hgeditor

dirstate: make writing in-memory changes aware of transaction activity

This patch delays writing in-memory changes out, if transaction is
running.

'_getfsnow()' is defined as a function, to hook it easily for
ambiguous timestamp tests (see also fakedirstatewritetime.py)

'if tr:' code path in this patch is still disabled at this revision,
because there is no client invoking 'dirstate.write()' with repo
object.

BTW, this patch changes 'dirstate.invalidate()' semantics around
'dirstate.write()' in a transaction scope:

  before:
    with repo.transaction():
        dirstate.CHANGE('A')
        dirstate.write() # change for A is written out here
        dirstate.CHANGE('B')
        dirstate.invalidate() # discards only change for B

  after:
    with repo.transaction():
        dirstate.CHANGE('A')
        dirstate.write() # change for A is still kept in memory
        dirstate.CHANGE('B')
        dirstate.invalidate() # discards changes for A and B

Fortunately, there is no code path expecting the former, at least, in
Mercurial itself, because 'dirstateguard' was introduced to remove
such 'dirstate.invalidate()'.

#!/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 $?