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a8c7326524
Bug: webrtc:10198 Change-Id: Icbcb849bdc789d9e3bb7ea6a902475a8263980bf Reviewed-on: https://webrtc-review.googlesource.com/c/117300 Commit-Queue: Karl Wiberg <kwiberg@webrtc.org> Reviewed-by: Niels Moller <nisse@webrtc.org> Cr-Commit-Position: refs/heads/master@{#26242}
54 lines
2 KiB
C++
54 lines
2 KiB
C++
/*
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* Copyright 2017 The WebRTC Project Authors. All rights reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef RTC_BASE_REF_COUNTER_H_
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#define RTC_BASE_REF_COUNTER_H_
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#include "rtc_base/atomic_ops.h"
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#include "rtc_base/ref_count.h"
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namespace webrtc {
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namespace webrtc_impl {
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class RefCounter {
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public:
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explicit RefCounter(int ref_count) : ref_count_(ref_count) {}
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RefCounter() = delete;
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void IncRef() { rtc::AtomicOps::Increment(&ref_count_); }
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// Returns kDroppedLastRef if this call dropped the last reference; the caller
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// should therefore free the resource protected by the reference counter.
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// Otherwise, returns kOtherRefsRemained (note that in case of multithreading,
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// some other caller may have dropped the last reference by the time this call
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// returns; all we know is that we didn't do it).
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rtc::RefCountReleaseStatus DecRef() {
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return (rtc::AtomicOps::Decrement(&ref_count_) == 0)
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? rtc::RefCountReleaseStatus::kDroppedLastRef
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: rtc::RefCountReleaseStatus::kOtherRefsRemained;
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}
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// Return whether the reference count is one. If the reference count is used
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// in the conventional way, a reference count of 1 implies that the current
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// thread owns the reference and no other thread shares it. This call performs
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// the test for a reference count of one, and performs the memory barrier
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// needed for the owning thread to act on the resource protected by the
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// reference counter, knowing that it has exclusive access.
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bool HasOneRef() const {
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return rtc::AtomicOps::AcquireLoad(&ref_count_) == 1;
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}
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private:
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volatile int ref_count_;
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};
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} // namespace webrtc_impl
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} // namespace webrtc
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#endif // RTC_BASE_REF_COUNTER_H_
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