text: /*
   * Copyright (C) 2018 The Android Open Source Project
   *
   * 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
   *
   *      http://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 TEST_TASK_RUNNER_THREAD_H_
  #define TEST_TASK_RUNNER_THREAD_H_
  
  #include <condition_variable>
  #include <mutex>
  #include <thread>
  
  #include "perfetto/base/task_runner.h"
  #include "src/base/test/test_task_runner.h"
  
  namespace perfetto {
  
  // Used to perform initialization work on a background TaskRunnerThread.
  class ThreadDelegate {
   public:
    virtual ~ThreadDelegate();
  
    // Invoked on the target thread before the message loop is started.
    virtual void Initialize(base::TaskRunner* task_runner) = 0;
  };
  
  // Background thread which spins a task runner until completed or the thread is
  // destroyed. If the thread is destroyed before the task runner completes, the
  // task runner is quit and the thread is joined.
  class TaskRunnerThread {
   public:
    explicit TaskRunnerThread(const char* name);
    ~TaskRunnerThread();
  
    // Blocks until the thread has been created and Initialize() has been
    // called.
    void Start(std::unique_ptr<ThreadDelegate> delegate);
  
    // Blocks until the thread has been stopped and joined.
    void Stop();
  
    uint64_t GetThreadCPUTimeNs();
  
   private:
    void Run(std::unique_ptr<ThreadDelegate> delegate);
  
    const char* const name_;
    std::thread thread_;
    std::condition_variable ready_;
  
    // All variables below this point are protected by |mutex_|.
    std::mutex mutex_;
    base::UnixTaskRunner* runner_ = nullptr;
  };
  
  }  // namespace perfetto
  
  #endif  // TEST_TASK_RUNNER_THREAD_H_
  