aminal/terminal/csi.go

package terminal

import (
	"fmt"
	"strconv"
	"strings"
)

var csiSequenceMap = map[rune]csiSequenceHandler{
	'm': sgrSequenceHandler,
	'P': csiDeleteHandler,
	'J': csiEraseInDisplayHandler,
	'K': csiEraseInLineHandler,
}

type csiSequenceHandler func(params []string, intermediate string, terminal *Terminal) error

// CSI: Control Sequence Introducer [
func csiHandler(buffer chan rune, terminal *Terminal) error {
	var final rune
	var b rune
	var err error
	param := ""
	intermediate := ""
CSI:
	for {
		b = <-buffer
		switch true {
		case b >= 0x30 && b <= 0x3F:
			param = param + string(b)
		case b >= 0x20 && b <= 0x2F:
			//intermediate? useful?
			intermediate += string(b)
		case b >= 0x40 && b <= 0x7e:
			final = b
			break CSI
		}
	}

	params := strings.Split(param, ";")

	handler, ok := csiSequenceMap[final]
	if ok {
		err = handler(params, intermediate, terminal)
	} else {

		switch final {
		case 'A':
			distance := 1
			if len(params) > 0 {
				var err error
				distance, err = strconv.Atoi(params[0])
				if err != nil {
					distance = 1
				}
			}
			terminal.buffer.MovePosition(0, -int16(distance))
		case 'B':
			distance := 1
			if len(params) > 0 {
				var err error
				distance, err = strconv.Atoi(params[0])
				if err != nil {
					distance = 1
				}
			}

			terminal.buffer.MovePosition(0, int16(distance))
		case 'C':

			distance := 1
			if len(params) > 0 {
				var err error
				distance, err = strconv.Atoi(params[0])
				if err != nil {
					distance = 1
				}
			}

			terminal.buffer.MovePosition(int16(distance), 0)

		case 'D':

			distance := 1
			if len(params) > 0 {
				var err error
				distance, err = strconv.Atoi(params[0])
				if err != nil {
					distance = 1
				}
			}

			terminal.buffer.MovePosition(-int16(distance), 0)

		case 'E':
			distance := 1
			if len(params) > 0 {
				var err error
				distance, err = strconv.Atoi(params[0])
				if err != nil {
					distance = 1
				}
			}

			terminal.buffer.MovePosition(0, int16(distance))
			terminal.buffer.SetPosition(0, terminal.buffer.CursorLine())

		case 'F':

			distance := 1
			if len(params) > 0 {
				var err error
				distance, err = strconv.Atoi(params[0])
				if err != nil {
					distance = 1
				}
			}
			terminal.buffer.MovePosition(0, -int16(distance))
			terminal.buffer.SetPosition(0, terminal.buffer.CursorLine())

		case 'G':

			distance := 1
			if len(params) > 0 {
				var err error
				distance, err = strconv.Atoi(params[0])
				if err != nil || params[0] == "" {
					distance = 1
				}
			}

			terminal.buffer.SetPosition(uint16(distance-1), terminal.buffer.CursorLine())

		case 'H', 'f':

			x, y := 1, 1
			if len(params) == 2 {
				var err error
				if params[0] != "" {
					y, err = strconv.Atoi(string(params[0]))
					if err != nil {
						y = 1
					}
				}
				if params[1] != "" {
					x, err = strconv.Atoi(string(params[1]))
					if err != nil {
						x = 1
					}
				}
			}

			terminal.buffer.SetPosition(uint16(x-1), uint16(y-1))

		default:
			switch param + intermediate + string(final) {
			case "?25h":
				terminal.buffer.ShowCursor()
			case "?25l":
				terminal.buffer.HideCursor()
			case "?12h":
				terminal.buffer.SetCursorBlink(true)
			case "?12l":
				terminal.buffer.SetCursorBlink(false)
			default:
				err = fmt.Errorf("Unknown CSI control sequence: 0x%02X (ESC[%s%s%s)", final, param, intermediate, string(final))
			}

		}
	}
	terminal.logger.Debugf("Received CSI control sequence: 0x%02X (ESC[%s%s%s)", final, param, intermediate, string(final))
	return err
}

func csiDeleteHandler(params []string, intermediate string, terminal *Terminal) error {
	n := 1
	if len(params) >= 1 {
		var err error
		n, err = strconv.Atoi(params[0])
		if err != nil {
			n = 1
		}
	}
	_ = n
	return nil
}

// CSI Ps J
func csiEraseInDisplayHandler(params []string, intermediate string, terminal *Terminal) error {
	n := "0"
	if len(params) > 0 {
		n = params[0]
	}

	switch n {

	case "0", "":
		terminal.buffer.EraseDisplayFromCursor()
	case "1":
		terminal.buffer.EraseDisplayToCursor()
	case "2":
		terminal.buffer.EraseDisplay()
	default:
		return fmt.Errorf("Unsupported ED: CSI %s J", n)
	}

	return nil
}

// CSI Ps K
func csiEraseInLineHandler(params []string, intermediate string, terminal *Terminal) error {

	n := "0"
	if len(params) > 0 {
		n = params[0]
	}

	switch n {
	case "0", "": //erase adter cursor
		terminal.buffer.EraseLineFromCursor()
	case "1": // erase to cursor inclusive
		terminal.buffer.EraseLineToCursor()
	case "2": // erase entire
		terminal.buffer.EraseLine()
	default:
		return fmt.Errorf("Unsupported EL: CSI %s K", n)
	}
	return nil
}