Coverage for python/lsst/daf/persistence/readProxy.py: 68%
61 statements
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« prev ^ index » next coverage.py v6.4, created at 2022-06-02 03:43 -0700
1#!/usr/bin/env python
3#
4# LSST Data Management System
5# Copyright 2008, 2009, 2010 LSST Corporation.
6#
7# This product includes software developed by the
8# LSST Project (http://www.lsst.org/).
9#
10# This program is free software: you can redistribute it and/or modify
11# it under the terms of the GNU General Public License as published by
12# the Free Software Foundation, either version 3 of the License, or
13# (at your option) any later version.
14#
15# This program is distributed in the hope that it will be useful,
16# but WITHOUT ANY WARRANTY; without even the implied warranty of
17# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18# GNU General Public License for more details.
19#
20# You should have received a copy of the LSST License Statement and
21# the GNU General Public License along with this program. If not,
22# see <http://www.lsstcorp.org/LegalNotices/>.
23#
25# -*- python -*-
27"""This module defines the ReadProxy class."""
29from .persistence import ReadProxyBase
32class ReadProxy(ReadProxyBase):
33 """ReadProxy provides a lazy-loading object that is initialized by a
34 callback function set in ReadProxy's constructor. Adapted from
35 peak.util.proxies.LazyProxy, which was written by Phillip J. Eby
36 (peak@eby-sarna.com)."""
38 __slots__ = ('__cache__', '__callback__')
40 def __init__(self, func):
41 ReadProxyBase.__init__(self)
42 set_callback(self, func)
44 def __getattr__(self, attr):
45 getattr(self.__subject__, attr)
47 def __setattr__(self, attr, val):
48 setattr(self.__subject__, attr, val)
50 def __delattr__(self, attr):
51 delattr(self.__subject__, attr)
53 def __bool__(self):
54 return bool(self.__subject__)
56 def __getitem__(self, arg):
57 return self.__subject__[arg]
59 def __setitem__(self, arg, val):
60 self.__subject__[arg] = val
62 def __delitem__(self, arg):
63 del self.__subject__[arg]
65 def __getslice__(self, i, j):
66 return self.__subject__[i:j]
68 def __setslice__(self, i, j, val):
69 self.__subject__[i:j] = val
71 def __delslice__(self, i, j):
72 del self.__subject__[i:j]
74 def __contains__(self, ob):
75 return ob in self.__subject__
77 for name in 'repr str hash len abs complex int long float iter oct hex'.split():
78 exec("def __%s__(self): return %s(self.__subject__)" % (name, name))
80 for name in 'cmp', 'coerce', 'divmod':
81 exec("def __%s__(self, ob): return %s(self.__subject__, ob)" % (name,
82 name))
84 for name, op in [
85 ('lt', '<'), ('gt', '>'), ('le', '<='), ('ge', '>='),
86 ('eq', '=='), ('ne', '!=')
87 ]:
88 exec("def __%s__(self, ob): return self.__subject__ %s ob" % (name, op))
90 for name, op in [('neg', '-'), ('pos', '+'), ('invert', '~')]:
91 exec("def __%s__(self): return %s self.__subject__" % (name, op))
93 for name, op in [
94 ('or', '|'), ('and', '&'), ('xor', '^'),
95 ('lshift', '<<'), ('rshift', '>>'),
96 ('add', '+'), ('sub', '-'), ('mul', '*'), ('div', '/'),
97 ('mod', '%'), ('truediv', '/'), ('floordiv', '//')
98 ]:
99 exec((
100 "def __%(name)s__(self,ob):\n"
101 " return self.__subject__ %(op)s ob\n"
102 "\n"
103 "def __r%(name)s__(self,ob):\n"
104 " return ob %(op)s self.__subject__\n"
105 "\n"
106 "def __i%(name)s__(self,ob):\n"
107 " self.__subject__ %(op)s=ob\n"
108 " return self\n"
109 ) % locals())
111 del name, op
113 # Oddball signatures
115 def __rdivmod__(self, ob):
116 return divmod(ob, self.__subject__)
118 def __pow__(self, *args):
119 return pow(self.__subject__, *args)
121 def __ipow__(self, ob):
122 self.__subject__ **= ob
123 return self
125 def __rpow__(self, ob):
126 return pow(ob, self.__subject__)
129get_callback = ReadProxy.__callback__.__get__
130set_callback = ReadProxy.__callback__.__set__
131get_cache = ReadProxy.__cache__.__get__
132set_cache = ReadProxy.__cache__.__set__
135def _subject(self, get_cache=get_cache, set_cache=set_cache):
136 try:
137 return get_cache(self)
138 except AttributeError:
139 set_cache(self, get_callback(self)())
140 return get_cache(self)
143ReadProxy.__subject__ = property(_subject, set_cache)
144del _subject