phases: use revision number in new_heads
All graph operations will be done using revision numbers, so passing nodes only
means they will eventually get converted to revision numbers internally.
As part of an effort to align the code on using revision number we make the
`phases.newheads` function operated on revision number, taking them as input
and using them in returns, instead of the node-id it used to consume and
produce.
This is part of multiple changesets effort to translate more part of the logic,
but is done step by step to facilitate the identification of issue that might
arise in mercurial core and extensions.
To make the change simpler to handle for third party extensions, we also rename
the function, using a more modern form. This will help detecting the different
between the node-id version and the rev-num version.
I also take this as an opportunity to add some comment about possible
performance improvement for the future. They don't matter too much now, but they
are worse exploring in a while.
#!/usr/bin/env python3
#
# Copyright 2018 Google LLC.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""Tool read primitive events from a pipe to produce a catapult trace.
Usage:
Terminal 1: $ catapipe.py /tmp/mypipe /tmp/trace.json
Terminal 2: $ HGCATAPULTSERVERPIPE=/tmp/mypipe hg root
<ctrl-c catapipe.py in Terminal 1>
$ catapult/tracing/bin/trace2html /tmp/trace.json # produce /tmp/trace.html
<open trace.html in your browser of choice; the WASD keys are very useful>
(catapult is located at https://github.com/catapult-project/catapult)
For now the event stream supports
START $SESSIONID ...
and
END $SESSIONID ...
events. Everything after the SESSIONID (which must not contain spaces)
is used as a label for the event. Events are timestamped as of when
they arrive in this process and are then used to produce catapult
traces that can be loaded in Chrome's about:tracing utility. It's
important that the event stream *into* this process stay simple,
because we have to emit it from the shell scripts produced by
run-tests.py.
Typically you'll want to place the path to the named pipe in the
HGCATAPULTSERVERPIPE environment variable, which both run-tests and hg
understand. To trace *only* run-tests, use HGTESTCATAPULTSERVERPIPE instead.
"""
import argparse
import json
import os
import timeit
_TYPEMAP = {
'START': 'B',
'END': 'E',
'COUNTER': 'C',
}
_threadmap = {}
# Timeit already contains the whole logic about which timer to use based on
# Python version and OS
timer = timeit.default_timer
def main():
parser = argparse.ArgumentParser()
parser.add_argument(
'pipe',
type=str,
nargs=1,
help='Path of named pipe to create and listen on.',
)
parser.add_argument(
'output',
default='trace.json',
type=str,
nargs='?',
help='Path of json file to create where the traces ' 'will be stored.',
)
parser.add_argument(
'--debug',
default=False,
action='store_true',
help='Print useful debug messages',
)
args = parser.parse_args()
fn = args.pipe[0]
os.mkfifo(fn)
try:
with open(fn) as f, open(args.output, 'w') as out:
out.write('[\n')
start = timer()
while True:
ev = f.readline().strip()
if not ev:
continue
now = timer()
if args.debug:
print(ev)
verb, session, label = ev.split(' ', 2)
if session not in _threadmap:
_threadmap[session] = len(_threadmap)
if verb == 'COUNTER':
amount, label = label.split(' ', 1)
payload_args = {'value': int(amount)}
else:
payload_args = {}
pid = _threadmap[session]
ts_micros = (now - start) * 1000000
out.write(
json.dumps(
{
"name": label,
"cat": "misc",
"ph": _TYPEMAP[verb],
"ts": ts_micros,
"pid": pid,
"tid": 1,
"args": payload_args,
}
)
)
out.write(',\n')
finally:
os.unlink(fn)
if __name__ == '__main__':
main()