Method LREM

lists.go:604–653

LREM removes the first occurrence on the given side of the given element.

(key string, side LSide, element Value)

// LREM removes the first occurrence on the given side of the given element.
func (c Client) LREM(key string, side LSide, element Value) (newLength int64, done bool, err error) {
	var actions []dynamodb.TransactWriteItem

	outgoingNode, found, err := c.listNodeAtPivot(key, element, side)
	if err != nil || !found {
		return newLength, false, err
	}

	switch {
	case outgoingNode.isHead():
		_, done, err = c.listPop(key, Left)
	case outgoingNode.isTail():
		_, done, err = c.listPop(key, Right)
	default:
		leftKeyNode, found, err := c.listGetByAddress(key, outgoingNode.left)
		if !found || err != nil {
			return newLength, false, err
		}

		rightKeyNode, found, err := c.listGetByAddress(key, outgoingNode.right)

		if !found || err != nil {
			return newLength, false, err
		}

		actions = append(actions, leftKeyNode.updateSideAction(Right, rightKeyNode.address, c))
		actions = append(actions, rightKeyNode.updateSideAction(Left, leftKeyNode.address, c))
		actions = append(actions, outgoingNode.deleteAction(c))
		actions = append(actions, c.listCountDeltaAction(key, -1))
	}

	if err != nil {
		return newLength, done, err
	}

	if len(actions) > 0 {
		_, err = c.ddbClient.TransactWriteItemsRequest(&dynamodb.TransactWriteItemsInput{
			TransactItems: actions,
		}).Send(context.TODO())
		if err != nil {
			return newLength, done, err
		}

		done = true
	}

	newLength, err = c.LLEN(key)

	return newLength, done, err
}

func (c Client) LSET(key string, index int64, element string) (ok bool, err error) {
	node, found, err := c.listNodeAtIndex(key, index)