Add new shared pointer and make use of it

arm9/source/core/AtomicSharedPtr.cpp

@@ -0,0 +1,35 @@
+#include "common.h"
+#include <libtwl/rtos/rtosIrq.h>
+#include "AtomicSharedPtr.h"
+
+void AtomicSharedPtrBase::Reset(void* newObject, RefCount* newRefCount, bool increaseNewRefCount)
+{
+    u32 irq = rtos_disableIrqs(); // 1
+    auto refCount = _refCount;
+    _object = newObject;
+    _refCount = newRefCount;
+    if (increaseNewRefCount && _refCount)
+    {
+        _refCount->refCount++;
+    }
+    if (refCount && --refCount->refCount == 0) [[gnu::unlikely]]
+    {
+        refCount->weakRefCount++; // ensure the ref count is not destructed elsewhere
+        rtos_restoreIrqs(irq); // 1
+        refCount->DestructObject();
+        irq = rtos_disableIrqs(); // 2
+        if (--refCount->weakRefCount == 0) [[gnu::unlikely]]
+        {
+            rtos_restoreIrqs(irq); // 2
+            delete refCount;
+        }
+        else
+        {
+            rtos_restoreIrqs(irq); // 2
+        }
+    }
+    else
+    {
+        rtos_restoreIrqs(irq); // 1
+    }
+}

arm9/source/core/AtomicSharedPtr.h

@@ -0,0 +1,134 @@
+#pragma once
+#include <type_traits>
+#include <libtwl/rtos/rtosIrq.h>
+#include "SharedPtr.h"
+
+class AtomicSharedPtrBase
+{
+public:
+    void Reset()
+    {
+        Reset(nullptr, nullptr, false);
+    }
+
+protected:
+    void* volatile _object;
+    RefCount* volatile _refCount;
+
+    AtomicSharedPtrBase()
+        : _object(nullptr), _refCount(nullptr) { }
+
+    AtomicSharedPtrBase(void* object, RefCount* refCount)
+        : _object(object), _refCount(refCount) { }
+
+    ~AtomicSharedPtrBase()
+    {
+        Reset(nullptr, nullptr, false);
+    }
+
+    void Reset(void* newObject, RefCount* newRefCount, bool increaseNewRefCount);
+};
+
+template <class T>
+class AtomicSharedPtr : public AtomicSharedPtrBase
+{
+public:
+    AtomicSharedPtr() { }
+
+    AtomicSharedPtr(std::nullptr_t) { }
+
+    AtomicSharedPtr(const SharedPtr<T>& sharedPtr)
+        : AtomicSharedPtrBase(sharedPtr._object, sharedPtr._refCount)
+    {
+        if (_refCount)
+        {
+            shared_ptr_increase_ref_count(_refCount->refCount);
+        }
+    }
+
+    template <class Y> requires std::assignable_from<T*&, Y*>
+    AtomicSharedPtr(const SharedPtr<Y>& sharedPtr)
+        : AtomicSharedPtrBase(static_cast<T*>(sharedPtr.GetPointer()), sharedPtr._refCount)
+    {
+        if (_refCount)
+        {
+            shared_ptr_increase_ref_count(_refCount->refCount);
+        }
+    }
+
+    template <class Y>
+    explicit AtomicSharedPtr(const SharedPtr<Y>& sharedPtr)
+        : AtomicSharedPtrBase(static_cast<T*>(sharedPtr.GetPointer()), sharedPtr._refCount)
+    {
+        if (_refCount)
+        {
+            shared_ptr_increase_ref_count(_refCount->refCount);
+        }
+    }
+
+    AtomicSharedPtr(SharedPtr<T>&& sharedPtr)
+        : AtomicSharedPtrBase(sharedPtr._object, sharedPtr._refCount)
+    {
+        sharedPtr._object = nullptr;
+        sharedPtr._refCount = nullptr;
+    }
+
+    template <class Y> requires std::assignable_from<T*&, Y*>
+    AtomicSharedPtr(SharedPtr<Y>&& sharedPtr)
+        : AtomicSharedPtrBase(static_cast<T*>(sharedPtr.GetPointer()), sharedPtr._refCount)
+    {
+        sharedPtr._object = nullptr;
+        sharedPtr._refCount = nullptr;
+    }
+
+    template <class Y>
+    explicit AtomicSharedPtr(SharedPtr<Y>&& sharedPtr)
+        : AtomicSharedPtrBase(static_cast<T*>(sharedPtr.GetPointer()), sharedPtr._refCount)
+    {
+        sharedPtr._object = nullptr;
+        sharedPtr._refCount = nullptr;
+    }
+
+    AtomicSharedPtr& operator=(const SharedPtr<T>& sharedPtr)
+    {
+        Reset(sharedPtr._object, sharedPtr._refCount, true);
+        return *this;
+    }
+
+    template <class Y> requires std::assignable_from<T*&, Y*>
+    AtomicSharedPtr<T>& operator=(const SharedPtr<Y>& sharedPtr)
+    {
+        Reset(static_cast<T*>(sharedPtr.GetPointer()), sharedPtr._refCount, true);
+        return *this;
+    }
+
+    AtomicSharedPtr& operator=(SharedPtr<T>&& sharedPtr)
+    {
+        Reset(sharedPtr._object, sharedPtr._refCount, false);
+        sharedPtr._object = nullptr;
+        sharedPtr._refCount = nullptr;
+        return *this;
+    }
+
+    template <class Y> requires std::assignable_from<T*&, Y*>
+    AtomicSharedPtr<T>& operator=(SharedPtr<Y>&& sharedPtr)
+    {
+        Reset(static_cast<T*>(sharedPtr.GetPointer()), sharedPtr._refCount, false);
+        sharedPtr._object = nullptr;
+        sharedPtr._refCount = nullptr;
+        return *this;
+    }
+
+    SharedPtr<T> Lock() const
+    {
+        u32 irq = rtos_disableIrqs();
+        auto object = static_cast<T*>(_object);
+        auto refCount = _refCount;
+        if (refCount)
+        {
+            refCount->refCount++;
+        }
+        rtos_restoreIrqs(irq);
+        return SharedPtr<T>(object, refCount);
+    }
+};

