mfbt/ChaosMode.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_ChaosMode_h
   8 #define mozilla_ChaosMode_h
   9
  10 #include <stdint.h>
  11 #include <stdlib.h>
  12
  13 namespace mozilla {
  14
  15 /**
  16  * When "chaos mode" is activated, code that makes implicitly nondeterministic
  17  * choices is encouraged to make random and extreme choices, to test more
  18  * code paths and uncover bugs.
  19  */
  20 class ChaosMode
  21 {
  22 public:
  23   static bool isActive()
  24   {
  25     // Flip this to true to activate chaos mode
  26     return false;
  27   }
  28
  29   /**
  30    * Returns a somewhat (but not uniformly) random uint32_t < aBound.
  31    * Not to be used for anything except ChaosMode, since it's not very random.
  32    */
  33   static uint32_t randomUint32LessThan(uint32_t aBound)
  34   {
  35     return uint32_t(rand()) % aBound;
  36   }
  37 };
  38
  39 } /* namespace mozilla */
  40
  41 #endif /* mozilla_ChaosMode_h */