1// Copyright 2013 The Chromium 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 CONTENT_BROWSER_STARTUP_TASK_RUNNER_H_
6#define CONTENT_BROWSER_STARTUP_TASK_RUNNER_H_
7
8#include <list>
9
10#include "base/callback.h"
11#include "base/single_thread_task_runner.h"
12
13#include "build/build_config.h"
14
15#include "content/public/browser/browser_main_runner.h"
16
17namespace content {
18
19// A startup task is a void function returning the status on completion.
20// a status of > 0 indicates a failure, and that no further startup tasks should
21// be run.
22typedef base::Callback<int(void)> StartupTask;
23
24// This class runs startup tasks. The tasks are either run immediately inline,
25// or are queued one at a time on the UI thread's message loop. If the events
26// are queued, UI events that are received during startup will be acted upon
27// between startup tasks. The motivation for this is that, on targets where the
28// UI is already started, it allows us to keep the UI responsive during startup.
29//
30// Note that this differs from a SingleThreadedTaskRunner in that there may be
31// no opportunity to handle UI events between the tasks of a
32// SingleThreadedTaskRunner.
33
34class CONTENT_EXPORT StartupTaskRunner {
35
36 public:
37  // Constructor: Note that |startup_complete_callback| is optional. If it is
38  // not null it will be called once all the startup tasks have run.
39  StartupTaskRunner(base::Callback<void(int)> startup_complete_callback,
40                    scoped_refptr<base::SingleThreadTaskRunner> proxy);
41
42  ~StartupTaskRunner();
43
44  // Add a task to the queue of startup tasks to be run.
45  void AddTask(StartupTask& callback);
46
47  // Start running the tasks asynchronously.
48  void StartRunningTasksAsync();
49
50  // Run all tasks, or all remaining tasks, synchronously
51  void RunAllTasksNow();
52
53 private:
54  friend class base::RefCounted<StartupTaskRunner>;
55
56  std::list<StartupTask> task_list_;
57  void WrappedTask();
58
59  base::Callback<void(int)> startup_complete_callback_;
60  scoped_refptr<base::SingleThreadTaskRunner> proxy_;
61
62  DISALLOW_COPY_AND_ASSIGN(StartupTaskRunner);
63};
64
65}  // namespace content
66#endif  // CONTENT_BROWSER_STARTUP_TASK_RUNNER_H_
67