From 5fd1aa0d046aedc4d3b61a150899085ad863ca0f Mon Sep 17 00:00:00 2001
From: Holger Weiss <holger@zedat.fu-berlin.de>
Date: Wed, 16 Dec 2015 00:08:23 +0100
Subject: [PATCH] Advertise MAM in disco info for account/room JID

As per XEP-0313 version 0.2 and newer, advertise the MAM feature in the
service discovery information for the bare account (or MUC room) JID.

Some clients check the server's discovery information instead, so we'll
continue to advertise the feature there as well.
---
 src/mod_mam.erl      | 17 +++++++++++++++--
 src/mod_muc_room.erl |  7 +++++++
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/src/mod_mam.erl b/src/mod_mam.erl
index 54572fb09..dba8b1cbf 100644
--- a/src/mod_mam.erl
+++ b/src/mod_mam.erl
@@ -34,8 +34,8 @@
 -export([start/2, stop/1]).
 
 -export([user_send_packet/4, user_receive_packet/5,
-	 process_iq_v0_2/3, process_iq_v0_3/3, remove_user/2,
-	 remove_user/3, mod_opt_type/1, muc_process_iq/4,
+	 process_iq_v0_2/3, process_iq_v0_3/3, disco_sm_features/5,
+	 remove_user/2, remove_user/3, mod_opt_type/1, muc_process_iq/4,
 	 muc_filter_message/5]).
 
 -include_lib("stdlib/include/ms_transform.hrl").
@@ -88,6 +88,8 @@ start(Host, Opts) ->
 		       muc_filter_message, 50),
     ejabberd_hooks:add(muc_process_iq, Host, ?MODULE,
 		       muc_process_iq, 50),
+    ejabberd_hooks:add(disco_sm_features, Host, ?MODULE,
+		       disco_sm_features, 50),
     ejabberd_hooks:add(remove_user, Host, ?MODULE,
 		       remove_user, 50),
     ejabberd_hooks:add(anonymous_purge_hook, Host, ?MODULE,
@@ -130,6 +132,8 @@ stop(Host) ->
     gen_iq_handler:remove_iq_handler(ejabberd_sm, Host, ?NS_MAM_0),
     gen_iq_handler:remove_iq_handler(ejabberd_local, Host, ?NS_MAM_1),
     gen_iq_handler:remove_iq_handler(ejabberd_sm, Host, ?NS_MAM_1),
+    ejabberd_hooks:delete(disco_sm_features, Host, ?MODULE,
+			  disco_sm_features, 50),
     ejabberd_hooks:delete(remove_user, Host, ?MODULE,
 			  remove_user, 50),
     ejabberd_hooks:delete(anonymous_purge_hook, Host,
@@ -276,6 +280,15 @@ get_xdata_fields(SubEl) ->
 	    []
     end.
 
+disco_sm_features(empty, From, To, Node, Lang) ->
+    disco_sm_features({result, []}, From, To, Node, Lang);
+disco_sm_features({result, OtherFeatures},
+		  #jid{luser = U, lserver = S},
+		  #jid{luser = U, lserver = S}, <<>>, _Lang) ->
+    {result, [?NS_MAM_TMP, ?NS_MAM_0, ?NS_MAM_1 | OtherFeatures]};
+disco_sm_features(Acc, _From, _To, _Node, _Lang) ->
+    Acc.
+
 %%%===================================================================
 %%% Internal functions
 %%%===================================================================
diff --git a/src/mod_muc_room.erl b/src/mod_muc_room.erl
index dd7f78163..1606b593a 100644
--- a/src/mod_muc_room.erl
+++ b/src/mod_muc_room.erl
@@ -4144,6 +4144,13 @@ process_iq_disco_info(_From, get, Lang, StateData) ->
 			     <<"muc_moderated">>, <<"muc_unmoderated">>),
       ?CONFIG_OPT_TO_FEATURE((Config#config.password_protected),
 			     <<"muc_passwordprotected">>, <<"muc_unsecured">>)]
+       ++ case {gen_mod:is_loaded(StateData#state.server_host, mod_mam),
+		Config#config.mam} of
+	    {true, true} ->
+		[?FEATURE(?NS_MAM_0)];
+	    _ ->
+		[]
+	  end
        ++ iq_disco_info_extras(Lang, StateData),
      StateData}.