gecko-dev/mfbt/ChaosMode.h

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_ChaosMode_h
#define mozilla_ChaosMode_h
#include "mozilla/EnumSet.h"
#include <stdint.h>
#include <stdlib.h>
namespace mozilla {
/**
* When "chaos mode" is activated, code that makes implicitly nondeterministic
* choices is encouraged to make random and extreme choices, to test more
* code paths and uncover bugs.
*/
class ChaosMode
{
public:
enum ChaosFeature {
None = 0x0,
// Altering thread scheduling.
ThreadScheduling = 0x1,
// Altering network request scheduling.
NetworkScheduling = 0x2,
// Altering timer scheduling.
TimerScheduling = 0x4,
// Read and write less-than-requested amounts.
IOAmounts = 0x8,
// Iterate over hash tables in random order.
HashTableIteration = 0x10,
Any = 0xffffffff,
};
private:
// Change this to any non-None value to activate ChaosMode.
static const ChaosFeature sChaosFeatures = None;
public:
static bool isActive(ChaosFeature aFeature)
{
return sChaosFeatures & aFeature;
}
/**
* Returns a somewhat (but not uniformly) random uint32_t < aBound.
* Not to be used for anything except ChaosMode, since it's not very random.
*/
static uint32_t randomUint32LessThan(uint32_t aBound)
{
return uint32_t(rand()) % aBound;
}
};
} /* namespace mozilla */
#endif /* mozilla_ChaosMode_h */