text: // 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.
  
  #include "components/offline_pages/task/task.h"
  
  #include <utility>
  
  #include "base/check_op.h"
  #include "base/logging.h"
  #include "components/offline_pages/task/task_queue.h"
  
  namespace offline_pages {
  
  Task::Task() = default;
  Task::~Task() {
    // This may happen when tearing-down the |TaskQueue|.
    DLOG_IF(WARNING,
            state_ == TaskState::kRunning || state_ == TaskState::kSuspended)
        << "Task being destroyed before completion";
  }
  
  void Task::Execute(base::OnceClosure complete_callback) {
    DCHECK_EQ(TaskState::kWaiting, state_);
  
    state_ = TaskState::kRunning;
    task_completion_callback_ = std::move(complete_callback);
    Run();
  }
  
  void Task::TaskComplete() {
    DCHECK(state_ == TaskState::kRunning || state_ == TaskState::kSuspended)
        << "Can't complete task in this state: " << static_cast<int>(state_);
  
    state_ = TaskState::kCompleted;
    if (!task_completion_callback_.is_null())
      std::move(task_completion_callback_).Run();
  }
  
  void Task::Suspend() {
    DCHECK_EQ(TaskState::kRunning, state_);
    DCHECK(task_queue_) << "Must be owned by a task queue to suspend.";
    state_ = TaskState::kSuspended;
    task_queue_->SuspendTask(this);
  }
  
  void Task::Resume(base::OnceClosure on_resume) {
    DCHECK_EQ(TaskState::kSuspended, state_);
    DCHECK(task_queue_) << "Must be owned by a task queue to resume.";
    task_queue_->ResumeTask(this, std::move(on_resume));
  }
  
  }  // namespace offline_pages
  