text: // 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 PEGASUS_UTIL_OS_INFO_H
  #define PEGASUS_UTIL_OS_INFO_H
  
  #include <time.h>
  
  #include <string>
  
  #include "common/logging.h"
  
  namespace pegasus {
  
  /// 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
  