nearby: snapshot as of cl/296436629

Signed-off-by: Alexey Polyudov <apolyudov@google.com>
Change-Id: I2cf5bf225b76f4c1541954651f3a7544a14e0cec

cpp/core/internal/loop_runner.h

@@ -0,0 +1,42 @@
+#ifndef CORE_INTERNAL_LOOP_RUNNER_H_
+#define CORE_INTERNAL_LOOP_RUNNER_H_
+
+#include "platform/callable.h"
+#include "platform/exception.h"
+#include "platform/port/string.h"
+#include "platform/ptr.h"
+
+namespace location {
+namespace nearby {
+namespace connections {
+
+// Construct to run a loop repeatedly. This class is useful to increase
+// testability for multi-threaded code that runs loops; it shouldn't be used for
+// general purpose loops unless tests require fine-grained control over the
+// looping procedure.
+class LoopRunner {
+ public:
+  explicit LoopRunner(const std::string& name);
+
+  // Runs the provided callable repeatedly until it returns false.
+  //
+  // @return true if the loop completed successfully, false if an exception was
+  // encountered.
+  bool loop(Ptr<Callable<bool> > callable);
+
+ protected:
+  void onEnterLoop();
+  void onEnterIteration();
+  void onExitIteration();
+  void onExitLoop();
+  void onExceptionExitLoop(Exception::Value exception);
+
+ private:
+  const std::string name_;
+};
+
+}  // namespace connections
+}  // namespace nearby
+}  // namespace location
+
+#endif  // CORE_INTERNAL_LOOP_RUNNER_H_