third_party/WebKit/Source/platform/mac/VersionUtilMac.mm

// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#import "platform/mac/VersionUtilMac.h"

#include <sstream>
#include <string>
#include <sys/utsname.h>

namespace {

// Returns the running system's Darwin major version. Don't call this, it's
// an implementation detail and its result is meant to be cached by
// MacOSXMinorVersion.
int DarwinMajorVersionInternal() {
  // The implementation of this method was copied from Chromium, with minor
  // modifications to avoid the use of methods in base/. For further details,
  // see
  // https://code.google.com/p/chromium/codesearch#chromium/src/base/mac/mac_util.mm
  struct utsname unameInfo;
  if (uname(&unameInfo) != 0)
    return 0;

  if (strcmp(unameInfo.sysname, "Darwin") != 0)
    return 0;

  std::string releaseString(unameInfo.release);
  size_t pos = releaseString.find_first_of('.');
  if (pos == std::string::npos)
    return 0;

  std::istringstream convert(releaseString.substr(0, pos));
  int majorVersion;
  if (!(convert >> majorVersion))
    return 0;

  return majorVersion;
}

// Returns the running system's Mac OS X minor version. This is the |y| value
// in 10.y or 10.y.z. Don't call this, it's an implementation detail and the
// result is meant to be cached by MacOSXMinorVersion.
int MacOSXMinorVersionInternal() {
  int darwinMajorVersion = DarwinMajorVersionInternal();
  return darwinMajorVersion - 4;
}

}  // namespace

// Returns the running system's Mac OS X minor version. This is the |y| value
// in 10.y or 10.y.z.
int blink::internal::MacOSXMinorVersion() {
  static int minor_version = MacOSXMinorVersionInternal();
  return minor_version;
}