Docs: Add support for bash-completion

CHANGES

@@ -6,10 +6,11 @@ website will have to do for older versions.
 # 3.2.24 (unreleased) #
 
 This release contains contributions from (alphabetically by first name):
- - No external contributors yet
+ - Gaël PORTAY
 
 ## Core ##
- - No core changes yet
+ - There is now a bash-completions script for Calamares; turn on
+   the (CMake-time) option INSTALL_COMPLETION to get it. (Thanks Gaël)
 
 ## Modules ##
  - No module changes yet

CMakeLists.txt

@@ -49,6 +49,7 @@ set( CALAMARES_VERSION_RC 1 )  # Set to 0 during release cycle, 1 during develop
 #
 option( INSTALL_CONFIG "Install configuration files" OFF )
 option( INSTALL_POLKIT "Install Polkit configuration" ON )
+option( INSTALL_COMPLETION "Install shell completions" OFF )
 option( BUILD_TESTING "Build the testing tree." ON )
 option( WITH_PYTHON "Enable Python modules API (requires Boost.Python)." ON )
 option( WITH_PYTHONQT "Enable next generation Python modules API (experimental, requires PythonQt)." OFF )
@@ -389,6 +390,13 @@ list( SORT CALAMARES_TRANSLATION_LANGUAGES )
 
 add_subdirectory( lang )  # i18n tools
 
+if ( INSTALL_COMPLETION )
+    if( NOT CMAKE_INSTALL_BASHCOMPLETIONDIR )
+        set( CMAKE_INSTALL_BASHCOMPLETIONDIR "${CMAKE_INSTALL_DATADIR}/bash-completion/completions" )
+    endif()
+
+    install( FILES ${CMAKE_SOURCE_DIR}/data/completion/bash/calamares DESTINATION "${CMAKE_INSTALL_BASHCOMPLETIONDIR}" )
+endif()
 
 ### Example Distro
 #

data/completion/bash/calamares

@@ -0,0 +1,36 @@
+# === This file is part of Calamares - <https://github.com/calamares> ===
+#
+#   Copyright 2020, Gaël PORTAY <gael.portay@gmail.com>
+#
+#   Calamares is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   Calamares 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 General Public License
+#   along with Calamares. If not, see <http://www.gnu.org/licenses/>.
+
+_calamares()
+{
+    local cur prev words cword
+    _init_completion || return
+
+    case "$prev" in
+        -D)
+            COMPREPLY=( $( compgen -W "$( seq 0 1 8 )" -- "$cur" ) )
+            return
+            ;;
+        -c|--config)
+            _filedir
+            return
+            ;;
+    esac
+
+    COMPREPLY=( $( compgen -W "-h --help -v --version -d --debug -D -c --config -X -xdg-config -T --debug-translation" -- "$cur" ) )
+} &&
+complete -F _calamares calamares