diameter_spec_util -> diameter_dict_util and adapt to parser

Errors are now detected after the parse with format_error/1
providing understandable error messages, pointing to the
offending line number(s) in the dictionary source.

1 files changed, 1108 insertions, 0 deletions

diff --git a/lib/diameter/src/compiler/diameter_dict_util.erl b/lib/diameter/src/compiler/diameter_dict_util.erl
new file mode 100644
index 0000000000..7c992316f9
--- /dev/null
+++ b/lib/diameter/src/compiler/diameter_dict_util.erl
@@ -0,0 +1,1108 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2010-2011. All Rights Reserved.
+%%
+%% The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved online at http://www.erlang.org/.
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%%
+%% %CopyrightEnd%
+%%
+
+%%
+%% This module turns a dictionary file into the orddict that
+%% diameter_codegen.erl in turn morphs into .erl and .hrl files for
+%% encode and decode of Diameter messages and AVPs.
+%%
+
+-module(diameter_dict_util).
+
+-export([parse/2,
+         format_error/1]).
+
+-include("diameter_vsn.hrl").
+
+-define(RETURN(T), throw({T, ?MODULE, ?LINE})).
+-define(RETURN(T, Args), ?RETURN({T, Args})).
+
+-define(A, list_to_atom).
+-define(L, atom_to_list).
+
+%% ===========================================================================
+%% parse/2
+%% ===========================================================================
+
+-spec parse(File, Opts)
+   -> {ok, orddict:orddict()}
+    | {error, term()}
+ when File :: {path, string()}
+            | string()
+            | binary(),
+      Opts :: list().
+
+parse(File, Opts) ->
+    put({?MODULE, verbose}, lists:member(verbose, Opts)),
+    try
+        {ok, do_parse(File, Opts)}
+    catch
+        {Reason, ?MODULE, _Line} ->
+            {error, Reason}
+    after
+        erase({?MODULE, verbose})
+    end.
+
+%% ===========================================================================
+%% format_error/1
+%% ===========================================================================
+
+format_error({read, Reason}) ->
+    file:format_error(Reason);
+format_error({scan, Reason}) ->
+    diameter_dict_scanner:format_error(Reason);
+format_error({parse, {Line, _Mod, Reason}}) ->
+    lists:flatten(["Line ", integer_to_list(Line), ", ", Reason]);
+
+format_error(T) ->
+    {Fmt, As} = fmt(T),
+    lists:flatten(io_lib:format(Fmt, As)).
+
+fmt({avp_code_already_defined, [Code, false, Name, Line, L]}) ->
+    {"AVP ~p (~s) at line ~p already defined at line ~p",
+     [Code, Name, Line, L]};
+
+fmt({Reason, As}) ->
+    {fmt(Reason), As};
+
+fmt(avp_code_already_defined) ->
+    "AVP ~p/~p (~s) at line ~p already defined at line ~p";
+
+fmt(imported_avp_already_defined) ->
+    "AVP ~s imported by @inherits ~p at line ~p defined at line ~p";
+fmt(duplicate_import) ->
+    "AVP ~s is imported by more than one @inherits, both at line ~p "
+    "and at line ~p";
+
+fmt(duplicate_section) ->
+    "Section @~s at line ~p already declared at line ~p";
+
+fmt(already_declared) ->
+    "Section @~p ~s at line ~p already declared at line ~p";
+
+fmt(inherited_avp_already_defined) ->
+    "AVP ~s inherited at line ~p defined in @avp_types at line ~p";
+fmt(avp_already_defined) ->
+    "AVP ~s at line ~p already in @~p at line ~p";
+fmt(key_already_defined) ->
+    "Value for ~s:~s in @~p at line ~p already provided at line ~p";
+
+fmt(messages_without_id) ->
+    "@messages at line ~p but @id not declared";
+
+fmt(avp_name_already_defined) ->
+    "AVP ~s at line ~p already defined at line ~p";
+fmt(avp_has_unknown_type) ->
+    "AVP ~s at line ~p defined with unknown type ~s";
+fmt(avp_has_invalid_flag) ->
+    "AVP ~s at line ~p specifies invalid flag ~c";
+fmt(avp_has_duplicate_flag) ->
+    "AVP ~s at line ~p specifies duplicate flag ~c";
+fmt(avp_has_vendor_id) ->
+    "AVP ~s at line ~p does not specify V flag "
+    "but is assigned vendor id ~p at line ~p";
+fmt(avp_has_no_vendor) ->
+    "AVP ~s at line ~p specifies V flag "
+    "but neither @vendor_avp_id nor @vendor supplies a value";
+
+fmt(group_already_defined) ->
+    "Group ~s at line ~p already defined at line ~p";
+fmt(grouped_avp_code_mismatch) ->
+    "AVP ~s at line ~p has with code ~p "
+    "but @avp_types specifies ~p at line ~p";
+fmt(grouped_avp_has_wrong_type) ->
