nodejs/configure

#!/usr/bin/env python
import optparse
import os
import pprint
import re
import shlex
import subprocess
import sys
import shutil
import string

# gcc and g++ as defaults matches what GYP's Makefile generator does,
# except on OS X.
CC = os.environ.get('CC', 'cc' if sys.platform == 'darwin' else 'gcc')
CXX = os.environ.get('CXX', 'c++' if sys.platform == 'darwin' else 'g++')

root_dir = os.path.dirname(__file__)
sys.path.insert(0, os.path.join(root_dir, 'tools', 'gyp', 'pylib'))
from gyp.common import GetFlavor

# imports in tools/configure.d
sys.path.insert(0, os.path.join(root_dir, 'tools', 'configure.d'))
import nodedownload

# parse our options
parser = optparse.OptionParser()

valid_os = ('win', 'mac', 'solaris', 'freebsd', 'openbsd', 'linux', 'android')
valid_arch = ('arm', 'arm64', 'ia32', 'mips', 'mipsel', 'ppc', 'ppc64', 'x32',
              'x64', 'x86')
valid_arm_float_abi = ('soft', 'softfp', 'hard')
valid_mips_arch = ('loongson', 'r1', 'r2', 'r6', 'rx')
valid_mips_fpu = ('fp32', 'fp64', 'fpxx')
valid_mips_float_abi = ('soft', 'hard')
valid_intl_modes = ('none', 'small-icu', 'full-icu', 'system-icu')

# create option groups
shared_optgroup = optparse.OptionGroup(parser, "Shared libraries",
    "Flags that allows you to control whether you want to build against "
    "built-in dependencies or its shared representations. If necessary, "
    "provide multiple libraries with comma.")
intl_optgroup = optparse.OptionGroup(parser, "Internationalization",
    "Flags that lets you enable i18n features in io.js as well as which "
    "library you want to build against.")

# Options should be in alphabetical order but keep --prefix at the top,
# that's arguably the one people will be looking for most.
parser.add_option('--prefix',
    action='store',
    dest='prefix',
    default='/usr/local',
    help='select the install prefix [default: %default]')

parser.add_option('--debug',
    action='store_true',
    dest='debug',
    help='also build debug build')

parser.add_option('--dest-cpu',
    action='store',
    dest='dest_cpu',
    choices=valid_arch,
    help='CPU architecture to build for ({0})'.format(', '.join(valid_arch)))

parser.add_option('--dest-os',
    action='store',
    dest='dest_os',
    choices=valid_os,
    help='operating system to build for ({0})'.format(', '.join(valid_os)))

parser.add_option('--gdb',
    action='store_true',
    dest='gdb',
    help='add gdb support')

parser.add_option('--no-ifaddrs',
    action='store_true',
    dest='no_ifaddrs',
    help='use on deprecated SunOS systems that do not support ifaddrs.h')

parser.add_option("--fully-static",
    action="store_true",
    dest="fully_static",
    help="Generate an executable without external dynamic libraries. This "
         "will not work on OSX when using default compilation environment")

parser.add_option("--openssl-no-asm",
    action="store_true",
    dest="openssl_no_asm",
    help="Do not build optimized assembly for OpenSSL")

parser.add_option('--openssl-fips',
    action='store',
    dest='openssl_fips',
    help='Build OpenSSL using FIPS canister .o file in supplied folder')

shared_optgroup.add_option('--shared-http-parser',
    action='store_true',
    dest='shared_http_parser',
    help='link to a shared http_parser DLL instead of static linking')

shared_optgroup.add_option('--shared-http-parser-includes',
    action='store',
    dest='shared_http_parser_includes',
    help='directory containing http_parser header files')

shared_optgroup.add_option('--shared-http-parser-libname',
    action='store',
    dest='shared_http_parser_libname',
    default='http_parser',
    help='alternative lib name to link to [default: %default]')

shared_optgroup.add_option('--shared-http-parser-libpath',
    action='store',
    dest='shared_http_parser_libpath',
    help='a directory to search for the shared http_parser DLL')

shared_optgroup.add_option('--shared-libuv',
    action='store_true',
    dest='shared_libuv',
    help='link to a shared libuv DLL instead of static linking')

shared_optgroup.add_option('--shared-libuv-includes',
    action='store',
    dest='shared_libuv_includes',
    help='directory containing libuv header files')

shared_optgroup.add_option('--shared-libuv-libname',
    action='store',
    dest='shared_libuv_libname',
    default='uv',
    help='alternative lib name to link to [default: %default]')

shared_optgroup.add_option('--shared-libuv-libpath',
    action='store',
    dest='shared_libuv_libpath',
    help='a directory to search for the shared libuv DLL')

shared_optgroup.add_option('--shared-openssl',
    action='store_true',
    dest='shared_openssl',
    help='link to a shared OpenSSl DLL instead of static linking')

