Push room info to lobby when publicly hosting (#18267)

* Announce netplay player information to the lobby server

This information is optional and merely informational. The lobby
might ignore it (and it ignores it at the current version).

* Display lobby information on player/spectator counts

Author: davidgfnet

intl/msg_hash_us.h

@@ -14213,6 +14213,14 @@ MSG_HASH(
    MSG_NETPLAY_S_HAS_JOINED_WITH_INPUT_DEVICES_S,
    "%.*s has joined with input devices %.*s"
    )
+MSG_HASH(
+   MSG_NETPLAY_PLAYERS_INFO,
+   "%d player(s)"
+   )
+MSG_HASH(
+   MSG_NETPLAY_SPECTATORS_INFO,
+   "%d player(s) (%d spectating)"
+   )
 MSG_HASH(
    MSG_NETPLAY_NOT_RETROARCH,
    "A netplay connection attempt failed because the peer is not running RetroArch, or is running an old version of RetroArch."

menu/cbs/menu_cbs_sublabel.c

@@ -1817,14 +1817,23 @@ static int action_bind_sublabel_netplay_room(file_list_t *list,
 
    if (     string_is_empty(room->subsystem_name)
          || string_is_equal_case_insensitive(room->subsystem_name, "N/A"))
-      snprintf(s + _len, len - _len, "(%08lX)",
+      _len += snprintf(s + _len, len - _len, "(%08lX)\n",
             (unsigned long)(unsigned)room->gamecrc);
    else
    {
       _len += strlcpy(s + _len, "(", len - _len);
       _len += strlcpy(s + _len, room->subsystem_name, len - _len);
-      strlcpy(s + _len, ")", len - _len);
+      _len += strlcpy(s + _len, ")\n", len - _len);
    }
+
+   if (room->spectator_count > 0)
+      _len += snprintf(s + _len, len - _len,
+         msg_hash_to_str(MSG_NETPLAY_SPECTATORS_INFO),
+         room->player_count, room->spectator_count);
+   else if (room->player_count >= 0)
+      _len += snprintf(s + _len, len - _len,
+         msg_hash_to_str(MSG_NETPLAY_PLAYERS_INFO),
+         room->player_count);
    return 0;
 }
 

msg_hash.h

@@ -208,6 +208,8 @@ enum msg_hash_enums
    MSG_NETPLAY_PLAYER_S_LEFT,
    MSG_NETPLAY_S_HAS_JOINED_AS_PLAYER_N,
    MSG_NETPLAY_S_HAS_JOINED_WITH_INPUT_DEVICES_S,
+   MSG_NETPLAY_PLAYERS_INFO,
+   MSG_NETPLAY_SPECTATORS_INFO,
    MSG_NETPLAY_NOT_RETROARCH,
    MSG_NETPLAY_OUT_OF_DATE,
    MSG_NETPLAY_DIFFERENT_VERSIONS,

network/netplay/netplay.h

@@ -72,6 +72,8 @@ struct netplay_room
    int  port;
    int  mitm_port;
    int  host_method;
+   int  player_count;
+   int  spectator_count;
    char nickname[NETPLAY_NICK_LEN];
    char frontend[NETPLAY_HOST_STR_LEN];
    char corename[NETPLAY_HOST_STR_LEN];

network/netplay/netplay_frontend.c

@@ -8400,6 +8400,31 @@ static bool netplay_should_skip(netplay_t *netplay)
       netplay->self_mode >= NETPLAY_CONNECTION_CONNECTED;
 }
 
+static size_t retrieve_client_count(netplay_t *netplay,
+      unsigned *players, unsigned *spectators)
+{
+   size_t i, r = 0;
+
+   for (i = 0; i < netplay->connections_size; i++)
+   {
+      struct netplay_connection *connection = &netplay->connections[i];
+
+      /* We only want info from already connected clients. */
+      if (     (connection->flags & NETPLAY_CONN_FLAG_ACTIVE)
+            && (connection->mode >= NETPLAY_CONNECTION_CONNECTED))
+      {
+         r++;
+         if (connection->mode == NETPLAY_CONNECTION_SPECTATING)
+            (*spectators)++;
+         else if (connection->mode == NETPLAY_CONNECTION_PLAYING
+               || connection->mode == NETPLAY_CONNECTION_SLAVE)
+            (*players)++;
+      }
+   }
+
+   return r;
+}
+
 bool init_netplay_deferred(const char *server, unsigned port, const char *mitm_session)
 {
    net_driver_state_t *net_st = &networking_driver_st;
@@ -8600,6 +8625,8 @@ static void netplay_announce(netplay_t *netplay)
    int mitm_custom_port             = 0;
    int is_mitm                      = 0;
    uint32_t content_crc             = 0;
+   unsigned players                 = 0;
+   unsigned spectators              = 0;
    net_driver_state_t *net_st       = &networking_driver_st;
    struct netplay_room *host_room   = &net_st->host_room;
    struct retro_system_info *system = &runloop_state_get_ptr()->system.info;
@@ -8678,6 +8705,15 @@ static void netplay_announce(netplay_t *netplay)
    else
       net_http_urlencode(&mitm_custom_addr, "");
 
+   /* Purely informational, should not be used to guess if a host is full. */
+   retrieve_client_count(netplay, &players, &spectators);
+
+   if (netplay->self_mode == NETPLAY_CONNECTION_SPECTATING)
+      spectators++;
+   if (netplay->self_mode == NETPLAY_CONNECTION_PLAYING
+         || netplay->self_mode == NETPLAY_CONNECTION_SLAVE)
+      players++;
+
    /* Estimated to a maximum of 3062 bytes. */
    snprintf(buf, sizeof(buf),
       "username=%s&"
@@ -8695,7 +8731,9 @@ static void netplay_announce(netplay_t *netplay)
       "subsystem_name=%s&"
       "mitm_session=%s&"
       "mitm_custom_addr=%s&"
-      "mitm_custom_port=%d",
+      "mitm_custom_port=%d&"
+      "player_count=%d&"
+      "spectator_count=%d",
       username,
       corename,
       coreversion,
@@ -8711,7 +8749,9 @@ static void netplay_announce(netplay_t *netplay)
       subsystemname,
       mitm_session,
       mitm_custom_addr,
-      mitm_custom_port);
+      mitm_custom_port,
+      players,
+      spectators);
 
    if (task_push_http_post_transfer(FILE_PATH_LOBBY_LIBRETRO_URL "add", buf,
          true, NULL, netplay_announce_cb, NULL))

network/netplay/netplay_room_parse.c

@@ -223,6 +223,10 @@ static bool netplay_json_object_member(void *ctx, const char *p_value,
             p_ctx->cur_member_bool   = &net_st->rooms_data->cur->connectable;
          else if (string_is_equal(p_value, "is_retroarch"))
             p_ctx->cur_member_bool   = &net_st->rooms_data->cur->is_retroarch;
+         else if (string_is_equal(p_value, "player_count"))
+            p_ctx->cur_member_int    = &net_st->rooms_data->cur->player_count;
+         else if (string_is_equal(p_value, "spectator_count"))
+            p_ctx->cur_member_int    = &net_st->rooms_data->cur->spectator_count;
       }
    }