ssh: Change send_buf implementation from list to queue

A queue is the behaviour that we want, so this makes the code
easier to understand and more effective.

2 files changed, 60 insertions, 49 deletions

diff --git a/lib/ssh/src/ssh_connection.erl b/lib/ssh/src/ssh_connection.erl
index c66f810948..e9b4547aef 100644
--- a/lib/ssh/src/ssh_connection.erl
+++ b/lib/ssh/src/ssh_connection.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 2008-2014. All Rights Reserved.
+%% Copyright Ericsson AB 2008-2015. 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
@@ -326,9 +326,7 @@ channel_data(ChannelId, DataType, Data,
 						    SendDataType,
 						    SendData)}
 			  end, SendList),
-	    FlowCtrlMsgs = flow_control(Replies, 
-					Channel,
-					Cache),
+	    FlowCtrlMsgs = flow_control(Replies, Channel, Cache),
 	    {{replies, Replies ++ FlowCtrlMsgs}, Connection};
 	_ ->
 	    gen_fsm:reply(From, {error, closed}),
@@ -523,7 +521,9 @@ handle_msg(#ssh_msg_channel_open{channel_type = "forwarded-tcpip" = Type,
 			       recv_window_size = LWindowSz,
 			       recv_packet_size = LPacketSz,
 			       send_window_size = RWindowSz,
-			       send_packet_size = RPacketSz},
+			       send_packet_size = RPacketSz,
+			       send_buf = queue:new()
+			      },
 	    ssh_channel:cache_update(Cache, Channel),
 	    OpenConfMsg = channel_open_confirmation_msg(RemoteId, ChannelId,
 							LWindowSz, LPacketSz),
@@ -929,6 +929,7 @@ setup_session(#connection{channel_cache = Cache} = Connection0,
 		       recv_packet_size = ?DEFAULT_PACKET_SIZE,
 		       send_window_size = WindowSize,
 		       send_packet_size = PacketSize,
+		       send_buf = queue:new(),
 		       remote_id = RemoteId
 		      },
     ssh_channel:cache_update(Cache, Channel),
@@ -1024,63 +1025,71 @@ request_reply_or_data(#channel{local_id = ChannelId, user = ChannelPid},
 
 update_send_window(Channel, _, undefined,
 		   #connection{channel_cache = Cache}) ->
-    do_update_send_window(Channel,  Channel#channel.send_buf, Cache);
+    do_update_send_window(Channel, Cache);
 
-update_send_window(Channel, DataType, Data,
+update_send_window(#channel{send_buf = SendBuffer} = Channel, DataType, Data,
 		   #connection{channel_cache = Cache}) ->
-    do_update_send_window(Channel, Channel#channel.send_buf ++ [{DataType, Data}], Cache).
+    do_update_send_window(Channel#channel{send_buf = queue:in({DataType, Data}, SendBuffer)},
+			  Cache).
 
