#!/usr/bin/env python
# Copyright 2014 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.

"""Generates build.ninja that will build GN."""

import contextlib
import errno
import optparse
import os
import platform
import re
import subprocess
import sys
import tempfile

SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))
REPO_ROOT = os.path.dirname(SCRIPT_DIR)
GN_ROOT = os.path.join(REPO_ROOT, 'tools', 'gn')


class Platform(object):
  """Represents a host/target platform."""
  def __init__(self, platform):
    self._platform = platform
    if self._platform is not None:
      return
    self._platform = sys.platform
    if self._platform.startswith('linux'):
      self._platform = 'linux'
    elif self._platform.startswith('darwin'):
      self._platform = 'darwin'
    elif self._platform.startswith('mingw'):
      self._platform = 'mingw'
    elif self._platform.startswith('win'):
      self._platform = 'msvc'
    elif self._platform.startswith('aix'):
      self._platform = 'aix'
    elif self._platform.startswith('fuchsia'):
      self._platform = 'fuchsia'

  @staticmethod
  def known_platforms():
    return ['linux', 'darwin', 'msvc', 'aix', 'fuchsia']

  def platform(self):
    return self._platform

  def is_linux(self):
    return self._platform == 'linux'

  def is_mingw(self):
    return self._platform == 'mingw'

  def is_msvc(self):
    return self._platform == 'msvc'

  def is_windows(self):
    return self.is_mingw() or self.is_msvc()

  def is_darwin(self):
    return self._platform == 'darwin'

  def is_aix(self):
    return self._platform == 'aix'

  def is_posix(self):
    return self._platform in ['linux', 'darwin', 'aix']


def main(argv):
  parser = optparse.OptionParser(description=sys.modules[__name__].__doc__)
  parser.add_option('-d', '--debug', action='store_true',
                    help='Do a debug build. Defaults to release build.')
  parser.add_option('--platform',
                    help='target platform (' +
                         '/'.join(Platform.known_platforms()) + ')',
                    choices=Platform.known_platforms())
  parser.add_option('--host',
                    help='host platform (' +
                         '/'.join(Platform.known_platforms()) + ')',
                    choices=Platform.known_platforms())
  parser.add_option('--use-lto', action='store_true',
                    help='Enable the use of LTO')
  parser.add_option('--use-icf', action='store_true',
                    help='Enable the use of Identical Code Folding')
  parser.add_option('--no-last-commit-position', action='store_true',
                    help='Do not generate last_commit_position.h.')
  parser.add_option('--out-path',
                    help='The path to generate the build files in.')
  options, args = parser.parse_args(argv)

  if args:
    parser.error('Unrecognized command line arguments: %s.' % ', '.join(args))

  platform = Platform(options.platform)
  if options.host:
    host = Platform(options.host)
  else:
    host = platform

  out_dir = options.out_path or os.path.join(REPO_ROOT, 'out')
  if not os.path.isdir(out_dir):
    os.makedirs(out_dir)
  if not options.no_last_commit_position:
    GenerateLastCommitPosition(host,
                               os.path.join(out_dir, 'last_commit_position.h'))
  WriteGNNinja(os.path.join(out_dir, 'build.ninja'), platform, host, options)
  return 0


def GenerateLastCommitPosition(host, header):
  ROOT_TAG = 'initial-commit'
  describe_output = subprocess.check_output(
      ['git', 'describe', 'HEAD', '--match', ROOT_TAG], shell=host.is_windows(),
      cwd=REPO_ROOT)
  mo = re.match(ROOT_TAG + '-(\d+)-g([0-9a-f]+)', describe_output)
  if not mo:
    raise ValueError(
        'Unexpected output from git describe when generating version header')

  contents = '''// Generated by build/gen.py.

