source: config-package-dev/displace.sh.in @ 8dc79e2

#
# displace_link <prefix> <suffix>
#
#   Ensures that the file <prefix><suffix> is properly diverted to
#   <prefix>.divert-orig<suffix> by this package, and becomes a
#   symbolic link to either <prefix>.divert<suffix> (default) or
#   <prefix>.divert-orig<suffix>.
#
# undisplace_unlink <prefix> <suffix>
#
#   Undoes the action of displace_link <prefix> <suffix> specified
#   above.
#
# Version: 4.0
#

package=#PACKAGE#

ours=#DEB_DISPLACE_EXTENSION#
theirs=#DEB_DISPLACE_EXTENSION#-orig

displace_link_displace()
{
    file=$1
    ourfile=$2
    theirfile=$3
    if ! LC_ALL=C dpkg-divert --list "$package" | \
        grep -xFq "diversion of $file to $theirfile by $package"; then
        dpkg-divert --divert "$theirfile" --rename --package "$package" --add "$file"
    fi
}

displace_link_symlink()
{
    file=$1
    ourfile=$2
    theirfile=$3
    if [ ! -L "$file" ] && [ ! -e "$file" ]; then
        ln -s "$(basename "$ourfile")" "$file"
    elif [ ! -L "$file" ] || \
        [ "$(readlink "$file")" != "$(basename "$ourfile")" -a \
          "$(readlink "$file")" != "$(basename "$theirfile")" ]; then
        echo "*** OMINOUS WARNING ***: $file is not linked to either $(basename "$ourfile") or $(basename "$theirfile")" >&2
    fi
}

displace_link()
{
    prefix=$1
    suffix=$2

    file=$prefix$suffix
    ourfile=$prefix$ours$suffix
    theirfile=$prefix$theirs$suffix
    displace_link_displace "$file" "$ourfile" "$theirfile"
    displace_link_symlink "$file" "$ourfile" "$theirfile"
}

displace_hide()
{
    file=$1
    ourfile=""
    theirfile=$2
    displace_link_displace "$file" "$ourfile" "$theirfile"
}

undisplace_unlink_symlink()
{
    file="$1"
    ourfile="$2"
    theirfile="$3"
    if [ ! -L "$file" ] || \
        [ "$(readlink "$file")" != "$(basename "$ourfile")" -a \
          "$(readlink "$file")" != "$(basename "$theirfile")" ]; then
        echo "*** OMINOUS WARNING ***: $file is not linked to either $(basename "$ourfile") or $(basename "$theirfile")" >&2
    else
        rm -f "$file"
    fi
}

undisplace_unlink_displace()
{
    file="$1"
    if [ ! -L "$file" ] && [ ! -e "$file" ]; then
        dpkg-divert --remove --rename --package "$package" "$file"
    else
        echo "Not removing diversion of $file by $package" >&2
    fi
}

undisplace_unlink()
{
    prefix=$1
    suffix=$2

    file=$prefix$suffix
    ourfile=$prefix$ours$suffix
    theirfile=$prefix$theirs$suffix

    undisplace_unlink_symlink "$file" "$ourfile" "$theirfile"
    undisplace_unlink_displace "$file"
}

undisplace_unhide()
{
    file=$1
    undisplace_unlink_displace "$file"
}

check_undisplace_unlink()
{
    prefix=$1
    suffix=$2

    file=$prefix$suffix
    ourfile=$prefix$ours$suffix
    theirfile=$prefix$theirs$suffix

    if LC_ALL=C dpkg-divert --list "$package" | \
        grep -xFq "diversion of $file to $theirfile by $package"; then
        undisplace_unlink "$prefix" "$suffix"
    fi
}

check_undisplace_unhide()
{
    file=$1
    hiddenfile=$2
    if LC_ALL=C dpkg-divert --list "$package" | \
        grep -xFq "diversion of $file to $hiddenfile by $package"; then
        undisplace_unhide "$file"
    fi
}