blob: e86a1fba0d633e5a0ea5ba15f68861e0d5a7c6b6 [file] [log] [blame]
/*
* 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 <type_traits>
#include <utility>
#include "rtc_base/constructor_magic.h"
#include "rtc_base/ref_count.h"
#include "rtc_base/ref_counter.h"
namespace rtc {
template <class T>
class RefCountedObject : public T {
public:
RefCountedObject() {}
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)...) {}
virtual void AddRef() const { ref_count_.IncRef(); }
virtual RefCountReleaseStatus Release() const {
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:
virtual ~RefCountedObject() {}
mutable webrtc::webrtc_impl::RefCounter ref_count_{0};
RTC_DISALLOW_COPY_AND_ASSIGN(RefCountedObject);
};
template <class T>
class FinalRefCountedObject final : public T {
public:
using T::T;
// Until c++17 compilers are allowed not to inherit the default constructor,
// and msvc doesn't. Thus the default constructor is forwarded explicitly.
FinalRefCountedObject() = default;
FinalRefCountedObject(const FinalRefCountedObject&) = delete;
FinalRefCountedObject& operator=(const FinalRefCountedObject&) = delete;
void AddRef() const { ref_count_.IncRef(); }
void Release() const {
if (ref_count_.DecRef() == RefCountReleaseStatus::kDroppedLastRef) {
delete this;
}
}
bool HasOneRef() const { return ref_count_.HasOneRef(); }
private:
~FinalRefCountedObject() = default;
// gcc v7.1 requires default contructors for members of
// `FinalRefCountedObject` to be able to use inherited constructors.
// TODO(danilchap): Replace with simpler braced initialization when
// bot support for that version of gcc is dropped.
class ZeroBasedRefCounter : public webrtc::webrtc_impl::RefCounter {
public:
ZeroBasedRefCounter() : RefCounter(0) {}
} mutable ref_count_;
};
} // namespace rtc
#endif // RTC_BASE_REF_COUNTED_OBJECT_H_