contrib/hgweb.wsgi

context: get filesadded() and filesremoved() from changeset if configured

This adds the read side for getting the sets of added and removed
files from the changeset extras. I timed this command on the hg repo:

  hg log -T '{rev}\n {files}\n %:{file_mods}\n +{file_adds}\n -{file_dels}\n'

It took 1m21s before and 6.4s after. I also used that command to check
that the result didn't change compared to calculating the values from
the manifests on the fly (it didn't change).

In the mozilla-unified repo, the same command run on
FIREFOX_BETA_58_END::FIREFOX_BETA_59_END went from 29s to 0.67s.

Differential Revision: https://phab.mercurial-scm.org/D6417

# An example WSGI for use with mod_wsgi, edit as necessary
# See https://mercurial-scm.org/wiki/modwsgi for more information

# Path to repo or hgweb config to serve (see 'hg help hgweb')
config = "/path/to/repo/or/config"

# Uncomment and adjust if Mercurial is not installed system-wide
# (consult "installed modules" path from 'hg debuginstall'):
#import sys; sys.path.insert(0, "/path/to/python/lib")

# Uncomment to send python tracebacks to the browser if an error occurs:
#import cgitb; cgitb.enable()

# enable demandloading to reduce startup time
from mercurial import demandimport; demandimport.enable()

from mercurial.hgweb import hgweb
application = hgweb(config)