File 0240-kernel-gen-tcp-socket-Handle-buffered-data... of Package erlang

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File 0240-kernel-gen-tcp-socket-Handle-buffered-data-when-acti.patch of Package erlang (Revision c37f636f556d133a129c9e9a7093d763)

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From 85be6e52206895a624481a152162e83b5d8b64bb Mon Sep 17 00:00:00 2001
From: Micael Karlberg <bmk@erlang.org>
Date: Fri, 23 Jul 2021 19:04:08 +0200
Subject: [PATCH 2/2] [kernel|gen-tcp-socket] Handle buffered data when
 activating

If the socket is deactivated; active: once | true | N > 0 -> false
we do not cancel any select! Data that arrive during the phase when
we are in state 'recv' but are inactive is simply stored in the buffer.
Then if activated: active: false -> once | true | N > 0,
we need to check if there is something in our buffers, and maybe deliver
it to its owner. This should only occure if we are in state connected
(state 'recv' and in-active when data arrives => put data in buffer and
then enter state 'connected', since we are in-active).

OTP-17156
---
 lib/kernel/src/gen_tcp_socket.erl | 106 ++++++++++++++++++++++++++++--
 1 file changed, 101 insertions(+), 5 deletions(-)

diff --git a/lib/kernel/src/gen_tcp_socket.erl b/lib/kernel/src/gen_tcp_socket.erl
index 815a1079ec..53ffc515c2 100644
--- a/lib/kernel/src/gen_tcp_socket.erl
+++ b/lib/kernel/src/gen_tcp_socket.erl
@@ -1452,14 +1452,21 @@ handle_event({call, From}, {setopts, Opts}, State, {P, D}) ->
 	    ok = socket:setopt(P#params.socket, {otp,meta}, meta(D_1))
     end,
     Reply = {reply, From, Result},
+
+    %% If the socket is deactivated; active: once | true | N > 0 -> false
+    %% we do not cancel any select! Data that arrive during the phase when
+    %% we are in state 'recv' but are inactive is simply stored in the buffer.
+    %% If activated: active: false -> once | true | N > 0
+    %% We need to check if there is something in our buffers, and maybe deliver
+    %% it to its owner. This is what we do here. This should only occure
+    %% if we are in state connected (state 'recv' and in-active when data
+    %% arrives => put data in buffer and then enter state 'connected', since
+    %% we are in-active).
     case State of
         'connected' ->
-            handle_connected(
-              P, D_1,
-              [Reply]);
+            handle_connected(P, handle_buffered(P, D_1), [Reply]);
         _ ->
-            {keep_state, {P, D_1},
-             [Reply]}
+            {keep_state, {P, D_1}, [Reply]}
     end;
 
 %% Call: getstat/2
@@ -1934,6 +1941,95 @@ handle_recv_peek(P, D, ActionsR, Packet, Data) ->
             handle_recv_length(P, D, ActionsR, Packet + N)
     end.
 
+
+handle_buffered(_P, #{recv_from := _From} = D) ->
+    D;
+handle_buffered(P, #{active := Active} = D) when (Active =/= false) ->
+    case D of
+        #{buffer := Buffer} when is_list(Buffer) andalso (Buffer =/= []) ->
+            Data = condense_buffer(Buffer),
+            handle_buffered(P, D, Data);
+        #{buffer := Data} when is_binary(Data) andalso (byte_size(Data) > 0) ->
+            handle_buffered(P, D, Data);
+        _ ->
+            D
+    end;
+handle_buffered(_P, D) ->
+    D.
+
+handle_buffered(P,
+                #{packet         := line,
+                  line_delimiter := LineDelimiter,
+                  packet_size    := PacketSize} = D,
+                Data) ->
+    DecodeOpts = [{line_delimiter, LineDelimiter},
+		  {line_length,    PacketSize}],
+    handle_buffered(P, D, Data, DecodeOpts);
+handle_buffered(P, D, Data) ->
+    handle_buffered(P, D, Data, []).
+
+handle_buffered(P, #{packet_size := PacketSize} = D,
+                Data, DecocdeOpts0) ->
+    DecodeOpts = [{packet_size, PacketSize}|DecocdeOpts0], 
+    Type       = decode_packet(D),
+    case erlang:decode_packet(Type, Data, DecodeOpts) of
+        {ok, Decoded, Rest} ->
+            D2 = deliver_buffered_data(P, D, Decoded),
+            %% Prepare the rest
+            %% is_list(Buffer) -> try to decode first
+            %% is_binary(Buffer) -> get more data first
+            Buffer =
+                case Rest of
+                    <<>> -> Rest;
+                    <<_/binary>> -> [Rest]
+                end,
+            D2#{buffer := Buffer};
+        {more, _} ->
+            D;
+        {error, Reason} ->
+            %% What do we do here?
+            %% Keep the buffer and hope that it will go better with more data?
+            %% Or discard it and continue as if nothing happened?
+            error_logger:warning_msg("Failed decoding message"
+                                     "~n   Socket:          ~p"
+                                     "~n   Socket server:   ~p"
+                                     "~n   Packet type:     ~p"
+                                     "~n   byte_size(Data): ~p"
+                                     "~n   Reason:          ~p",
+                                     [P#params.socket, self(),
+                                      Type, byte_size(Data), Reason]),
+            D
+    end.
+
+%% If we get this far, we *know* that the socket is 'active'.
+deliver_buffered_data(#params{owner = Owner} = P,
+                      #{active  := Active,
+                        mode    := Mode,
+                        header  := Header,
+                        deliver := Deliver,
+                        packet  := Packet} = D, Data) ->
+    DeliverData  = deliver_data(Data, Mode, Header, Packet),
+    ModuleSocket = module_socket(P),
+    Owner !
+        case Deliver of
+            term ->
+                {tag(Packet), ModuleSocket, DeliverData};
+            port ->
+                {ModuleSocket, {data, DeliverData}}
+        end,
+    case Active of
+        true ->
+            recv_start(next_packet(D, Packet, Data));
+        once ->
+            recv_stop(next_packet(D, Packet, Data, false));
+        1 ->
+            Owner ! {tcp_passive, ModuleSocket},
+            recv_stop(next_packet(D, Packet, Data, false));
+        N when is_integer(N) ->
+            recv_start(next_packet(D, Packet, Data, Active - 1))
+    end.    
+
+
 handle_recv_packet(P, D, ActionsR) ->
     case D of
         #{buffer := Buffer} when is_list(Buffer) ->
-- 
2.31.1

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File 0240-kernel-gen-tcp-socket-Handle-buffered-data-when-acti.patch of Package erlang (Revision c37f636f556d133a129c9e9a7093d763)

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