@CachedProperty('n','n2')``
+    * def thing(self: ...; thing = CachedProperty(thing)
+    * def thing(self: ...; thing = CachedProperty(thing, 'n')
+    """
+
+    if not args:  # @CachedProperty()
+        return _CachedProperty  # A callable that produces the decorated function
+
+    arg1 = args[0]
+    names = args[1:]
+    if callable(arg1):  # @CachedProperty, *or* thing = CachedProperty(thing, ...)
+        return _CachedProperty(arg1, *names)
+
+    # @CachedProperty( 'n' )
+    # Ok, must be a list of string names. Which means we are used like a factory
+    # so we return a callable object to produce the actual decorated function
+    def factory(function):
+        return _CachedProperty(function, arg1, *names)
+
+    return factory
+
+
+class Lazy(object):
+    """Lazy Attributes.
+    """
+
+    def __init__(self, func, name=None):
+        if name is None:
+            name = func.__name__
+        self.data = (func, name)
+        update_wrapper(self, func)
+
+    def __get__(self, inst, class_):
+        if inst is None:
+            return self
+
+        func, name = self.data
+        value = func(inst)
+        inst.__dict__[name] = value
+        return value
+
+
+class readproperty(object):
+
+    def __init__(self, func):
+        self.func = func
+        update_wrapper(self, func)
+
+    def __get__(self, inst, class_):
+        if inst is None:
+            return self
+
+        func = self.func
+        return func(inst)
+
+
+class cachedIn(object):
+    """Cached property with given cache attribute."""
+
+    def __init__(self, attribute_name):
+        self.attribute_name = attribute_name
+
+    def __call__(self, func):
+
+        def get(instance):
+            try:
+                value = getattr(instance, self.attribute_name)
+            except AttributeError:
+                value = func(instance)
+                setattr(instance, self.attribute_name, value)
+            return value
+
+        update_wrapper(get, func)
+
+        return property(get)

setup.py

@@ -8,7 +8,7 @@ def readme():
 
 setup(
     name='py2store',
-    version='0.0.5',
+    version='0.0.6',
     description='DAO for Python: Tools to create simple and consistent interfaces to complicated and varied data sources.',
     long_description=readme(),
     long_description_content_type="text/markdown",
@@ -19,7 +19,7 @@ def readme():
     install_requires=[],
     include_package_data=True,
     zip_safe=False,
-    download_url='https://github.com/i2mint/py2store/archive/v0.0.5.zip',
+    download_url='https://github.com/i2mint/py2store/archive/v0.0.6.zip',
     keywords=['storage', 'interface'],
     classifiers=[
         'Development Status :: 3 - Alpha',
@@ -31,7 +31,6 @@ def readme():
         'Intended Audience :: Developers',
         'Topic :: Software Development',
         'License :: OSI Approved :: Apache Software License',
-        'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
     ],
 )