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https://github.com/kidfromjupiter/nearby.git
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71 lines
2.5 KiB
C++
71 lines
2.5 KiB
C++
// Copyright 2020 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "platform/impl/windows/condition_variable.h"
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namespace location {
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namespace nearby {
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namespace windows {
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// The ConditionVariable class is a synchronization primitive that can be used
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// to block a thread, or multiple threads at the same time, until another thread
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// both modifies a shared variable (the condition), and notifies the
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// ConditionVariable.
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ConditionVariable::ConditionVariable(api::Mutex* mutex)
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: mutex_(dynamic_cast<windows::Mutex&>(*mutex)) {
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InitializeCriticalSection(&critical_section_);
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}
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// Notifies all the waiters that condition state has changed.
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// TODO(b/184975123): replace with real implementation.
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void ConditionVariable::Notify() {
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EnterCriticalSection(&critical_section_);
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condition_variable_actual_.notify_all();
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LeaveCriticalSection(&critical_section_);
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}
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// Waits indefinitely for Notify to be called.
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// May return prematurely in case of interrupt, if supported by platform.
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// Returns kSuccess, or kInterrupted on interrupt.
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Exception ConditionVariable::Wait() {
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std::unique_lock<std::mutex> lock =
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std::unique_lock<std::mutex>(mutex_.GetWindowsMutex());
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condition_variable_actual_.wait(lock);
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return Exception{Exception::kSuccess};
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}
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// Waits while timeout has not expired for Notify to be called.
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// May return prematurely in case of interrupt, if supported by platform.
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// Returns kSuccess, or kInterrupted on interrupt.
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Exception ConditionVariable::Wait(absl::Duration timeout) {
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auto now = std::chrono::system_clock::now();
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std::unique_lock<std::mutex> lock =
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std::unique_lock<std::mutex>(mutex_.GetWindowsMutex());
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if (condition_variable_actual_.wait_until(
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lock, now + absl::ToChronoMilliseconds(timeout)) ==
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std::cv_status::timeout) {
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return Exception{Exception::kInterrupted};
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} else {
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return Exception{Exception::kSuccess};
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}
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}
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} // namespace windows
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} // namespace nearby
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} // namespace location
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