Implemented submittable_executor and some other missed files

A file was named wrong. It was changed.

internal/platform/implementation/linux/submittable_executor.h

@@ -0,0 +1,53 @@
+// 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 PLATFORM_IMPL_LINUX_SUBMITTABLE_EXECUTOR_H_
+#define PLATFORM_IMPL_LINUX_SUBMITTABLE_EXECUTOR_H_
+
+#include "internal/platform/implementation/submittable_executor.h"
+#include "internal/platform/implementation/linux/executor.h"
+
+namespace nearby {
+namespace linux {
+
+// Main interface to be used by platform as a base class for
+// - MultiThreadExecutorWrapper
+// - SingleThreadExecutorWrapper
+// Platform must override bool submit(absl::AnyInvocable<void()>) method.
+class SubmittableExecutor : public api::SubmittableExecutor {
+ public:
+  SubmittableExecutor();
+  SubmittableExecutor(int32_t maxConcurrancy);
+  ~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.
+  bool DoSubmit(Runnable&& wrapped_callable) override;
+
+  // https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/Executor.html#execute-java.lang.Runnable-
+  void Execute(Runnable&& runnable) override;
+
+  // https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/ExecutorService.html#shutdown--
+  void Shutdown() override;
+
+ private:
+  std::unique_ptr<nearby::linux::Executor> executor_;
+  std::atomic_bool shut_down_ = false;
+};
+
+}  // namespace linux
+}  // namespace nearby
+
+#endif  // PLATFORM_IMPL_LINUX_SUBMITTABLE_EXECUTOR_H_