userdata.h Source File - ClanLib SDK
Description: userdata.h Source File

userdata.h
1/*
2** ClanLib SDK
3** Copyright (c) 1997-2020 The ClanLib Team
4**
5** This software is provided 'as-is', without any express or implied
6** warranty. In no event will the authors be held liable for any damages
7** arising from the use of this software.
8**
9** Permission is granted to anyone to use this software for any purpose,
10** including commercial applications, and to alter it and redistribute it
11** freely, subject to the following restrictions:
12**
13** 1. The origin of this software must not be misrepresented; you must not
14** claim that you wrote the original software. If you use this software
15** in a product, an acknowledgment in the product documentation would be
16** appreciated but is not required.
17** 2. Altered source versions must be plainly marked as such, and must not be
18** misrepresented as being the original software.
19** 3. This notice may not be removed or altered from any source distribution.
20**
21** Note: Some of the libraries ClanLib may link to may have additional
22** requirements or restrictions.
23**
24** File Author(s):
25**
26** Magnus Norddahl
27*/
28
29#pragma once
30
31#include <memory>
32
33namespace clan
34{
37
38 class UserDataBase
39 {
40 public:
41 virtual ~UserDataBase() { }
42 };
43
44 template<typename T>
45 class UserData : public UserDataBase
46 {
47 public:
48 UserData(const std::shared_ptr<T> &data) : data(data) { }
49 std::shared_ptr<T> data;
50 };
51
53 class UserDataOwner
54 {
55 public:
56 UserDataOwner()
57 : user_data(nullptr)
58 {
59 }
60
61 ~UserDataOwner()
62 {
63 if (user_data)
64 {
65 user_data->~UserDataBase();
66 user_data = nullptr;
67 }
68 }
69
70 template<typename T>
71 void set_data(const std::shared_ptr<T> &data)
72 {
73 if (user_data)
74 {
75 user_data->~UserDataBase();
76 user_data = nullptr;
77 }
78
79 static_assert(sizeof(UserData<T>) <= 32, "userdata_storage is too small!");
80 user_data = new(userdata_storage)UserData<T>(data);
81 }
82
83 template<typename T>
84 std::shared_ptr<T> get_data()
85 {
86 UserData<T> *d = dynamic_cast<UserData<T> *>(user_data);
87 if (d)
88 {
89 return d->data;
90 }
91 else
92 {
93 return std::shared_ptr<T>();
94 }
95 }
96
97 private:
98 UserDataOwner(const UserDataOwner &that) = delete; // do not implement
99 UserDataOwner &operator=(const UserDataOwner &that) = delete; // do not implement
100
101 UserDataBase *user_data;
102 char userdata_storage[32] = { 0 };
103 };
104
106}
clan::UserDataBase
Definition userdata.h:39
clan::UserDataBase::~UserDataBase
virtual ~UserDataBase()
Definition userdata.h:41
clan::UserDataOwner
Helper class to store any shared_ptr as user data on an object.
Definition userdata.h:54
clan::UserDataOwner::get_data
std::shared_ptr< T > get_data()
Definition userdata.h:84
clan::UserDataOwner::~UserDataOwner
~UserDataOwner()
Definition userdata.h:61
clan::UserDataOwner::set_data
void set_data(const std::shared_ptr< T > &data)
Definition userdata.h:71
clan::UserDataOwner::UserDataOwner
UserDataOwner()
Definition userdata.h:56
clan::UserData
Definition userdata.h:46
clan::UserData::UserData
UserData(const std::shared_ptr< T > &data)
Definition userdata.h:48
clan::UserData::data
std::shared_ptr< T > data
Definition userdata.h:49
clan
Definition clanapp.h:36
clan::Key::d
@ d