85 lines
2.6 KiB
C++
85 lines
2.6 KiB
C++
/*
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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/operations_chain.h"
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#include "rtc_base/checks.h"
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namespace rtc {
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OperationsChain::CallbackHandle::CallbackHandle(
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scoped_refptr<OperationsChain> operations_chain)
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: operations_chain_(std::move(operations_chain)) {}
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OperationsChain::CallbackHandle::~CallbackHandle() {
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#if RTC_DCHECK_IS_ON
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RTC_DCHECK(has_run_);
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#endif
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}
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void OperationsChain::CallbackHandle::OnOperationComplete() {
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#if RTC_DCHECK_IS_ON
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RTC_DCHECK(!has_run_);
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has_run_ = true;
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#endif // RTC_DCHECK_IS_ON
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operations_chain_->OnOperationComplete();
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// We have no reason to keep the `operations_chain_` alive through reference
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// counting anymore.
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operations_chain_ = nullptr;
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}
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// static
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scoped_refptr<OperationsChain> OperationsChain::Create() {
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return new OperationsChain();
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}
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OperationsChain::OperationsChain() : RefCountedObject() {
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RTC_DCHECK_RUN_ON(&sequence_checker_);
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}
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OperationsChain::~OperationsChain() {
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// Operations keep the chain alive through reference counting so this should
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// not be possible. The fact that the chain is empty makes it safe to
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// destroy the OperationsChain on any sequence.
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RTC_DCHECK(chained_operations_.empty());
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}
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void OperationsChain::SetOnChainEmptyCallback(
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std::function<void()> on_chain_empty_callback) {
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RTC_DCHECK_RUN_ON(&sequence_checker_);
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on_chain_empty_callback_ = std::move(on_chain_empty_callback);
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}
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bool OperationsChain::IsEmpty() const {
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RTC_DCHECK_RUN_ON(&sequence_checker_);
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return chained_operations_.empty();
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}
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std::function<void()> OperationsChain::CreateOperationsChainCallback() {
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return [handle = rtc::scoped_refptr<CallbackHandle>(
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new CallbackHandle(this))]() { handle->OnOperationComplete(); };
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}
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void OperationsChain::OnOperationComplete() {
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RTC_DCHECK_RUN_ON(&sequence_checker_);
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// The front element is the operation that just completed, remove it.
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RTC_DCHECK(!chained_operations_.empty());
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chained_operations_.pop();
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// If there are any other operations chained, execute the next one. Otherwise,
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// invoke the "on chain empty" callback if it has been set.
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if (!chained_operations_.empty()) {
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chained_operations_.front()->Run();
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} else if (on_chain_empty_callback_.has_value()) {
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on_chain_empty_callback_.value()();
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}
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}
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} // namespace rtc
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