shared_optgroup.add_option('--shared-openssl-includes',
    action='store',
    dest='shared_openssl_includes',
    help='directory containing OpenSSL header files')

shared_optgroup.add_option('--shared-openssl-libname',
    action='store',
    dest='shared_openssl_libname',
    default='crypto,ssl',
    help='alternative lib name to link to [default: %default]')

shared_optgroup.add_option('--shared-openssl-libpath',
    action='store',
    dest='shared_openssl_libpath',
    help='a directory to search for the shared OpenSSL DLLs')

shared_optgroup.add_option('--shared-zlib',
    action='store_true',
    dest='shared_zlib',
    help='link to a shared zlib DLL instead of static linking')

shared_optgroup.add_option('--shared-zlib-includes',
    action='store',
    dest='shared_zlib_includes',
    help='directory containing zlib header files')

shared_optgroup.add_option('--shared-zlib-libname',
    action='store',
    dest='shared_zlib_libname',
    default='z',
    help='alternative lib name to link to [default: %default]')

shared_optgroup.add_option('--shared-zlib-libpath',
    action='store',
    dest='shared_zlib_libpath',
    help='a directory to search for the shared zlib DLL')

parser.add_option_group(shared_optgroup)

# TODO document when we've decided on what the tracing API and its options will
# look like
parser.add_option('--systemtap-includes',
    action='store',
    dest='systemtap_includes',
    help=optparse.SUPPRESS_HELP)

parser.add_option('--tag',
    action='store',
    dest='tag',
    help='custom build tag')

parser.add_option('--release-urlbase',
    action='store',
    dest='release_urlbase',
    help='Provide a custom URL prefix for the `process.release` properties '
         '`sourceUrl` and `headersUrl`. When compiling a release build, this '
         'will default to https://iojs.org/download/release/')

parser.add_option('--v8-options',
    action='store',
    dest='v8_options',
    help='v8 options to pass, see `node --v8-options` for examples.')

parser.add_option('--with-arm-float-abi',
    action='store',
    dest='arm_float_abi',
    choices=valid_arm_float_abi,
    help='specifies which floating-point ABI to use ({0}).'.format(
        ', '.join(valid_arm_float_abi)))

parser.add_option('--with-mips-arch-variant',
    action='store',
    dest='mips_arch_variant',
    default='r2',
    choices=valid_mips_arch,
    help='MIPS arch variant ({0}) [default: %default]'.format(
        ', '.join(valid_mips_arch)))

parser.add_option('--with-mips-fpu-mode',
    action='store',
    dest='mips_fpu_mode',
    default='fp32',
    choices=valid_mips_fpu,
    help='MIPS FPU mode ({0}) [default: %default]'.format(
        ', '.join(valid_mips_fpu)))

parser.add_option('--with-mips-float-abi',
    action='store',
    dest='mips_float_abi',
    default='hard',
    choices=valid_mips_float_abi,
    help='MIPS floating-point ABI ({0}) [default: %default]'.format(
        ', '.join(valid_mips_float_abi)))

parser.add_option('--with-dtrace',
    action='store_true',
    dest='with_dtrace',
    help='build with DTrace (default is true on sunos and darwin)')

parser.add_option('--with-lttng',
    action='store_true',
    dest='with_lttng',
    help='build with Lttng (Only available to Linux)')

parser.add_option('--with-etw',
    action='store_true',
    dest='with_etw',
    help='build with ETW (default is true on Windows)')

intl_optgroup.add_option('--with-intl',
    action='store',
    dest='with_intl',
    default='none',
    choices=valid_intl_modes,
    help='Intl mode (valid choices: {0}) [default: %default]'.format(
        ', '.join(valid_intl_modes)))

intl_optgroup.add_option('--with-icu-path',
    action='store',
    dest='with_icu_path',
    help='Path to icu.gyp (ICU i18n, Chromium version only.)')

intl_optgroup.add_option('--with-icu-locales',
    action='store',
    dest='with_icu_locales',
    default='root,en',
    help='Comma-separated list of locales for "small-icu". "root" is assumed. '
        '[default: %default]')

intl_optgroup.add_option('--with-icu-source',
    action='store',
    dest='with_icu_source',
    help='Intl mode: optional local path to icu/ dir, or path/URL of icu source archive.')

intl_optgroup.add_option('--download',
    action='store',
    dest='download_list',
    help=nodedownload.help())

parser.add_option_group(intl_optgroup)

parser.add_option('--with-perfctr',
    action='store_true',
    dest='with_perfctr',
    help='build with performance counters (default is true on Windows)')

parser.add_option('--without-dtrace',
    action='store_true',
    dest='without_dtrace',
    help='build without DTrace')

parser.add_option('--without-etw',
    action='store_true',
    dest='without_etw',
    help='build without ETW')

parser.add_option('--without-npm',
    action='store_true',
    dest='without_npm',
    help='don\'t install the bundled npm package manager')

parser.add_option('--without-perfctr',
    action='store_true',
    dest='without_perfctr',
    help='build without performance counters')

