Add field 'mtlhash' to the database, for get-proof-by-hash.

Also, in db:
Add field 'mtlhash' to record 'plop'. Rename 'hash' -> 'entryhash'.
Add leaf_hash(), calculating a leaf hash from data.
Fix a bug where print_tree() print half a byte of the hashes.
Rename tree_hash() -> root().

Closes CATLFISH-3.

1 files changed, 27 insertions, 16 deletions

diff --git a/src/db.erl b/src/db.erl
index 8f398cb..25cfc5e 100644
--- a/src/db.erl
+++ b/src/db.erl
@@ -7,7 +7,7 @@
 %% API.
 -export([start_link/0, stop/0]).
 -export([init_db/0, init_db/1, init_tables/0, init_tables/1]).
--export([add/1, find/1, get_by_index/2, get_by_index_sorted/2, size/0]).
+-export([add/1, find/2, get_by_index/2, get_by_index_sorted/2, size/0]).
 %% API for testing.
 -export([dump/1, destroy_tables/0, info_tables/0, dump_to_file/1]).
 %% gen_server callbacks.
@@ -48,7 +48,8 @@ init_tables(Nodes) ->
                              {disc_only_copies, DiscOnlyCopies},
                              {attributes, record_info(fields, plop)},
                              {majority, true}]),
-    {atomic, ok} = mnesia:add_table_index(plop, hash).
+    {atomic, ok} = mnesia:add_table_index(plop, entryhash),
+    {atomic, ok} = mnesia:add_table_index(plop, mtlhash).
 
 destroy_tables() ->
     mnesia:delete_table(plop).
@@ -74,8 +75,12 @@ stop() ->
 add(Entry) ->
     gen_server:call(?MODULE, {add, Entry}).
 
-find(Hash) ->
-    gen_server:call(?MODULE, {find, Hash}).
+%% @doc Find entry with entryhash=Hash.
+find(entryhash, Hash) ->
+    gen_server:call(?MODULE, {find, entryhash, Hash});
+%% @doc Find entry with mtlhash=Hash.
+find(mtlhash, Hash) ->
+    gen_server:call(?MODULE, {find, mtlhash, Hash}).
 
 dump(Table) ->
     gen_server:call(?MODULE, {dump, Table}).
@@ -122,17 +127,14 @@ handle_call({dump, Table}, _From, State) ->
         end,
     Res = mnesia:transaction(F),
     {reply, Res, State};
-handle_call({find, Hash}, _From, State) ->
-    F = fun() ->
-                mnesia:index_read(plop, Hash, #plop.hash)
-        end,
-    {atomic, Result} = mnesia:transaction(F),
-    Record = case length(Result) of
-                 0 -> [];
-                 1 -> hd(Result);
-                 _ -> duplicate_hash_in_db      % FIXME: log an error
-             end,
-    {reply, Record, State};
+handle_call({find, entryhash, Hash}, _From, State) ->
+    {reply,
+     find_entry(fun() -> mnesia:index_read(plop, Hash, #plop.entryhash) end),
+     State};
+handle_call({find, mtlhash, Hash}, _From, State) ->
+    {reply,
+     find_entry(fun() -> mnesia:index_read(plop, Hash, #plop.mtlhash) end),
+     State};
 handle_call({get_by_index, {Start, End}}, _From, State) ->
     Res = [X || [_, X] <- select_index(Start, End)],
     {reply, Res, State};
@@ -146,10 +148,19 @@ handle_call({get_by_index_sorted, {Start, End}}, _From, State) ->
 
 select_index(Start, End) ->
     F = fun() ->
-                MatchHead = {plop, '$1', '_', '$2', '_'},
+                %% Get index and mtl.
+                MatchHead = {plop, '$1', '_', '_', '$2', '_'},
                 Guard = [{'>=', '$1', Start}, {'=<', '$1', End}],
                 Result = ['$$'],
                 mnesia:select(plop, [{MatchHead, Guard, Result}])
         end,
     {atomic, Res} = mnesia:transaction(F),
     Res.
+
+find_entry(Fun) ->
+    {atomic, Result} = mnesia:transaction(Fun),
+    case length(Result) of
+        0 -> [];
+        1 -> hd(Result);
+        _ -> duplicate_hash_in_db               % FIXME: log an error?
+    end.