cancelable_callback.h revision 5821806d5e7f356e8fa4b058a389a808ea183019
15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Copyright (c) 2011 The Chromium Authors. All rights reserved. 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Use of this source code is governed by a BSD-style license that can be 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// found in the LICENSE file. 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 55821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// CancelableCallback is a wrapper around base::Callback that allows 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// cancellation of a callback. CancelableCallback takes a reference on the 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// wrapped callback until this object is destroyed or Reset()/Cancel() are 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// called. 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// NOTE: 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Calling CancellableCallback::Cancel() brings the object back to its natural, 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// default-constructed state, i.e., CancellableCallback::callback() will return 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// a null callback. 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// THREAD-SAFETY: 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// CancelableCallback objects must be created on, posted to, cancelled on, and 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// destroyed on the same thread. 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// EXAMPLE USAGE: 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// In the following example, the test is verifying that RunIntensiveTest() 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Quit()s the message loop within 4 seconds. The cancelable callback is posted 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// to the message loop, the intensive test runs, the message loop is run, 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// then the callback is cancelled. 285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// void TimeoutCallback(const std::string& timeout_message) { 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// FAIL() << timeout_message; 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// MessageLoop::current()->Quit(); 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// } 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// CancelableClosure timeout(base::Bind(&TimeoutCallback, "Test timed out.")); 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// MessageLoop::current()->PostDelayedTask(FROM_HERE, timeout.callback(), 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 4000) // 4 seconds to run. 375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// RunIntensiveTest(); 385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// MessageLoop::current()->Run(); 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// timeout.Cancel(); // Hopefully this is hit before the timeout callback runs. 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#ifndef BASE_CANCELABLE_CALLBACK_H_ 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#define BASE_CANCELABLE_CALLBACK_H_ 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/base_export.h" 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/bind.h" 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/callback.h" 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/callback_internal.h" 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/compiler_specific.h" 505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/logging.h" 515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/memory/weak_ptr.h" 525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)namespace base { 545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)template <typename Sig> 565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)class CancelableCallback; 575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)template <> 595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)class CancelableCallback<void(void)> { 605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) public: 615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) CancelableCallback() : ALLOW_THIS_IN_INITIALIZER_LIST(weak_factory_(this)) {} 625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // |callback| must not be null. 645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) explicit CancelableCallback(const base::Callback<void(void)>& callback) 655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) : ALLOW_THIS_IN_INITIALIZER_LIST(weak_factory_(this)), 665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) callback_(callback) { 675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(!callback.is_null()); 685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) InitializeForwarder(); 695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ~CancelableCallback() {} 725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 735821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Cancels and drops the reference to the wrapped callback. 745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Cancel() { 755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) weak_factory_.InvalidateWeakPtrs(); 765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) forwarder_.Reset(); 775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) callback_.Reset(); 785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Returns true if the wrapped callback has been cancelled. 815821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) bool IsCancelled() const { 825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return callback_.is_null(); 835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Sets |callback| as the closure that may be cancelled. |callback| may not 865821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // be null. Outstanding and any previously wrapped callbacks are cancelled. 875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Reset(const base::Callback<void(void)>& callback) { 885821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(!callback.is_null()); 895821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Outstanding tasks (e.g., posted to a message loop) must not be called. 915821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Cancel(); 925821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 935821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // |forwarder_| is no longer valid after Cancel(), so re-bind. 945821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) InitializeForwarder(); 955821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 965821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) callback_ = callback; 975821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 985821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 995821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Returns a callback that can be disabled by calling Cancel(). 1005821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) const base::Callback<void(void)>& callback() const { 1015821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return forwarder_; 1025821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1035821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1045821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) private: 1055821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Forward() { 1065821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) callback_.Run(); 1075821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1085821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1095821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Helper method to bind |forwarder_| using a weak pointer from 1105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // |weak_factory_|. 1115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void InitializeForwarder() { 1125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) forwarder_ = base::Bind(&CancelableCallback<void(void)>::Forward, 1135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) weak_factory_.GetWeakPtr()); 1145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Used to ensure Forward() is not run when this object is destroyed. 1175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::WeakPtrFactory<CancelableCallback<void(void)> > weak_factory_; 1185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // The wrapper closure. 1205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::Callback<void(void)> forwarder_; 1215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // The stored closure that may be cancelled. 1235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::Callback<void(void)> callback_; 1245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DISALLOW_COPY_AND_ASSIGN(CancelableCallback); 1265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)}; 1275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)template <typename A1> 1295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)class CancelableCallback<void(A1)> { 1305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) public: 1315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) CancelableCallback() : ALLOW_THIS_IN_INITIALIZER_LIST(weak_factory_(this)) {} 1325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // |callback| must not be null. 1345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) explicit CancelableCallback(const base::Callback<void(A1)>& callback) 1355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) : ALLOW_THIS_IN_INITIALIZER_LIST(weak_factory_(this)), 1365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) callback_(callback) { 1375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(!callback.is_null()); 1385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) InitializeForwarder(); 1395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ~CancelableCallback() {} 1425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Cancels and drops the reference to the wrapped callback. 1445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Cancel() { 1455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) weak_factory_.InvalidateWeakPtrs(); 1465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) forwarder_.Reset(); 1475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) callback_.Reset(); 1485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Returns true if the wrapped callback has been cancelled. 1515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) bool IsCancelled() const { 1525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return callback_.is_null(); 1535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Sets |callback| as the closure that may be cancelled. |callback| may not 1565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // be null. Outstanding and any previously wrapped callbacks are cancelled. 1575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Reset(const base::Callback<void(A1)>& callback) { 1585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(!callback.is_null()); 1595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Outstanding tasks (e.g., posted to a message loop) must not be called. 1615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Cancel(); 1625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // |forwarder_| is no longer valid after Cancel(), so re-bind. 1645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) InitializeForwarder(); 1655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) callback_ = callback; 1675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Returns a callback that can be disabled by calling Cancel(). 1705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) const base::Callback<void(A1)>& callback() const { 1715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return forwarder_; 1725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1735821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) private: 1755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Forward(A1 a1) const { 1765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) callback_.Run(a1); 1775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Helper method to bind |forwarder_| using a weak pointer from 1805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // |weak_factory_|. 1815821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void InitializeForwarder() { 1825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) forwarder_ = base::Bind(&CancelableCallback<void(A1)>::Forward, 1835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) weak_factory_.GetWeakPtr()); 1845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1865821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Used to ensure Forward() is not run when this object is destroyed. 1875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::WeakPtrFactory<CancelableCallback<void(A1)> > weak_factory_; 1885821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1895821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // The wrapper closure. 1905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::Callback<void(A1)> forwarder_; 1915821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1925821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // The stored closure that may be cancelled. 1935821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::Callback<void(A1)> callback_; 1945821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1955821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DISALLOW_COPY_AND_ASSIGN(CancelableCallback); 1965821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)}; 1975821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1985821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)typedef CancelableCallback<void(void)> CancelableClosure; 1995821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2005821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} // namespace base 2015821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2025821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#endif // BASE_CANCELABLE_CALLBACK_H_ 203