win_toolchain: add timeout before nuke, hide taskkill output

win_toolchain/get_toolchain_if_necessary.py

 #!/usr/bin/env python
 # Copyright 2013 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.
 
 """Downloads and unpacks a toolchain for building on Windows. The contents are
 matched by sha1 which will be updated when the toolchain is updated.
 
 Having a toolchain script in depot_tools means that it's not versioned
 directly with the source code. That is, if the toolchain is upgraded, but
@@ skipping 14 matching lines @@
 future when a hypothetical VS2015 is released, the 2013 script will be
 maintained, and a new 2015 script would be added.
 """
 
 import ctypes.wintypes
 import hashlib
 import json
 import os
 import subprocess
 import sys
+import time
 
 
 BASEDIR = os.path.dirname(os.path.abspath(__file__))
 
 
 GetFileAttributes = ctypes.windll.kernel32.GetFileAttributesW
 GetFileAttributes.argtypes = (ctypes.wintypes.LPWSTR,)
 GetFileAttributes.restype = ctypes.wintypes.DWORD
 FILE_ATTRIBUTE_HIDDEN = 0x2
 FILE_ATTRIBUTE_SYSTEM = 0x4
@@ skipping 76 matching lines @@
         ['svn', 'ls',
          'svn://svn.chromium.org/chrome-internal/trunk/src-internal/'],
         shell=True, stdin=nul, stdout=nul, stderr=nul) == 0:
       return True
     return subprocess.call(
         ['git', 'remote', 'show',
          'https://chrome-internal.googlesource.com/chrome/src-internal/'],
         shell=True, stdin=nul, stdout=nul, stderr=nul) == 0
 
 
+def DelayBeforeRemoving(target_dir):
+  """A grace period before deleting the out of date toolchain directory."""
+  if (os.path.isdir(target_dir) and
+      not bool(int(os.environ.get('CHROME_HEADLESS', '0')))):
+    for i in range(9, 0, -1):
+      sys.stdout.write(
+              '\rRemoving old toolchain in %ds... (Ctrl-C to cancel)' % i)
+      sys.stdout.flush()
+      time.sleep(1)
+    print
+
+
 def main():
   if not sys.platform.startswith(('cygwin', 'win32')):
     return 0
 
   if len(sys.argv) != 1:
     print >> sys.stderr, 'Unexpected arguments.'
     return 1
 
   # Move to depot_tools\win_toolchain where we'll store our files, and where
   # the downloader script is.
@@ skipping 10 matching lines @@
   # If the current hash doesn't match what we want in the file, nuke and pave.
   # Typically this script is only run when the .sha1 one file is updated, but
   # directly calling "gclient runhooks" will also run it, so we cache
   # based on timestamps to make that case fast.
   current_hash = CalculateHash(target_dir)
   if current_hash not in desired_hashes:
     should_get_pro = (os.path.isfile(os.path.join(BASEDIR, '.vspro')) or
                       HaveSrcInternalAccess())
     print('Windows toolchain out of date or doesn\'t exist, updating (%s)...' %
           ('Pro' if should_get_pro else 'Express'))
+    print('  current_hash: %s' % current_hash)
+    print('  desired_hashes: %s' % desired_hashes)
+    DelayBeforeRemoving(target_dir)
     # This stays resident and will make the rmdir below fail.
-    subprocess.call(['taskkill', '/f', '/im', 'mspdbsrv.exe'])
+    with open(os.devnull, 'wb') as nul:
+      subprocess.call(['taskkill', '/f', '/im', 'mspdbsrv.exe'],
+                      stdin=nul, stdout=nul, stderr=nul)
     if os.path.isdir(target_dir):
       subprocess.check_call('rmdir /s/q "%s"' % target_dir, shell=True)
     args = [sys.executable,
             'toolchain2013.py',
             '--targetdir', target_dir]
     if not should_get_pro:
       args.append('--express')
     subprocess.check_call(args)
     current_hash = CalculateHash(target_dir)
     if current_hash not in desired_hashes:
       print >> sys.stderr, (
           'Got wrong hash after pulling a new toolchain. '
           'Wanted one of \'%s\', got \'%s\'.' % (
               desired_hashes, current_hash))
       return 1
     SaveTimestampsAndHash(target_dir, current_hash)
 
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main())