From 67436a48cdebf23d08292704aa057ff1b4bd2713 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Tue, 14 Feb 2023 22:27:41 +0530
Subject: [PATCH] New API to suspend a loop

---
 tools/tty/tty.go      | 22 ++++++++++++++++------
 tools/tui/loop/api.go |  3 ++-
 tools/tui/loop/run.go | 23 +++++++++++++++++++++++
 3 files changed, 41 insertions(+), 7 deletions(-)

diff --git a/tools/tty/tty.go b/tools/tty/tty.go
index 1542a59f5..88391f361 100644
--- a/tools/tty/tty.go
+++ b/tools/tty/tty.go
@@ -209,20 +209,30 @@ func (self *Term) RestoreAndClose() error {
 	return self.Close()
 }
 
-func (self *Term) SuspendAndRun(callback func() error) error {
+func (self *Term) Suspend() (resume func() error, err error) {
 	var state unix.Termios
-	err := self.Tcgetattr(&state)
+	err = self.Tcgetattr(&state)
 	if err != nil {
-		return err
+		return nil, err
 	}
 	if len(self.states) > 0 {
 		err := self.Tcsetattr(TCSANOW, &self.states[0])
 		if err != nil {
-			return err
+			return nil, err
 		}
 	}
-	defer self.Tcsetattr(TCSANOW, &state)
-	return callback()
+	return func() error { return self.Tcsetattr(TCSANOW, &state) }, nil
+
+}
+
+func (self *Term) SuspendAndRun(callback func() error) error {
+	resume, err := self.Suspend()
+	if err != nil {
+		return err
+	}
+	err = callback()
+	resume()
+	return err
 }
 
 func clamp(v, lo, hi int64) int64 {
diff --git a/tools/tui/loop/api.go b/tools/tui/loop/api.go
index ecef2ef01..040f9eacc 100644
--- a/tools/tui/loop/api.go
+++ b/tools/tui/loop/api.go
@@ -58,7 +58,8 @@ type Loop struct {
 	pending_writes                         []*write_msg
 	on_SIGTSTP                             func() error
 
-	// Send strings to this channel to queue writes in a thread safe way
+	// Suspend the loop restoring terminal state. Call the return resume function to restore the loop
+	Suspend func() (func() error, error)
 
 	// Callbacks
 
diff --git a/tools/tui/loop/run.go b/tools/tui/loop/run.go
index d0dfd91da..4832c4f07 100644
--- a/tools/tui/loop/run.go
+++ b/tools/tui/loop/run.go
@@ -290,6 +290,29 @@ func (self *Loop) run() (err error) {
 		}
 	}
 
+	self.Suspend = func() (func() error, error) {
+		write_id := self.QueueWriteString(self.terminal_options.ResetStateEscapeCodes())
+		needs_reset_escape_codes = false
+		err := self.wait_for_write_to_complete(write_id, tty_write_channel, write_done_channel, 2*time.Second)
+		if err != nil {
+			return nil, err
+		}
+		resume, err := controlling_term.Suspend()
+		if err != nil {
+			return nil, err
+		}
+		return func() (err error) {
+			err = resume()
+			if err != nil {
+				return
+			}
+			write_id = self.QueueWriteString(self.terminal_options.SetStateEscapeCodes())
+			needs_reset_escape_codes = true
+			return self.wait_for_write_to_complete(write_id, tty_write_channel, write_done_channel, 2*time.Second)
+		}, nil
+
+	}
+
 	self.on_SIGTSTP = func() error {
 		write_id := self.QueueWriteString(self.terminal_options.ResetStateEscapeCodes())
 		needs_reset_escape_codes = false