Support interface localisation using GNU gettext

The xkeyboard-config library is required as a runtime dependency to
present a localized string of the keyboard layout.

Useful links:
- https://www.gnu.org/software/gettext/manual/gettext.html#Sources
- https://mesonbuild.com/Localisation.html
- https://mesonbuild.com/i18n-module.html

README.md

@@ -34,6 +34,7 @@ Install dependencies:
 * wayland
 * wayland-protocols \*
 * libxkbcommon
+* xkeyboard-config
 * cairo
 * gdk-pixbuf2 \*\*
 * pam (optional)

main.c

@@ -15,6 +15,8 @@
 #include <unistd.h>
 #include <wayland-client.h>
 #include <wordexp.h>
+#include <locale.h>
+#include <libintl.h>
 #include "background-image.h"
 #include "cairo.h"
 #include "comm.h"
@@ -1101,6 +1103,10 @@ int main(int argc, char **argv) {
 	initialize_pw_backend(argc, argv);
 	srand(time(NULL));
 
+	setlocale(LC_ALL, "");
+	bindtextdomain(GETTEXT_PACKAGE, LOCALEDIR);
+	textdomain(GETTEXT_PACKAGE);
+
 	enum line_mode line_mode = LM_LINE;
 	state.failed_attempts = 0;
 	state.args = (struct swaylock_args){

meson.build

@@ -3,7 +3,7 @@ project(
 	'c',
 	version: '1.6',
 	license: 'MIT',
-	meson_version: '>=0.48.0',
+	meson_version: '>=0.50.0',
 	default_options: [
 		'c_std=c11',
 		'warning_level=2',
@@ -27,6 +27,8 @@ sysconfdir = get_option('sysconfdir')
 prefix = get_option('prefix')
 is_freebsd = host_machine.system().startswith('freebsd')
 
+subdir('po')
+
 add_project_arguments(
 	'-DSYSCONFDIR="/@0@"'.format(join_paths(prefix, sysconfdir)),
 	language : 'c')
@@ -38,13 +40,15 @@ endif
 wayland_client = dependency('wayland-client')
 wayland_protos = dependency('wayland-protocols', version: '>=1.14')
 xkbcommon      = dependency('xkbcommon')
+xkeyboard_config = dependency('xkeyboard-config')
 cairo          = dependency('cairo')
 gdk_pixbuf     = dependency('gdk-pixbuf-2.0', required: get_option('gdk-pixbuf'))
 bash_comp      = dependency('bash-completion', required: false)
 fish_comp      = dependency('fish', required: false)
 libpam         = cc.find_library('pam', required: get_option('pam'))
 crypt          = cc.find_library('crypt', required: not libpam.found())
 math           = cc.find_library('m')
+intl           = cc.fing_library('intl', required: false)
 
 git = find_program('git', required: false)
 scdoc = find_program('scdoc', required: get_option('man-pages'))
@@ -116,6 +120,7 @@ dependencies = [
 	cairo,
 	client_protos,
 	gdk_pixbuf,
+	intl,
 	math,
 	xkbcommon,
 	wayland_client,

po/LINGUAS

@@ -0,0 +1 @@
+de fr

po/POTFILES

@@ -0,0 +1 @@
+render.c

po/de.po

@@ -0,0 +1,34 @@
+# German translations for swaylock package.
+# Copyright (C) 2020 THE swaylock'S COPYRIGHT HOLDER
+# This file is distributed under the same license as the swaylock package.
+# Automatically generated, 2020.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: swaylock 1.6\n"
+"Report-Msgid-Bugs-To: https://github.com/swaywm/swaylock/issues\n"
+"POT-Creation-Date: 2020-08-18 14:46+0200\n"
+"PO-Revision-Date: 2020-08-18 15:25+0200\n"
+"Last-Translator: Automatically generated\n"
+"Language-Team: none\n"
+"Language: de\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=(n != 1);\n"
+
+#: render.c:161
+msgid "verifying"
+msgstr "Überprüfung"
+
+#: render.c:164
+msgid "wrong"
+msgstr "falsch"
+
+#: render.c:167
+msgid "cleared"
+msgstr "gelöscht"
+
+#: render.c:174
+msgid "Caps Lock"
+msgstr "Feststelltaste"

