contrib/memory.py

log: add an extension hook-point in changeset_printer

Extensions sometimes wants to add other information in the default log output
format (when no templating is used).

Add an empty function named '_exthook' for easing the extension life.
Extensions will be able to wrap this function and collaborate to display
additional information.

Exthook is called after displaying troubles and just before displaying the
files, extra and description.

Add a new test file to test it and not pollute other test files.

# memory.py - track memory usage
#
# Copyright 2009 Matt Mackall <[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.

'''helper extension to measure memory usage

Reads current and peak memory usage from ``/proc/self/status`` and
prints it to ``stderr`` on exit.
'''

from __future__ import absolute_import

def memusage(ui):
    """Report memory usage of the current process."""
    result = {'peak': 0, 'rss': 0}
    with open('/proc/self/status', 'r') as status:
        # This will only work on systems with a /proc file system
        # (like Linux).
        for line in status:
            parts = line.split()
            key = parts[0][2:-1].lower()
            if key in result:
                result[key] = int(parts[1])
    ui.write_err(", ".join(["%s: %.1f MiB" % (k, v / 1024.0)
                            for k, v in result.iteritems()]) + "\n")

def extsetup(ui):
    ui.atexit(memusage, ui)