1// Copyright 2013 The Flutter Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef FLUTTER_FML_TASK_RUNNER_H_
6#define FLUTTER_FML_TASK_RUNNER_H_
7
8#include "flutter/fml/closure.h"
9#include "flutter/fml/macros.h"
10#include "flutter/fml/memory/ref_counted.h"
11#include "flutter/fml/memory/ref_ptr.h"
12#include "flutter/fml/message_loop_task_queues.h"
13#include "flutter/fml/time/time_point.h"
14
15namespace fml {
16
17class MessageLoopImpl;
18
19/// An interface over the ability to schedule tasks on a \p TaskRunner.
20class BasicTaskRunner {
21 public:
22 /// Schedules \p task to be executed on the TaskRunner's associated event
23 /// loop.
24 virtual void PostTask(const fml::closure& task) = 0;
25};
26
27/// The object for scheduling tasks on a \p fml::MessageLoop.
28///
29/// Typically there is one \p TaskRunner associated with each thread. When one
30/// wants to execute an operation on that thread they post a task to the
31/// TaskRunner.
32///
33/// \see fml::MessageLoop
34class TaskRunner : public fml::RefCountedThreadSafe<TaskRunner>,
35 public BasicTaskRunner {
36 public:
37 virtual ~TaskRunner();
38
39 virtual void PostTask(const fml::closure& task) override;
40
41 virtual void PostTaskForTime(const fml::closure& task,
42 fml::TimePoint target_time);
43
44 /// Schedules a task to be run on the MessageLoop after the time \p delay has
45 /// passed.
46 /// \note There is latency between when the task is schedule and actually
47 /// executed so that the actual execution time is: now + delay +
48 /// message_loop_latency, where message_loop_latency is undefined and could be
49 /// tens of milliseconds.
50 virtual void PostDelayedTask(const fml::closure& task, fml::TimeDelta delay);
51
52 /// Returns \p true when the current executing thread's TaskRunner matches
53 /// this instance.
54 virtual bool RunsTasksOnCurrentThread();
55
56 /// Returns the unique identifier associated with the TaskRunner.
57 /// \see fml::MessageLoopTaskQueues
58 virtual TaskQueueId GetTaskQueueId();
59
60 /// Executes the \p task directly if the TaskRunner \p runner is the
61 /// TaskRunner associated with the current executing thread.
62 static void RunNowOrPostTask(const fml::RefPtr<fml::TaskRunner>& runner,
63 const fml::closure& task);
64
65 protected:
66 explicit TaskRunner(fml::RefPtr<MessageLoopImpl> loop);
67
68 private:
69 fml::RefPtr<MessageLoopImpl> loop_;
70
71 FML_FRIEND_MAKE_REF_COUNTED(TaskRunner);
72 FML_FRIEND_REF_COUNTED_THREAD_SAFE(TaskRunner);
73 FML_DISALLOW_COPY_AND_ASSIGN(TaskRunner);
74};
75
76} // namespace fml
77
78#endif // FLUTTER_FML_TASK_RUNNER_H_
79

source code of flutter_engine/flutter/fml/task_runner.h