51 lines
2.0 KiB
C
51 lines
2.0 KiB
C
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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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// This file provides a macro ONLY for use in testing.
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// DO NOT USE IN PRODUCTION CODE. There are much better ways to wait.
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// This code is very helpful in testing multi-threaded code, without depending
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// on almost any primitives. This is especially helpful if you are testing
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// those primitive multi-threaded constructs.
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// We provide a simple one argument spin wait (for 1 second), and a generic
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// spin wait (for longer periods of time).
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#ifndef BASE_SYNCHRONIZATION_SPIN_WAIT_H_
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#define BASE_SYNCHRONIZATION_SPIN_WAIT_H_
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#include "base/threading/platform_thread.h"
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#include "base/time/time.h"
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// Provide a macro that will wait no longer than 1 second for an asynchronous
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// change is the value of an expression.
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// A typical use would be:
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//
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// SPIN_FOR_1_SECOND_OR_UNTIL_TRUE(0 == f(x));
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//
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// The expression will be evaluated repeatedly until it is true, or until
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// the time (1 second) expires.
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// Since tests generally have a 5 second watch dog timer, this spin loop is
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// typically used to get the padding needed on a given test platform to assure
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// that the test passes, even if load varies, and external events vary.
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#define SPIN_FOR_1_SECOND_OR_UNTIL_TRUE(expression) \
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SPIN_FOR_TIMEDELTA_OR_UNTIL_TRUE(base::TimeDelta::FromSeconds(1), \
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(expression))
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#define SPIN_FOR_TIMEDELTA_OR_UNTIL_TRUE(delta, expression) do { \
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base::TimeTicks start = base::TimeTicks::Now(); \
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const base::TimeDelta kTimeout = delta; \
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while (!(expression)) { \
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if (kTimeout < base::TimeTicks::Now() - start) { \
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EXPECT_LE((base::TimeTicks::Now() - start).InMilliseconds(), \
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kTimeout.InMilliseconds()) << "Timed out"; \
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break; \
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} \
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base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(50)); \
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} \
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} while (0)
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#endif // BASE_SYNCHRONIZATION_SPIN_WAIT_H_
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