Add support for JSON output to checklicenses.py

tools/checklicenses/checklicenses.py

 #!/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.
 
 """Makes sure that all files contain proper licensing information."""
 
 
+import json
 import optparse
 import os.path
 import subprocess
 import sys
 
 
 def PrintUsage():
   print """Usage: python checklicenses.py [--root <root>] [tocheck]
   --root   Specifies the repository root. This defaults to "../.." relative
            to the script file. This will be correct given the normal location
@@ skipping 396 matching lines @@
     print stdout
     print '--------- end licensecheck stdout ---------'
   if licensecheck.returncode != 0 or stderr:
     print '----------- licensecheck stderr -----------'
     print stderr
     print '--------- end licensecheck stderr ---------'
     print "\nFAILED\n"
     return 1
 
   used_suppressions = set()
+  errors = []
 
-  success = True
   for line in stdout.splitlines():
     filename, license = line.split(':', 1)
     filename = os.path.relpath(filename.strip(), options.base_directory)
 
     # All files in the build output directory are generated one way or another.
     # There's no need to check them.
     if filename.startswith('out/'):
       continue
 
     # For now we're just interested in the license.
     license = license.replace('*No copyright*', '').strip()
 
     # Skip generated files.
     if 'GENERATED FILE' in license:
       continue
 
     if license in WHITELISTED_LICENSES:
       continue
 
     if not options.ignore_suppressions:
       matched_prefixes = [
           prefix for prefix in PATH_SPECIFIC_WHITELISTED_LICENSES
           if filename.startswith(prefix) and
           license in PATH_SPECIFIC_WHITELISTED_LICENSES[prefix]]
       if matched_prefixes:
         used_suppressions.update(set(matched_prefixes))
         continue
 
-    print "'%s' has non-whitelisted license '%s'" % (filename, license)
-    success = False
+    errors.append({'filename': filename, 'license': license})
 
-  if success:
-    print "\nSUCCESS\n"
+  if options.json:
+    with open(options.json, 'w') as f:
+      json.dump(errors, f)
 
-    if not len(args):
-      unused_suppressions = set(
-        PATH_SPECIFIC_WHITELISTED_LICENSES.keys()).difference(used_suppressions)
-      if unused_suppressions:
-        print "\nNOTE: unused suppressions detected:\n"
-        print '\n'.join(unused_suppressions)
-
-    return 0
-  else:
+  if errors:
+    for error in errors:
+      print "'%s' has non-whitelisted license '%s'" % (
+          error['filename'], error['license'])
     print "\nFAILED\n"
     print "Please read",
     print "http://www.chromium.org/developers/adding-3rd-party-libraries"
     print "for more info how to handle the failure."
     print
     print "Please respect OWNERS of checklicenses.py. Changes violating"
     print "this requirement may be reverted."
 
     # Do not print unused suppressions so that above message is clearly
     # visible and gets proper attention. Too much unrelated output
     # would be distracting and make the important points easier to miss.
 
     return 1
 
+  print "\nSUCCESS\n"
+
+  if not len(args):
+    unused_suppressions = set(
+        PATH_SPECIFIC_WHITELISTED_LICENSES.iterkeys()).difference(
+            used_suppressions)
+    if unused_suppressions:
+      print "\nNOTE: unused suppressions detected:\n"
+      print '\n'.join(unused_suppressions)
+
+  return 0
+
 
 def main():
   default_root = os.path.abspath(
       os.path.join(os.path.dirname(__file__), '..', '..'))
   option_parser = optparse.OptionParser()
   option_parser.add_option('--root', default=default_root,
                            dest='base_directory',
                            help='Specifies the repository root. This defaults '
                            'to "../.." relative to the script file, which '
                            'will normally be the repository root.')
   option_parser.add_option('-v', '--verbose', action='store_true',
                            default=False, help='Print debug logging')
   option_parser.add_option('--ignore-suppressions',
                            action='store_true',
                            default=False,
                            help='Ignore path-specific license whitelist.')
+  option_parser.add_option('--json', help='Path to JSON output file')
   options, args = option_parser.parse_args()
   return check_licenses(options, args)
 
 
 if '__main__' == __name__:
   sys.exit(main())