fix: Optimizes hot paths in prosody modules, string comparisons.

resources/prosody-plugins/mod_muc_allowners.lua

 local jid = require "util.jid";
 local um_is_admin = require "core.usermanager".is_admin;
-local is_healthcheck_room = module:require "util".is_healthcheck_room;
+local util = module:require "util";
+local is_healthcheck_room = util.is_healthcheck_room;
+local extract_subdomain = util.extract_subdomain;
 
 local moderated_subdomains;
 local moderated_rooms;
 --      -> true, room_name, subdomain
 --      -> true, room_name, nil (if no subdomain is used for the room)
 local function is_moderated(room_jid)
+    if #moderated_subdomains == 0 and #moderated_rooms == 0 then
+        return false;
+    end
+
     local room_node = jid.node(room_jid);
     -- parses bare room address, for multidomain expected format is:
     -- [subdomain]roomName@conference.domain
-    local target_subdomain, target_room_name = room_node:match("^%[([^%]]+)%](.+)$");
-
+    local target_subdomain, target_room_name = extract_subdomain(room_node);
     if target_subdomain then
         if moderated_subdomains:contains(target_subdomain) then
             return true, target_room_name, target_subdomain;

resources/prosody-plugins/mod_muc_call.lua

 local ext_events = module:require "ext_events"
 local jid = require "util.jid"
+local extract_subdomain = module:require "util".extract_subdomain;
 
 -- Options and configuration
 local poltergeist_component = module:get_option_string(
     local node, _, _ = jid.split(room_jid)
     if not node then return nil end
 
-    local target_subdomain, target_node = node:match("^%[([^%]]+)%](.+)$")
+    local target_subdomain, target_node = extract_subdomain(node);
 
     if not(target_node or target_subdomain) then
         return "https://"..muc_domain_base.."/"..node

resources/prosody-plugins/token/util.lib.lua

 local json_safe = require "cjson.safe";
 local path = require "util.paths";
 local sha256 = require "util.hashes".sha256;
-local http_get_with_retry = module:require "util".http_get_with_retry;
+local main_util = module:require "util";
+local http_get_with_retry = main_util.http_get_with_retry;
+local extract_subdomain = main_util.extract_subdomain;
 
 local nr_retries = 3;
 
     local room_node = jid.node(room_address);
     -- parses bare room address, for multidomain expected format is:
     -- [subdomain]roomName@conference.domain
-    local target_subdomain, target_room = room_node:match("^%[([^%]]+)%](.+)$");
+    local target_subdomain, target_room = extract_subdomain(room_node);
 
     -- if we have '*' as room name in token, this means all rooms are allowed
     -- so we will use the actual name of the room when constructing strings

resources/prosody-plugins/util.lib.lua

 -- (e.g. from room1@conference.foo.example.com/res returns (room1, example.com, res, foo))
 local function room_jid_split_subdomain(room_jid)
     local node, host, resource = jid.split(room_jid);
+
+    -- optimization, skip matching if there is no subdomain or it is not the muc component address at all
+    if host == muc_domain or not starts_with(host, muc_domain_prefix) then
+        return node, host, resource;
+    end
+
     local target_subdomain = host and host:match(target_subdomain_pattern);
     return node, host, resource, target_subdomain
 end
 
         return room_jid;
     end
-    local target_subdomain, target_node = node:match("^%[([^%]]+)%](.+)$");
+
+    local target_subdomain, target_node = extract_subdomain(node);
     if not (target_node and target_subdomain) then
         -- module:log("debug", "Not rewriting... unexpected node format: %s", node);
         return room_jid;
     end
+
     -- Ok, rewrite room_jid address to pretty format
     local new_node, new_host, new_resource = target_node, muc_domain_prefix..".".. target_subdomain.."."..muc_domain_base, resource;
     room_jid = jid.join(new_node, new_host, new_resource);
     end
 end
 
+--- Extracts the subdomain and room name from internal jid node [foo]room1
+-- @return subdomain(optional, if extracted or nil), the room name
+function extract_subdomain(room_node)
+    -- optimization, skip matching if there is no subdomain, no [subdomain] part in the beginning of the node
+    if not starts_with(room_node, '[') then
+        return room_node;
+    end
+
+    return room_node:match("^%[([^%]]+)%](.+)$");
+end
+
 function starts_with(str, start)
     return str:sub(1, #start) == start
 end
 end
 
 return {
+    extract_subdomain = extract_subdomain;
     is_feature_allowed = is_feature_allowed;
     is_healthcheck_room = is_healthcheck_room;
     get_room_from_jid = get_room_from_jid;