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selected_child_iterator.go
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/
selected_child_iterator.go
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package dagtraversalmanager
import (
"github.com/kaspanet/kaspad/domain/consensus/model"
"github.com/kaspanet/kaspad/domain/consensus/model/externalapi"
"github.com/pkg/errors"
)
type selectedChildIterator struct {
dagTraversalManager model.DAGTraversalManager
includeLowHash bool
highHash, lowHash *externalapi.DomainHash
current *externalapi.DomainHash
err error
isClosed bool
stagingArea *model.StagingArea
}
func (s *selectedChildIterator) First() bool {
if s.isClosed {
panic("Tried using a closed SelectedChildIterator")
}
s.current = s.lowHash
if s.includeLowHash {
return true
}
return s.Next()
}
func (s *selectedChildIterator) Next() bool {
if s.isClosed {
panic("Tried using a closed SelectedChildIterator")
}
if s.err != nil {
return true
}
selectedChild, err := s.dagTraversalManager.SelectedChild(s.stagingArea, s.highHash, s.current)
if errors.Is(err, errNoSelectedChild) {
return false
}
if err != nil {
s.current = nil
s.err = err
return true
}
s.current = selectedChild
return true
}
func (s *selectedChildIterator) Get() (*externalapi.DomainHash, error) {
if s.isClosed {
return nil, errors.New("Tried using a closed SelectedChildIterator")
}
return s.current, s.err
}
func (s *selectedChildIterator) Close() error {
if s.isClosed {
return errors.New("Tried using a closed SelectedChildIterator")
}
s.isClosed = true
s.highHash = nil
s.lowHash = nil
s.current = nil
s.err = nil
return nil
}
// SelectedChildIterator returns a BlockIterator that iterates from lowHash (exclusive) to highHash (inclusive) over
// highHash's selected parent chain
func (dtm *dagTraversalManager) SelectedChildIterator(stagingArea *model.StagingArea,
highHash, lowHash *externalapi.DomainHash, includeLowHash bool) (model.BlockIterator, error) {
isLowHashInSelectedParentChainOfHighHash, err := dtm.dagTopologyManager.IsInSelectedParentChainOf(
stagingArea, lowHash, highHash)
if err != nil {
return nil, err
}
if !isLowHashInSelectedParentChainOfHighHash {
return nil, errors.Errorf("%s is not in the selected parent chain of %s", highHash, lowHash)
}
return &selectedChildIterator{
dagTraversalManager: dtm,
includeLowHash: includeLowHash,
highHash: highHash,
lowHash: lowHash,
current: lowHash,
stagingArea: stagingArea,
}, nil
}
var errNoSelectedChild = errors.New("errNoSelectedChild")
func (dtm *dagTraversalManager) SelectedChild(stagingArea *model.StagingArea,
context, blockHash *externalapi.DomainHash) (*externalapi.DomainHash, error) {
data, err := dtm.reachabilityDataStore.ReachabilityData(dtm.databaseContext, stagingArea, blockHash)
if err != nil {
return nil, err
}
for _, child := range data.Children() {
isChildInSelectedParentChainOfHighHash, err := dtm.dagTopologyManager.IsInSelectedParentChainOf(
stagingArea, child, context)
if err != nil {
return nil, err
}
if isChildInSelectedParentChainOfHighHash {
return child, nil
}
}
return nil, errors.Wrapf(errNoSelectedChild, "no selected child for %s from the point of view of %s",
blockHash, context)
}