/*
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * 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
 *
 *     http://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 <atomic>
#include <cstdint>

namespace folly {

//  atomic_compare_exchange_weak_explicit
//
//  Fix TSAN bug in std::atomic_compare_exchange_weak_explicit.
//  Workaround for https://github.com/google/sanitizers/issues/970.
//
//  mimic: std::atomic_compare_exchange_weak
template <typename T>
bool atomic_compare_exchange_weak_explicit(
    std::atomic<T>* obj,
    T* expected,
    T desired,
    std::memory_order succ,
    std::memory_order fail);

//  atomic_compare_exchange_strong_explicit
//
//  Fix TSAN bug in std::atomic_compare_exchange_strong_explicit.
//  Workaround for https://github.com/google/sanitizers/issues/970.
//
//  mimic: std::atomic_compare_exchange_strong
template <typename T>
bool atomic_compare_exchange_strong_explicit(
    std::atomic<T>* obj,
    T* expected,
    T desired,
    std::memory_order succ,
    std::memory_order fail);

//  atomic_fetch_set
//
//  Sets the bit at the given index in the binary representation of the integer
//  to 1. Returns the previous value of the bit, which is equivalent to whether
//  that bit is unchanged.
//
//  Equivalent to Atomic::fetch_or with a mask. For example, if the bit
//  argument to this function is 1, the mask passed to the corresponding
//  Atomic::fetch_or would be 0b1.
//
//  Uses an optimized implementation when available, otherwise falling back to
//  Atomic::fetch_or with mask. The optimization is currently available for
//  std::atomic on x86, using the bts instruction.
template <typename Atomic>
bool atomic_fetch_set(
    Atomic& atomic,
    std::size_t bit,
    std::memory_order order = std::memory_order_seq_cst);

//  atomic_fetch_reset
//
//  Resets the bit at the given index in the binary representation of the
//  integer to 0. Returns the previous value of the bit, which is equivalent to
//  whether that bit is changed.
//
//  Equivalent to Atomic::fetch_and with a mask. For example, if the bit
//  argument to this function is 1, the mask passed to the corresponding
//  Atomic::fetch_and would be ~0b1.
//
//  Uses an optimized implementation when available, otherwise falling back to
//  Atomic::fetch_and with mask. The optimization is currently available for
//  std::atomic on x86, using the btr instruction.
template <typename Atomic>
bool atomic_fetch_reset(
    Atomic& atomic,
    std::size_t bit,
    std::memory_order order = std::memory_order_seq_cst);

} // namespace folly

#include <folly/synchronization/AtomicUtil-inl.h>