+    "Grouped AVP ~s at line ~p defined with type ~s at line ~p";
+fmt(grouped_avp_not_defined) ->
+    "Grouped AVP ~s on line ~p not defined in @avp_types";
+fmt(grouped_vendor_id_without_flag) ->
+    "Grouped AVP ~s at line ~p has vendor id "
+    "but definition at line ~p does not specify V flag";
+fmt(grouped_vendor_id_mismatch) ->
+    "Grouped AVP ~s at line ~p has vendor id ~p "
+    "but ~p specified at line ~p";
+
+fmt(message_name_already_defined) ->
+    "Message ~s at line ~p already defined at line ~p";
+fmt(message_code_already_defined) ->
+    "~s message with code ~p at line ~p already defined at line ~p";
+fmt(message_has_duplicate_flag) ->
+    "Message ~s has duplicate flag ~s at line ~p";
+fmt(message_application_id_mismatch) ->
+    "Message ~s has application id ~p at line ~p "
+    "but @id specifies ~p at line ~p";
+
+fmt(invalid_avp_order) ->
+    "AVP reference ~c~s~c at line ~p breaks fixed/required/optional order";
+fmt(invalid_qualifier) ->
+    "Qualifier ~p*~p at line ~p has Min > Max";
+fmt(avp_already_referenced) ->
+    "AVP ~s at line ~p already referenced at line ~p";
+
+fmt(message_missing) ->
+    "~s message at line ~p but no ~s message is defined";
+
+fmt(requested_avp_not_found) ->
+    "@inherit ~s at line ~p requests AVP ~s at line ~p "
+    "but module does not define that AVP";
+
+fmt(enumerated_avp_has_wrong_local_type) ->
+    "Enumerated AVP ~s in @enum at line ~p defined with type ~s at line ~p";
+fmt(enumerated_avp_has_wrong_inherited_type) ->
+    "Enumerated AVP ~s in @enum at line ~p "
+    "inherited with type ~s from module ~s at line ~p";
+fmt(enumerated_avp_not_defined) ->
+    "Enumerated AVP ~s in @enum at line ~p neither defined nor inherited";
+
+fmt(avp_not_defined) ->
+    "AVP ~s referenced at line ~p neither defined nor inherited";
+
+fmt(beam_not_on_path) ->
+    "Module ~s not found";
+
+fmt(recompile) ->
+    "Module ~p appears to have been compiler with an incompatible "
+    "version of the dictionary compiler and must be recompiled";
+fmt(no_dict) ->
+    "Module ~p does not appear to be a diameter dictionary".
+
+%% ===========================================================================
+%% ===========================================================================
+
+do_parse(File, Opts) ->
+    Bin  = do([fun read/1, File], read),
+    Toks = do([fun diameter_dict_scanner:scan/1, Bin], scan),
+    Tree = do([fun diameter_dict_parser:parse/1, Toks], parse),
+    make_dict(Tree, Opts).
+
+do([F|A], E) ->
+    case apply(F,A) of
+        {ok, T} ->
+            T;
+        {error, Reason} ->
+            ?RETURN({E, Reason})
+    end.
+
+read({path, Path}) ->
+    file:read_file(Path);
+read(File) ->
+    {ok, File}.
+
+make_dict(Parse, Opts) ->
+    make_orddict(pass4(pass3(pass2(pass1(reset(make_dict(Parse),
+                                               Opts))),
+                             Opts))).
+
+%% make_orddict/1
+
+make_orddict(Dict) ->
+    dict:fold(fun mo/3,
+              orddict:from_list([{K,[]} || K <- [avp_types,
+                                                 messages,
+                                                 grouped,
+                                                 inherits,
+                                                 custom_types,
+                                                 codecs,
+                                                 avp_vendor_id,
+                                                 enum,
+                                                 define]]),
+              Dict).
+
+mo(K, Sects, Dict)
+  when is_atom(K) ->
+    orddict:store(K, make(K, Sects), Dict);
+
+mo(_, _, Dict) ->
+    Dict.
+
+make(K, [[_Line, {_, _, X}]])
+  when K == id;
+       K == name;
+       K == prefix ->
+    X;
+
+make(vendor, [[_Line, {_, _, Id}, {_, _, Name}]]) ->
+    {Id, Name};
+
+make(K, T)
+  when K == command_codes;
+       K == import_avps;
+       K == import_groups;
+       K == import_enums ->
+    T;
+
+make(K, Sects) ->
+    post(K, foldl(fun([_L|B], A) -> make(K,B,A) end,
+                  [],
+                  Sects)).
+
+post(avp_types, L) ->
+    lists:sort(L);
+
+post(K, L)
+  when K == grouped;
+       K == messages;
+       K == enum;
+       K == define ->
+    lists:reverse(L);
+
+post(_, L) ->
+    L.
