simplify multiple confirm codebug23567

1 files changed, 18 insertions, 26 deletions

diff --git a/src/rabbit_channel.erl b/src/rabbit_channel.erl
index b2e6658b..f7b875a0 100644
--- a/src/rabbit_channel.erl
+++ b/src/rabbit_channel.erl
@@ -1359,35 +1359,27 @@ stop_confirm_timer(State = #ch{confirm_tref = TRef}) ->
     State#ch{confirm_tref = undefined}.
 
 flush_multiple(State = #ch{writer_pid    = WriterPid,
-                           held_confirms = Cs,
-                           unconfirmed   = UC}) ->
+                           held_confirms = Cs}) ->
     case gb_sets:is_empty(Cs) of
-        true -> State;
+        true  -> State#ch{confirm_tref = undefined};
         false -> [First | Rest] = gb_sets:to_list(Cs),
-                 [rabbit_writer:send_command(WriterPid,
-                                             #'basic.ack'{delivery_tag = T}) ||
-                     T <- case Rest of
-                              [] -> [First];
-                              _  -> flush_multiple(
-                                      First, Rest, WriterPid,
-                                      case gb_sets:is_empty(UC) of
-                                          false -> gb_sets:smallest(UC);
-                                          true  -> gb_sets:largest(Cs) + 1
-                                      end)
-                          end],
+                 {Mult, Inds} = find_consecutive_sequence(First, Rest),
+                 ok = rabbit_writer:send_command(
+                        WriterPid,
+                        #'basic.ack'{delivery_tag = Mult, multiple = true}),
+                 ok = lists:foldl(
+                        fun(T, ok) -> rabbit_writer:send_command(
+                                        WriterPid,
+                                        #'basic.ack'{delivery_tag = T})
+                        end, ok, Inds),
                  State#ch{held_confirms = gb_sets:new(),
                           confirm_tref  = undefined}
     end.
 
-flush_multiple(Prev, [Cur | Rest], WriterPid, SNA) ->
-    ExpNext = Prev + 1,
-    case {SNA >= Cur, Cur} of
-        {true, ExpNext} -> flush_multiple(Cur, Rest, WriterPid, SNA);
-        _               -> flush_multiple(Prev, [], WriterPid, SNA),
-                           [Cur | Rest]
-    end;
-flush_multiple(Prev, [], WriterPid, _) ->
-    ok = rabbit_writer:send_command(WriterPid,
-                                    #'basic.ack'{delivery_tag = Prev,
-                                                 multiple = true}),
-    [].
+%% Find longest sequence of consecutive numbers at the beginning.
+find_consecutive_sequence(Last, []) ->
+    {Last, []};
+find_consecutive_sequence(Last, [N | Ns]) when N == (Last + 1) ->
+    find_consecutive_sequence(N, Ns);
+find_consecutive_sequence(Last, Ns) ->
+    {Last, Ns}.