hgweb.cgi

Teach walk code about absolute paths.

The first consequence of this is that absolute and relative paths now
all work in the same way.  The second is that paths that lie outside
the repository now cause an error to be reported, instead of something
arbitrary and expensive being done.

Internally, all of the serious work is in the util package.  The new
canonpath function takes an arbitrary path and either returns a
canonical path or raises an error.  Because it needs to know where the
repository root is, it must be fed a repository or dirstate object, which
has given commands.matchpats and friends a new parameter to pass along.

The util.matcher function uses this to canonicalise globs and relative
path names.

Meanwhile, I've moved the Abort exception from commands to util, and
killed off the redundant util.CommandError exception.

#!/usr/bin/env python
#
# An example CGI script to use hgweb, edit as necessary

import cgitb, os, sys
cgitb.enable()

# sys.path.insert(0, "/path/to/python/lib") # if not a system-wide install
from mercurial import hgweb

h = hgweb.hgweb("/path/to/repo", "repository name")
h.run()