arm9/source/core/EnableSharedFromThis.h

@@ -0,0 +1,42 @@
+#pragma once
+#include "SharedPtr.h"
+#include "WeakPtr.h"
+
+class EnableSharedFromThisBase
+{
+    template <class Y>
+    friend class SharedPtr;
+
+    template <class Y>
+    friend class EnableSharedFromThis;
+
+private:
+    EnableSharedFromThisBase() = default;
+};
+
+template <class T>
+class EnableSharedFromThis : public EnableSharedFromThisBase
+{
+    template <class Y>
+    friend class SharedPtr;
+
+protected:
+    SharedPtr<T> SharedFromThis()
+    {
+        return __sharedFromThisWeakPtr.Lock();
+    }
+
+    WeakPtr<T> WeakFromThis()
+    {
+        return __sharedFromThisWeakPtr;
+    }
+
+private:
+    WeakPtr<T> __sharedFromThisWeakPtr;
+
+    template <class Y>
+    void __SetSharedFromThisWeakPtr(const SharedPtr<Y>& sharedPtr)
+    {
+        __sharedFromThisWeakPtr = WeakPtr<Y>(sharedPtr.GetPointer(), sharedPtr._refCount);
+    }
+};

arm9/source/core/RefCount.h

@@ -0,0 +1,58 @@
+#pragma once
+#include <array>
+
+extern "C" void shared_ptr_increase_ref_count(vu32& refCount);
+
+class RefCount
+{
+public:
+    vu32 refCount;
+    vu32 weakRefCount;
+
+    virtual ~RefCount() = default;
+
+    virtual void DestructObject() = 0;
+
+protected:
+    explicit RefCount()
+        : refCount(1), weakRefCount(0) { }
+};
+
+template <class T>
+class StandaloneRefCount : public RefCount
+{
+public:
+    explicit StandaloneRefCount(T* object)
+        : _object(object) { }
+
+    void DestructObject() final
+    {
+        delete _object;
+    }
+
+private:
+    T* _object;
+};
+
+template <class T>
+class alignas(T) MakeSharedRefCount : public RefCount
+{
+public:
+    explicit MakeSharedRefCount(auto&&... args)
+    {
+        new (_object.data()) T(std::forward<decltype(args)>(args)...);
+    }
+
+    T* GetObject()
+    {
+        return reinterpret_cast<T*>(_object.data());
+    }
+
+    void DestructObject() final
+    {
+        reinterpret_cast<T*>(_object.data())->~T();
+    }
+
+private:
+    std::array<u8, sizeof(T)> _object alignas(T);
+};

