Add more error checking to preflight queue.

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 120 matching lines @@
 def Info(message):
   """Emits a blue informational message and continues execution.
 
   Keyword arguments:
     message: The message to be emitted.
   """
   print >> sys.stderr, (
       Color(_STDOUT_IS_TTY).Color(Color.BLUE, '\nINFO: ' + message))
 
 
-def FindRepoDir():
-  """Returns the nearest higher-level repo dir from the cwd."""
-  cwd = os.getcwd()
-  while cwd != '/':
-    repo_dir = os.path.join(cwd, '.repo')
+def FindRepoDir(path=None):
+  """Returns the nearest higher-level repo dir from the specified path.
+
+  Args:
+    path: The path to use. Defaults to cwd.
+  """
+  if path is None:
+    path = os.getcwd()
+  while path != '/':
+    repo_dir = os.path.join(path, '.repo')
     if os.path.isdir(repo_dir):
       return repo_dir
-    cwd = os.path.dirname(cwd)
+    path = os.path.dirname(path)
   return None
 
 
 def ReinterpretPathForChroot(path):
   """Returns reinterpreted path from outside the chroot for use inside.
 
   Keyword arguments:
     path: The path to reinterpret.  Must be in src tree.
   """
-  root_path = os.path.join(FindRepoDir(), '..')
+  root_path = os.path.join(FindRepoDir(path), '..')
 
   path_abs_path = os.path.abspath(path)
   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