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| 1 // Copyright (c) 2009 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 JINGLE_NOTIFIER_BASE_SIGNAL_THREAD_TASK_H_ |
| 6 #define JINGLE_NOTIFIER_BASE_SIGNAL_THREAD_TASK_H_ |
| 7 |
| 8 #include "base/logging.h" |
| 9 #include "talk/base/common.h" |
| 10 #include "talk/base/signalthread.h" |
| 11 #include "talk/base/sigslot.h" |
| 12 #include "talk/base/task.h" |
| 13 |
| 14 namespace notifier { |
| 15 |
| 16 template<class T> |
| 17 class SignalThreadTask : public talk_base::Task, |
| 18 public sigslot::has_slots<> { |
| 19 public: |
| 20 // Takes ownership of signal_thread. |
| 21 SignalThreadTask(talk_base::Task* task_parent, T** signal_thread) |
| 22 : talk_base::Task(task_parent), |
| 23 signal_thread_(NULL), |
| 24 finished_(false) { |
| 25 SetSignalThread(signal_thread); |
| 26 } |
| 27 |
| 28 virtual ~SignalThreadTask() { |
| 29 ClearSignalThread(); |
| 30 } |
| 31 |
| 32 virtual void Stop() { |
| 33 Task::Stop(); |
| 34 ClearSignalThread(); |
| 35 } |
| 36 |
| 37 virtual int ProcessStart() { |
| 38 DCHECK_EQ(GetState(), talk_base::Task::STATE_START); |
| 39 signal_thread_->SignalWorkDone.connect( |
| 40 this, |
| 41 &SignalThreadTask<T>::OnWorkDone); |
| 42 signal_thread_->Start(); |
| 43 return talk_base::Task::STATE_RESPONSE; |
| 44 } |
| 45 |
| 46 int ProcessResponse() { |
| 47 if (!finished_) { |
| 48 return talk_base::Task::STATE_BLOCKED; |
| 49 } |
| 50 SignalWorkDone(signal_thread_); |
| 51 ClearSignalThread(); |
| 52 return talk_base::Task::STATE_DONE; |
| 53 } |
| 54 |
| 55 sigslot::signal1<T*> SignalWorkDone; |
| 56 |
| 57 private: |
| 58 // Takes ownership of signal_thread. |
| 59 void SetSignalThread(T** signal_thread) { |
| 60 DCHECK(!signal_thread_); |
| 61 DCHECK(signal_thread); |
| 62 DCHECK(*signal_thread); |
| 63 // No one should be listening to the signal thread for work done. |
| 64 // They should be using this class instead. Unfortunately, we |
| 65 // can't verify this. |
| 66 |
| 67 signal_thread_ = *signal_thread; |
| 68 |
| 69 // Helps callers not to use signal thread after this point since this class |
| 70 // has taken ownership (and avoid the error of doing |
| 71 // signal_thread->Start()). |
| 72 *signal_thread = NULL; |
| 73 } |
| 74 |
| 75 void OnWorkDone(talk_base::SignalThread* signal_thread) { |
| 76 DCHECK_EQ(signal_thread, signal_thread_); |
| 77 finished_ = true; |
| 78 Wake(); |
| 79 } |
| 80 |
| 81 void ClearSignalThread() { |
| 82 if (signal_thread_) { |
| 83 // Don't wait on the thread destruction, or we may deadlock. |
| 84 signal_thread_->Destroy(false); |
| 85 signal_thread_ = NULL; |
| 86 } |
| 87 } |
| 88 |
| 89 T* signal_thread_; |
| 90 bool finished_; |
| 91 DISALLOW_COPY_AND_ASSIGN(SignalThreadTask); |
| 92 }; |
| 93 |
| 94 } // namespace notifier |
| 95 |
| 96 #endif // JINGLE_NOTIFIER_BASE_SIGNAL_THREAD_TASK_H_ |
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