arm9/source/core/SharedPtr.cpp

@@ -0,0 +1,31 @@
+#include "common.h"
+#include <libtwl/rtos/rtosIrq.h>
+#include "SharedPtr.h"
+
+void SharedPtrBase::ResetIntern()
+{
+    auto refCount = _refCount;
+    _object = nullptr;
+    _refCount = nullptr;
+    u32 irq = rtos_disableIrqs(); // 1
+    if (--refCount->refCount == 0) [[gnu::unlikely]]
+    {
+        refCount->weakRefCount++; // ensure the ref count is not destructed elsewhere
+        rtos_restoreIrqs(irq); // 1
+        refCount->DestructObject();
+        irq = rtos_disableIrqs(); // 2
+        if (--refCount->weakRefCount == 0) [[gnu::unlikely]]
+        {
+            rtos_restoreIrqs(irq); // 2
+            delete refCount;
+        }
+        else
+        {
+            rtos_restoreIrqs(irq); // 2
+        }
+    }
+    else
+    {
+        rtos_restoreIrqs(irq); // 1
+    }
+}

arm9/source/core/SharedPtr.h

@@ -1,163 +1,209 @@
 #pragma once
+#include <type_traits>
+#include "RefCount.h"
 
-static inline u32 arm_getCpsr()
-{
-    u32 cpsr;
-    asm volatile("mrs %0, cpsr" : "=r" (cpsr));
-    return cpsr;
-}
-
-static inline void arm_setCpsrControl(u32 cpsrControl)
-{
-    asm volatile("msr cpsr_c, %0" :: "r" (cpsrControl) : "cc");
-}
-
-static inline u32 arm_disableIrqs(void)
-{
-    u32 oldCpsr = arm_getCpsr();
-    arm_setCpsrControl(oldCpsr | 0x80);
-    return oldCpsr;
-}
-
-static inline void arm_restoreIrqs(u32 oldCpsr)
-{
-    arm_setCpsrControl(oldCpsr);
-}
+class EnableSharedFromThisBase;
 
 template <class T>
-class SharedPtr
+class EnableSharedFromThis;
+
+class SharedPtrBase
 {
-    T* _pointer;
-    vu32* _refCount;
-
 public:
-    SharedPtr()
-        : _pointer(nullptr), _refCount(nullptr) { (void)sizeof(T); }
-
-    explicit SharedPtr(T* pointer)
-        : _pointer(pointer), _refCount(pointer ? new u32(1) : nullptr) { (void)sizeof(T); }
-
-    SharedPtr(const SharedPtr& other)
+    void Reset()
     {
-        u32 irq = arm_disableIrqs();
-        _pointer = other._pointer;
-        _refCount = other._refCount;
-        if (_pointer)
+        if (_refCount != nullptr)
         {
-            (*_refCount)++;
+            ResetIntern();
         }
-        arm_restoreIrqs(irq);
     }
 
-    SharedPtr(SharedPtr&& other)
-        : _pointer(other._pointer), _refCount(other._refCount)
-    {
-        other._pointer = nullptr;
-        other._refCount = nullptr;
-    }
+protected:
+    void* _object;
+    RefCount* _refCount;
 
-    ~SharedPtr()
+    SharedPtrBase()
+        : _object(nullptr), _refCount(nullptr) { }
+
+    SharedPtrBase(void* object, RefCount* refCount)
+        : _object(object), _refCount(refCount) { }
+
+    SharedPtrBase(const void* object, RefCount* refCount)
+        : _object((void*)object), _refCount(refCount) { }
+
+    ~SharedPtrBase()
     {
         Reset();
     }
 
