contrib/memory.py

largefiles: port wrapped functions to exthelper

Things get interesting in the commit.  I hadn't seen issue6033 on Windows, and
yet it is now reproducible 100% of the time on Windows 10 with this commit.  I
didn't test Linux.  (For comparison, after seeing this issue, I tested on the
parent with --loop, and it failed 5 times out of over 1300 tests.)

The strange thing is that largefiles has nothing to do with that test (it's not
even mentioned there).  It isn't autoloading run amuck- it occurs even if
largefiles is explicitly disabled, and also if the entry in afterhgrcload() is
commented out.  It's also not the import of lfutil- I disabled that by copying
the function into lfs and removing the import, and the problem still occurs.

Experimenting further, it seems that the problem is isolated to 3 entries:
exchange.pushoperation, hg.clone, and cmdutil.revert.  If those decorators are
all commented out, the test passes when run in a loop for awhile.  (Obviously,
some largefiles tests will fail.)  But if any one is commented back in, the test
fails immediately.

I left one method related to wrapping the wire protocol, because it seemed more
natural with the TODO.  Also, exthelper doesn't support wrapping functions from
another extension, only commands in another extension.  I didn't try to figure
out why rebase is both command wrapped and function wrapped.

# 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)