From 7c7b9653f843588ae60d92c6f7d1477d7bbc5f05 Mon Sep 17 00:00:00 2001
From: Stefan Radomski <github@mintwerk.de>
Date: Thu, 15 Dec 2016 16:52:55 +0100
Subject: Prevented overflow with size_t::max for durations

---
 src/uscxml/interpreter/BasicEventQueue.cpp | 20 ++++++++++----------
 src/uscxml/interpreter/InterpreterImpl.h   |  3 ++-
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/src/uscxml/interpreter/BasicEventQueue.cpp b/src/uscxml/interpreter/BasicEventQueue.cpp
index 104c9fa..2f8bd48 100644
--- a/src/uscxml/interpreter/BasicEventQueue.cpp
+++ b/src/uscxml/interpreter/BasicEventQueue.cpp
@@ -22,8 +22,6 @@
 #include <event2/thread.h>
 #include <assert.h>
 
-//#include <iostream>
-
 #include "uscxml/interpreter/Logging.h"
 
 namespace uscxml {
@@ -37,19 +35,21 @@ Event BasicEventQueue::dequeue(size_t blockMs) {
 	std::lock_guard<std::recursive_mutex> lock(_mutex);
 
 	if (blockMs > 0) {
+        using namespace std::chrono;
 
-		// block for given milliseconds or until queue is non-empty
-		auto endTime = std::chrono::system_clock::now() + std::chrono::milliseconds(blockMs);
-//        std::time_t ttp = std::chrono::system_clock::to_time_t(endTime);
-//        std::cout << "End: " << ttp << std::endl;
-//        std::cout << "Now: " << std::chrono::system_clock::to_time_t(std::chrono::system_clock::now()) << std::endl;
+        // TODO: do read http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2661.htm
+        system_clock::time_point now = system_clock::now();
+        system_clock::time_point endTime = now + milliseconds(blockMs);
 
+        // now + milliseconds(blockMs) may not have fitted into a duration type - limit to maximum duration
+        if (blockMs > system_clock::duration::max().count() - duration_cast<milliseconds>(now.time_since_epoch()).count()) {
+            endTime = system_clock::time_point::max();
+        }
+        
+		// block for given milliseconds or until queue is non-empty
 		while (endTime > std::chrono::system_clock::now() && _queue.empty()) {
 			_cond.wait_until(_mutex, endTime);
-//            std::cout << "Aft: " << std::chrono::system_clock::to_time_t(std::chrono::system_clock::now()) << std::endl;
-//            std::cout << blockMs << ".";
 		}
-
 	}
 
 	if (_queue.size() > 0) {
diff --git a/src/uscxml/interpreter/InterpreterImpl.h b/src/uscxml/interpreter/InterpreterImpl.h
index f4fe93e..1243f7c 100644
--- a/src/uscxml/interpreter/InterpreterImpl.h
+++ b/src/uscxml/interpreter/InterpreterImpl.h
@@ -25,6 +25,7 @@
 #include <list>
 #include <map>
 #include <string>
+#include <limits>
 
 #include "uscxml/Common.h"
 #include "uscxml/util/URL.h"
@@ -107,7 +108,7 @@ public:
 	 MicrostepCallbacks
 	 */
 	virtual Event dequeueInternal() {
-		_currEvent = _internalQueue.dequeue(false);
+		_currEvent = _internalQueue.dequeue(0);
 		if (_currEvent)
 			_dataModel.setEvent(_currEvent);
 		return _currEvent;
-- 
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