make `python build/vs_toolchain.py update` work a bit better on non-windows

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 30 matching lines @@
 BASEDIR = os.path.dirname(os.path.abspath(__file__))
 DEPOT_TOOLS_PATH = os.path.join(BASEDIR, '..')
 sys.path.append(DEPOT_TOOLS_PATH)
 try:
   import download_from_google_storage
 except ImportError:
   # Allow use of utility functions in this script from package_from_installed
   # on bare VM that doesn't have a full depot_tools.
   pass
 
-if sys.platform != 'cygwin':
+if sys.platform == 'win32':
   import ctypes.wintypes
   GetFileAttributes = ctypes.windll.kernel32.GetFileAttributesW
   GetFileAttributes.argtypes = (ctypes.wintypes.LPWSTR,)
   GetFileAttributes.restype = ctypes.wintypes.DWORD

[Nico, 2015/06/12 05:29:05]

This won't work on non-win…

   FILE_ATTRIBUTE_HIDDEN = 0x2
   FILE_ATTRIBUTE_SYSTEM = 0x4
 
-
 def IsHidden(file_path):
   """Returns whether the given |file_path| has the 'system' or 'hidden'
   attribute set."""
+  if sys.platform != 'win32':
+    return False

[Nico, 2015/06/12 05:29:05]

…so I have to do this, which means the hashes will never match and I have to
download 500 MB each time I run `python build/vs_toolchain.py update`

[scottmg, 2015/06/12 16:59:12]

I had forgotten why. The long ago rationale was here:

https://codereview.chromium.org/95983002#msg5

It doesn't seem that important, but maybe occasionally confusing for a Windows
user that pokes around in that directory and then it gets nuked.

But otoh, 

d:\src\depot_tools\win_toolchain\vs_files>attrib /s | grep -v "A            "

returned nothing. So, I'm not sure. Maybe I'm unzipping wrong as of recently (I
changed from 7z to python zipfile) or maybe there's none anyway? You're sure
this is why the hash doesn't match?

[Nico, 2015/06/12 17:04:29]

No, I just saw that the hash didn't match and figured it's probably this. I'll
check if running the update command on my Windows box tries to redownload if I
always return False here when I'm back near a Windows box (monday)

   p = GetFileAttributes(file_path)
   assert p != 0xffffffff
   return bool(p & (FILE_ATTRIBUTE_HIDDEN | FILE_ATTRIBUTE_SYSTEM))
 
 
 def GetFileList(root):
   """Gets a normalized list of files under |root|."""
   assert not os.path.isabs(root)
   assert os.path.normpath(root) == root

[scottmg, 2015/06/12 16:59:12]

It seems like posix.normpath vs. nt.normpath might cause problems too?

   file_list = []
   for base, _, files in os.walk(root):
     paths = [os.path.join(base, f) for f in files]
     file_list.extend(x.lower() for x in paths if not IsHidden(x))
   return sorted(file_list)
 
 
 def MakeTimestampsFileName(root):
   return os.path.join(root, '..', '.timestamps')
 
@@ skipping 55 matching lines @@
       return True
     return subprocess.call(
         ['git', '-c', 'core.askpass=true', 'remote', 'show',
          'https://chrome-internal.googlesource.com/chrome/src-internal/'],
         shell=True, stdin=nul, stdout=nul, stderr=nul) == 0
 
 
 def LooksLikeGoogler():
   """Checks for a USERDOMAIN environment variable of 'GOOGLE', which
   probably implies the current user is a Googler."""
-  return os.environ.get('USERDOMAIN').upper() == 'GOOGLE'
+  return os.environ.get('USERDOMAIN', '').upper() == 'GOOGLE'
 
 
 def CanAccessToolchainBucket():
   """Checks whether the user has access to gs://chrome-wintoolchain/."""
   gsutil = download_from_google_storage.Gsutil(
       download_from_google_storage.GSUTIL_DEFAULT_PATH, boto_path=None)
   code, _, _ = gsutil.check_call('ls', 'gs://chrome-wintoolchain/')
   return code == 0
 
 
@@ skipping 51 matching lines @@
 def DoTreeMirror(target_dir, tree_sha1):
   """In order to save temporary space on bots that do not have enough space to
   download ISOs, unpack them, and copy to the target location, the whole tree
   is uploaded as a zip to internal storage, and then mirrored here."""
   temp_dir, local_zip = DownloadUsingGsutil(tree_sha1 + '.zip')
   sys.stdout.write('Extracting %s...\n' % local_zip)
   sys.stdout.flush()
   with zipfile.ZipFile(local_zip, 'r', zipfile.ZIP_DEFLATED, True) as zf:
     zf.extractall(target_dir)
   if temp_dir:
-    subprocess.check_call('rmdir /s/q "%s"' % temp_dir, shell=True)
+    shutil.rmtree(temp_dir, ignore_errors=True)

[scottmg, 2015/06/12 16:59:12]

This function is terrible, and fails for files marked readonly on Windows, which
there are (were?) in the toolchain. It's possible only with the
old-Express-from-bits path, not the google extraction path though.

[Nico, 2015/06/12 17:04:29]

TIL! Could the onerror handler in the first reply in
http://stackoverflow.com/questions/2656322/python-shutil-rmtree-fails-on-wind...
work?

[scottmg, 2015/06/12 17:13:56]

Looks like it, but it seems longer than an if win: rmdir else: rmtree function.
/shrug

 
 
 def main():
-  if not sys.platform.startswith(('cygwin', 'win32')):
-    return 0
+  #if not sys.platform.startswith(('cygwin', 'win32')):
+    #return 0
 
   parser = optparse.OptionParser(description=sys.modules[__name__].__doc__)
   parser.add_option('--output-json', metavar='FILE',
                     help='write information about toolchain to FILE')
   options, args = parser.parse_args()
 
   if sys.platform == 'cygwin':
     # This script requires Windows Python, so invoke with depot_tools' Python.
     def winpath(path):
       return subprocess.check_output(['cygpath', '-w', path]).strip()
@@ skipping 38 matching lines @@
       print('Please follow the instructions at '
             'http://www.chromium.org/developers/how-tos/'
             'build-instructions-windows')
       return 1
     print('Windows toolchain out of date or doesn\'t exist, updating (Pro)...')
     print('  current_hash: %s' % current_hash)
     print('  desired_hashes: %s' % ', '.join(desired_hashes))
     sys.stdout.flush()
     DelayBeforeRemoving(target_dir)
     # This stays resident and will make the rmdir below fail.
-    with open(os.devnull, 'wb') as nul:
-      subprocess.call(['taskkill', '/f', '/im', 'mspdbsrv.exe'],
-                      stdin=nul, stdout=nul, stderr=nul)
+    if sys.platform in ('win32', 'cygwin'):
+      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)
+      shutil.rmtree(target_dir, ignore_errors=True);
 
     DoTreeMirror(target_dir, desired_hashes[0])
 
     got_new_toolchain = True
 
   win_sdk = os.path.join(abs_target_dir, 'win_sdk')
   try:
     with open(os.path.join(target_dir, 'VS_VERSION'), 'rb') as f:
       vs_version = f.read().strip()
   except IOError:
@@ skipping 29 matching lines @@
 
   if options.output_json:
     shutil.copyfile(os.path.join(target_dir, '..', 'data.json'),
                     options.output_json)
 
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main())