templates: add filter to reverse list
The filter supports only lists because for lists, it’s straightforward to
implement. Reversing text doesn’t seem very useful and is hard to implement.
Reversing the bytes would break multi-bytes encodings. Reversing the code
points would break characters consisting of multiple code points. Reversing
graphemes is non-trivial without using a library not included in the standard
library.
#!/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)