+
+make(K, [{_,_,Name} | Body], Acc)
+  when K == enum;
+       K == define;
+       K == avp_vendor_id;
+       K == custom_types;
+       K == inherits;
+       K == codecs ->
+    [{Name, mk(K, Body)} | Acc];
+
+make(K, Body, Acc) ->
+    foldl(fun(T,A) -> [mk(K, T) | A] end, Acc, Body).
+
+mk(avp_types, [{_,_,Name}, {_,_,Code}, {_,_,Type}, {_,_,Flags}]) ->
+    {Name, Code, type(Type), Flags};
+
+mk(messages, [{'answer-message' = A, _}, false | Avps]) ->
+    {?L(A), -1, ['ERR', 'PXY'], [], make_body(Avps)};
+
+mk(messages, [{_,_,Name}, [{_,_,Code}, Flags, ApplId] | Avps]) ->
+    {Name,
+     Code,
+     lists:map(fun({F,_}) -> F end, Flags),
+     opt(ApplId),
+     make_body(Avps)};
+
+mk(grouped, [{_,_,Name}, [{_,_,Code}, Vid] | Avps]) ->
+    {Name, Code, opt(Vid), make_body(Avps)};
+
+mk(K, Body)
+  when K == enum;
+       K == define ->
+    lists:map(fun([{_,_,Name}, {_,_,Value}]) -> {Name, Value} end, Body);
+
+mk(K, Avps)
+  when K == avp_vendor_id;
+       K == custom_types;
+       K == inherits;
+       K == codecs ->
+    lists:map(fun({_,_,N}) -> N end, Avps).
+
+opt(false) ->
+    [];
+opt({_,_,X}) ->
+    [X].
+
+make_body(Avps) ->
+    lists:map(fun avp/1, Avps).
+
+avp([false, D, Avp]) ->
+    avp(D, Avp);
+avp([Q, D, Avp]) ->
+    {qual(Q), avp(D, Avp)}.
+
+avp(D, {'AVP', _}) ->
+    delim(D, "AVP");
+avp(D, {_, _, Name}) ->
+    delim(D, Name).
+
+delim($<, N) ->
+    {{N}};
+delim(${, N) ->
+    {N};
+delim($[, N) ->
+    [N].
+
+qual({true, {_,_,N}}) ->
+    {'*', N};
+qual({{_,_,N}, true}) ->
+    {N, '*'};
+qual({{_,_,N},{_,_,M}}) ->
+    {N, M};
+qual(true) ->
+    '*'.
+
+%% Optional reports when running verbosely.
+report(What, [F | A])
+  when is_function(F) ->
+    report(What, apply(F, A));
+report(What, Data) ->
+    report(get({?MODULE, verbose}), What, Data).
+
+report(true, Tag, Data) ->
+    io:format("##~n## ~p ~p~n", [Tag, Data]);
+report(false, _, _) ->
+    ok.
+
+%% ------------------------------------------------------------------------
+%% make_dict/1
+%%
+%% Turn a parsed dictionary into an dict.
+
+make_dict(Parse) ->
+    foldl(fun(T,A) ->
+                  report(section, T),
+                  section(T,A)
+          end,
+          dict:new(),
+          Parse).
+
+section([{T, L} | Rest], Dict)
+  when T == name;
+       T == prefix;
+       T == id;
+       T == vendor ->
+    case find(T, Dict) of
+        [] ->
+            dict:store(T, [[L | Rest]], Dict);
+        [[Line | _]] ->
+            ?RETURN(duplicate_section, [T, L, Line])
+    end;
+
+section([{T, L} | Rest], Dict)
+  when T == avp_types;
+       T == messages;
+       T == grouped;
+       T == inherits;
+       T == custom_types;
+       T == codecs;
+       T == avp_vendor_id;
+       T == enum;
+       T == define ->
+    dict:append(T, [L | Rest], Dict).
+
+%% ===========================================================================
+%% reset/2
+%%
+%% Reset sections from options.
+
+reset(Dict, Opts) ->
+    foldl([fun reset/3, Opts], Dict, [name, prefix, inherits]).
+
+reset(K, Dict, Opts) ->
+    foldl(fun opt/2, Dict, [T || {A,_} = T <- Opts, A == K]).
+
+opt({inherits = Key, "-"}, Dict) ->
+    dict:erase(Key, Dict);
+opt({inherits = Key, Mod}, Dict) ->
+    dict:append(Key, [0, {word, 0, Mod}], Dict);
+opt({Key, Val}, Dict) ->
+    dict:store(Key, [0, {word, 0, Val}], Dict);
+opt(_, Dict) ->
+    Dict.
+
+%% ===========================================================================
+%% pass1/1
+%%
+%% Explode sections into additional dictionary entries plus semantic
+%% checks.
