1// Copyright (c) 2012 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#include "base/threading/worker_pool.h"
6
7#include "base/bind.h"
8#include "base/compiler_specific.h"
9#include "base/debug/leak_annotations.h"
10#include "base/lazy_instance.h"
11#include "base/task_runner.h"
12#include "base/threading/post_task_and_reply_impl.h"
13#include "base/tracked_objects.h"
14
15namespace base {
16
17namespace {
18
19class PostTaskAndReplyWorkerPool : public internal::PostTaskAndReplyImpl {
20 public:
21  explicit PostTaskAndReplyWorkerPool(bool task_is_slow)
22      : task_is_slow_(task_is_slow) {
23  }
24
25 private:
26  virtual bool PostTask(const tracked_objects::Location& from_here,
27                        const Closure& task) OVERRIDE {
28    return WorkerPool::PostTask(from_here, task, task_is_slow_);
29  }
30
31  bool task_is_slow_;
32};
33
34// WorkerPoolTaskRunner ---------------------------------------------
35// A TaskRunner which posts tasks to a WorkerPool with a
36// fixed ShutdownBehavior.
37//
38// Note that this class is RefCountedThreadSafe (inherited from TaskRunner).
39class WorkerPoolTaskRunner : public TaskRunner {
40 public:
41  explicit WorkerPoolTaskRunner(bool tasks_are_slow);
42
43  // TaskRunner implementation
44  virtual bool PostDelayedTask(const tracked_objects::Location& from_here,
45                               const Closure& task,
46                               TimeDelta delay) OVERRIDE;
47  virtual bool RunsTasksOnCurrentThread() const OVERRIDE;
48
49 private:
50  virtual ~WorkerPoolTaskRunner();
51
52  // Helper function for posting a delayed task. Asserts that the delay is
53  // zero because non-zero delays are not supported.
54  bool PostDelayedTaskAssertZeroDelay(
55      const tracked_objects::Location& from_here,
56      const Closure& task,
57      base::TimeDelta delay);
58
59  const bool tasks_are_slow_;
60
61  DISALLOW_COPY_AND_ASSIGN(WorkerPoolTaskRunner);
62};
63
64WorkerPoolTaskRunner::WorkerPoolTaskRunner(bool tasks_are_slow)
65    : tasks_are_slow_(tasks_are_slow) {
66}
67
68WorkerPoolTaskRunner::~WorkerPoolTaskRunner() {
69}
70
71bool WorkerPoolTaskRunner::PostDelayedTask(
72    const tracked_objects::Location& from_here,
73    const Closure& task,
74    TimeDelta delay) {
75  return PostDelayedTaskAssertZeroDelay(from_here, task, delay);
76}
77
78bool WorkerPoolTaskRunner::RunsTasksOnCurrentThread() const {
79  return WorkerPool::RunsTasksOnCurrentThread();
80}
81
82bool WorkerPoolTaskRunner::PostDelayedTaskAssertZeroDelay(
83    const tracked_objects::Location& from_here,
84    const Closure& task,
85    base::TimeDelta delay) {
86  DCHECK_EQ(delay.InMillisecondsRoundedUp(), 0)
87      << "WorkerPoolTaskRunner does not support non-zero delays";
88  return WorkerPool::PostTask(from_here, task, tasks_are_slow_);
89}
90
91struct TaskRunnerHolder {
92  TaskRunnerHolder() {
93    taskrunners_[0] = new WorkerPoolTaskRunner(false);
94    taskrunners_[1] = new WorkerPoolTaskRunner(true);
95  }
96  scoped_refptr<TaskRunner> taskrunners_[2];
97};
98
99base::LazyInstance<TaskRunnerHolder>::Leaky
100    g_taskrunners = LAZY_INSTANCE_INITIALIZER;
101
102}  // namespace
103
104bool WorkerPool::PostTaskAndReply(const tracked_objects::Location& from_here,
105                                  const Closure& task,
106                                  const Closure& reply,
107                                  bool task_is_slow) {
108  // Do not report PostTaskAndReplyRelay leaks in tests. There's nothing we can
109  // do about them because WorkerPool doesn't have a flushing API.
110  // http://crbug.com/248513
111  // http://crbug.com/290897
112  // Note: this annotation does not cover tasks posted through a TaskRunner.
113  ANNOTATE_SCOPED_MEMORY_LEAK;
114  return PostTaskAndReplyWorkerPool(task_is_slow).PostTaskAndReply(
115      from_here, task, reply);
116}
117
118// static
119const scoped_refptr<TaskRunner>&
120WorkerPool::GetTaskRunner(bool tasks_are_slow) {
121  return g_taskrunners.Get().taskrunners_[tasks_are_slow];
122}
123
124}  // namespace base
125