po/fr.po

@@ -0,0 +1,34 @@
+# French translations for swaylock package.
+# Copyright (C) 2020 THE swaylock'S COPYRIGHT HOLDER
+# This file is distributed under the same license as the swaylock package.
+# Automatically generated, 2020.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: swaylock 1.6\n"
+"Report-Msgid-Bugs-To: https://github.com/swaywm/swaylock/issues\n"
+"POT-Creation-Date: 2020-08-18 14:46+0200\n"
+"PO-Revision-Date: 2020-08-18 14:50+0200\n"
+"Last-Translator: Automatically generated\n"
+"Language-Team: none\n"
+"Language: fr\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=(n > 1);\n"
+
+#: render.c:161
+msgid "verifying"
+msgstr "vérification"
+
+#: render.c:164
+msgid "wrong"
+msgstr "incorrect"
+
+#: render.c:167
+msgid "cleared"
+msgstr "effacé"
+
+#: render.c:174
+msgid "Caps Lock"
+msgstr "Verr Maj"

po/meson.build

@@ -0,0 +1,17 @@
+i18n = import('i18n')
+
+add_project_arguments(
+	[
+		'-DGETTEXT_PACKAGE="@0@"'.format(meson.project_name()),
+		'-DLOCALEDIR="@0@"'.format(get_option('prefix') / get_option('localedir'))
+	],
+	language:'c'
+)
+i18n.gettext(meson.project_name(),
+	args: [
+		'--directory=' + meson.source_root(),
+		'--package-name=' + meson.project_name(),
+		'--package-version=' + meson.project_version(),
+		'--msgid-bugs-address=https://github.com/swaywm/swaylock/issues',
+	]
+)

po/swaylock.pot

@@ -0,0 +1,34 @@
+# SOME DESCRIPTIVE TITLE.
+# Copyright (C) YEAR THE PACKAGE'S COPYRIGHT HOLDER
+# This file is distributed under the same license as the swaylock package.
+# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
+#
+#, fuzzy
+msgid ""
+msgstr ""
+"Project-Id-Version: swaylock 1.6\n"
+"Report-Msgid-Bugs-To: https://github.com/swaywm/swaylock/issues\n"
+"POT-Creation-Date: 2020-08-18 14:46+0200\n"
+"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
+"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
+"Language-Team: LANGUAGE <[email protected]>\n"
+"Language: \n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=CHARSET\n"
+"Content-Transfer-Encoding: 8bit\n"
+
+#: render.c:161
+msgid "verifying"
+msgstr ""
+
+#: render.c:164
+msgid "wrong"
+msgstr ""
+
+#: render.c:167
+msgid "cleared"
+msgstr ""
+
+#: render.c:174
+msgid "Caps Lock"
+msgstr ""

render.c

@@ -1,6 +1,7 @@
 #include <math.h>
 #include <stdlib.h>
 #include <wayland-client.h>
+#include <libintl.h>
 #include "cairo.h"
 #include "background-image.h"
 #include "swaylock.h"
@@ -157,20 +158,20 @@ void render_frame(struct swaylock_surface *surface) {
 		}
 		switch (state->auth_state) {
 		case AUTH_STATE_VALIDATING:
-			text = "verifying";
+			text = gettext("verifying");
 			break;
 		case AUTH_STATE_INVALID:
-			text = "wrong";
+			text = gettext("wrong");
 			break;
 		case AUTH_STATE_CLEAR:
-			text = "cleared";
+			text = gettext("cleared");
 			break;
 		case AUTH_STATE_INPUT:
 		case AUTH_STATE_INPUT_NOP:
 		case AUTH_STATE_BACKSPACE:
 			// Caps Lock has higher priority
 			if (state->xkb.caps_lock && state->args.show_caps_lock_text) {
-				text = "Caps Lock";
+				text = gettext("Caps Lock");
 			} else if (state->args.show_failed_attempts &&
 					state->failed_attempts > 0) {
 				if (state->failed_attempts > 999) {
@@ -193,7 +194,8 @@ void render_frame(struct swaylock_surface *surface) {
 					++curr_layout;
 				}
 				// will handle invalid index if none are active
-				layout_text = xkb_keymap_layout_get_name(state->xkb.keymap, curr_layout);
+				layout_text = dgettext("xkeyboard-config",
+					xkb_keymap_layout_get_name(state->xkb.keymap, curr_layout));
 			}
 			break;
 		default: