sergeyu@chromium.org | 70022fa | 2014-02-07 19:03:26 +0000 | [diff] [blame] | 1 | /* |
| 2 | * libjingle |
| 3 | * Copyright 2014 Google Inc. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions are met: |
| 7 | * |
| 8 | * 1. Redistributions of source code must retain the above copyright notice, |
| 9 | * this list of conditions and the following disclaimer. |
| 10 | * 2. Redistributions in binary form must reproduce the above copyright notice, |
| 11 | * this list of conditions and the following disclaimer in the documentation |
| 12 | * and/or other materials provided with the distribution. |
| 13 | * 3. The name of the author may not be used to endorse or promote products |
| 14 | * derived from this software without specific prior written permission. |
| 15 | * |
| 16 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED |
| 17 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF |
| 18 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO |
| 19 | * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 20 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| 21 | * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; |
| 22 | * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| 23 | * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
| 24 | * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
| 25 | * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 26 | */ |
| 27 | |
| 28 | #ifndef TALK_BASE_ASYNCINVOKER_H_ |
| 29 | #define TALK_BASE_ASYNCINVOKER_H_ |
| 30 | |
| 31 | #include "talk/base/asyncinvoker-inl.h" |
| 32 | #include "talk/base/bind.h" |
henrike@webrtc.org | 54caffd | 2014-02-14 23:38:45 +0000 | [diff] [blame] | 33 | #include "talk/base/sigslot.h" |
sergeyu@chromium.org | 70022fa | 2014-02-07 19:03:26 +0000 | [diff] [blame] | 34 | #include "talk/base/scopedptrcollection.h" |
| 35 | #include "talk/base/thread.h" |
| 36 | |
| 37 | namespace talk_base { |
| 38 | |
| 39 | // Invokes function objects (aka functors) asynchronously on a Thread, and |
| 40 | // owns the lifetime of calls (ie, when this object is destroyed, calls in |
| 41 | // flight are cancelled). AsyncInvoker can optionally execute a user-specified |
| 42 | // function when the asynchronous call is complete, or operates in |
| 43 | // fire-and-forget mode otherwise. |
| 44 | // |
| 45 | // AsyncInvoker does not own the thread it calls functors on. |
| 46 | // |
| 47 | // A note about async calls and object lifetimes: users should |
| 48 | // be mindful of object lifetimes when calling functions asynchronously and |
| 49 | // ensure objects used by the function _cannot_ be deleted between the |
| 50 | // invocation and execution of the functor. AsyncInvoker is designed to |
| 51 | // help: any calls in flight will be cancelled when the AsyncInvoker used to |
| 52 | // make the call is destructed, and any calls executing will be allowed to |
| 53 | // complete before AsyncInvoker destructs. |
| 54 | // |
| 55 | // The easiest way to ensure lifetimes are handled correctly is to create a |
| 56 | // class that owns the Thread and AsyncInvoker objects, and then call its |
| 57 | // methods asynchronously as needed. |
| 58 | // |
| 59 | // Example: |
| 60 | // class MyClass { |
| 61 | // public: |
| 62 | // void FireAsyncTaskWithResult(Thread* thread, int x) { |
| 63 | // // Specify a callback to get the result upon completion. |
| 64 | // invoker_.AsyncInvoke<int>( |
| 65 | // thread, Bind(&MyClass::AsyncTaskWithResult, this, x), |
| 66 | // &MyClass::OnTaskComplete, this); |
| 67 | // } |
| 68 | // void FireAnotherAsyncTask(Thread* thread) { |
| 69 | // // No callback specified means fire-and-forget. |
| 70 | // invoker_.AsyncInvoke<void>( |
| 71 | // thread, Bind(&MyClass::AnotherAsyncTask, this)); |
| 72 | // |
| 73 | // private: |
| 74 | // int AsyncTaskWithResult(int x) { |
| 75 | // // Some long running process... |
| 76 | // return x * x; |
| 77 | // } |
| 78 | // void AnotherAsyncTask() { |
| 79 | // // Some other long running process... |
| 80 | // } |
| 81 | // void OnTaskComplete(int result) { result_ = result; } |
| 82 | // |
