feat update

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

@@ -0,0 +1,68 @@
+// 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 {
+
+// Exception thrown by cancel_current_task()
+struct LIBASYNC_EXPORT_EXCEPTION task_canceled {};
+
+// A flag which can be used to request cancellation
+class cancellation_token {
+	std::atomic<bool> state;
+
+public:
+	cancellation_token()
+		: state(false) {}
+
+	// Non-copyable and non-movable
+	cancellation_token(const cancellation_token&) = delete;
+	cancellation_token& operator=(const cancellation_token&) = delete;
+
+	bool is_canceled() const
+	{
+		bool s = state.load(std::memory_order_relaxed);
+		if (s)
+			std::atomic_thread_fence(std::memory_order_acquire);
+		return s;
+	}
+
+	void cancel()
+	{
+		state.store(true, std::memory_order_release);
+	}
+
+	void reset()
+	{
+		state.store(false, std::memory_order_relaxed);
+	}
+};
+
+// Interruption point, throws task_canceled if the specified token is set.
+inline void interruption_point(const cancellation_token& token)
+{
+	if (token.is_canceled())
+		LIBASYNC_THROW(task_canceled());
+}
+
+} // namespace async