| /* |
| * libjingle |
| * Copyright 2014 Google Inc. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright notice, |
| * this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright notice, |
| * this list of conditions and the following disclaimer in the documentation |
| * and/or other materials provided with the distribution. |
| * 3. The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED |
| * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF |
| * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO |
| * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; |
| * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
| * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
| * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #ifndef TALK_BASE_ASYNCINVOKER_H_ |
| #define TALK_BASE_ASYNCINVOKER_H_ |
| |
| #include "talk/base/asyncinvoker-inl.h" |
| #include "talk/base/bind.h" |
| #include "talk/base/sigslot.h" |
| #include "talk/base/scopedptrcollection.h" |
| #include "talk/base/thread.h" |
| |
| namespace talk_base { |
| |
| // Invokes function objects (aka functors) asynchronously on a Thread, and |
| // owns the lifetime of calls (ie, when this object is destroyed, calls in |
| // flight are cancelled). AsyncInvoker can optionally execute a user-specified |
| // function when the asynchronous call is complete, or operates in |
| // fire-and-forget mode otherwise. |
| // |
| // AsyncInvoker does not own the thread it calls functors on. |
| // |
| // A note about async calls and object lifetimes: users should |
| // be mindful of object lifetimes when calling functions asynchronously and |
| // ensure objects used by the function _cannot_ be deleted between the |
| // invocation and execution of the functor. AsyncInvoker is designed to |
| // help: any calls in flight will be cancelled when the AsyncInvoker used to |
| // make the call is destructed, and any calls executing will be allowed to |
| // complete before AsyncInvoker destructs. |
| // |
| // The easiest way to ensure lifetimes are handled correctly is to create a |
| // class that owns the Thread and AsyncInvoker objects, and then call its |
| // methods asynchronously as needed. |
| // |
| // Example: |
| // class MyClass { |
| // public: |
| // void FireAsyncTaskWithResult(Thread* thread, int x) { |
| // // Specify a callback to get the result upon completion. |
| // invoker_.AsyncInvoke<int>( |
| // thread, Bind(&MyClass::AsyncTaskWithResult, this, x), |
| // &MyClass::OnTaskComplete, this); |
| // } |
| // void FireAnotherAsyncTask(Thread* thread) { |
| // // No callback specified means fire-and-forget. |
| // invoker_.AsyncInvoke<void>( |
| // thread, Bind(&MyClass::AnotherAsyncTask, this)); |
| // |
| // private: |
| // int AsyncTaskWithResult(int x) { |
| // // Some long running process... |
| // return x * x; |
| // } |
| // void AnotherAsyncTask() { |
| // // Some other long running process... |
| // } |
| // void OnTaskComplete(int result) { result_ = result; } |
| // |
| // AsyncInvoker invoker_; |
| // int result_; |
| // }; |
| class AsyncInvoker : public MessageHandler { |
| public: |
| AsyncInvoker(); |
| virtual ~AsyncInvoker(); |
| |
| // Call |functor| asynchronously on |thread|, with no callback upon |
| // completion. Returns immediately. |
| template <class ReturnT, class FunctorT> |
| void AsyncInvoke(Thread* thread, |
| const FunctorT& functor, |
| uint32 id = 0) { |
| AsyncClosure* closure = |
| new RefCountedObject<FireAndForgetAsyncClosure<FunctorT> >(functor); |
| DoInvoke(thread, closure, id); |
| } |
| |
| // Call |functor| asynchronously on |thread|, calling |callback| when done. |
| template <class ReturnT, class FunctorT, class HostT> |
| void AsyncInvoke(Thread* thread, |
| const FunctorT& functor, |
| void (HostT::*callback)(ReturnT), |
| HostT* callback_host, |
| uint32 id = 0) { |
| AsyncClosure* closure = |
| new RefCountedObject<NotifyingAsyncClosure<ReturnT, FunctorT, HostT> >( |
| this, Thread::Current(), functor, callback, callback_host); |
| DoInvoke(thread, closure, id); |
| } |
| |
| // Call |functor| asynchronously on |thread|, calling |callback| when done. |
| // Overloaded for void return. |
| template <class ReturnT, class FunctorT, class HostT> |
| void AsyncInvoke(Thread* thread, |
| const FunctorT& functor, |
| void (HostT::*callback)(), |
| HostT* callback_host, |
| uint32 id = 0) { |
| AsyncClosure* closure = |
| new RefCountedObject<NotifyingAsyncClosure<void, FunctorT, HostT> >( |
| this, Thread::Current(), functor, callback, callback_host); |
| DoInvoke(thread, closure, id); |
| } |
| |
| // Synchronously execute on |thread| all outstanding calls we own |
| // that are pending on |thread|, and wait for calls to complete |
| // before returning. Optionally filter by message id. |
| // The destructor will not wait for outstanding calls, so if that |
| // behavior is desired, call Flush() before destroying this object. |
| void Flush(Thread* thread, uint32 id = MQID_ANY); |
| |
| // Signaled when this object is destructed. |
| sigslot::signal0<> SignalInvokerDestroyed; |
| |
| private: |
| virtual void OnMessage(Message* msg); |
| void DoInvoke(Thread* thread, AsyncClosure* closure, uint32 id); |
| |
| bool destroying_; |
| |
| DISALLOW_COPY_AND_ASSIGN(AsyncInvoker); |
| }; |
| |
| } // namespace talk_base |
| |
| |
| #endif // TALK_BASE_ASYNCINVOKER_H_ |