contrib/memory.py

progress: stop excessive clearing (issue4801)

The progress bar was being cleared on every write(), regardless of
whether it was currently displayed. This could foul up the display of
any writes that didn't include a linebreak.

In particular, the win32 mode of the color extension was turning
single prompt string writes into two writes, and the resulting
clear/write/clear/write pattern was making the prompt invisible.

We fix this by insisting that we have shown a progress bar and haven't
just cleared it (setting lastprint to 0).

Conveniently, the test suite already had instances of duplicate
clears.. that are now cleared up.

# 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
import atexit

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" % (key, value / 1024.0)
                            for key, value in result.iteritems()]) + "\n")

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