device_utils.Install: Calculate host md5s at the same time as device md5s

build/android/pylib/device/device_utils.py

Index: build/android/pylib/device/device_utils.py
diff --git a/build/android/pylib/device/device_utils.py b/build/android/pylib/device/device_utils.py
index 8064ce88cb28eccde7773258d5f56f29e21fc78f..f7a71c1ee96ba8e9c39760f8ac3c31421f347ac4 100644
--- a/build/android/pylib/device/device_utils.py
+++ b/build/android/pylib/device/device_utils.py
@@ -19,6 +19,7 @@ import re
 import shutil
 import sys
 import tempfile
+import threading
 import time
 import zipfile
 
@@ -1092,11 +1093,16 @@ class DeviceUtils(object):
     return ret
 
   def _ComputeStaleApks(self, package_name, host_apk_paths):
-    host_checksums = md5sum.CalculateHostMd5Sums(host_apk_paths)
+    host_checksums_holder = [None]
+    def DoComputeHostChecksums():

[jbudorick, 2015/08/11 18:06:40]

nit: I've generally been trying to keep local functions within pylib as
lower_case_with_underscores to distinguish them.

[agrieve, 2015/08/11 18:15:00]

Done.

+      host_checksums_holder[0] = md5sum.CalculateHostMd5Sums(host_apk_paths)

[jbudorick, 2015/08/11 18:06:40]

nit: line break after function definition

[agrieve, 2015/08/11 18:15:00]

Done.

+    host_thread = threading.Thread(target=DoComputeHostChecksums)

[jbudorick, 2015/08/11 18:06:40]

I'd prefer it if you used a timeout_retry thread:
https://code.google.com/p/chromium/codesearch#chromium/src/build/android/pyli...

(this doesn't need retries, but a timeout would be nice in case something
strange happens)

[agrieve, 2015/08/11 18:15:00]

Since this is a private helper, and all public methods use their own timeout
logic, having a timeout within a timeout seems like overkill.

[jbudorick, 2015/08/11 18:16:54]

ah, right.

+    host_thread.start()
     device_checksums = self._ComputeDeviceChecksumsForApks(package_name)
-    stale_apks = [k for (k, v) in host_checksums.iteritems()
+    host_thread.join()
+    stale_apks = [k for (k, v) in host_checksums_holder[0].iteritems()
                   if v not in device_checksums]
-    return stale_apks, set(host_checksums.values())
+    return stale_apks, set(host_checksums_holder[0].values())
 
   def _PushFilesImpl(self, host_device_tuples, files):
     size = sum(host_utils.GetRecursiveDiskUsage(h) for h, _ in files)