MD WebUI: Strip comments from vulcanized JS files

chrome/browser/resources/vulcanize.py

 #!/usr/bin/env python
 # Copyright 2016 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 os
+import re
 import subprocess
 import sys
 import tempfile
 
 # See //docs/vulcanize.md for instructions on installing prerequistes and
 # running the vulcanize build.
 
 _HERE_PATH = os.path.join(os.path.dirname(__file__))
 _SRC_PATH = os.path.normpath(os.path.join(_HERE_PATH, '..', '..', '..'))
 
@@ skipping 25 matching lines @@
   '--redirect', 'chrome://resources/cr_elements/|%s' % _CR_ELEMENTS_PATH,
   '--redirect', 'chrome://resources/css/|%s' % _CSS_RESOURCES_PATH,
   '--redirect', 'chrome://resources/html/|%s' % _HTML_RESOURCES_PATH,
   '--redirect', 'chrome://resources/js/|%s' % _JS_RESOURCES_PATH,
   '--redirect', 'chrome://resources/polymer/v1_0/|%s' % _POLYMER_PATH,
 
   '--strip-comments',
 ]
 
 
+def _strip_js_comments(filename):
+  start_comment = re.compile(r'^ */\*\*?$')
+  end_comment = re.compile(r'^ *\*\*?/$')
+  single_line_comment = re.compile(r'^ *//')
+  keep_comment = re.compile(r'Copyright|license|LICENSE|\<\/?if')

[michaelpg, 2016/08/17 07:39:56]

ugh, grit works inside comments? what about
    // <include

[tsergeant, 2016/08/17 07:57:52]

The commented-if is used in one place in util.js. You can check with dbeam for
why it is commented out.

Includes have already been explicitly disabled by this stage so they don't need
to be handled here.

+
+  with open(filename) as f:
+    contents = f.readlines()
+
+  out_lines = []
+  inside_comment = False
+
+  for line in contents:
+    if not inside_comment:
+      if start_comment.match(line):
+        inside_comment = True
+      elif not single_line_comment.match(line) or keep_comment.search(line):
+        out_lines.append(line)
+    elif end_comment.match(line):
+      inside_comment = False
+
+  with open(filename, 'w') as f:
+    f.writelines(out_lines)
+
+
 def _vulcanize(directory, host, html_in_file, html_out_file='vulcanized.html',
                js_out_file='crisper.js', extra_args=None):
   def _run_cmd(cmd_parts, stdout=None):
     cmd = "'" + "' '".join(cmd_parts) + "'"
     process = subprocess.Popen(
         cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)
     stdout, stderr = process.communicate()
 
     if stderr:
       print >> sys.stderr, '%s failed: %s' % (cmd, stderr)
@@ skipping 16 matching lines @@
   with tempfile.NamedTemporaryFile(mode='wt+', delete=False) as tmp:
     # Grit includes are not supported, use HTML imports instead.
     tmp.write(output.replace(
         '<include src="', '<include src-disabled="'))
 
   try:
     _run_cmd(['crisper', '--source', tmp.name,
                          '--script-in-head', 'false',
                          '--html', html_out_path,
                          '--js', js_out_path])
+
+    _strip_js_comments(js_out_path)
   finally:
     os.remove(tmp.name)
 
 
 def main():
   _vulcanize(directory='md_downloads', host='downloads',
              html_in_file='downloads.html')
 
   # Already loaded by history.html:
   history_extra_args = ['--exclude', 'chrome://resources/html/util.html',
                         '--exclude', 'chrome://history/constants.html']
   _vulcanize(directory='md_history', host='history', html_in_file='app.html',
              html_out_file='app.vulcanized.html', js_out_file='app.crisper.js',
              extra_args=history_extra_args)
 
 
 if __name__ == '__main__':
   main()