Add RunCommandCaptureOutput as a helper method. It's like RunCommand, but you

lib/cros_build_lib.py

 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Common python commands used by various build scripts."""
 
 import inspect
 import os
 import subprocess
 import sys
@@ skipping 75 matching lines @@
         raise RunCommandException(e)
       else:
         Warning(str(e))
         if print_cmd:
           Info('PROGRAM(%s) -> RunCommand: retrying %r in dir %s' %
                (GetCallerName(), cmd, cwd))
 
   return output
 
 
+def RunCommandCaptureOutput(cmd, print_cmd=True, cwd=None, input=None,
+                            enter_chroot=False,
+                            combine_stdout_stderr=True):
+  """Runs a shell command. Differs from RunCommand, because it allows
+     you to run a command and capture the exit code, output, and stderr
+     all at the same time.
+
+  Arguments:
+    cmd: cmd to run.  Should be input to subprocess.POpen.  If a string,
+      converted to an array using split().
+    print_cmd: prints the command before running it.
+    cwd: the working directory to run this cmd.
+    input: input to pipe into this command through stdin.
+    enter_chroot: this command should be run from within the chroot.  If set,
+      cwd must point to the scripts directory.
+    combine_stdout_stderr -- combine outputs together.
+
+  Returns:
+    Returns a tuple: (exit_code, stdout, stderr) (integer, string, string)
+    stderr is None if combine_stdout_stderr is True
+  """
+  # Set default for variables.
+  stdout = subprocess.PIPE
+  stderr = subprocess.PIPE
+  stdin = None
+
+  # Modify defaults based on parameters.
+  if input:  stdin = subprocess.PIPE
+  if combine_stdout_stderr: stderr = subprocess.STDOUT
+
+  if enter_chroot:  cmd = ['./enter_chroot.sh', '--'] + cmd
+
+  # Print out the command before running.
+  if print_cmd:
+    Info('PROGRAM(%s) -> RunCommand: %r in dir %s' %
+         (GetCallerName(), cmd, cwd))
+
+  proc = subprocess.Popen(cmd, cwd=cwd, stdin=stdin,
+                          stdout=stdout, stderr=stderr)
+  (output, error) = proc.communicate(input)
+
+  # Error is None if stdout, stderr are combined.
+  return proc.returncode, output, error
+
+
 class Color(object):
   """Conditionally wraps text in ANSI color escape sequences."""
   BLACK, RED, GREEN, YELLOW, BLUE, MAGENTA, CYAN, WHITE = range(8)
   BOLD = -1
   COLOR_START = '\033[1;%dm'
   BOLD_START = '\033[1m'
   RESET = '\033[0m'
 
   def __init__(self, enabled=True):
     self._enabled = enabled
@@ skipping 78 matching lines @@
   root_abs_path = os.path.abspath(root_path)
 
   # Strip the repository root from the path and strip first /.
   relative_path = path_abs_path.replace(root_abs_path, '')[1:]
 
   if relative_path == path_abs_path:
     raise Exception('Error: path is outside your src tree, cannot reinterpret.')
 
   new_path = os.path.join('/home', os.getenv('USER'), 'trunk', relative_path)
   return new_path
-