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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 "net/dns/serial_worker.h" | |
6 | |
7 #include "base/bind.h" | |
8 #include "base/location.h" | |
9 #include "base/message_loop/message_loop_proxy.h" | |
10 #include "base/threading/worker_pool.h" | |
11 | |
12 namespace net { | |
13 | |
14 SerialWorker::SerialWorker() | |
15 : message_loop_(base::MessageLoopProxy::current()), | |
16 state_(IDLE) {} | |
17 | |
18 SerialWorker::~SerialWorker() {} | |
19 | |
20 void SerialWorker::WorkNow() { | |
21 DCHECK(message_loop_->BelongsToCurrentThread()); | |
22 switch (state_) { | |
23 case IDLE: | |
24 if (!base::WorkerPool::PostTask(FROM_HERE, base::Bind( | |
25 &SerialWorker::DoWorkJob, this), false)) { | |
26 #if defined(OS_POSIX) | |
27 // See worker_pool_posix.cc. | |
28 NOTREACHED() << "WorkerPool::PostTask is not expected to fail on posix"; | |
29 #else | |
30 LOG(WARNING) << "Failed to WorkerPool::PostTask, will retry later"; | |
31 const int kWorkerPoolRetryDelayMs = 100; | |
32 message_loop_->PostDelayedTask( | |
33 FROM_HERE, | |
34 base::Bind(&SerialWorker::RetryWork, this), | |
35 base::TimeDelta::FromMilliseconds(kWorkerPoolRetryDelayMs)); | |
36 state_ = WAITING; | |
37 return; | |
38 #endif | |
39 } | |
40 state_ = WORKING; | |
41 return; | |
42 case WORKING: | |
43 // Remember to re-read after |DoRead| finishes. | |
44 state_ = PENDING; | |
45 return; | |
46 case CANCELLED: | |
47 case PENDING: | |
48 case WAITING: | |
49 return; | |
50 default: | |
51 NOTREACHED() << "Unexpected state " << state_; | |
52 } | |
53 } | |
54 | |
55 void SerialWorker::Cancel() { | |
56 DCHECK(message_loop_->BelongsToCurrentThread()); | |
57 state_ = CANCELLED; | |
58 } | |
59 | |
60 void SerialWorker::DoWorkJob() { | |
61 this->DoWork(); | |
62 // If this fails, the loop is gone, so there is no point retrying. | |
63 message_loop_->PostTask(FROM_HERE, base::Bind( | |
64 &SerialWorker::OnWorkJobFinished, this)); | |
65 } | |
66 | |
67 void SerialWorker::OnWorkJobFinished() { | |
68 DCHECK(message_loop_->BelongsToCurrentThread()); | |
69 switch (state_) { | |
70 case CANCELLED: | |
71 return; | |
72 case WORKING: | |
73 state_ = IDLE; | |
74 this->OnWorkFinished(); | |
75 return; | |
76 case PENDING: | |
77 state_ = IDLE; | |
78 WorkNow(); | |
79 return; | |
80 default: | |
81 NOTREACHED() << "Unexpected state " << state_; | |
82 } | |
83 } | |
84 | |
85 void SerialWorker::RetryWork() { | |
86 DCHECK(message_loop_->BelongsToCurrentThread()); | |
87 switch (state_) { | |
88 case CANCELLED: | |
89 return; | |
90 case WAITING: | |
91 state_ = IDLE; | |
92 WorkNow(); | |
93 return; | |
94 default: | |
95 NOTREACHED() << "Unexpected state " << state_; | |
96 } | |
97 } | |
98 | |
99 } // namespace net | |
100 | |
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