patch: stop using cext.diffhelpers
The C implementation has a couple of memory bugs, and lacks error handling
which could lead to SEGV. I could fix them one by one (and I mostly finished
that), but the performance gain provided by cext.diffhelper is quite low.
Besides, diffhelpers.addlines() calls back Python, linereader.readline(),
from the innermost loop.
$ hg export -R mozilla-central 0:100 > patch
$ ls -lh patch
-rw-r--r-- 184M patch
$ hg init repo && hg -R repo import patch --time --bypass
(cext) time: real 34.970 secs (user 32.720+0.000 sys 2.230+0.000)
(pure) time: real 35.950 secs (user 33.600+0.000 sys 2.330+0.000)
So, let's simply use the pure Python implementation.
Mercurial's documentation is kept in reStructuredText format, which is
a simple plain text format that's easy to read and edit:
http://docutils.sourceforge.net/rst.html
It's also convertible to a variety of other formats including standard
UNIX man page format and HTML. You'll need to install Docutils:
http://docutils.sourceforge.net/
Use the Makefile in this directory to generate the man and HTML pages.