#!/usr/bin/python2.4
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"""Code signing build tool.

This module sets up code signing.
It is used as follows:
  env = Environment(tools = ["code_signing"])
To sign an EXE/DLL do:
  env.SignedBinary('hello_signed.exe', 'hello.exe',
                   CERTIFICATE_FILE='bob.pfx',
                   CERTIFICATE_PASSWORD='123',
                   TIMESTAMP_SERVER='')
If no certificate file is specified, copying instead of signing will occur.
If an empty timestamp server string is specified, there will be no timestamp.
"""

import SCons.Script


def generate(env):
  # NOTE: SCons requires the use of this name, which fails gpylint.
  """SCons entry point for this tool."""

  env.Replace(
      # Path to Microsoft signtool.exe
      SIGNTOOL='$VC80_DIR/common7/tools/bin/signtool.exe',
      # No certificate by default.
      CERTIFICATE_PATH='',
      # No certificate password by default.
      CERTIFICATE_PASSWORD='',
      # The default timestamp server.
      TIMESTAMP_SERVER='http://timestamp.verisign.com/scripts/timestamp.dll',
  )

  # Setup Builder for Signing
  env['BUILDERS']['SignedBinary'] = SCons.Script.Builder(
      generator=SignedBinaryGenerator,
      emitter=SignedBinaryEmitter)


def SignedBinaryEmitter(target, source, env):
  """Add the signing certificate (if any) to the source dependencies."""
  if env['CERTIFICATE_PATH']:
    source.append(env['CERTIFICATE_PATH'])
  return target, source


def SignedBinaryGenerator(source, target, env, for_signature):
  """A builder generator for code signing."""
  source = source                # Silence gpylint.
  target = target                # Silence gpylint.
  for_signature = for_signature  # Silence gpylint.

  # Alway copy and make writable.
  commands = [
      SCons.Script.Copy('$TARGET', '$SOURCE'),
      SCons.Script.Chmod('$TARGET', 0755),
  ]

  # Only do signing if there is a certificate path.
  if env['CERTIFICATE_PATH']:
    # The command used to do signing (target added on below).
    signing_cmd = '$SIGNTOOL sign /f "$CERTIFICATE_PATH"'
    # Add certificate password if any.
    if env['CERTIFICATE_PASSWORD']:
      signing_cmd += ' /p "$CERTIFICATE_PASSWORD"'
    # Add timestamp server if any.
    if env['TIMESTAMP_SERVER']:
      signing_cmd += ' /t "$TIMESTAMP_SERVER"'
    # Add in target name
    signing_cmd += ' $TARGET'
    # Add the signing to the list of commands to perform.
    commands.append(signing_cmd)

  return commands