hgeditor

hidden: simplify the computation of consistency blocker

For a couple of years, we now have precomputed set for all mutable phases. We
can use this set restrict our search and quickly detect non-hideable children of
hideable changesets.  This speeds up the hidden computation. See docstring of
the new function for details.

This new version reuses the '_domainancestors' function to keep the computation
of revealed changeset in O(len(visible))

Below are perfvolatilesets timing from two Mozilla repositories with different
contents. hidden cache is disabled while obtaining them.

1) Mozilla repository with:
 * 400667 changesets
 * 35 hidden changesets (first rev-268334)
 * 288 visible drafts
 * 1 unstable changeset

Before:
! visible
! wall 0.001744 comb 0.000000 user 0.000000 sys 0.000000 (best of 1563)

After:
! visible
! wall 0.000742 comb 0.000000 user 0.000000 sys 0.000000 (best of 3755)


The timing above include the computation of obsolete changeset:
! obsolete
! wall 0.000396 comb 0.000000 user 0.000000 sys 0.000000 (best of 6816)

So adjusted time give 1.3ms before versus 0.3ms after. A 4x speedup.

2) Mozilla repository with:
 * 405645 changesets
 * 4312 hidden changesets (first rev-326004)
 * 264 visible drafts
 * 1 unstable changeset

Before:
! visible
! wall 0.025476 comb 0.030000 user 0.030000 sys 0.000000 (best of 111)


After
! visible
! wall 0.007703 comb 0.010000 user 0.010000 sys 0.000000 (best of 358)


The timing above include the computation of obsolete changeset:
! obsolete
! wall 0.006408 comb 0.010000 user 0.010000 sys 0.000000 (best of 404)

So adjusted time give 19ms before versus 1.3ms after. A 17x speedup.

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

# 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 $?