Fix a bug in Dets concerning repair of almost full tables

A Dets table with sufficiently large buckets could not always be repaired.
(Reported by Gordon Guthrie.)

The format of Dets files has been modified. When downgrading tables
created with the new system will be repaired. Otherwise the
modification should not be noticeable.

1 files changed, 25 insertions, 32 deletions

diff --git a/lib/stdlib/src/dets.erl b/lib/stdlib/src/dets.erl
index 7ed9c4b695..c0f9ce34b0 100644
--- a/lib/stdlib/src/dets.erl
+++ b/lib/stdlib/src/dets.erl
@@ -1754,17 +1754,6 @@ system_code_change(State, _Module, _OldVsn, _Extra) ->
 %%% Internal functions
 %%%----------------------------------------------------------------------
 
-constants(FH, FileName) ->
-    Version = FH#fileheader.version,
-    if 
-        Version =< 8 ->
-            dets_v8:constants();
-        Version =:= 9 ->
-            dets_v9:constants();
-        true ->
-            throw({error, {not_a_dets_file, FileName}})
-    end.
-
 %% -> {ok, Fd, fileheader()} | throw(Error)
 read_file_header(FileName, Access, RamFile) ->
     BF = if
@@ -1842,7 +1831,11 @@ do_bchunk_init(Head, Tab) ->
 		    {H2, {error, old_version}};
 		Parms ->
                     L = dets_utils:all_allocated(H2),
-                    C0 = #dets_cont{no_objs = default, bin = <<>>, alloc = L},
+                    Bin = if
+                              L =:= <<>> -> eof;
+                              true -> <<>>
+                          end,
+                    C0 = #dets_cont{no_objs = default, bin = Bin, alloc = L},
 		    BinParms = term_to_binary(Parms),
 		    {H2, {C0#dets_cont{tab = Tab, proc = self(),what = bchunk},
                           [BinParms]}}
@@ -2478,9 +2471,7 @@ fopen2(Fname, Tab) ->
             Do = case Mod:check_file_header(FH, Fd) of
                      {ok, Head1, ExtraInfo} ->
                          Head2 = Head1#head{filename = Fname},
-                         try Mod:init_freelist(Head2, ExtraInfo) of
-                             Ftab ->
-                                 {ok, Head1#head{freelists = Ftab}}
+                         try {ok, Mod:init_freelist(Head2, ExtraInfo)}
                          catch
                              throw:_ ->
                                  {repair, " has bad free lists, repairing ..."}
@@ -2574,9 +2565,7 @@ fopen_existing_file(Tab, OpenArgs) ->
     Do = case Wh of
              {Tag, Hd, Extra} when Tag =:= final; Tag =:= compact ->
                  Hd1 = Hd#head{filename = Fname},
-                 try Mod:init_freelist(Hd1, Extra) of
-                     Ftab ->
-                         {Tag, Hd#head{freelists = Ftab}}
+                 try {Tag, Mod:init_freelist(Hd1, Extra)}
                  catch
                      throw:_ ->
                          {repair, " has bad free lists, repairing ..."}
@@ -3164,8 +3153,12 @@ init_scan(Head, NoObjs) ->
     check_safe_fixtable(Head),
     FreeLists = dets_utils:get_freelists(Head),
     Base = Head#head.base,
-    {From, To} = dets_utils:find_next_allocated(FreeLists, Base, Base),
-    #dets_cont{no_objs = NoObjs, bin = <<>>, alloc = {From, To, <<>>}}.
+    case dets_utils:find_next_allocated(FreeLists, Base, Base) of
+        {From, To} ->
+            #dets_cont{no_objs = NoObjs, bin = <<>>, alloc = {From,To,<<>>}};
+        none ->
+            #dets_cont{no_objs = NoObjs, bin = eof, alloc = <<>>}
+    end.
 
 check_safe_fixtable(Head) ->
     case (Head#head.fixed =:= false) andalso 
@@ -3266,18 +3259,18 @@ view(FileName) ->
     case catch read_file_header(FileName, read, false) of
         {ok, Fd, FH} ->
 	    Mod = FH#fileheader.mod,
-            try
-                case Mod:check_file_header(FH, Fd) of
-                    {ok, H0, ExtraInfo} ->
-                        Ftab = Mod:init_freelist(H0, ExtraInfo),
-                        {_Bump, Base} = constants(FH, FileName),
-                        H = H0#head{freelists=Ftab, base = Base},
-                        v_free_list(H),
-                        Mod:v_segments(H),
-                        ok;
-                    X ->
-                        X
-                end
+            try Mod:check_file_header(FH, Fd) of
+                {ok, H0, ExtraInfo} ->
+                    Mod = FH#fileheader.mod,
+                    case Mod:check_file_header(FH, Fd) of
+                        {ok, H0, ExtraInfo} ->
+                            H = Mod:init_freelist(H0, ExtraInfo),
+                            v_free_list(H),
+                            Mod:v_segments(H),
+                            ok;
+                        X ->
+                            X
+                    end
             after file:close(Fd)
             end;
 	X ->