From cc1f0bc3fe674ee6cf33c15b43a9e60faee9762a Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Mon, 23 Jan 2023 16:07:00 +0530
Subject: [PATCH] Function to drain controlling tty

---
 tools/tty/tty.go        | 22 ++++++++++++++++++++++
 tools/tui/loop/read.go  |  4 +++-
 tools/tui/loop/write.go |  4 +++-
 tools/utils/select.go   |  2 +-
 4 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/tools/tty/tty.go b/tools/tty/tty.go
index aa6238cae..1542a59f5 100644
--- a/tools/tty/tty.go
+++ b/tools/tty/tty.go
@@ -315,3 +315,25 @@ func DebugPrintln(a ...any) {
 		term.DebugPrintln(a...)
 	}
 }
+
+func DrainControllingTTY(wait_for time.Duration) {
+	tty, err := OpenControllingTerm(SetRaw, SetNoEcho)
+	if err != nil {
+		return
+	}
+	sel := utils.CreateSelect(1)
+	sel.RegisterRead(tty.Fd())
+	for {
+		n, err := sel.Wait(wait_for)
+		if err == unix.EINTR {
+			continue
+		}
+		if err != nil {
+			return
+		}
+		if n > 0 && sel.IsReadyToRead(tty.Fd()) {
+			tty.Read(make([]byte, 256))
+		}
+		break
+	}
+}
diff --git a/tools/tui/loop/read.go b/tools/tui/loop/read.go
index f7693e3d2..671864618 100644
--- a/tools/tui/loop/read.go
+++ b/tools/tui/loop/read.go
@@ -7,6 +7,8 @@ import (
 	"io"
 	"os"
 
+	"golang.org/x/sys/unix"
+
 	"kitty/tools/tty"
 	"kitty/tools/utils"
 )
@@ -56,7 +58,7 @@ func read_from_tty(pipe_r *os.File, term *tty.Term, results_channel chan<- []byt
 	wait_for_read_available := func() {
 		for {
 			n, err := selector.WaitForever()
-			if err != nil {
+			if err != nil && err != unix.EINTR {
 				err_channel <- err
 				keep_going = false
 				return
diff --git a/tools/tui/loop/write.go b/tools/tui/loop/write.go
index 29b948f2d..cc24b3b64 100644
--- a/tools/tui/loop/write.go
+++ b/tools/tui/loop/write.go
@@ -8,6 +8,8 @@ import (
 	"os"
 	"time"
 
+	"golang.org/x/sys/unix"
+
 	"kitty/tools/tty"
 	"kitty/tools/utils"
 )
@@ -143,7 +145,7 @@ func write_to_tty(
 	wait_for_write_available := func() {
 		for {
 			n, err := selector.WaitForever()
-			if err != nil {
+			if err != nil && err != unix.EINTR {
 				err_channel <- err
 				keep_going = false
 				return
diff --git a/tools/utils/select.go b/tools/utils/select.go
index 8c52f217d..9d85bb87b 100644
--- a/tools/utils/select.go
+++ b/tools/utils/select.go
@@ -75,7 +75,7 @@ func (self *Selector) Wait(timeout time.Duration) (num_ready int, err error) {
 		self.read_set.Zero()
 		self.write_set.Zero()
 		self.err_set.Zero()
-		return 0, nil
+		return 0, err
 	}
 	return
 }