delta: add bash completion

Makefile.am

@@ -351,6 +351,7 @@ dist_bashcompletion_DATA = \
 	shell-completion/bash/journalctl \
 	shell-completion/bash/systemctl \
 	shell-completion/bash/systemd-analyze \
+	shell-completion/bash/systemd-delta \
 	shell-completion/bash/systemd-run \
 	shell-completion/bash/udevadm \
 	shell-completion/bash/kernel-install

shell-completion/bash/systemd-delta

@@ -0,0 +1,61 @@
+# systemd-delta(1) completion                      -*- shell-script -*-
+#
+# This file is part of systemd.
+#
+# Copyright 2014 Thomas H.P. Andersen
+#
+# systemd is free software; you can redistribute it and/or modify it
+# under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation; either version 2.1 of the License, or
+# (at your option) any later version.
+#
+# systemd is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with systemd; If not, see <http://www.gnu.org/licenses/>.
+
+__contains_word() {
+        local w word=$1; shift
+        for w in "$@"; do
+                [[ $w = "$word" ]] && return
+        done
+}
+
+_systemd-delta() {
+        local cur=${COMP_WORDS[COMP_CWORD]} prev=${COMP_WORDS[COMP_CWORD-1]}
+        local comps
+
+        local -A OPTS=(
+               [STANDALONE]='--help -h --no-pager --version'
+                      [ARG]='--diff --type -t'
+        )
+
+        _init_completion || return
+
+
+        if __contains_word "$prev" ${OPTS[ARG]}; then
+                case $prev in
+                        --diff)
+                                comps='yes no'
+                        ;;
+                        --type|-t)
+                                comps='masked equivalent redirected overridden unchanged extended default'
+                        ;;
+                esac
+                COMPREPLY=( $(compgen -W '$comps' -- "$cur") )
+                return 0
+        fi
+
+        if [[ "$cur" = -* ]]; then
+                COMPREPLY=( $(compgen -W '${OPTS[*]}' -- "$cur") )
+                return 0
+        fi
+
+        COMPREPLY=( $(compgen -W '$comps' -- "$cur") )
+        return 0
+}
+
+complete -F _systemd-delta systemd-delta