gyp_chromium: Better parsing of -G command line flag.

build/gyp_chromium

 #!/usr/bin/env python
 
 # Copyright (c) 2012 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.
 
 # This script is wrapper for Chromium that adds some support for how GYP
 # is invoked by Chromium beyond what can be done in the gclient hooks.
 
 import glob
@@ skipping 124 matching lines @@
         cmdline_input_items += [sys.argv[i][2:]]
   cmdline_items = ProcessGypDefinesItems(cmdline_input_items)
 
   vars_dict = dict(supp_items + env_items + cmdline_items)
   return vars_dict
 
 
 def GetOutputDirectory():
   """Returns the output directory that GYP will use."""
   # GYP generator flags from the command line. We can't use optparse since we
   # want to ignore all arguments other than "-G".

[scottmg, 2015/02/03 00:21:32]

I'm a little skeptical of this comment (though since you cc'd me, maybe I was
the author of it...)

Since the function's getting a bit long, could you do something like
http://stackoverflow.com/questions/1885161/how-can-i-get-optparses-optionpars...
instead to more closely match what gyp is going to do?

[Sam Clegg, 2015/02/03 01:20:10]

Done.

-  needle = '-Goutput_dir='
-  cmdline_input_items = []
+  flag = '-G'
+  found_flag = False
+  needle = 'output_dir='
   for item in sys.argv[1:]:
-    if item.startswith(needle):
-      return item[len(needle):]
+    if item == flag:
+      found_flag = True
+      continue
+
+    # Handle the two flag case (['-G', 'output_dir=foo'])
+    if found_flag:
+      found_flag = False
+      if item.startswith(needle):
+        return item[len(needle):]
+      continue
+
+    # Handle the single flag case (['-Goutput_dir=foo'])
+    if item.startswith(flag):
+      item = item[len(flag):]
+      if item.startswith(needle):
+        return item[len(needle):]
 
   env_items = shlex.split(os.environ.get('GYP_GENERATOR_FLAGS', ''))
   needle = 'output_dir='
   for item in env_items:
     if item.startswith(needle):
       return item[len(needle):]
 
-  return "out"
+  return 'out'
 
 
 def additional_include_files(supplemental_files, args=[]):
   """
   Returns a list of additional (.gypi) files to include, without duplicating
   ones that are already specified on the command line. The list of supplemental
   include files is passed in as an argument.
   """
   # Determine the include files specified on the command line.
   # This doesn't cover all the different option formats you can use,
@@ skipping 157 matching lines @@
 
   if not use_analyzer:
     vs2013_runtime_dll_dirs = vs_toolchain.SetEnvironmentAndGetRuntimeDllDirs()
     if vs2013_runtime_dll_dirs:
       x64_runtime, x86_runtime = vs2013_runtime_dll_dirs
       vs_toolchain.CopyVsRuntimeDlls(
         os.path.join(chrome_src, GetOutputDirectory()),
         (x86_runtime, x64_runtime))
 
   sys.exit(gyp_rc)