view contrib/memory.py @ 25365:4cc3fb23881d

hg: explicitly check that peer lookup object has instance() if call failed

If a "thing" is callable but raises TypeError for some reason, a callable
object would be returned. Thereafter, unfriendly traceback would be displayed:

  Traceback (most recent call last):
    ...
    File "mercurial/hg.pyc", line 119, in _peerorrepo
      obj = _peerlookup(path).instance(ui, path, create)
  AttributeError: 'function' object has no attribute 'instance'

Instead, we should show the reason why "thing(path)" didn't work:

  Traceback (most recent call last):
    ...
    File "hggit/__init__.py", line 89, in _local
      p = urlcls(path).localpath()
  TypeError: 'NoneType' object is not callable

If a "thing" is not callable, it must be a module or an object that implements
instance(). If that module didn't have instance(), the error message would be
"<unloaded module 'foo'> object is not callable". It doesn't make perfect sense,
but it isn't so bad as it can blame which module went wrong.

# 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.
'''

import atexit

def memusage(ui):
    """Report memory usage of the current process."""
    status = None
    result = {'peak': 0, 'rss': 0}
    try:
        # This will only work on systems with a /proc file system
        # (like Linux).
        status = open('/proc/self/status', 'r')
        for line in status:
            parts = line.split()
            key = parts[0][2:-1].lower()
            if key in result:
                result[key] = int(parts[1])
    finally:
        if status is not None:
            status.close()
    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)