branchcache: skip entries that are topological heads in the on disk file
In the majority of cases, topological heads are also branch heads. We have
efficient way to get the topological heads and efficient way to retrieve
their branch information. So there is little value in putting them in the branch
cache file explicitly. On the contrary, writing them explicitly tend to create
very large cache file that are inefficient to read and update.
So the branch cache v3 format is no longer including them. This changeset focus
on the format aspect and have no focus on the performance aspect. We will cover
that later.
#!/usr/bin/env python3
#
# simple script to be used in hooks
#
# put something like this in the repo .hg/hgrc:
#
# [hooks]
# changegroup = python "$TESTDIR/printenv.py" <hookname> [exit] [output]
#
# - <hookname> is a mandatory argument (e.g. "changegroup")
# - [exit] is the exit code of the hook (default: 0)
# - [output] is the name of the output file (default: use sys.stdout)
# the file will be opened in append mode.
#
import argparse
import os
import sys
try:
import msvcrt
msvcrt.setmode(sys.stdin.fileno(), os.O_BINARY)
msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
msvcrt.setmode(sys.stderr.fileno(), os.O_BINARY)
except ImportError:
pass
parser = argparse.ArgumentParser()
parser.add_argument("name", help="the hook name, used for display")
parser.add_argument(
"exitcode",
nargs="?",
default=0,
type=int,
help="the exit code for the hook",
)
parser.add_argument(
"out", nargs="?", default=None, help="where to write the output"
)
parser.add_argument(
"--line",
action="store_true",
help="print environment variables one per line instead of on a single line",
)
args = parser.parse_args()
if args.out is None:
out = sys.stdout
out = getattr(out, "buffer", out)
else:
out = open(args.out, "ab")
# variables with empty values may not exist on all platforms, filter
# them now for portability sake.
env = [(k, v) for k, v in os.environ.items() if k.startswith("HG_") and v]
env.sort()
out.write(b"%s hook: " % args.name.encode('ascii'))
if os.name == 'nt':
filter = lambda x: x.replace('\\', '/')
else:
filter = lambda x: x
vars = [
b"%s=%s" % (k.encode('ascii'), filter(v).encode('ascii')) for k, v in env
]
# Print variables on out
if not args.line:
out.write(b" ".join(vars))
else:
for var in vars:
out.write(var)
out.write(b"\n")
out.write(b"\n")
out.close()
sys.exit(args.exitcode)