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
  15 namespace mozilla {
  16
  17 /* Useful for implementing containers that assert non-reentrancy */
  18 class MOZ_RAII ReentrancyGuard {
  19 #ifdef DEBUG
  20   bool& mEntered;
  21 #endif
  22
  23  public:
  24   template <class T>
  25 #ifdef DEBUG
  26   explicit ReentrancyGuard(T& aObj)
  27       : mEntered(aObj.mEntered)
  28 #else
  29   explicit ReentrancyGuard(T&)
  30 #endif
  31   {
  32 #ifdef DEBUG
  33     MOZ_ASSERT(!mEntered);
  34     mEntered = true;
  35 #endif
  36   }
  37   ~ReentrancyGuard() {
  38 #ifdef DEBUG
  39     mEntered = false;
  40 #endif
  41   }
  42
  43  private:
  44   ReentrancyGuard(const ReentrancyGuard&) = delete;
  45   void operator=(const ReentrancyGuard&) = delete;
  46 };
  47
  48 }  // namespace mozilla
  49
  50 #endif /* mozilla_ReentrancyGuard_h */