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// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_DOWNLOAD_PUBLIC_TASK_TASK_MANAGER_IMPL_H_
#define COMPONENTS_DOWNLOAD_PUBLIC_TASK_TASK_MANAGER_IMPL_H_
#include <stdint.h>
#include <map>
#include "base/component_export.h"
#include "components/download/public/task/task_manager.h"
#include "components/download/public/task/task_scheduler.h"
namespace download {
using TaskFinishedCallback = base::OnceCallback<void(bool)>;
// A class to manage the calls made to the TaskScheduler, that abstracts away
// the details of the TaskScheduler from the calling code. The tasks can run
// independently of each other as long as they have different |task_type|.
// Scheduling another task of same |task_type| before the task is started will
// overwrite the params of the scheduled task.
class COMPONENT_EXPORT(COMPONENTS_DOWNLOAD_PUBLIC_TASK) TaskManagerImpl
: public TaskManager {
public:
explicit TaskManagerImpl(std::unique_ptr<TaskScheduler> task_scheduler);
TaskManagerImpl(const TaskManagerImpl&) = delete;
TaskManagerImpl& operator=(const TaskManagerImpl&) = delete;
~TaskManagerImpl() override;
// Called to schedule a new task. Overwrites the params if a task of the same
// type is already scheduled. If the task is currently running, it will cache
// the params and schedule the task after the completion/stopping of the
// current task.
void ScheduleTask(DownloadTaskType task_type,
const TaskParams& params) override;
// Called to unschedule a scheduled task of the given type if it is not yet
// started. Doesn't cancel the currently running task.
void UnscheduleTask(DownloadTaskType task_type) override;
// Called when the system starts a scheduled task. The callback will be cached
// by the class and run after receiving a call to NotifyTaskFinished().
void OnStartScheduledTask(DownloadTaskType task_type,
TaskFinishedCallback callback) override;
// Called when the system decides to stop an already running task.
void OnStopScheduledTask(DownloadTaskType task_type) override;
// Should be called once the task is complete. The callback passed through
// OnStartScheduledTask() will be run in order to notify that the task is done
// and the system should reschedule the task with the original params if
// |needs_reschedule| is true. If there are pending params for a new task, a
// new task will be scheduled immediately and reschedule logic will not be
// run.
void NotifyTaskFinished(DownloadTaskType task_type,
bool needs_reschedule) override;
private:
// Whether a task of the given type is already running.
bool IsRunningTask(DownloadTaskType task_type) const;
std::unique_ptr<TaskScheduler> task_scheduler_;
// Contains the params for the currently running task, which gets cleared
// after the task is completed or stopped.
std::map<DownloadTaskType, TaskParams> current_task_params_;
// Contains params for the task to be scheduled. If a task is currently
// running, the new task will be scheduled after the current task is finished
// or immediately if there is no task running right now. The params will move
// to current_task_params_ when the task is started.
std::map<DownloadTaskType, TaskParams> pending_task_params_;
// Contains the callbacks passed through the OnStartScheduledTask(). These
// will be cleared when the task is completed or stopped by the system.
std::map<DownloadTaskType, TaskFinishedCallback> task_finished_callbacks_;
};
} // namespace download
#endif // COMPONENTS_DOWNLOAD_PUBLIC_TASK_TASK_MANAGER_IMPL_H_
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