| // Copyright 2018 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 BASE_TASK_SEQUENCE_MANAGER_SEQUENCED_TASK_SOURCE_H_ |
| #define BASE_TASK_SEQUENCE_MANAGER_SEQUENCED_TASK_SOURCE_H_ |
| |
| #include "base/optional.h" |
| #include "base/pending_task.h" |
| #include "base/task/sequence_manager/lazy_now.h" |
| #include "base/task/sequence_manager/tasks.h" |
| |
| namespace base { |
| namespace sequence_manager { |
| namespace internal { |
| |
| // Interface to pass tasks to ThreadController. |
| class SequencedTaskSource { |
| public: |
| virtual ~SequencedTaskSource() = default; |
| |
| // Returns the next task to run from this source or nullptr if |
| // there're no more tasks ready to run. If a task is returned, |
| // DidRunTask() must be invoked before the next call to SelectNextTask(). |
| virtual Task* SelectNextTask() = 0; |
| |
| // Notifies this source that the task previously obtained |
| // from SelectNextTask() has been completed. |
| virtual void DidRunTask() = 0; |
| |
| // Returns the delay till the next task or TimeDelta::Max() |
| // if there are no tasks left. |
| virtual TimeDelta DelayTillNextTask(LazyNow* lazy_now) const = 0; |
| |
| // Return true if there are any pending tasks in the task source which require |
| // high resolution timing. |
| virtual bool HasPendingHighResolutionTasks() = 0; |
| |
| // Called when we have run out of immediate work. If more immediate work |
| // becomes available as a result of any processing done by this callback, |
| // return true to schedule a future DoWork. |
| virtual bool OnSystemIdle() = 0; |
| }; |
| |
| } // namespace internal |
| } // namespace sequence_manager |
| } // namespace base |
| |
| #endif // BASE_TASK_SEQUENCE_MANAGER_SEQUENCED_TASK_SOURCE_H_ |