// Copyright 2016 The Chromium 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 CHROME_BROWSER_CHROMEOS_BASE_FILE_FLUSHER_H_
#define CHROME_BROWSER_CHROMEOS_BASE_FILE_FLUSHER_H_

#include <vector>

#include "base/callback.h"
#include "base/files/file_path.h"
#include "base/macros.h"
#include "base/memory/weak_ptr.h"

namespace chromeos {

// Flushes files under the requested directories in the blocking pool. If the
// same directory is requested more than once, the last request cancels all
// previous ones and start a new flushing process.
class FileFlusher {
 public:
  FileFlusher();
  ~FileFlusher();

  // Flush everything under |path| except the directories/files in |excludes|.
  // |excluedes| can hold both absolute or relative paths, where absolute paths
  // are used as-is and relative paths are appended to |path| to make it
  // absolute. |callback| is invoked when the request is finished or canceled.
  void RequestFlush(const base::FilePath& path,
                    const std::vector<base::FilePath>& excludes,
                    const base::Closure& callback);

  // Set a callback for every file flush for test. Note the callback is
  // called on a blocking pool thread.
  using OnFlushCallback = base::Callback<void(const base::FilePath&)>;
  void set_on_flush_callback_for_test(
      const OnFlushCallback& on_flush_callback) {
    on_flush_callback_for_test_ = on_flush_callback;
  }

  void PauseForTest();
  void ResumeForTest();

 private:
  // Job for the flushing requests.
  class Job;

  // Starts the first job in |jobs_|.
  void ScheduleJob();

  // Invoked by a Job when it finishes.
  void OnJobDone(Job* job);

  // Not owned. Job manages its own life time.
  std::vector<Job*> jobs_;

  // A callback for testing to be invoked when a file is flushed.
  OnFlushCallback on_flush_callback_for_test_;

  bool paused_for_test_ = false;

  base::WeakPtrFactory<FileFlusher> weak_factory_;

  DISALLOW_COPY_AND_ASSIGN(FileFlusher);
};

}  // namespace chromeos

#endif  // CHROME_BROWSER_CHROMEOS_BASE_FILE_FLUSHER_H_