1 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef NET_BASE_COMPLETION_CALLBACK_H__ 6 #define NET_BASE_COMPLETION_CALLBACK_H__ 7 8 #include "base/task.h" 9 10 namespace net { 11 12 // A callback specialization that takes a single int parameter. Usually this 13 // is used to report a byte count or network error code. 14 typedef Callback1<int>::Type CompletionCallback; 15 16 // Used to implement a CompletionCallback. 17 template <class T> 18 class CompletionCallbackImpl : 19 public CallbackImpl< T, void (T::*)(int), Tuple1<int> > { 20 public: 21 CompletionCallbackImpl(T* obj, void (T::* meth)(int)) 22 : CallbackImpl< T, void (T::*)(int), 23 Tuple1<int> >::CallbackImpl(obj, meth) { 24 } 25 }; 26 27 // CancelableCompletionCallback is used for completion callbacks 28 // which may outlive the target for the method dispatch. In such a case, the 29 // provider of the callback calls Cancel() to mark the callback as 30 // "canceled". When the canceled callback is eventually run it does nothing 31 // other than to decrement the refcount to 0 and free the memory. 32 template <class T> 33 class CancelableCompletionCallback : 34 public CompletionCallbackImpl<T>, 35 public base::RefCounted<CancelableCompletionCallback<T> > { 36 public: 37 CancelableCompletionCallback(T* obj, void (T::* meth)(int)) 38 : CompletionCallbackImpl<T>(obj, meth), is_canceled_(false) { 39 } 40 41 void Cancel() { 42 is_canceled_ = true; 43 } 44 45 virtual void RunWithParams(const Tuple1<int>& params) { 46 if (is_canceled_) { 47 base::RefCounted<CancelableCompletionCallback<T> >::Release(); 48 } else { 49 CompletionCallbackImpl<T>::RunWithParams(params); 50 } 51 } 52 53 private: 54 bool is_canceled_; 55 }; 56 57 } // namespace net 58 59 #endif // NET_BASE_COMPLETION_CALLBACK_H__ 60
