src/machi_merkle_tree.erl

@@ -0,0 +1,203 @@
+%% -------------------------------------------------------------------
+%%
+%% Copyright (c) 2007-2015 Basho Technologies, Inc.  All Rights Reserved.
+%%
+%% This file is provided to you under the Apache License,
+%% Version 2.0 (the "License"); you may not use this file
+%% except in compliance with the License.  You may obtain
+%% a copy of the License at
+%%
+%%   http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing,
+%% software distributed under the License is distributed on an
+%% "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+%% KIND, either express or implied.  See the License for the
+%% specific language governing permissions and limitations
+%% under the License.
+%%
+%% -------------------------------------------------------------------
+
+%% @doc Creates a Merkle tree per file based on the checksum data for
+%% a given data file.
+%%
+%% Has selectable backend, chosen at open.
+%%
+%% The default 'merklet' implementation uses the `merklet' library.  Keys are
+%% encoded as `<<Offset:64, Size:32>>' values encoded as `<<Tag:8, Csum/binary>>'
+%% *or* as `<<0>>' for unwritten bytes, or `<<1>>' for trimmed bytes.
+%%
+%% The `naive' implementation representation is:
+%%
+%% `<<Length:64, Offset:32, 0>>' for unwritten bytes
+%% `<<Length:64, Offset:32, 1>>' for trimmed bytes
+%% `<<Length:64, Offset:32, Csum/binary>>' for written bytes
+%%
+%% The tree feeds these leaf nodes into hashes representing chunks of a minimum
+%% size of at least 1024 KB (1 MB), but if the file size is larger, we will try
+%% to get about 100 chunks for called "Level 1." We aim for around 10 hashes at
+%% level 2, and then 2 hashes level 3 and finally the root.
+
+-module(machi_merkle_tree).
+
+-include("machi.hrl").
+
+-export([
+    open/2,
+    open/3,
+    tree/1,
+    filename/1,
+    diff/2
+]).
+
+
+-record(naive, {
+          chunk_size = 1048576   :: pos_integer(), %% default 1 MB
+          recalc = true          :: boolean(),
+          root                   :: 'undefined' | binary(),
+          lvl1 = []              :: [ binary() ],
+          lvl2 = []              :: [ binary() ],
+          lvl3 = []              :: [ binary() ],
+          leaves = []            :: [ { Offset :: pos_integer(),
+                                        Size :: pos_integer(),
+                                        Csum :: binary()} ]
+         }).
+
+-record(mt, {
+          filename               :: string(),
+          tree                   :: #naive{}|merklet:tree(),
+          backend = 'merklet'    :: 'naive'|'merklet'
+         }).
+
+-define(TRIMMED, <<1>>).
+-define(UNWRITTEN, <<0>>).
+-define(ENCODE(Offset, Size), <<Offset:64/unsigned-big, Size:32/unsigned-big>>).
+-define(NAIVE_ENCODE(Offset, Size, Data), <<Offset:64/unsigned-big, Size:32/unsigned-big, Data/binary>>).
+
+-define(NEW_MERKLET, undefined).
+-define(TIMEOUT, (10*1000)).
+
+-define(MINIMUM_CHUNK, 1048576). %% 1024 * 1024
+-define(LEVEL_SIZE, 10).
+-define(H, sha).
+
+%% public API
+
+open(Filename, DataDir) ->
+    open(Filename, DataDir, merklet).
+
+open(Filename, DataDir, Type) ->
+    Tree = load_filename(Filename, DataDir, Type),
+    {ok, #mt{ filename = Filename, tree = Tree, backend = Type}}.
+
+tree(#mt{ tree = T, backend = merklet }) -> T;
+tree(#mt{ tree = T, backend = naive }) ->
+    case T#naive.recalc of
+         true -> build_tree(T);
+        false -> T
+    end.
+
+filename(#mt{ filename = F }) -> F.
+
+diff(#mt{backend = naive, tree = T1}, #mt{backend = naive, tree = T2}) ->
+    case T1#naive.root == T2#naive.root of
+        true -> same;
+        false -> different %% TODO: implement diff
+    end;
+diff(#mt{backend = merklet, tree = T1}, #mt{backend = merklet, tree = T2}) ->
+    case merklet:diff(T1, T2) of
+        [] -> same;
+        Diff -> Diff
+    end;
+diff(_, _) -> error(badarg).
+
+%% private
+
+% @private
+load_filename(Filename, DataDir, merklet) ->
