nearby: snapshot as of cl/296436629

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

cpp/platform/api/submittable_executor.h

@@ -0,0 +1,43 @@
+#ifndef PLATFORM_API_SUBMITTABLE_EXECUTOR_H_
+#define PLATFORM_API_SUBMITTABLE_EXECUTOR_H_
+
+#include "platform/api/executor.h"
+#include "platform/api/future.h"
+#include "platform/callable.h"
+#include "platform/port/down_cast.h"
+#include "platform/ptr.h"
+#include "platform/runnable.h"
+
+namespace location {
+namespace nearby {
+
+// Each per-platform concrete implementation is expected to extend from
+// SubmittableExecutor and provide an override of its submit() method.
+//
+// e.g.
+// class IOSSubmittableExecutor
+//                      : public SubmittableExecutor<IOSSubmittableExecutor> {
+//  public:
+//   template <typename T>
+//   Ptr<Future<T> > submit(Ptr<Callable<T> > callable) {
+//     ...
+//   }
+// }
+template <typename ConcreteSubmittableExecutor>
+class SubmittableExecutor : public Executor {
+ public:
+  ~SubmittableExecutor() override {}
+
+  template <typename T>
+  Ptr<Future<T> > submit(Ptr<Callable<T> > callable) {
+    return DOWN_CAST<ConcreteSubmittableExecutor*>(this)->submit(callable);
+  }
+
+  // https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/Executor.html#execute-java.lang.Runnable-
+  virtual void execute(Ptr<Runnable> runnable) = 0;
+};
+
+}  // namespace nearby
+}  // namespace location
+
+#endif  // PLATFORM_API_SUBMITTABLE_EXECUTOR_H_