thread/Cond: add timed_wait() overload with std::chrono support

src/thread/PosixCond.hxx

@@ -32,6 +32,8 @@
 
 #include "PosixMutex.hxx"
 
+#include <chrono>
+
 #include <sys/time.h>
 
 /**
@@ -87,6 +89,17 @@ public:
 
 		return pthread_cond_timedwait(&cond, &mutex.mutex, &ts) == 0;
 	}
+
+	bool timed_wait(PosixMutex &mutex,
+			std::chrono::steady_clock::duration timeout) {
+		auto timeout_ms = std::chrono::duration_cast<std::chrono::milliseconds>(timeout).count();
+		if (timeout_ms < 0)
+			timeout_ms = 0;
+		else if (timeout_ms > std::numeric_limits<unsigned>::max())
+			timeout_ms = std::numeric_limits<unsigned>::max();
+
+		return timed_wait(mutex, timeout_ms);
+	}
 };
 
 #endif

src/thread/WindowsCond.hxx

@@ -32,6 +32,8 @@
 
 #include "CriticalSection.hxx"
 
+#include <chrono>
+
 /**
  * Wrapper for a CONDITION_VARIABLE, backend for the Cond class.
  */
@@ -59,6 +61,12 @@ public:
 						timeout_ms);
 	}
 
+	bool timed_wait(CriticalSection &mutex,
+			std::chrono::steady_clock::duration timeout) {
+		auto timeout_ms = std::chrono::duration_cast<std::chrono::milliseconds>(timeout).count();
+		return timed_wait(mutex, timeout_ms);
+	}
+
 	void wait(CriticalSection &mutex) {
 		timed_wait(mutex, INFINITE);
 	}