# Dummy option for backwards compatibility
parser.add_option('--with-snapshot',
    action='store_true',
    dest='unused_with_snapshot',
    help=optparse.SUPPRESS_HELP)

parser.add_option('--without-snapshot',
    action='store_true',
    dest='without_snapshot',
    help=optparse.SUPPRESS_HELP)

parser.add_option('--without-ssl',
    action='store_true',
    dest='without_ssl',
    help='build without SSL')

parser.add_option('--xcode',
    action='store_true',
    dest='use_xcode',
    help='generate build files for use with xcode')

parser.add_option('--enable-static',
    action='store_true',
    dest='enable_static',
    help='build as static library')

(options, args) = parser.parse_args()

# set up auto-download list
auto_downloads = nodedownload.parse(options.download_list)


def warn(msg):
  warn.warned = True
  prefix = '\033[1m\033[93mWARNING\033[0m' if os.isatty(1) else 'WARNING'
  print('%s: %s' % (prefix, msg))

# track if warnings occured
warn.warned = False

def b(value):
  """Returns the string 'true' if value is truthy, 'false' otherwise."""
  if value:
    return 'true'
  else:
    return 'false'


def pkg_config(pkg):
  pkg_config = os.environ.get('PKG_CONFIG', 'pkg-config')
  args = '--silence-errors'
  retval = ()
  for flag in ['--libs-only-l', '--cflags-only-I', '--libs-only-L']:
    try:
      val = subprocess.check_output([pkg_config, args, flag, pkg])
      # check_output returns bytes
      val = val.encode().strip().rstrip('\n')
    except subprocess.CalledProcessError:
      # most likely missing a .pc-file
      val = None
    except OSError:
      # no pkg-config/pkgconf installed
      return (None, None, None)
    retval += (val,)
  return retval


def try_check_compiler(cc, lang):
  try:
    proc = subprocess.Popen(shlex.split(cc) + ['-E', '-P', '-x', lang, '-'],
                            stdin=subprocess.PIPE, stdout=subprocess.PIPE)
  except OSError:
    return (False, False, '', '')

  proc.stdin.write('__clang__ __GNUC__ __GNUC_MINOR__ __GNUC_PATCHLEVEL__ '
                   '__clang_major__ __clang_minor__ __clang_patchlevel__')

  values = (proc.communicate()[0].split() + ['0'] * 7)[0:7]
  is_clang = values[0] == '1'
  gcc_version = '%s.%s.%s' % tuple(values[1:1+3])
  clang_version = '%s.%s.%s' % tuple(values[4:4+3])

  return (True, is_clang, clang_version, gcc_version)


#
# The version of asm compiler is needed for building openssl asm files.
# See deps/openssl/openssl.gypi for detail.
# Commands and reglar expressions to obtain its version number is taken from
# https://github.com/openssl/openssl/blob/OpenSSL_1_0_2-stable/crypto/sha/asm/sha512-x86_64.pl#L112-L129
#
def get_llvm_version(cc):
  try:
    proc = subprocess.Popen(shlex.split(cc) + ['-v'], stdin=subprocess.PIPE,
                            stderr=subprocess.PIPE, stdout=subprocess.PIPE)
  except OSError:
    print '''io.js configure error: No acceptable C compiler found!

        Please make sure you have a C compiler installed on your system and/or
        consider adjusting the CC environment variable if you installed
        it in a non-standard prefix.
        '''
    sys.exit()

  match = re.search(r"(^clang version|based on LLVM) ([3-9]\.[0-9]+)",
                    proc.communicate()[1])

  if match:
    return match.group(2)
  else:
    return 0


def get_gas_version(cc):
  try:
    proc = subprocess.Popen(shlex.split(cc) + ['-Wa,-v', '-c', '-o',
                                               '/dev/null', '-x',
                                               'assembler',  '/dev/null'],
                            stdin=subprocess.PIPE, stderr=subprocess.PIPE,
                            stdout=subprocess.PIPE)
  except OSError:
    print '''io.js configure error: No acceptable C compiler found!

