blob: 32f5db069f5d2f1a3ee0afbf4c74f3b7aae1876e (
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
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
|
// Copyright 2017 Dolphin Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#pragma once
#include <mutex>
#include <string>
#include <utility>
#include "Common/CommonTypes.h"
#include "Common/Config/Enums.h"
#include "Common/Mutex.h"
#include "Common/TypeUtils.h"
namespace Config
{
struct Location
{
System system{};
std::string section;
std::string key;
bool operator==(const Location& other) const;
bool operator<(const Location& other) const;
};
template <typename T>
struct CachedValue
{
T value;
u64 config_version;
};
template <typename T>
class Info
{
public:
constexpr Info(Location location, T default_value)
: m_location{std::move(location)}, m_default_value{default_value},
m_cached_value{std::move(default_value), 0}
{
}
Info(const Info<T>& other)
: m_location{other.m_location}, m_default_value{other.m_default_value},
m_cached_value(other.GetCachedValue())
{
}
// Make it easy to convert Info<Enum> into Info<UnderlyingType<Enum>>
// so that enum settings can still easily work with code that doesn't care about the enum values.
template <Common::TypedEnum<T> Enum>
Info(const Info<Enum>& other)
: m_location{other.GetLocation()}, m_default_value{static_cast<T>(other.GetDefaultValue())},
m_cached_value(other.template GetCachedValueCasted<T>())
{
}
~Info() = default;
// Assignments after construction would require more locking to be thread safe.
// It seems unnecessary to have this functionality anyways.
Info& operator=(const Info&) = delete;
Info& operator=(Info&&) = delete;
// Moves are also unnecessary and would be thread unsafe without additional locking.
Info(Info&&) = delete;
constexpr const Location& GetLocation() const { return m_location; }
constexpr const T& GetDefaultValue() const { return m_default_value; }
CachedValue<T> GetCachedValue() const
{
std::lock_guard lk{m_cached_value_mutex};
return m_cached_value;
}
template <typename U>
CachedValue<U> GetCachedValueCasted() const
{
std::lock_guard lk{m_cached_value_mutex};
return {static_cast<U>(m_cached_value.value), m_cached_value.config_version};
}
// Only updates if the provided config_version is newer.
void TryToSetCachedValue(CachedValue<T> new_value) const
{
std::lock_guard lk{m_cached_value_mutex};
if (new_value.config_version > m_cached_value.config_version)
m_cached_value = std::move(new_value);
}
private:
Location m_location;
T m_default_value;
mutable CachedValue<T> m_cached_value;
// In testing, this mutex is effectively never contested.
// The lock durations are brief and each `Info` object is mostly relevant to one thread.
// Common::SpinMutex is ~3x faster than std::shared_mutex when uncontested.
mutable Common::SpinMutex m_cached_value_mutex;
};
} // namespace Config
|
