Line data    Source code

       1              : /*
       2              :  *
       3              :  *    Copyright (c) 2025 Project CHIP Authors
       4              :  *
       5              :  *    Licensed under the Apache License, Version 2.0 (the "License");
       6              :  *    you may not use this file except in compliance with the License.
       7              :  *    You may obtain a copy of the License at
       8              :  *
       9              :  *        http://www.apache.org/licenses/LICENSE-2.0
      10              :  *
      11              :  *    Unless required by applicable law or agreed to in writing, software
      12              :  *    distributed under the License is distributed on an "AS IS" BASIS,
      13              :  *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      14              :  *    See the License for the specific language governing permissions and
      15              :  *    limitations under the License.
      16              :  */
      17              : 
      18              : /**
      19              :  *    @file
      20              :  *          Contains a standard RAII class which calls Release on dtor.
      21              :  */
      22              : 
      23              : #pragma once
      24              : 
      25              : #include <lib/support/CodeUtils.h>
      26              : #include <stddef.h>
      27              : 
      28              : namespace chip {
      29              : 
      30              : /// RAII class for iterators that guarantees that Release() will be called
      31              : /// on the underlying type.  This is effectively a simple unique_ptr, except
      32              : /// calling Release instead of delete
      33              : /// See also ReferenceCountedPtr<T>, which automatically retains a ReferenceCounted
      34              : template <typename Releasable>
      35              : class AutoRelease
      36              : {
      37              : public:
      38           13 :     AutoRelease(Releasable * releasable) : mReleasable(releasable) {}
      39           14 :     ~AutoRelease() { Release(); }
      40              : 
      41              :     // Not copyable
      42              :     AutoRelease(const AutoRelease &)             = delete;
      43              :     AutoRelease & operator=(const AutoRelease &) = delete;
      44              : 
      45            1 :     AutoRelease(AutoRelease && other) : mReleasable(other.mReleasable) { other.mReleasable = nullptr; }
      46            1 :     AutoRelease & operator=(AutoRelease && other)
      47              :     {
      48            1 :         if (this != &other)
      49              :         {
      50            1 :             Release();
      51            1 :             mReleasable       = other.mReleasable;
      52            1 :             other.mReleasable = nullptr;
      53              :         }
      54            1 :         return *this;
      55              :     }
      56              : 
      57           10 :     inline Releasable * operator->() { return mReleasable; }
      58              :     inline const Releasable * operator->() const { return mReleasable; }
      59              :     inline const Releasable & operator*() const { return *mReleasable; }
      60            3 :     inline Releasable & operator*() { return *mReleasable; }
      61              : 
      62              :     inline operator bool() { return mReleasable != nullptr; }
      63           11 :     inline bool IsNull() const { return mReleasable == nullptr; }
      64              : 
      65           27 :     void Release()
      66              :     {
      67           27 :         VerifyOrReturn(mReleasable != nullptr);
      68           14 :         mReleasable->Release();
      69           14 :         mReleasable = nullptr;
      70              :     }
      71              : 
      72            3 :     void Set(Releasable * releasable)
      73              :     {
      74            3 :         if (mReleasable != releasable)
      75              :         {
      76            2 :             Release();
      77            2 :             mReleasable = releasable;
      78              :         }
      79            3 :     }
      80              : 
      81              : protected:
      82              :     Releasable * mReleasable = nullptr;
      83              : };
      84              : 
      85              : // Template deduction guides to allow auto-release creation from pointers
      86              : template <class T>
      87              : AutoRelease(T * releasable) -> AutoRelease<T>;
      88              : 
      89              : } // namespace chip