procutil: make stream detection in make_line_buffered more correct and strict
In make_line_buffered(), we don’t want to wrap the stream if we know that lines
get flushed to the underlying raw stream already.
Previously, the heuristic was too optimistic. It assumed that any stream which
is not an instance of io.BufferedIOBase doesn’t need wrapping. However, there
are buffered streams that aren’t instances of io.BufferedIOBase, like
Mercurial’s own winstdout.
The new logic is different in two ways:
First, only for the check, if unwraps any combination of WriteAllWrapper and
winstdout.
Second, it skips wrapping the stream only if it is an instance of io.RawIOBase
(or already wrapped). If it is an instance of io.BufferedIOBase, it gets
wrapped. In any other case, the function raises an exception. This ensures
that, if an unknown stream is passed or we add another wrapper in the future,
we don’t wrap the stream if it’s already line buffered or not wrap the stream
if it’s not line buffered. In fact, this was already helpful during development
of this change. Without it, I possibly would have forgot that WriteAllWrapper
needs to be ignored for the check, leading to unnecessary wrapping if stdout is
unbuffered.
The alternative would have been to always wrap unknown streams. However, I
don’t think that anyone would benefit from being less strict. We can expect
streams from the standard library to be subclassing either io.RawIOBase or
io.BufferedIOBase, so running Mercurial in the standard way should not regress
by this change. Py2exe might replace sys.stdout and sys.stderr, but that
currently breaks Mercurial anyway and also these streams don’t claim to be
interactive, so this function is not called for them.
#!/usr/bin/env python3
#
# hgperf - measure performance of Mercurial commands
#
# Copyright 2014 Olivia Mackall <olivia@selenic.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
'''measure performance of Mercurial commands
Using ``hgperf`` instead of ``hg`` measures performance of the target
Mercurial command. For example, the execution below measures
performance of :hg:`heads --topo`::
$ hgperf heads --topo
All command output via ``ui`` is suppressed, and just measurement
result is displayed: see also "perf" extension in "contrib".
Costs of processing before dispatching to the command function like
below are not measured::
- parsing command line (e.g. option validity check)
- reading configuration files in
But ``pre-`` and ``post-`` hook invocation for the target command is
measured, even though these are invoked before or after dispatching to
the command function, because these may be required to repeat
execution of the target command correctly.
'''
import os
import sys
libdir = '@LIBDIR@'
if libdir != '@' 'LIBDIR' '@':
if not os.path.isabs(libdir):
libdir = os.path.join(
os.path.dirname(os.path.realpath(__file__)), libdir
)
libdir = os.path.abspath(libdir)
sys.path.insert(0, libdir)
# enable importing on demand to reduce startup time
try:
from mercurial import demandimport
demandimport.enable()
except ImportError:
import sys
sys.stderr.write(
"abort: couldn't find mercurial libraries in [%s]\n"
% ' '.join(sys.path)
)
sys.stderr.write("(check your install and PYTHONPATH)\n")
sys.exit(-1)
from mercurial import (
dispatch,
util,
)
def timer(func, title=None):
results = []
begin = util.timer()
count = 0
while True:
ostart = os.times()
cstart = util.timer()
r = func()
cstop = util.timer()
ostop = os.times()
count += 1
a, b = ostart, ostop
results.append((cstop - cstart, b[0] - a[0], b[1] - a[1]))
if cstop - begin > 3 and count >= 100:
break
if cstop - begin > 10 and count >= 3:
break
if title:
sys.stderr.write("! %s\n" % title)
if r:
sys.stderr.write("! result: %s\n" % r)
m = min(results)
sys.stderr.write(
"! wall %f comb %f user %f sys %f (best of %d)\n"
% (m[0], m[1] + m[2], m[1], m[2], count)
)
orgruncommand = dispatch.runcommand
def runcommand(lui, repo, cmd, fullargs, ui, options, d, cmdpats, cmdoptions):
ui.pushbuffer()
lui.pushbuffer()
timer(
lambda: orgruncommand(
lui, repo, cmd, fullargs, ui, options, d, cmdpats, cmdoptions
)
)
ui.popbuffer()
lui.popbuffer()
dispatch.runcommand = runcommand
dispatch.run()