Fantom-foundation/go-lachesis

package poset

import (
    "errors"

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

type eventFilterFn func(event *inter.EventHeaderData) bool

// dfsSubgraph iterates all the events which are observed by head, and accepted by a filter.
// filter MAY BE called twice for the same event.
func (p *Poset) dfsSubgraph(head hash.Event, filter eventFilterFn) error {
    stack := make(hash.EventsStack, 0, p.Validators.Len()*10)

    for pwalk := &head; pwalk != nil; pwalk = stack.Pop() {
        walk := *pwalk

        event := p.input.GetEventHeader(p.EpochN, walk)
        if event == nil {
            return errors.New("event not found " + walk.String())
        }

        // filter
        if !filter(event) {
            continue
        }

        // memorize parents
        for _, parent := range event.Parents {
            stack.Push(parent)
        }
    }

    return nil
}