+    {_Last, M} = do_load(Filename, DataDir, fun insert_csum/2, ?NEW_MERKLET),
+    M;
+load_filename(Filename, DataDir, naive) ->
+    {Last, M} = do_load(Filename, DataDir, fun insert_csum_naive/2, []),
+    ChunkSize = max(?MINIMUM_CHUNK, Last div 100),
+    T = #naive{ leaves = lists:reverse(M), chunk_size = ChunkSize, recalc = true },
+    build_tree(T).
+
+do_load(Filename, DataDir, FoldFun, AccInit) ->
+    CsumFile = machi_util:make_checksum_filename(DataDir, Filename),
+    {ok, T} = machi_csum_table:open(CsumFile, []),
+    Acc = machi_csum_table:foldl_chunks(FoldFun, {0, AccInit}, T),
+    ok = machi_csum_table:close(T),
+    Acc.
+
+% @private
+insert_csum({Last, Size, _Csum}=In, {Last, MT}) ->
+    %% no gap here, insert a record
+    {Last+Size, update_merkle_tree(In, MT)};
+insert_csum({Offset, Size, _Csum}=In, {Last, MT}) ->
+    %% gap here, insert unwritten record 
+    %% *AND* insert written record
+    Hole = Offset - Last,
+    MT0 = update_merkle_tree({Last, Hole, unwritten}, MT),
+    {Offset+Size, update_merkle_tree(In, MT0)}.
+
+insert_csum_naive({Last, Size, _Csum}=In, {Last, MT}) ->
+    %% no gap
+    {Last+Size, update_acc(In, MT)};
+insert_csum_naive({Offset, Size, _Csum}=In, {Last, MT}) ->
+    Hole = Offset - Last,
+    MT0 = update_acc({Last, Hole, unwritten}, MT),
+    {Offset+Size, update_acc(In, MT0)}.
+
+% @private
+update_merkle_tree({Offset, Size, unwritten}, MT) ->
+    merklet:insert({?ENCODE(Offset, Size), ?UNWRITTEN}, MT);
+update_merkle_tree({Offset, Size, trimmed}, MT) ->
+    merklet:insert({?ENCODE(Offset, Size), ?TRIMMED}, MT);
+update_merkle_tree({Offset, Size, Csum}, MT) ->
+    merklet:insert({?ENCODE(Offset, Size), Csum}, MT).
+
+update_acc({Offset, Size, unwritten}, MT) ->
+    [ {Offset, Size, ?NAIVE_ENCODE(Offset, Size, ?UNWRITTEN)} | MT ];
+update_acc({Offset, Size, trimmed}, MT) ->
+    [ {Offset, Size, ?NAIVE_ENCODE(Offset, Size, ?TRIMMED)} | MT ];
+update_acc({Offset, Size, Csum}, MT) ->
+    [ {Offset, Size, ?NAIVE_ENCODE(Offset, Size, Csum)} | MT ].
+
+build_tree(MT = #naive{ leaves = L, chunk_size = ChunkSize }) ->
+    lager:debug("Leaves: ~p~n", [L]),
+    Lvl1s = build_level_1(ChunkSize, L, 1, [ crypto:hash_init(?H) ]),
+    lager:debug("Lvl1: ~p~n", [Lvl1s]),
+    Mod2 = length(Lvl1s) div ?LEVEL_SIZE,
+    Lvl2s = build_int_level(Mod2, Lvl1s, 1, [ crypto:hash_init(?H) ]),
+    lager:debug("Lvl2: ~p~n", [Lvl2s]),
+    Mod3 = length(Lvl2s) div 2,
+    Lvl3s = build_int_level(Mod3, Lvl2s, 1, [ crypto:hash_init(?H) ]),
+    lager:debug("Lvl3: ~p~n", [Lvl3s]),
+    Root = build_root(Lvl3s, crypto:hash_init(?H)),
+    lager:debug("Root: ~p~n", [Root]),
+    MT#naive{ root = Root, lvl1 = Lvl1s, lvl2 = Lvl2s, lvl3 = Lvl3s, recalc = false }.
+
+build_root([], Ctx) ->
+    crypto:hash_final(Ctx);
+build_root([H|T], Ctx) ->
+    build_root(T, crypto:hash_update(Ctx, H)).
+
+build_int_level(_Mod, [], _Cnt, [ Ctx | Rest ]) ->
+    lists:reverse( [ crypto:hash_final(Ctx) | Rest ] );
+build_int_level(Mod, [H|T], Cnt, [ Ctx | Rest ]) when Cnt rem Mod == 0 ->
+    NewCtx = crypto:hash_init(?H),
+    build_int_level(Mod, T, Cnt + 1, [ crypto:hash_update(NewCtx, H), crypto:hash_final(Ctx) | Rest ]);
+build_int_level(Mod, [H|T], Cnt, [ Ctx | Rest ]) ->
+    build_int_level(Mod, T, Cnt+1, [ crypto:hash_update(Ctx, H) | Rest ]).
+
+build_level_1(_Size, [], _Multiple, [ Ctx | Rest ]) ->
+    lists:reverse([ crypto:hash_final(Ctx) | Rest ]);
+build_level_1(Size, [{Pos, Len, Hash}|T], Multiple, [ Ctx | Rest ])
+                                    when ( Pos + Len ) > ( Size * Multiple ) ->
+    NewCtx = crypto:hash_init(?H),
+    build_level_1(Size, T, Multiple+1,
+                  [ crypto:hash_update(NewCtx, Hash), crypto:hash_final(Ctx) | Rest ]);
+build_level_1(Size, [{Pos, Len, Hash}|T], Multiple, [ Ctx | Rest ])
+                                    when ( Pos + Len ) =< ( Size * Multiple ) ->
+    build_level_1(Size, T, Multiple, [ crypto:hash_update(Ctx, Hash) | Rest ]).

