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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 17:32:43 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 17:32:43 +0000 |
commit | 6bf0a5cb5034a7e684dcc3500e841785237ce2dd (patch) | |
tree | a68f146d7fa01f0134297619fbe7e33db084e0aa /third_party/libwebrtc/api/ref_counted_base.h | |
parent | Initial commit. (diff) | |
download | thunderbird-upstream.tar.xz thunderbird-upstream.zip |
Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | third_party/libwebrtc/api/ref_counted_base.h | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/third_party/libwebrtc/api/ref_counted_base.h b/third_party/libwebrtc/api/ref_counted_base.h new file mode 100644 index 0000000000..f20228b740 --- /dev/null +++ b/third_party/libwebrtc/api/ref_counted_base.h @@ -0,0 +1,98 @@ +/* + * Copyright 2017 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 API_REF_COUNTED_BASE_H_ +#define API_REF_COUNTED_BASE_H_ + +#include <type_traits> + +#include "rtc_base/ref_counter.h" + +namespace rtc { + +class RefCountedBase { + public: + RefCountedBase() = default; + + RefCountedBase(const RefCountedBase&) = delete; + RefCountedBase& operator=(const RefCountedBase&) = delete; + + void AddRef() const { ref_count_.IncRef(); } + RefCountReleaseStatus Release() const { + const auto status = ref_count_.DecRef(); + if (status == RefCountReleaseStatus::kDroppedLastRef) { + delete this; + } + return status; + } + + protected: + // Provided for internal webrtc subclasses for corner cases where it's + // necessary to know whether or not a reference is exclusively held. + bool HasOneRef() const { return ref_count_.HasOneRef(); } + + virtual ~RefCountedBase() = default; + + private: + mutable webrtc::webrtc_impl::RefCounter ref_count_{0}; +}; + +// Template based version of `RefCountedBase` for simple implementations that do +// not need (or want) destruction via virtual destructor or the overhead of a +// vtable. +// +// To use: +// struct MyInt : public rtc::RefCountedNonVirtual<MyInt> { +// int foo_ = 0; +// }; +// +// rtc::scoped_refptr<MyInt> my_int(new MyInt()); +// +// sizeof(MyInt) on a 32 bit system would then be 8, int + refcount and no +// vtable generated. +template <typename T> +class RefCountedNonVirtual { + public: + RefCountedNonVirtual() = default; + + RefCountedNonVirtual(const RefCountedNonVirtual&) = delete; + RefCountedNonVirtual& operator=(const RefCountedNonVirtual&) = delete; + + void AddRef() const { ref_count_.IncRef(); } + RefCountReleaseStatus Release() const { + // If you run into this assert, T has virtual methods. There are two + // options: + // 1) The class doesn't actually need virtual methods, the type is complete + // so the virtual attribute(s) can be removed. + // 2) The virtual methods are a part of the design of the class. In this + // case you can consider using `RefCountedBase` instead or alternatively + // use `rtc::RefCountedObject`. + static_assert(!std::is_polymorphic<T>::value, + "T has virtual methods. RefCountedBase is a better fit."); + const auto status = ref_count_.DecRef(); + if (status == RefCountReleaseStatus::kDroppedLastRef) { + delete static_cast<const T*>(this); + } + return status; + } + + protected: + // Provided for internal webrtc subclasses for corner cases where it's + // necessary to know whether or not a reference is exclusively held. + bool HasOneRef() const { return ref_count_.HasOneRef(); } + + ~RefCountedNonVirtual() = default; + + private: + mutable webrtc::webrtc_impl::RefCounter ref_count_{0}; +}; + +} // namespace rtc + +#endif // API_REF_COUNTED_BASE_H_ |