        Please make sure you have a C compiler installed on your system and/or
        consider adjusting the CC environment variable if you installed
        it in a non-standard prefix.
        '''
    sys.exit()

  match = re.match(r"GNU assembler version ([2-9]\.[0-9]+)",
                   proc.communicate()[1])

  if match:
    return match.group(1)
  else:
    return 0

# Note: Apple clang self-reports as clang 4.2.0 and gcc 4.2.1.  It passes
# the version check more by accident than anything else but a more rigorous
# check involves checking the build number against a whitelist.  I'm not
# quite prepared to go that far yet.
def check_compiler(o):
  if sys.platform == 'win32':
    return

  ok, is_clang, clang_version, gcc_version = try_check_compiler(CXX, 'c++')
  if not ok:
    warn('failed to autodetect C++ compiler version (CXX=%s)' % CXX)
  elif clang_version < '3.4.0' if is_clang else gcc_version < '4.8.0':
    warn('C++ compiler too old, need g++ 4.8 or clang++ 3.4 (CXX=%s)' % CXX)

  ok, is_clang, clang_version, gcc_version = try_check_compiler(CC, 'c')
  if not ok:
    warn('failed to autodetect C compiler version (CC=%s)' % CC)
  elif not is_clang and gcc_version < '4.2.0':
    # clang 3.2 is a little white lie because any clang version will probably
    # do for the C bits.  However, we might as well encourage people to upgrade
    # to a version that is not completely ancient.
    warn('C compiler too old, need gcc 4.2 or clang 3.2 (CC=%s)' % CC)

    # Need llvm_version or gas_version when openssl asm files are compiled
  if options.without_ssl or options.openssl_no_asm or options.shared_openssl:
    return

  if is_clang:
    o['variables']['llvm_version'] = get_llvm_version(CC)
  else:
    o['variables']['gas_version'] = get_gas_version(CC)


def cc_macros():
  """Checks predefined macros using the CC command."""

  try:
    p = subprocess.Popen(shlex.split(CC) + ['-dM', '-E', '-'],
                         stdin=subprocess.PIPE,
                         stdout=subprocess.PIPE,
                         stderr=subprocess.PIPE)
  except OSError:
    print '''io.js configure error: No acceptable C compiler found!

        Please make sure you have a C compiler installed on your system and/or
        consider adjusting the CC environment variable if you installed
        it in a non-standard prefix.
        '''
    sys.exit()

  p.stdin.write('\n')
  out = p.communicate()[0]

  out = str(out).split('\n')

  k = {}
  for line in out:
    lst = shlex.split(line)
    if len(lst) > 2:
      key = lst[1]
      val = lst[2]
      k[key] = val
  return k


def is_arch_armv7():
  """Check for ARMv7 instructions"""
  cc_macros_cache = cc_macros()
  return ('__ARM_ARCH_7__' in cc_macros_cache or
          '__ARM_ARCH_7A__' in cc_macros_cache or
          '__ARM_ARCH_7R__' in cc_macros_cache or
          '__ARM_ARCH_7M__' in cc_macros_cache or
          '__ARM_ARCH_7S__' in cc_macros_cache)


def is_arch_armv6():
  """Check for ARMv6 instructions"""
  cc_macros_cache = cc_macros()
  return ('__ARM_ARCH_6__' in cc_macros_cache or
          '__ARM_ARCH_6M__' in cc_macros_cache)


def is_arm_hard_float_abi():
  """Check for hardfloat or softfloat eabi on ARM"""
  # GCC versions 4.6 and above define __ARM_PCS or __ARM_PCS_VFP to specify
  # the Floating Point ABI used (PCS stands for Procedure Call Standard).
  # We use these as well as a couple of other defines to statically determine
  # what FP ABI used.

  return '__ARM_PCS_VFP' in cc_macros()


def host_arch_cc():
  """Host architecture check using the CC command."""

  k = cc_macros()

  matchup = {
    '__aarch64__' : 'arm64',
    '__arm__'     : 'arm',
    '__i386__'    : 'ia32',
    '__mips__'    : 'mips',
    '__PPC64__'   : 'ppc64',
    '__PPC__'     : 'ppc',
    '__x86_64__'  : 'x64',
  }

  rtn = 'ia32' # default

  for i in matchup:
    if i in k and k[i] != '0':
      rtn = matchup[i]
      break

  return rtn


def host_arch_win():
  """Host architecture check using environ vars (better way to do this?)"""

  observed_arch = os.environ.get('PROCESSOR_ARCHITECTURE', 'x86')
  arch = os.environ.get('PROCESSOR_ARCHITEW6432', observed_arch)

  matchup = {
    'AMD64'  : 'x64',
    'x86'    : 'ia32',
    'arm'    : 'arm',
    'mips'   : 'mips',
  }

  return matchup.get(arch, 'ia32')


def configure_arm(o):
  if options.arm_float_abi:
    arm_float_abi = options.arm_float_abi
  elif is_arm_hard_float_abi():
    arm_float_abi = 'hard'
  else:
    arm_float_abi = 'default'

  if is_arch_armv7():
    o['variables']['arm_fpu'] = 'vfpv3'
    o['variables']['arm_version'] = '7'
  else:
    o['variables']['arm_fpu'] = 'vfpv2'
    o['variables']['arm_version'] = '6' if is_arch_armv6() else 'default'

  o['variables']['arm_thumb'] = 0      # -marm
  o['variables']['arm_float_abi'] = arm_float_abi