+
+pass1(Dict) ->
+    true = no_messages_without_id(Dict),
+
+    foldl(fun(K,D) -> foldl([fun p1/3, K], D, find(K,D)) end,
+          Dict,
+          [avp_types,  %% must precede inherits, grouped, enum
+           avp_vendor_id,
+           custom_types,
+           codecs,
+           inherits,
+           grouped,
+           messages,
+           enum,
+           define]).
+
+%% Multiple sections are allowed as long as their bodies don't
+%% overlap. (Except enum/define.)
+
+p1([_Line, X | Body], Dict, K)
+  when K == avp_vendor_id;
+       K == custom_types;
+       K == codecs;
+       K == inherits ->
+    foldl([fun explode/4, X, K], Dict, Body);
+
+p1([_Line, X | Body], Dict, K)
+  when K == define;
+       K == enum ->
+    {_, L, Name} = X,
+    foldl([fun explode2/4, X, K],
+          store_new({K, Name},
+                    [L, Body],
+                    Dict,
+                    [K, Name, L],
+                    already_declared),
+          Body);
+
+p1([_Line | Body], Dict, K)
+  when K == avp_types;
+       K == grouped;
+       K == messages ->
+    foldl([fun explode/3, K], Dict, Body).
+
+no_messages_without_id(Dict) ->
+    case find(messages, Dict) of
+        [] ->
+            true;
+        [[Line | _] | _] ->
+            [] /= find(id, Dict) orelse ?RETURN(messages_without_id, [Line])
+    end.
+
+%% Note that the AVP's in avp_vendor_id, custom_types, codecs and
+%% enum can all be inherited, as can the AVP content of messages and
+%% grouped AVP's. Check that the referenced AVP's exist after
+%% importing definitions.
+
+%% explode/4
+%%
+%% {avp_vendor_id, AvpName}                 -> [Lineno, Id::integer()]
+%% {custom_types|codecs|inherits,  AvpName} -> [Lineno, Mod::string()]
+
+explode({_, Line, AvpName}, Dict, {_, _, X}, K) ->
+    true = K /= inherits orelse avp_not_local(AvpName, Line, Dict),
+
+    store_new({key(K), AvpName},
+              [Line, X],
+              Dict,
+              [AvpName, Line, K],
+              avp_already_defined).
+
+%% explode2/4
+
+%% {define, {Name, Key}} -> [Lineno, Value::integer(), enum|define]
+
+explode2([{_, Line, Key}, {_, _, Value}], Dict, {_, _, X}, K) ->
+    store_new({key(K), {X, Key}},
+              [Line, Value, K],
+              Dict,
+              [X, Key, K, Line],
+              key_already_defined).
+
+%% key/1
+%%
+%% Conflate keys that are equivalent as far as uniqueness of
+%% definition goes.
+
+key(K)
+  when K == enum;
+       K == define ->
+    define;
+key(K)
+  when K == custom_types;
+       K == codecs ->
+    custom;
+key(K) ->
+    K.
+
+%% explode/3
+
+%% {avp_types, AvpName}       -> [Line | Toks]
+%% {avp_types, {Code, IsReq}} -> [Line, AvpName]
+%%
+%% where AvpName = string()
+%%       Code    = integer()
+%%       IsReq   = boolean()
+
+explode([{_, Line, Name} | Toks], Dict0, avp_types = K) ->
+    %% Each AVP can be defined only once.
+    Dict1 = store_new({K, Name},
+                      [Line | Toks],
+                      Dict0,
+                      [Name, Line],
+                      avp_name_already_defined),
+
+    [{number, _, _Code}, {word, _, Type}, {word, _, _Flags}] = Toks,
+
+    true = avp_type_known(Type, Name, Line),
+
+    Dict1;
+
+%% {grouped, Name}            -> [Line, HeaderTok | AvpToks]
+%% {grouped, {Name, AvpName}} -> [Line, Qual, Delim]
+%%
+%% where Name  = string()
+%%       AvpName = string()
+%%       Qual  = {Q, Q} | boolean()
+%%       Q     = true | NumberTok
+%%       Delim = $< | ${ | $[
+
+explode([{_, Line, Name}, Header | Avps], Dict0, grouped = K) ->
+    Dict = store_new({K, Name},
+                     [Line, Header | Avps],
+                     Dict0,
+                     [Name, Line],
+                     group_already_defined),
+
+    [{_,_, Code}, Vid] = Header,
+    {DefLine, {_, _, Flags}} = grouped_flags(Name, Code, Dict0, Line),
+    V = lists:member($V, Flags),
+
+    false = vendor_id_mismatch(Vid, V, Name, Dict0, Line, DefLine),
+
+    explode_avps(Avps, Dict, K, Name);
+
+%% {messages, Name}            -> [Line, HeaderTok | AvpToks]
+%% {messages, {Code, IsReq}}   -> [Line, NameTok]
+%% {messages, Code}            -> [[Line, NameTok, IsReq]]
+%% {messages, {Name, Flag}}    -> [Line]
+%% {messages, {Name, AvpName}} -> [Line, Qual, Delim]
+%%
+%% where Name  = string()
+%%       Code  = integer()
+%%       IsReq = boolean()
+%%       Flag  = 'REQ' | 'PXY'
+%%       AvpName = string()
+%%       Qual  = true | {Q,Q}
+%%       Q     = true | NumberTok
+%%       Delim = $< | ${ | ${
+
+explode([{'answer-message' = A, Line}, false = H | Avps],
+        Dict0,
+        messages = K) ->
+    Name = ?L(A),
+    Dict1 = store_new({K, Name},
+                      [Line, H, Avps],
+                      Dict0,
+                      [Name, Line],
+                      message_name_already_defined),
+
+    explode_avps(Avps, Dict1, K, Name);
+
+explode([{_, Line, MsgName} = M, Header | Avps],
+        Dict0,
+        messages = K) ->
+    %% There can be at most one message with a given name.
