Fix autoupdate to be backwards compatible with previous releases.

src/platform/dev/autoupdate.py

 # Copyright (c) 2009 The Chromium OS 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 buildutil import BuildObject
 from xml.dom import minidom
 
 import os
 import web
 
@@ skipping 40 matching lines @@
     # Removes the portage build prefix.
     latest_version = latest_version.lstrip("g-")
     return latest_version.split('-')[0]
 
   def CanUpdate(self, client_version, latest_version):
     """
       Returns true iff the latest_version is greater than the client_version.
     """
     client_tokens = client_version.split('.')
     latest_tokens = latest_version.split('.')
-    web.debug("client version %s latest version %s" % (client_version, latest_version))
+    web.debug("client version %s latest version %s" \
+        % (client_version, latest_version))
     for i in range(0,4):
       if int(latest_tokens[i]) == int(client_tokens[i]):
         continue
       return int(latest_tokens[i]) > int(client_tokens[i])
     return False
 
   def BuildUpdateImage(self, image_path):
     image_file = "%s/rootfs.image" % image_path
     web.debug("checking image file %s/update.gz" % image_path)
     if not os.path.exists("%s/update.gz" % image_path):
       mkupdate = "%s/mk_memento_images.sh %s" % (self.scripts_dir, image_file)
       web.debug(mkupdate)
       err = os.system(mkupdate)
       if err != 0:
         web.debug("failed to create update image")
         return False
 
     web.debug("Found an image, copying it to static")
     err = os.system("cp %s/update.gz %s" % (image_path, self.static_dir))
     if err != 0:
-      web.debug("Unable to move update.gz from %s to %s" % (image_path, self.static_dir))
+      web.debug("Unable to move update.gz from %s to %s" \
+          % (image_path, self.static_dir))
       return False
     return True
 
   def GetSize(self, update_path):
     return os.path.getsize(update_path)
 
   def GetHash(self, update_path):
-    cmd = "cat %s | openssl sha1 -binary | openssl base64 | tr \'\\n\' \' \';" % update_path
+    cmd = "cat %s | openssl sha1 -binary | openssl base64 | tr \'\\n\' \' \';" \
+        % update_path
     web.debug(cmd)
     return os.popen(cmd).read()
 
   def HandleUpdatePing(self, data):
     update_dom = minidom.parseString(data)
     root = update_dom.firstChild
     query = root.getElementsByTagName("o:app")[0]
-    client_version = query.attributes['version'].value
-    board_id = query.attributes['board'].value
-    latest_image_path = self.GetLatestImagePath(board_id);
-    latest_version = self.GetLatestVersion(latest_image_path);
-    if client_version != "ForcedUpdate" and not self.CanUpdate(client_version, latest_version):
+    client_version = query.getAttribute('version')
+    board_id = query.hasAttribute('board') and query.getAttribute('board') \
+        or "x86-generic"
+    latest_image_path = self.GetLatestImagePath(board_id)
+    latest_version = self.GetLatestVersion(latest_image_path)
+    if client_version != "ForcedUpdate" \
+        and not self.CanUpdate(client_version, latest_version):
       web.debug("no update")
       return self.GetNoUpdatePayload()
 
     web.debug("update found %s " % latest_version)
     ok = self.BuildUpdateImage(latest_image_path)
     if ok != True:
       web.debug("Failed to build an update image")
       return self.GetNoUpdatePayload()
 
     hash = self.GetHash("%s/update.gz" % self.static_dir)
     size = self.GetSize("%s/update.gz" % self.static_dir)
     hostname = web.ctx.host
     url = "http://%s/static/update.gz" % hostname
     return self.GetUpdatePayload(hash, size, url)