mirror of
https://github.com/jart/cosmopolitan.git
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weak_ptr, conform more closely to the STL
Just write out the constructor definitions on cppreference.com. Make the private constructor from a raw rc into a static private method instead of a private constructor. Various other minor fixes.
This commit is contained in:
Steven Dee (Jōshin)
parent
3c88e616b0
commit
b86808c617
2 changed files with 204 additions and 25 deletions
223
ctl/shared_ptr.h
223
ctl/shared_ptr.h
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@ -129,28 +129,80 @@ struct bad_weak_ptr : ctl::exception
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}
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};
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template<typename T, typename D = default_delete<T>>
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template<typename T>
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class weak_ptr;
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template<typename T>
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class shared_ptr
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{
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public:
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using element_type = T; // TODO(mrdomino): remove extent?
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using deleter_type = D;
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using element_type = T; // TODO(mrdomino): remove extent
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using weak_type = weak_ptr<T>;
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constexpr shared_ptr(nullptr_t = nullptr) noexcept : p(nullptr), rc(nullptr)
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constexpr shared_ptr() noexcept : p(nullptr), rc(nullptr)
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{
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}
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explicit shared_ptr(auto* const p)
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: p(p), rc(__::shared_pointer<T, D>::make(p, D()))
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constexpr shared_ptr(nullptr_t) noexcept : p(nullptr), rc(nullptr)
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{
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}
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template<typename U>
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requires is_convertible_v<U, T>
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explicit shared_ptr(U* const p)
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: p(p)
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, rc(__::shared_pointer<T, default_delete<T>>::make(p,
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default_delete<T>()))
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{
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}
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template<typename U, typename D>
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requires is_convertible_v<U, T>
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shared_ptr(U* const p, D d)
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: p(p), rc(__::shared_pointer<T, D>::make(p, ctl::move(d)))
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{
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}
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template<typename D>
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shared_ptr(nullptr_t, D d)
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: p(nullptr), rc(__::shared_pointer<T, D>::make(nullptr, ctl::move(d)))
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{
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}
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// TODO(mrdomino): allocators
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template<typename U>
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requires is_convertible_v<U, T>
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shared_ptr(const shared_ptr<U>& r, element_type* const p) noexcept
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: p(p), rc(r.rc)
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{
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if (rc)
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rc->keep_shared();
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}
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template<typename U>
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requires is_convertible_v<U, T>
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shared_ptr(shared_ptr<U>&& r, element_type* const p) noexcept
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: p(p), rc(r.rc)
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{
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r.p = nullptr;
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r.rc = nullptr;
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}
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shared_ptr(const shared_ptr& r) noexcept : p(r.p), rc(r.rc)
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{
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if (rc)
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rc->keep_shared();
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}
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template<typename U>
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requires is_convertible_v<U, T>
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shared_ptr(const shared_ptr<U>& r) noexcept : p(r.p), rc(r.rc)
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{
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if (rc)
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rc->keep_shared();
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}
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shared_ptr(shared_ptr&& r) noexcept : p(r.p), rc(r.rc)
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{
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r.p = nullptr;
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@ -158,20 +210,30 @@ class shared_ptr
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}
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template<typename U>
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shared_ptr(const shared_ptr<U>& r, T* const p) noexcept : p(p), rc(r.rc)
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{
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if (rc)
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rc->keep_shared();
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}
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template<typename U>
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shared_ptr(shared_ptr<U>&& r, T* const p) noexcept : p(p), rc(r.rc)
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requires is_convertible_v<U, T>
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shared_ptr(shared_ptr<U>&& r) noexcept : p(r.p), rc(r.rc)
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{
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r.p = nullptr;
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r.rc = nullptr;
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}
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// TODO(mrdomino): moar ctors
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template<typename U>
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requires is_convertible_v<U, T>
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explicit shared_ptr(const weak_ptr<U>& r) : p(r.p), rc(r.rc)
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{
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// XXX keep_shared?
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if (r.expired())
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// XXX throw bad_weak_ptr?