#ifndef OUT_LAST_COMMIT_POSITION_H_
#define OUT_LAST_COMMIT_POSITION_H_

#define LAST_COMMIT_POSITION "%s (%s)"

#endif  // OUT_LAST_COMMIT_POSITION_H_
''' % (mo.group(1), mo.group(2))

  # Only write/touch this file if the commit position has changed.
  old_contents = ''
  if os.path.isfile(header):
    with open(header, 'rb') as f:
      old_contents = f.read()

  if old_contents != contents:
    with open(header, 'wb') as f:
      f.write(contents)


def WriteGenericNinja(path, static_libraries, executables,
                      cc, cxx, ar, ld, platform, host, options,
                      cflags=[], cflags_cc=[], ldflags=[], libflags=[],
                      include_dirs=[], solibs=[]):
  ninja_header_lines = [
    'cc = ' + cc,
    'cxx = ' + cxx,
    'ar = ' + ar,
    'ld = ' + ld,
    '',
    'rule regen',
    '  command = %s ../build/gen.py%s' % (
        sys.executable, ' -d' if options.debug else ''),
    '  description = Regenerating ninja files',
    '',
    'build build.ninja: regen',
    '  generator = 1',
    '  depfile = build.ninja.d',
    '',
  ]


  template_filename = os.path.join(SCRIPT_DIR, {
      'msvc': 'build_win.ninja.template',
      'darwin': 'build_mac.ninja.template',
      'linux': 'build_linux.ninja.template',
      'aix': 'build_aix.ninja.template',
  }[platform.platform()])

  with open(template_filename) as f:
    ninja_template = f.read()

  if platform.is_windows():
    executable_ext = '.exe'
    library_ext = '.lib'
    object_ext = '.obj'
  else:
    executable_ext = ''
    library_ext = '.a'
    object_ext = '.o'

  def escape_path_ninja(path):
      return path.replace('$ ', '$$ ').replace(' ', '$ ').replace(':', '$:')

  def src_to_obj(path):
    return escape_path_ninja('%s' % os.path.splitext(path)[0] + object_ext)

  def library_to_a(library):
    return '%s%s' % (library, library_ext)

  ninja_lines = []
  def build_source(src_file, settings):
    ninja_lines.extend([
        'build %s: %s %s' % (src_to_obj(src_file),
                             settings['tool'],
                             escape_path_ninja(
                                 os.path.join(REPO_ROOT, src_file))),
        '  includes = %s' % ' '.join(
            ['-I' + escape_path_ninja(dirname) for dirname in
             include_dirs + settings.get('include_dirs', [])]),
        '  cflags = %s' % ' '.join(cflags + settings.get('cflags', [])),
        '  cflags_cc = %s' %
            ' '.join(cflags_cc + settings.get('cflags_cc', [])),
    ])

  for library, settings in static_libraries.iteritems():
    for src_file in settings['sources']:
      build_source(src_file, settings)

    ninja_lines.append('build %s: alink_thin %s' % (
        library_to_a(library),
        ' '.join([src_to_obj(src_file) for src_file in settings['sources']])))
    ninja_lines.append('  libflags = %s' % ' '.join(libflags))


  for executable, settings in executables.iteritems():
    for src_file in settings['sources']:
      build_source(src_file, settings)

    ninja_lines.extend([
      'build %s%s: link %s | %s' % (
          executable, executable_ext,
          ' '.join([src_to_obj(src_file) for src_file in settings['sources']]),
          ' '.join([library_to_a(library) for library in settings['libs']])),
      '  ldflags = %s' % ' '.join(ldflags),
      '  solibs = %s' % ' '.join(solibs),
      '  libs = %s' % ' '.join(
          [library_to_a(library) for library in settings['libs']]),
    ])

  ninja_lines.append('')  # Make sure the file ends with a newline.

  with open(path, 'w') as f:
    f.write('\n'.join(ninja_header_lines))
    f.write(ninja_template)
    f.write('\n'.join(ninja_lines))

  with open(path + '.d', 'w') as f:
    f.write('build.ninja: ' +
            os.path.relpath(os.path.join(SCRIPT_DIR, 'gen.py'),
                            os.path.dirname(path)) + ' ' +
            os.path.relpath(template_filename, os.path.dirname(path)) + '\n')


