Fix regex to parse Variations UI override strings

components/variations/service/generate_ui_string_overrider.py

 #!/usr/bin/python
 # Copyright 2014 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.
 
 import argparse
 import collections
 import hashlib
 import operator
 import os
 import re
 import sys
 
 SCRIPT_NAME = "generate_ui_string_overrider.py"
+

[Raj, 2016/05/12 01:40:27]

The pragma format is defined in
https://code.google.com/p/chromium/codesearch#chromium/src/tools/grit/grit_ru...

+
+# Regular expressions for parsing the #define macro format. Separate regular
+# expressions are used for parsing lines with pragma (for builds with
+# enable_resource_whitelist_generation flag) in windows and non-windows, and for
+# lines without pragma,

[rkaplow, 2016/05/12 01:52:53]

could you give samples for the cases here

[Raj, 2016/05/12 17:03:40]

Done.

 RESOURCE_EXTRACT_REGEX = re.compile('^#define (\S*) (\d*)$', re.MULTILINE)
+RESOURCE_EXTRACT_REGEX_PRAGMA = re.compile(
+      '^#define (\S*) _Pragma\("whitelisted_resource_\d*"\) (\d*)$',

[Alexei Svitkine (slow), 2016/05/12 14:40:41]

Looks like these are defined here:

https://code.google.com/p/chromium/codesearch#chromium/src/build/common.gypi&...

Can you add a comment both to this file referencing those locations and to the
GYPI and GN files referencing this script and mentioning that they have to be
kept in sync.

Also, I wonder if it makes sense to make this Python script fail (causing a
build error) if it found no entries matching the regexes.

[Raj, 2016/05/12 17:03:40]

Sure. I will add the comment in a separate CL. I do not want to wait for another
owner approval, which may delay this CL merge to M51. I just want to keep this
CL small for easy merge. WDYT.

Yes. It is better to fail this script when no entries are found. In fact we
should parse line-by-line and if one line does not match any of the regex, the
script could fail. I will add this in next CL, which may need more testing with
many platforms. WDYT.

+      re.MULTILINE)
+RESOURCE_EXTRACT_REGEX_PRAGMA_WINDOWS = re.compile(

[Raj, 2016/05/12 01:40:27]

Not tested with Windows yet. Will test asap.

[Raj, 2016/05/12 01:47:29]

I tested in linux for android build, that builds with or without
enable_resource_whitelist_generation generate the same
gen/chrome/browser/metrics/variations/ui_string_overrider_factory.cc

+      '^#define (\S*) __pragma\(message\("whitelisted_resource_\d*"\)\) (\d*)$',

[rkaplow, 2016/05/12 01:52:53]

just to verify this isn't a typo - this is lowercase pragma compared to the
other regex?

[Raj, 2016/05/12 17:03:40]

Yes. The pragma format is defined in:
https://code.google.com/p/chromium/codesearch#chromium/src/tools/grit/grit_ru...

+      re.MULTILINE)
 
 class Error(Exception):
   """Base error class for all exceptions in generated_resources_map."""
 
 
 class HashCollisionError(Error):
   """Multiple resource names hash to the same value."""
 
 
 Resource = collections.namedtuple("Resource", ['hash', 'name', 'index'])
@@ skipping 20 matching lines @@
   an iterator over all matching (NAME, INDEX) pairs.
 
   Args:
     string_to_scan: The input string to scan.
 
   Yields:
     A tuple of name and index.
   """
   for match in RESOURCE_EXTRACT_REGEX.finditer(string_to_scan):
     yield match.group(1, 2)
+  for match in RESOURCE_EXTRACT_REGEX_PRAGMA.finditer(string_to_scan):
+    yield match.group(1, 2)
+  for match in RESOURCE_EXTRACT_REGEX_PRAGMA_WINDOWS.finditer(string_to_scan):
+    yield match.group(1, 2)
 
 
 def _GetResourceListFromString(resources_content):
   """Produces a list of |Resource| objects from a string.
 
   The input string contains lines of the form "#define NAME INDEX". The returned
   list is sorted primarily by hash, then name, and then index.
 
   Args:
     resources_content: The input string to process, contains lines of the form
@@ skipping 222 matching lines @@
   with open(os.path.join(
       arguments.output_dir, arguments.source_filename), "w") as generated_file:
     generated_file.write(source_file_content)
   with open(os.path.join(
       arguments.output_dir, arguments.header_filename), "w") as generated_file:
     generated_file.write(header_file_content)
 
 
 if __name__ == '__main__':
   sys.exit(main())