seed journal_minus_segment with the original journal

...and modify/remove things in/from it; rather than building a new
journal from scratch.
The result is the same, but this way of doing things a) better
reflects what this function is about, and b) should be more efficient
in the common case where the journal does not contain stale entries

1 files changed, 23 insertions, 22 deletions

diff --git a/src/rabbit_queue_index.erl b/src/rabbit_queue_index.erl
index 5e53e90972..ff2d3360ec 100644
--- a/src/rabbit_queue_index.erl
+++ b/src/rabbit_queue_index.erl
@@ -929,12 +929,13 @@ journal_minus_segment(JEntries, SegEntries) ->
               {Obj, PubsRemovedDelta, AcksRemovedDelta} =
                   journal_minus_segment1(JObj, SegEntry),
               {case Obj of
-                   undefined -> JEntriesOut;
+                   keep      -> JEntriesOut;
+                   undefined -> array:reset(RelSeq, JEntriesOut);
                    _         -> array:set(RelSeq, Obj, JEntriesOut)
                end,
                PubsRemoved + PubsRemovedDelta,
                AcksRemoved + AcksRemovedDelta}
-      end, {array_new(), 0, 0}, JEntries).
+      end, {JEntries, 0, 0}, JEntries).
 
 %% Here, the result is a triple with the first element containing the
 %% item we are adding to or modifying in the (initially fresh) journal
@@ -944,45 +945,45 @@ journal_minus_segment(JEntries, SegEntries) ->
 %% publish or ack is in both the journal and the segment.
 
 %% Both the same. Must be at least the publish
-journal_minus_segment1({?PUB, _Del, no_ack} = Obj,   Obj) ->
+journal_minus_segment1({?PUB, _Del, no_ack} = Obj, Obj) ->
     {undefined, 1, 0};
-journal_minus_segment1({?PUB, _Del, ack} = Obj,      Obj) ->
+journal_minus_segment1({?PUB, _Del, ack} = Obj,    Obj) ->
     {undefined, 1, 1};
 
 %% Just publish in journal
-journal_minus_segment1({?PUB, no_del, no_ack} = Obj, undefined) ->
-    {Obj, 0, 0};
+journal_minus_segment1({?PUB, no_del, no_ack},     undefined) ->
+    {keep, 0, 0};
 
 %% Publish and deliver in journal
-journal_minus_segment1({?PUB, del, no_ack} = Obj,    undefined) ->
-    {Obj, 0, 0};
-journal_minus_segment1({?PUB = Pub, del, no_ack},    {Pub, no_del, no_ack}) ->
+journal_minus_segment1({?PUB, del, no_ack},        undefined) ->
+    {keep, 0, 0};
+journal_minus_segment1({?PUB = Pub, del, no_ack},  {Pub, no_del, no_ack}) ->
     {{no_pub, del, no_ack}, 1, 0};
 
 %% Publish, deliver and ack in journal
-journal_minus_segment1({?PUB, del, ack},             undefined) ->
+journal_minus_segment1({?PUB, del, ack},           undefined) ->
     {undefined, 0, 0};
-journal_minus_segment1({?PUB = Pub, del, ack},       {Pub, no_del, no_ack}) ->
+journal_minus_segment1({?PUB = Pub, del, ack},     {Pub, no_del, no_ack}) ->
     {{no_pub, del, ack}, 1, 0};
-journal_minus_segment1({?PUB = Pub, del, ack},       {Pub, del, no_ack}) ->
+journal_minus_segment1({?PUB = Pub, del, ack},     {Pub, del, no_ack}) ->
     {{no_pub, no_del, ack}, 1, 0};
 
 %% Just deliver in journal
-journal_minus_segment1({no_pub, del, no_ack} = Obj,  {?PUB, no_del, no_ack}) ->
-    {Obj, 0, 0};
-journal_minus_segment1({no_pub, del, no_ack},        {?PUB, del, no_ack}) ->
+journal_minus_segment1({no_pub, del, no_ack},      {?PUB, no_del, no_ack}) ->
+    {keep, 0, 0};
+journal_minus_segment1({no_pub, del, no_ack},      {?PUB, del, no_ack}) ->
     {undefined, 0, 0};
 
 %% Just ack in journal
-journal_minus_segment1({no_pub, no_del, ack} = Obj,  {?PUB, del, no_ack}) ->
-    {Obj, 0, 0};
-journal_minus_segment1({no_pub, no_del, ack},        {?PUB, del, ack}) ->
+journal_minus_segment1({no_pub, no_del, ack},      {?PUB, del, no_ack}) ->
+    {keep, 0, 0};
+journal_minus_segment1({no_pub, no_del, ack},      {?PUB, del, ack}) ->
     {undefined, 0, 1};
 
 %% Deliver and ack in journal
-journal_minus_segment1({no_pub, del, ack} = Obj,     {?PUB, no_del, no_ack}) ->
-    {Obj, 0, 0};
-journal_minus_segment1({no_pub, del, ack},           {?PUB, del, no_ack}) ->
+journal_minus_segment1({no_pub, del, ack},         {?PUB, no_del, no_ack}) ->
+    {keep, 0, 0};
+journal_minus_segment1({no_pub, del, ack},         {?PUB, del, no_ack}) ->
     {{no_pub, no_del, ack}, 0, 0};
-journal_minus_segment1({no_pub, del, ack},           {?PUB, del, ack}) ->
+journal_minus_segment1({no_pub, del, ack},         {?PUB, del, ack}) ->
     {undefined, 0, 1}.