def WriteGNNinja(path, platform, host, options):
  if platform.is_msvc():
    cc = os.environ.get('CC', 'cl.exe')
    cxx = os.environ.get('CXX', 'cl.exe')
    ld = os.environ.get('LD', 'link.exe')
    ar = os.environ.get('AR', 'lib.exe')
  elif platform.is_aix():
    cc = os.environ.get('CC', 'gcc')
    cxx = os.environ.get('CXX', 'g++')
    ld = os.environ.get('LD', 'g++')
    ar = os.environ.get('AR', 'ar -X64')
  else:
    cc = os.environ.get('CC', 'clang')
    cxx = os.environ.get('CXX', 'clang++')
    ld = cxx
    ar = os.environ.get('AR', 'ar')

  cflags = os.environ.get('CFLAGS', '').split()
  cflags_cc = os.environ.get('CXXFLAGS', '').split()
  ldflags = os.environ.get('LDFLAGS', '').split()
  libflags = os.environ.get('LIBFLAGS', '').split()
  include_dirs = [REPO_ROOT, os.path.dirname(path)]
  libs = []

  if not platform.is_msvc():
    if options.debug:
      cflags.extend(['-O0', '-g'])
    else:
      cflags.append('-DNDEBUG')
      cflags.append('-O3')
      ldflags.append('-O3')
      # Use -fdata-sections and -ffunction-sections to place each function
      # or data item into its own section so --gc-sections can eliminate any
      # unused functions and data items.
      cflags.extend(['-fdata-sections', '-ffunction-sections'])
      ldflags.extend(['-fdata-sections', '-ffunction-sections'])
      if platform.is_darwin():
        ldflags.append('-Wl,-dead_strip')
      elif not platform.is_aix():
        # Garbage collection is done by default on aix.
        ldflags.append('-Wl,--gc-sections')

      # Omit all symbol information from the output file.
      if platform.is_darwin():
        ldflags.append('-Wl,-S')
      elif platform.is_aix():
        ldflags.append('-Wl,-s')
      else:
        ldflags.append('-Wl,-strip-all')

      # Enable identical code-folding.
      if options.use_icf:
        ldflags.append('-Wl,--icf=all')

    cflags.extend([
        '-D_FILE_OFFSET_BITS=64',
        '-D__STDC_CONSTANT_MACROS', '-D__STDC_FORMAT_MACROS',
        '-pthread',
        '-pipe',
        '-fno-exceptions',
        '-fno-rtti',
        '-fdiagnostics-color',
    ])
    cflags_cc.extend(['-std=c++14', '-Wno-c++11-narrowing'])

    if platform.is_linux():
      ldflags.extend([
          '-static-libstdc++',
          '-Wl,--as-needed',
      ])
      libs.extend([
          # These are needed by libc++.
          '-ldl',
          '-lpthread',
      ])
    elif platform.is_darwin():
      min_mac_version_flag = '-mmacosx-version-min=10.9'
      cflags.append(min_mac_version_flag)
      ldflags.append(min_mac_version_flag)
    elif platform.is_aix():
      cflags_cc.append('-maix64')
      ldflags.extend(['-maix64', '-pthread'])

    if options.use_lto:
      cflags.extend(['-flto', '-fwhole-program-vtables'])
      ldflags.extend(['-flto', '-fwhole-program-vtables'])

  elif platform.is_msvc():
    if not options.debug:
      cflags.extend(['/O2', '/DNDEBUG', '/GL'])
      libflags.extend(['/LTCG'])
      ldflags.extend(['/LTCG', '/OPT:REF', '/OPT:ICF'])

    cflags.extend([
        '/DNOMINMAX',
        '/DUNICODE',
        '/DWIN32_LEAN_AND_MEAN',
        '/DWINVER=0x0A00',
        '/D_CRT_SECURE_NO_DEPRECATE',
        '/D_SCL_SECURE_NO_DEPRECATE',
        '/D_UNICODE',
        '/D_WIN32_WINNT=0x0A00',
        '/FS',
        '/W4',
        '/WX',
        '/Zi',
        '/wd4099',
        '/wd4100',
        '/wd4127',
        '/wd4244',
        '/wd4267',
        '/wd4838',
        '/wd4996',
    ])
    cflags_cc.extend([
        '/GR-',
        '/D_HAS_EXCEPTIONS=0',
    ])

    ldflags.extend(['/DEBUG', '/MACHINE:x64'])

