allwpilib/wpiutil/src/main/native/cpp/hostname.cpp

/*----------------------------------------------------------------------------*/
/* Copyright (c) 2017-2018 FIRST. All Rights Reserved.                        */
/* Open Source Software - may be modified and shared by FRC teams. The code   */
/* must be accompanied by the FIRST BSD license file in the root directory of */
/* the project.                                                               */
/*----------------------------------------------------------------------------*/

#include "wpi/hostname.h"

#include <cstdlib>
#include <string>

#include "uv.h"
#include "wpi/SmallVector.h"
#include "wpi/StringRef.h"

namespace wpi {

std::string GetHostname() {
  std::string rv;
  char name[256];
  size_t size = sizeof(name);

  int err = uv_os_gethostname(name, &size);
  if (err == 0) {
    rv.assign(name, size);
  } else if (err == UV_ENOBUFS) {
    char* name2 = static_cast<char*>(std::malloc(size));
    err = uv_os_gethostname(name2, &size);
    if (err == 0) rv.assign(name2, size);
    std::free(name2);
  }

  return rv;
}

StringRef GetHostname(SmallVectorImpl<char>& name) {
  // Use a tmp array to not require the SmallVector to be too large.
  char tmpName[256];
  size_t size = sizeof(tmpName);

  name.clear();

  int err = uv_os_gethostname(tmpName, &size);
  if (err == 0) {
    name.append(tmpName, tmpName + size);
  } else if (err == UV_ENOBUFS) {
    name.resize(size);
    err = uv_os_gethostname(name.data(), &size);
    if (err != 0) size = 0;
  }

  return StringRef{name.data(), size};
}

}  // namespace wpi