// 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.

#ifndef IMPALA_UTIL_OS_INFO_H
#define IMPALA_UTIL_OS_INFO_H

#include <time.h>

#include <string>

#include "common/logging.h"

namespace impala {

/// Provides information about the OS we're running on.
class OsInfo {
 public:
  /// Initialize OsInfo.
  static void Init();

  /// Simple name of the OS.
  /// If Docker is used this is the name of Container OS.
  static const std::string os_distribution() {
    DCHECK(initialized_);
    return os_distribution_;
  }

  /// The version of Linux kernel and the version of the compiler used to build it.
  /// If Docker is used this is the host kernel.
  static const std::string os_version() {
    DCHECK(initialized_);
    return os_version_;
  }

  /// Return CLOCK_MONOTONIC if it's fast. Otherwise CLOCK_MONOTONIC_COARSE, which will be
  /// fast but lower resolution.
  static clockid_t fast_clock() {
    DCHECK(initialized_);
    return fast_clock_;
  }

  static std::string DebugString();

 private:
  static bool initialized_;
  static std::string os_distribution_;
  static std::string os_version_;
  static clockid_t fast_clock_;
  static std::string clock_name_;
};

}
#endif