  static_libraries = {
      'base': {'sources': [
        'base/callback_internal.cc',
        'base/command_line.cc',
        'base/environment.cc',
        'base/files/file.cc',
        'base/files/file_enumerator.cc',
        'base/files/file_path.cc',
        'base/files/file_path_constants.cc',
        'base/files/file_util.cc',
        'base/files/scoped_file.cc',
        'base/files/scoped_temp_dir.cc',
        'base/json/json_parser.cc',
        'base/json/json_reader.cc',
        'base/json/json_writer.cc',
        'base/json/string_escape.cc',
        'base/logging.cc',
        'base/md5.cc',
        'base/memory/ref_counted.cc',
        'base/memory/weak_ptr.cc',
        'base/sha1.cc',
        'base/strings/string_number_conversions.cc',
        'base/strings/string_piece.cc',
        'base/strings/string_split.cc',
        'base/strings/string_util.cc',
        'base/strings/string_util_constants.cc',
        'base/strings/stringprintf.cc',
        'base/strings/utf_string_conversion_utils.cc',
        'base/strings/utf_string_conversions.cc',
        'base/third_party/icu/icu_utf.cc',
        'base/timer/elapsed_timer.cc',
        'base/value_iterators.cc',
        'base/values.cc',
      ], 'tool': 'cxx', 'include_dirs': []},
      'gn_lib': {'sources': [
        'tools/gn/action_target_generator.cc',
        'tools/gn/action_values.cc',
        'tools/gn/analyzer.cc',
        'tools/gn/args.cc',
        'tools/gn/binary_target_generator.cc',
        'tools/gn/builder.cc',
        'tools/gn/builder_record.cc',
        'tools/gn/build_settings.cc',
        'tools/gn/bundle_data.cc',
        'tools/gn/bundle_data_target_generator.cc',
        'tools/gn/bundle_file_rule.cc',
        'tools/gn/c_include_iterator.cc',
        'tools/gn/command_analyze.cc',
        'tools/gn/command_args.cc',
        'tools/gn/command_check.cc',
        'tools/gn/command_clean.cc',
        'tools/gn/command_desc.cc',
        'tools/gn/command_format.cc',
        'tools/gn/command_gen.cc',
        'tools/gn/command_help.cc',
        'tools/gn/command_ls.cc',
        'tools/gn/command_path.cc',
        'tools/gn/command_refs.cc',
        'tools/gn/commands.cc',
        'tools/gn/compile_commands_writer.cc',
        'tools/gn/config.cc',
        'tools/gn/config_values.cc',
        'tools/gn/config_values_extractors.cc',
        'tools/gn/config_values_generator.cc',
        'tools/gn/copy_target_generator.cc',
        'tools/gn/create_bundle_target_generator.cc',
        'tools/gn/deps_iterator.cc',
        'tools/gn/desc_builder.cc',
        'tools/gn/eclipse_writer.cc',
        'tools/gn/err.cc',
        'tools/gn/escape.cc',
        'tools/gn/exec_process.cc',
        'tools/gn/filesystem_utils.cc',
        'tools/gn/function_exec_script.cc',
        'tools/gn/function_foreach.cc',
        'tools/gn/function_forward_variables_from.cc',
        'tools/gn/function_get_label_info.cc',
        'tools/gn/function_get_path_info.cc',
        'tools/gn/function_get_target_outputs.cc',
        'tools/gn/function_process_file_template.cc',
        'tools/gn/function_read_file.cc',
        'tools/gn/function_rebase_path.cc',