| 83 | // AsyncInvoker invoker_; |
| 84 | // int result_; |
| 85 | // }; |
henrike@webrtc.org | 54caffd | 2014-02-14 23:38:45 +0000 | [diff] [blame] | 86 | class AsyncInvoker : public MessageHandler { |
sergeyu@chromium.org | 70022fa | 2014-02-07 19:03:26 +0000 | [diff] [blame] | 87 | public: |
henrike@webrtc.org | 54caffd | 2014-02-14 23:38:45 +0000 | [diff] [blame] | 88 | AsyncInvoker(); |
| 89 | virtual ~AsyncInvoker(); |
| 90 | |
sergeyu@chromium.org | 70022fa | 2014-02-07 19:03:26 +0000 | [diff] [blame] | 91 | // Call |functor| asynchronously on |thread|, with no callback upon |
| 92 | // completion. Returns immediately. |
| 93 | template <class ReturnT, class FunctorT> |
| 94 | void AsyncInvoke(Thread* thread, |
| 95 | const FunctorT& functor, |
| 96 | uint32 id = 0) { |
henrike@webrtc.org | 54caffd | 2014-02-14 23:38:45 +0000 | [diff] [blame] | 97 | AsyncClosure* closure = |
| 98 | new RefCountedObject<FireAndForgetAsyncClosure<FunctorT> >(functor); |
| 99 | DoInvoke(thread, closure, id); |
sergeyu@chromium.org | 70022fa | 2014-02-07 19:03:26 +0000 | [diff] [blame] | 100 | } |
| 101 | |
| 102 | // Call |functor| asynchronously on |thread|, calling |callback| when done. |
| 103 | template <class ReturnT, class FunctorT, class HostT> |
| 104 | void AsyncInvoke(Thread* thread, |
| 105 | const FunctorT& functor, |
| 106 | void (HostT::*callback)(ReturnT), |
| 107 | HostT* callback_host, |
| 108 | uint32 id = 0) { |
henrike@webrtc.org | 54caffd | 2014-02-14 23:38:45 +0000 | [diff] [blame] | 109 | AsyncClosure* closure = |
| 110 | new RefCountedObject<NotifyingAsyncClosure<ReturnT, FunctorT, HostT> >( |
| 111 | this, Thread::Current(), functor, callback, callback_host); |
| 112 | DoInvoke(thread, closure, id); |
sergeyu@chromium.org | 70022fa | 2014-02-07 19:03:26 +0000 | [diff] [blame] | 113 | } |
| 114 | |
| 115 | // Call |functor| asynchronously on |thread|, calling |callback| when done. |
| 116 | // Overloaded for void return. |
| 117 | template <class ReturnT, class FunctorT, class HostT> |
| 118 | void AsyncInvoke(Thread* thread, |
| 119 | const FunctorT& functor, |
| 120 | void (HostT::*callback)(), |
| 121 | HostT* callback_host, |
| 122 | uint32 id = 0) { |
henrike@webrtc.org | 54caffd | 2014-02-14 23:38:45 +0000 | [diff] [blame] | 123 | AsyncClosure* closure = |
| 124 | new RefCountedObject<NotifyingAsyncClosure<void, FunctorT, HostT> >( |
| 125 | this, Thread::Current(), functor, callback, callback_host); |
| 126 | DoInvoke(thread, closure, id); |
sergeyu@chromium.org | 70022fa | 2014-02-07 19:03:26 +0000 | [diff] [blame] | 127 | } |
| 128 | |
| 129 | // Synchronously execute on |thread| all outstanding calls we own |
| 130 | // that are pending on |thread|, and wait for calls to complete |
| 131 | // before returning. Optionally filter by message id. |
| 132 | // The destructor will not wait for outstanding calls, so if that |
| 133 | // behavior is desired, call Flush() before destroying this object. |
| 134 | void Flush(Thread* thread, uint32 id = MQID_ANY); |
| 135 | |
henrike@webrtc.org | 54caffd | 2014-02-14 23:38:45 +0000 | [diff] [blame] | 136 | // Signaled when this object is destructed. |
| 137 | sigslot::signal0<> SignalInvokerDestroyed; |
| 138 | |
sergeyu@chromium.org | 70022fa | 2014-02-07 19:03:26 +0000 | [diff] [blame] | 139 | private: |
henrike@webrtc.org | 54caffd | 2014-02-14 23:38:45 +0000 | [diff] [blame] | 140 | virtual void OnMessage(Message* msg); |
| 141 | void DoInvoke(Thread* thread, AsyncClosure* closure, uint32 id); |
sergeyu@chromium.org | 70022fa | 2014-02-07 19:03:26 +0000 | [diff] [blame] | 142 | |
henrike@webrtc.org | 54caffd | 2014-02-14 23:38:45 +0000 | [diff] [blame] | 143 | bool destroying_; |
sergeyu@chromium.org | 70022fa | 2014-02-07 19:03:26 +0000 | [diff] [blame] | 144 | |
henrike@webrtc.org | 54caffd | 2014-02-14 23:38:45 +0000 | [diff] [blame] | 145 | DISALLOW_COPY_AND_ASSIGN(AsyncInvoker); |
sergeyu@chromium.org | 70022fa | 2014-02-07 19:03:26 +0000 | [diff] [blame] | 146 | }; |
| 147 | |
| 148 | } // namespace talk_base |
| 149 | |
| 150 | |
| 151 | #endif // TALK_BASE_ASYNCINVOKER_H_ |