Roll forward to cl/338482889

Signed-off-by: Alexey Polyudov <apolyudov@google.com>
Change-Id: Ic2bdb234e89f3c5860d1b483dd4bce689f13d057

cpp/platform/api/submittable_executor.h

@@ -16,40 +16,31 @@
 #define PLATFORM_API_SUBMITTABLE_EXECUTOR_H_
 
 #include <functional>
+#include <memory>
 
 #include "platform/api/executor.h"
 #include "platform/api/future.h"
-#include "platform/api/platform.h"
-#include "platform/api/settable_future.h"
-#include "platform/api/submittable_executor_def.h"
-#include "platform/exception.h"
+#include "platform/base/runnable.h"
 
 namespace location {
 namespace nearby {
+namespace api {
 
-// "Common" part of implementation.
-// Placed here for textual compatibility to minimize scope of changes.
-// Can be (and should be) moved to a separate file outside "api" folder.
-// TODO(apolyudov): for API v2.0
-template <typename T>
-Ptr<Future<T>> SubmittableExecutor::submit(Ptr<Callable<T>> callable) {
-  using Platform = platform::ImplementationPlatform;
-  Ptr<SettableFuture<T>> future{Platform::createSettableFuture<T>()};
-  bool submitted = DoSubmit([callable, future]() {
-    ExceptionOr<T> result = callable->call();
-    if (result.ok()) {
-      future->set(std::move(result.result()));
-    } else {
-      future->setException({result.exception()});
-    }
-  });
-  if (!submitted) {
-    // Raise Exception::kExecution if we are shutting down.
-    future->setException({Exception::kExecution});
-  }
-  return future;
-}
+// Main interface to be used by platform as a base class for
+// - MultiThreadExecutorWrapper
+// - SingleThreadExecutorWrapper
+// Platform must override bool submit(std::function<void()>) method.
+class SubmittableExecutor : public Executor {
+ public:
+  ~SubmittableExecutor() override = default;
 
+  // Submit a callable (with no delay).
+  // Returns true, if callable was submitted, false otherwise.
+  // Callable is not submitted if shutdown is in progress.
+  virtual bool DoSubmit(Runnable&& wrapped_callable) = 0;
+};
+
+}  // namespace api
 }  // namespace nearby
 }  // namespace location