        'tools/gn/functions.cc',
        'tools/gn/function_set_defaults.cc',
        'tools/gn/function_set_default_toolchain.cc',
        'tools/gn/functions_target.cc',
        'tools/gn/function_template.cc',
        'tools/gn/function_toolchain.cc',
        'tools/gn/function_write_file.cc',
        'tools/gn/group_target_generator.cc',
        'tools/gn/header_checker.cc',
        'tools/gn/import_manager.cc',
        'tools/gn/inherited_libraries.cc',
        'tools/gn/input_conversion.cc',
        'tools/gn/input_file.cc',
        'tools/gn/input_file_manager.cc',
        'tools/gn/item.cc',
        'tools/gn/json_project_writer.cc',
        'tools/gn/label.cc',
        'tools/gn/label_pattern.cc',
        'tools/gn/lib_file.cc',
        'tools/gn/loader.cc',
        'tools/gn/location.cc',
        'tools/gn/ninja_action_target_writer.cc',
        'tools/gn/ninja_binary_target_writer.cc',
        'tools/gn/ninja_build_writer.cc',
        'tools/gn/ninja_bundle_data_target_writer.cc',
        'tools/gn/ninja_copy_target_writer.cc',
        'tools/gn/ninja_create_bundle_target_writer.cc',
        'tools/gn/ninja_group_target_writer.cc',
        'tools/gn/ninja_target_command_util.cc',
        'tools/gn/ninja_target_writer.cc',
        'tools/gn/ninja_toolchain_writer.cc',
        'tools/gn/ninja_utils.cc',
        'tools/gn/ninja_writer.cc',
        'tools/gn/operators.cc',
        'tools/gn/output_conversion.cc',
        'tools/gn/output_file.cc',
        'tools/gn/parse_node_value_adapter.cc',
        'tools/gn/parser.cc',
        'tools/gn/parse_tree.cc',
        'tools/gn/path_output.cc',
        'tools/gn/pattern.cc',
        'tools/gn/pool.cc',
        'tools/gn/qt_creator_writer.cc',
        'tools/gn/runtime_deps.cc',
        'tools/gn/scheduler.cc',
        'tools/gn/scope.cc',
        'tools/gn/scope_per_file_provider.cc',
        'tools/gn/settings.cc',
        'tools/gn/setup.cc',
        'tools/gn/source_dir.cc',
        'tools/gn/source_file.cc',
        'tools/gn/source_file_type.cc',
        'tools/gn/standard_out.cc',
        'tools/gn/string_utils.cc',
        'tools/gn/substitution_list.cc',
        'tools/gn/substitution_pattern.cc',
        'tools/gn/substitution_type.cc',
        'tools/gn/substitution_writer.cc',
        'tools/gn/switches.cc',
        'tools/gn/target.cc',
        'tools/gn/target_generator.cc',
        'tools/gn/template.cc',
        'tools/gn/token.cc',
        'tools/gn/tokenizer.cc',
        'tools/gn/tool.cc',
        'tools/gn/toolchain.cc',
        'tools/gn/trace.cc',
        'tools/gn/value.cc',
        'tools/gn/value_extractors.cc',
        'tools/gn/variables.cc',
        'tools/gn/visibility.cc',
        'tools/gn/visual_studio_utils.cc',
        'tools/gn/visual_studio_writer.cc',
        'tools/gn/xcode_object.cc',
        'tools/gn/xcode_writer.cc',
        'tools/gn/xml_element_writer.cc',
        'util/exe_path.cc',
        'util/msg_loop.cc',
        'util/semaphore.cc',
        'util/sys_info.cc',
        'util/ticks.cc',
        'util/worker_pool.cc',
      ], 'tool': 'cxx', 'include_dirs': []},
  }

