DeviceUtils.StartInstrumentation: Shrink command-line

build/android/devil/utils/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
@@ skipping 49 matching lines @@
     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 ShrinkToSnippet(cmd_parts, var_name, var_value):
+  """Constructs a shell snippet for a command using a variable to shrink it.
+
+  Takes into account all quoting that needs to happen.
+
+  Args:
+    cmd_parts: A list of command arguments.
+    var_name: The variable that holds var_value.
+    var_value: The string to replace in cmd_parts with $var_name
+
+  Returns:
+    A shell snippet that does not include setting the variable.
+  """
+  def shrink(value):
+    parts = (x and SingleQuote(x) for x in value.split(var_value))
+    with_substitutions = ('"$%s"' % var_name).join(parts)
+    return with_substitutions or "''"
+
+  return ' '.join(shrink(part) for part in cmd_parts)
+
+
 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,
                env=env)
@@ skipping 201 matching lines @@
     buffer_output += data
     has_incomplete_line = buffer_output[-1] not in '\r\n'
     lines = buffer_output.splitlines()
     buffer_output = lines.pop() if has_incomplete_line else ''
     for line in lines:
       yield line
   if buffer_output:
     yield buffer_output
   if check_status and process.returncode:
     raise subprocess.CalledProcessError(process.returncode, cmd)