Class weak_ptr

src/fl/stl/weak_ptr.h:11–194

// std::weak_ptr compatible implementation
template<typename T>
class weak_ptr {
private:
    T* mPtr;
    detail::ControlBlockBase* mControlBlock;

public:
    using element_type = T;
    
    // Default constructor
    weak_ptr() FL_NOEXCEPT : mPtr(nullptr), mControlBlock(nullptr) {}
    
    // Copy constructor
    weak_ptr(const weak_ptr& other) FL_NOEXCEPT : mPtr(other.mPtr), mControlBlock(other.mControlBlock) {
        if (mControlBlock) {
            ++mControlBlock->weak_count;
        }
    }
    
    // Converting copy constructor
    template<typename Y>
    weak_ptr(const weak_ptr<Y>& other) FL_NOEXCEPT : mPtr(other.mPtr), mControlBlock(other.mControlBlock) {
        if (mControlBlock) {
            ++mControlBlock->weak_count;
        }
    }
    
    // Constructor from shared_ptr
    template<typename Y>
    weak_ptr(const shared_ptr<Y>& shared) FL_NOEXCEPT : mPtr(shared.mPtr), mControlBlock(shared.mControlBlock) {
        if (mControlBlock) {
            ++mControlBlock->weak_count;
        }
    }
    
    // Move constructor
    weak_ptr(weak_ptr&& other) FL_NOEXCEPT : mPtr(other.mPtr), mControlBlock(other.mControlBlock) {
        other.mPtr = nullptr;
        other.mControlBlock = nullptr;
    }
    
    // Converting move constructor
    template<typename Y>
    weak_ptr(weak_ptr<Y>&& other) FL_NOEXCEPT : mPtr(other.mPtr), mControlBlock(other.mControlBlock) {
        other.mPtr = nullptr;
        other.mControlBlock = nullptr;
    }
    
    // Destructor
    ~weak_ptr() FL_NOEXCEPT {
        release();
    }
    
    // Assignment operators
    weak_ptr& operator=(const weak_ptr& other) FL_NOEXCEPT {
        if (this != &other) {
            release();
            mPtr = other.mPtr;
            mControlBlock = other.mControlBlock;