Adding debug information to multiemitter.py

tools/dom/scripts/multiemitter.py

 #!/usr/bin/python
 # Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 """Templating to help generate structured text."""
 
 import os
 import re
+import sys
+import subprocess
 import emitter
 import logging
 
 _logger = logging.getLogger('multiemitter')
 
 class MultiEmitter(object):
   """A set of Emitters that write to different files.
 
   Each entry has a key.
 
@@ skipping 45 matching lines @@
       emitter = self._filename_to_emitter[file]
       writer(file, emitter.Fragments())
 
 
 def _WriteFile(path, lines):
   (dir, file) = os.path.split(path)
 
   # Ensure dir exists.
   if dir:
     if not os.path.isdir(dir):
+      _logger.info('Mkdir - %s' % dir)
       os.makedirs(dir)
 
   # Remove file if pre-existing.
   if os.path.exists(path):
+    _logger.info('Removing - %s' % path)
     os.remove(path)
 
   # Write the file.
-  # _logger.info('Flushing - %s' % path)
-  f = open(path, 'w')
-  f.writelines(lines)
-  f.close()
+  try:
+    _logger.info('Writing - %s' % path)
+    f = open(path, 'w')
+    f.writelines(lines)
+    f.close()
+  except OSError as error:
+    # FIXME(kustermann): Remove this later on.
+    # We try to get more debugging information to figure out why we sometimes
+    # get a "Permission denied" error when opening the file for writing.
+    # (hypothesis: Another process has already opened the file.)
+    _logger.info('Got exception (%s) ' % error)
+
+    if sys.platform  == 'win32':
+      handle_file = r'E:\handle.exe'
+      if os.path.exists(handle_file):
+        _logger.info('Running handle.exe for debugging purposes')
+        subprocess.call([handle_file])
+      else:
+        _logger.info("Couldn't find %s. Not printing open handles."
+                     % handle_file)
+    raise error