#!/usr/bin/env python
"""Test the running system for features availability. Exit with zero
if all features are there, non-zero otherwise. If a feature name is
prefixed with "no-", the absence of feature is tested.
"""
import optparse
import os
import sys
import tempfile

tempprefix = 'hg-hghave-'

def has_symlink():
    return hasattr(os, "symlink")

def has_fifo():
    return hasattr(os, "mkfifo")

def has_executablebit():
    fd, path = tempfile.mkstemp(prefix=tempprefix)
    os.close(fd)
    try:
        s = os.lstat(path).st_mode
        os.chmod(path, s | 0100)
        return (os.lstat(path).st_mode & 0100 != 0)
    finally:
        os.remove(path)

def has_eol_in_paths():
    try:
        fd, path = tempfile.mkstemp(prefix=tempprefix, suffix='\n\r')
        os.close(fd)
        os.remove(path)
        return True
    except:
        return False

checks = {
    "symlink": (has_symlink, "symbolic links"),
    "fifo": (has_fifo, "named pipes"),
    "execbit": (has_executablebit, "executable bit"),
    "eol-in-paths": (has_eol_in_paths, "end-of-lines in paths"),
}

def list_features():
    for name, feature in checks.iteritems():
        desc = feature[1]
        print name + ':', desc

parser = optparse.OptionParser("%prog [options] [features]")
parser.add_option("--list-features", action="store_true",
                  help="list available features")
parser.add_option("-q", "--quiet", action="store_true",
                  help="check features silently")

if __name__ == '__main__':
    options, args = parser.parse_args()
    if options.list_features:
        list_features()
        sys.exit(0)

    quiet = options.quiet

    failures = 0

    def error(msg):
        global failures
        if not quiet:
            sys.stderr.write(msg + '\n')
        failures += 1

    for feature in args:
        negate = feature.startswith('no-')
        if negate:
            feature = feature[3:]

        if feature not in checks:
            error('hghave: unknown feature: ' + feature)
            continue

        check, desc = checks[feature]
        if not negate and not check():
            error('hghave: missing feature: ' + desc)
        elif negate and check():
            error('hghave: unexpected feature: ' + desc)

    if failures != 0:
        sys.exit(1)