cancellation refactoring

ixwebsocket/IXCancellationRequest.cpp

@@ -0,0 +1,33 @@
+/*
+ *  IXCancellationRequest.cpp
+ *  Author: Benjamin Sergeant
+ *  Copyright (c) 2019 Machine Zone, Inc. All rights reserved.
+ */
+
+#include "IXCancellationRequest.h"
+
+#include <chrono>
+
+namespace ix 
+{
+    CancellationRequest makeCancellationRequestWithTimeout(int secs,
+                                                           std::atomic<bool>& requestInitCancellation)
+    {
+        auto start = std::chrono::system_clock::now();
+        auto timeout = std::chrono::seconds(secs);
+
+        auto isCancellationRequested = [&requestInitCancellation, start, timeout]() -> bool
+        {
+            // Was an explicit cancellation requested ?
+            if (requestInitCancellation) return true;
+            
+            auto now = std::chrono::system_clock::now();
+            if ((now - start) > timeout) return true;
+
+            // No cancellation request
+            return false;
+        };
+
+        return isCancellationRequested;
+    }
+}