ladybird/AK/Retainable.h
Andreas Kling dd5ca1940a AK: Hoist the assertion in Retainable::release() to RetainableBase.
This means we don't have to generate a __PRETTY_FUNCTION__ symbol there
for each and every specialization.
2019-03-16 13:48:56 +01:00

80 lines
1.4 KiB
C++

#pragma once
#include "Assertions.h"
#include "StdLibExtras.h"
namespace AK {
template<class T>
constexpr auto call_will_be_destroyed_if_present(T* object) -> decltype(object->will_be_destroyed(), TrueType { })
{
object->will_be_destroyed();
return { };
}
constexpr auto call_will_be_destroyed_if_present(...) -> FalseType
{
return { };
}
template<class T>
constexpr auto call_one_retain_left_if_present(T* object) -> decltype(object->one_retain_left(), TrueType { })
{
object->one_retain_left();
return { };
}
constexpr auto call_one_retain_left_if_present(...) -> FalseType
{
return { };
}
class RetainableBase {
public:
void retain()
{
ASSERT(m_retain_count);
++m_retain_count;
}
int retain_count() const
{
return m_retain_count;
}
protected:
RetainableBase() { }
~RetainableBase()
{
ASSERT(!m_retain_count);
}
void release_base()
{
ASSERT(m_retain_count);
--m_retain_count;
}
int m_retain_count { 1 };
};
template<typename T>
class Retainable : public RetainableBase {
public:
void release()
{
release_base();
if (m_retain_count == 0) {
call_will_be_destroyed_if_present(static_cast<T*>(this));
delete static_cast<T*>(this);
} else if (m_retain_count == 1) {
call_one_retain_left_if_present(static_cast<T*>(this));
}
}
};
}
using AK::Retainable;