Add tools/licensify.py

tools/licensify.py

@@ -0,0 +1,91 @@
+#!/usr/bin/python
+
+# This script ensures our license header is present on all the files git knows
+# about within the current directory.
+#
+# It is safe to re-run this file on already-processed files.
+
+import os
+import re
+import subprocess
+import shutil
+import tempfile
+
+license = [
+  'Copyright 2016 The Noms Authors. All rights reserved.',
+  'Licensed under the Apache License, version 2.0:',
+  'http://www.apache.org/licenses/LICENSE-2.0',
+]
+
+comment_markers = {
+  'go': ('', '// ', ''),
+  'js': ('', '// ', ''),
+  'py': ('', '# ', ''),
+  'html': ('<!--', '  ', '-->'),
+  'css': ('/**', ' * ', ' */'),
+}
+
+
+def main():
+  files = subprocess.check_output(['git', 'ls-files']).split('\n')
+  for n in files:
+    if n != '' and n.find('vendor/') == -1:
+      _, ext = os.path.splitext(n)
+      if ext == '':
+        continue
+      ext = ext[1:]
+      pattern = buildLicensePattern(ext)
+      if pattern != None:
+        with open(n, 'r+') as f:
+          processFile(f, ext, pattern)
+
+
+# Updates the license block in file |f|.
+def processFile(f, ext, pattern):
+  content = f.read()
+  f.seek(0)
+  f.truncate()
+  replacement = re.sub(pattern, getLicense(ext), content)
+  f.write(replacement)
+
+
+# Builds a regex pattern that matches license blocks in files with extension
+# |ext|.
+def buildLicensePattern(ext):
+  markers = comment_markers.get(ext)
+  if markers is None:
+    return None
+
+  (first, mark, last) = [re.escape(m) for m in markers]
+
+  prefix = ''
+  # The first line must include the copyright string to avoid picking up random
+  # other comment blocks at head of file.
+  head = mark + r'Copyright \d+ The Noms Authors.*\n'
+  body = '(' + mark + r'.*\n)*'
+  suffix = ''
+
+  if first != '':
+    prefix = first + r'\n'
+  if last != '':
+    suffix = last + r'\n'
+
+  # We want to make sure shebang files stay at head of file.
+  shebang = r'(\#\!.+\n\n?|)'
+
+  return '^' + shebang + '(' + prefix + head + body + suffix + r'\n)?'
+
+
+# Gets the license block for files with extension |ext|.
+def getLicense(ext):
+  (first, mark, last) = comment_markers[ext]
+  result = '\n'.join([mark + line for line in license])
+  if first != '':
+    result = first + '\n' + result
+  if last != '':
+    result = result + '\n' + last
+  return r'\g<1>' + result + '\n\n'
+
+
+if __name__ == '__main__':
+  main()