Implement previews for plain text files

tools/highlight/api.go

@@ -44,6 +44,7 @@ func NewSanitizeControlCodes(replace_tab_by string) *SanitizeControlCodes {
 
 type Highlighter interface {
 	HighlightFile(path string, srd StyleResolveData) (highlighted_string string, err error)
+	Sanitize(string) string
 }
 
 func NewHighlighter(sanitize func(string) string) Highlighter {

tools/highlight/impl.go

@@ -180,6 +180,8 @@ type highlighter struct {
 	sanitize   func(string) string
 }
 
+func (h *highlighter) Sanitize(x string) string { return h.sanitize(x) }
+
 func (h *highlighter) HighlightFile(path string, srd StyleResolveData) (highlighted_string string, err error) {
 	defer func() {
 		if r := recover(); r != nil {

tools/wcswidth/truncate.go

@@ -5,6 +5,7 @@ package wcswidth
 import (
 	"errors"
 	"fmt"
+	"io"
 	"strconv"
 
 	"github.com/kovidgoyal/kitty/tools/utils"
@@ -50,6 +51,17 @@ func (self *truncate_iterator) handle_st_terminated_escape_code(body []byte) err
 	return nil
 }
 
+func KeepOnlyCSI(text string, output io.Writer) {
+	var w WCWidthIterator
+	w.parser.HandleCSI = func(data []byte) (err error) {
+		_, err = output.Write([]byte{'\x1b', '['})
+		if err == nil {
+			_, err = output.Write(data)
+		}
+		return
+	}
+}
+
 func create_truncate_iterator() *truncate_iterator {
 	var ans truncate_iterator
 	ans.w.parser.HandleRune = ans.handle_rune