15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Copyright (c) 2012 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)// This file provides a macro ONLY for use in testing. 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// DO NOT USE IN PRODUCTION CODE. There are much better ways to wait. 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// This code is very helpful in testing multi-threaded code, without depending 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// on almost any primitives. This is especially helpful if you are testing 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// those primitive multi-threaded constructs. 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// We provide a simple one argument spin wait (for 1 second), and a generic 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// spin wait (for longer periods of time). 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#ifndef BASE_SYNCHRONIZATION_SPIN_WAIT_H_ 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#define BASE_SYNCHRONIZATION_SPIN_WAIT_H_ 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/threading/platform_thread.h" 19eb525c5499e34cc9c4b825d6d9e75bb07cc06aceBen Murdoch#include "base/time/time.h" 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Provide a macro that will wait no longer than 1 second for an asynchronous 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// change is the value of an expression. 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// A typical use would be: 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// SPIN_FOR_1_SECOND_OR_UNTIL_TRUE(0 == f(x)); 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// The expression will be evaluated repeatedly until it is true, or until 285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// the time (1 second) expires. 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Since tests generally have a 5 second watch dog timer, this spin loop is 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// typically used to get the padding needed on a given test platform to assure 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// that the test passes, even if load varies, and external events vary. 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#define SPIN_FOR_1_SECOND_OR_UNTIL_TRUE(expression) \ 345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) SPIN_FOR_TIMEDELTA_OR_UNTIL_TRUE(base::TimeDelta::FromSeconds(1), \ 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) (expression)) 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#define SPIN_FOR_TIMEDELTA_OR_UNTIL_TRUE(delta, expression) do { \ 385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::TimeTicks start = base::TimeTicks::Now(); \ 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) const base::TimeDelta kTimeout = delta; \ 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) while (!(expression)) { \ 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (kTimeout < base::TimeTicks::Now() - start) { \ 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) EXPECT_LE((base::TimeTicks::Now() - start).InMilliseconds(), \ 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) kTimeout.InMilliseconds()) << "Timed out"; \ 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) break; \ 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } \ 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(50)); \ 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } \ 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } while (0) 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#endif // BASE_SYNCHRONIZATION_SPIN_WAIT_H_ 51