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// Copyright 2022 The Pigweed Authors
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.
#pragma once
#include <limits>
#include "pw_assert/assert.h"
#include "pw_sync/recursive_mutex.h"
namespace pw::sync {
inline RecursiveMutex::RecursiveMutex() : native_type_(0) {}
inline RecursiveMutex::~RecursiveMutex() = default;
inline void RecursiveMutex::lock() {
try_lock(); // Locking always succeeds
}
inline bool RecursiveMutex::try_lock() {
int lock_count = native_type_.fetch_add(1, std::memory_order_acquire);
PW_DASSERT(lock_count != std::numeric_limits<int>::max()); // Detect overflow
return true; // No threads, so you can always acquire a recursive mutex.
}
inline void RecursiveMutex::unlock() {
int lock_count = native_type_.fetch_sub(1, std::memory_order_release);
PW_ASSERT(lock_count > 0); // Unlocked mutex that wasn't held
}
inline RecursiveMutex::native_handle_type RecursiveMutex::native_handle() {
return native_type_;
}
} // namespace pw::sync