code review 12021044: container/list: added MoveBefore and MoveAfter

container/list: added MoveBefore and MoveAfter

Fixes issue 4940.

[peted, 2013-07-31 18:33:42]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://code.google.com/p/go

[bradfitz, 2013-07-31 19:44:19]

R=gri



On Wed, Jul 31, 2013 at 11:33 AM, <pieter@binky.org.uk> wrote:

> Reviewers: golang-dev1,
>
> Message:
> Hello golang-dev@googlegroups.com,
>
> I'd like you to review this change to
> https://code.google.com/p/go
>
>
> Description:
> container/list: added MoveBefore and MoveAfter
>
> Fixes issue 4940.
>
> Please review this at
https://codereview.appspot.**com/12021044/<https://codereview.appspot.com/120...
>
> Affected files:
>   M src/pkg/container/list/list.go
>   M src/pkg/container/list/list_**test.go
>
>
> Index: src/pkg/container/list/list.go
> ==============================**==============================**=======
> --- a/src/pkg/container/list/list.**go
> +++ b/src/pkg/container/list/list.**go
> @@ -179,6 +179,24 @@
>         l.insert(l.remove(e), l.root.prev)
>  }
>
> +// MoveBefore moves element e to its new position before mark.
> +// If e is not an element of l, or e == mark, the list is not modified.
> +func (l *List) MoveBefore(e, mark *Element) {
> +       if e.list != l || e == mark {
> +               return
> +       }
> +       l.insert(l.remove(e), mark.prev)
> +}
> +
> +// MoveAfter moves element e to its new position after mark.
> +// If e is not an element of l, or e == mark, the list is not modified.
> +func (l *List) MoveAfter(e, mark *Element) {
> +       if e.list != l || e == mark {
> +               return
> +       }
> +       l.insert(l.remove(e), mark)
> +}
> +
>  // PushBackList inserts a copy of an other list at the back of list l.
>  // The lists l and other may be the same.
>  func (l *List) PushBackList(other *List) {
> Index: src/pkg/container/list/list_**test.go
> ==============================**==============================**=======
> --- a/src/pkg/container/list/list_**test.go
> +++ b/src/pkg/container/list/list_**test.go
> @@ -233,3 +233,37 @@
>                 t.Errorf("l1.Len() = %d, want 3", n)
>         }
>  }
> +
> +func TestMove(t *testing.T) {
> +       l := New()
> +       e1 := l.PushBack(1)
> +       e2 := l.PushBack(2)
> +       e3 := l.PushBack(3)
> +       e4 := l.PushBack(4)
> +
> +       l.MoveAfter(e3, e3)
> +       checkListPointers(t, l, []*Element{e1, e2, e3, e4})
> +       l.MoveBefore(e2, e2)
> +       checkListPointers(t, l, []*Element{e1, e2, e3, e4})
> +
> +       l.MoveAfter(e3, e2)
> +       checkListPointers(t, l, []*Element{e1, e2, e3, e4})
> +       l.MoveBefore(e2, e3)
> +       checkListPointers(t, l, []*Element{e1, e2, e3, e4})
> +
> +       l.MoveBefore(e2, e4)
> +       checkListPointers(t, l, []*Element{e1, e3, e2, e4})
> +       e1, e2, e3, e4 = e1, e3, e2, e4
> +
> +       l.MoveBefore(e4, e1)
> +       checkListPointers(t, l, []*Element{e4, e1, e2, e3})
> +       e1, e2, e3, e4 = e4, e1, e2, e3
> +
> +       l.MoveAfter(e4, e1)
> +       checkListPointers(t, l, []*Element{e1, e4, e2, e3})
> +       e1, e2, e3, e4 = e1, e4, e2, e3
> +
> +       l.MoveAfter(e2, e3)
> +       checkListPointers(t, l, []*Element{e1, e3, e2, e4})
> +       e1, e2, e3, e4 = e1, e3, e2, e4
> +}
>
>
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[gri, 2013-07-31 20:39:13]

LGTM.
thanks.

[gri, 2013-07-31 21:11:28]

*** Submitted as https://code.google.com/p/go/source/detail?r=4cd1a99ee4de ***

container/list: added MoveBefore and MoveAfter

Fixes issue 4940.

R=golang-dev, bradfitz, gri
CC=golang-dev
https://codereview.appspot.com/12021044

Committer: Robert Griesemer <gri@golang.org>