Initial public release of nearby library

Signed-off-by: Alexey Polyudov <apolyudov@google.com>
Change-Id: I85d490e448375aa4eb7b09680757c02fff1420b4

cpp/core/internal/loop_runner.h

@@ -0,0 +1,56 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#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_