Let ejabberd_sm mark copied messages

When multiple resources have the same (highest) priority, ejabberd_sm
dispatches messages addressed to the bare JID (or to an unavailable
resource) to each of these resources.  Such messages are now marked with
an 'sm_copy' flag for all but one of the resources.  This makes it
easier for other modules to identify those duplicates.

Resolves #1356.

src/ejabberd_sm.erl

@@ -570,9 +570,9 @@ route_message(From, To, Packet, Type) ->
     LServer = To#jid.lserver,
     PrioRes = get_user_present_resources(LUser, LServer),
     case catch lists:max(PrioRes) of
-      {Priority, _R}
-	  when is_integer(Priority), Priority >= 0 ->
-	  lists:foreach(fun ({P, R}) when P == Priority;
+      {MaxPrio, MaxRes}
+	  when is_integer(MaxPrio), MaxPrio >= 0 ->
+	  lists:foreach(fun ({P, R}) when P == MaxPrio;
 					  (P >= 0) and (Type == headline) ->
 				LResource = jid:resourceprep(R),
 				Mod = get_sm_backend(LServer),
@@ -584,7 +584,12 @@ route_message(From, To, Packet, Type) ->
 				      Session = lists:max(Ss),
 				      Pid = element(2, Session#session.sid),
 				      ?DEBUG("sending to process ~p~n", [Pid]),
-				      Pid ! {route, From, To, Packet}
+				      LMaxRes = jid:resourceprep(MaxRes),
+				      Packet1 = maybe_mark_as_copy(Packet,
+								   LResource,
+								   LMaxRes,
+								   P, MaxPrio),
+				      Pid ! {route, From, To, Packet1}
 				end;
 			    %% Ignore other priority:
 			    ({_Prio, _Res}) -> ok
@@ -603,6 +608,16 @@ route_message(From, To, Packet, Type) ->
 	    end
     end.
 
+-spec maybe_mark_as_copy(message(), binary(), binary(), integer(), integer())
+      -> message().
+maybe_mark_as_copy(Packet, R, R, P, P) ->
+    Packet;
+maybe_mark_as_copy(Packet, _, _, P, P) ->
+    Meta = Packet#message.meta,
+    Packet#message{meta = Meta#{sm_copy => true}};
+maybe_mark_as_copy(Packet, _, _, _, _) ->
+    Packet.
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 -spec clean_session_list([#session{}]) -> [#session{}].
 clean_session_list(Ss) ->

src/mod_carboncopy.erl

@@ -153,7 +153,7 @@ send_copies(JID, To, Packet, Direction)->
     {U, S, R} = jid:tolower(JID),
     PrioRes = ejabberd_sm:get_user_present_resources(U, S),
     {_, AvailRs} = lists:unzip(PrioRes),
-    {MaxPrio, MaxRes} = case catch lists:max(PrioRes) of
+    {MaxPrio, _MaxRes} = case catch lists:max(PrioRes) of
 	{Prio, Res} -> {Prio, Res};
 	_ -> {0, undefined}
     end,
@@ -166,19 +166,19 @@ send_copies(JID, To, Packet, Direction)->
     end,
     %% list of JIDs that should receive a carbon copy of this message (excluding the
     %% receiver(s) of the original message
-    TargetJIDs = case {IsBareTo, R} of
-	{true, MaxRes} ->
+    TargetJIDs = case {IsBareTo, Packet} of
+	{true, #message{meta = #{sm_copy := true}}} ->
+	    %% The message was sent to our bare JID, and we currently have
+	    %% multiple resources with the same highest priority, so the session
+	    %% manager routes the message to each of them. We create carbon
+	    %% copies only from one of those resources in order to avoid
+	    %% duplicates.
+	    [];
+	{true, _} ->
 	    OrigTo = fun(Res) -> lists:member({MaxPrio, Res}, PrioRes) end,
 	    [ {jid:make({U, S, CCRes}), CC_Version}
 	     || {CCRes, CC_Version} <- list(U, S),
 		lists:member(CCRes, AvailRs), not OrigTo(CCRes) ];
-	{true, _} ->
-	    %% The message was sent to our bare JID, and we currently have
-	    %% multiple resources with the same highest priority, so the session
-	    %% manager routes the message to each of them. We create carbon
-	    %% copies only from one of those resources (the one where R equals
-	    %% MaxRes) in order to avoid duplicates.
-	    [];
 	{false, _} ->
 	    [ {jid:make({U, S, CCRes}), CC_Version}
 	     || {CCRes, CC_Version} <- list(U, S),

src/mod_mam.erl

@@ -200,12 +200,11 @@ set_room_option(Acc, _Property, _Lang) ->
     Acc.
 
 -spec user_receive_packet(stanza(), ejabberd_c2s:state(), jid(), jid(), jid()) -> stanza().
-user_receive_packet(Pkt, C2SState, JID, Peer, To) ->
+user_receive_packet(Pkt, C2SState, JID, Peer, _To) ->
     LUser = JID#jid.luser,
     LServer = JID#jid.lserver,
-    IsBareCopy = is_bare_copy(JID, To),
     case should_archive(Pkt, LServer) of
-	true when not IsBareCopy ->
+	true ->
 	    NewPkt = strip_my_archived_tag(Pkt, LServer),
 	    case store_msg(C2SState, NewPkt, LUser, LServer, Peer, recv) of
 		{ok, ID} ->
@@ -454,6 +453,8 @@ process_iq(LServer, #iq{from = #jid{luser = LUser}, lang = Lang,
 
 should_archive(#message{type = error}, _LServer) ->
     false;
+should_archive(#message{meta = #{sm_copy := true}}, _LServer) ->
+    false;
 should_archive(#message{body = Body, subject = Subject,
 			type = Type} = Pkt, LServer) ->
     case is_resent(Pkt, LServer) of
@@ -812,38 +813,6 @@ maybe_update_from_to(#message{sub_els = Els} = Pkt, JidRequestor, JidArchive,
 maybe_update_from_to(Pkt, _JidRequestor, _JidArchive, _Peer, chat, _Nick) ->
     Pkt.
 
-is_bare_copy(#jid{luser = U, lserver = S, lresource = R}, To) ->
-    PrioRes = ejabberd_sm:get_user_present_resources(U, S),
-    MaxRes = case catch lists:max(PrioRes) of
-		 {_Prio, Res} when is_binary(Res) ->
-		     Res;
-		 _ ->
-		     undefined
-	     end,
-    IsBareTo = case To of
-		   #jid{lresource = <<"">>} ->
-		       true;
-		   #jid{lresource = LRes} ->
-		       %% Unavailable resources are handled like bare JIDs.
-		       lists:keyfind(LRes, 2, PrioRes) =:= false
-	       end,
-    case {IsBareTo, R} of
-	{true, MaxRes} ->
-	    ?DEBUG("Recipient of message to bare JID has top priority: ~s@~s/~s",
-		   [U, S, R]),
-	    false;
-	{true, _R} ->
-	    %% The message was sent to our bare JID, and we currently have
-	    %% multiple resources with the same highest priority, so the session
-	    %% manager routes the message to each of them. We store the message
-	    %% only from the resource where R equals MaxRes.
-	    ?DEBUG("Additional recipient of message to bare JID: ~s@~s/~s",
-		   [U, S, R]),
-	    true;
-	{false, _R} ->
-	    false
-    end.
-
 -spec send([{binary(), integer(), xmlel()}],
 	   non_neg_integer(), boolean(), iq()) -> iq() | ignore.
 send(Msgs, Count, IsComplete,