#!/usr/bin/env python
#
# Copyright 2013 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.
"""Signs and zipaligns APK.

"""

import optparse
import os
import shutil
import sys
import tempfile
import zipfile

# resource_sizes modifies zipfile for zip64 compatibility. See
# https://bugs.python.org/issue14315.
sys.path.append(os.path.join(os.path.dirname(__file__), os.pardir))
import resource_sizes  # pylint: disable=unused-import

from util import build_utils

def RenameInflateAndAddPageAlignment(
    rezip_apk_jar_path, in_zip_file, out_zip_file):
  rezip_apk_cmd = [
      'java',
      '-classpath',
      rezip_apk_jar_path,
      'RezipApk',
      'renamealign',
      in_zip_file,
      out_zip_file,
    ]
  build_utils.CheckOutput(rezip_apk_cmd)


def ReorderAndAlignApk(rezip_apk_jar_path, in_zip_file, out_zip_file):
  rezip_apk_cmd = [
      'java',
      '-classpath',
      rezip_apk_jar_path,
      'RezipApk',
      'reorder',
      in_zip_file,
      out_zip_file,
    ]
  build_utils.CheckOutput(rezip_apk_cmd)


def JarSigner(key_path, key_name, key_passwd, unsigned_path, signed_path):
  shutil.copy(unsigned_path, signed_path)
  sign_cmd = [
      'jarsigner',
      '-sigalg', 'MD5withRSA',
      '-digestalg', 'SHA1',
      '-keystore', key_path,
      '-storepass', key_passwd,
      signed_path,
      key_name,
    ]
  build_utils.CheckOutput(sign_cmd)


def AlignApk(zipalign_path, package_align, unaligned_path, final_path):
  align_cmd = [
      zipalign_path,
      '-f'
      ]

  if package_align:
    align_cmd += ['-p']

  align_cmd += [
      '4',  # 4 bytes
      unaligned_path,
      final_path,
      ]
  build_utils.CheckOutput(align_cmd)


def main(args):
  args = build_utils.ExpandFileArgs(args)

  parser = optparse.OptionParser()
  build_utils.AddDepfileOption(parser)

  parser.add_option('--rezip-apk-jar-path',
                    help='Path to the RezipApk jar file.')
  parser.add_option('--zipalign-path', help='Path to the zipalign tool.')
  parser.add_option('--page-align-shared-libraries',
                    action='store_true',
                    help='Page align shared libraries.')
  parser.add_option('--unsigned-apk-path', help='Path to input unsigned APK.')
  parser.add_option('--final-apk-path',
      help='Path to output signed and aligned APK.')
  parser.add_option('--key-path', help='Path to keystore for signing.')
  parser.add_option('--key-passwd', help='Keystore password')
  parser.add_option('--key-name', help='Keystore name')
  parser.add_option('--stamp', help='Path to touch on success.')
  parser.add_option('--load-library-from-zip', type='int',
      help='If non-zero, build the APK such that the library can be loaded ' +
           'directly from the zip file using the crazy linker. The library ' +
           'will be renamed, uncompressed and page aligned.')

  options, _ = parser.parse_args()

  input_paths = [
    options.unsigned_apk_path,
    options.key_path,
  ]

  if options.load_library_from_zip:
    input_paths.append(options.rezip_apk_jar_path)

  input_strings = [
    options.load_library_from_zip,
    options.key_name,
    options.key_passwd,
    options.page_align_shared_libraries,
  ]

  build_utils.CallAndWriteDepfileIfStale(
      lambda: FinalizeApk(options),
      options,
      record_path=options.unsigned_apk_path + '.finalize.md5.stamp',
      input_paths=input_paths,
      input_strings=input_strings,
      output_paths=[options.final_apk_path])


def FinalizeApk(options):
  with tempfile.NamedTemporaryFile() as signed_apk_path_tmp, \
      tempfile.NamedTemporaryFile() as apk_to_sign_tmp:

    if options.load_library_from_zip:
      # We alter the name of the library so that the Android Package Manager
      # does not extract it into a separate file. This must be done before
      # signing, as the filename is part of the signed manifest. At the same
      # time we uncompress the library, which is necessary so that it can be
      # loaded directly from the APK.
      # Move the library to a page boundary by adding a page alignment file.
      apk_to_sign = apk_to_sign_tmp.name
      RenameInflateAndAddPageAlignment(
          options.rezip_apk_jar_path, options.unsigned_apk_path, apk_to_sign)
    else:
      apk_to_sign = options.unsigned_apk_path

    signed_apk_path = signed_apk_path_tmp.name
    JarSigner(options.key_path, options.key_name, options.key_passwd,
              apk_to_sign, signed_apk_path)

    # Make the signing files hermetic.
    with tempfile.NamedTemporaryFile(suffix='.zip') as hermetic_signed_apk:
      with zipfile.ZipFile(signed_apk_path, 'r') as zi:
        with zipfile.ZipFile(hermetic_signed_apk, 'w') as zo:
          for info in zi.infolist():
            # Ignore 'extended local file headers'. Python doesn't write them
            # properly (see https://bugs.python.org/issue1742205) which causes
            # zipalign to miscalculate alignment. Since we don't use them except
            # for alignment anyway, we write a stripped file here and let
            # zipalign add them properly later. eLFHs are controlled by 'general
            # purpose bit flag 03' (0x08) so we mask that out.
            info.flag_bits = info.flag_bits & 0xF7

            info.date_time = build_utils.HERMETIC_TIMESTAMP
            zo.writestr(info, zi.read(info.filename))

      shutil.copy(hermetic_signed_apk.name, signed_apk_path)

    if options.load_library_from_zip:
      # Reorder the contents of the APK. This re-establishes the canonical
      # order which means the library will be back at its page aligned location.
      # This step also aligns uncompressed items to 4 bytes.
      ReorderAndAlignApk(
          options.rezip_apk_jar_path, signed_apk_path, options.final_apk_path)
    else:
      # Align uncompressed items to 4 bytes
      AlignApk(options.zipalign_path,
               options.page_align_shared_libraries,
               signed_apk_path,
               options.final_apk_path)


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