mfbt/ReentrancyGuard.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 /* Small helper class for asserting uses of a class are non-reentrant. */
   8
   9 #ifndef mozilla_ReentrancyGuard_h
  10 #define mozilla_ReentrancyGuard_h
  11
  12 #include "mozilla/Assertions.h"
  13 #include "mozilla/Attributes.h"
  14 #include "mozilla/GuardObjects.h"
  15
  16 namespace mozilla {
  17
  18 /* Useful for implementing containers that assert non-reentrancy */
  19 class ReentrancyGuard
  20 {
  21   MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
  22 #ifdef DEBUG
  23   bool& mEntered;
  24 #endif
  25
  26 public:
  27   template<class T>
  28 #ifdef DEBUG
  29   ReentrancyGuard(T& aObj
  30                   MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
  31     : mEntered(aObj.mEntered)
  32 #else
  33   ReentrancyGuard(T&
  34                   MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
  35 #endif
  36   {
  37     MOZ_GUARD_OBJECT_NOTIFIER_INIT;
  38 #ifdef DEBUG
  39     MOZ_ASSERT(!mEntered);
  40     mEntered = true;
  41 #endif
  42   }
  43   ~ReentrancyGuard()
  44   {
  45 #ifdef DEBUG
  46     mEntered = false;
  47 #endif
  48   }
  49
  50 private:
  51   ReentrancyGuard(const ReentrancyGuard&) MOZ_DELETE;
  52   void operator=(const ReentrancyGuard&) MOZ_DELETE;
  53 };
  54
  55 } // namespace mozilla
  56
  57 #endif /* mozilla_ReentrancyGuard_h */