func (e print) do(ed *Editor, w io.Writer) (addr, error) {
at, err := e.a.where(ed)
if err != nil {
return addr{}, err
}
r := runes.LimitReader(ed.buf.runes.Reader(at.from), at.size())
if _, err := runes.Copy(runes.UTF8Writer(w), r); err != nil {
return addr{}, err
}
return at, nil
}
// Change changes the string identified by at
// to contain the runes from the Reader.
//
// This method must be called with the Lock held.
func (buf *Buffer) change(at addr, src runes.Reader) error {
if err := buf.runes.Delete(at.size(), at.from); err != nil {
return err
}
n, err := runes.Copy(buf.runes.Writer(at.from), src)
if err != nil {
return err
}
for _, ed := range buf.eds {
for m := range ed.marks {
ed.marks[m] = ed.marks[m].update(at, n)
}
}
return nil
}
func (l *log) append(seq int32, at addr, src runes.Reader) error {
prev := l.last
l.last = l.buf.Size()
n, err := runes.Copy(l.buf.Writer(l.last), src)
if err != nil {
return err
}
// Insert the header before the data.
h := header{
prev: prev,
at: at,
size: n,
seq: seq,
}
return l.buf.Insert(h.marshal(), l.last)
}