  if options.dest_os == 'android':
    o['variables']['arm_fpu'] = 'vfpv3'
    o['variables']['arm_version'] = '7'


def configure_mips(o):
  can_use_fpu_instructions = (options.mips_float_abi != 'soft')
  o['variables']['v8_can_use_fpu_instructions'] = b(can_use_fpu_instructions)
  o['variables']['v8_use_mips_abi_hardfloat'] = b(can_use_fpu_instructions)
  o['variables']['mips_arch_variant'] = options.mips_arch_variant
  o['variables']['mips_fpu_mode'] = options.mips_fpu_mode


def configure_node(o):
  if options.dest_os == 'android':
    o['variables']['OS'] = 'android'
  o['variables']['node_prefix'] = os.path.expanduser(options.prefix or '')
  o['variables']['node_install_npm'] = b(not options.without_npm)
  o['default_configuration'] = 'Debug' if options.debug else 'Release'

  host_arch = host_arch_win() if os.name == 'nt' else host_arch_cc()
  target_arch = options.dest_cpu or host_arch
  # ia32 is preferred by the build tools (GYP) over x86 even if we prefer the latter
  # the Makefile resets this to x86 afterward
  if target_arch == 'x86':
    target_arch = 'ia32'
  o['variables']['host_arch'] = host_arch
  o['variables']['target_arch'] = target_arch
  o['variables']['node_byteorder'] = sys.byteorder

  cross_compiling = target_arch != host_arch
  want_snapshots = not options.without_snapshot
  o['variables']['want_separate_host_toolset'] = int(
      cross_compiling and want_snapshots)

  if target_arch == 'arm':
    configure_arm(o)
  elif target_arch in ('mips', 'mipsel'):
    configure_mips(o)

  if flavor in ('solaris', 'mac', 'linux', 'freebsd'):
    use_dtrace = not options.without_dtrace
    # Don't enable by default on linux and freebsd
    if flavor in ('linux', 'freebsd'):
      use_dtrace = options.with_dtrace

    if flavor == 'linux':
      if options.systemtap_includes:
        o['include_dirs'] += [options.systemtap_includes]
    o['variables']['node_use_dtrace'] = b(use_dtrace)
    o['variables']['uv_use_dtrace'] = b(use_dtrace)
    o['variables']['uv_parent_path'] = '/deps/uv/'
  elif options.with_dtrace:
    raise Exception(
       'DTrace is currently only supported on SunOS, MacOS or Linux systems.')
  else:
    o['variables']['node_use_dtrace'] = 'false'

  # Enable Lttng if --with-lttng was defined. Use logic similar to
  # ETW for windows. Lttng is only available on the Linux platform.
  if flavor == 'linux':
    o['variables']['node_use_lttng'] = b(options.with_lttng)
  elif options.with_lttng:
    raise Exception('lttng is only supported on Linux.')
  else:
    o['variables']['node_use_lttng'] = 'false'

  if options.no_ifaddrs:
    o['defines'] += ['SUNOS_NO_IFADDRS']

  # By default, enable ETW on Windows.
  if flavor == 'win':
    o['variables']['node_use_etw'] = b(not options.without_etw)
  elif options.with_etw:
    raise Exception('ETW is only supported on Windows.')
  else:
    o['variables']['node_use_etw'] = 'false'

  # By default, enable Performance counters on Windows.
  if flavor == 'win':
    o['variables']['node_use_perfctr'] = b(not options.without_perfctr)
  elif options.with_perfctr:
    raise Exception('Performance counter is only supported on Windows.')
  else:
    o['variables']['node_use_perfctr'] = 'false'

  if options.tag:
    o['variables']['node_tag'] = '-' + options.tag
  else:
    o['variables']['node_tag'] = ''

  o['variables']['node_release_urlbase'] = options.release_urlbase or ''

  if options.v8_options:
    o['variables']['node_v8_options'] = options.v8_options.replace('"', '\\"')

  if options.enable_static:
    o['variables']['node_target_type'] = 'static_library'


def configure_library(lib, output):
  shared_lib = 'shared_' + lib
  output['variables']['node_' + shared_lib] = b(getattr(options, shared_lib))

  if getattr(options, shared_lib):
    (pkg_libs, pkg_cflags, pkg_libpath) = pkg_config(lib)

    if pkg_cflags:
      output['include_dirs'] += (
          filter(None, map(str.strip, pkg_cflags.split('-I'))))

