hgeditor

style: kill ersatz if-else ternary operators

Although Python supports `X = Y if COND else Z`, this was only
introduced in Python 2.5. Since we have to support Python 2.4, it was
a very common thing to write instead `X = COND and Y or Z`, which is a
bit obscure at a glance. It requires some intricate knowledge of
Python to understand how to parse these one-liners.

We change instead all of these one-liners to 4-liners. This was
executed with the following perlism:

    find -name "*.py" -exec perl -pi -e 's,(\s*)([\.\w]+) = \(?(\S+)\s+and\s+(\S*)\)?\s+or\s+(\S*)$,$1if $3:\n$1    $2 = $4\n$1else:\n$1    $2 = $5,' {} \;

I tweaked the following cases from the automatic Perl output:

    prev = (parents and parents[0]) or nullid
    port = (use_ssl and 443 or 80)
    cwd = (pats and repo.getcwd()) or ''
    rename = fctx and webutil.renamelink(fctx) or []
    ctx = fctx and fctx or ctx
    self.base = (mapfile and os.path.dirname(mapfile)) or ''

I also added some newlines wherever they seemd appropriate for readability

There are probably a few ersatz ternary operators still in the code
somewhere, lurking away from the power of a simple regex.

#!/bin/sh
#
# This is an example of using HGEDITOR to create of diff to review the
# changes while commiting.

# If you want to pass your favourite editor some other parameters
# only for Mercurial, modify this:
case "${EDITOR}" in
    "")
        EDITOR="vi"
        ;;
    emacs)
        EDITOR="$EDITOR -nw"
        ;;
    gvim|vim)
        EDITOR="$EDITOR -f -o"
        ;;
esac


HGTMP=""
cleanup_exit() {
    rm -rf "$HGTMP"
}

# Remove temporary files even if we get interrupted
trap "cleanup_exit" 0 # normal exit
trap "exit 255" HUP INT QUIT ABRT TERM

HGTMP=$(mktemp -d ${TMPDIR-/tmp}/hgeditor.XXXXXX)
[ x$HGTMP != x -a -d $HGTMP ] || {
  echo "Could not create temporary directory! Exiting." 1>&2
  exit 1
}

(
    grep '^HG: changed' "$1" | cut -b 13- | while read changed; do
        "$HG" diff "$changed" >> "$HGTMP/diff"
    done
)

cat "$1" > "$HGTMP/msg"

MD5=$(which md5sum 2>/dev/null) || \
    MD5=$(which md5 2>/dev/null)
[ -x "${MD5}" ] && CHECKSUM=`${MD5} "$HGTMP/msg"`
if [ -s "$HGTMP/diff" ]; then
    $EDITOR "$HGTMP/msg" "$HGTMP/diff" || exit $?
else
    $EDITOR "$HGTMP/msg" || exit $?
fi
[ -x "${MD5}" ] && (echo "$CHECKSUM" | ${MD5} -c >/dev/null 2>&1 && exit 13)

mv "$HGTMP/msg" "$1"

exit $?