1 | // Copyright 2017 the V8 project 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 V8_LIBPLATFORM_DEFAULT_FOREGROUND_TASK_RUNNER_H_ |
6 | #define V8_LIBPLATFORM_DEFAULT_FOREGROUND_TASK_RUNNER_H_ |
7 | |
8 | #include <queue> |
9 | |
10 | #include "include/libplatform/libplatform.h" |
11 | #include "include/v8-platform.h" |
12 | #include "src/base/platform/condition-variable.h" |
13 | #include "src/base/platform/mutex.h" |
14 | |
15 | namespace v8 { |
16 | namespace platform { |
17 | |
18 | class V8_PLATFORM_EXPORT DefaultForegroundTaskRunner |
19 | : public NON_EXPORTED_BASE(TaskRunner) { |
20 | public: |
21 | using TimeFunction = double (*)(); |
22 | |
23 | DefaultForegroundTaskRunner(IdleTaskSupport idle_task_support, |
24 | TimeFunction time_function); |
25 | |
26 | void Terminate(); |
27 | |
28 | std::unique_ptr<Task> PopTaskFromQueue(MessageLoopBehavior wait_for_work); |
29 | |
30 | std::unique_ptr<IdleTask> PopTaskFromIdleQueue(); |
31 | |
32 | void WaitForTaskLocked(const base::MutexGuard&); |
33 | |
34 | double MonotonicallyIncreasingTime(); |
35 | |
36 | // v8::TaskRunner implementation. |
37 | void PostTask(std::unique_ptr<Task> task) override; |
38 | |
39 | void PostDelayedTask(std::unique_ptr<Task> task, |
40 | double delay_in_seconds) override; |
41 | |
42 | void PostIdleTask(std::unique_ptr<IdleTask> task) override; |
43 | |
44 | bool IdleTasksEnabled() override; |
45 | |
46 | private: |
47 | // The same as PostTask, but the lock is already held by the caller. The |
48 | // {guard} parameter should make sure that the caller is holding the lock. |
49 | void PostTaskLocked(std::unique_ptr<Task> task, const base::MutexGuard&); |
50 | |
51 | // A caller of this function has to hold {lock_}. The {guard} parameter should |
52 | // make sure that the caller is holding the lock. |
53 | std::unique_ptr<Task> PopTaskFromDelayedQueueLocked(const base::MutexGuard&); |
54 | |
55 | bool terminated_ = false; |
56 | base::Mutex lock_; |
57 | base::ConditionVariable event_loop_control_; |
58 | std::queue<std::unique_ptr<Task>> task_queue_; |
59 | IdleTaskSupport idle_task_support_; |
60 | std::queue<std::unique_ptr<IdleTask>> idle_task_queue_; |
61 | |
62 | // Some helper constructs for the {delayed_task_queue_}. |
63 | using DelayedEntry = std::pair<double, std::unique_ptr<Task>>; |
64 | // Define a comparison operator for the delayed_task_queue_ to make sure |
65 | // that the unique_ptr in the DelayedEntry is not accessed in the priority |
66 | // queue. This is necessary because we have to reset the unique_ptr when we |
67 | // remove a DelayedEntry from the priority queue. |
68 | struct DelayedEntryCompare { |
69 | bool operator()(const DelayedEntry& left, const DelayedEntry& right) const { |
70 | return left.first > right.first; |
71 | } |
72 | }; |
73 | std::priority_queue<DelayedEntry, std::vector<DelayedEntry>, |
74 | DelayedEntryCompare> |
75 | delayed_task_queue_; |
76 | |
77 | TimeFunction time_function_; |
78 | }; |
79 | |
80 | } // namespace platform |
81 | } // namespace v8 |
82 | #endif // V8_LIBPLATFORM_DEFAULT_FOREGROUND_TASK_RUNNER_H_ |
83 |