Allow @enum when AVP is defined in an inherited dictionary.

3GPP standards (for one) extend the values allowed for RFC 3588
AVP's of type Enumerated. Previously, extending an AVP was only
possible by completely redefining the AVP.

3 files changed, 84 insertions, 33 deletions

diff --git a/lib/diameter/doc/src/diameter_dict.xml b/lib/diameter/doc/src/diameter_dict.xml
index a87f59bad5..cd62f43b44 100644
--- a/lib/diameter/doc/src/diameter_dict.xml
+++ b/lib/diameter/doc/src/diameter_dict.xml
@@ -370,7 +370,11 @@ Integer values can be prefixed with 0x to be interpreted as
 hexidecimal.</p>
 
 <p>
-Can occur 0 or more times (with different values of Name).</p>
+Can occur 0 or more times (with different values of Name).
+The AVP in question can be defined in an inherited dictionary in order
+to introduce additional values.
+An AVP so extended must be referenced by in a <c>@messages</c> or
+<c>@grouped</c> section.</p>
 
 <p>
 Example:</p>
diff --git a/lib/diameter/src/compiler/diameter_codegen.erl b/lib/diameter/src/compiler/diameter_codegen.erl
index 213ba0d22c..38840f592f 100644
--- a/lib/diameter/src/compiler/diameter_codegen.erl
+++ b/lib/diameter/src/compiler/diameter_codegen.erl
@@ -454,9 +454,10 @@ avp(Spec) ->
     Native   = get_value(avp_types, Spec),
     Custom   = get_value(custom_types, Spec),
     Imported = get_value(import_avps, Spec),
-    avp([{N,T} || {N,_,T,_,_} <- Native], Imported, Custom).
+    Enums    = get_value(enums, Spec),
+    avp([{N,T} || {N,_,T,_,_} <- Native], Imported, Custom, Enums).
 
-avp(Native, Imported, Custom) ->
+avp(Native, Imported, Custom, Enums) ->
     Dict = orddict:from_list(Native),
 
     report(native, Dict),
@@ -470,8 +471,8 @@ avp(Native, Imported, Custom) ->
                                    false == lists:member(N, CustomNames)
                            end,
                            Native))
-        ++ lists:flatmap(fun c_imported_avp/1, Imported)
-        ++ lists:flatmap(fun(C) -> c_custom_avp(C, Dict) end, Custom).
+        ++ lists:flatmap(fun(I) -> cs_imported_avp(I, Enums) end, Imported)
+        ++ lists:flatmap(fun(C) -> cs_custom_avp(C, Dict) end, Custom).
 
 c_base_avp({AvpName, T}) ->
     {?clause, [?VAR('T'), ?VAR('Data'), ?ATOM(AvpName)],
@@ -487,23 +488,35 @@ base_avp(AvpName, 'Grouped') ->
 base_avp(_, Type) ->
     ?APPLY(diameter_types, Type, [?VAR('T'), ?VAR('Data')]).
 
-c_imported_avp({Mod, Avps}) ->
-    lists:map(fun(A) -> imported_avp(Mod, A) end, Avps).
+cs_imported_avp({Mod, Avps}, Enums) ->
+    lists:map(fun(A) -> imported_avp(Mod, A, Enums) end, Avps).
 
-imported_avp(_Mod, {AvpName, _, 'Grouped' = T, _, _}) ->
+imported_avp(_Mod, {AvpName, _, 'Grouped' = T, _, _}, _) ->
     c_base_avp({AvpName, T});
 
-imported_avp(Mod, {AvpName, _, _, _, _}) ->
+imported_avp(Mod, {AvpName, _, 'Enumerated' = T, _, _}, Enums) ->
+    case lists:keymember(AvpName, 1, Enums) of
+        true ->
+            c_base_avp({AvpName, T});
+        false ->
+            c_imported_avp(Mod, AvpName)
+    end;
+
+imported_avp(Mod, {AvpName, _, _, _, _}, _) ->
+    c_imported_avp(Mod, AvpName).
+
+c_imported_avp(Mod, AvpName) ->
     {?clause, [?VAR('T'), ?VAR('Data'), ?ATOM(AvpName)],
      [],
      [?APPLY(Mod, avp, [?VAR('T'),
                         ?VAR('Data'),
                         ?ATOM(AvpName)])]}.
 
-c_custom_avp({Mod, Avps}, Dict) ->
-    lists:map(fun(N) -> custom_avp(Mod, N, orddict:fetch(N, Dict)) end, Avps).
+cs_custom_avp({Mod, Avps}, Dict) ->
+    lists:map(fun(N) -> c_custom_avp(Mod, N, orddict:fetch(N, Dict)) end,
+              Avps).
 
-custom_avp(Mod, AvpName, Type) ->
+c_custom_avp(Mod, AvpName, Type) ->
     {?clause, [?VAR('T'), ?VAR('Data'), ?ATOM(AvpName)],
      [],
      [?APPLY(Mod, AvpName, [?VAR('T'), ?ATOM(Type), ?VAR('Data')])]}.
@@ -516,9 +529,25 @@ f_enumerated_avp(Spec) ->
     {?function, enumerated_avp, 3, enumerated_avp(Spec) ++ [?UNEXPECTED(3)]}.
 
 enumerated_avp(Spec) ->
-    lists:flatmap(fun c_enumerated_avp/1, get_value(enums, Spec)).
+    Enums = get_value(enums, Spec),
+    lists:flatmap(fun cs_enumerated_avp/1, Enums)
+        ++ lists:flatmap(fun({M,Es}) -> enumerated_avp(M, Es, Enums) end,
+                         get_value(import_enums, Spec)).
+
+enumerated_avp(Mod, Es, Enums) ->
+    lists:flatmap(fun({N,_}) ->
+                          cs_enumerated_avp(lists:keymember(N, 1, Enums),
+                                            Mod,
+                                            N)
+                  end,
+                  Es).
+
+cs_enumerated_avp(true, Mod, Name) ->
+    [c_imported_avp(Mod, Name)];
+cs_enumerated_avp(false, _, _) ->
+    [].
 
