system/serenity
system/serenity
1
0
Fork 0
mirror of https://github.com/SerenityOS/serenity synced 2024-10-07 00:19:27 +00:00
Code Issues Packages Projects Releases Wiki Activity

AK: Allow having ref counted pointers to const object

Browse source 
We allow the ref-counting parts of an object to be mutated even when the
object itself is a const.

An important detail is that we allow invoking 'will_be_destroyed' and
'one_ref_left', which are not required to be const qualified, on const
objects.
This commit is contained in:
Itamar 2020-04-17 13:41:45 +03:00 committed by Andreas Kling
parent badbe8bc99
commit 5c1b3ce42e
1 changed files with 11 additions and 11 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

22
AK/RefCounted.h
View file

@ -32,9 +32,9 @@
namespace AK {
template<class T>
constexpr auto call_will_be_destroyed_if_present(T* object) -> decltype(object->will_be_destroyed(), TrueType {})
constexpr auto call_will_be_destroyed_if_present(const T* object) -> decltype(object->will_be_destroyed(), TrueType {})
{
object->will_be_destroyed();
const_cast<T*>(object)->will_be_destroyed();
return {};
}
@ -44,9 +44,9 @@ constexpr auto call_will_be_destroyed_if_present(...) -> FalseType
}
template<class T>
constexpr auto call_one_ref_left_if_present(T* object) -> decltype(object->one_ref_left(), TrueType {})
constexpr auto call_one_ref_left_if_present(const T* object) -> decltype(object->one_ref_left(), TrueType {})
{
object->one_ref_left();
const_cast<T*>(object)->one_ref_left();
return {};
}
@ -57,7 +57,7 @@ constexpr auto call_one_ref_left_if_present(...) -> FalseType
class RefCountedBase {
public:
void ref()
void ref() const
{
ASSERT(m_ref_count);
++m_ref_count;
@ -75,26 +75,26 @@ protected:
ASSERT(!m_ref_count);
}
void deref_base()
void deref_base() const
{
ASSERT(m_ref_count);
--m_ref_count;
}
int m_ref_count { 1 };
mutable int m_ref_count { 1 };
};
template<typename T>
class RefCounted : public RefCountedBase {
public:
void unref()
void unref() const
{
deref_base();
if (m_ref_count == 0) {
call_will_be_destroyed_if_present(static_cast<T*>(this));
delete static_cast<T*>(this);
call_will_be_destroyed_if_present(static_cast<const T*>(this));
delete static_cast<const T*>(this);
} else if (m_ref_count == 1) {
call_one_ref_left_if_present(static_cast<T*>(this));
call_one_ref_left_if_present(static_cast<const T*>(this));
}
}
};