blob: 5a609340a1fd096adc5f52d4e8881ae915fcf014 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
|
#pragma once
#include <cassert>
#include <memory>
namespace cru {
template <typename T>
class SelfResolvable;
template <typename T>
class ObjectResolver {
friend SelfResolvable<T>;
private:
explicit ObjectResolver(T* o) : shared_object_ptr_(new T*(o)) {}
public:
ObjectResolver(const ObjectResolver&) = default;
ObjectResolver& operator=(const ObjectResolver&) = default;
ObjectResolver(ObjectResolver&&) = default;
ObjectResolver& operator=(ObjectResolver&&) = default;
~ObjectResolver() = default;
bool IsValid() const { return this->shared_object_ptr_ != nullptr; }
T* Resolve() const {
assert(IsValid());
return *this->shared_object_ptr_;
}
explicit operator bool() const { return this->IsValid(); }
private:
void SetResolvedObject(T* o) {
assert(IsValid());
*this->shared_object_ptr_ = o;
}
private:
std::shared_ptr<T*> shared_object_ptr_;
};
template <typename T>
class SelfResolvable {
public:
SelfResolvable() : resolver_(static_cast<T*>(this)) {}
SelfResolvable(const SelfResolvable&) = delete;
SelfResolvable& operator=(const SelfResolvable&) = delete;
// Resolvers to old object will resolve to new object.
SelfResolvable(SelfResolvable&& other)
: resolver_(std::move(other.resolver_)) {
this->resolver_.SetResolvedObject(this);
}
// Old resolvers for this object will resolve to nullptr.
// Other's resolvers will now resolve to this.
SelfResolvable& operator=(SelfResolvable&& other) {
if (this != &other) {
this->resolver_ = std::move(other.resolver_);
this->resolver_.SetResolvedObject(this);
}
return *this;
}
virtual ~SelfResolvable() {
if (this->resolver_.IsValid()) {
this->resolver_.SetResolvedObject(nullptr);
}
}
ObjectResolver<T> CreateResolver() { return resolver_; }
private:
ObjectResolver<T> resolver_;
};
} // namespace cru
|
