From 6232b624e10c91c8dd37206147c3672cdccd4836 Mon Sep 17 00:00:00 2001
From: Andrew Cady <d@jerkface.net>
Date: Tue, 27 Aug 2024 21:32:45 -0400
Subject: the magic breaks top restarts somehow??

---
 src/twopane.bash | 57 +++++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 48 insertions(+), 9 deletions(-)

diff --git a/src/twopane.bash b/src/twopane.bash
index 6003b8e..fe61dc2 100755
--- a/src/twopane.bash
+++ b/src/twopane.bash
@@ -120,12 +120,12 @@ layout save 0
 
 with_screen_pane()
 {
-        (( $# > 1 )) || return
+        (( $# >= 2 )) || return
         declare -i PANE="$1" LOCK
         (( PANE > 0 )) || return
         (
                 flock $LOCK
-                "$2" "$1" "${@:3}"
+                "${@:2}"
         ) {LOCK}>"$TWOPANE"/pane$PANE
 }
 
@@ -162,7 +162,7 @@ start_screen_pane()
         fi
         TOP_TITLE="Command: ${*@Q}"
         screen -X focus top
-        screen -X screen -ln -t "$TOP_TITLE" 1 "$@"
+        screen -X screen -ln -t "$TOP_TITLE" "$PANE" "$@"
         start_screen_pane_subprocess
 }
 
@@ -170,7 +170,7 @@ start_screen_pane_subprocess()
 {
         (( PANE > 0 )) || return
         subproc_command=(
-                exec -a top-pane-tty-forward
+                exec -a gnuscreen-input-filter
                         socat
                                 UNIX-LISTEN:"$TWOPANE"/socket
                                 STDIN,cfmakeraw,opost=1,onlcr=1!!STDOUT
@@ -305,6 +305,35 @@ TOP_PANE()
         esac
 }
 
+magic_fifo()
+{
+        # Some bash magic from superuser.com.
+        # Use two PIDs instead of one inode to make fifo.  (Not just
+        # less expensive but more robust, except! uses Linux procfs.)
+        # https://superuser.com/questions/184307/bash-create-anonymous-fifo
+        declare -n fd_out="$1"
+        local fd_in reader writer
+        {
+                sleep 1 | sleep 1 &
+                reader=$!
+                writer=$(jobs -p %+)
+                disown
+        } &>/dev/null
+        exec {fd_out}>/proc/$writer/fd/1 {fd_in}</proc/$reader/fd/0
+        quiet_bg "${@:2}" <&"$fd_in"
+}
+
+ordinary_fifo()
+{
+        declare -n fd_out="$1"
+        local fifo
+        fifo=$TWOPANE/sink_${!fd}.fifo
+        mkfifo "$fifo"
+        exec {fd_out}<>"$fifo"
+        rm "$fifo"
+        quiet_bg "${@:2}" <&"$fd_out"
+}
+
 connect_sink()
 {
         (( $# > 0 )) || set -- SINK
@@ -316,7 +345,13 @@ connect_sink()
                 return
         fi
         i "sink starting: ${!fd}"
-        exec {fd}> >("${@:2}")
+
+        if false && mountpoint -q /proc
+        then
+                magic_fifo fd "${@:2}"
+        else
+                ordinary_fifo fd "${@:2}"
+        fi
         pid=$!
 }
 
@@ -349,10 +384,14 @@ quiet_bg()
 #       write to stdout
 #       write to $TOP_PANE_OUT
 # I.e.:
-#       read from /dev/tty
-#       read from the socat-coproc-forwarded /dev/tty in the top pane.
-#       write to /dev/tty
-#       write to the socat-coproc-forwarded /dev/tty in the top pane.
+#       read from /dev/tty on stdin
+#       read from the socat-coproc forwarding the top pane's tty input.
+#       write to /dev/tty on stdout
+#       write to the socat-coproc forwarding tty input into the top pane.
+#
+#       For the network it is just an echo,
+#       here we could place an input filter,
+#       but we have none.
 echo_sender()
 {
         (exec -a echo_sender socat - fd:${TOP_PANE_IN?$0: Internal error}!!-) |
-- 
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