#!/bin/sh

USAGE='[--mixed | --soft | --hard]  [<commit-ish>]'
. git-sh-setup

tmp=${GIT_DIR}/reset.$$
trap 'rm -f $tmp-*' 0 1 2 3 15

update=
reset_type=--mixed
case "$1" in
--mixed | --soft | --hard)
        reset_type="$1"
        shift
        ;;
-*)
        usage ;;
esac

rev=$(git-rev-parse --verify --default HEAD "$@") || exit
rev=$(git-rev-parse --verify $rev^0) || exit

# We need to remember the set of paths that _could_ be left
# behind before a hard reset, so that we can remove them.
if test "$reset_type" = "--hard"
then
        update=-u
fi

# Soft reset does not touch the index file nor the working tree
# at all, but requires them in a good order.  Other resets reset
# the index file to the tree object we are switching to.
if test "$reset_type" = "--soft"
then
        if test -f "$GIT_DIR/MERGE_HEAD" ||
           test "" != "$(git-ls-files --unmerged)"
        then
                die "Cannot do a soft reset in the middle of a merge."
        fi
else
        git-read-tree --reset $update "$rev" || exit
fi

# Any resets update HEAD to the head being switched to.
if orig=$(git-rev-parse --verify HEAD 2>/dev/null)
then
        echo "$orig" >"$GIT_DIR/ORIG_HEAD"
else
        rm -f "$GIT_DIR/ORIG_HEAD"
fi
git-update-ref HEAD "$rev"

case "$reset_type" in
--hard )
        ;; # Nothing else to do
--soft )
        ;; # Nothing else to do
--mixed )
        # Report what has not been updated.
        git-update-index --refresh
        ;;
esac

rm -f "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/rr-cache/MERGE_RR"