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serenity/Userland/Libraries/LibJS/Heap/GCPtr.h
Andreas Kling d5ed07fdc4 LibJS+LibWeb: Remove NonnullGCPtr<T>::operator=(GCPtr<T>) footgun
GCPtr can be null so it's not safe to assign it to a NonnullGCPtr unless
you know it to be non-null.

This exposed a number of wrong uses in LibWeb which had to be fixed as
part of this change.
2022-12-14 15:21:15 +01:00

230 lines
4.3 KiB
C++

/*
* Copyright (c) 2022, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Types.h>
namespace JS {
template<typename T>
class GCPtr;
template<typename T>
class NonnullGCPtr {
public:
NonnullGCPtr() = delete;
NonnullGCPtr(T& ptr)
: m_ptr(&ptr)
{
}
NonnullGCPtr(T const& ptr)
: m_ptr(&const_cast<T&>(ptr))
{
}
template<typename U>
NonnullGCPtr(U& ptr)
requires(IsConvertible<U*, T*>)
: m_ptr(&static_cast<T&>(ptr))
{
}
template<typename U>
NonnullGCPtr(U const& ptr)
requires(IsConvertible<U*, T*>)
: m_ptr(&const_cast<T&>(static_cast<T const&>(ptr)))
{
}
template<typename U>
NonnullGCPtr(NonnullGCPtr<U> ptr)
requires(IsConvertible<U*, T*>)
: m_ptr(ptr)
{
}
NonnullGCPtr& operator=(T const& other)
{
m_ptr = &const_cast<T&>(other);
return *this;
}
template<typename U>
NonnullGCPtr& operator=(U const& other)
requires(IsConvertible<U*, T*>)
{
m_ptr = &const_cast<T&>(static_cast<T const&>(other));
return *this;
}
template<typename U>
NonnullGCPtr& operator=(NonnullGCPtr<U> const& other)
requires(IsConvertible<U*, T*>)
{
m_ptr = const_cast<T*>(static_cast<T const*>(other.ptr()));
return *this;
}
T* operator->() const { return m_ptr; }
T& operator*() const { return *m_ptr; }
T* ptr() const { return m_ptr; }
operator T*() const { return m_ptr; }
operator T&() const { return *m_ptr; }
private:
T* m_ptr { nullptr };
};
template<typename T>
class GCPtr {
public:
GCPtr() = default;
GCPtr(T& ptr)
: m_ptr(&ptr)
{
}
GCPtr(T const& ptr)
: m_ptr(&const_cast<T&>(ptr))
{
}
GCPtr(T* ptr)
: m_ptr(ptr)
{
}
GCPtr(T const* ptr)
: m_ptr(const_cast<T*>(ptr))
{
}
GCPtr(NonnullGCPtr<T> ptr)
: m_ptr(ptr)
{
}
template<typename U>
GCPtr(NonnullGCPtr<U> ptr)
requires(IsConvertible<U*, T*>)
: m_ptr(ptr)
{
}
GCPtr(nullptr_t)
: m_ptr(nullptr)
{
}
GCPtr(GCPtr const&) = default;
GCPtr& operator=(GCPtr const&) = default;
template<typename U>
GCPtr& operator=(GCPtr<U> const& other)
requires(IsConvertible<U*, T*>)
{
m_ptr = const_cast<T*>(static_cast<T const*>(other.ptr()));
return *this;
}
GCPtr& operator=(NonnullGCPtr<T> const& other)
{
m_ptr = const_cast<T*>(other.ptr());
return *this;
}
template<typename U>
GCPtr& operator=(NonnullGCPtr<U> const& other)
requires(IsConvertible<U*, T*>)
{
m_ptr = const_cast<T*>(static_cast<T const*>(other.ptr()));
return *this;
}
GCPtr& operator=(T const& other)
{
m_ptr = &const_cast<T&>(other);
return *this;
}
template<typename U>
GCPtr& operator=(U const& other)
requires(IsConvertible<U*, T*>)
{
m_ptr = &const_cast<T&>(static_cast<T const&>(other));
return *this;
}
GCPtr& operator=(T const* other)
{
m_ptr = const_cast<T*>(other);
return *this;
}
template<typename U>
GCPtr& operator=(U const* other)
requires(IsConvertible<U*, T*>)
{
m_ptr = const_cast<T*>(static_cast<T const*>(other));
return *this;
}
T* operator->() const
{
VERIFY(m_ptr);
return m_ptr;
}
T& operator*() const
{
VERIFY(m_ptr);
return *m_ptr;
}
T* ptr() const { return m_ptr; }
operator bool() const { return !!m_ptr; }
bool operator!() const { return !m_ptr; }
operator T*() const { return m_ptr; }
private:
T* m_ptr { nullptr };
};
template<typename T, typename U>
inline bool operator==(GCPtr<T> const& a, GCPtr<U> const& b)
{
return a.ptr() == b.ptr();
}
template<typename T, typename U>
inline bool operator==(GCPtr<T> const& a, NonnullGCPtr<U> const& b)
{
return a.ptr() == b.ptr();
}
template<typename T, typename U>
inline bool operator==(NonnullGCPtr<T> const& a, NonnullGCPtr<U> const& b)
{
return a.ptr() == b.ptr();
}
template<typename T, typename U>
inline bool operator==(NonnullGCPtr<T> const& a, GCPtr<U> const& b)
{
return a.ptr() == b.ptr();
}
}