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       1             : /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
       2             :  * vim: set ts=8 sts=4 et sw=4 tw=99:
       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 js_RefCounted_h
       8             : #define js_RefCounted_h
       9             : 
      10             : #include "mozilla/Atomics.h"
      11             : #include "mozilla/RefCountType.h"
      12             : 
      13             : #include "js/Utility.h"
      14             : 
      15             : // These types implement the same interface as mozilla::(Atomic)RefCounted and
      16             : // must be used instead of mozilla::(Atomic)RefCounted for everything in
      17             : // SpiderMonkey. There are two reasons:
      18             : //  - Release() needs to call js_delete, not delete
      19             : //  - SpiderMonkey does not have MOZILLA_INTERNAL_API defined which can lead
      20             : //    to ODR violations that show up as spurious leak reports when ref-counted
      21             : //    types are allocated by SpiderMonkey and released by Gecko (or vice versa).
      22             : 
      23             : namespace js {
      24             : 
      25             : template <typename T>
      26             : class RefCounted
      27             : {
      28             :     static const MozRefCountType DEAD = 0xffffdead;
      29             : 
      30             :   protected:
      31           0 :     RefCounted() : mRefCnt(0) {}
      32           0 :     ~RefCounted() { MOZ_ASSERT(mRefCnt == DEAD); }
      33             : 
      34             :   public:
      35           0 :     void AddRef() const
      36             :     {
      37           0 :         MOZ_ASSERT(int32_t(mRefCnt) >= 0);
      38           0 :         ++mRefCnt;
      39           0 :     }
      40             : 
      41           0 :     void Release() const
      42             :     {
      43           0 :       MOZ_ASSERT(int32_t(mRefCnt) > 0);
      44           0 :       MozRefCountType cnt = --mRefCnt;
      45           0 :       if (0 == cnt) {
      46             : #ifdef DEBUG
      47           0 :           mRefCnt = DEAD;
      48             : #endif
      49           0 :           js_delete(const_cast<T*>(static_cast<const T*>(this)));
      50             :       }
      51           0 :     }
      52             : 
      53             :   private:
      54             :     mutable MozRefCountType mRefCnt;
      55             : };
      56             : 
      57             : template <typename T>
      58             : class AtomicRefCounted
      59             : {
      60             :     static const MozRefCountType DEAD = 0xffffdead;
      61             : 
      62             :   protected:
      63           0 :     AtomicRefCounted() : mRefCnt(0) {}
      64           0 :     ~AtomicRefCounted() { MOZ_ASSERT(mRefCnt == DEAD); }
      65             : 
      66             :   public:
      67           0 :     void AddRef() const
      68             :     {
      69           0 :         MOZ_ASSERT(int32_t(mRefCnt) >= 0);
      70           0 :         ++mRefCnt;
      71           0 :     }
      72             : 
      73           0 :     void Release() const
      74             :     {
      75           0 :         MOZ_ASSERT(int32_t(mRefCnt) > 0);
      76           0 :         MozRefCountType cnt = --mRefCnt;
      77           0 :         if (0 == cnt) {
      78             : #ifdef DEBUG
      79           0 :             mRefCnt = DEAD;
      80             : #endif
      81           0 :             js_delete(const_cast<T*>(static_cast<const T*>(this)));
      82             :         }
      83           0 :     }
      84             : 
      85             :   private:
      86             :     mutable mozilla::Atomic<MozRefCountType> mRefCnt;
      87             : };
      88             : 
      89             : } // namespace js
      90             : 
      91             : #endif /* js_RefCounted_h */