+    Dict1 = store_new({K, MsgName},
+                      [Line, Header | Avps],
+                      Dict0,
+                      [MsgName, Line],
+                      message_name_already_defined),
+
+    [{_, _, Code}, Bits, ApplId] = Header,
+
+    %% An application id specified as part of the message definition
+    %% has to agree with @id. The former is parsed just because RFC
+    %% 3588 specifies it.
+    false = application_id_mismatch(ApplId, Dict1, MsgName),
+
+    IsReq = lists:keymember('REQ', 1, Bits),
+
+    %% For each command code, there can be at most one request and
+    %% one answer.
+    Dict2 = store_new({K, {Code, IsReq}},
+                      [Line, M],
+                      Dict1,
+                      [choose(IsReq, "Request", "Answer"), Code, Line],
+                      message_code_already_defined),
+
+    %% For each message, each flag can occur at most once.
+    Dict3 = foldl(fun({F,L},D) ->
+                          store_new({K, {MsgName, F}},
+                                    [L],
+                                    D,
+                                    [MsgName, ?L(F)],
+                                    message_has_duplicate_flag)
+                  end,
+                  Dict2,
+                  Bits),
+
+    dict:append({K, Code},
+                [Line, M, IsReq],
+                explode_avps(Avps, Dict3, K, MsgName)).
+
+%% explode_avps/4
+%%
+%% Ensure required AVP order and sane qualifiers. Can't check for AVP
+%% names until after they've been imported.
+%%
+%% RFC 3588 allows a trailing fixed while 3588bis doesn't. Parse the
+%% former.
+
+explode_avps(Avps, Dict, Key, Name) ->
+    xa("<{[<", Avps, Dict, Key, Name).
+
+xa(_, [], Dict, _, _) ->
+    Dict;
+
+xa(Ds, [[Qual, D, {'AVP', Line}] | Avps], Dict, Key, Name) ->
+    xa(Ds, [[Qual, D, {word, Line, "AVP"}] | Avps], Dict, Key, Name);
+
+xa([], [[_Qual, D, {_, Line, Name}] | _], _, _, _) ->
+    ?RETURN(invalid_avp_order, [D, Name, close(D), Line]);
+
+xa([D|_], [[{{_, Line, Min}, {_, _, Max}}, D, _] | _], _, _, _)
+  when Min > Max ->
+    ?RETURN(invalid_qualifier, [Min, Max, Line]);
+
+xa([D|_] = Ds, [[Qual, D, {_, Line, AvpName}] | Avps], Dict, Key, Name) ->
+    xa(Ds,
+       Avps,
+       store_new({Key, {Name, AvpName}},
+                 [Line, Qual, D],
+                 Dict,
+                 [Name, Line],
+                 avp_already_referenced),
+       Key,
+       Name);
+
+xa([_|Ds], Avps, Dict, Key, Name) ->
+    xa(Ds, Avps, Dict, Key, Name).
+
+close($<) -> $>;
+close(${) -> $};
+close($[) -> $].
+
+%% application_id_mismatch/3
+
+application_id_mismatch({number, Line, Id}, Dict, MsgName) ->
+    [[_, {_, L, I}]] = dict:fetch(id, Dict),
+
+    I /= Id andalso ?RETURN(message_application_id_mismatch,
+                            [MsgName, Id, Line, I, L]);
+
+application_id_mismatch(false = No, _, _) ->
+    No.
+
+%% avp_not_local/3
+
+avp_not_local(Name, Line, Dict) ->
+    A = find({avp_types, Name}, Dict),
+
+    [] == A orelse ?RETURN(inherited_avp_already_defined,
+                           [Name, Line, hd(A)]).
+
+%% avp_type_known/3
+
+avp_type_known(Type, Name, Line) ->
+    false /= type(Type)
+        orelse ?RETURN(avp_has_unknown_type, [Name, Line, Type]).