src/machi_merkle_tree_mgr.erl

@@ -1,208 +0,0 @@
-%% -------------------------------------------------------------------
-%%
-%% Copyright (c) 2007-2015 Basho Technologies, Inc.  All Rights Reserved.
-%%
-%% This file is provided to you under the Apache License,
-%% Version 2.0 (the "License"); you may not use this file
-%% except in compliance with the License.  You may obtain
-%% a copy of the License at
-%%
-%%   http://www.apache.org/licenses/LICENSE-2.0
-%%
-%% Unless required by applicable law or agreed to in writing,
-%% software distributed under the License is distributed on an
-%% "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-%% KIND, either express or implied.  See the License for the
-%% specific language governing permissions and limitations
-%% under the License.
-%%
-%% -------------------------------------------------------------------
-
-%% @doc This manager maintains a Merkle tree per file per FLU as implemented
-%% by the `merklet' library.  Keys are encoded as `<<Offset:64, Size:32>>'
-%% values encoded as `<<Tag:8, Csum/binary>>' *or* as <<0>> for unwritten
-%% bytes, or <<1>> for trimmed bytes.
-
--module(machi_merkle_tree_mgr).
--behaviour(gen_server).
-
--include("machi.hrl").
-
--export([
-    child_spec/3,
-    start_link/3,
-    initialize/2,
-    update/5,
-    fetch/2
-]).
-
-%% gen_server callbacks
--export([
-    init/1,
-    handle_call/3,
-    handle_cast/2,
-    handle_info/2,
-    terminate/2,
-    code_change/3
-]).
-
--record(state, {
-          fluname :: atom(),
-          datadir :: string(),
-          tid     :: ets:tid()
-         }).
-
--record(mt, {
-          filename               :: string(),
-          tree                   :: merklet:tree()
-         }).
-
--define(TRIMMED, <<1>>).
--define(UNWRITTEN, <<0>>).
--define(ENCODE(Offset, Size), <<Offset:64/unsigned-big, Size:32/unsigned-big>>).
-
--define(NEW_MERKLET, undefined).
--define(TIMEOUT, (10*1000)).
-
-%% public API
-
-child_spec(FluName, DataDir, Options) ->
-    Name = make_merkle_tree_mgr_name(FluName),
-    {Name, 
-        {?MODULE, start_link, [FluName, DataDir, Options]},
-        permanent, 5000, worker, [?MODULE]}.
-
-start_link(FluName, DataDir, Options) ->
-    gen_server:start_link({local, make_merkle_tree_mgr_name(FluName)},
-                          ?MODULE,
-                          {FluName, DataDir, Options},
-                          []).
-
--spec initialize(  FluName :: atom(),
-                  Filename :: string() ) -> ok.
-%% @doc A heads-up hint to the manager that it ought to compute a merkle
-%% tree for the given file (if it hasn't already).
-initialize(FluName, Filename) ->
-    gen_server:cast(make_merkle_tree_mgr_name(FluName), 
-                    {initialize, Filename}).
-
--spec update(  FluName :: atom(),
-              Filename :: string(),
-                Offset :: non_neg_integer(),
-                Length :: pos_integer(),
-                  Csum :: binary() ) -> ok.
-%% @doc A new leaf node ought to be added file the given filename,
-%% with the particular information.
-update(FluName, Filename, Offset, Length, Csum) ->
-    gen_server:cast(make_merkle_tree_mgr_name(FluName), 
-                    {update, Filename, Offset, Length, Csum}).
-
--spec fetch ( FluName :: atom(),
-             Filename :: string() ) -> {ok, 'undefined'|merklet:tree()}.
-%% @doc Returns the merkle tree for the given filename.
-fetch(FluName, Filename) ->
-    gen_server:call(make_merkle_tree_mgr_name(FluName),
-                    {fetch, Filename}, ?TIMEOUT).
-
-%% gen_server callbacks
-init({FluName, DataDir, Options}) ->
-    Tid = ets:new(make_merkle_tree_mgr_name(FluName), [{keypos, 2}, {read_concurrency, true}]),
