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: 32 // Runs the asynchronous task, and triggers a callback to the calling 33 // thread if needed. Should be called from the target thread. 34 virtual void Execute() = 0; 35 protected: ~AsyncClosure()36 ~AsyncClosure() override {} 37 }; 38 39 // Simple closure that doesn't trigger a callback for the calling thread. 40 template <class FunctorT> 41 class FireAndForgetAsyncClosure : public AsyncClosure { 42 public: FireAndForgetAsyncClosure(const FunctorT & functor)43 explicit FireAndForgetAsyncClosure(const FunctorT& functor) 44 : functor_(functor) {} Execute()45 virtual void Execute() { 46 functor_(); 47 } 48 private: 49 FunctorT functor_; 50 }; 51 52 // Base class for closures that may trigger a callback for the calling thread. 53 // Listens for the "destroyed" signals from the calling thread and the invoker, 54 // and cancels the callback to the calling thread if either is destroyed. 55 class NotifyingAsyncClosureBase : public AsyncClosure, 56 public sigslot::has_slots<> { 57 public: 58 ~NotifyingAsyncClosureBase() override; 59 60 protected: 61 NotifyingAsyncClosureBase(AsyncInvoker* invoker, Thread* calling_thread); 62 void TriggerCallback(); SetCallback(const Callback0<void> & callback)63 void SetCallback(const Callback0<void>& callback) { 64 CritScope cs(&crit_); 65 callback_ = callback; 66 } CallbackCanceled()67 bool CallbackCanceled() const { return calling_thread_ == NULL; } 68 69 private: 70 Callback0<void> callback_; 71 CriticalSection crit_; 72 AsyncInvoker* invoker_; 73 Thread* calling_thread_; 74 75 void CancelCallback(); 76 }; 77 78 // Closures that have a non-void return value and require a callback. 79 template <class ReturnT, class FunctorT, class HostT> 80 class NotifyingAsyncClosure : public NotifyingAsyncClosureBase { 81 public: NotifyingAsyncClosure(AsyncInvoker * invoker,Thread * calling_thread,const FunctorT & functor,void (HostT::* callback)(ReturnT),HostT * callback_host)82 NotifyingAsyncClosure(AsyncInvoker* invoker, 83 Thread* calling_thread, 84 const FunctorT& functor, 85 void (HostT::*callback)(ReturnT), 86 HostT* callback_host) 87 : NotifyingAsyncClosureBase(invoker, calling_thread), 88 functor_(functor), 89 callback_(callback), 90 callback_host_(callback_host) {} Execute()91 virtual void Execute() { 92 ReturnT result = functor_(); 93 if (!CallbackCanceled()) { 94 SetCallback(Callback0<void>(Bind(callback_, callback_host_, result))); 95 TriggerCallback(); 96 } 97 } 98 99 private: 100 FunctorT functor_; 101 void (HostT::*callback_)(ReturnT); 102 HostT* callback_host_; 103 }; 104 105 // Closures that have a void return value and require a callback. 106 template <class FunctorT, class HostT> 107 class NotifyingAsyncClosure<void, FunctorT, HostT> 108 : public NotifyingAsyncClosureBase { 109 public: NotifyingAsyncClosure(AsyncInvoker * invoker,Thread * calling_thread,const FunctorT & functor,void (HostT::* callback)(),HostT * callback_host)110 NotifyingAsyncClosure(AsyncInvoker* invoker, 111 Thread* calling_thread, 112 const FunctorT& functor, 113 void (HostT::*callback)(), 114 HostT* callback_host) 115 : NotifyingAsyncClosureBase(invoker, calling_thread), 116 functor_(functor) { 117 SetCallback(Callback0<void>(Bind(callback, callback_host))); 118 } Execute()119 virtual void Execute() { 120 functor_(); 121 TriggerCallback(); 122 } 123 124 private: 125 FunctorT functor_; 126 }; 127 128 } // namespace rtc 129 130 #endif // WEBRTC_BASE_ASYNCINVOKER_INL_H_ 131