window-title: implement window-title command line argument

When -t or --window-title is supplied, its required argument is treated as a
format string where `%o` is replaced by the `wlr-output`'s `name` when we set
the window title.

This uses glib to split and join the format string because our own
`string-helpers` library only has `str_join`. Otherwise using `string-helpers`
would have been preferred.

include/labwc.h

@@ -315,6 +315,8 @@ struct server {
 	struct sfdo *sfdo;
 
 	pid_t primary_client_pid;
+
+	char *window_title_fmt;
 };
 
 /* defined in main.c */

src/main.c

@@ -9,6 +9,7 @@
 #include "common/font.h"
 #include "common/macros.h"
 #include "common/spawn.h"
+#include "common/string-helpers.h"
 #include "config/rcxml.h"
 #include "config/session.h"
 #include "labwc.h"
@@ -37,6 +38,7 @@ static const struct option long_options[] = {
 	{"reconfigure", no_argument, NULL, 'r'},
 	{"startup", required_argument, NULL, 's'},
 	{"session", required_argument, NULL, 'S'},
+	{"window-title", required_argument, NULL, 't'},
 	{"version", no_argument, NULL, 'v'},
 	{"verbose", no_argument, NULL, 'V'},
 	{0, 0, 0, 0}
@@ -178,7 +180,7 @@ main(int argc, char *argv[])
 	int c;
 	while (1) {
 		int index = 0;
-		c = getopt_long(argc, argv, "c:C:dehmrs:S:vV", long_options, &index);
+		c = getopt_long(argc, argv, "c:C:dehmrs:S:t:vV", long_options, &index);
 		if (c == -1) {
 			break;
 		}
@@ -207,6 +209,9 @@ main(int argc, char *argv[])
 		case 'S':
 			primary_client = optarg;
 			break;
+		case 't':
+			server.window_title_fmt = optarg;
+			break;
 		case 'v':
 			print_version();
 			exit(0);
@@ -265,6 +270,10 @@ main(int argc, char *argv[])
 
 	increase_nofile_limit();
 
+	if (string_null_or_empty(server.window_title_fmt)) {
+		server.window_title_fmt = "labwc - %o";
+	}
+
 	server_init();
 	server_start();
 

src/output.c

@@ -10,6 +10,7 @@
 #include "output.h"
 #include <assert.h>
 #include <drm_fourcc.h>
+#include <glib.h>
 #include <strings.h>
 #include <wlr/backend/wayland.h>
 #include <wlr/config.h>
@@ -26,6 +27,7 @@
 #include "common/macros.h"
 #include "common/mem.h"
 #include "common/scene-helpers.h"
+#include "common/string-helpers.h"
 #include "config/rcxml.h"
 #include "labwc.h"
 #include "layers.h"
@@ -605,13 +607,11 @@ handle_new_output(struct wl_listener *listener, void *data)
 	}
 
 	if (wlr_output_is_wl(wlr_output)) {
-		char title[64];
+		gchar** parts = g_strsplit(server.window_title_fmt, "%o", -1);
-		if (getenv("LABWC_TITLE")) {
+		gchar* formatted_title = g_strjoinv(wlr_output->name, parts);
-			snprintf(title, sizeof(title), "%s", getenv("LABWC_TITLE"));
+		g_strfreev(parts);
-		} else {
+		wlr_wl_output_set_title(wlr_output, formatted_title);
-			snprintf(title, sizeof(title), "%s - %s", "labwc", wlr_output->name);
+		g_free(formatted_title);
-		}
-		wlr_wl_output_set_title(wlr_output, title);
 		wlr_wl_output_set_app_id(wlr_output, "labwc");
 	}