1 files changed, 78 insertions, 8 deletions
diff --git a/common/atomic.h b/common/atomic.h
index 5e9b04c6..e85c4f76 100644
--- a/common/atomic.h
+++ b/common/atomic.h
@@ -2,17 +2,16 @@
 #define AL_ATOMIC_H
 
 #include <atomic>
+#include <memory>
 
+#include "almalloc.h"
 
-using RefCount = std::atomic<unsigned int>;
-
-inline void InitRef(RefCount &ref, unsigned int value)
-{ ref.store(value, std::memory_order_relaxed); }
-inline unsigned int ReadRef(RefCount &ref)
-{ return ref.load(std::memory_order_acquire); }
-inline unsigned int IncrementRef(RefCount &ref)
+template<typename T>
+auto IncrementRef(std::atomic<T> &ref) noexcept
 { return ref.fetch_add(1u, std::memory_order_acq_rel)+1u; }
-inline unsigned int DecrementRef(RefCount &ref)
+
+template<typename T>
+auto DecrementRef(std::atomic<T> &ref) noexcept
 { return ref.fetch_sub(1u, std::memory_order_acq_rel)-1u; }
 
 
@@ -30,4 +29,75 @@ inline void AtomicReplaceHead(std::atomic<T> &head, T newhead)
             std::memory_order_acq_rel, std::memory_order_acquire));
 }
 
+namespace al {
+
+template<typename T, typename D=std::default_delete<T>>
+class atomic_unique_ptr {
+    std::atomic<gsl::owner<T*>> mPointer{};
+
+    using unique_ptr_t = std::unique_ptr<T,D>;
+
+public:
+    atomic_unique_ptr() = default;
+    atomic_unique_ptr(const atomic_unique_ptr&) = delete;
+    explicit atomic_unique_ptr(std::nullptr_t) noexcept { }
+    explicit atomic_unique_ptr(gsl::owner<T*> ptr) noexcept : mPointer{ptr} { }
+    explicit atomic_unique_ptr(unique_ptr_t&& rhs) noexcept : mPointer{rhs.release()} { }
+    ~atomic_unique_ptr()
+    {
+        if(auto ptr = mPointer.exchange(nullptr, std::memory_order_relaxed))
+            D{}(ptr);
+    }
+
+    auto operator=(const atomic_unique_ptr&) -> atomic_unique_ptr& = delete;
+    auto operator=(std::nullptr_t) noexcept -> atomic_unique_ptr&
+    {
+        if(auto ptr = mPointer.exchange(nullptr))
+            D{}(ptr);
+        return *this;
+    }
+    auto operator=(unique_ptr_t&& rhs) noexcept -> atomic_unique_ptr&
+    {
+        if(auto ptr = mPointer.exchange(rhs.release()))
+            D{}(ptr);
+        return *this;
+    }
+
+    [[nodiscard]]
+    auto load(std::memory_order m=std::memory_order_seq_cst) const noexcept -> T*
+    { return mPointer.load(m); }
+    void store(std::nullptr_t, std::memory_order m=std::memory_order_seq_cst) noexcept
+    {
+        if(auto oldptr = mPointer.exchange(nullptr, m))
+            D{}(oldptr);
+    }
+    void store(gsl::owner<T*> ptr, std::memory_order m=std::memory_order_seq_cst) noexcept
+    {
+        if(auto oldptr = mPointer.exchange(ptr, m))
+            D{}(oldptr);
+    }
+    void store(unique_ptr_t&& ptr, std::memory_order m=std::memory_order_seq_cst) noexcept
+    {
+        if(auto oldptr = mPointer.exchange(ptr.release(), m))
+            D{}(oldptr);
+    }
+
+    [[nodiscard]]
+    auto exchange(std::nullptr_t, std::memory_order m=std::memory_order_seq_cst) noexcept -> unique_ptr_t
+    { return unique_ptr_t{mPointer.exchange(nullptr, m)}; }
+    [[nodiscard]]
+    auto exchange(gsl::owner<T*> ptr, std::memory_order m=std::memory_order_seq_cst) noexcept -> unique_ptr_t
+    { return unique_ptr_t{mPointer.exchange(ptr, m)}; }
+    [[nodiscard]]
+    auto exchange(std::unique_ptr<T>&& ptr, std::memory_order m=std::memory_order_seq_cst) noexcept -> unique_ptr_t
+    { return unique_ptr_t{mPointer.exchange(ptr.release(), m)}; }
+
+    [[nodiscard]]
+    auto is_lock_free() const noexcept -> bool { return mPointer.is_lock_free(); }
+
+    static constexpr auto is_always_lock_free = std::atomic<gsl::owner<T*>>::is_always_lock_free;
+};
+
+} // namespace al
+
 #endif /* AL_ATOMIC_H */