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1 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- |
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2 * This Source Code Form is subject to the terms of the Mozilla Public |
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3 * License, v. 2.0. If a copy of the MPL was not distributed with this |
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4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
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5 |
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6 #ifndef MOZILLA_ATOMICREFCOUNTEDWITHFINALIZE_H_ |
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7 #define MOZILLA_ATOMICREFCOUNTEDWITHFINALIZE_H_ |
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8 |
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9 #include "mozilla/RefPtr.h" |
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10 #include "mozilla/NullPtr.h" |
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11 |
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12 namespace mozilla { |
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13 |
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14 template<typename T> |
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15 class AtomicRefCountedWithFinalize |
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16 { |
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17 protected: |
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18 AtomicRefCountedWithFinalize() |
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19 : mRecycleCallback(nullptr) |
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20 , mRefCount(0) |
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21 {} |
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22 |
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23 ~AtomicRefCountedWithFinalize() {} |
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24 |
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25 public: |
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26 void AddRef() { |
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27 MOZ_ASSERT(mRefCount >= 0); |
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28 ++mRefCount; |
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29 } |
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30 |
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31 void Release() { |
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32 MOZ_ASSERT(mRefCount > 0); |
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33 // Read mRecycleCallback early so that it does not get set to |
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34 // deleted memory, if the object is goes away. |
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35 RecycleCallback recycleCallback = mRecycleCallback; |
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36 int currCount = --mRefCount; |
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37 if (0 == currCount) { |
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38 // Recycle listeners must call ClearRecycleCallback |
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39 // before releasing their strong reference. |
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40 MOZ_ASSERT(mRecycleCallback == nullptr); |
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41 #ifdef DEBUG |
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42 mRefCount = detail::DEAD; |
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43 #endif |
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44 T* derived = static_cast<T*>(this); |
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45 derived->Finalize(); |
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46 delete derived; |
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47 } else if (1 == currCount && recycleCallback) { |
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48 T* derived = static_cast<T*>(this); |
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49 recycleCallback(derived, mClosure); |
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50 } |
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51 } |
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52 |
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53 typedef void (*RecycleCallback)(T* aObject, void* aClosure); |
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54 /** |
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55 * Set a callback responsible for recycling this object |
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56 * before it is finalized. |
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57 */ |
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58 void SetRecycleCallback(RecycleCallback aCallback, void* aClosure) |
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59 { |
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60 mRecycleCallback = aCallback; |
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61 mClosure = aClosure; |
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62 } |
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63 void ClearRecycleCallback() { SetRecycleCallback(nullptr, nullptr); } |
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64 |
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65 private: |
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66 RecycleCallback mRecycleCallback; |
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67 void *mClosure; |
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68 Atomic<int> mRefCount; |
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69 }; |
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70 |
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71 } |
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72 |
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73 #endif |