peridot/public/lib/modular_test_harness/cpp/test_harness_launcher.h

// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef LIB_MODULAR_TEST_HARNESS_CPP_TEST_HARNESS_LAUNCHER_H_
#define LIB_MODULAR_TEST_HARNESS_CPP_TEST_HARNESS_LAUNCHER_H_

#include <fuchsia/modular/testing/cpp/fidl.h>
#include <lib/async-loop/cpp/loop.h>
#include <lib/sys/cpp/component_context.h>
#include <lib/sys/cpp/service_directory.h>

#include <condition_variable>
#include <thread>

namespace modular {
namespace testing {

// TestHarnessLauncher launches and manages an instance of the modular test
// harness component. Use this class to acquire an instance of the
// |fuchsia.modular.TestHarness| service.
class TestHarnessLauncher final {
 public:
  // Launches the modular test harness component.
  TestHarnessLauncher();

  // Blocks the current thread until the modular test harness component is
  // destroyed.
  ~TestHarnessLauncher();

  fuchsia::modular::testing::TestHarnessPtr& test_harness() {
    return test_harness_;
  }

 private:
  void LaunchTestHarness(
      fidl::InterfaceRequest<fuchsia::modular::testing::TestHarness>);

  std::shared_ptr<sys::ServiceDirectory> test_harness_svc_;
  fuchsia::sys::ComponentControllerPtr test_harness_ctrl_;
  fuchsia::modular::testing::TestHarnessPtr test_harness_;

  // In order to avoid depending on the owning thread's run loop, the test
  // harness component is launched and managed in a separate thread which
  // contains its own async loop.
  async::Loop* test_harness_loop_ = nullptr;
  // protects |test_harness_loop_|
  std::mutex test_harness_loop_mutex_;
  // used to signal when |test_harness_loop_| !=
  // nullptr
  std::condition_variable test_harness_loop_cv_;
  // IMPORTANT: To avoid racy uninitialized access, this thread should be
  // initialized *after* all of the member variables it uses are initialized.
  std::unique_ptr<std::thread> harness_launcher_thread_;
};

}  // namespace testing
}  // namespace modular

#endif  // LIB_MODULAR_TEST_HARNESS_CPP_TEST_HARNESS_LAUNCHER_H_