    # libpath needs to be provided ahead libraries
    if pkg_libpath:
      output['libraries'] += (
          filter(None, map(str.strip, pkg_cflags.split('-L'))))

    default_libs = getattr(options, shared_lib + '_libname')
    default_libs = map('-l{0}'.format, default_libs.split(','))

    if pkg_libs:
      output['libraries'] += pkg_libs.split()
    elif default_libs:
      output['libraries'] += default_libs


def configure_v8(o):
  o['variables']['v8_enable_gdbjit'] = 1 if options.gdb else 0
  o['variables']['v8_no_strict_aliasing'] = 1  # Work around compiler bugs.
  o['variables']['v8_optimized_debug'] = 0  # Compile with -O0 in debug builds.
  o['variables']['v8_random_seed'] = 0  # Use a random seed for hash tables.
  o['variables']['v8_use_snapshot'] = 0 if options.without_snapshot else 1

def configure_openssl(o):
  o['variables']['node_use_openssl'] = b(not options.without_ssl)
  o['variables']['node_shared_openssl'] = b(options.shared_openssl)
  o['variables']['openssl_no_asm'] = 1 if options.openssl_no_asm else 0
  if options.openssl_fips:
    o['variables']['openssl_fips'] = options.openssl_fips
    fips_dir = os.path.join(root_dir, 'deps', 'openssl', 'fips')
    fips_ld = os.path.abspath(os.path.join(fips_dir, 'fipsld'))
    o['make_global_settings'] = [
      ['LINK', fips_ld + ' <(openssl_fips)/bin/fipsld'],
    ]
  else:
    o['variables']['openssl_fips'] = ''


  if options.without_ssl:
    return
  configure_library('openssl', o)


def configure_fullystatic(o):
  if options.fully_static:
    o['libraries'] += ['-static']
    if flavor == 'mac':
      print("Generation of static executable will not work on OSX "
            "when using default compilation environment")


def configure_winsdk(o):
  if flavor != 'win':
    return

  winsdk_dir = os.environ.get('WindowsSdkDir')

  if winsdk_dir and os.path.isfile(winsdk_dir + '\\bin\\ctrpp.exe'):
    print('Found ctrpp in WinSDK--will build generated files '
          'into tools/msvs/genfiles.')
    o['variables']['node_has_winsdk'] = 'true'
    return

  print('ctrpp not found in WinSDK path--using pre-gen files '
        'from tools/msvs/genfiles.')

def write(filename, data):
  filename = os.path.join(root_dir, filename)
  print 'creating ', filename
  f = open(filename, 'w+')
  f.write(data)

do_not_edit = '# Do not edit. Generated by the configure script.\n'

def glob_to_var(dir_base, dir_sub):
  list = []
  dir_all = os.path.join(dir_base, dir_sub)
  files = os.walk(dir_all)
  for ent in files:
    (path, dirs, files) = ent
    for file in files:
      if file.endswith('.cpp') or file.endswith('.c') or file.endswith('.h'):
        list.append('%s/%s' % (dir_sub, file))
    break
  return list

def configure_intl(o):
  icus = [
    {
      'url': 'http://download.icu-project.org/files/icu4c/54.1/icu4c-54_1-src.zip',
      # from https://ssl.icu-project.org/files/icu4c/54.1/icu4c-src-54_1.md5:
      'md5': '6b89d60e2f0e140898ae4d7f72323bca',
    },
  ]
  def icu_download(path):
    # download ICU, if needed
    for icu in icus:
      url = icu['url']
      md5 = icu['md5']
      local = url.split('/')[-1]
      targetfile = os.path.join(root_dir, 'deps', local)
      if not os.path.isfile(targetfile):
        if nodedownload.candownload(auto_downloads, "icu"):
          nodedownload.retrievefile(url, targetfile)
      else:
        print ' Re-using existing %s' % targetfile
      if os.path.isfile(targetfile):
        sys.stdout.write(' Checking file integrity with MD5:\r')
        gotmd5 = nodedownload.md5sum(targetfile)
        print ' MD5:      %s  %s' % (gotmd5, targetfile)
        if (md5 == gotmd5):
          return targetfile
        else:
          print ' Expected: %s      *MISMATCH*' % md5
          print '\n ** Corrupted ZIP? Delete %s to retry download.\n' % targetfile
    return None
  icu_config = {
    'variables': {}
  }
  icu_config_name = 'icu_config.gypi'
  def write_config(data, name):
    return

  # write an empty file to start with
  write(icu_config_name, do_not_edit +
        pprint.pformat(icu_config, indent=2) + '\n')

