Re-invent page aligning libraries in APK file.

build/android/gyp/finalize_apk.py

 #!/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 shutil
 import sys
 import tempfile
 
 from util import build_utils
 
-def RenameLibInApk(rezip_path, in_zip_file, out_zip_file):
-  rename_cmd = [
-      rezip_path,
-      'rename',
+def AddPageAlignment(prealign_path, in_zip_file, out_zip_file):
+  prealign_cmd = [
+      'java',
+      '-classpath',
+      prealign_path,
+      'PrealignApk',
+      'addalignment',
       in_zip_file,
       out_zip_file,
     ]
-  build_utils.CheckOutput(rename_cmd)
+  build_utils.CheckOutput(prealign_cmd)
 
 
-def SignApk(key_path, key_name, key_passwd, unsigned_path, signed_path):
+def ReorderApk(prealign_path, in_zip_file, out_zip_file):
+  prealign_cmd = [
+      'java',
+      '-classpath',
+      prealign_path,
+      'PrealignApk',
+      'reorder',
+      in_zip_file,
+      out_zip_file,
+    ]
+  build_utils.CheckOutput(prealign_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, unaligned_path, final_path):
   align_cmd = [
       zipalign_path,
       '-f', '4',  # 4 bytes
       unaligned_path,
       final_path,
       ]
   build_utils.CheckOutput(align_cmd)
 
 
-def UncompressLibAndPageAlignInApk(rezip_path, in_zip_file, out_zip_file):
+def RenameAndUncompressLibInApk(rezip_path, in_zip_file, out_zip_file):
   rename_cmd = [
       rezip_path,
-      'inflatealign',
+      'renameinflate',
       in_zip_file,
       out_zip_file,
     ]
-  build_utils.CheckOutput(rename_cmd)
-
-
-def DropDataDescriptorsInApk(rezip_path, in_zip_file, out_zip_file):
-  rename_cmd = [
-      rezip_path,
-      'dropdescriptors',
-      in_zip_file,
-      out_zip_file,
-    ]
   build_utils.CheckOutput(rename_cmd)
 
 
 def main():
   parser = optparse.OptionParser()
   build_utils.AddDepfileOption(parser)
 
+  parser.add_option('--prealign-path', help='Path to the prealign tool.')
   parser.add_option('--zipalign-path', help='Path to the zipalign tool.')
   parser.add_option('--rezip-path', help='Path to the rezip executable.')
   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-file', 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()
 
   with tempfile.NamedTemporaryFile() as signed_apk_path_tmp, \
       tempfile.NamedTemporaryFile() as apk_to_sign_tmp, \
-      tempfile.NamedTemporaryFile() as apk_without_descriptors_tmp, \
-      tempfile.NamedTemporaryFile() as aligned_apk_tmp:
+      tempfile.NamedTemporaryFile() as uncompress_lib_apk_tmp:
 
     if options.load_library_from_zip_file:
       # 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.
+      # 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.
+      uncompress_lib_apk_path = uncompress_lib_apk_tmp.name
+      RenameAndUncompressLibInApk(
+          options.rezip_path, options.unsigned_apk_path,
+          uncompress_lib_apk_path)
       apk_to_sign = apk_to_sign_tmp.name
-      RenameLibInApk(options.rezip_path, options.unsigned_apk_path, apk_to_sign)
+      # Move the library to a page boundary by adding a page alignment file.
+      AddPageAlignment(
+          options.prealign_path, uncompress_lib_apk_path, apk_to_sign)
     else:
       apk_to_sign = options.unsigned_apk_path
 
     signed_apk_path = signed_apk_path_tmp.name
-    SignApk(options.key_path, options.key_name, options.key_passwd,
-            apk_to_sign, signed_apk_path)
+    JarSigner(options.key_path, options.key_name, options.key_passwd,
+              apk_to_sign, signed_apk_path)
 
     if options.load_library_from_zip_file:
-      # Signing adds data descriptors to the APK. These are redundant
-      # information. We remove them as otherwise they can cause a
-      # miscalculation in the page alignment.
-      apk_to_align = apk_without_descriptors_tmp.name
-      DropDataDescriptorsInApk(
-          options.rezip_path, signed_apk_path, apk_to_align)
-      aligned_apk = aligned_apk_tmp.name
+      # Reorder the contents of the APK. This re-establishes the canonical
+      # order which means the library will be back at its page aligned location.
+      ReorderApk(options.prealign_path, signed_apk_path, options.final_apk_path)

[rmcilroy, 2014/09/29 11:38:32]

Given that ReorderApk also aligns the APK, could you mention that in the comment
above and name this function ReorderAndAlignApk, just so nobody is tempted to do
the AlignApk step on the output of this step.

[Anton, 2014/09/29 16:30:17]

Done.

     else:
-      apk_to_align = signed_apk_path
-      aligned_apk = options.final_apk_path
-
-    # Align uncompress items to 4 bytes
-    AlignApk(options.zipalign_path, apk_to_align, aligned_apk)
-
-    if options.load_library_from_zip_file:
-      # Uncompress the library and make sure that it is page aligned.
-      UncompressLibAndPageAlignInApk(
-          options.rezip_path, aligned_apk, options.final_apk_path)
+      # Align uncompress items to 4 bytes
+      AlignApk(options.zipalign_path, signed_apk_path, options.final_apk_path)
 
   if options.depfile:
     build_utils.WriteDepfile(
         options.depfile, build_utils.GetPythonDependencies())
 
   if options.stamp:
     build_utils.Touch(options.stamp)
 
 
 if __name__ == '__main__':
   sys.exit(main())