// startReadLine prepares the terminal for the editor.
func (ed *Editor) startReadLine() error {
ed.activeMutex.Lock()
defer ed.activeMutex.Unlock()
ed.active = true
savedTermios, err := setupTerminal(ed.file)
if err != nil {
return err
}
ed.savedTermios = savedTermios
_, width := sys.GetWinsize(int(ed.file.Fd()))
// Turn on autowrap, write lackEOL along with enough padding to fill the
// whole screen. If the cursor was in the first column, we end up in the
// same line (just off the line boundary); otherwise we are now in the next
// line. We now rewind to the first column and erase anything there. The
// final effect is that a lackEOL gets written if and only if the cursor
// was not in the first column.
fmt.Fprintf(ed.file, "\033[?7h%s%*s\r \r", lackEOL, width-util.Wcwidth(lackEOLRune), "")
// Turn off autowrap. The edito has its own wrapping mechanism. Doing
// wrapping manually means that when the actual width of some characters
// are greater than what our wcwidth implementation tells us, characters at
// the end of that line gets hidden -- compared to pushed to the next line,
// which is more disastrous.
ed.file.WriteString("\033[?7l")
// Turn on SGR-style mouse tracking.
//ed.file.WriteString("\033[?1000;1006h")
// Enable bracketed paste.
ed.file.WriteString("\033[?2004h")
return nil
}
// write appends a single rune to a buffer.
func (b *buffer) write(r rune, style string) {
if r == '\n' {
b.newline()
return
} else if r < 0x20 || r == 0x7f {
// BUG(xiaq): buffer.write drops ASCII control characters silently
return
}
wd := util.Wcwidth(r)
c := cell{r, byte(wd), style}
if b.col+wd > b.width {
b.newline()
b.appendCell(c)
} else {
b.appendCell(c)
if b.col == b.width && b.newlineWhenFull {
b.newline()
}
}
}