text: # 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.
  
  from __future__ import print_function
  
  import json
  import os
  import os.path
  import subprocess
  import sys
  
  
  script_dir = os.path.dirname(os.path.realpath(__file__))
  json_data_file = os.path.join(script_dir, 'win_toolchain.json')
  
  
  def SetEnvironmentForCPU(cpu):
    """Sets the environment to build with the selected toolchain for |cpu|."""
    with open(json_data_file, 'r') as tempf:
      toolchain_data = json.load(tempf)
    sdk_dir = toolchain_data['win_sdk']
    os.environ['WINDOWSSDKDIR'] = sdk_dir
    os.environ['WDK_DIR'] = toolchain_data['wdk']
    # Include the VS runtime in the PATH in case it's not machine-installed.
    vs_runtime_dll_dirs = toolchain_data['runtime_dirs']
    runtime_path = os.pathsep.join(vs_runtime_dll_dirs)
    os.environ['PATH'] = runtime_path + os.pathsep + os.environ['PATH']
  
    # Set up the architecture-specific environment from the SetEnv files. See
    # _LoadToolchainEnv() from setup_toolchain.py in Chromium.
    assert cpu in ('x86', 'x64', 'arm', 'arm64')
    with open(os.path.join(sdk_dir, 'bin', 'SetEnv.%s.json' % cpu)) as f:
      env = json.load(f)['env']
    if env['VSINSTALLDIR'] == [["..", "..\\"]]:
      # Old-style paths were relative to the win_sdk\bin directory.
      json_relative_dir = os.path.join(sdk_dir, 'bin')
    else:
      # New-style paths are relative to the toolchain directory.
      json_relative_dir = toolchain_data['path']
    for k in env:
      entries = [os.path.join(*([json_relative_dir] + e)) for e in env[k]]
      # clang-cl wants INCLUDE to be ;-separated even on non-Windows,
      # lld-link wants LIB to be ;-separated even on non-Windows.  Path gets :.
      sep = os.pathsep if k == 'PATH' else ';'
      env[k] = sep.join(entries)
    # PATH is a bit of a special case, it's in addition to the current PATH.
    env['PATH'] = env['PATH'] + os.pathsep + os.environ['PATH']
  
    for k, v in env.items():
      os.environ[k] = v
  
  
  def FindDepotTools():
    """Returns the path to depot_tools in $PATH."""
    for path in os.environ['PATH'].split(os.pathsep):
      if os.path.isfile(os.path.join(path, 'gclient.py')):
        return path
    raise Exception("depot_tools not found!")
  
  
  def _GetDesiredVsToolchainHashes(version):
    """Load a list of SHA1s corresponding to the toolchains that we want installed
    to build with."""
    if version == '2015':
      # Update 3 final with 10.0.15063.468 SDK and no vctip.exe.
      return ['f53e4598951162bad6330f7a167486c7ae5db1e5']
    if version == '2017':
      # VS 2017 Update 9 (15.9.12) with 10.0.18362 SDK, 10.0.17763 version of
      # Debuggers, and 10.0.17134 version of d3dcompiler_47.dll, with ARM64
      # libraries.
      return ['418b3076791776573a815eb298c8aa590307af63']
    if version == '2019':
      # VS 2019 16.61 with 10.0.19041 SDK, and 10.0.20348 version of
      # d3dcompiler_47.dll, with ARM64 libraries and UWP support.
      return ['3bda71a11e']
    raise Exception('Unsupported VS version %s' % version)
  
  
  def Update(version):
    """Requests an update of the toolchain to the specific hashes we have at
    this revision. The update outputs a .json of the various configuration
    information required to pass to vs_env.py which we use in
    |SetEnvironmentForCPU()|.
    """
    depot_tools_path = FindDepotTools()
    get_toolchain_args = [
        sys.executable,
        os.path.join(depot_tools_path,
                    'win_toolchain',
                    'get_toolchain_if_necessary.py'),
        '--output-json', json_data_file,
      ] + _GetDesiredVsToolchainHashes(version)
    subprocess.check_call(get_toolchain_args)
    return 0
  
  
  def main():
    if not sys.platform.startswith(('win32', 'cygwin')):
      return 0
    commands = {
        'update': Update,
    }
    if len(sys.argv) < 2 or sys.argv[1] not in commands:
      print('Expected one of: %s' % ', '.join(commands), file=sys.stderr)
      return 1
    return commands[sys.argv[1]](*sys.argv[2:])
  
  
  if __name__ == '__main__':
    sys.exit(main())
  