chore(frame): avoid using 0 to signal "some more" bytes expected

keynslug · keynslug · commit 566e73af8f14 · 2025-07-22T14:00:09.000+02:00
diff --git a/apps/emqx/src/emqx_frame.erl b/apps/emqx/src/emqx_frame.erl
@@ -56,8 +56,8 @@
 -type parse_state_initial() :: #options{}.
 
 -type parse_result() ::
-    %% Need more bytes out of stream, `0` means it's unclear how much more.
-    {_NeedMore :: non_neg_integer(), parse_state()}
+    %% Need more bytes out of stream.
+    {some_more | _NBytesMore :: pos_integer(), parse_state()}
     %% There's a full packet.
     | {emqx_types:packet(), binary(), parse_state_initial()}.
 
@@ -144,7 +144,7 @@ parse(
 ) ->
     parse_body_frame(Bin, Header, Need, Body, Options);
 parse(<<>>, State) ->
-    {0, State}.
+    {some_more, State}.
 
 %% @doc Parses _complete_ binary frame into a single `#mqtt_packet{}`.
 -spec parse_complete(iodata(), parse_state_initial()) ->
@@ -170,7 +170,7 @@ parse_complete(
     end.
 
 parse_remaining_len(<<>>, Header, Mult, Length, Options) ->
-    {_NeedMore = 0, #remlen{hdr = Header, len = Length, mult = Mult, opts = Options}};
+    {some_more, #remlen{hdr = Header, len = Length, mult = Mult, opts = Options}};
 parse_remaining_len(<<0:8, Rest/binary>>, Header, 1, 0, Options) ->
     Packet = parse_bodyless_packet(Header),
     {Packet, Rest, Options};
diff --git a/apps/emqx/src/emqx_socket_connection.erl b/apps/emqx/src/emqx_socket_connection.erl
@@ -428,6 +428,8 @@ wakeup_from_hib(Parent, State) ->
 
 -compile({inline, [sock_async_recv/2]}).
 
+sock_async_recv(Socket, some_more) ->
+    socket:recv(Socket, 0, [], nowait);
 sock_async_recv(Socket, Len) ->
     socket:recv(Socket, Len, [], nowait).
 
diff --git a/apps/emqx/test/emqx_frame_SUITE.erl b/apps/emqx/test/emqx_frame_SUITE.erl
@@ -125,8 +125,8 @@ t_parse_cont(_) ->
     Packet = ?CONNECT_PACKET(#mqtt_packet_connect{}),
     ParseState = emqx_frame:initial_parse_state(),
     <<HdrBin:1/binary, LenBin:1/binary, RestBin/binary>> = serialize_to_binary(Packet),
-    {0, ContParse} = emqx_frame:parse(<<>>, ParseState),
-    {0, ContParse1} = emqx_frame:parse(HdrBin, ContParse),
+    {some_more, ContParse} = emqx_frame:parse(<<>>, ParseState),
+    {some_more, ContParse1} = emqx_frame:parse(HdrBin, ContParse),
     {12, ContParse2} = emqx_frame:parse(LenBin, ContParse1),
     {12, ContParse3} = emqx_frame:parse(<<>>, ContParse2),
     {Packet, <<>>, _} = emqx_frame:parse(RestBin, ContParse3).

Original file line number	Diff line number	Diff line change
`@@ -428,6 +428,8 @@ wakeup_from_hib(Parent, State) ->`
`428`	`428`
`429`	`429`	`-compile({inline, [sock_async_recv/2]}).`
`430`	`430`
	`431`	`+sock_async_recv(Socket, some_more) ->`
	`432`	`+ socket:recv(Socket, 0, [], nowait);`
`431`	`433`	`sock_async_recv(Socket, Len) ->`
`432`	`434`	`socket:recv(Socket, Len, [], nowait).`
`433`	`435`