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/*
* Copyright 2016 The WebRTC Project Authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef RTC_BASE_REF_COUNTED_OBJECT_H_
#define RTC_BASE_REF_COUNTED_OBJECT_H_
#include "api/scoped_refptr.h"
#include "rtc_base/ref_count.h"
#include "rtc_base/ref_counter.h"
namespace webrtc {
template <class T>
class RefCountedObject : public T {
public:
RefCountedObject() {}
RefCountedObject(const RefCountedObject&) = delete;
RefCountedObject& operator=(const RefCountedObject&) = delete;
template <class P0>
explicit RefCountedObject(P0&& p0) : T(std::forward<P0>(p0)) {}
template <class P0, class P1, class... Args>
RefCountedObject(P0&& p0, P1&& p1, Args&&... args)
: T(std::forward<P0>(p0),
std::forward<P1>(p1),
std::forward<Args>(args)...) {}
void AddRef() const override { ref_count_.IncRef(); }
RefCountReleaseStatus Release() const override {
const auto status = ref_count_.DecRef();
if (status == RefCountReleaseStatus::kDroppedLastRef) {
delete this;
}
return status;
}
// Return whether the reference count is one. If the reference count is used
// in the conventional way, a reference count of 1 implies that the current
// thread owns the reference and no other thread shares it. This call
// performs the test for a reference count of one, and performs the memory
// barrier needed for the owning thread to act on the object, knowing that it
// has exclusive access to the object.
virtual bool HasOneRef() const { return ref_count_.HasOneRef(); }
protected:
~RefCountedObject() override {}
mutable webrtc::webrtc_impl::RefCounter ref_count_{0};
};
template <class T>
class FinalRefCountedObject final : public T {
public:
using T::T;
// Above using declaration propagates a default move constructor
// FinalRefCountedObject(FinalRefCountedObject&& other), but we also need
// move construction from T.
explicit FinalRefCountedObject(T&& other) : T(std::move(other)) {}
FinalRefCountedObject(const FinalRefCountedObject&) = delete;
FinalRefCountedObject& operator=(const FinalRefCountedObject&) = delete;
void AddRef() const { ref_count_.IncRef(); }
RefCountReleaseStatus Release() const {
const auto status = ref_count_.DecRef();
if (status == RefCountReleaseStatus::kDroppedLastRef) {
delete this;
}
return status;
}
bool HasOneRef() const { return ref_count_.HasOneRef(); }
private:
~FinalRefCountedObject() = default;
mutable webrtc::webrtc_impl::RefCounter ref_count_{0};
};
} // namespace webrtc
// Backwards compatibe aliases.
// TODO: https://issues.webrtc.org/42225969 - deprecate and remove.
namespace rtc {
// Because there are users of this template that use "friend
// rtc::RefCountedObject<>" to give access to a private destructor, some
// indirection is needed; "friend" declarations cannot span an "using"
// declaration. Since a templated class on top of a templated class can't access
// the subclass' protected members, we duplicate the entire class instead.
template <class T>
class RefCountedObject : public T {
public:
RefCountedObject() {}
RefCountedObject(const RefCountedObject&) = delete;
RefCountedObject& operator=(const RefCountedObject&) = delete;
template <class P0>
explicit RefCountedObject(P0&& p0) : T(std::forward<P0>(p0)) {}
template <class P0, class P1, class... Args>
RefCountedObject(P0&& p0, P1&& p1, Args&&... args)
: T(std::forward<P0>(p0),
std::forward<P1>(p1),
std::forward<Args>(args)...) {}
void AddRef() const override { ref_count_.IncRef(); }
webrtc::RefCountReleaseStatus Release() const override {
const auto status = ref_count_.DecRef();
if (status == webrtc::RefCountReleaseStatus::kDroppedLastRef) {
delete this;
}
return status;
}
// Return whether the reference count is one. If the reference count is used
// in the conventional way, a reference count of 1 implies that the current
// thread owns the reference and no other thread shares it. This call
// performs the test for a reference count of one, and performs the memory
// barrier needed for the owning thread to act on the object, knowing that it
// has exclusive access to the object.
virtual bool HasOneRef() const { return ref_count_.HasOneRef(); }
protected:
~RefCountedObject() override {}
mutable webrtc::webrtc_impl::RefCounter ref_count_{0};
};
template <typename T>
using FinalRefCountedObject = webrtc::FinalRefCountedObject<T>;
} // namespace rtc
#endif // RTC_BASE_REF_COUNTED_OBJECT_H_