feat update

3party/asyncplusplus/include/async++/ref_count.h

@@ -0,0 +1,177 @@
+// Copyright (c) 2015 Amanieu d'Antras
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+#ifndef ASYNCXX_H_
+# error "Do not include this header directly, include <async++.h> instead."
+#endif
+
+namespace async {
+namespace detail {
+
+// Default deleter which just uses the delete keyword
+template<typename T>
+struct default_deleter {
+	static void do_delete(T* p)
+	{
+		delete p;
+	}
+};
+
+// Reference-counted object base class
+template<typename T, typename Deleter = default_deleter<T>>
+struct ref_count_base {
+	std::atomic<std::size_t> ref_count;
+
+	// By default the reference count is initialized to 1
+	explicit ref_count_base(std::size_t count = 1)
+		: ref_count(count) {}
+
+	void add_ref(std::size_t count = 1)
+	{
+		ref_count.fetch_add(count, std::memory_order_relaxed);
+	}
+	void remove_ref(std::size_t count = 1)
+	{
+		if (ref_count.fetch_sub(count, std::memory_order_release) == count) {
+			std::atomic_thread_fence(std::memory_order_acquire);
+			Deleter::do_delete(static_cast<T*>(this));
+		}
+	}
+	void add_ref_unlocked()
+	{
+		ref_count.store(ref_count.load(std::memory_order_relaxed) + 1, std::memory_order_relaxed);
+	}
+	bool is_unique_ref(std::memory_order order)
+	{
+		return ref_count.load(order) == 1;
+	}
+};
+
+// Pointer to reference counted object, based on boost::intrusive_ptr
+template<typename T>
+class ref_count_ptr {
+	T* p;
+
+public:
+	// Note that this doesn't increment the reference count, instead it takes
+	// ownership of a pointer which you already own a reference to.
+	explicit ref_count_ptr(T* t)
+		: p(t) {}
+
+	ref_count_ptr()
+		: p(nullptr) {}
+	ref_count_ptr(std::nullptr_t)
+		: p(nullptr) {}
+	ref_count_ptr(const ref_count_ptr& other) LIBASYNC_NOEXCEPT
+		: p(other.p)
+	{
+		if (p)
+			p->add_ref();
+	}
+	ref_count_ptr(ref_count_ptr&& other) LIBASYNC_NOEXCEPT
+		: p(other.p)
+	{
+		other.p = nullptr;
+	}
+	ref_count_ptr& operator=(std::nullptr_t)
+	{
+		if (p)
+			p->remove_ref();
+		p = nullptr;
+		return *this;
+	}
+	ref_count_ptr& operator=(const ref_count_ptr& other) LIBASYNC_NOEXCEPT
+	{
+		if (p) {
+			p->remove_ref();
+			p = nullptr;
+		}
+		p = other.p;
+		if (p)
+			p->add_ref();
+		return *this;
+	}
+	ref_count_ptr& operator=(ref_count_ptr&& other) LIBASYNC_NOEXCEPT
+	{
+		if (p) {
+			p->remove_ref();
+			p = nullptr;
+		}
+		p = other.p;
+		other.p = nullptr;
+		return *this;
+	}
+	~ref_count_ptr()
+	{
+		if (p)
+			p->remove_ref();
+	}
+
+	T& operator*() const
+	{
+		return *p;
+	}
+	T* operator->() const
+	{
+		return p;
+	}
+	T* get() const
+	{
+		return p;
+	}
+	T* release()
+	{
+		T* out = p;
+		p = nullptr;
+		return out;
+	}
+
+	explicit operator bool() const
+	{
+		return p != nullptr;
+	}
+	friend bool operator==(const ref_count_ptr& a, const ref_count_ptr& b)
+	{
+		return a.p == b.p;
+	}
+	friend bool operator!=(const ref_count_ptr& a, const ref_count_ptr& b)
+	{
+		return a.p != b.p;
+	}
+	friend bool operator==(const ref_count_ptr& a, std::nullptr_t)
+	{
+		return a.p == nullptr;
+	}
+	friend bool operator!=(const ref_count_ptr& a, std::nullptr_t)
+	{
+		return a.p != nullptr;
+	}
+	friend bool operator==(std::nullptr_t, const ref_count_ptr& a)
+	{
+		return a.p == nullptr;
+	}
+	friend bool operator!=(std::nullptr_t, const ref_count_ptr& a)
+	{
+		return a.p != nullptr;
+	}
+};
+
+} // namespace detail
+} // namespace async