+
+%% vendor_id_mismatch/6
+
+vendor_id_mismatch({_,_,_}, false, Name, _, Line, DefLine) ->
+    ?RETURN(grouped_vendor_id_without_flag, [Name, Line, DefLine]);
+
+vendor_id_mismatch({_, _, I}, true, Name, Dict, Line, _) ->
+    case vendor_id(Name, Dict) of
+        {avp_vendor_id, L, N} ->
+            I /= N andalso
+                ?RETURN(grouped_vendor_id_mismatch, [Name, Line, I, N, L]);
+        _ ->
+            false
+    end;
+
+vendor_id_mismatch(_, _, _, _, _, _) ->
+    false.
+
+%% grouped_flags/4
+
+grouped_flags(Name, Code, Dict, Line) ->
+    case find({avp_types, Name}, Dict) of
+        [L, {_, _, Code}, {_, _, "Grouped"}, Flags] ->
+            {L, Flags};
+        [_, {_, L, C}, {_, _, "Grouped"}, _Flags] ->
+            ?RETURN(grouped_avp_code_mismatch, [Name, Line, Code, C, L]);
+        [_, _Code, {_, L, T}, _] ->
+            ?RETURN(grouped_avp_has_wrong_type, [Name, Line, T, L]);
+        [] ->
+            ?RETURN(grouped_avp_not_defined, [Name, Line])
+    end.
+
+%% vendor_id/2
+
+%% Look for a vendor id in @avp_vendor_id, then @vendor.
+vendor_id(Name, Dict) ->
+    case find({avp_vendor_id, Name}, Dict) of
+        [Line, Id] when is_integer(Id) ->
+            {avp_vendor_id, Line, Id};
+        [] ->
+            vendor(Dict)
+    end.
+
+vendor(Dict) ->
+    case find(vendor, Dict) of
+        [[_Line, {_, _, Id}, {_, _, _}]] ->
+            {vendor, Id};
+        [] ->
+            false
+    end.
+
+%% find/2
+
+find(Key, Dict) ->
+    case dict:find(Key, Dict) of
+        {ok, L} when is_list(L) ->
+            L;
+        error ->
+            []
+    end.
+
+%% store_new/5
+
+store_new(Key, Value, Dict, Args, Err) ->
+    case dict:find(Key, Dict) of
+        {ok, [L | _]} ->
+            ?RETURN(Err, Args ++ [L]);
+        error ->
+            dict:store(Key, Value, Dict)
+    end.
+
+%% type/1
+
+type("DiamIdent") ->
+    "DiameterIdentity";
+type("DiamURI") ->
+    "DiameterURI";
+type(T)
+  when T == "OctetString";
+       T == "Integer32";
+       T == "Integer64";
+       T == "Unsigned32";
+       T == "Unsigned64";
+       T == "Float32";
+       T == "Float64";
+       T == "Grouped";
+       T == "Enumerated";
+       T == "Address";
+       T == "Time";
+       T == "UTF8String";
+       T == "DiameterIdentity";
+       T == "DiameterURI";
+       T == "IPFilterRule";
+       T == "QoSFilterRule" ->
+    T;
+type(_) ->
+    false.
+
+%% ===========================================================================
+%% pass2/1
+%%
+%% More explosion, but that requires the previous pass to write its
+%% entries.
+
+pass2(Dict) ->
+    foldl(fun(K,D) -> foldl([fun p2/3, K], D, find(K,D)) end,
+          Dict,
+          [avp_types]).
+
+p2([_Line | Body], Dict, avp_types) ->
+    foldl(fun explode_avps/2, Dict, Body);
+
+p2([], Dict, _) ->
+    Dict.
+
+explode_avps([{_, Line, Name} | Toks], Dict) ->
+    [{number, _, Code}, {word, _, _Type}, {word, _, Flags}] = Toks,
+
+    true = avp_flags_valid(Flags, Name, Line),
+
+    Vid = avp_vendor_id(Flags, Name, Line, Dict),
+
+    %% An AVP is uniquely defined by its AVP code and vendor id (if any).
+    %% Ensure there are no duplicate.
+    store_new({avp_types, {Code, Vid}},
+              [Line, Name],
+              Dict,
+              [Code, Vid, Name, Line],
+              avp_code_already_defined).
+
+%% avp_flags_valid/3
+
+avp_flags_valid(Flags, Name, Line) ->
+    Bad = lists:filter(fun(C) -> not lists:member(C, "MVP") end, Flags),
+    [] == Bad
+        orelse ?RETURN(avp_has_invalid_flag, [Name, Line, hd(Bad)]),
+
+    Dup = Flags -- "MVP",
+    [] == Dup
+        orelse ?RETURN(avp_has_duplicate_flag, [Name, Line, hd(Dup)]).
