hgeditor

mq: add --currentdate and --date options to qnew and qrefresh

These options make qnew add and qrefresh update a "# Date "-style
header line. This allows proper recording of creation / last
modification dates of patches in patch queues.

Note that `qrefresh -D` only updates existing header lines. It never
adds them, and does not warn about this. This is because I expect
people to have `[default] qrefresh -D` in their .hgrc so patches with
tracked dates get updated, others are left unchanged. The suggested
setup in .hgrc is, in fact,

  [default]
  qnew = -D -U
  qrefresh = -D

I tried to not mix header styles, so `qnew -D -U` now writes the user in
"# User "-style, while `qnew -U` still writes it "From: "-style. Also, if
`qrefresh -U` must add the user, it does so in "# User "-style if the
header contains a "# HG changeset patch" line. (This is caused by mq
not supporting the "Date: "-style header line at all - a reasonable choice
given its standard date format.)

#!/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" 1 2 3 6 15 # HUP INT QUIT ABRT TERM

HGTMP="${TMPDIR-/tmp}/hgeditor.$RANDOM.$RANDOM.$RANDOM.$$"
(umask 077 && mkdir "$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 $?