Make check_gn_headers.py run on Windows

build/check_gn_headers.py

 #!/usr/bin/env python
 # Copyright 2017 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.
 
 """Find header files missing in GN.
 
 This script gets all the header files from ninja_deps, which is from the true
 dependency generated by the compiler, and report if they don't exist in GN.
 """
@@ skipping 34 matching lines @@
     ans = ParseNinjaDepsOutput(NinjaSource(), out_dir)
   except Exception as e:
     err = str(e)
   q.put((ans, err))
 
 
 def ParseNinjaDepsOutput(ninja_out, out_dir):
   """Parse ninja output and get the header files"""
   all_headers = set()
 
-  prefix = '..' + os.sep + '..' + os.sep
+  # Ninja always uses "/", even on Windows.
+  prefix = '../../'
 
   is_valid = False
   for line in ninja_out:
     if line.startswith('    '):
       if not is_valid:
         continue
       if line.endswith('.h') or line.endswith('.hh'):
         f = line.strip()
         if f.startswith(prefix):
           f = f[6:]  # Remove the '../../' prefix
           # build/ only contains build-specific files like build_config.h
           # and buildflag.h, and system header files, so they should be
           # skipped.
           if f.startswith(out_dir) or f.startswith('out'):
             continue
           if not f.startswith('build'):
             all_headers.add(f)
     else:
       is_valid = line.endswith('(VALID)')
 
   return all_headers
 
 
 def GetHeadersFromGN(out_dir, q):
   """Return all the header files from GN"""
 
   tmp = None
   ans, err = set(), None
   try:
-    tmp = tempfile.mkdtemp()
+    # Argument |dir| is needed to make sure it's on the same drive on Windows.
+    # dir='' means dir='.', but doesn't introduce an unneeded prefix.
+    tmp = tempfile.mkdtemp(dir='')
     shutil.copy2(os.path.join(out_dir, 'args.gn'),
                  os.path.join(tmp, 'args.gn'))
     # Do "gn gen" in a temp dir to prevent dirtying |out_dir|.
+    gn_exe = 'gn.bat' if sys.platform == 'win32' else 'gn'
     subprocess.check_call([
-      os.path.join(DEPOT_TOOLS_DIR, 'gn'), 'gen', tmp, '--ide=json', '-q'])
+      os.path.join(DEPOT_TOOLS_DIR, gn_exe), 'gen', tmp, '--ide=json', '-q'])
     gn_json = json.load(open(os.path.join(tmp, 'project.json')))
     ans = ParseGNProjectJSON(gn_json, out_dir, tmp)
   except Exception as e:
     err = str(e)
   finally:
     if tmp:
       shutil.rmtree(tmp)
   q.put((ans, err))
 
 
@@ skipping 15 matching lines @@
             f = out_dir + f[len(tmp_out):]
           all_headers.add(f)
 
   return all_headers
 
 
 def GetDepsPrefixes(q):
   """Return all the folders controlled by DEPS file"""
   prefixes, err = set(), None
   try:
+    gclient_exe = 'gclient.bat' if sys.platform == 'win32' else 'gclient'
     gclient_out = subprocess.check_output([
-      os.path.join(DEPOT_TOOLS_DIR, 'gclient'),
-      'recurse', '--no-progress', '-j1',
-      'python', '-c', 'import os;print os.environ["GCLIENT_DEP_PATH"]'])
+        os.path.join(DEPOT_TOOLS_DIR, gclient_exe),
+        'recurse', '--no-progress', '-j1',
+        'python', '-c', 'import os;print os.environ["GCLIENT_DEP_PATH"]'],
+        universal_newlines=True)
     for i in gclient_out.split('\n'):
       if i.startswith('src/'):
         i = i[4:]
         prefixes.add(i)
   except Exception as e:
     err = str(e)
   q.put((prefixes, err))
 
 
 def IsBuildClean(out_dir):
@@ skipping 124 matching lines @@
   if len(nonexisting) > 0:
     print '\nThe following non-existing files should be removed from gn files:'
     for i in nonexisting:
       print i
 
   return 1
 
 
 if __name__ == '__main__':
   sys.exit(main())