150 lines
3.3 KiB
C++
150 lines
3.3 KiB
C++
/*
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* Copyright (c) 2012, 2013, 2014, 2017 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* sortix/kernel/refcount.h
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* A class that implements reference counting.
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*/
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#ifndef SORTIX_REFCOUNT_H
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#define SORTIX_REFCOUNT_H
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#include <sortix/kernel/kthread.h>
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namespace Sortix {
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class Refcountable
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{
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public:
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Refcountable();
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virtual ~Refcountable();
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public:
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void Refer_Renamed();
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void Unref_Renamed();
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size_t Refcount() const { return refcount; }
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bool IsUnique() const { return refcount == 1; }
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private:
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kthread_mutex_t reflock;
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size_t refcount;
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public:
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bool being_deleted;
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};
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template <class T> class Ref
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{
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public:
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constexpr Ref() : obj(NULL) { }
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explicit Ref(T* obj) : obj(obj) { if ( obj ) obj->Refer_Renamed(); }
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template <class U>
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explicit Ref(U* obj) : obj(obj) { if ( obj ) obj->Refer_Renamed(); }
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Ref(const Ref<T>& r) : obj(r.Get()) { if ( obj ) obj->Refer_Renamed(); }
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template <class U>
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Ref(const Ref<U>& r) : obj(r.Get()) { if ( obj ) obj->Refer_Renamed(); }
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~Ref() { if ( obj ) obj->Unref_Renamed(); }
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Ref& operator=(const Ref r)
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{
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if ( obj == r.Get() )
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return *this;
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if ( obj )
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{
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obj->Unref_Renamed();
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obj = NULL;
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}
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if ( (obj = r.Get()) )
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obj->Refer_Renamed();
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return *this;
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}
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template <class U>
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Ref operator=(const Ref<U> r)
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{
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if ( obj == r.Get() )
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return *this;
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if ( obj )
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{
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obj->Unref_Renamed();
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obj = NULL;
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}
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if ( (obj = r.Get()) )
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obj->Refer_Renamed();
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return *this;
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}
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bool operator==(const Ref& other)
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{
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return (*this).Get() == other.Get();
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}
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template <class U> bool operator==(const Ref<U>& other)
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{
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return (*this).Get() == other.Get();
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}
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template <class U> bool operator==(const U* const& other)
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{
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return (*this).Get() == other;
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}
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bool operator!=(const Ref& other)
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{
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return !((*this) == other);
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}
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template <class U> bool operator!=(const Ref<U>& other)
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{
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return !((*this) == other);
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}
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template <class U> bool operator!=(const U* const& other)
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{
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return !((*this) == other);
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}
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void Reset() { if ( obj ) obj->Unref_Renamed(); obj = NULL; }
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T* Get() const { return obj; }
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T& operator *() const { return *obj; }
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T* operator->() const { return obj; }
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operator bool() const { return obj != NULL; }
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size_t Refcount() const { return obj ? obj->Refcount : 0; }
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bool IsUnique() const { return obj->IsUnique(); }
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// Leak a reference and allow recreating it later from an integer.
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uintptr_t Export()
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{
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if ( obj )
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obj->Refer_Renamed();
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return (uintptr_t) obj;
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}
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// Restore a leaked reference from an integer.
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void Import(uintptr_t ptr)
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{
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Reset();
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obj = (T*) ptr;
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}
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private:
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T* obj;
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};
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} // namespace Sortix
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#endif
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