profile: upgrade the "profile" context manager to a full class
So far we have been able to use a simple decorator for this. However using the
current context manager makes the scope of the profiling in dispatch
constrainted and the time frame to decide to enable profiling quite limited
(using "maybeprofile")
This is the first step toward the ability to enable the profiling from within
the profiling scope. eg::
with maybeprofiling(ui) as profiler:
...
bar.foo():
...
if options['profile']:
profiler.start()
...
fooz()
...
My target usecase is adding support for "--profile" to alias definitions with
effect. These are to be used with "profiling.output=blackbox" to gather data
about operation that get slow from time to time (eg: pull being minutes instead
of seconds from time to time).
Of course, in such case, the scope of the profiling would be smaller since
profiler would be started after running extensions 'reposetup' (and other
potentially costly logic), but these are not relevant for my target usecase
(multiple second commits, multiple tens of seconds pull).
Currently adding '--profile' to a command through alias requires to re-spin a
Mercurial binary (using "!$HG" in alias), which as a significant performance
impact, especially in context where startup performance is being worked on...
An alternative approach would be to stop using the context manager in dispatch
and move back to a try/finally setup.
#!/usr/bin/env python
# fixpax - fix ownership in bdist_mpkg output
#
# Copyright 2015 Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms of the
# MIT license (http://opensource.org/licenses/MIT)
"""Set file ownership to 0 in an Archive.pax.gz.
Suitable for fixing files bdist_mpkg output:
*.mpkg/Contents/Packages/*.pkg/Contents/Archive.pax.gz
"""
from __future__ import absolute_import, print_function
import gzip
import os
import sys
def fixpax(iname, oname):
i = gzip.GzipFile(iname)
o = gzip.GzipFile(oname, "w")
while True:
magic = i.read(6)
dev = i.read(6)
ino = i.read(6)
mode = i.read(6)
i.read(6) # uid
i.read(6) # gid
nlink = i.read(6)
rdev = i.read(6)
mtime = i.read(11)
namesize = i.read(6)
filesize = i.read(11)
name = i.read(int(namesize, 8))
data = i.read(int(filesize, 8))
o.write(magic)
o.write(dev)
o.write(ino)
o.write(mode)
o.write("000000")
o.write("000000")
o.write(nlink)
o.write(rdev)
o.write(mtime)
o.write(namesize)
o.write(filesize)
o.write(name)
o.write(data)
if name.startswith("TRAILER!!!"):
o.write(i.read())
break
o.close()
i.close()
if __name__ == '__main__':
for iname in sys.argv[1:]:
print('fixing file ownership in %s' % iname)
oname = sys.argv[1] + '.tmp'
fixpax(iname, oname)
os.rename(oname, iname)