[Android] Fix checksum handling when md5sum generates unexpected output.

build/android/pylib/utils/md5sum.py

 # Copyright 2014 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.
 
 import collections
 import logging
 import os
+import re
 import tempfile
 import types
 
 from pylib import cmd_helper
 from pylib import constants
 from pylib.utils import device_temp_file
 
 HashAndPath = collections.namedtuple('HashAndPath', ['hash', 'path'])

[perezju, 2015/04/24 08:06:33]

this is not needed any more

[jbudorick, 2015/04/24 13:56:36]

Removed.

 
 MD5SUM_DEVICE_LIB_PATH = '/data/local/tmp/md5sum/'
 MD5SUM_DEVICE_BIN_PATH = MD5SUM_DEVICE_LIB_PATH + 'md5sum_bin'
 
 MD5SUM_DEVICE_SCRIPT_FORMAT = (
     'test -f {path} -o -d {path} '
     '&& LD_LIBRARY_PATH={md5sum_lib} {device_pie_wrapper} {md5sum_bin} {path}')
 
+_STARTS_WITH_CHECKSUM_RE = re.compile(r'^\s*[0-9a-fA-f]{32}\s+')
+
 
 def CalculateHostMd5Sums(paths):
   """Calculates the MD5 sum value for all items in |paths|.
 
   Args:
     paths: A list of host paths to md5sum.
   Returns:
-    A list of named tuples with 'hash' and 'path' attributes.
+    A dict mapping paths to their respective md5sum checksums.
   """
   if isinstance(paths, basestring):
     paths = [paths]
 
   out = cmd_helper.GetCmdOutput(
       [os.path.join(constants.GetOutDirectory(), 'md5sum_bin_host')] +
           [p for p in paths])
-  return [HashAndPath(*l.split(None, 1)) for l in out.splitlines()]
+
+  return _ParseMd5SumOutput(out.splitlines())
 
 
 def CalculateDeviceMd5Sums(paths, device):
   """Calculates the MD5 sum value for all items in |paths|.
 
   Args:
     paths: A list of device paths to md5sum.
   Returns:
-    A list of named tuples with 'hash' and 'path' attributes.
+    A dict mapping paths to their respective md5sum checksums.
   """
   if isinstance(paths, basestring):
     paths = [paths]
 
   if not device.FileExists(MD5SUM_DEVICE_BIN_PATH):
     device.adb.Push(
         os.path.join(constants.GetOutDirectory(), 'md5sum_dist'),
         MD5SUM_DEVICE_LIB_PATH)
 
   out = []
 
   with tempfile.NamedTemporaryFile() as md5sum_script_file:
     with device_temp_file.DeviceTempFile(
         device.adb) as md5sum_device_script_file:
       device_pie_wrapper = device.GetDevicePieWrapper()
       md5sum_script = (
           MD5SUM_DEVICE_SCRIPT_FORMAT.format(
               path=p, md5sum_lib=MD5SUM_DEVICE_LIB_PATH,
               device_pie_wrapper=device_pie_wrapper,
               md5sum_bin=MD5SUM_DEVICE_BIN_PATH)
           for p in paths)
       md5sum_script_file.write('; '.join(md5sum_script))
       md5sum_script_file.flush()
       device.adb.Push(md5sum_script_file.name, md5sum_device_script_file.name)
       out = device.RunShellCommand(['sh', md5sum_device_script_file.name])
 
-  return [HashAndPath(*l.split(None, 1)) for l in out if l]
+  return _ParseMd5SumOutput(out)
 
+
+def _ParseMd5SumOutput(out):
+  hash_and_path = (l.split(None, 1) for l in out
+                   if l and _STARTS_WITH_CHECKSUM_RE.match(l))
+  return dict((p, h) for h, p in hash_and_path)

[perezju, 2015/04/24 08:06:32]

nit: can be written as:

  return {p: h for h, p in hash_and_path}

[jbudorick, 2015/04/24 13:56:36]

We have generally avoided dictionary comprehensions for reasons I don't
remember.

[perezju, 2015/04/24 14:13:25]

hmmm, strange, but ok.

+