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1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #include "base/threading/post_task_and_reply_impl.h" | 5 #include "base/threading/post_task_and_reply_impl.h" |
6 | 6 |
7 #include "base/bind.h" | 7 #include "base/bind.h" |
8 #include "base/location.h" | 8 #include "base/location.h" |
9 #include "base/single_thread_task_runner.h" | 9 #include "base/single_thread_task_runner.h" |
10 #include "base/thread_task_runner_handle.h" | 10 #include "base/thread_task_runner_handle.h" |
11 | 11 |
12 namespace base { | 12 namespace base { |
13 | 13 |
14 namespace { | 14 namespace { |
15 | 15 |
16 // This relay class remembers the MessageLoop that it was created on, and | 16 // This relay class remembers the MessageLoop that it was created on, and |
17 // ensures that both the |task| and |reply| Closures are deleted on this same | 17 // ensures that both the |task| and |reply| Closures are deleted on this same |
18 // thread. Also, |task| is guaranteed to be deleted before |reply| is run or | 18 // thread. Also, |task| is guaranteed to be deleted before |reply| is run or |
19 // deleted. | 19 // deleted. |
20 // | 20 // |
21 // If this is not possible because the originating MessageLoop is no longer | 21 // If this is not possible because the originating MessageLoop is no longer |
22 // available, the the |task| and |reply| Closures are leaked. Leaking is | 22 // available, the the |task| and |reply| Closures are leaked. Leaking is |
23 // considered preferable to having a thread-safetey violations caused by | 23 // considered preferable to having a thread-safetey violations caused by |
24 // invoking the Closure destructor on the wrong thread. | 24 // invoking the Closure destructor on the wrong thread. |
25 class PostTaskAndReplyRelay { | 25 class PostTaskAndReplyRelay { |
26 public: | 26 public: |
27 PostTaskAndReplyRelay(const tracked_objects::Location& from_here, | 27 PostTaskAndReplyRelay(const tracked_objects::Location& from_here, |
28 const Closure& task, const Closure& reply) | 28 const Closure& task, |
| 29 const Closure& reply) |
29 : from_here_(from_here), | 30 : from_here_(from_here), |
30 origin_loop_(ThreadTaskRunnerHandle::Get()) { | 31 origin_task_runner_(ThreadTaskRunnerHandle::Get()) { |
31 task_ = task; | 32 task_ = task; |
32 reply_ = reply; | 33 reply_ = reply; |
33 } | 34 } |
34 | 35 |
35 ~PostTaskAndReplyRelay() { | 36 ~PostTaskAndReplyRelay() { |
36 DCHECK(origin_loop_->BelongsToCurrentThread()); | 37 DCHECK(origin_task_runner_->BelongsToCurrentThread()); |
37 task_.Reset(); | 38 task_.Reset(); |
38 reply_.Reset(); | 39 reply_.Reset(); |
39 } | 40 } |
40 | 41 |
41 void Run() { | 42 void Run() { |
42 task_.Run(); | 43 task_.Run(); |
43 origin_loop_->PostTask( | 44 origin_task_runner_->PostTask( |
44 from_here_, | 45 from_here_, Bind(&PostTaskAndReplyRelay::RunReplyAndSelfDestruct, |
45 Bind(&PostTaskAndReplyRelay::RunReplyAndSelfDestruct, | 46 base::Unretained(this))); |
46 base::Unretained(this))); | |
47 } | 47 } |
48 | 48 |
49 private: | 49 private: |
50 void RunReplyAndSelfDestruct() { | 50 void RunReplyAndSelfDestruct() { |
51 DCHECK(origin_loop_->BelongsToCurrentThread()); | 51 DCHECK(origin_task_runner_->BelongsToCurrentThread()); |
52 | 52 |
53 // Force |task_| to be released before |reply_| is to ensure that no one | 53 // Force |task_| to be released before |reply_| is to ensure that no one |
54 // accidentally depends on |task_| keeping one of its arguments alive while | 54 // accidentally depends on |task_| keeping one of its arguments alive while |
55 // |reply_| is executing. | 55 // |reply_| is executing. |
56 task_.Reset(); | 56 task_.Reset(); |
57 | 57 |
58 reply_.Run(); | 58 reply_.Run(); |
59 | 59 |
60 // Cue mission impossible theme. | 60 // Cue mission impossible theme. |
61 delete this; | 61 delete this; |
62 } | 62 } |
63 | 63 |
64 tracked_objects::Location from_here_; | 64 tracked_objects::Location from_here_; |
65 scoped_refptr<SingleThreadTaskRunner> origin_loop_; | 65 scoped_refptr<SingleThreadTaskRunner> origin_task_runner_; |
66 Closure reply_; | 66 Closure reply_; |
67 Closure task_; | 67 Closure task_; |
68 }; | 68 }; |
69 | 69 |
70 } // namespace | 70 } // namespace |
71 | 71 |
72 namespace internal { | 72 namespace internal { |
73 | 73 |
74 bool PostTaskAndReplyImpl::PostTaskAndReply( | 74 bool PostTaskAndReplyImpl::PostTaskAndReply( |
75 const tracked_objects::Location& from_here, | 75 const tracked_objects::Location& from_here, |
76 const Closure& task, | 76 const Closure& task, |
77 const Closure& reply) { | 77 const Closure& reply) { |
78 PostTaskAndReplyRelay* relay = | 78 PostTaskAndReplyRelay* relay = |
79 new PostTaskAndReplyRelay(from_here, task, reply); | 79 new PostTaskAndReplyRelay(from_here, task, reply); |
80 if (!PostTask(from_here, Bind(&PostTaskAndReplyRelay::Run, | 80 if (!PostTask(from_here, Bind(&PostTaskAndReplyRelay::Run, |
81 Unretained(relay)))) { | 81 Unretained(relay)))) { |
82 delete relay; | 82 delete relay; |
83 return false; | 83 return false; |
84 } | 84 } |
85 | 85 |
86 return true; | 86 return true; |
87 } | 87 } |
88 | 88 |
89 } // namespace internal | 89 } // namespace internal |
90 | 90 |
91 } // namespace base | 91 } // namespace base |
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