1 /* 2 * Copyright 2014 The WebRTC Project Authors. All rights reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef WEBRTC_BASE_ASYNCINVOKER_INL_H_ 12 #define WEBRTC_BASE_ASYNCINVOKER_INL_H_ 13 14 #include "webrtc/base/bind.h" 15 #include "webrtc/base/callback.h" 16 #include "webrtc/base/criticalsection.h" 17 #include "webrtc/base/messagehandler.h" 18 #include "webrtc/base/refcount.h" 19 #include "webrtc/base/scoped_ref_ptr.h" 20 #include "webrtc/base/sigslot.h" 21 #include "webrtc/base/thread.h" 22 23 namespace rtc { 24 25 class AsyncInvoker; 26 27 // Helper class for AsyncInvoker. Runs a task and triggers a callback 28 // on the calling thread if necessary. Instances are ref-counted so their 29 // lifetime can be independent of AsyncInvoker. 30 class AsyncClosure : public RefCountInterface { 31 public: ~AsyncClosure()32 virtual ~AsyncClosure() {} 33 // Runs the asynchronous task, and triggers a callback to the calling 34 // thread if needed. Should be called from the target thread. 35 virtual void Execute() = 0; 36 }; 37 38 // Simple closure that doesn't trigger a callback for the calling thread. 39 template <class FunctorT> 40 class FireAndForgetAsyncClosure : public AsyncClosure { 41 public: FireAndForgetAsyncClosure(const FunctorT & functor)42 explicit FireAndForgetAsyncClosure(const FunctorT& functor) 43 : functor_(functor) {} Execute()44 virtual void Execute() { 45 functor_(); 46 } 47 private: 48 FunctorT functor_; 49 }; 50 51 // Base class for closures that may trigger a callback for the calling thread. 52 // Listens for the "destroyed" signals from the calling thread and the invoker, 53 // and cancels the callback to the calling thread if either is destroyed. 54 class NotifyingAsyncClosureBase : public AsyncClosure, 55 public sigslot::has_slots<> { 56 public: ~NotifyingAsyncClosureBase()57 virtual ~NotifyingAsyncClosureBase() { disconnect_all(); } 58 59 protected: 60 NotifyingAsyncClosureBase(AsyncInvoker* invoker, Thread* calling_thread); 61 void TriggerCallback(); SetCallback(const Callback0<void> & callback)62 void SetCallback(const Callback0<void>& callback) { 63 CritScope cs(&crit_); 64 callback_ = callback; 65 } CallbackCanceled()66 bool CallbackCanceled() const { return calling_thread_ == NULL; } 67 68 private: 69 Callback0<void> callback_; 70 CriticalSection crit_; 71 AsyncInvoker* invoker_; 72 Thread* calling_thread_; 73 74 void CancelCallback(); 75 }; 76 77 // Closures that have a non-void return value and require a callback. 78 template <class ReturnT, class FunctorT, class HostT> 79 class NotifyingAsyncClosure : public NotifyingAsyncClosureBase { 80 public: NotifyingAsyncClosure(AsyncInvoker * invoker,Thread * calling_thread,const FunctorT & functor,void (HostT::* callback)(ReturnT),HostT * callback_host)81 NotifyingAsyncClosure(AsyncInvoker* invoker, 82 Thread* calling_thread, 83 const FunctorT& functor, 84 void (HostT::*callback)(ReturnT), 85 HostT* callback_host) 86 : NotifyingAsyncClosureBase(invoker, calling_thread), 87 functor_(functor), 88 callback_(callback), 89 callback_host_(callback_host) {} Execute()90 virtual void Execute() { 91 ReturnT result = functor_(); 92 if (!CallbackCanceled()) { 93 SetCallback(Callback0<void>(Bind(callback_, callback_host_, result))); 94 TriggerCallback(); 95 } 96 } 97 98 private: 99 FunctorT functor_; 100 void (HostT::*callback_)(ReturnT); 101 HostT* callback_host_; 102 }; 103 104 // Closures that have a void return value and require a callback. 105 template <class FunctorT, class HostT> 106 class NotifyingAsyncClosure<void, FunctorT, HostT> 107 : public NotifyingAsyncClosureBase { 108 public: NotifyingAsyncClosure(AsyncInvoker * invoker,Thread * calling_thread,const FunctorT & functor,void (HostT::* callback)(),HostT * callback_host)109 NotifyingAsyncClosure(AsyncInvoker* invoker, 110 Thread* calling_thread, 111 const FunctorT& functor, 112 void (HostT::*callback)(), 113 HostT* callback_host) 114 : NotifyingAsyncClosureBase(invoker, calling_thread), 115 functor_(functor) { 116 SetCallback(Callback0<void>(Bind(callback, callback_host))); 117 } Execute()118 virtual void Execute() { 119 functor_(); 120 TriggerCallback(); 121 } 122 123 private: 124 FunctorT functor_; 125 }; 126 127 } // namespace rtc 128 129 #endif // WEBRTC_BASE_ASYNCINVOKER_INL_H_ 130