-    [[gnu::noinline]]
+    void ResetIntern();
+};
+
+template <class T>
+class SharedPtr : public SharedPtrBase
+{
+    template <class Y> friend class WeakPtr;
+    template <class Y> friend class SharedPtr;
+    template <class Y> friend class AtomicSharedPtr;
+    template <class Y> friend class EnableSharedFromThis;
+
+public:
+    SharedPtr() { }
+
+    SharedPtr(std::nullptr_t) { }
+
+    explicit SharedPtr(T* object)
+        : SharedPtrBase(object, object == nullptr ? nullptr : new StandaloneRefCount<T>(object))
+    {
+        if (_object != nullptr)
+        {
+            if constexpr (std::is_convertible<T*, EnableSharedFromThisBase*>::value)
+            {
+                _refCount->weakRefCount = 1;
+                GetPointer()->__SetSharedFromThisWeakPtr(*this);
+            }
+        }
+    }
+
+    template <class Y> requires std::assignable_from<T*&, Y*>
+    explicit SharedPtr(Y* object)
+        : SharedPtrBase(static_cast<T*>(object), object == nullptr ? nullptr : new StandaloneRefCount<Y>(object))
+    {
+        if (object != nullptr)
+        {
+            if constexpr (std::is_convertible<Y*, EnableSharedFromThisBase*>::value)
+            {
+                _refCount->weakRefCount = 1;
+                GetPointer()->__SetSharedFromThisWeakPtr(*this);
+            }
+        }
+    }
+
+    SharedPtr(const SharedPtr& other)
+        : SharedPtrBase(other._object, other._refCount)
+    {
+        if (_refCount)
+        {
+            shared_ptr_increase_ref_count(_refCount->refCount);
+        }
+    }
+
+    template <class Y> requires std::assignable_from<T*&, Y*>
+    SharedPtr(const SharedPtr<Y>& other)
+        : SharedPtrBase(static_cast<T*>(other.GetPointer()), other._refCount)
+    {
+        if (_refCount)
+        {
+            shared_ptr_increase_ref_count(_refCount->refCount);
+        }
+    }
+
+    template <class Y>
+    explicit SharedPtr(const SharedPtr<Y>& other)
+        : SharedPtrBase(static_cast<T*>(other.GetPointer()), other._refCount)
+    {
+        if (_refCount)
+        {
+            shared_ptr_increase_ref_count(_refCount->refCount);
+        }
+    }
+
+    SharedPtr(SharedPtr&& other)
+        : SharedPtrBase(other._object, other._refCount)
+    {
+        other._object = nullptr;
+        other._refCount = nullptr;
+    }
+
+    template <class Y> requires std::assignable_from<T*&, Y*>
+    SharedPtr(SharedPtr<Y>&& other)
+        : SharedPtrBase(static_cast<T*>(other.GetPointer()), other._refCount)
+    {
+        other._object = nullptr;
+        other._refCount = nullptr;
+    }
+
+    template <class Y>
+    explicit SharedPtr(SharedPtr<Y>&& other)
+        : SharedPtrBase(static_cast<T*>(other.GetPointer()), other._refCount)
+    {
+        other._object = nullptr;
+        other._refCount = nullptr;
+    }
+
+    static SharedPtr<T> MakeShared(auto&&... args)
+    {
+        auto refCount = new MakeSharedRefCount<T>(std::forward<decltype(args)>(args)...);
+        return SharedPtr<T>(refCount->GetObject(), refCount, true);
+    }
+
     SharedPtr& operator=(const SharedPtr& other)
     {
-        u32 irq = arm_disableIrqs();
-        T* pointer = _pointer;
-        if (pointer)
+        Reset();
+        _object = other._object;
+        _refCount = other._refCount;
+        if (_refCount)
         {
-            vu32* refCount = _refCount;
-            u32 newValue = *refCount - 1;
-            *refCount = newValue;
-            _pointer = other._pointer;
-            _refCount = other._refCount;
-            if (_pointer)
-            {
-                (*_refCount)++;
-            }
-            arm_restoreIrqs(irq);
-            if (newValue == 0)
-            {
-                delete pointer;
-                delete refCount;
-            }
-        }
-        else
-        {
-            _pointer = other._pointer;
-            _refCount = other._refCount;
-            if (_pointer)
-            {
-                (*_refCount)++;
-            }
-            arm_restoreIrqs(irq);
+            shared_ptr_increase_ref_count(_refCount->refCount);
+        }
+        return *this;
+    }
+
+    template <class Y> requires std::assignable_from<T*&, Y*>
+    SharedPtr<T>& operator=(const SharedPtr<Y>& other)
+    {
+        Reset();
+        _object = static_cast<T*>(other.GetPointer());
+        _refCount = other._refCount;
+        if (_refCount)
+        {
+            shared_ptr_increase_ref_count(_refCount->refCount);
         }
         return *this;
     }
 
