ladybird/AK/NonnullRefPtr.h
Andreas Kling fe25426ee4 AK: Simplify RefPtr and NonnullRefPtr's leak_ref() functions
Use AK::exchange() to switch out the internal storage. Also mark these
functions with [[nodiscard]] to provoke an compile-time error if they
are called without using the return value.
2019-08-02 12:05:09 +02:00

246 lines
5.1 KiB
C++

#pragma once
#include <AK/Assertions.h>
#include <AK/LogStream.h>
#include <AK/Types.h>
namespace AK {
template<typename T>
class OwnPtr;
template<typename T>
class RefPtr;
template<typename T>
inline void ref_if_not_null(T* ptr)
{
if (ptr)
ptr->ref();
}
template<typename T>
inline void deref_if_not_null(T* ptr)
{
if (ptr)
ptr->deref();
}
template<typename T>
class CONSUMABLE(unconsumed) NonnullRefPtr {
public:
typedef T ElementType;
enum AdoptTag { Adopt };
RETURN_TYPESTATE(unconsumed)
NonnullRefPtr(const T& object)
: m_ptr(const_cast<T*>(&object))
{
m_ptr->ref();
}
template<typename U>
RETURN_TYPESTATE(unconsumed)
NonnullRefPtr(const U& object)
: m_ptr(&const_cast<T&>(static_cast<const T&>(object)))
{
m_ptr->ref();
}
RETURN_TYPESTATE(unconsumed)
NonnullRefPtr(AdoptTag, T& object)
: m_ptr(&object)
{
}
RETURN_TYPESTATE(unconsumed)
NonnullRefPtr(NonnullRefPtr&& other)
: m_ptr(&other.leak_ref())
{
}
template<typename U>
RETURN_TYPESTATE(unconsumed)
NonnullRefPtr(NonnullRefPtr<U>&& other)
: m_ptr(static_cast<T*>(&other.leak_ref()))
{
}
RETURN_TYPESTATE(unconsumed)
NonnullRefPtr(const NonnullRefPtr& other)
: m_ptr(const_cast<T*>(other.ptr()))
{
m_ptr->ref();
}
template<typename U>
RETURN_TYPESTATE(unconsumed)
NonnullRefPtr(const NonnullRefPtr<U>& other)
: m_ptr(const_cast<T*>(static_cast<const T*>((other.ptr()))))
{
m_ptr->ref();
}
~NonnullRefPtr()
{
deref_if_not_null(m_ptr);
m_ptr = nullptr;
#ifdef SANITIZE_PTRS
if constexpr (sizeof(T*) == 8)
m_ptr = (T*)(0xb0b0b0b0b0b0b0b0);
else
m_ptr = (T*)(0xb0b0b0b0);
#endif
}
template<typename U>
NonnullRefPtr(const OwnPtr<U>&) = delete;
template<typename U>
NonnullRefPtr& operator=(const OwnPtr<U>&) = delete;
template<typename U>
NonnullRefPtr(const RefPtr<U>&) = delete;
template<typename U>
NonnullRefPtr& operator=(const RefPtr<U>&) = delete;
NonnullRefPtr(const RefPtr<T>&) = delete;
NonnullRefPtr& operator=(const RefPtr<T>&) = delete;
NonnullRefPtr& operator=(const NonnullRefPtr& other)
{
if (m_ptr != other.m_ptr) {
deref_if_not_null(m_ptr);
m_ptr = const_cast<T*>(other.ptr());
m_ptr->ref();
}
return *this;
}
template<typename U>
NonnullRefPtr& operator=(const NonnullRefPtr<U>& other)
{
if (m_ptr != other.ptr()) {
deref_if_not_null(m_ptr);
m_ptr = const_cast<T*>(static_cast<const T*>(other.ptr()));
m_ptr->ref();
}
return *this;
}
NonnullRefPtr& operator=(NonnullRefPtr&& other)
{
if (this != &other) {
deref_if_not_null(m_ptr);
m_ptr = &other.leak_ref();
}
return *this;
}
template<typename U>
NonnullRefPtr& operator=(NonnullRefPtr<U>&& other)
{
if (this != static_cast<void*>(&other)) {
deref_if_not_null(m_ptr);
m_ptr = static_cast<T*>(&other.leak_ref());
}
return *this;
}
NonnullRefPtr& operator=(const T& object)
{
if (m_ptr != &object) {
deref_if_not_null(m_ptr);
m_ptr = const_cast<T*>(&object);
m_ptr->ref();
}
return *this;
}
[[nodiscard]] CALLABLE_WHEN(unconsumed)
SET_TYPESTATE(consumed)
T& leak_ref()
{
ASSERT(m_ptr);
return *exchange(m_ptr, nullptr);
}
CALLABLE_WHEN("unconsumed","unknown")
T* ptr()
{
ASSERT(m_ptr);
return m_ptr;
}
CALLABLE_WHEN("unconsumed","unknown")
const T* ptr() const
{
ASSERT(m_ptr);
return m_ptr;
}
CALLABLE_WHEN(unconsumed)
T* operator->()
{
ASSERT(m_ptr);
return m_ptr;
}
CALLABLE_WHEN(unconsumed)
const T* operator->() const
{
ASSERT(m_ptr);
return m_ptr;
}
CALLABLE_WHEN(unconsumed)
T& operator*()
{
ASSERT(m_ptr);
return *m_ptr;
}
CALLABLE_WHEN(unconsumed)
const T& operator*() const
{
ASSERT(m_ptr);
return *m_ptr;
}
CALLABLE_WHEN(unconsumed)
operator T*()
{
ASSERT(m_ptr);
return m_ptr;
}
CALLABLE_WHEN(unconsumed)
operator const T*() const
{
ASSERT(m_ptr);
return m_ptr;
}
CALLABLE_WHEN(unconsumed)
operator T&()
{
ASSERT(m_ptr);
return *m_ptr;
}
CALLABLE_WHEN(unconsumed)
operator const T&() const
{
ASSERT(m_ptr);
return *m_ptr;
}
private:
NonnullRefPtr() = delete;
T* m_ptr { nullptr };
};
template<typename T>
inline NonnullRefPtr<T> adopt(T& object)
{
return NonnullRefPtr<T>(NonnullRefPtr<T>::Adopt, object);
}
template<typename T>
inline const LogStream& operator<<(const LogStream& stream, const NonnullRefPtr<T>& value)
{
return stream << value.ptr();
}
}
using AK::adopt;
using AK::NonnullRefPtr;