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 MOZ_RAII ReentrancyGuard {
  20   MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
  21 #ifdef DEBUG
  22   bool& mEntered;
  23 #endif
  24
  25  public:
  26   template <class T>
  27 #ifdef DEBUG
  28   explicit ReentrancyGuard(T& aObj MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
  29       : mEntered(aObj.mEntered)
  30 #else
  31   explicit ReentrancyGuard(T& MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
  32 #endif
  33   {
  34     MOZ_GUARD_OBJECT_NOTIFIER_INIT;
  35 #ifdef DEBUG
  36     MOZ_ASSERT(!mEntered);
  37     mEntered = true;
  38 #endif
  39   }
  40   ~ReentrancyGuard() {
  41 #ifdef DEBUG
  42     mEntered = false;
  43 #endif
  44   }
  45
  46  private:
  47   ReentrancyGuard(const ReentrancyGuard&) = delete;
  48   void operator=(const ReentrancyGuard&) = delete;
  49 };
  50
  51 }  // namespace mozilla
  52
  53 #endif /* mozilla_ReentrancyGuard_h */