Netplay netpacket connection flow improvements (#15986)

- Allow starting netplay host while a netpacket core is running without restart
- Allow connecting to a host while a netpacket core is running without restart
- Avoid clients getting stuck in connection loop if the host has the content paused while a client connects by automatically unpausing

menu/cbs/menu_cbs_ok.c

@@ -7701,7 +7701,14 @@ static void action_ok_netplay_enable_client_hostname_cb(void *userdata,
 {
    if (!string_is_empty(line))
    {
-      if (!task_push_netplay_content_reload(line))
+      if (netplay_driver_ctl(RARCH_NETPLAY_CTL_USE_CORE_PACKET_INTERFACE, NULL))
+      {
+         netplay_driver_ctl(RARCH_NETPLAY_CTL_ENABLE_CLIENT, NULL);
+         command_event(CMD_EVENT_NETPLAY_INIT_DIRECT, (void*)line);
+         menu_input_dialog_end();
+         retroarch_menu_running_finished(false);
+      }
+      else if (!task_push_netplay_content_reload(line))
       {
 #ifdef HAVE_DYNAMIC
          command_event(CMD_EVENT_NETPLAY_DEINIT, NULL);

network/netplay/netplay_defines.h

@@ -76,7 +76,7 @@ enum rarch_netplay_ctl_state
    RARCH_NETPLAY_CTL_KICK_CLIENT,
    RARCH_NETPLAY_CTL_BAN_CLIENT,
    RARCH_NETPLAY_CTL_SET_CORE_PACKET_INTERFACE,
-   RARCH_NETPLAY_CTL_SKIP_NETPLAY_CALLBACKS,
+   RARCH_NETPLAY_CTL_USE_CORE_PACKET_INTERFACE,
    RARCH_NETPLAY_CTL_ALLOW_TIMESKIP
 };
 

network/netplay/netplay_frontend.c

@@ -9242,9 +9242,17 @@ bool netplay_driver_ctl(enum rarch_netplay_ctl_state state, void *data)
          break;
 
       case RARCH_NETPLAY_CTL_PAUSE:
-         if (       netplay
-               && (!(netplay->local_paused)))
+         if (netplay && !netplay->local_paused)
             netplay_frontend_paused(netplay, true);
+
+         if (netplay && netplay->modus == NETPLAY_MODUS_CORE_PACKET_INTERFACE)
+         {
+            /* handle new connections while paused, unpause on connect */
+            if (!netplay_sync_pre_frame(netplay))
+               netplay_disconnect(netplay);
+            else if (netplay_have_any_active_connection(netplay))
+               command_event(CMD_EVENT_UNPAUSE, NULL);
+         }
          break;
 
       case RARCH_NETPLAY_CTL_UNPAUSE:
@@ -9372,7 +9380,7 @@ bool netplay_driver_ctl(enum rarch_netplay_ctl_state state, void *data)
          }
          break;
 
-      case RARCH_NETPLAY_CTL_SKIP_NETPLAY_CALLBACKS:
+      case RARCH_NETPLAY_CTL_USE_CORE_PACKET_INTERFACE:
          ret = (net_st->core_netpacket_interface != NULL);
          break;
 

retroarch.c

@@ -3958,7 +3958,12 @@ bool command_event(enum event_command cmd, void *data)
          break;
       case CMD_EVENT_NETPLAY_ENABLE_HOST:
          {
-            if (!task_push_netplay_content_reload(NULL))
+            if (netplay_driver_ctl(RARCH_NETPLAY_CTL_USE_CORE_PACKET_INTERFACE, NULL))
+            {
+               netplay_driver_ctl(RARCH_NETPLAY_CTL_ENABLE_SERVER, NULL);
+               command_event(CMD_EVENT_NETPLAY_INIT, NULL);
+            }
+            else if (!task_push_netplay_content_reload(NULL))
             {
 #ifdef HAVE_DYNAMIC
                command_event(CMD_EVENT_NETPLAY_DEINIT, NULL);

runloop.c

@@ -7445,7 +7445,7 @@ bool core_set_netplay_callbacks(void)
 {
    runloop_state_t *runloop_st        = &runloop_state;
 
-   if (netplay_driver_ctl(RARCH_NETPLAY_CTL_SKIP_NETPLAY_CALLBACKS, NULL))
+   if (netplay_driver_ctl(RARCH_NETPLAY_CTL_USE_CORE_PACKET_INTERFACE, NULL))
       return true;
 
    /* Force normal poll type for netplay. */
@@ -8031,7 +8031,7 @@ void runloop_path_set_redirect(settings_t *settings,
    /* Special save directory for netplay clients. */
    if (      netplay_driver_ctl(RARCH_NETPLAY_CTL_IS_ENABLED, NULL)
          && !netplay_driver_ctl(RARCH_NETPLAY_CTL_IS_SERVER, NULL)
-         && !netplay_driver_ctl(RARCH_NETPLAY_CTL_SKIP_NETPLAY_CALLBACKS, NULL))
+         && !netplay_driver_ctl(RARCH_NETPLAY_CTL_USE_CORE_PACKET_INTERFACE, NULL))
    {
       fill_pathname_join(new_savefile_dir, new_savefile_dir, ".netplay",
          sizeof(new_savefile_dir));