-    [[gnu::noinline]]
     SharedPtr& operator=(SharedPtr&& other)
     {
-        u32 irq = arm_disableIrqs();
-        T* pointer = _pointer;
-        if (pointer)
-        {
-            vu32* refCount = _refCount;
-            u32 newValue = *refCount - 1;
-            *refCount = newValue;
-            _pointer = other._pointer;
-            _refCount = other._refCount;
-            other._pointer = nullptr;
-            other._refCount = nullptr;
-            arm_restoreIrqs(irq);
-            if (newValue == 0)
-            {
-                delete pointer;
-                delete refCount;
-            }
-        }
-        else
-        {
-            _pointer = other._pointer;
-            _refCount = other._refCount;
-            other._pointer = nullptr;
-            other._refCount = nullptr;
-            arm_restoreIrqs(irq);
-        }
+        Reset();
+        _object = other._object;
+        _refCount = other._refCount;
+        other._object = nullptr;
+        other._refCount = nullptr;
         return *this;
     }
 
-    [[gnu::noinline]]
-    void Reset()
+    template <class Y> requires std::assignable_from<T*&, Y*>
+    SharedPtr<T>& operator=(SharedPtr<Y>&& other)
     {
-        u32 irq = arm_disableIrqs();
-        T* pointer = _pointer;
-        if (pointer)
-        {
-            vu32* refCount = _refCount;
-            u32 newValue = *refCount - 1;
-            *refCount = newValue;
-            _pointer = nullptr;
-            _refCount = nullptr;
-            arm_restoreIrqs(irq);
-            if (newValue == 0)
-            {
-                delete pointer;
-                delete refCount;
-            }
-        }
-        else
-        {
-            arm_restoreIrqs(irq);
-        }
+        Reset();
+        _object = static_cast<T*>(other.GetPointer());
+        _refCount = other._refCount;
+        other._object = nullptr;
+        other._refCount = nullptr;
+        return *this;
     }
 
-    constexpr T& operator*() const { return *_pointer; }
-    constexpr T* operator->() const { return _pointer; }
+    T& operator*() const { return *static_cast<T*>(_object); }
+    T* operator->() const { return static_cast<T*>(_object); }
+    T* GetPointer() const { return static_cast<T*>(_object); }
 
-    constexpr T* GetPointer() const { return _pointer; }
-    constexpr u32 GetRefCount() const { return _refCount ? *_refCount : 0; }
-    constexpr bool IsValid() const { return _pointer; }
+    bool IsValid() const { return _object != nullptr; }
+    operator bool() const { return _object != nullptr; }
+
+private:
+    SharedPtr(T* object, RefCount* refCount)
+        : SharedPtrBase(object, refCount) { }
+
+    SharedPtr(T* object, RefCount* refCount, bool doSharedFromThis)
+        : SharedPtrBase(object, refCount)
+    {
+        if (doSharedFromThis)
+        {
+            if constexpr (std::is_convertible<T*, EnableSharedFromThisBase*>::value)
+            {
+                _refCount->weakRefCount = 1;
+                GetPointer()->__SetSharedFromThisWeakPtr(*this);
+            }
+        }
+    }
 };

arm9/source/core/SharedPtrAsm.s

@@ -0,0 +1,15 @@
+.section .itcm
+.arm
+
+// r0 = &refCount
+.global shared_ptr_increase_ref_count
+.type shared_ptr_increase_ref_count, %function
+shared_ptr_increase_ref_count:
+    mrs r2, cpsr
+    orr r1, r2, #0x80
+    msr cpsr_c, r1
+    ldr r12, [r0]
+    add r12, r12, #1
+    str r12, [r0]
+    msr cpsr_c, r2
+    bx lr

arm9/source/core/WeakPtr.cpp

@@ -0,0 +1,35 @@
+#include "common.h"
+#include <libtwl/rtos/rtosIrq.h>
+#include "WeakPtr.h"
+
+void WeakPtrBase::ResetIntern()
+{
+    u32 irq = rtos_disableIrqs();
+    auto refCount = _refCount;
+    if (--refCount->weakRefCount == 0)
+    {
+        _refCount = nullptr;
+        rtos_restoreIrqs(irq);
+        delete refCount;
+    }
+    else
+    {
+        rtos_restoreIrqs(irq);
+    }
+}
+
+bool WeakPtrBase::LockIntern() const
+{
+    u32 irq = rtos_disableIrqs();
+    if (_refCount->refCount != 0)
+    {
+        _refCount->refCount++;
+        rtos_restoreIrqs(irq);
+        return true;
+    }
+    else
+    {
+        rtos_restoreIrqs(irq);
+        return false;
+    }
+}

