Reinstate optimisations, plus a bit of abstraction. This entails an API change in the return type of rabbit_policy:get/2.

3 files changed, 23 insertions, 16 deletions

diff --git a/src/rabbit_amqqueue.erl b/src/rabbit_amqqueue.erl
index 0673ff8ebd..31c0268f99 100644
--- a/src/rabbit_amqqueue.erl
+++ b/src/rabbit_amqqueue.erl
@@ -631,8 +631,7 @@ forget_all_durable(Node) ->
                      internal_delete1(Name)) ||
                       #amqqueue{name = Name, pid = Pid} = Q <- Qs,
                       node(Pid) =:= Node,
-                      rabbit_policy:get(<<"ha-mode">>, Q)
-                          =:= {error, not_found}],
+                      rabbit_policy:get(<<"ha-mode">>, Q) =:= undefined],
                   ok
           end),
     ok.
diff --git a/src/rabbit_exchange.erl b/src/rabbit_exchange.erl
index bdb0f5db48..fc13151958 100644
--- a/src/rabbit_exchange.erl
+++ b/src/rabbit_exchange.erl
@@ -347,13 +347,11 @@ route1(Delivery, Decorators,
            lists:foldl(fun process_route/2, {WorkList, SeenXs, QNames},
                        AlternateDests ++ DecorateDests  ++ ExchangeDests)).
 
-process_alternate(X = #exchange{name = XName, arguments = Args}, []) ->
-    case rabbit_misc:r_arg(XName, exchange, Args, <<"alternate-exchange">>) of
-        undefined -> case rabbit_policy:get(<<"alternate-exchange">>, X) of
-                         {ok, AName} -> [rabbit_misc:r(XName, exchange, AName)];
-                         {error, _}  -> []
-                     end;
-        AName     -> [AName]
+process_alternate(X = #exchange{name = XName}, []) ->
+    case rabbit_policy:get_arg(
+           <<"alternate-exchange">>, <<"alternate-exchange">>, X) of
+        undefined -> [];
+        AName     -> [rabbit_misc:r(XName, exchange, AName)]
     end;
 process_alternate(_X, _Results) ->
     [].
diff --git a/src/rabbit_policy.erl b/src/rabbit_policy.erl
index 0785d27802..d371ac4db7 100644
--- a/src/rabbit_policy.erl
+++ b/src/rabbit_policy.erl
@@ -26,7 +26,7 @@
 
 -export([register/0]).
 -export([invalidate/0, recover/0]).
--export([name/1, get/2, set/1]).
+-export([name/1, get/2, get_arg/3, set/1]).
 -export([validate/4, notify/4, notify_clear/3]).
 -export([parse_set/6, set/6, delete/2, lookup/2, list/0, list/1,
          list_formatted/1, info_keys/0]).
@@ -62,15 +62,25 @@ get(Name, #exchange{policy = Policy}) -> get0(Name, Policy);
 get(Name, EntityName = #resource{virtual_host = VHost}) ->
     get0(Name, match(EntityName, list(VHost))).
 
-get0(_Name, undefined) -> {error, not_found};
+get0(_Name, undefined) -> undefined;
 get0(Name, List)       -> case pget(definition, List) of
-                              undefined -> {error, not_found};
-                              Policy    -> case pget(Name, Policy) of
-                                               undefined -> {error, not_found};
-                                               Value    -> {ok, Value}
-                                           end
+                              undefined -> undefined;
+                              Policy    -> pget(Name, Policy)
                           end.
 
+%% Many heads for optimisation
+get_arg(_AName, _PName,     #exchange{arguments = [], policy = undefined}) ->
+    undefined;
+get_arg(_AName,  PName, X = #exchange{arguments = []}) ->
+    get(PName, X);
+get_arg(AName,  _PName,     #exchange{arguments = Args, policy = undefined}) ->
+    rabbit_misc:table_lookup(Args, AName);
+get_arg(AName,   PName, X = #exchange{arguments = Args}) ->
+    case rabbit_misc:table_lookup(Args, AName) of
+        undefined -> get(PName, X);
+        Arg       -> Arg
+    end.
+
 %%----------------------------------------------------------------------------
 
 %% Gets called during upgrades - therefore must not assume anything about the