pre-commit

#!/bin/env python

import os
import subprocess
import sys

LICENSE = '''\
// Copyright 2020 - developers of the `grammers` project.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
'''

def warn(*args, **kwargs):
	print(*args, **kwargs, file=sys.stderr)

def error(*args, **kwargs):
	warn(*args, **kwargs)
	exit(1)

def check_fmt():
	return subprocess.run(('cargo', '+nightly', 'fmt', '--', '--check')).returncode == 0

def check_fmt_extra():
	ok = True
	for root, _dirs, files in os.walk('.'):
		root = root.replace(os.path.sep, '/')
		if not root.startswith('./grammers'):
			continue
		for file in files:
			if file.lower().endswith('.rs'):
				file = os.path.join(root, file)
				with open(file, 'r', encoding='utf-8') as fd:
					expecting = 0
					was_blank = True
					for line in map(str.strip, fd):
						if not line:
							if was_blank:
								warn(file, 'a single blank lines must be used between groups')
								ok = False
								break
							was_blank = True
						elif was_blank:
							was_blank = False
							if line.startswith('//!'):
								new = 2
							elif line.startswith('///'):
								break
							elif line.startswith('//'):
								new = 1
							elif line.startswith('#!['):
								new = 3
							else:
								break
							if new <= expecting:
								warn(file, 'order must be license comment, doc-comment, cfg, mods/uses')
								break
							expecting = new
						elif expecting == 1:
							if not line.startswith('//'):
								ok = False
								warn(file, 'license comment separated by a single blank line must come first')
								break
						elif expecting == 2:
							if not line.startswith('//!'):
								ok = False
								warn(file, 'doc-comment separated by a single blank line, if any, must come second')
								break
						elif expecting == 3:
							if not line.startswith('#!['):
								ok = False
								warn(file, 'cfg separated by a single blank line, if any, must come third')
								break

	return ok


def check_license():
	ok = True
	for root, _dirs, files in os.walk('.'):
		root = root.replace(os.path.sep, '/')
		if not root.startswith('./grammers'):
			continue
		for file in files:
			if file.lower().endswith('.rs') and not root.endswith('/examples'):
				file = os.path.join(root, file)
				with open(file, 'r', encoding='utf-8') as fd:
					if fd.read(len(LICENSE)) != LICENSE:
						ok = False
						warn(file, 'missing license')
	return ok

def main():
	if not check_fmt():
		error("please run 'cargo +nightly fmt' before commit")

	if not check_license():
		error("please make sure all files have the license header")

	if not check_fmt_extra():
		error("please make sure all files separate their imports")

if __name__ == '__main__':
	main()