The R13B03 release.OTP_R13B03

1 files changed, 132 insertions, 0 deletions

diff --git a/lib/mnesia/src/mnesia_frag_old_hash.erl b/lib/mnesia/src/mnesia_frag_old_hash.erl
new file mode 100644
index 0000000000..817bb54eb1
--- /dev/null
+++ b/lib/mnesia/src/mnesia_frag_old_hash.erl
@@ -0,0 +1,132 @@
+%%
+%% %CopyrightBegin%
+%% 
+%% Copyright Ericsson AB 2002-2009. 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%
+%%
+
+%%
+%%%----------------------------------------------------------------------
+%%% Purpose : Implements hashing functionality for fragmented tables
+%%%----------------------------------------------------------------------
+
+-module(mnesia_frag_old_hash).
+%%-behaviour(mnesia_frag_hash).
+
+-compile({nowarn_deprecated_function, {erlang,hash,2}}).
+
+%% Hashing callback functions
+-export([
+	 init_state/2,
+	 add_frag/1,
+	 del_frag/1,
+	 key_to_frag_number/2,
+	 match_spec_to_frag_numbers/2
+	]).
+
+-record(old_hash_state,
+	{n_fragments,
+	 next_n_to_split,
+	 n_doubles}).
+
+%% Old style. Kept for backwards compatibility.
+-record(frag_hash,
+	{foreign_key,
+	 n_fragments,
+	 next_n_to_split,
+	 n_doubles}).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+init_state(_Tab, InitialState) when InitialState == undefined ->
+    #old_hash_state{n_fragments     = 1,
+		    next_n_to_split = 1,
+		    n_doubles       = 0};
+init_state(_Tab, FH) when is_record(FH, frag_hash) ->
+    %% Old style. Kept for backwards compatibility.
+    #old_hash_state{n_fragments     = FH#frag_hash.n_fragments,
+		    next_n_to_split = FH#frag_hash.next_n_to_split,
+		    n_doubles       = FH#frag_hash.n_doubles}.
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+add_frag(State) when is_record(State, old_hash_state) ->
+    SplitN = State#old_hash_state.next_n_to_split,
+    P = SplitN + 1,
+    L = State#old_hash_state.n_doubles,
+    NewN = State#old_hash_state.n_fragments + 1,
+    State2 = case trunc(math:pow(2, L)) + 1 of
+		 P2 when P2 == P ->
+		     State#old_hash_state{n_fragments = NewN,
+					  next_n_to_split = 1,
+					  n_doubles = L + 1};
+		 _ ->
+		     State#old_hash_state{n_fragments = NewN,
+					  next_n_to_split = P}
+	     end,
+    {State2, [SplitN], [NewN]}.
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+del_frag(State) when is_record(State, old_hash_state) ->
+    P = State#old_hash_state.next_n_to_split - 1,
+    L = State#old_hash_state.n_doubles,
+    N = State#old_hash_state.n_fragments,
+    if
+	P < 1 ->
+	    L2 = L - 1,
+	    MergeN = trunc(math:pow(2, L2)),
+	    State2 = State#old_hash_state{n_fragments = N - 1,
+					  next_n_to_split = MergeN,
+					  n_doubles = L2},
+	    {State2, [N], [MergeN]};
+	true ->
+	    MergeN = P,
+	    State2 = State#old_hash_state{n_fragments = N - 1,
+					  next_n_to_split = MergeN},
+	    {State2, [N], [MergeN]}
+	end.
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+key_to_frag_number(State, Key) when is_record(State, old_hash_state) ->
+    L = State#old_hash_state.n_doubles,
+    A = erlang:hash(Key, trunc(math:pow(2, L))),
+    P = State#old_hash_state.next_n_to_split,
+    if
+	A < P ->
+	    erlang:hash(Key, trunc(math:pow(2, L + 1)));
+	true ->
+	    A
+    end.
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+match_spec_to_frag_numbers(State, MatchSpec) when is_record(State, old_hash_state) ->
+    case MatchSpec of
+	[{HeadPat, _, _}] when is_tuple(HeadPat), tuple_size(HeadPat) > 2 ->
+	    KeyPat = element(2, HeadPat),
+	    case has_var(KeyPat) of
+		false ->
+		    [key_to_frag_number(State, KeyPat)];
+		true ->
+		    lists:seq(1, State#old_hash_state.n_fragments)
+	    end;
+	_ -> 
+	    lists:seq(1, State#old_hash_state.n_fragments)
+    end.
+
+has_var(Pat) ->
+    mnesia:has_var(Pat).