-    case proplists:get_value(no_load, Options, false) of
-        true ->
-            ok;
-        false ->
-            handle_load(Tid, DataDir)
-    end,
-    {ok, #state{fluname=FluName, datadir=DataDir, tid = Tid}}.
-
-handle_call({fetch, Filename}, _From, S = #state{ tid = Tid }) ->
-    Res = handle_fetch(Tid, Filename),
-    {reply, {ok, Res}, S};
-handle_call(Req, _From, State) ->
-    lager:warning("Unknown call: ~p", [Req]),
-    {reply, whoaaaaaaaaaaaa, State}.
-
-handle_cast({initialize, Filename}, S = #state{ datadir = D, tid = Tid }) ->
-    load_filename(Tid, D, Filename),
-    {noreply, S};
-
-handle_cast({update, Filename, Offset, Length, Csum}, S = #state{ tid = Tid }) ->
-    %% XXX FIXME: Not sure about the correctness of this
-    insert(Tid, Filename, {Offset, Length, Csum}),
-    {noreply, S};
-
-handle_cast(Cast, State) ->
-    lager:warning("Unknown cast: ~p", [Cast]),
-    {noreply, State}.
-
-handle_info(Req, State) ->
-    lager:warning("Unknown info message: ~p", [Req]),
-    {noreply, State}.
-
-terminate(Reason, #state{fluname = F}) ->
-    lager:debug("Shutting down merkle tree manager for FLU ~p because ~p", 
-                [F, Reason]),
-    ok.
-
-code_change(_OldVsn, State, _Extra) ->
-    {ok, State}.
-
-%% private
-
-make_merkle_tree_mgr_name(FluName) ->
-    list_to_atom(atom_to_list(FluName) ++ "_merkle_tree_mgr").
-
-handle_load(Tid, DataDir) ->
-    Files = get_files(DataDir),
-    lists:foreach(fun(F) -> load_filename(Tid, DataDir, F) end, Files).
-
-get_files(DataDir) ->
-    {_, WildPath} = machi_util:make_data_filename(DataDir, ""),
-    filelib:wildcard("*", WildPath).
-
-load_filename(Tid, DataDir, Filename) ->
-    CsumFile = machi_util:make_checksum_filename(DataDir, Filename),
-    {ok, T} = machi_csum_table:open(CsumFile, []),
-    %% docs say that the traversal order of ets:foldl is non-determinstic 
-    %% but hopefully since csum_table uses an ordered set that's not true...
-    {_LastPosition, M} = machi_csum_table:foldl_chunks(fun insert_csum/2,
-                                                       {?MINIMUM_OFFSET, ?NEW_MERKLET}, T),
-    true = ets:insert_new(Tid, #mt{ filename = Filename, tree = M}),
-    ok = machi_csum_table:close(T),
-    ok.
-
-insert_csum({Last, Size, _Csum}=In, {Last, MT}) ->
-    %% no gap here, insert a record
-    {Last+Size, update_merkle_tree(In, MT)};
-insert_csum({Offset, Size, _Csum}=In, {Last, MT}) ->
-    %% gap here, insert unwritten record 
-    %% *AND* insert written record
-    Hole = Offset - Last,
-    MT0 = update_merkle_tree({Last, Hole, unwritten}, MT),
-    {Offset+Size, update_merkle_tree(In, MT0)}.
-
-insert(Tid, Filename, Term) ->
-    case ets:lookup(Tid, Filename) of
-        [] -> error(not_found); %% TODO: Something better?
-        [R] -> 
-            NewMT = update_merkle_tree(Term, R#mt.tree),
-            %% we choose update_element because it
-            %% makes atomic changes so it is concurrent
-            %% safe. The regular 'insert' function
-            %% does not provide that guarantee.
-            true = ets:update_element(Tid, Filename, {#mt.tree, NewMT}),
-            ok
-    end.
-
-handle_fetch(Tid, Filename) ->
-    case ets:lookup(Tid, Filename) of
-        [] -> undefined;
-        [R] -> R#mt.tree
-    end.
-
-update_merkle_tree({Offset, Size, unwritten}, MT) ->
-    merklet:insert({?ENCODE(Offset, Size), ?UNWRITTEN}, MT);
-update_merkle_tree({Offset, Size, trimmed}, MT) ->
-    merklet:insert({?ENCODE(Offset, Size), ?TRIMMED}, MT);
-update_merkle_tree({Offset, Size, Csum}, MT) ->
-    merklet:insert({?ENCODE(Offset, Size), Csum}, MT).