  # always set icu_small, node.gyp depends on it being defined.
  o['variables']['icu_small'] = b(False)

  with_intl = options.with_intl
  with_icu_source = options.with_icu_source
  have_icu_path = bool(options.with_icu_path)
  if have_icu_path and with_intl != 'none':
    print 'Error: Cannot specify both --with-icu-path and --with-intl'
    sys.exit(1)
  elif have_icu_path:
    # Chromium .gyp mode: --with-icu-path
    o['variables']['v8_enable_i18n_support'] = 1
    # use the .gyp given
    o['variables']['icu_gyp_path'] = options.with_icu_path
    return
  # --with-intl=<with_intl>
  # set the default
  if with_intl in (None, 'none'):
    o['variables']['v8_enable_i18n_support'] = 0
    return  # no Intl
  elif with_intl == 'small-icu':
    # small ICU (English only)
    o['variables']['v8_enable_i18n_support'] = 1
    o['variables']['icu_small'] = b(True)
    locs = set(options.with_icu_locales.split(','))
    locs.add('root')  # must have root
    o['variables']['icu_locales'] = string.join(locs,',')
  elif with_intl == 'full-icu':
    # full ICU
    o['variables']['v8_enable_i18n_support'] = 1
  elif with_intl == 'system-icu':
    # ICU from pkg-config.
    o['variables']['v8_enable_i18n_support'] = 1
    pkgicu = pkg_config('icu-i18n')
    if pkgicu[0] is None:
      print 'Error: could not load pkg-config data for "icu-i18n".'
      print 'See above errors or the README.md.'
      sys.exit(1)
    (libs, cflags, libpath) = pkgicu
    # libpath provides linker path which may contain spaces
    if libpath:
      o['libraries'] += [libpath]
    # safe to split, cannot contain spaces
    o['libraries'] += libs.split()
    if cflags:
      o['include_dirs'] += filter(None, map(str.strip, cflags.split('-I')))
    # use the "system" .gyp
    o['variables']['icu_gyp_path'] = 'tools/icu/icu-system.gyp'
    return

  # this is just the 'deps' dir. Used for unpacking.
  icu_parent_path = os.path.join(root_dir, 'deps')

  # The full path to the ICU source directory.
  icu_full_path = os.path.join(icu_parent_path, 'icu')

  # icu-tmp is used to download and unpack the ICU tarball.
  icu_tmp_path = os.path.join(icu_parent_path, 'icu-tmp')

  # --with-icu-source processing
  # first, check that they didn't pass --with-icu-source=deps/icu
  if with_icu_source and os.path.abspath(icu_full_path) == os.path.abspath(with_icu_source):
    print 'Ignoring redundant --with-icu-source=%s' % (with_icu_source)
    with_icu_source = None
  # if with_icu_source is still set, try to use it.
  if with_icu_source:
    if os.path.isdir(icu_full_path):
      print 'Deleting old ICU source: %s' % (icu_full_path)
      shutil.rmtree(icu_full_path)
    # now, what path was given?
    if os.path.isdir(with_icu_source):
      # it's a path. Copy it.
      print '%s -> %s' % (with_icu_source, icu_full_path)
      shutil.copytree(with_icu_source, icu_full_path)
    else:
      # could be file or URL.
      # Set up temporary area
      if os.path.isdir(icu_tmp_path):
        shutil.rmtree(icu_tmp_path)
      os.mkdir(icu_tmp_path)
      icu_tarball = None
      if os.path.isfile(with_icu_source):
        # it's a file. Try to unpack it.
        icu_tarball = with_icu_source
      else:
        # Can we download it?
        local = os.path.join(icu_tmp_path, with_icu_source.split('/')[-1])  # local part
        icu_tarball = nodedownload.retrievefile(with_icu_source, local)
      # continue with "icu_tarball"
      nodedownload.unpack(icu_tarball, icu_tmp_path)
      # Did it unpack correctly? Should contain 'icu'
      tmp_icu = os.path.join(icu_tmp_path, 'icu')
      if os.path.isdir(tmp_icu):
        os.rename(tmp_icu, icu_full_path)
        shutil.rmtree(icu_tmp_path)
      else:
        print ' Error: --with-icu-source=%s did not result in an "icu" dir.' % with_icu_source
        shutil.rmtree(icu_tmp_path)
        sys.exit(1)

