contrib/memory.py

localrepo: pass root manifest into manifestlog.__init__

Today, localrepository has a method that can be overloaded which
returns an instance of the root manifest storage object. When a
manifestlog is created, it calls this private method and stores
the root manifest object on it.

This "hook" on localrepository isn't part of the documented interface.
It isn't compatible with our desire to make repo storage determined
before the repo object is constructed.

This commit changes manifestlog.__init__ to accept the root
storage object instead of calling into the repo to construct it.
By doing things this way, the repo instance is responsible for
constructing the manifest storage object directly.

This does mean that other derived repo types need to overload
manifestlog(). But they should have been doing this already,
as manifestlog() is typically decorated in a storage-specific way.
e.g. localrepository.manifestlog() is decorated as
@storecache('00manifest.i'). And this assumes that a 00manifest.i
file exists in the store vfs. This condition may not hold for
repository types using non-revlog storage. So it is important
for special repo types to override manifestlog() to remove this
file association.

The code changed in perf is wrong because it isn't compatible with
older Mercurial versions. But I'm pretty sure the code was broken
on older versions before this commit. It only affects `hg perftags`.
I don't care enough to fix that at this time.

.. api::

   ``manifest.manifestlog.__init__()`` now receives the root manifest
   storage instance instead of calling into a private method on
   the repo object to obtain it.

Differential Revision: https://phab.mercurial-scm.org/D4641

# 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)