test/machi_merkle_tree_test.erl

@@ -18,7 +18,7 @@
 %%
 %% -------------------------------------------------------------------
 
--module(machi_merkle_tree_mgr_test).
+-module(machi_merkle_tree_test).
 -compile([export_all]).
 
 -include_lib("eunit/include/eunit.hrl").
@@ -27,6 +27,16 @@
 -define(TESTFILE, "yza^4c784dc2-19bf-4ac6-91f6-58bbe5aa88e0^1").
 -define(GAP_CHANCE, 0.10).
 
+choose_filename() ->
+    random_from_list([
+        "def^c5ea7511-d649-47d6-a8c3-2b619379c237^1",
+        "jkl^b077eff7-b2be-4773-a73f-fea4acb8a732^1",
+        "stu^553fa47a-157c-4fac-b10f-2252c7d8c37a^1",
+        "vwx^ae015d68-7689-4c9f-9677-926c6664f513^1",
+        "yza^4c784dc2-19bf-4ac6-91f6-58bbe5aa88e0^1"
+                     ]).
+
+
 make_csum_file(DataDir, Filename, Offsets) ->
     Path = machi_util:make_checksum_filename(DataDir, Filename),
     filelib:ensure_dir(Path),
@@ -82,19 +92,38 @@ generate_offsets(FH, Filesize, Current, Acc) when Current < Filesize ->
 generate_offsets(_FH, _Filesize, _Current, Acc) ->
     lists:reverse(Acc).
 
-test() ->
+test() -> 
+    test(100).
+
+test(N) ->
+    {ok, F} = file:open("results.txt", [raw, write]),
+    lists:foreach(fun(X) -> format_and_store(F, run_test(X)) end, lists:seq(1, N)).
+
+format_and_store(F, {OffsetNum, {MTime, MSize}, {NTime, NSize}}) ->
+    S = io_lib:format("~w\t~w\t~w\t~w\t~w\n", [OffsetNum, MTime, MSize, NTime, NSize]),
+    ok = file:write(F, S).
+
+run_test(C) ->
     random:seed(os:timestamp()),
-    O = make_offsets("test/" ++ ?TESTFILE),
+    OffsetFn = "test/" ++ choose_filename(),
-    ?debugFmt("Offsets: ~p", [O]),
+    O = make_offsets(OffsetFn),
-    make_csum_file(".", ?TESTFILE, O),
+    Fn = "csum_" ++ integer_to_list(C),
+    make_csum_file(".", Fn, O),
 
-    _ = machi_merkle_tree_mgr:start_link(test, ".", []),
+    Osize = length(O),
-    machi_merkle_tree_mgr:initialize(test, ?TESTFILE),
-    timer:sleep(1000),
-    All = machi_merkle_tree_mgr:fetch(test, ?TESTFILE),
-    ?debugFmt("All: ~p~n", [All]),
-    timer:sleep(1000),
-    All = machi_merkle_tree_mgr:fetch(test, ?TESTFILE),
-    ?debugFmt("All: ~p~n", [All]),
-    ok.
 
+    {MTime, {ok, M}} = timer:tc(fun() -> machi_merkle_tree:open(Fn, ".", merklet) end),
+    {NTime, {ok, N}} = timer:tc(fun() -> machi_merkle_tree:open(Fn, ".", naive) end),
+
+    ?assertEqual(Fn, machi_merkle_tree:filename(M)),
+    ?assertEqual(Fn, machi_merkle_tree:filename(N)),
+
+    MTree = machi_merkle_tree:tree(M),
+    MSize = byte_size(term_to_binary(MTree)),
+
+    NTree = machi_merkle_tree:tree(N),
+    NSize = byte_size(term_to_binary(NTree)),
+
+    ?assertEqual(same, machi_merkle_tree:diff(N, N)),
+    ?assertEqual(same, machi_merkle_tree:diff(M, M)),
+    {Osize, {MTime, MSize}, {NTime, NSize}}.