src/main: delay startup of applications until event loop is ready

This mostly allows for using scripts that trigger a labwc SIGHUP
to work as expected. Before this patch, there was a race between
the event loop starting up and the autostart scripts executing.

One example of such a use-case is dynamically setting the keyboard
layout or cursor theme via environment variable based on feedback
from a dbus service like discussed in #1588.

diff --git a/src/main.c b/src/main.c
index 1fdfcd3add55162b292f06ee3e584ae74e93b2c6..539d318c147adb9d397a0b3e1751bbd2bc8d2b40 100644 (file)
--- a/src/main.c
+++ b/src/main.c
@@ -80,6 +80,35 @@ send_signal_to_labwc_pid(int signal)
        kill(pid, signal);
 }
 
+struct idle_ctx {
+       struct server *server;
+       const char *primary_client;
+       const char *startup_cmd;
+};
+
+static void
+idle_callback(void *data)
+{
+       /* Idle callbacks destroy automatically once triggerd */
+       struct idle_ctx *ctx = data;
+
+       /* Start session-manager if one is specified by -S|--session */
+       if (ctx->primary_client) {
+               ctx->server->primary_client_pid = spawn_primary_client(ctx->primary_client);
+               if (ctx->server->primary_client_pid < 0) {
+                       wlr_log(WLR_ERROR, "fatal error starting primary client: %s",
+                               ctx->primary_client);
+                       wl_display_terminate(ctx->server->wl_display);
+                       return;
+               }
+       }
+
+       session_autostart_init(ctx->server);
+       if (ctx->startup_cmd) {
+               spawn_async_no_shell(ctx->startup_cmd);
+       }
+}
+
 int
 main(int argc, char *argv[])
 {
@@ -177,24 +206,16 @@ main(int argc, char *argv[])
 
        menu_init(&server);
 
-       /* Start session-manager if one is specified by -S|--session */
-       if (primary_client) {
-               server.primary_client_pid = spawn_primary_client(primary_client);
-               if (server.primary_client_pid < 0) {
-                       wlr_log(WLR_ERROR, "fatal error starting primary client: %s",
-                               primary_client);
-                       goto out;
-               }
-       }
-
-       session_autostart_init(&server);
-       if (startup_cmd) {
-               spawn_async_no_shell(startup_cmd);
-       }
+       /* Delay startup of applications until the event loop is ready */
+       struct idle_ctx idle_ctx = {
+               .server = &server,
+               .primary_client = primary_client,
+               .startup_cmd = startup_cmd
+       };
+       wl_event_loop_add_idle(server.wl_event_loop, idle_callback, &idle_ctx);
 
        wl_display_run(server.wl_display);
 
-out:
        session_shutdown(&server);
 
        server_finish(&server);