Add a tools to fix the style of new pull requests

scripts/fix_style.py

@@ -0,0 +1,66 @@
+from collections import defaultdict
+import re
+import subprocess
+import sys
+
+RE_POSITION=re.compile(rb"^@@ -[0-9]+,[0-9]+ \+(?P<start>[0-9]+),(?P<len>[0-9]+) @@")
+def get_line_ranges(git_diff):
+	new_filename = None
+	result = defaultdict(list)
+	for line in git_diff.splitlines():
+		if line.startswith(b"+++ "):
+			new_filename = line[6:].decode()
+			continue
+		match = RE_POSITION.match(line)
+		if match:
+			start = int(match.group("start").decode())
+			end = start + int(match.group("len").decode()) - 1
+			result[new_filename].append((start, end))
+			continue
+	return dict(result)
+
+def git_get_changed_lines(margin, base):
+	return get_line_ranges(subprocess.check_output([
+		"git",
+		"diff",
+		base,
+		"--unified={}".format(margin),
+	]))
+
+def filter_cpp(changed_lines):
+	return {filename: changed_lines[filename] for filename in changed_lines
+		if any(filename.endswith(ext) for ext in ".c .cpp .h".split())}
+
+def reformat(changed_lines):
+	for filename in changed_lines:
+		subprocess.check_call(["clang-format", "-i"] + ["--lines={}:{}".format(start, end) for start, end in changed_lines[filename]] + [filename])
+
+def warn(changed_lines):
+	result = 0
+	for filename in changed_lines:
+		result = subprocess.call(["clang-format", "-Werror", "--dry-run"] + ["--lines={}:{}".format(start, end) for start, end in changed_lines[filename]] + [filename]) or result
+	return result
+
+
+def main():
+	import argparse
+	p = argparse.ArgumentParser(description="Check and fix style of changed lines")
+	p.add_argument("--base", default="HEAD", help="Revision to compare to")
+	p.add_argument("-n", "--dry-run", action="store_true", help="Don't fix, only warn")
+	args = p.parse_args()
+	if not args.dry_run:
+		last_ranges = None
+		ranges = filter_cpp(git_get_changed_lines(1, base=args.base))
+		i = 0
+		while last_ranges != ranges:
+			print("Iteration {}".format(i))
+			reformat(ranges)
+			last_ranges = ranges
+			ranges = filter_cpp(git_get_changed_lines(1, base=args.base))
+			i += 1
+		print("Done after {} iterations".format(i))
+	else:
+		sys.exit(warn(filter_cpp(git_get_changed_lines(1, base=args.base))))
+
+if __name__ == "__main__":
+	main()