blob: 25d5cdcdde6c529db93ac5fb38ec3d6faa162182 [file] [log] [blame]
/*
*
* Copyright (c) 2020 Project CHIP Authors
*
* 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 defines a C++ referenced counted object that auto deletes when
* all references to it have been removed.
*/
#pragma once
#include <atomic>
#include <limits>
#include <stdlib.h>
#include <lib/support/CHIPMem.h>
#include <lib/support/CodeUtils.h>
namespace chip {
template <class T>
class DeleteDeletor
{
public:
static void Release(T * obj) { chip::Platform::Delete(obj); }
};
template <class T>
class NoopDeletor
{
public:
static void Release(T * obj) {}
};
/**
* A reference counted object maintains a count of usages and when the usage
* count drops to 0, it deletes itself.
*/
template <class Subclass, class Deletor = DeleteDeletor<Subclass>, int kInitRefCount = 1, typename CounterType = uint32_t>
class ReferenceCounted
{
public:
/** Adds one to the usage count of this class */
Subclass * Retain()
{
VerifyOrDie(!kInitRefCount || mRefCount > 0);
VerifyOrDie(mRefCount < std::numeric_limits<CounterType>::max());
++mRefCount;
return static_cast<Subclass *>(this);
}
/** Release usage of this class */
void Release()
{
VerifyOrDie(mRefCount != 0);
if (--mRefCount == 0)
{
Deletor::Release(static_cast<Subclass *>(this));
}
}
/** Get the current reference counter value */
CounterType GetReferenceCount() const { return mRefCount; }
private:
CounterType mRefCount = kInitRefCount;
};
} // namespace chip