Proceed with defaults if no OSC response arrives within 5 seconds

termenv_unix.go

@@ -8,10 +8,16 @@ import (
 	"os"
 	"strconv"
 	"strings"
+	"time"
 
 	"golang.org/x/sys/unix"
 )
 
+const (
+	// timeout for OSC queries
+	OSCTimeout = 5 * time.Second
+)
+
 func colorProfile() Profile {
 	term := os.Getenv("TERM")
 	colorTerm := os.Getenv("COLORTERM")
@@ -84,7 +90,34 @@ func backgroundColor() Color {
 	return ANSIColor(0)
 }
 
+func waitForData(fd uintptr, timeout time.Duration) error {
+	tv := unix.NsecToTimeval(int64(timeout))
+	var readfds unix.FdSet
+	readfds.Set(int(fd))
+
+	for {
+		n, err := unix.Select(int(fd)+1, &readfds, nil, nil, &tv)
+		if err == unix.EINTR {
+			continue
+		}
+		if err != nil {
+			return err
+		}
+		if n == 0 {
+			return fmt.Errorf("timeout")
+		}
+
+		break
+	}
+
+	return nil
+}
+
 func readNextByte(f *os.File) (byte, error) {
+	if err := waitForData(f.Fd(), OSCTimeout); err != nil {
+		return 0, err
+	}
+
 	var b [1]byte
 	n, err := f.Read(b[:])
 	if err != nil {
@@ -107,20 +140,14 @@ func readNextResponse(fd *os.File) (response string, isOSC bool, err error) {
 		return "", false, err
 	}
 
-	// if we encounter a backslash, this is a left-over from the previous OSC
-	// response, which can be terminated by an optional backslash
-	if start == '\\' {
+	// first byte must be ESC
+	for start != '\033' {
 		start, err = readNextByte(fd)
 		if err != nil {
 			return "", false, err
 		}
 	}
 
-	// first byte must be ESC
-	if start != '\033' {
-		return "", false, ErrStatusReport
-	}
-
 	response += string(start)
 
 	// next byte is either '[' (cursor position response) or ']' (OSC response)