1 // Copyright 2010 Google Inc.
2 // All rights reserved.
3 //
4 // Redistribution and use in source and binary forms, with or without
5 // modification, are permitted provided that the following conditions are
6 // met:
7 //
8 // * Redistributions of source code must retain the above copyright
9 //   notice, this list of conditions and the following disclaimer.
10 // * Redistributions in binary form must reproduce the above copyright
11 //   notice, this list of conditions and the following disclaimer in the
12 //   documentation and/or other materials provided with the distribution.
13 // * Neither the name of Google Inc. nor the names of its contributors
14 //   may be used to endorse or promote products derived from this software
15 //   without specific prior written permission.
16 //
17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 
29 /// \file utils/noncopyable.hpp
30 /// Provides the utils::noncopyable class.
31 ///
32 /// The class is provided as a separate module on its own to minimize
33 /// header-inclusion side-effects.
34 
35 #if !defined(UTILS_NONCOPYABLE_HPP)
36 #define UTILS_NONCOPYABLE_HPP
37 
38 
39 namespace utils {
40 
41 
42 /// Forbids copying a class at compile-time.
43 ///
44 /// Inheriting from this class delivers a private copy constructor and an
45 /// assignment operator that effectively forbid copying the class during
46 /// compilation.
47 ///
48 /// Always use private inheritance.
49 class noncopyable {
50     /// Data placeholder.
51     ///
52     /// The class cannot be empty; otherwise we get ABI-stability warnings
53     /// during the build, which will break it due to strict checking.
54     int _noncopyable_dummy;
55 
56     /// Private copy constructor to deny copying of subclasses.
57     noncopyable(const noncopyable&);
58 
59     /// Private assignment constructor to deny copying of subclasses.
60     noncopyable& operator=(const noncopyable&);
61 
62 protected:
63     // Explicitly needed to provide some non-private functions.  Otherwise
64     // we also get some warnings during the build.
noncopyable(void)65     noncopyable(void) {}
~noncopyable(void)66     ~noncopyable(void) {}
67 };
68 
69 
70 }  // namespace utils
71 
72 
73 #endif  // !defined(UTILS_NONCOPYABLE_HPP)
74