1# Copyright 2016 Free Software Foundation, Inc.
2# This file is part of GNU Radio
3#
4# GNU Radio Companion is free software; you can redistribute it and/or
5# modify it under the terms of the GNU General Public License
6# as published by the Free Software Foundation; either version 2
7# of the License, or (at your option) any later version.
8#
9# GNU Radio Companion is distributed in the hope that it will be useful,
10# but WITHOUT ANY WARRANTY; without even the implied warranty of
11# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12# GNU General Public License for more details.
13#
14# You should have received a copy of the GNU General Public License
15# along with this program; if not, write to the Free Software
16# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
17
18import functools
19
20
21class lazy_property(object):
22
23    def __init__(self, func):
24        self.func = func
25        functools.update_wrapper(self, func)
26
27    def __get__(self, instance, owner):
28        if instance is None:
29            return self
30        value = self.func(instance)
31        setattr(instance, self.func.__name__, value)
32        return value
33
34
35def nop_write(prop):
36    """Make this a property with a nop setter"""
37    def nop(self, value):
38        pass
39    return prop.setter(nop)
40