Fantom-foundation/go-lachesis

package vector

import (
    "errors"

    "github.com/Fantom-foundation/go-lachesis/hash"
    "github.com/Fantom-foundation/go-lachesis/inter"
)

// dfsSubgraph iterates all the event which are observed by head, and accepted by a filter
// Excluding head
// filter MAY BE called twice for the same event.
func (vi *Index) dfsSubgraph(head *inter.EventHeaderData, walk func(hash.Event) (godeeper bool)) error {
    stack := make(hash.EventsStack, 0, vi.validators.Len()*5)

    // first element
    stack.PushAll(head.Parents)

    for next := stack.Pop(); next != nil; next = stack.Pop() {
        curr := *next

        // filter
        if !walk(curr) {
            continue
        }

        event := vi.getEvent(curr)
        if event == nil {
            return errors.New("event not found " + curr.String())
        }

        // memorize parents
        stack.PushAll(event.Parents)
    }

    return nil
}