Add input md5 check to create_device_library_links.py

build/android/gyp/create_device_library_links.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.
 
 """Creates symlinks to native libraries for an APK.
 
 The native libraries should have previously been pushed to the device (in
 options.target_dir). This script then creates links in an apk's lib/ folder to
 those native libraries.
 """
 
 import json
 import optparse
 import os
 import sys
 
 from util import build_utils
+from util import md5_check
 
 BUILD_ANDROID_DIR = os.path.join(os.path.dirname(__file__), '..')
 sys.path.append(BUILD_ANDROID_DIR)
 
 from pylib import android_commands
 from pylib.utils import apk_helper
 
 
-def CreateLinks(options):
-  libraries = build_utils.ReadJson(options.libraries_json)
-  apk_package = apk_helper.GetPackageName(options.apk)
-
-  # There is a large (~100ms) overhead for each call to adb.RunShellCommand. To
-  # avoid this overhead, craft a single command that creates all the links.
-  link = '/data/data/' + apk_package + '/lib/$f'
-  target = options.target_dir + '/$f'
-  names = ' '.join(libraries)
+def RunLinkCommand(adb, target, link):
   cmd = (
-      'for f in ' + names + '; do \n' +
-        'rm ' + link + ' > /dev/null 2>&1 \n' +
-        'ln -s ' + target + ' ' + link + '\n' +
-      'done'
+      'rm ' + link + ' > /dev/null 2>&1 \n'
+      'ln -s ' + target + ' ' + link + '\n'
       )
-
-  adb = android_commands.AndroidCommands()
   result = adb.RunShellCommand(cmd)
 
   if result:
     raise Exception(
         'Unexpected output creating links on device.\n' +
         '\n'.join(result))
 
 
+def CreateLinks(options):
+  libraries = build_utils.ReadJson(options.libraries_json)
+  apk_package = apk_helper.GetPackageName(options.apk)
+
+  adb = android_commands.AndroidCommands()
+  serial_number = adb.Adb().GetSerialNumber()
+  for lib in libraries:
+    host_path = os.path.join(options.libraries_dir, lib)
+
+    md5_stamp = '%s.%s.link.md5' % (host_path, serial_number)
+    md5_checker = md5_check.Md5Checker(stamp=md5_stamp, inputs=[host_path])
+    if md5_checker.IsStale():
+      link = '/data/data/' + apk_package + '/lib/' + lib
+      target = options.target_dir + '/' + lib
+      RunLinkCommand(adb, target, link)
+      md5_checker.Write()
+
+
 def main(argv):
   parser = optparse.OptionParser()
   parser.add_option('--apk', help='Path to the apk.')
   parser.add_option('--libraries-json',
       help='Path to the json list of native libraries.')
   parser.add_option('--target-dir',
       help='Device directory that contains the target libraries for symlinks.')
+  parser.add_option('--libraries-dir',
+      help='Directory that contains stripped libraries '
+      '(used to determine if a library has changed since last push).')
   parser.add_option('--stamp', help='Path to touch on success.')
   options, _ = parser.parse_args()
 
-  required_options = ['apk', 'libraries_json', 'target_dir']
+  required_options = ['apk', 'libraries_json', 'target_dir', 'libraries_dir']
   build_utils.CheckOptions(options, parser, required=required_options)
 
   CreateLinks(options)
 
   if options.stamp:
     build_utils.Touch(options.stamp)
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv))