fix: Save and close taking time when Flex or Icom is not connected

internal/cat/flex.go

@@ -4,6 +4,7 @@ package cat
 
 import (
 	"bufio"
+	"context"
 	"encoding/binary"
 	"fmt"
 	"math"
@@ -25,9 +26,10 @@ type Flex struct {
 	host string
 	port int
 
-	mu        sync.Mutex
-	conn      net.Conn
-	wmu       sync.Mutex // serialises writes to conn
+	mu         sync.Mutex
+	conn       net.Conn
+	dialCancel context.CancelFunc // cancels an in-flight Connect dial (Interrupt/Stop); nil when not dialing
+	wmu        sync.Mutex         // serialises writes to conn
 	seq       int
 	handle    string
 	model     string
@@ -171,7 +173,19 @@ func (f *Flex) Connect() error {
 	if host == "" {
 		return fmt.Errorf("flex: no radio IP configured")
 	}
-	conn, err := net.DialTimeout("tcp", net.JoinHostPort(host, strconv.Itoa(port)), 5*time.Second)
+	// Cancellable dial: Interrupt() (called by Stop/Start) aborts it at once so a
+	// dead radio's 5 s dial timeout doesn't make Stop / Settings "Save & Close"
+	// wait several seconds for the poll goroutine to give up.
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	f.mu.Lock()
+	f.dialCancel = cancel
+	f.mu.Unlock()
+	var d net.Dialer
+	conn, err := d.DialContext(ctx, "tcp", net.JoinHostPort(host, strconv.Itoa(port)))
+	cancel()
+	f.mu.Lock()
+	f.dialCancel = nil
+	f.mu.Unlock()
 	if err != nil {
 		return fmt.Errorf("flex: connect %s:%d: %w", host, port, err)
 	}
@@ -224,6 +238,23 @@ func (f *Flex) Disconnect() {
 	}
 }
 
+// Interrupt aborts an in-flight Connect dial so Stop()/Start() (Settings
+// "Save & Close", CAT backend switch) don't block on a dead radio's 5 s dial
+// timeout. Satisfies the Manager's optional interruptible interface. Safe to call
+// anytime and from another goroutine; a no-op when not dialing.
+func (f *Flex) Interrupt() {
+	f.mu.Lock()
+	cancel := f.dialCancel
+	c := f.conn
+	f.mu.Unlock()
+	if cancel != nil {
+		cancel()
+	}
+	if c != nil {
+		_ = c.Close() // unblock the reader if we're already past the dial
+	}
+}
+
 // send writes a sequenced command (C<seq>|<cmd>) to the radio and returns the
 // sequence number (so the caller can match the R<seq> response, e.g. to learn a
 // new spot's index). Returns 0 when not connected. Best effort.

internal/cat/icomserial.go

@@ -444,8 +444,14 @@ func (b *IcomSerial) write(payload ...byte) error {
 
 // recv waits for a frame the reader routed to respCh that satisfies match, or
 // times out. The reader has already discarded echoes and split off scope frames,
-// so recv only ever sees candidate control replies.
+// so recv only ever sees candidate control replies. It also bails out at once if
+// Interrupt() fires (Stop) so an in-flight ReadState — which can be a dozen reads,
+// each up to icomReadTimeout when the rig is slow — doesn't make Stop/Save-&-Close
+// wait several seconds for the poll goroutine to finish.
 func (b *IcomSerial) recv(timeout time.Duration, match func(civ.Decoded) bool) (civ.Decoded, error) {
+	b.dialMu.Lock()
+	cancel := b.dialCancel
+	b.dialMu.Unlock()
 	deadline := time.After(timeout)
 	for {
 		select {
@@ -453,6 +459,8 @@ func (b *IcomSerial) recv(timeout time.Duration, match func(civ.Decoded) bool) (
 			if match(f) {
 				return f, nil
 			}
+		case <-cancel:
+			return civ.Decoded{}, fmt.Errorf("icom: interrupted")
 		case <-deadline:
 			return civ.Decoded{}, fmt.Errorf("icom: timeout waiting for response")
 		}

internal/cat/tci.go

@@ -3,6 +3,7 @@
 package cat
 
 import (
+	"context"
 	"fmt"
 	"net"
 	"strconv"
@@ -27,9 +28,10 @@ type TCI struct {
 	digitalDefault string // surfaced when the rig reports a digital mode (FT8/…)
 	spotsEnabled   bool   // mirror cluster spots onto the TCI panorama
 
-	mu    sync.Mutex // guards conn + writes + state
-	conn  *websocket.Conn
-	ready bool
+	mu         sync.Mutex // guards conn + writes + state
+	conn       *websocket.Conn
+	dialCancel context.CancelFunc // cancels an in-flight Connect dial (Interrupt/Stop)
+	ready      bool
 
 	// Cached state pushed by the radio.
 	device string
@@ -70,8 +72,18 @@ func (t *TCI) Connect() error {
 		return fmt.Errorf("tci: no host configured")
 	}
 	url := fmt.Sprintf("ws://%s", net.JoinHostPort(host, strconv.Itoa(port)))
+	// Cancellable dial so Interrupt() (Stop / Settings "Save & Close") aborts it at
+	// once instead of waiting out a dead server's 5 s handshake timeout.
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	t.mu.Lock()
+	t.dialCancel = cancel
+	t.mu.Unlock()
 	dialer := websocket.Dialer{HandshakeTimeout: 5 * time.Second}
-	conn, _, err := dialer.Dial(url, nil)
+	conn, _, err := dialer.DialContext(ctx, url, nil)
+	cancel()
+	t.mu.Lock()
+	t.dialCancel = nil
+	t.mu.Unlock()
 	if err != nil {
 		return fmt.Errorf("tci: connect %s: %w", url, err)
 	}
@@ -122,6 +134,22 @@ func (t *TCI) Disconnect() {
 	}
 }
 
+// Interrupt aborts an in-flight Connect dial so Stop()/Start() don't block on a
+// dead server's handshake timeout. Satisfies the Manager's interruptible
+// interface. Safe from another goroutine; a no-op when not dialing.
+func (t *TCI) Interrupt() {
+	t.mu.Lock()
+	cancel := t.dialCancel
+	c := t.conn
+	t.mu.Unlock()
+	if cancel != nil {
+		cancel()
+	}
+	if c != nil {
+		_ = c.Close()
+	}
+}
+
 // ReadState returns the cached state pushed by the radio.
 func (t *TCI) ReadState() (RigState, error) {
 	t.mu.Lock()