mfbt/ChaosMode.h
author Robert O'Callahan <robert@ocallahan.org>
Mon, 03 Mar 2014 18:12:17 +1300
changeset 189854 f656d2fd42644436d984504570af35e6d57bc5ec
child 205018 038794b1a5bc9886976d9eac1d626f7b31e027b3
permissions -rw-r--r--
Bug 955888. Part 1: Add ChaosMode.h base functionality. r=waldo

/* -*- 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 <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:
    static bool isActive()
    {
      // Flip this to true to activate chaos mode
      return false;
    }

    /**
     * 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 */