| // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // This file provides a macro ONLY for use in testing. |
| // DO NOT USE IN PRODUCTION CODE. There are much better ways to wait. |
| |
| // This code is very helpful in testing multi-threaded code, without depending |
| // on almost any primitives. This is especially helpful if you are testing |
| // those primitive multi-threaded constructs. |
| |
| // We provide a simple one argument spin wait (for 1 second), and a generic |
| // spin wait (for longer periods of time). |
| |
| #ifndef BASE_SPIN_WAIT_H__ |
| #define BASE_SPIN_WAIT_H__ |
| |
| #include "base/platform_thread.h" |
| #include "base/time.h" |
| |
| // Provide a macro that will wait no longer than 1 second for an asynchronous |
| // change is the value of an expression. |
| // A typical use would be: |
| // |
| // SPIN_FOR_1_SECOND_OR_UNTIL_TRUE(0 == f(x)); |
| // |
| // The expression will be evaluated repeatedly until it is true, or until |
| // the time (1 second) expires. |
| // Since tests generally have a 5 second watch dog timer, this spin loop is |
| // typically used to get the padding needed on a given test platform to assure |
| // that the test passes, even if load varies, and external events vary. |
| |
| #define SPIN_FOR_1_SECOND_OR_UNTIL_TRUE(expression) \ |
| SPIN_FOR_TIMEDELTA_OR_UNTIL_TRUE(base::TimeDelta::FromSeconds(1), \ |
| (expression)) |
| |
| #define SPIN_FOR_TIMEDELTA_OR_UNTIL_TRUE(delta, expression) do { \ |
| base::Time start = base::Time::Now(); \ |
| const base::TimeDelta kTimeout = delta; \ |
| while (!(expression)) { \ |
| if (kTimeout < base::Time::Now() - start) { \ |
| EXPECT_LE((base::Time::Now() - start).InMilliseconds(), \ |
| kTimeout.InMilliseconds()) << "Timed out"; \ |
| break; \ |
| } \ |
| PlatformThread::Sleep(50); \ |
| } \ |
| } while (0) |
| |
| #endif // BASE_SPIN_WAIT_H__ |