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

win_toolchain/get_toolchain_if_necessary.py

Index: win_toolchain/get_toolchain_if_necessary.py
diff --git a/win_toolchain/get_toolchain_if_necessary.py b/win_toolchain/get_toolchain_if_necessary.py
index b06daf6c53f516647bb23e3b593e040165530236..9f434cc7468e47a2d59239e4471d4e42cdae8ce7 100755
--- a/win_toolchain/get_toolchain_if_necessary.py
+++ b/win_toolchain/get_toolchain_if_necessary.py
@@ -48,7 +48,7 @@ except ImportError:
   # 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,)
@@ -56,10 +56,11 @@ if sys.platform != 'cygwin':
   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))
@@ -144,7 +145,7 @@ def HaveSrcInternalAccess():
 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():
@@ -216,12 +217,12 @@ def DoTreeMirror(target_dir, tree_sha1):
   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',
@@ -280,11 +281,12 @@ def main():
     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])