  # ICU mode. (icu-generic.gyp)
  o['variables']['icu_gyp_path'] = 'tools/icu/icu-generic.gyp'
  # ICU source dir relative to root
  o['variables']['icu_path'] = icu_full_path
  if not os.path.isdir(icu_full_path):
    print '* ECMA-402 (Intl) support didn\'t find ICU in %s..' % (icu_full_path)
    # can we download (or find) a zipfile?
    localzip = icu_download(icu_full_path)
    if localzip:
      nodedownload.unpack(localzip, icu_parent_path)
  if not os.path.isdir(icu_full_path):
    print ' Cannot build Intl without ICU in %s.' % (icu_full_path)
    print ' (Fix, or disable with "--with-intl=none" )'
    sys.exit(1)
  else:
    print '* Using ICU in %s' % (icu_full_path)
  # Now, what version of ICU is it? We just need the "major", such as 54.
  # uvernum.h contains it as a #define.
  uvernum_h = os.path.join(icu_full_path, 'source/common/unicode/uvernum.h')
  if not os.path.isfile(uvernum_h):
    print ' Error: could not load %s - is ICU installed?' % uvernum_h
    sys.exit(1)
  icu_ver_major = None
  matchVerExp = r'^\s*#define\s+U_ICU_VERSION_SHORT\s+"([^"]*)".*'
  match_version = re.compile(matchVerExp)
  for line in open(uvernum_h).readlines():
    m = match_version.match(line)
    if m:
      icu_ver_major = m.group(1)
  if not icu_ver_major:
    print ' Could not read U_ICU_VERSION_SHORT version from %s' % uvernum_h
    sys.exit(1)
  icu_endianness = sys.byteorder[0];  # TODO(srl295): EBCDIC should be 'e'
  o['variables']['icu_ver_major'] = icu_ver_major
  o['variables']['icu_endianness'] = icu_endianness
  icu_data_file_l = 'icudt%s%s.dat' % (icu_ver_major, 'l')
  icu_data_file = 'icudt%s%s.dat' % (icu_ver_major, icu_endianness)
  # relative to configure
  icu_data_path = os.path.join(icu_full_path,
                               'source/data/in',
                               icu_data_file_l)
  # relative to dep..
  icu_data_in = os.path.join('../../deps/icu/source/data/in', icu_data_file_l)
  if not os.path.isfile(icu_data_path) and icu_endianness != 'l':
    # use host endianness
    icu_data_path = os.path.join(icu_full_path,
                                 'source/data/in',
                                 icu_data_file)
    # relative to dep..
    icu_data_in = os.path.join('icu/source/data/in',
                               icu_data_file)
  # this is the input '.dat' file to use .. icudt*.dat
  # may be little-endian if from a icu-project.org tarball
  o['variables']['icu_data_in'] = icu_data_in
  # this is the icudt*.dat file which node will be using (platform endianness)
  o['variables']['icu_data_file'] = icu_data_file
  if not os.path.isfile(icu_data_path):
    print ' Error: ICU prebuilt data file %s does not exist.' % icu_data_path
    print ' See the README.md.'
    # .. and we're not about to build it from .gyp!
    sys.exit(1)
  # map from variable name to subdirs
  icu_src = {
    'stubdata': 'stubdata',
    'common': 'common',
    'i18n': 'i18n',
    'io': 'io',
    'tools': 'tools/toolutil',
    'genccode': 'tools/genccode',
    'genrb': 'tools/genrb',
    'icupkg': 'tools/icupkg',
  }
  # this creates a variable icu_src_XXX for each of the subdirs
  # with a list of the src files to use
  for i in icu_src:
    var  = 'icu_src_%s' % i
    path = '../../deps/icu/source/%s' % icu_src[i]
    icu_config['variables'][var] = glob_to_var('tools/icu', path)
  # write updated icu_config.gypi with a bunch of paths
  write(icu_config_name, do_not_edit +
        pprint.pformat(icu_config, indent=2) + '\n')
  return  # end of configure_intl

output = {
  'variables': { 'python': sys.executable },
  'include_dirs': [],
  'libraries': [],
  'defines': [],
  'cflags': [],
}

# Print a warning when the compiler is too old.
check_compiler(output)

# determine the "flavor" (operating system) we're building for,
# leveraging gyp's GetFlavor function
flavor_params = {}
if (options.dest_os):
  flavor_params['flavor'] = options.dest_os
flavor = GetFlavor(flavor_params)

configure_node(output)
configure_library('zlib', output)
configure_library('http_parser', output)
configure_library('libuv', output)
configure_v8(output)
configure_openssl(output)
configure_winsdk(output)
configure_intl(output)
configure_fullystatic(output)

# variables should be a root level element,
# move everything else to target_defaults
variables = output['variables']
del output['variables']

# make_global_settings should be a root level element too
if 'make_global_settings' in output:
  make_global_settings = output['make_global_settings']
  del output['make_global_settings']
else:
  make_global_settings = False

output = {
  'variables': variables,
  'target_defaults': output,
}
if make_global_settings:
  output['make_global_settings'] = make_global_settings

pprint.pprint(output, indent=2)

write('config.gypi', do_not_edit +
      pprint.pformat(output, indent=2) + '\n')

config = {
  'BUILDTYPE': 'Debug' if options.debug else 'Release',
  'USE_XCODE': str(int(options.use_xcode or 0)),
  'PYTHON': sys.executable,
}

if options.prefix:
  config['PREFIX'] = options.prefix

config = '\n'.join(map('='.join, config.iteritems())) + '\n'

write('config.mk',
      '# Do not edit. Generated by the configure script.\n' + config)

gyp_args = [sys.executable, 'tools/gyp_node.py', '--no-parallel']

if options.use_xcode:
  gyp_args += ['-f', 'xcode']
elif flavor == 'win' and sys.platform != 'msys':
  gyp_args += ['-f', 'msvs', '-G', 'msvs_version=auto']
else:
  gyp_args += ['-f', 'make-' + flavor]

gyp_args += args

if warn.warned:
  warn('warnings were emitted in the configure phase')

sys.exit(subprocess.call(gyp_args))