libretro-dolphin/Source/Core/Common/ScopeGuard.h
Léo Lam 44b4c2db49 Common: Avoid std::function overhead in ScopeGuard
So far in all our uses of ScopeGuard, the type of the callable is
usually just a lambda or a function pointer, so there is no need
to rely on std::function's type erasure.

While the cost of using std::function is probably negligible, it still
causes some unnecessary overhead that can be avoided by making
ScopeGuard a templated class. Thanks to class template argument
deduction in C++17 most existing usages do not even need to be changed.

See https://godbolt.org/z/KcoPni for a comparison between
a ScopeGuard that uses std::function and one that doesn't
2020-02-15 21:33:31 +01:00

44 lines
801 B
C++

// Copyright 2015 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.
#pragma once
#include <functional>
namespace Common
{
class ScopeGuard final
{
public:
template <class Callable>
ScopeGuard(Callable&& finalizer) : m_finalizer(std::forward<Callable>(finalizer))
{
}
ScopeGuard(ScopeGuard&& other) : m_finalizer(std::move(other.m_finalizer))
{
other.m_finalizer = nullptr;
}
~ScopeGuard() { Exit(); }
void Dismiss() { m_finalizer = nullptr; }
void Exit()
{
if (m_finalizer)
{
m_finalizer(); // must not throw
m_finalizer = nullptr;
}
}
ScopeGuard(const ScopeGuard&) = delete;
void operator=(const ScopeGuard&) = delete;
private:
std::function<void()> m_finalizer;
};
} // Namespace Common