Refactor loop code into its own package

tools/tui/loop/read.go

@@ -0,0 +1,99 @@
+// License: GPLv3 Copyright: 2022, Kovid Goyal, <kovid at kovidgoyal.net>
+
+package loop
+
+import (
+	"io"
+	"os"
+
+	"golang.org/x/sys/unix"
+
+	"kitty/tools/tty"
+	"kitty/tools/utils"
+)
+
+func (self *Loop) dispatch_input_data(data []byte) error {
+	if self.OnReceivedData != nil {
+		err := self.OnReceivedData(data)
+		if err != nil {
+			return err
+		}
+	}
+	err := self.escape_code_parser.Parse(data)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func read_ignoring_temporary_errors(f *tty.Term, buf []byte) (int, error) {
+	n, err := f.Read(buf)
+	if err == unix.EINTR || err == unix.EAGAIN || err == unix.EWOULDBLOCK {
+		return 0, nil
+	}
+	if n == 0 {
+		return 0, io.EOF
+	}
+	return n, err
+}
+
+func read_from_tty(pipe_r *os.File, term *tty.Term, results_channel chan<- []byte, err_channel chan<- error, quit_channel <-chan byte) {
+	keep_going := true
+	pipe_fd := int(pipe_r.Fd())
+	tty_fd := term.Fd()
+	selector := utils.CreateSelect(2)
+	selector.RegisterRead(pipe_fd)
+	selector.RegisterRead(tty_fd)
+
+	defer func() {
+		close(results_channel)
+		pipe_r.Close()
+	}()
+
+	const bufsize = 2 * utils.DEFAULT_IO_BUFFER_SIZE
+
+	wait_for_read_available := func() {
+		_, err := selector.WaitForever()
+		if err != nil {
+			err_channel <- err
+			keep_going = false
+			return
+		}
+		if selector.IsReadyToRead(pipe_fd) {
+			keep_going = false
+			return
+		}
+		if selector.IsReadyToRead(tty_fd) {
+			return
+		}
+	}
+
+	buf := make([]byte, bufsize)
+	for keep_going {
+		if len(buf) == 0 {
+			buf = make([]byte, bufsize)
+		}
+		if wait_for_read_available(); !keep_going {
+			break
+		}
+		n, err := read_ignoring_temporary_errors(term, buf)
+		if err != nil {
+			err_channel <- err
+			keep_going = false
+			break
+		}
+		if n == 0 {
+			err_channel <- io.EOF
+			keep_going = false
+			break
+		}
+		send := buf[:n]
+		buf = buf[n:]
+		select {
+		case results_channel <- send:
+		case <-quit_channel:
+			keep_going = false
+			break
+		}
+	}
+}