Check the existence and executability of scm commands

gclient_utils.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.
 
 """Generic utils."""
 
 import errno
 import logging
 import os
 import Queue
@@ skipping 175 matching lines @@
       os.makedirs(tree)
     except OSError, e:
       # 17 POSIX, 183 Windows
       if e.errno not in (17, 183):
         raise
       if count > 40:
         # Give up.
         raise
 
 
+def FindCommandExecutable(cmd):
+  """Finds the specified |cmd| in $PATH and returns its path.  Returns None
+  if it's not found."""
+  for path in os.environ['PATH'].split(os.pathsep):
+    full_path = os.path.join(path, cmd)
+    if os.path.isfile(full_path) and os.access(full_path, os.X_OK):
+      return full_path
+  return None
+
+
 def CheckCallAndFilterAndHeader(args, always=False, **kwargs):
   """Adds 'header' support to CheckCallAndFilter.
 
   If |always| is True, a message indicating what is being done
   is printed to stdout all the time even if not output is generated. Otherwise
   the message header is printed only if the call generated any ouput.
   """
   stdout = kwargs.get('stdout', None) or sys.stdout
   if always:
     stdout.write('\n________ running \'%s\' in \'%s\'\n'
@@ skipping 560 matching lines @@
     keyvals = dict([x.strip() for x in l.split(':', 1)] for l in lines if l)
   except ValueError:
     raise Error(
         'Failed to process settings, please fix. Content:\n\n%s' % content)
   def fix_url(key):
     if keyvals.get(key):
       keyvals[key] = UpgradeToHttps(keyvals[key])
   fix_url('CODE_REVIEW_SERVER')
   fix_url('VIEW_VC')
   return keyvals