New run shell implementation for DeviceUtils

build/android/pylib/cmd_helper.py

Index: build/android/pylib/cmd_helper.py
diff --git a/build/android/pylib/cmd_helper.py b/build/android/pylib/cmd_helper.py
index aba00be735368e9e931e321b14bef1d46ad1fbf3..b99db589d516b1baf1f980eb7a6f0798631c5d82 100644
--- a/build/android/pylib/cmd_helper.py
+++ b/build/android/pylib/cmd_helper.py
@@ -9,6 +9,7 @@ import os
 import pipes
 import select
 import signal
+import string
 import StringIO
 import subprocess
 import time
@@ -19,6 +20,27 @@ try:
 except ImportError:
   fcntl = None
 
+_SafeShellChars = frozenset(string.ascii_letters + string.digits + '@%_-+=:,./')
+
+quote = pipes.quote

[jbudorick, 2014/10/17 09:04:52]

I don't think I like this. Let callers use pipes.quote.

+
+def dquote(s):

[jbudorick, 2014/10/17 09:04:53]

While I understand that you're mimicking pipes.quote, I don't think I like
breaking our style guide here by starting with a lower-case letter.

[perezju, 2014/10/17 11:17:09]

Done.

+  """Return an escaped version of the string using double quotes.
+
+  A sibling to pipes.quote that uses double rather than single quotes.
+  Meant to be used to quote strings which may contain unsafe characters (e.g.
+  spaces), while retaining some shell features such as variable interpolation.
+
+  The set of characters that retain their special meaning may depend on the
+  shell implementation. It usually includes: '$', '`', '\', '!', '*', and '@'.
+  """
+  if not s:

[jbudorick, 2014/10/17 09:04:52]

Also, this function should have some unit tests.

[perezju, 2014/10/17 11:17:09]

Done.

+    return '""'
+  if all(c in _SafeShellChars for c in s):
+    return s
+  else:
+    return '"' + s.replace('"', '\\"') + '"'
+
 
 def Popen(args, stdout=None, stderr=None, shell=None, cwd=None, env=None):
   return subprocess.Popen(
@@ -88,7 +110,7 @@ def GetCmdStatusAndOutput(args, cwd=None, shell=False):
   elif shell:
     raise Exception('array args must be run with shell=False')
   else:
-    args_repr = ' '.join(map(pipes.quote, args))
+    args_repr = ' '.join(map(quote, args))
 
   s = '[host]'
   if cwd: