66 lines
2.0 KiB
C++
66 lines
2.0 KiB
C++
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/*
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* Copyright 2019 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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#include "rtc_base/synchronization/sequence_checker.h"
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#if defined(WEBRTC_MAC)
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#include <dispatch/dispatch.h>
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#endif
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namespace webrtc {
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namespace {
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// On Mac, returns the label of the current dispatch queue; elsewhere, return
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// null.
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const void* GetSystemQueueRef() {
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#if defined(WEBRTC_MAC)
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return dispatch_queue_get_label(DISPATCH_CURRENT_QUEUE_LABEL);
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#else
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return nullptr;
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#endif
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}
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} // namespace
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SequenceCheckerImpl::SequenceCheckerImpl()
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: attached_(true),
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valid_thread_(rtc::CurrentThreadRef()),
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valid_queue_(TaskQueueBase::Current()),
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valid_system_queue_(GetSystemQueueRef()) {}
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SequenceCheckerImpl::~SequenceCheckerImpl() = default;
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bool SequenceCheckerImpl::IsCurrent() const {
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const TaskQueueBase* const current_queue = TaskQueueBase::Current();
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const rtc::PlatformThreadRef current_thread = rtc::CurrentThreadRef();
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const void* const current_system_queue = GetSystemQueueRef();
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rtc::CritScope scoped_lock(&lock_);
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if (!attached_) { // Previously detached.
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attached_ = true;
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valid_thread_ = current_thread;
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valid_queue_ = current_queue;
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valid_system_queue_ = current_system_queue;
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return true;
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}
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if (valid_queue_ || current_queue) {
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return valid_queue_ == current_queue;
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}
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if (valid_system_queue_ && valid_system_queue_ == current_system_queue) {
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return true;
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}
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return rtc::IsThreadRefEqual(valid_thread_, current_thread);
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}
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void SequenceCheckerImpl::Detach() {
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rtc::CritScope scoped_lock(&lock_);
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attached_ = false;
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// We don't need to touch the other members here, they will be
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// reset on the next call to IsCurrent().
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}
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} // namespace webrtc
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