tests/printenv.py

rust: iterator bindings to C code

In this changeset, still made of Rust code only,
we expose the Rust iterator for instantiation and
consumption from C code.

The idea is that both the index and index_get_parents()
will be passed from the C extension, hence avoiding a hard
link dependency to parsers.so, so that the crate can
still be built and tested independently.

On the other hand, parsers.so will use the symbols
defined in this changeset.

#!/usr/bin/env python
#
# 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.
#
from __future__ import absolute_import
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

exitcode = 0
out = sys.stdout
out = getattr(out, 'buffer', out)

name = sys.argv[1]
if len(sys.argv) > 2:
    exitcode = int(sys.argv[2])
    if len(sys.argv) > 3:
        out = open(sys.argv[3], "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: " % 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]
out.write(b" ".join(vars))
out.write(b"\n")
out.close()

sys.exit(exitcode)