Add support for fix-header: skip, to ignore a file

Comment formats supported:
#
/* */
//

scripts/tools/fix-header.py

@@ -28,6 +28,7 @@ import itertools
 import os
 import re
 import subprocess  # nosec: B404
+import sys
 
 
 ALIASES = {
@@ -113,6 +114,7 @@ def parse_file(path):
     start = end = None
     authors_from_file = {}
 
+    skip_pattern = re.compile(r'^(?:#|/\*|//)\s+(fix-header:\s*skip|Automatically\s+generated)', re.IGNORECASE)
     with open(path) as f:
         lines = f.readlines()
         found = defaultdict(lambda: None)
@@ -120,8 +122,9 @@ def parse_file(path):
             found["shebang"] = lines[0].rstrip()
             del lines[0]
         for num, line in enumerate(lines):
-            if line.startswith("# Automatically generated"):
-                found['autogenerated'] = num
+            match = skip_pattern.search(line)
+            if match:
+                found['skip'] = match.group(1)
                 return (found, {}, {}, '', "".join(lines))
 
         for num, line in enumerate(lines):
@@ -206,8 +209,8 @@ LICENSE_BOTTOM = """#
 
 def fix_header(path):
     found, authors_from_file, authors_from_log, before, after = parse_file(path)
-    if found['autogenerated'] is not None:
-        return None
+    if found['skip'] is not None:
+        return None, found['skip']
 
     authors = {}
     for a in authors_from_log:
@@ -245,7 +248,7 @@ def fix_header(path):
         before.strip(),
         after.strip(),
     ]))
-    return "\n".join(parts)
+    return "\n".join(parts), None
 
 
 def main():
@@ -269,10 +272,14 @@ def main():
         else:
             if args.recursive:
                 paths += glob.glob(path + '/*')
+    if not files:
+        print("No valid file found", file=sys.stderr)
+        sys.exit(0)
 
     for path in files:
-        new_content = fix_header(path)
+        new_content, info = fix_header(path)
         if new_content is None:
+            print("Skipping %s (%s)" % (path, info), file=sys.stderr)
             continue
         if args.in_place:
             with open(path, 'w') as f: