1 files changed, 92 insertions, 0 deletions
diff --git a/src/fabric_update_docs.erl b/src/fabric_update_docs.erl
new file mode 100644
index 00000000..00c7e9d7
--- /dev/null
+++ b/src/fabric_update_docs.erl
@@ -0,0 +1,92 @@
+-module(fabric_update_docs).
+-export([go/3]).
+-include("fabric.hrl").
+
+go(DbName, AllDocs, Options) ->
+    GroupedDocs = lists:map(fun({#shard{name=Name, node=Node} = Shard, Docs}) ->
+        Ref = rexi:cast(Node, {fabric_rpc, update_docs, [Name, Docs, Options]}),
+        {Shard#shard{ref=Ref}, Docs}
+    end, group_docs_by_shard(DbName, AllDocs)),
+    {Workers, _} = lists:unzip(GroupedDocs),
+    Acc0 = {length(Workers), length(AllDocs), couch_util:get_value(w, Options, 1),
+        GroupedDocs, dict:new()},
+    case fabric_util:recv(Workers, #shard.ref, fun handle_message/3, Acc0) of
+    {ok, Results} ->
+        {ok, couch_util:reorder_results(AllDocs, Results)};
+    Else ->
+        Else
+    end.
+
+handle_message(_Worker, {rexi_DOWN, _, _, _}, Acc0) ->
+    skip_message(Acc0);
+handle_message(_Worker, {rexi_EXIT, _}, Acc0) ->
+    skip_message(Acc0);
+handle_message(Worker, {ok, Replies}, Acc0) ->
+    {WaitingCount, DocCount, W, GroupedDocs, DocReplyDict0} = Acc0,
+    Docs = couch_util:get_value(Worker, GroupedDocs),
+    DocReplyDict = append_update_replies(Docs, Replies, DocReplyDict0),
+    case {WaitingCount, dict:size(DocReplyDict)} of
+    {1, _} ->
+        % last message has arrived, we need to conclude things
+        {W, Reply} = dict:fold(fun force_reply/3, {W,[]}, DocReplyDict),
+        {stop, Reply};
+    {_, DocCount} ->
+        % we've got at least one reply for each document, let's take a look
+        case dict:fold(fun maybe_reply/3, {stop,W,[]}, DocReplyDict) of
+        continue ->
+            {ok, {WaitingCount - 1, DocCount, W, GroupedDocs, DocReplyDict}};
+        {stop, W, FinalReplies} ->
+            {stop, FinalReplies}
+        end;
+    {_, N} when N < DocCount ->
+        % no point in trying to finalize anything yet
+        {ok, {WaitingCount - 1, DocCount, W, GroupedDocs, DocReplyDict}}
+    end.
+
+force_reply(Doc, Replies, {W, Acc}) ->
+    % TODO make a real decision here
+    case Replies of
+    [] ->
+        {W, [{Doc, {error, internal_server_error}} | Acc]};
+    [Reply| _] ->
+        {W, [{Doc, Reply} | Acc]}
+    end.
+
+maybe_reply(_, _, continue) ->
+    % we didn't meet quorum for all docs, so we're fast-forwarding the fold
+    continue;
+maybe_reply(Doc, Replies, {stop, W, Acc}) ->
+    case update_quorum_met(W, Replies) of
+    {true, Reply} ->
+        {stop, W, [{Doc, Reply} | Acc]};
+    false ->
+        continue
+    end.
+
+update_quorum_met(W, Replies) ->
+    % TODO make a real decision here
+    case length(Replies) >= W of
+    true ->
+        {true, hd(Replies)};
+    false ->
+        false
+    end.
+
+-spec group_docs_by_shard(binary(), [#doc{}]) -> [{#shard{}, [#doc{}]}].
+group_docs_by_shard(DbName, Docs) ->
+    dict:to_list(lists:foldl(fun(#doc{id=Id} = Doc, D0) ->
+        lists:foldl(fun(Shard, D1) ->
+            dict:append(Shard, Doc, D1)
+        end, D0, partitions:for_key(DbName,Id))
+    end, dict:new(), Docs)).
+
+append_update_replies([], [], DocReplyDict) ->
+    DocReplyDict;
+append_update_replies([Doc|Rest1], [Reply|Rest2], Dict0) ->
+    % TODO what if the same document shows up twice in one update_docs call?
+    append_update_replies(Rest1, Rest2, dict:append(Doc, Reply, Dict0)).
+
+skip_message(Acc0) ->
+    % TODO fix this
+    {ok, Acc0}.
+