util/pubsub.lua

   1
   2 local ipairs, pairs, setmetatable, type =
   3         ipairs, pairs, setmetatable, type;
   4
   5 module "pubsub"
   6
   7 local pubsub_node_mt = { __index = _M };
   8
   9 function new_node(name)
  10         return setmetatable({ name = name, subscribers = {} }, pubsub_node_mt);
  11 end
  12
  13 function set_subscribers(node, subscribers_list, list_type)
  14         local subscribers = node.subscribers;
  15
  16         if list_type == "array" then
  17                 for _, jid in ipairs(subscribers_list) do
  18                         if not subscribers[jid] then
  19                                 node:add_subscriber(jid);
  20                         end
  21                 end
  22         elseif (not list_type) or list_type == "set" then
  23                 for jid in pairs(subscribers_list) do
  24                         if type(jid) == "string" then
  25                                 node:add_subscriber(jid);
  26                         end
  27                 end
  28         end
  29 end
  30
  31 function get_subscribers(node)
  32         return node.subscribers;
  33 end
  34
  35 function publish(node, item, dispatcher, data)
  36         local subscribers = node.subscribers;
  37         for i = 1,#subscribers do
  38                 item.attr.to = subscribers[i];
  39                 dispatcher(data, item);
  40         end
  41 end
  42
  43 function add_subscriber(node, jid)
  44         local subscribers = node.subscribers;
  45         if not subscribers[jid] then
  46                 local space = #subscribers;
  47                 subscribers[space] = jid;
  48                 subscribers[jid] = space;
  49         end
  50 end
  51
  52 function remove_subscriber(node, subscriber)
  53         local subscribers = node.subscribers;
  54         if subscribers[jid] then
  55                 subscribers[subscribers[jid]] = nil;
  56                 subscribers[jid] = nil;
  57         end
  58 end
  59
  60 return _M;