Reset cumulative error counts on space

input.go

@@ -0,0 +1,48 @@
+package main
+
+import (
+	"os"
+
+	"golang.org/x/sys/unix"
+)
+
+// Delivers a value every time space is pressed. Puts the terminal in
+// non-canonical mode so the keypress arrives without waiting for a newline,
+// and returns a function that restores the original settings.
+func watchSpace() (<-chan struct{}, func()) {
+	ch := make(chan struct{}, 1)
+	restore := func() {}
+	fd := int(os.Stdin.Fd())
+
+	if orig, err := unix.IoctlGetTermios(fd, unix.TCGETS); err == nil {
+		saved := *orig
+		raw := *orig
+		raw.Lflag &^= unix.ICANON | unix.ECHO
+		raw.Cc[unix.VMIN] = 1
+		raw.Cc[unix.VTIME] = 0
+		if unix.IoctlSetTermios(fd, unix.TCSETS, &raw) == nil {
+			restore = func() { unix.IoctlSetTermios(fd, unix.TCSETS, &saved) }
+		}
+	}
+
+	go func() {
+		buf := make([]byte, 64)
+		for {
+			n, err := os.Stdin.Read(buf)
+			if err != nil {
+				return
+			}
+			for _, b := range buf[:n] {
+				if b != ' ' {
+					continue
+				}
+				select {
+				case ch <- struct{}{}:
+				default:
+				}
+			}
+		}
+	}()
+
+	return ch, restore
+}