New run shell implementation for DeviceUtils

build/android/pylib/cmd_helper.py

 # Copyright (c) 2012 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.
 
 """A wrapper for subprocess to make calling shell commands easier."""
 
 import logging
 import os
 import pipes
 import select
 import signal
+import string
 import StringIO
 import subprocess
 import time
 
 # fcntl is not available on Windows.
 try:
   import fcntl
 except ImportError:
   fcntl = None
 
+_SafeShellChars = frozenset(string.ascii_letters + string.digits + '@%_-+=:,./')
+
+def SingleQuote(s):
+  """Return an shell-escaped version of the string using single quotes.
+
+  Reliably quote a string which may contain unsafe characters (e.g. space,
+  quote, or other special characters such as '$').
+
+  The returned value can be used in a shell command line as one token that gets
+  to be interpreted literally.
+
+  Args:
+    s: The string to quote.
+
+  Return:
+    The string quoted using single quotes.
+  """
+  return pipes.quote(s)
+
+def DoubleQuote(s):
+  """Return an shell-escaped version of the string using double quotes.
+
+  Reliably quote a string which may contain unsafe characters (e.g. space
+  or quote characters), while retaining some shell features such as variable
+  interpolation.
+
+  The returned value can be used in a shell command line as one token that gets
+  to be further interpreted by the shell.
+
+  The set of characters that retain their special meaning may depend on the
+  shell implementation. This set usually includes: '$', '`', '\', '!', '*',
+  and '@'.
+
+  Args:
+    s: The string to quote.
+
+  Return:
+    The string quoted using double quotes.
+  """
+  if not s:
+    return '""'
+  elif 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(
       args=args, cwd=cwd, stdout=stdout, stderr=stderr,
       shell=shell, close_fds=True, env=env,
       preexec_fn=lambda: signal.signal(signal.SIGPIPE, signal.SIG_DFL))
 
 
 def Call(args, stdout=None, stderr=None, shell=None, cwd=None, env=None):
   pipe = Popen(args, stdout=stdout, stderr=stderr, shell=shell, cwd=cwd,
@@ skipping 49 matching lines @@
   Returns:
     The 2-tuple (exit code, output).
   """
   if isinstance(args, basestring):
     args_repr = args
     if not shell:
       raise Exception('string args must be run with shell=True')
   elif shell:
     raise Exception('array args must be run with shell=False')
   else:
-    args_repr = ' '.join(map(pipes.quote, args))
+    args_repr = ' '.join(map(SingleQuote, args))
 
   s = '[host]'
   if cwd:
     s += ':' + cwd
   s += '> ' + args_repr
   logging.info(s)
   pipe = Popen(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                shell=shell, cwd=cwd)
   stdout, stderr = pipe.communicate()
 
@@ skipping 56 matching lines @@
         break
   finally:
     try:
       # Make sure the process doesn't stick around if we fail with an
       # exception.
       process.kill()
     except OSError:
       pass
     process.wait()
   return process.returncode, output.getvalue()