116 lines
2.5 KiB
C++
116 lines
2.5 KiB
C++
#ifndef ref_ptr_hh_INCLUDED
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#define ref_ptr_hh_INCLUDED
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#include <utility>
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namespace Kakoune
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{
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struct RefCountable
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{
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int refcount = 0;
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virtual ~RefCountable() = default;
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};
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struct RefCountablePolicy
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{
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static void inc_ref(RefCountable* r, void*) noexcept { ++r->refcount; }
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static void dec_ref(RefCountable* r, void*) { if (--r->refcount == 0) delete r; }
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static void ptr_moved(RefCountable*, void*, void*) noexcept {}
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};
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template<typename T, typename Policy = RefCountablePolicy>
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struct RefPtr
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{
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RefPtr() = default;
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explicit RefPtr(T* ptr) : m_ptr(ptr) { acquire(); }
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~RefPtr() { release(); }
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RefPtr(const RefPtr& other) : m_ptr(other.m_ptr) { acquire(); }
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RefPtr(RefPtr&& other)
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noexcept(noexcept(std::declval<RefPtr>().moved(nullptr)))
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: m_ptr(other.m_ptr) { other.m_ptr = nullptr; moved(&other); }
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RefPtr& operator=(const RefPtr& other)
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{
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if (other.m_ptr != m_ptr)
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{
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release();
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m_ptr = other.m_ptr;
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acquire();
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}
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return *this;
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}
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RefPtr& operator=(RefPtr&& other)
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{
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release();
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m_ptr = other.m_ptr;
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other.m_ptr = nullptr;
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moved(&other);
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return *this;
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}
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RefPtr& operator=(T* ptr)
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{
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if (ptr != m_ptr)
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{
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release();
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m_ptr = ptr;
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acquire();
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}
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return *this;
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}
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[[gnu::always_inline]]
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T* operator->() const { return m_ptr; }
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[[gnu::always_inline]]
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T& operator*() const { return *m_ptr; }
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[[gnu::always_inline]]
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T* get() const { return m_ptr; }
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[[gnu::always_inline]]
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explicit operator bool() const { return m_ptr; }
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void reset(T* ptr = nullptr)
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{
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if (ptr == m_ptr)
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return;
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release();
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m_ptr = ptr;
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acquire();
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}
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friend bool operator==(const RefPtr& lhs, const RefPtr& rhs) { return lhs.m_ptr == rhs.m_ptr; }
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friend bool operator!=(const RefPtr& lhs, const RefPtr& rhs) { return lhs.m_ptr != rhs.m_ptr; }
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private:
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T* m_ptr = nullptr;
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[[gnu::always_inline]]
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void acquire()
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{
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if (m_ptr)
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Policy::inc_ref(m_ptr, this);
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}
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[[gnu::always_inline]]
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void release()
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{
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if (m_ptr)
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Policy::dec_ref(m_ptr, this);
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}
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[[gnu::always_inline]]
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void moved(void* from)
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noexcept(noexcept(Policy::ptr_moved(nullptr, nullptr, nullptr)))
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{
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if (m_ptr)
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Policy::ptr_moved(m_ptr, from, this);
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}
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};
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}
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#endif // ref_ptr_hh_INCLUDED
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