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__builtin_trap();
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}
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template<typename U, typename D>
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requires is_convertible_v<U, T>
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shared_ptr(unique_ptr<U, D> r)
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: p(r.get()), rc(__::shared_pointer<U, D>::make(r.get(), r.get_deleter()))
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{
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r.release();
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}
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~shared_ptr()
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{
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@ -185,6 +247,15 @@ class shared_ptr
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return *this;
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}
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template<typename U>
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requires is_convertible_v<U, T>
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shared_ptr& operator=(shared_ptr<U> r) noexcept
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{
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swap(p, r.p);
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swap(rc, r.rc);
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return *this;
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}
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void reset() noexcept
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{
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if (rc)
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@ -210,9 +281,8 @@ class shared_ptr
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return p;
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}
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template <typename U = T>
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typename enable_if<!is_void_v<U>, U&>::type
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operator*() const noexcept
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template<typename U = T>
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typename enable_if<!is_void_v<U>, U&>::type operator*() const noexcept
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{
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if (!p)
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__builtin_trap();
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@ -227,9 +297,8 @@ class shared_ptr
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return *p;
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}
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template <typename U = T>
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typename enable_if<!is_void_v<U>, U&>::type
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operator[](ptrdiff_t i) const
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template<typename U = T>
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typename enable_if<!is_void_v<U>, U&>::type operator[](ptrdiff_t i) const
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{
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return *(p + i);
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}
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@ -253,17 +322,121 @@ class shared_ptr
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// TODO(mrdomino): owner_before(weak_ptr const&)
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private:
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constexpr shared_ptr(T* const p, __::shared_control* rc) noexcept
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: p(p), rc(rc)
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static shared_ptr<T> make_from_rc(T* const p,
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__::shared_control* rc) noexcept
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{
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shared_ptr<T> r;
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r.p = p;
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r.rc = rc;
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return r;
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}
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template <typename U, typename E>
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template<typename U>
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friend class shared_ptr;
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template<typename U, typename... Args>
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friend shared_ptr<U> make_shared(Args&&... args);
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template<typename U>
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friend class weak_ptr;
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T* p;
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__::shared_control* rc;
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};
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template<typename T>
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class weak_ptr
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{
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public:
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using element_type = T; // TODO(mrdomino): remove extent
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constexpr weak_ptr() noexcept : p(nullptr), rc(nullptr)
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{
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}
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weak_ptr(const weak_ptr& r) noexcept : p(r.p), rc(r.rc)
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{
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if (rc)
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rc->keep_weak();
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}
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template<typename U>
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requires is_convertible_v<U, T>
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weak_ptr(const weak_ptr<U>& r) noexcept : p(r.p), rc(r.rc)
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{
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if (rc)
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rc->keep_weak();
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}
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template<typename U>
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requires is_convertible_v<U, T>
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weak_ptr(const shared_ptr<U>& r) noexcept : p(r.p), rc(r.rc)
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{
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if (rc)
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rc->keep_weak();
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}
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weak_ptr(weak_ptr&& r) noexcept : p(r.p), rc(r.rc)
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{
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r.p = nullptr;
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r.rc = nullptr;
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}
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template<typename U>
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requires is_convertible_v<U, T>
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weak_ptr(weak_ptr<U>&& r) noexcept : p(r.p), rc(r.rc)
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{
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r.p = nullptr;
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r.rc = nullptr;
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}
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~weak_ptr()
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{
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if (rc)
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rc->drop_weak();
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}
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weak_ptr& operator=(weak_ptr r) noexcept
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{
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swap(r);
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return *this;
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}
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template<typename U>
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requires is_convertible_v<U, T>
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weak_ptr& operator=(weak_ptr<U> r) noexcept
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{
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swap(p, r.p);
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swap(rc, r.rc);
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return *this;
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}
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void reset() noexcept
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{
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if (rc)
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rc->drop_shared();
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p = nullptr;
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rc = nullptr;
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}
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void swap(weak_ptr& r) noexcept
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{
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using ctl::swap;
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swap(p, r.p);
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swap(rc, r.rc);
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}
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size_t use_count() const noexcept
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{
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return rc ? rc->use_count() : 0;
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}
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bool expired() const noexcept
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{
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return use_count() == 0;
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}
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private:
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T* p;
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__::shared_control* rc;
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};
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@ -274,7 +447,7 @@ make_shared(Args&&... args)
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{
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auto rc = __::shared_emplace<T>::make_unique();
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rc->construct(ctl::forward<Args>(args)...);
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auto r = shared_ptr<T>(&rc->t, rc.get());
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auto r = shared_ptr<T>::make_from_rc(&rc->t, rc.get());
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rc.release();
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return r;
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}
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@ -17,6 +17,7 @@
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// PERFORMANCE OF THIS SOFTWARE.
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#include "ctl/shared_ptr.h"
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#include "ctl/utility.h"
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#include "libc/mem/leaks.h"
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#include "libc/runtime/runtime.h"
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@ -75,6 +76,11 @@ main()
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return 8;
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}
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{
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auto x = Mk<int>(5);
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auto y = Ptr(ctl::move(x));
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}
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// TODO(mrdomino): exercise more of API
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// TODO(mrdomino): threading stress-test
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