reorganize couch .erl and driver code into rebar layout

1 files changed, 115 insertions, 0 deletions

diff --git a/apps/couch/src/couch_work_queue.erl b/apps/couch/src/couch_work_queue.erl
new file mode 100644
index 00000000..decfcad8
--- /dev/null
+++ b/apps/couch/src/couch_work_queue.erl
@@ -0,0 +1,115 @@
+% Licensed 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.
+
+-module(couch_work_queue).
+-behaviour(gen_server).
+
+-export([new/2,queue/2,dequeue/1,dequeue/2,close/1]).
+-export([init/1, terminate/2, handle_call/3, handle_cast/2, code_change/3, handle_info/2]).
+
+-record(q, {
+    queue=queue:new(),
+    blocked=[],
+    max_size,
+    max_items,
+    items=0,
+    size=0,
+    work_waiter=nil,
+    close_on_dequeue=false
+}).
+
+new(MaxSize, MaxItems) ->
+    gen_server:start_link(couch_work_queue, {MaxSize, MaxItems}, []).
+
+queue(Wq, Item) ->
+    gen_server:call(Wq, {queue, Item}, infinity).
+
+dequeue(Wq) ->
+    dequeue(Wq, all).
+    
+dequeue(Wq, MaxItems) ->
+    try gen_server:call(Wq, {dequeue, MaxItems}, infinity)
+    catch
+        _:_ -> closed
+    end.
+
+close(Wq) ->
+    gen_server:cast(Wq, close).
+    
+
+init({MaxSize,MaxItems}) ->
+    {ok, #q{max_size=MaxSize, max_items=MaxItems}}.
+
+terminate(_Reason, #q{work_waiter=nil}) ->
+    ok;
+terminate(_Reason, #q{work_waiter={WWFrom, _}}) ->
+    gen_server:reply(WWFrom, closed).
+    
+handle_call({queue, Item}, From, #q{work_waiter=nil}=Q0) ->
+    Q = Q0#q{size=Q0#q.size + byte_size(term_to_binary(Item)),
+                items=Q0#q.items + 1,
+                queue=queue:in(Item, Q0#q.queue)},
+    case (Q#q.size >= Q#q.max_size) orelse
+            (Q#q.items >= Q#q.max_items) of
+    true ->
+        {noreply, Q#q{blocked=[From | Q#q.blocked]}};
+    false ->
+        {reply, ok, Q}
+    end;
+handle_call({queue, Item}, _From, #q{work_waiter={WWFrom, _Max}}=Q) ->
+    gen_server:reply(WWFrom, {ok, [Item]}),
+    {reply, ok, Q#q{work_waiter=nil}};
+handle_call({dequeue, _Max}, _From, #q{work_waiter=WW}) when WW /= nil ->
+    exit("Only one caller allowed to wait for work at a time");
+handle_call({dequeue, Max}, From, #q{items=0}=Q) ->
+    {noreply, Q#q{work_waiter={From, Max}}};
+handle_call({dequeue, Max}, _From, #q{queue=Queue, max_size=MaxSize,
+        max_items=MaxItems, items=Items,close_on_dequeue=Close}=Q) ->
+    if Max >= Items orelse Max == all ->
+        [gen_server:reply(From, ok) || From <- Q#q.blocked],
+        Q2 = #q{max_size=MaxSize, max_items=MaxItems},
+        if Close ->
+            {stop, normal, {ok, queue:to_list(Queue)}, Q2};
+        true ->
+            {reply, {ok, queue:to_list(Queue)}, Q2}
+        end;
+    true ->
+        {DequeuedItems, Queue2, Blocked2} =
+                dequeue_items(Max, Queue, Q#q.blocked, []),
+        {reply, {ok, DequeuedItems},
+                Q#q{items=Items-Max,blocked=Blocked2,queue=Queue2}}
+    end.
+
+dequeue_items(0, Queue, Blocked, DequeuedAcc) ->
+    {lists:reverse(DequeuedAcc), Queue, Blocked};
+dequeue_items(NumItems, Queue, Blocked, DequeuedAcc) ->
+    {{value, Item}, Queue2} = queue:out(Queue),
+    case Blocked of
+    [] ->
+        Blocked2 = Blocked;
+    [From|Blocked2] ->
+        gen_server:reply(From, ok)
+    end,
+    dequeue_items(NumItems-1, Queue2, Blocked2, [Item | DequeuedAcc]).
+    
+
+handle_cast(close, #q{items=0}=Q) ->
+    {stop, normal, Q};
+handle_cast(close, Q) ->
+    {noreply, Q#q{close_on_dequeue=true}}.
+
+
+code_change(_OldVsn, State, _Extra) ->
+    {ok, State}.
+
+handle_info(X, Q) ->
+    {stop, X, Q}.