blob: 36ae083f20a278bcfb73f7e358e2a407fa115f92 [file] [log] [blame]
// 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__