-c_enumerated_avp({AvpName, Values}) ->
+cs_enumerated_avp({AvpName, Values}) ->
     lists:flatmap(fun(V) -> c_enumerated_avp(AvpName, V) end, Values).
 
 c_enumerated_avp(AvpName, {I,_}) ->
@@ -616,10 +645,12 @@ f_empty_value(Spec) ->
     {?function, empty_value, 1, empty_value(Spec)}.
 
 empty_value(Spec) ->
+    Imported = lists:flatmap(fun avps/1, get_value(import_enums, Spec)),
     Groups = get_value(grouped, Spec)
         ++ lists:flatmap(fun avps/1, get_value(import_groups, Spec)),
-    Enums = get_value(enums, Spec)
-        ++ lists:flatmap(fun avps/1, get_value(import_enums, Spec)),
+    Enums = [T || {N,_} = T <- get_value(enums, Spec),
+                  not lists:keymember(N, 1, Imported)]
+        ++ Imported,
     lists:map(fun c_empty_value/1, Groups ++ Enums)
         ++ [{?clause, [?VAR('Name')], [], [?CALL(empty, [?VAR('Name')])]}].
 
diff --git a/lib/diameter/src/compiler/diameter_spec_util.erl b/lib/diameter/src/compiler/diameter_spec_util.erl
index 322d53a199..b60886b678 100644
--- a/lib/diameter/src/compiler/diameter_spec_util.erl
+++ b/lib/diameter/src/compiler/diameter_spec_util.erl
@@ -39,11 +39,11 @@ parse(Path, Options) ->
     {ok, B} = file:read_file(Path),
     Chunks = chunk(B),
     Spec = make_spec(Chunks),
-    true = enums_defined(Spec),   %% sanity checks
-    true = groups_defined(Spec),  %%
+    true = groups_defined(Spec),  %% sanity checks
     true = customs_defined(Spec), %%
     Full = import_enums(import_groups(import_avps(insert_codes(Spec),
                                                   Options))),
+    true = enums_defined(Full),   %% sanity checks
     true = v_flags_set(Spec),
     Full.
 
@@ -243,35 +243,48 @@ get_value(Key, Spec) ->
 %% with an appropriate type.
 
 enums_defined(Spec) ->
-    is_defined(Spec, 'Enumerated', enums).
+    Avps = get_value(avp_types, Spec),
+    Import = get_value(import_enums, Spec),
+    lists:all(fun({N,_}) ->
+                      true = enum_defined(N, Avps, Import)
+              end,
+              get_value(enums, Spec)).
 
-groups_defined(Spec) ->
-    is_defined(Spec, 'Grouped', grouped).
+enum_defined(Name, Avps, Import) ->
+    case lists:keyfind(Name, 1, Avps) of
+        {Name, _, 'Enumerated', _, _} ->
+            true;
+        {Name, _, T, _, _} ->
+            ?ERROR({avp_has_wrong_type, Name, 'Enumerated', T});
+        false ->
+            lists:any(fun({_,Is}) -> lists:keymember(Name, 1, Is) end, Import)
+                orelse ?ERROR({avp_not_defined, Name, 'Enumerated'})
+    end.
+%% Note that an AVP is imported only if referenced by a message or
+%% grouped AVP, so the final branch will fail if an enum definition is
+%% extended without this being the case.
 
-is_defined(Spec, Type, Key) ->
+groups_defined(Spec) ->
     Avps = get_value(avp_types, Spec),
-    lists:all(fun(T) -> true = is_local(name(Key, T), Type, Avps) end,
-              get_value(Key, Spec)).
+    lists:all(fun({N,_,_,_}) -> true = group_defined(N, Avps) end,
+              get_value(grouped, Spec)).
 
-name(enums,   {N,_})     -> N;
-name(grouped, {N,_,_,_}) -> N.
-
-is_local(Name, Type, Avps) ->
+group_defined(Name, Avps) ->
     case lists:keyfind(Name, 1, Avps) of
-        {Name, _, Type, _, _} ->
+        {Name, _, 'Grouped', _, _} ->
             true;
         {Name, _, T, _, _} ->
-            ?ERROR({avp_has_wrong_type, Name, Type, T});
+            ?ERROR({avp_has_wrong_type, Name, 'Grouped', T});
         false ->
-            ?ERROR({avp_not_defined, Name, Type})
+            ?ERROR({avp_not_defined, Name, 'Grouped'})
     end.
 
 customs_defined(Spec) ->
     Avps = get_value(avp_types, Spec),
-    lists:all(fun(A) -> true = is_local(A, Avps) end,
+    lists:all(fun(A) -> true = custom_defined(A, Avps) end,
               lists:flatmap(fun last/1, get_value(custom_types, Spec))).
 
-is_local(Name, Avps) ->
+custom_defined(Name, Avps) ->
     case lists:keyfind(Name, 1, Avps) of
         {Name, _, T, _, _} when T == 'Grouped';
                                 T == 'Enumerated' ->
@@ -510,6 +523,9 @@ choose(false, _, X) -> X.
 %% ------------------------------------------------------------------------
 %% import_groups/1
 %% import_enums/1
+%%
+%% For each inherited module, store the content of imported AVP's of
+%% type grouped/enumerated in a new key.
 
 import_groups(Spec) ->
     orddict:store(import_groups, import(grouped, Spec), Spec).