dirs: speed up by storing number of direct children per dir
The Python version of the dirs type stores only the number of direct
children associated with each directory. That means that while adding
a directory, it only has to walk backwards until it runs into a
directory that is already in its map. The C version walks all the way
to the top-most directory. By copying the Python version's clever
trick to the C code, we can speed it up quite a bit.
On the Firefox repo, perfdirs now runs in 0.031390, from 0.056518
before the undoing Sid's optimization in the previous change, and
0.061835 before previous his optimization. More practically, it speeds
up 'hg status nonexistent' on the Firefox repo from 0.176s to 0.155s.
It's unclear why the C version did not have the same cleverness
implemented from the start, especially given that they were both
written by the same person (Bryan O'Sullivan) very close in time:
856960173630 (scmutil: add a dirs class, 2013-04-10)
02ee846b246a (scmutil: rewrite dirs in C, use if available, 2013-04-10)
#!/usr/bin/env python
#
# An example hgweb CGI script, edit as necessary
# See also http://mercurial.selenic.com/wiki/PublishingRepositories
# 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()
from mercurial import demandimport; demandimport.enable()
from mercurial.hgweb import hgweb, wsgicgi
application = hgweb(config)
wsgicgi.launch(application)