Add retries for deletion on Windows.

build_apprtc_collider.py

 #!/usr/bin/python
 # Copyright 2014 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.
 
 """Builds the AppRTC collider using the golang toolchain.
 
 The golang toolchain is downloaded by download_golang.py. We use that here
 to build the AppRTC collider server.
 """
 
 import os
 import shutil
 import subprocess
 import sys
+import time
 
 import utils
 
 
+# Code partially copied from
+# https://cs.chromium.org#chromium/build/scripts/common/chromium_utils.py
+def RemoveDirectory(*path):
+  """Recursively removes a directory, even if it's marked read-only.
+
+  Remove the directory located at *path, if it exists.
+
+  shutil.rmtree() doesn't work on Windows if any of the files or directories
+  are read-only, which svn repositories and some .svn files are.  We need to
+  be able to force the files to be writable (i.e., deletable) as we traverse
+  the tree.
+
+  Even with all this, Windows still sometimes fails to delete a file, citing
+  a permission error (maybe something to do with antivirus scans or disk
+  indexing).  The best suggestion any of the user forums had was to wait a
+  bit and try again, so we do that too.  It's hand-waving, but sometimes it
+  works. :/
+  """
+  file_path = os.path.join(*path)
+  if not os.path.exists(file_path):
+    return
+
+  if sys.platform == 'win32':
+    # Give up and use cmd.exe's rd command.
+    file_path = os.path.normcase(file_path)
+    for _ in xrange(3):
+      print 'RemoveDirectory running %s' % (' '.join(
+          ['cmd.exe', '/c', 'rd', '/q', '/s', file_path]))
+      if not subprocess.call(['cmd.exe', '/c', 'rd', '/q', '/s', file_path]):
+        break
+      print '  Failed'
+      time.sleep(3)
+    return
+  else:
+    shutil.rmtree(file_path, ignore_errors=True)
+
+
 def main():
   apprtc_dir = os.path.join('apprtc', 'src')
   golang_workspace = os.path.join('src', 'out', 'go-workspace')
-  shutil.rmtree(golang_workspace, ignore_errors=True)
+  RemoveDirectory(golang_workspace)
+
   golang_workspace_src = os.path.join(golang_workspace, 'src')
 
   collider_dir = os.path.join(apprtc_dir, 'collider')
   shutil.copytree(collider_dir, golang_workspace_src,
                   ignore=shutil.ignore_patterns('.svn', '.git'))
 
   golang_binary = 'go%s' % ('.exe' if utils.GetPlatform() == 'win' else '')
   golang_path = os.path.join('go', 'bin', golang_binary)
 
   golang_env = os.environ.copy()
   golang_env['GOROOT'] = os.path.abspath('go')
   golang_env['GOPATH'] = os.path.abspath(golang_workspace)
   golang_env['PATH'] += os.pathsep + os.path.abspath('mercurial')
   subprocess.check_call([golang_path, 'get', 'collidermain'],
                         env=golang_env)
   subprocess.check_call([golang_path, 'build', 'collidermain'],
                         env=golang_env)
 
 if __name__ == '__main__':
   sys.exit(main())
+