Refactor.

Author: Simon MacMullen

src/rabbit_runtime_parameters.erl

@@ -140,7 +140,7 @@ list(VHost)               -> list(VHost, '_').
 list_component(Component) -> list('_',   Component).
 
 list(VHost, Component) ->
-    assert_vhost(VHost),
+    rabbit_vhost:assert(VHost),
     Match = #runtime_parameters{key = {VHost, Component, '_'}, _ = '_'},
     [p(P) || #runtime_parameters{key = {_VHost, Comp, _Name}} = P <-
                  mnesia:dirty_match_object(?TABLE, Match),
@@ -149,12 +149,6 @@ list(VHost, Component) ->
 list_formatted(VHost) ->
     [pset(value, format(pget(value, P)), P) || P <- list(VHost)].
 
-assert_vhost('_')   -> ok;
-assert_vhost(VHost) -> case rabbit_vhost:exists(VHost) of
-                           true  -> ok;
-                           false -> throw({error, {no_such_vhost, VHost}})
-                       end.
-
 lookup(VHost, Component, Name) ->
     case lookup0(VHost, Component, Name, rabbit_misc:const(not_found)) of
         not_found -> not_found;

src/rabbit_vhost.erl

@@ -20,7 +20,7 @@
 
 %%----------------------------------------------------------------------------
 
--export([add/1, delete/1, exists/1, list/0, with/2]).
+-export([add/1, delete/1, exists/1, list/0, with/2, assert/1]).
 -export([info/1, info/2, info_all/0, info_all/1]).
 
 -ifdef(use_specs).
@@ -30,6 +30,7 @@
 -spec(exists/1 :: (rabbit_types:vhost()) -> boolean()).
 -spec(list/0 :: () -> [rabbit_types:vhost()]).
 -spec(with/2 :: (rabbit_types:vhost(), rabbit_misc:thunk(A)) -> A).
+-spec(assert/1 :: (rabbit_types:vhost()) -> 'ok').
 
 -spec(info/1 :: (rabbit_types:vhost()) -> rabbit_types:infos()).
 -spec(info/2 :: (rabbit_types:vhost(), rabbit_types:info_keys())
@@ -120,6 +121,13 @@ with(VHostPath, Thunk) ->
             end
     end.
 
+%% Like with/2 but outside an Mnesia tx
+assert('_')       -> ok;
+assert(VHostPath) -> case rabbit_vhost:exists(VHostPath) of
+                         true  -> ok;
+                         false -> throw({error, {no_such_vhost, VHostPath}})
+                     end.
+
 %%----------------------------------------------------------------------------
 
 infos(Items, X) -> [{Item, i(Item, X)} || Item <- Items].