Stop match earlier, and added some comments

1 files changed, 25 insertions, 4 deletions

diff --git a/src/rabbit_exchange_type_headers.erl b/src/rabbit_exchange_type_headers.erl
index 60825086f5..444d507c7e 100644
--- a/src/rabbit_exchange_type_headers.erl
+++ b/src/rabbit_exchange_type_headers.erl
@@ -85,31 +85,52 @@ headers_match(Args, Data) ->
     MK = parse_x_match(rabbit_misc:table_lookup(Args, <<"x-match">>)),
     headers_match(Args, Data, true, false, MK).
 
-headers_match([], _Data, AllMatch, _AnyMatch, all) ->
-    AllMatch;
-headers_match([], _Data, _AllMatch, AnyMatch, any) ->
-    AnyMatch;
+% A bit less horrendous algorithm :)
+headers_match(_, _, false, _, all) -> false;
+headers_match(_, _, _, true, any) -> true;
+
+% No more bindings, return current state
+headers_match([], _Data, AllMatch, _AnyMatch, all) -> AllMatch;
+headers_match([], _Data, _AllMatch, AnyMatch, any) -> AnyMatch;
+
+% Delete bindings starting with x-
 headers_match([{<<"x-", _/binary>>, _PT, _PV} | PRest], Data,
               AllMatch, AnyMatch, MatchKind) ->
     headers_match(PRest, Data, AllMatch, AnyMatch, MatchKind);
+
+% No more data, but still bindings, false with all
 headers_match(_Pattern, [], _AllMatch, AnyMatch, MatchKind) ->
     headers_match([], [], false, AnyMatch, MatchKind);
+
+% Data key header not in binding, go next data
 headers_match(Pattern = [{PK, _PT, _PV} | _], [{DK, _DT, _DV} | DRest],
               AllMatch, AnyMatch, MatchKind) when PK > DK ->
     headers_match(Pattern, DRest, AllMatch, AnyMatch, MatchKind);
+
+% Binding key header not in data, false with all, go next binding
 headers_match([{PK, _PT, _PV} | PRest], Data = [{DK, _DT, _DV} | _],
               _AllMatch, AnyMatch, MatchKind) when PK < DK ->
     headers_match(PRest, Data, false, AnyMatch, MatchKind);
+
+%% It's not properly specified, but a "no value" in a
+%% pattern field is supposed to mean simple presence of
+%% the corresponding data field. I've interpreted that to
+%% mean a type of "void" for the pattern field.
 headers_match([{PK, void, _PV} | PRest], [{DK, _DT, _DV} | DRest],
               AllMatch, _AnyMatch, MatchKind) when PK == DK ->
     headers_match(PRest, DRest, AllMatch, true, MatchKind);
+
+% Complete match, true with any, go next
 headers_match([{PK, _PT, PV} | PRest], [{DK, _DT, DV} | DRest],
               AllMatch, _AnyMatch, MatchKind) when PK == DK andalso PV == DV ->
     headers_match(PRest, DRest, AllMatch, true, MatchKind);
+
+% Value does not match, false with all, go next
 headers_match([{PK, _PT, _PV} | PRest], [{DK, _DT, _DV} | DRest],
               _AllMatch, AnyMatch, MatchKind) when PK == DK ->
     headers_match(PRest, DRest, false, AnyMatch, MatchKind).
 
+
 validate(_X) -> ok.
 create(_Tx, _X) -> ok.
 delete(_Tx, _X, _Bs) -> ok.