mirror of
https://github.com/mollyim/webrtc.git
synced 2025-05-13 05:40:42 +01:00
8df643b387
To add ref counting to any class while avoiding virtual functions for reference counting. This template can both slightly reduce binary size and slightly improve performance. Bug: webrtc:11308 Change-Id: I90ac735f6c220ee2a1a991a71039acdb0ca86453 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/198845 Commit-Queue: Danil Chapovalov <danilchap@webrtc.org> Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org> Reviewed-by: Niels Moller <nisse@webrtc.org> Cr-Commit-Position: refs/heads/master@{#33058}
95 lines
3.1 KiB
C++
95 lines
3.1 KiB
C++
/*
|
|
* 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_
|