+
+%% avp_vendor_id/4
+
+avp_vendor_id(Flags, Name, Line, Dict) ->
+    V = lists:member($V, Flags),
+
+    case vendor_id(Name, Dict) of
+        {avp_vendor_id, _, I} when V ->
+            I;
+        {avp_vendor_id, L, I} ->
+            ?RETURN(avp_has_vendor_id, [Name, Line, I, L]);
+        {vendor, I} when V ->
+            I;
+        false when V ->
+            ?RETURN(avp_has_no_vendor, [Name, Line]);
+        _ ->
+            false
+    end.
+
+%% ===========================================================================
+%% pass3/2
+%%
+%% Import AVPs.
+
+pass3(Dict, Opts) ->
+    import_enums(import_groups(import_avps(insert_codes(Dict), Opts))).
+
+%% insert_codes/1
+%%
+%% command_codes -> [{Code, ReqNameTok, AnsNameTok}]
+
+insert_codes(Dict) ->
+    dict:store(command_codes,
+               dict:fold(fun make_code/3, [], Dict),
+               Dict).
+
+make_code({messages, Code}, Names, Acc)
+  when is_integer(Code) ->
+    [mk_code(Code, Names) | Acc];
+make_code(_, _, Acc) ->
+    Acc.
+
+mk_code(Code, [[_, _, false] = Ans, [_, _, true] = Req]) ->
+    mk_code(Code, [Req, Ans]);
+
+mk_code(Code, [[_, {_,_,Req}, true], [_, {_,_,Ans}, false]]) ->
+    {Code, Req, Ans};
+
+mk_code(_Code, [[Line, _Name, IsReq]]) ->
+    ?RETURN(message_missing, [choose(IsReq, "Request", "Answer"),
+                              Line,
+                              choose(IsReq, "answer", "request")]).
+
+%% import_avps/2
+
+import_avps(Dict, Opts) ->
+    Import = inherit(Dict, Opts),
+    report(imported, Import),
+
+    %% pass4/1 tests that all referenced AVP's are either defined
+    %% or imported.
+
+    dict:store(import_avps,
+               lists:map(fun({M, _, As}) -> {M, [A || {_,A} <- As]} end,
+                         lists:reverse(Import)),
+               foldl(fun explode_imports/2, Dict, Import)).
+
+explode_imports({Mod, Line, Avps}, Dict) ->
+    foldl([fun xi/4, Mod, Line], Dict, Avps).
+
+xi({L, {Name, _Code, _Type, _Flags} = A}, Dict, Mod, Line) ->
+    store_new({avp_types, Name},
+              [0, Mod, Line, L, A],
+              store_new({import, Name},
+                        [Line],
+                        Dict,
+                        [Name, Line],
+                        duplicate_import),
+              [Name, Mod, Line],
+              imported_avp_already_defined).
+
+%% 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(Dict) ->
+    dict:store(import_groups, import(grouped, Dict), Dict).
+
+import_enums(Dict) ->
+    dict:store(import_enums, import(enum, Dict), Dict).
+
+import(Key, Dict) ->
+    flatmap([fun import_key/2, Key], dict:fetch(import_avps, Dict)).
+
+import_key({Mod, Avps}, Key) ->
+    As = lists:flatmap(fun(T) ->
+                               N = element(1,T),
+                               choose(lists:keymember(N, 1, Avps), [T], [])
+                       end,
+                       orddict:fetch(Key, dict(Mod))),
+    if As == [] ->
+            [];
+       true ->
+            [{Mod, As}]
+    end.
+
+%% ------------------------------------------------------------------------
+%% inherit/2
+%%
+%% Return a {Mod, Line, [{Lineno, Avp}]} list, where Mod is a module
+%% name, Line points to the corresponding @inherit and each Avp is
+%% from Mod:dict(). Lineno is 0 if the import is implicit.
+
+inherit(Dict, Options) ->
+    Path = [D || {include, D} <- Options]
+        ++ [".", code:lib_dir(diameter, ebin)],
+    foldl([fun find_avps/3, Path], [], find(inherits, Dict)).
+%% Note that the module order of the returned lists is reversed
+%% relative to @inherits.
+
+find_avps([Line, {_,_,M} | Names], Acc, Path) ->
+    Mod = ?A(M),
+    report(inherit_from, Mod),
+    Avps = avps_from_beam(find_beam(Mod, Path), Mod),  %% could be empty
+    case find_avps(Names, Avps) of
+        {_, [{_, L, N} | _]} ->
+            ?RETURN(requested_avp_not_found, [Mod, Line, N, L]);
+        {Found, []} ->
+            [{Mod, Line, lists:sort(Found)} | Acc]
+    end.
+
+%% Import everything not defined locally ...
+find_avps([], Avps) ->
+    {[{0, A} || A <- Avps], []};
+
+%% ... or specified AVPs.
