// Licensed to the Apache Software Foundation (ASF) under one

// or more contributor license agreements.  See the NOTICE file

// distributed with this work for additional information

// regarding copyright ownership.  The ASF licenses this file

// to you 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 <chrono>

#include <mutex>

namespace doris {

class Ticker {

public:

    virtual ~Ticker() = default;

    /**

     * Returns the number of nanoseconds since a fixed reference point

     */

    virtual int64_t read() const = 0;

protected:

    Ticker() = default;

};

class SystemTicker : public Ticker {

public:

    int64_t read() const override {

        return std::chrono::duration_cast<std::chrono::nanoseconds>(

                       std::chrono::steady_clock::now().time_since_epoch())

                .count();

    }

};

} // namespace doris