mirror of
https://github.com/kidfromjupiter/nearby.git
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91 lines
2.4 KiB
C++
91 lines
2.4 KiB
C++
// Copyright 2021 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/mutex.h"
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namespace location {
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namespace nearby {
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namespace windows {
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// A lock is a tool for controlling access to a shared resource by multiple
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// threads.
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//
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// https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/locks/Lock.html
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Mutex::Mutex(Mutex::Mode mode)
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: mode_(mode), owning_thread_(std::this_thread::get_id()) {
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InitializeCriticalSection(&critical_section_);
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}
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void Mutex::Lock() {
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EnterCriticalSection(&critical_section_);
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std::thread::id currentThread = std::this_thread::get_id();
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if ((mode_ == Mutex::Mode::kRegular ||
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mode_ == Mutex::Mode::kRegularNoCheck) &&
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!locked_) {
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mutex_actual_.lock();
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owning_thread_ = currentThread;
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locked_ = true;
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}
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if (mode_ == Mutex::Mode::kRecursive) {
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if (!locked_) {
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owning_thread_ = currentThread;
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}
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if (owning_thread_ == currentThread) {
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try {
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recursive_mutex_actual_.lock();
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} catch ([[maybe_unused]] const std::system_error& e) {
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// Eat the exception and fail silently, argument left for debug
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}
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locked_ = true;
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}
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}
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LeaveCriticalSection(&critical_section_);
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}
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void Mutex::Unlock() {
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EnterCriticalSection(&critical_section_);
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std::thread::id currentThread = std::this_thread::get_id();
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if (mode_ == Mutex::Mode::kRegular || mode_ == Mutex::Mode::kRegularNoCheck) {
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if (currentThread == owning_thread_) {
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mutex_actual_.unlock();
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locked_ = false;
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}
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}
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if (mode_ == Mutex::Mode::kRecursive) {
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if (currentThread == owning_thread_) {
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recursive_mutex_actual_.unlock();
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locked_ = false;
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}
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}
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LeaveCriticalSection(&critical_section_);
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}
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std::mutex& Mutex::GetWindowsMutex() { return mutex_; }
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std::recursive_mutex& Mutex::GetWindowsRecursiveMutex() {
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return recursive_mutex_;
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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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