doc/docchecker

revlog: filter out "invalid" delta base candidates

There are bases that we know won't produce a good delta chain. For example, if
the base is already bigger than twice the size of the text we store, we know
the resulting delta chain will never be valid.

We might make the check a bit more powerful and generic in the future, but
this looks a good start.

In particular, empty file (size 0) will never find a good base, so we should
stop spending time trying to find one.

#!/usr/bin/env python
#
# docchecker - look for problematic markup
#
# Copyright 2016 timeless <[e-mail]> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import, print_function

import re
import sys

leadingline = re.compile(r'(^\s*)(\S.*)$')

checks = [
  (r""":hg:`[^`]*'[^`]*`""",
    """warning: please avoid nesting ' in :hg:`...`"""),
  (r'\w:hg:`',
    'warning: please have a space before :hg:'),
  (r"""(?:[^a-z][^'.])hg ([^,;"`]*'(?!hg)){2}""",
    '''warning: please use " instead of ' for hg ... "..."'''),
]

def check(line):
    messages = []
    for match, msg in checks:
        if re.search(match, line):
            messages.append(msg)
    if messages:
        print(line)
        for msg in messages:
            print(msg)

def work(file):
    (llead, lline) = ('', '')

    for line in file:
        # this section unwraps lines
        match = leadingline.match(line)
        if not match:
            check(lline)
            (llead, lline) = ('', '')
            continue

        lead, line = match.group(1), match.group(2)
        if (lead == llead):
            if (lline != ''):
                lline += ' ' + line
            else:
                lline = line
        else:
            check(lline)
            (llead, lline) = (lead, line)
    check(lline)

def main():
    for f in sys.argv[1:]:
        try:
            with open(f) as file:
                work(file)
        except BaseException as e:
            print("failed to process %s: %s" % (f, e))

main()