kernel: support sending raw byte data over stdout

After rewriting the shell, group.erl converts everything to Unicode.
However, this is problematic if you want to send raw byte data over
stdout which may contain Erlang terms converted to binary that you
want to convert back to Erlang term after data transfer.
If io:setopts(_, {encoding, latin1}) is set, group.erl will just send
the data directly to user_drv.erl which will send the data to
prim_tty.erl without converting it to Unicode.

3 files changed, 33 insertions, 11 deletions

diff --git a/lib/kernel/src/group.erl b/lib/kernel/src/group.erl
index 665b326ea0..311c2f3c5e 100644
--- a/lib/kernel/src/group.erl
+++ b/lib/kernel/src/group.erl
@@ -40,6 +40,7 @@ server(Ancestors, Drv, Shell, Options) ->
     put(line_buffer, proplists:get_value(line_buffer, Options, group_history:load())),
     put(read_mode, list),
     put(user_drv, Drv),
+    put(unicode_state, true),
     ExpandFun = normalize_expand_fun(Options, fun edlin_expand:expand/2),
     put(expand_fun, ExpandFun),
     put(echo, proplists:get_value(echo, Options, true)),
@@ -239,17 +240,27 @@ io_request({put_chars,unicode,M,F,As}, Drv, _Shell, From, Buf) ->
 	    end
     end;
 io_request({put_chars,latin1,Binary}, Drv, _Shell, From, Buf) when is_binary(Binary) ->
-    send_drv(Drv, {put_chars_sync, unicode,
-                   unicode:characters_to_binary(Binary,latin1),
-                   From}),
+    IsUnicode = get(unicode_state),
+    if IsUnicode ->
+            send_drv(Drv,
+                     {put_chars_sync, unicode,
+                      unicode:characters_to_binary(Binary,latin1),
+                      From});
+        true ->
+            send_drv(Drv, {put_chars_sync, latin1, Binary, From})
+    end,
     {noreply,Buf};
 io_request({put_chars,latin1,Chars}, Drv, _Shell, From, Buf) ->
-    case catch unicode:characters_to_binary(Chars,latin1) of
-	Binary when is_binary(Binary) ->
-	    send_drv(Drv, {put_chars_sync, unicode, Binary, From}),
-	    {noreply,Buf};
-	_ ->
-	    {error,{error,{put_chars,latin1,Chars}},Buf}
+    IsUnicode = get(unicode_state),
+    if IsUnicode ->
+            case catch unicode:characters_to_binary(Chars,latin1) of
+                Binary when is_binary(Binary) ->
+                    send_drv(Drv, {put_chars_sync, unicode, Binary, From}),
+                    {noreply,Buf};
+                _ ->
+                    {error,{error,{put_chars,latin1,Chars}},Buf}
+            end;
+        true -> send_drv(Drv, {put_chars_sync, latin1, Chars, From})
     end;
 io_request({put_chars,latin1,M,F,As}, Drv, _Shell, From, Buf) ->
     case catch apply(M, F, As) of
@@ -396,9 +407,11 @@ do_setopts(Opts, Drv, Buf) ->
     put(echo, proplists:get_value(echo, Opts, get(echo))),
     case proplists:get_value(encoding,Opts) of
 	Valid when Valid =:= unicode; Valid =:= utf8 ->
-	    set_unicode_state(Drv,true);
+           set_unicode_state(Drv,true),
+           put(unicode_state, true);
 	latin1 ->
-	    set_unicode_state(Drv,false);
+           set_unicode_state(Drv,false),
+           put(unicode_state, false);
 	_ ->
 	    ok
     end,
diff --git a/lib/kernel/src/prim_tty.erl b/lib/kernel/src/prim_tty.erl
index 7ed418de5e..4ef10c752d 100644
--- a/lib/kernel/src/prim_tty.erl
+++ b/lib/kernel/src/prim_tty.erl
@@ -164,6 +164,7 @@
                       sig => boolean()
                     }.
 -type request() ::
+        {putc_raw, binary()} |
         {putc, unicode:unicode_binary()} |
         {expand, unicode:unicode_binary()} |
         {insert, unicode:unicode_binary()} |
@@ -525,6 +526,8 @@ writer_loop(TTY, WriterRef) ->
 -spec handle_request(state(), request()) -> {erlang:iovec(), state()}.
 handle_request(State = #state{ options = #{ tty := false } }, Request) ->
     case Request of
+        {putc_raw, Binary} ->
+            {Binary, State};
         {putc, Binary} ->
             {encode(Binary, State#state.unicode), State};
         beep ->
@@ -565,6 +568,8 @@ handle_request(State = #state{ unicode = U }, {putc, Binary}) ->
             {_, _, _, NewBA} = split(NewLength - OldLength, NewState#state.buffer_after, U),
             {encode(PutBuffer, U), NewState#state{ buffer_after = NewBA }}
     end;
+handle_request(State, {putc_raw, Binary}) ->
+    handle_request(State, {putc, unicode:characters_to_binary(Binary, latin1)});
 handle_request(State = #state{ unicode = U }, {delete, N}) when N > 0 ->
     {_DelNum, DelCols, _, NewBA} = split(N, State#state.buffer_after, U),
     BBCols = cols(State#state.buffer_before, U),
diff --git a/lib/kernel/src/user_drv.erl b/lib/kernel/src/user_drv.erl
index bcc0d2b78b..fc1a4434fb 100644
--- a/lib/kernel/src/user_drv.erl
+++ b/lib/kernel/src/user_drv.erl
@@ -765,6 +765,10 @@ io_request({put_chars_sync, unicode, Chars, Reply}, TTY) ->
     {Output, NewTTY} = prim_tty:handle_request(TTY, {putc, unicode:characters_to_binary(Chars)}),
     {ok, MonitorRef} = prim_tty:write(NewTTY, Output, self()),
     {Reply, MonitorRef, NewTTY};
+io_request({put_chars_sync, latin1, Chars, Reply}, TTY) ->
+    {Output, NewTTY} = prim_tty:handle_request(TTY, {putc_raw, Chars}),
+    {ok, MonitorRef} = prim_tty:write(NewTTY, Output, self()),
+    {Reply, MonitorRef, NewTTY};
 io_request({put_expand, unicode, Chars}, TTY) ->
     write(prim_tty:handle_request(TTY, {expand, unicode:characters_to_binary(Chars)}));
 io_request({move_rel, N}, TTY) ->