arm9/source/core/WeakPtr.h

@@ -0,0 +1,158 @@
+#pragma once
+#include <type_traits>
+#include "RefCount.h"
+#include "SharedPtr.h"
+
+class WeakPtrBase
+{
+public:
+    ~WeakPtrBase()
+    {
+        Reset();
+    }
+
+    void Reset()
+    {
+        if (_refCount)
+        {
+            Reset();
+        }
+    }
+
+protected:
+    RefCount* _refCount;
+
+    WeakPtrBase()
+        : _refCount(nullptr) { }
+
+    explicit WeakPtrBase(RefCount* refCount)
+        : _refCount(refCount) { }
+
+    void ResetIntern();
+    bool LockIntern() const;
+};
+
+template <class T>
+class WeakPtr : public WeakPtrBase
+{
+    template <class Y> friend class WeakPtr;
+    template <class Y> friend class EnableSharedFromThis;
+
+public:
+    WeakPtr() { }
+
+    WeakPtr(std::nullptr_t) { }
+
+    WeakPtr(const WeakPtr& other)
+        : WeakPtrBase(other._refCount), _object(other._object)
+    {
+        if (_refCount)
+        {
+            shared_ptr_increase_ref_count(_refCount->weakRefCount);
+        }
+    }
+
+    WeakPtr(WeakPtr&& other)
+        : WeakPtrBase(other._refCount), _object(other._object)
+    {
+        other._refCount = nullptr;
+        other._object = nullptr;
+    }
+
+    template <class Y> requires std::assignable_from<T*&, Y*>
+    WeakPtr(const SharedPtr<Y>& sharedPtr)
+        : WeakPtrBase(sharedPtr._refCount), _object(static_cast<T*>(sharedPtr.GetPointer()))
+    {
+        if (_refCount)
+        {
+            shared_ptr_increase_ref_count(_refCount->weakRefCount);
+        }
+    }
+
+    template <class Y>
+    explicit WeakPtr(const SharedPtr<Y>& sharedPtr)
+        : WeakPtrBase(sharedPtr._refCount), _object(static_cast<T*>(sharedPtr.GetPointer()))
+    {
+        if (_refCount)
+        {
+            shared_ptr_increase_ref_count(_refCount->weakRefCount);
+        }
+    }
+
+    WeakPtr& operator=(const WeakPtr& other)
+    {
+        Reset();
+        _object = other._object;
+        _refCount = other._refCount;
+        if (_refCount)
+        {
+            shared_ptr_increase_ref_count(_refCount->weakRefCount);
+        }
+        return *this;
+    }
+
+    template <class Y> requires std::assignable_from<T*&, Y*>
+    WeakPtr<T>& operator=(const WeakPtr<Y>& other)
+    {
+        Reset();
+        _object = static_cast<T*>(static_cast<Y*>(other._object));
+        _refCount = other._refCount;
+        if (_refCount)
+        {
+            shared_ptr_increase_ref_count(_refCount->weakRefCount);
+        }
+        return *this;
+    }
+
+    template <class Y> requires std::assignable_from<T*&, Y*>
+    WeakPtr<T>& operator=(const SharedPtr<Y>& sharedPtr)
+    {
+        Reset();
+        _object = static_cast<T*>(sharedPtr.GetPointer());
+        _refCount = sharedPtr._refCount;
+        if (_refCount)
+        {
+            shared_ptr_increase_ref_count(_refCount->weakRefCount);
+        }
+        return *this;
+    }
+
+    WeakPtr& operator=(WeakPtr&& other)
+    {
+        Reset();
+        _object = other._object;
+        _refCount = other._refCount;
+        other._object = nullptr;
+        other._refCount = nullptr;
+        return *this;
+    }
+
+    template <class Y> requires std::assignable_from<T*&, Y*>
+    WeakPtr<T>& operator=(WeakPtr<Y>&& other)
+    {
+        Reset();
+        _object = static_cast<T*>(static_cast<Y*>(other._object));
+        _refCount = other._refCount;
+        other._object = nullptr;
+        other._refCount = nullptr;
+        return *this;
+    }
+
+    SharedPtr<T> Lock() const
+    {
+        if (_refCount && LockIntern())
+        {
+            return SharedPtr<T>(_object, _refCount);
+        }
+        else
+        {
+            return SharedPtr<T>();
+        }
+    }
+
+private:
+    T* _object;
+
+    WeakPtr(T* object, RefCount* refCount)
+        : WeakPtrBase(refCount), _object(object) { }
+};