1 files changed, 89 insertions, 27 deletions

diff --git a/lib/asn1/src/asn1_db.erl b/lib/asn1/src/asn1_db.erl
index 869b36ddbd..48d9dd16d7 100644
--- a/lib/asn1/src/asn1_db.erl
+++ b/lib/asn1/src/asn1_db.erl
@@ -19,25 +19,37 @@
 %%
 -module(asn1_db).
 
--export([dbstart/1,dbnew/1,dbsave/2,dbput/3,dbget/2]).
+-export([dbstart/1,dbnew/2,dbload/1,dbload/3,dbsave/2,dbput/3,dbget/2]).
 -export([dbstop/0]).
 
 -record(state, {parent, monitor, includes, table}).
 
 %% Interface
-dbstart(Includes) ->
+dbstart(Includes0) ->
+    Includes = case Includes0 of
+		   [] -> ["."];
+		   [_|_] -> Includes0
+	       end,
     Parent = self(),
     undefined = get(?MODULE),			%Assertion.
     put(?MODULE, spawn_link(fun() -> init(Parent, Includes) end)),
     ok.
 
-dbnew(Module)              -> req({new, Module}).
+dbload(Module, Erule, Mtime) ->
+    req({load, Module, Erule, Mtime}).
+
+dbload(Module) ->
+    req({load, Module, any, {{0,0,0},{0,0,0}}}).
+
+dbnew(Module, Erule)       -> req({new, Module, Erule}).
 dbsave(OutFile, Module)    -> cast({save, OutFile, Module}).
 dbput(Module, K, V)        -> cast({set, Module, K, V}).
 dbget(Module, K)           -> req({get, Module, K}).
 dbstop()                   -> Resp = req(stop), erase(?MODULE), Resp.
 
 %% Internal functions
+-define(MAGIC_KEY, '__version_and_erule__').
+
 req(Request) ->
     DbPid = get(?MODULE),
     Ref = erlang:monitor(process,DbPid),
@@ -71,47 +83,57 @@ loop(#state{parent = Parent, monitor = MRef, table = Table,
             ets:insert(Modtab, {K2, V}),
             loop(State);
         {From, {get, Mod, K2}} ->
-            Result = case ets:lookup(Table, Mod) of
-                         []            -> opentab(Table, Mod, Includes);
-                         [{_, Modtab}] -> {ok, Modtab}
-                     end,
-            case Result of
-                {ok, Newtab} -> reply(From, lookup(Newtab, K2));
-                _Error       -> reply(From, undefined)
+	    %% XXX If there is no information for Mod, get_table/3
+	    %% will attempt to load information from an .asn1db
+	    %% file, without comparing its timestamp against the
+	    %% source file. This is known to happen when check_*
+	    %% functions for DER are generated, but it could possibly
+	    %% happen in other circumstances. Ideally, this issue should
+	    %% be rectified in some way, perhaps by ensuring that
+	    %% the module has been loaded (using dbload/4) prior
+	    %% to calling dbget/2.
+            case get_table(Table, Mod, Includes) of
+                {ok,Tab} -> reply(From, lookup(Tab, K2));
+                error -> reply(From, undefined)
             end,
             loop(State);
         {save, OutFile, Mod} ->
             [{_,Mtab}] = ets:lookup(Table, Mod),
             ok = ets:tab2file(Mtab, OutFile),
             loop(State);
-        {From, {new, Mod}} ->
+        {From, {new, Mod, Erule}} ->
             [] = ets:lookup(Table, Mod),	%Assertion.
             ModTableId = ets:new(list_to_atom(lists:concat(["asn1_",Mod])), []),
             ets:insert(Table, {Mod, ModTableId}),
+	    ets:insert(ModTableId, {?MAGIC_KEY, info(Erule)}),
             reply(From, ok),
             loop(State);
+	{From, {load, Mod, Erule, Mtime}} ->
+	    case ets:member(Table, Mod) of
+		true ->
+		    reply(From, ok);
+		false ->
+		    case load_table(Mod, Erule, Mtime, Includes) of
+			{ok, ModTableId} ->
+			    ets:insert(Table, {Mod, ModTableId}),
+			    reply(From, ok);
+			error ->
+			    reply(From, error)
+		    end
+	    end,
+	    loop(State);
         {From, stop} ->
             reply(From, stopped); %% Nothing to store
         {'DOWN', MRef, process, Parent, Reason} ->
             exit(Reason)
     end.
 
-opentab(Tab, Mod, []) ->
-    opentab(Tab, Mod, ["."]);
-opentab(Tab, Mod, Includes) ->
-    Base = lists:concat([Mod, ".asn1db"]),
-    opentab2(Tab, Base, Mod, Includes, ok).
-
-opentab2(_Tab, _Base, _Mod, [], Error) ->
-    Error;
-opentab2(Tab, Base, Mod, [Ih|It], _Error) ->
-    File = filename:join(Ih, Base),
-    case ets:file2tab(File) of
-        {ok, Modtab} ->
-            ets:insert(Tab, {Mod, Modtab}),
-            {ok, Modtab};
-        NewErr ->
-            opentab2(Tab, Base, Mod, It, NewErr)
+get_table(Table, Mod, Includes) ->
+    case ets:lookup(Table, Mod) of
+	[{Mod,Tab}] ->
+	    {ok,Tab};
+	[] ->
+	    load_table(Mod, any, {{0,0,0},{0,0,0}}, Includes)
     end.
 
 lookup(Tab, K) ->
@@ -119,3 +141,43 @@ lookup(Tab, K) ->
         []      -> undefined;
         [{K,V}] -> V
     end.
+
+info(Erule) ->
+    {asn1ct:vsn(),Erule}.
+
+load_table(Mod, Erule, Mtime, Includes) ->
+    Base = lists:concat([Mod, ".asn1db"]),
+    case path_find(Includes, Mtime, Base) of
+	error ->
+	    error;
+	{ok,ModTab} when Erule =:= any ->
+	    {ok,ModTab};
+	{ok,ModTab} ->
+	    Vsn = asn1ct:vsn(),
+	    case ets:lookup(ModTab, ?MAGIC_KEY) of
+		[{_,{Vsn,Erule}}] ->
+		    %% Correct version and encoding rule.
+		    {ok,ModTab};
+		_ ->
+		    %% Missing key or wrong version/encoding rule.
+		    ets:delete(ModTab),
+		    error
+	    end
+    end.
+
+path_find([H|T], Mtime, Base) ->
+    File = filename:join(H, Base),
+    case filelib:last_modified(File) of
+	0 ->
+	    path_find(T, Mtime, Base);
+	DbMtime when DbMtime >= Mtime ->
+	    case ets:file2tab(File) of
+		{ok,_}=Ret ->
+		    Ret;
+		_ ->
+		    path_find(T, Mtime, Base)
+	    end;
+	_ ->
+	    path_find(T, Mtime, Base)
+    end;
+path_find([], _, _) -> error.