src/system/SystemObject.cpp

/*
 *
 *    Copyright (c) 2020 Project CHIP Authors
 *    Copyright (c) 2016-2017 Nest Labs, Inc.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */

/**
 *    @file
 *      This file contains definitions of member functions for class
 *      chip::System::Object.
 */

// Include module header
#include <system/SystemObject.h>

// Include common private header
#include "SystemLayerPrivate.h"

// Include local headers
#include <lib/support/CodeUtils.h>
#include <system/SystemLayer.h>

// Include local headers
#include <stddef.h>
#include <stdlib.h>

namespace chip {
namespace System {

/**
 *  @brief
 *      Decrements the reference count for the CHIP System Layer object. Recycles the object back into the pool if the reference
 *      count is decremented to zero. No destructor is invoked.
 */
DLL_EXPORT void Object::Release()
{
    unsigned int oldCount = __sync_fetch_and_sub(&this->mRefCount, 1);

    if (oldCount == 1)
    {
#if CHIP_SYSTEM_CONFIG_POOL_USE_HEAP
        std::lock_guard<std::mutex> lock(*mMutexRef);
        this->mPrev->mNext = this->mNext;
        if (this->mNext)
            this->mNext->mPrev = this->mPrev;
        delete this;
#endif
        __sync_synchronize();
    }
    else if (oldCount == 0)
    {
        abort();
    }
}

DLL_EXPORT bool Object::TryCreate(size_t aOctets)
{
    if (!__sync_bool_compare_and_swap(&this->mRefCount, 0, 1))
    {
        return false; // object already in use
    }

    this->AppState = nullptr;
    memset(reinterpret_cast<char *>(this) + sizeof(*this), 0, aOctets - sizeof(*this));

    return true;
}

#if CHIP_SYSTEM_CONFIG_USE_LWIP
void Object::DeferredRelease(LayerLwIP * aSystemLayer, Object::ReleaseDeferralErrorTactic aTactic)
{
    VerifyOrReturn(aSystemLayer != nullptr, ChipLogError(chipSystemLayer, "aSystemLayer is nullptr"));

    CHIP_ERROR lError = aSystemLayer->ScheduleLambda([this] { this->Release(); });

    if (lError != CHIP_NO_ERROR)
    {
        switch (aTactic)
        {
        case kReleaseDeferralErrorTactic_Ignore:
            break;

        case kReleaseDeferralErrorTactic_Release:
            this->Release();
            break;

        case kReleaseDeferralErrorTactic_Die:
            VerifyOrDieWithMsg(false, chipSystemLayer, "Object::DeferredRelease %p->PostEvent failed err(%" CHIP_ERROR_FORMAT ")",
                               aSystemLayer, lError.Format());
            break;
        }
    }
}
#endif // CHIP_SYSTEM_CONFIG_USE_LWIP

} // namespace System
} // namespace chip