For pubsub items with max_item = 1 use order by in sql queries

src/gen_pubsub_node.erl

@@ -186,6 +186,9 @@
 -callback get_last_items(nodeIdx(), jid(), undefined | rsm_set()) ->
     {result, [pubsubItem()]}.
 
+-callback get_only_item(nodeIdx(), jid()) ->
+    {result, [pubsubItem()]}.
+
 -callback get_item(NodeIdx :: nodeIdx(),
 	ItemId :: itemId(),
 	JID :: jid(),

src/mod_pubsub.erl

@@ -2151,6 +2151,21 @@ get_last_items(Host, Type, Nidx, LJID, Count) when Count > 1 ->
 get_last_items(_Host, _Type, _Nidx, _LJID, _Count) ->
     [].
 
+-spec get_only_item(host(), binary(), nodeIdx(), ljid()) -> [#pubsub_item{}].
+get_only_item(Host, Type, Nidx, LJID) ->
+    case get_cached_item(Host, Nidx) of
+	undefined ->
+	    case node_action(Host, Type, get_only_item, [Nidx, LJID]) of
+		{result, Items} when length(Items) < 2 ->
+		    Items;
+		{result, Items} ->
+		    [hd(lists:keysort(#pubsub_item.modification, Items))];
+		_ -> []
+	    end;
+	LastItem ->
+	    [LastItem]
+    end.
+
 %% @doc <p>Return the list of affiliations as an XMPP response.</p>
 -spec get_affiliations(host(), binary(), jid(), [binary()]) ->
 			      {result, pubsub()} | {error, stanza_error()}.
@@ -3031,7 +3046,13 @@ c2s_handle_info(C2SState, _) ->
 send_items(Host, Node, Nidx, Type, Options, LJID, Number) ->
     send_items(Host, Node, Nidx, Type, Options, Host, LJID, LJID, Number).
 send_items(Host, Node, Nidx, Type, Options, Publisher, SubLJID, ToLJID, Number) ->
-    case get_last_items(Host, Type, Nidx, SubLJID, Number) of
+    Items = case max_items(Host, Options) of
+		1 ->
+		    get_only_item(Host, Type, Nidx, SubLJID);
+		_ ->
+		    get_last_items(Host, Type, Nidx, SubLJID, Number)
+	    end,
+    case Items of
 	[] ->
 	    ok;
 	Items ->

src/node_flat.erl

@@ -46,7 +46,7 @@
     get_subscriptions/2, set_subscriptions/4,
     get_pending_nodes/2, get_states/1, get_state/2,
     set_state/1, get_items/7, get_items/3, get_item/7,
-    get_last_items/3,
+    get_last_items/3, get_only_item/2,
     get_item/2, set_item/1, get_item_name/3, node_to_path/1,
     path_to_node/1, can_fetch_item/2, is_subscribed/1, transform/1]).
 
@@ -812,6 +812,9 @@ get_items(Nidx, JID, AccessModel, PresenceSubscription, RosterGroup, _SubId, RSM
 	    get_items(Nidx, JID, RSM)
     end.
 
+get_only_item(Nidx, From) ->
+    get_last_items(Nidx, From, 1).
+
 get_last_items(Nidx, _From, Count) when Count > 0 ->
     Items = mnesia:index_read(pubsub_item, Nidx, #pubsub_item.nodeidx),
     LastItems = lists:reverse(lists:keysort(#pubsub_item.modification, Items)),

src/node_flat_sql.erl

@@ -51,7 +51,8 @@
     set_state/1, get_items/7, get_items/3, get_item/7,
     get_item/2, set_item/1, get_item_name/3, node_to_path/1,
     path_to_node/1,
-    get_entity_subscriptions_for_send_last/2, get_last_items/3]).
+    get_entity_subscriptions_for_send_last/2, get_last_items/3,
+    get_only_item/2]).
 
 -export([decode_jid/1, encode_jid/1, encode_jid_like/1,
          decode_affiliation/1, decode_subscriptions/1,
@@ -741,6 +742,25 @@ get_last_items(Nidx, _From, Limit) ->
 	    {result, []}
     end.
 
+get_only_item(Nidx, _From) ->
+    SNidx = misc:i2l(Nidx),
+    Query = fun(mssql, _) ->
+	ejabberd_sql:sql_query_t(
+	    [<<"select  itemid, publisher, creation, modification, payload",
+	       " from pubsub_item where nodeid='", SNidx/binary, "'">>]);
+	       (_, _) ->
+		   ejabberd_sql:sql_query_t(
+		       [<<"select itemid, publisher, creation, modification, payload",
+			  " from pubsub_item where nodeid='", SNidx/binary, "'">>])
+	    end,
+    case catch ejabberd_sql:sql_query_t(Query) of
+	{selected, [<<"itemid">>, <<"publisher">>, <<"creation">>,
+		    <<"modification">>, <<"payload">>], RItems} ->
+	    {result, [raw_to_item(Nidx, RItem) || RItem <- RItems]};
+	_ ->
+	    {result, []}
+    end.
+
 get_item(Nidx, ItemId) ->
     case catch ejabberd_sql:sql_query_t(
 		 ?SQL("select @(itemid)s, @(publisher)s, @(creation)s,"

src/node_pep.erl

@@ -42,7 +42,7 @@
     get_subscriptions/2, set_subscriptions/4,
     get_pending_nodes/2, get_states/1, get_state/2,
     set_state/1, get_items/7, get_items/3, get_item/7,
-    get_last_items/3,
+    get_last_items/3, get_only_item/2,
     get_item/2, set_item/1, get_item_name/3, node_to_path/1,
     path_to_node/1, depends/3]).
 
@@ -231,6 +231,9 @@ get_items(Nidx, JID, AccessModel, PresenceSubscription, RosterGroup, SubId, RSM)
 get_last_items(Nidx, From, Count) ->
     node_flat:get_last_items(Nidx, From, Count).
 
+get_only_item(Nidx, From) ->
+    node_flat:get_only_item(Nidx, From).
+
 get_item(Nidx, ItemId) ->
     node_flat:get_item(Nidx, ItemId).
 

src/node_pep_sql.erl

@@ -46,7 +46,8 @@
     set_state/1, get_items/7, get_items/3, get_item/7,
     get_item/2, set_item/1, get_item_name/3, node_to_path/1,
     path_to_node/1, depends/3,
-    get_entity_subscriptions_for_send_last/2, get_last_items/3]).
+    get_entity_subscriptions_for_send_last/2, get_last_items/3,
+    get_only_item/2]).
 
 depends(_Host, _ServerHost, _Opts) ->
     [{mod_caps, hard}].
@@ -218,6 +219,9 @@ get_items(Nidx, JID, AccessModel, PresenceSubscription, RosterGroup, SubId, RSM)
 get_last_items(Nidx, JID, Count) ->
     node_flat_sql:get_last_items(Nidx, JID, Count).
 
+get_only_item(Nidx, JID) ->
+    node_flat_sql:get_only_item(Nidx, JID).
+
 get_item(Nidx, ItemId) ->
     node_flat_sql:get_item(Nidx, ItemId).