+find_avps(Names, Avps) ->
+    foldl(fun fa/2, {[], Names}, Avps).
+
+fa({Name, _Code, _Type, _Flags} = A, {Found, Not} = Acc) ->
+    case lists:keyfind(Name, 3, Not) of
+        {_, Line, Name} ->
+            {[{Line, A} | Found], lists:keydelete(Name, 3, Not)};
+        false ->
+            Acc
+    end.
+
+%% find_beam/2
+
+find_beam(Mod, Dirs)
+  when is_atom(Mod) ->
+    find_beam(atom_to_list(Mod), Dirs);
+find_beam(Mod, Dirs) ->
+    Beam = Mod ++ code:objfile_extension(),
+    case try_path(Dirs, Beam) of
+        {value, Path} ->
+            Path;
+        false ->
+            ?RETURN(beam_not_on_path, [Mod])
+    end.
+
+try_path([D|Ds], Fname) ->
+    Path = filename:join(D, Fname),
+    case file:read_file_info(Path) of
+        {ok, _} ->
+            {value, Path};
+        _ ->
+            try_path(Ds, Fname)
+    end;
+try_path([], _) ->
+    false.
+
+%% avps_from_beam/2
+
+avps_from_beam(Path, Mod) ->
+    report(beam, Path),
+    ok = load_module(code:is_loaded(Mod), Mod, Path),
+    orddict:fetch(avp_types, dict(Mod)).
+
+load_module(false, Mod, Path) ->
+    R = filename:rootname(Path, code:objfile_extension()),
+    {module, Mod} = code:load_abs(R),
+    ok;
+load_module({file, _}, _, _) ->
+    ok.
+
+dict(Mod) ->
+    try Mod:dict() of
+        [?VERSION | Dict] ->
+            Dict;
+        _ ->
+            ?RETURN(recompile, [Mod])
+    catch
+        error:_ ->
+            ?RETURN(no_dict, [Mod])
+    end.
+
+%% ===========================================================================
+%% pass4/1
+%%
+%% Sanity checks.
+
+pass4(Dict) ->
+    dict:fold(fun(K, V, _) -> p4(K, V, Dict) end, ok, Dict),
+    Dict.
+
+%% Ensure enum AVP's have type Enumerated.
+p4({enum, Name}, [Line | _], Dict)
+  when is_list(Name) ->
+    true = is_enumerated_avp(Name, Dict, Line);
+
+%% Ensure all referenced AVP's are either defined locally or imported.
+p4({K, {Name, AvpName}}, [Line | _], Dict)
+  when (K == grouped orelse K == messages),
+       is_list(Name),
+       is_list(AvpName),
+       AvpName /= "AVP" ->
+    true = avp_is_defined(AvpName, Dict, Line);
+
+%% Ditto.
+p4({K, AvpName}, [Line | _], Dict)
+  when K == avp_vendor_id;
+       K == custom_types;
+       K == codecs ->
+    true = avp_is_defined(AvpName, Dict, Line);
+
+p4(_, _, _) ->
+    ok.
+
+%% has_enumerated_type/3
+
+is_enumerated_avp(Name, Dict, Line) ->
+    case find({avp_types, Name}, Dict) of
+        [_Line, _Code, {_, _, "Enumerated"}, _Flags] ->   %% local
+            true;
+        [_Line, _Code, {_, L, T}, _] ->
+            ?RETURN(enumerated_avp_has_wrong_local_type,
+                    [Name, Line, T, L]);
+        [0, _, _, _, {_Name, _Code, "Enumerated", _Flags}] ->   %% inherited
+            true;
+        [0, Mod, LM, LA, {_Name, _Code, Type, _Flags}] ->
+            ?RETURN(enumerated_avp_has_wrong_inherited_type,
+                    [Name, Line, Type, Mod, choose(0 == LA, LM, LA)]);
+        [] ->
+            ?RETURN(enumerated_avp_not_defined, [Name, Line])
+    end.
+
+avp_is_defined(Name, Dict, Line) ->
+    case find({avp_types, Name}, Dict) of
+        [_Line, _Code, _Type, _Flags] ->   %% local
+            true;
+        [0, _, _, _, {Name, _Code, _Type, _Flags}] ->  %% inherited
+            true;
+        [] ->
+            ?RETURN(avp_not_defined, [Name, Line])
+    end.
+
+%% ===========================================================================
+
+choose(true, X, _)  -> X;
+choose(false, _, X) -> X.
+
+foldl(F, Acc, List) ->
+    lists:foldl(fun(T,A) -> eval([F,T,A]) end, Acc, List).
+
+flatmap(F, List) ->
+    lists:flatmap(fun(T) -> eval([F,T]) end, List).
+
+eval([[F|X] | A]) ->
+    eval([F | A ++ X]);
+eval([F|A]) ->
+    apply(F,A).