-do_update_send_window(Channel0, Buf0, Cache) ->
-    {Buf1, NewSz, Buf2} = get_window(Buf0, 
-				     Channel0#channel.send_packet_size,
-				     Channel0#channel.send_window_size),
-
-    Channel = Channel0#channel{send_window_size = NewSz, send_buf = Buf2},
+do_update_send_window(Channel0, Cache) ->
+    {SendMsgs, Channel} = get_window(Channel0, []),
     ssh_channel:cache_update(Cache, Channel), 
-    {Buf1, Channel}.
-
-get_window(Bs, PSz, WSz) ->
-    get_window(Bs, PSz, WSz, []).
-
-get_window(Bs, _PSz, 0, Acc) ->
-    {lists:reverse(Acc), 0, Bs};
-get_window([B0 = {DataType, Bin} | Bs], PSz, WSz, Acc) ->
-    BSz = size(Bin),
-    if BSz =< WSz ->  %% will fit into window
-	    if BSz =< PSz ->  %% will fit into a packet
-		    get_window(Bs, PSz, WSz-BSz, [B0|Acc]);
-	       true -> %% split into packet size
-		    <<Bin1:PSz/binary, Bin2/binary>> = Bin,
-		    get_window([setelement(2, B0, Bin2) | Bs],
-			       PSz, WSz-PSz, 
-			       [{DataType, Bin1}|Acc])
+    {SendMsgs, Channel}.
+
+get_window(#channel{send_window_size = 0
+		   } = Channel, Acc) ->
+    {lists:reverse(Acc), Channel};
+get_window(#channel{send_buf = Buffer, 
+		    send_packet_size = PacketSize,
+		    send_window_size = WindowSize0
+		   } = Channel, Acc0) ->
+    case queue:out(Buffer) of
+	{{value, {_, Data} = Msg}, NewBuffer} ->
+	    case handle_send_window(Msg, size(Data), PacketSize, WindowSize0, Acc0) of		
+		{WindowSize, Acc, {_, <<>>}} ->
+		    {lists:reverse(Acc), Channel#channel{send_window_size = WindowSize,
+							 send_buf = NewBuffer}};
+		{WindowSize, Acc, Rest} ->
+		    get_window(Channel#channel{send_window_size = WindowSize,
+					       send_buf = queue:in_r(Rest, NewBuffer)}, Acc)
 	    end;
-       WSz =< PSz ->  %% use rest of window
-	    <<Bin1:WSz/binary, Bin2/binary>> = Bin,
-	    get_window([setelement(2, B0, Bin2) | Bs],
-		       PSz, WSz-WSz, 
-		       [{DataType, Bin1}|Acc]);
-       true -> %% use packet size
-	    <<Bin1:PSz/binary, Bin2/binary>> = Bin,
-	    get_window([setelement(2, B0, Bin2) | Bs],
-		       PSz, WSz-PSz, 
-		       [{DataType, Bin1}|Acc])
+	{empty, NewBuffer} ->
+	    {[], Channel#channel{send_buf = NewBuffer}}
+    end.
+
+handle_send_window(Msg = {Type, Data}, Size, PacketSize, WindowSize, Acc) when Size =< WindowSize ->
+    case Size =< PacketSize of
+	true ->
+	    {WindowSize - Size, [Msg | Acc], {Type, <<>>}};
+	false ->
+	    <<Msg1:PacketSize/binary, Msg2/binary>> = Data,
+	    {WindowSize - PacketSize, [{Type, Msg1} | Acc], {Type, Msg2}}
     end;
-get_window([], _PSz, WSz, Acc) ->
-    {lists:reverse(Acc), WSz, []}.
+handle_send_window({Type, Data}, _, PacketSize, WindowSize, Acc) when WindowSize =< PacketSize ->
+    <<Msg1:WindowSize/binary, Msg2/binary>> = Data,
+    {WindowSize - WindowSize, [{Type, Msg1} | Acc], {Type, Msg2}};
+handle_send_window({Type, Data}, _, PacketSize, WindowSize, Acc) ->
+    <<Msg1:PacketSize/binary, Msg2/binary>> = Data,
+    {WindowSize - PacketSize, [{Type, Msg1} | Acc], {Type, Msg2}}.
 
 flow_control(Channel, Cache) ->
     flow_control([window_adjusted], Channel, Cache).
-				    
+
 flow_control([], Channel, Cache) ->
     ssh_channel:cache_update(Cache, Channel),
     [];
-
 flow_control([_|_], #channel{flow_control = From,
-			     send_buf = []} = Channel, Cache) when From =/= undefined ->
-	[{flow_control, Cache, Channel, From, ok}];
+			     send_buf = Buffer} = Channel, Cache) when From =/= undefined ->
+    case queue:is_empty(Buffer) of
+	true ->
+	    ssh_channel:cache_update(Cache, Channel#channel{flow_control = undefined}),
+	    [{flow_control, Cache, Channel, From, ok}];
+	false ->
+	    []
+    end;
 flow_control(_,_,_) ->
-	[].
+    [].
 
 pty_req(ConnectionHandler, Channel, Term, Width, Height,
 	 PixWidth, PixHeight, PtyOpts, TimeOut) ->
diff --git a/lib/ssh/src/ssh_connection_handler.erl b/lib/ssh/src/ssh_connection_handler.erl
index 1610364287..e1f2e059e8 100644
--- a/lib/ssh/src/ssh_connection_handler.erl
+++ b/lib/ssh/src/ssh_connection_handler.erl
@@ -751,7 +751,9 @@ handle_sync_event({open, ChannelPid, Type, InitialWindowSize, MaxPacketSize, Dat
 		       user = ChannelPid,
 		       local_id = ChannelId,
 		       recv_window_size = InitialWindowSize,
-		       recv_packet_size = MaxPacketSize},
+		       recv_packet_size = MaxPacketSize,
+		       send_buf = queue:new()
+		      },
     ssh_channel:cache_update(Cache, Channel),
     State = add_request(true, ChannelId, From, State2),
     start_timeout(ChannelId, From, Timeout),