/* * 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_INL_H_ #define TALK_BASE_ASYNCINVOKER_INL_H_ #include "talk/base/bind.h" #include "talk/base/callback.h" #include "talk/base/criticalsection.h" #include "talk/base/messagehandler.h" #include "talk/base/refcount.h" #include "talk/base/scoped_ref_ptr.h" #include "talk/base/sigslot.h" #include "talk/base/thread.h" namespace talk_base { class AsyncInvoker; // Helper class for AsyncInvoker. Runs a task and triggers a callback // on the calling thread if necessary. Instances are ref-counted so their // lifetime can be independent of AsyncInvoker. class AsyncClosure : public RefCountInterface { public: virtual ~AsyncClosure() {} // Runs the asynchronous task, and triggers a callback to the calling // thread if needed. Should be called from the target thread. virtual void Execute() = 0; }; // Simple closure that doesn't trigger a callback for the calling thread. template <class FunctorT> class FireAndForgetAsyncClosure : public AsyncClosure { public: explicit FireAndForgetAsyncClosure(const FunctorT& functor) : functor_(functor) {} virtual void Execute() { functor_(); } private: FunctorT functor_; }; // Base class for closures that may trigger a callback for the calling thread. // Listens for the "destroyed" signals from the calling thread and the invoker, // and cancels the callback to the calling thread if either is destroyed. class NotifyingAsyncClosureBase : public AsyncClosure, public sigslot::has_slots<> { public: virtual ~NotifyingAsyncClosureBase() { disconnect_all(); } protected: NotifyingAsyncClosureBase(AsyncInvoker* invoker, Thread* calling_thread); void TriggerCallback(); void SetCallback(const Callback0<void>& callback) { CritScope cs(&crit_); callback_ = callback; } bool CallbackCanceled() const { return calling_thread_ == NULL; } private: Callback0<void> callback_; CriticalSection crit_; AsyncInvoker* invoker_; Thread* calling_thread_; void CancelCallback(); }; // Closures that have a non-void return value and require a callback. template <class ReturnT, class FunctorT, class HostT> class NotifyingAsyncClosure : public NotifyingAsyncClosureBase { public: NotifyingAsyncClosure(AsyncInvoker* invoker, Thread* calling_thread, const FunctorT& functor, void (HostT::*callback)(ReturnT), HostT* callback_host) : NotifyingAsyncClosureBase(invoker, calling_thread), functor_(functor), callback_(callback), callback_host_(callback_host) {} virtual void Execute() { ReturnT result = functor_(); if (!CallbackCanceled()) { SetCallback(Callback0<void>(Bind(callback_, callback_host_, result))); TriggerCallback(); } } private: FunctorT functor_; void (HostT::*callback_)(ReturnT); HostT* callback_host_; }; // Closures that have a void return value and require a callback. template <class FunctorT, class HostT> class NotifyingAsyncClosure<void, FunctorT, HostT> : public NotifyingAsyncClosureBase { public: NotifyingAsyncClosure(AsyncInvoker* invoker, Thread* calling_thread, const FunctorT& functor, void (HostT::*callback)(), HostT* callback_host) : NotifyingAsyncClosureBase(invoker, calling_thread), functor_(functor) { SetCallback(Callback0<void>(Bind(callback, callback_host))); } virtual void Execute() { functor_(); TriggerCallback(); } private: FunctorT functor_; }; } // namespace talk_base #endif // TALK_BASE_ASYNCINVOKER_INL_H_