mirror of
https://github.com/flutter/flutter.git
synced 2026-02-20 02:29:02 +08:00
86 lines
2.6 KiB
C++
86 lines
2.6 KiB
C++
// Copyright 2013 The Flutter 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 FLUTTER_FML_TASK_SOURCE_H_
|
|
#define FLUTTER_FML_TASK_SOURCE_H_
|
|
|
|
#include "flutter/fml/delayed_task.h"
|
|
#include "flutter/fml/task_queue_id.h"
|
|
#include "flutter/fml/task_source_grade.h"
|
|
|
|
namespace fml {
|
|
|
|
class MessageLoopTaskQueues;
|
|
|
|
/**
|
|
* A Source of tasks for the `MessageLoopTaskQueues` task dispatcher. This is a
|
|
* wrapper around a primary and secondary task heap with the difference between
|
|
* them being that the secondary task heap can be paused and resumed by the task
|
|
* dispatcher. `TaskSourceGrade` determines what task heap the task is assigned
|
|
* to.
|
|
*
|
|
* Registering Tasks
|
|
* -----------------
|
|
* The task dispatcher associates a task source with each `TaskQueueID`. When
|
|
* the user of the task dispatcher registers a task, the task is in-turn
|
|
* registered with the `TaskSource` corresponding to the `TaskQueueID`.
|
|
*
|
|
* Processing Tasks
|
|
* ----------------
|
|
* Task dispatcher provides the event loop a way to acquire tasks to run via
|
|
* `GetNextTaskToRun`. Task dispatcher asks the underlying `TaskSource` for the
|
|
* next task.
|
|
*/
|
|
class TaskSource {
|
|
public:
|
|
struct TopTask {
|
|
TaskQueueId task_queue_id;
|
|
const DelayedTask& task;
|
|
};
|
|
|
|
/// Construts a TaskSource with the given `task_queue_id`.
|
|
explicit TaskSource(TaskQueueId task_queue_id);
|
|
|
|
~TaskSource();
|
|
|
|
/// Drops the pending tasks from both primary and secondary task heaps.
|
|
void ShutDown();
|
|
|
|
/// Adds a task to the corresponding task heap as dictated by the
|
|
/// `TaskSourceGrade` of the `DelayedTask`.
|
|
void RegisterTask(const DelayedTask& task);
|
|
|
|
/// Pops the task heap corresponding to the `TaskSourceGrade`.
|
|
void PopTask(TaskSourceGrade grade);
|
|
|
|
/// Returns the number of pending tasks. Excludes the tasks from the secondary
|
|
/// heap if it's paused.
|
|
size_t GetNumPendingTasks() const;
|
|
|
|
/// Returns true if `GetNumPendingTasks` is zero.
|
|
bool IsEmpty() const;
|
|
|
|
/// Returns the top task based on scheduled time, taking into account whether
|
|
/// the secondary heap has been paused or not.
|
|
TopTask Top() const;
|
|
|
|
/// Pause providing tasks from secondary task heap.
|
|
void PauseSecondary();
|
|
|
|
/// Resume providing tasks from secondary task heap.
|
|
void ResumeSecondary();
|
|
|
|
private:
|
|
const fml::TaskQueueId task_queue_id_;
|
|
fml::DelayedTaskQueue primary_task_queue_;
|
|
fml::DelayedTaskQueue secondary_task_queue_;
|
|
int secondary_pause_requests_ = 0;
|
|
|
|
FML_DISALLOW_COPY_ASSIGN_AND_MOVE(TaskSource);
|
|
};
|
|
|
|
} // namespace fml
|
|
|
|
#endif // FLUTTER_FML_TASK_SOURCE_H_
|