  executables = {
      'gn': {'sources': [ 'tools/gn/gn_main.cc' ],
      'tool': 'cxx', 'include_dirs': [], 'libs': []},

      'gn_unittests': { 'sources': [
        'tools/gn/action_target_generator_unittest.cc',
        'tools/gn/analyzer_unittest.cc',
        'tools/gn/args_unittest.cc',
        'tools/gn/builder_unittest.cc',
        'tools/gn/c_include_iterator_unittest.cc',
        'tools/gn/command_format_unittest.cc',
        'tools/gn/compile_commands_writer_unittest.cc',
        'tools/gn/config_unittest.cc',
        'tools/gn/config_values_extractors_unittest.cc',
        'tools/gn/escape_unittest.cc',
        'tools/gn/exec_process_unittest.cc',
        'tools/gn/filesystem_utils_unittest.cc',
        'tools/gn/function_foreach_unittest.cc',
        'tools/gn/function_forward_variables_from_unittest.cc',
        'tools/gn/function_get_label_info_unittest.cc',
        'tools/gn/function_get_path_info_unittest.cc',
        'tools/gn/function_get_target_outputs_unittest.cc',
        'tools/gn/function_process_file_template_unittest.cc',
        'tools/gn/function_rebase_path_unittest.cc',
        'tools/gn/function_template_unittest.cc',
        'tools/gn/function_toolchain_unittest.cc',
        'tools/gn/function_write_file_unittest.cc',
        'tools/gn/functions_target_unittest.cc',
        'tools/gn/functions_unittest.cc',
        'tools/gn/header_checker_unittest.cc',
        'tools/gn/inherited_libraries_unittest.cc',
        'tools/gn/input_conversion_unittest.cc',
        'tools/gn/label_pattern_unittest.cc',
        'tools/gn/label_unittest.cc',
        'tools/gn/loader_unittest.cc',
        'tools/gn/ninja_action_target_writer_unittest.cc',
        'tools/gn/ninja_binary_target_writer_unittest.cc',
        'tools/gn/ninja_build_writer_unittest.cc',
        'tools/gn/ninja_bundle_data_target_writer_unittest.cc',
        'tools/gn/ninja_copy_target_writer_unittest.cc',
        'tools/gn/ninja_create_bundle_target_writer_unittest.cc',
        'tools/gn/ninja_group_target_writer_unittest.cc',
        'tools/gn/ninja_target_writer_unittest.cc',
        'tools/gn/ninja_toolchain_writer_unittest.cc',
        'tools/gn/operators_unittest.cc',
        'tools/gn/output_conversion_unittest.cc',
        'tools/gn/parse_tree_unittest.cc',
        'tools/gn/parser_unittest.cc',
        'tools/gn/path_output_unittest.cc',
        'tools/gn/pattern_unittest.cc',
        'tools/gn/runtime_deps_unittest.cc',
        'tools/gn/scope_per_file_provider_unittest.cc',
        'tools/gn/scope_unittest.cc',
        'tools/gn/source_dir_unittest.cc',
        'tools/gn/source_file_unittest.cc',
        'tools/gn/string_utils_unittest.cc',
        'tools/gn/substitution_pattern_unittest.cc',
        'tools/gn/substitution_writer_unittest.cc',
        'tools/gn/target_unittest.cc',
        'tools/gn/template_unittest.cc',
        'tools/gn/test_with_scheduler.cc',
        'tools/gn/test_with_scope.cc',
        'tools/gn/tokenizer_unittest.cc',
        'tools/gn/unique_vector_unittest.cc',
        'tools/gn/value_unittest.cc',
        'tools/gn/visibility_unittest.cc',
        'tools/gn/visual_studio_utils_unittest.cc',
        'tools/gn/visual_studio_writer_unittest.cc',
        'tools/gn/xcode_object_unittest.cc',
        'tools/gn/xml_element_writer_unittest.cc',
        'util/test/gn_test.cc',
      ], 'tool': 'cxx', 'include_dirs': [], 'libs': []},
  }

  if platform.is_posix():
    static_libraries['base']['sources'].extend([
        'base/files/file_enumerator_posix.cc',
        'base/files/file_posix.cc',
        'base/files/file_util_posix.cc',
        'base/posix/file_descriptor_shuffle.cc',
        'base/posix/safe_strerror.cc',
        'base/strings/string16.cc',
    ])

  if platform.is_windows():
    static_libraries['base']['sources'].extend([
        'base/files/file_enumerator_win.cc',
        'base/files/file_util_win.cc',
        'base/files/file_win.cc',
        'base/win/registry.cc',
        'base/win/scoped_handle.cc',
        'base/win/scoped_process_information.cc',
    ])

    libs.extend([
        'advapi32.lib',
        'dbghelp.lib',
        'kernel32.lib',
        'ole32.lib',
        'shell32.lib',
        'user32.lib',
        'userenv.lib',
        'version.lib',
        'winmm.lib',
        'ws2_32.lib',
        'Shlwapi.lib',
    ])

  # we just build static libraries that GN needs
  executables['gn']['libs'].extend(static_libraries.keys())
  executables['gn_unittests']['libs'].extend(static_libraries.keys())

  WriteGenericNinja(path, static_libraries, executables, cc, cxx, ar, ld,
                    platform, host, options, cflags, cflags_cc, ldflags,
                    libflags, include_dirs, libs)


if __name__ == '__main__':
  sys.exit(main(sys.argv[1:]))