func (e move) do(ed *Editor, _ io.Writer) (addr, error) {
s, err := e.src.where(ed)
if err != nil {
return addr{}, err
}
d, err := e.dst.where(ed)
if err != nil {
return addr{}, err
}
d.from = d.to
if d.from > s.from && d.from < s.to {
return addr{}, errors.New("addresses overlap")
}
if d.from >= s.to {
// Moving to after the source. Delete the source first.
if err := pend(ed, s, runes.EmptyReader()); err != nil {
return addr{}, err
}
}
r := runes.LimitReader(ed.buf.runes.Reader(s.from), s.size())
if err := pend(ed, d, r); err != nil {
return addr{}, err
}
if d.from <= s.from {
// Moving to before the source. Delete the source second.
if err := pend(ed, s, runes.EmptyReader()); err != nil {
return addr{}, err
}
}
return d, nil
}
func TestEditorDoOutOfSequence(t *testing.T) {
ed := NewEditor(NewBuffer())
defer ed.buf.Close()
const init = "Hello, 世界"
if err := ed.change(All, init); err != nil {
t.Fatalf("failed to init: %v", err)
}
maddr := addr{5, 10}
ed.marks['m'] = maddr
err := ed.do(func() (addr, error) {
if err := pend(ed, addr{10, 20}, runes.EmptyReader()); err != nil {
panic(err)
}
if err := pend(ed, addr{0, 10}, runes.EmptyReader()); err != nil {
panic(err)
}
return addr{0, 20}, nil
})
if err == nil {
t.Error("ed.do({out-of-sequence})=<nil>, want error")
}
if ed.marks['m'] != maddr {
t.Errorf("ed.marks['m']=%v, want %v", ed.marks['m'], maddr)
}
}