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tree_iterator.go
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tree_iterator.go
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// Copyright (C) 2019-2023, Ava Labs, Inc. All rights reserved.
// See the file LICENSE for licensing terms.
package state
import (
"sync"
"github.com/google/btree"
)
const defaultTreeDegree = 2
var _ StakerIterator = (*treeIterator)(nil)
type treeIterator struct {
current *Staker
next chan *Staker
releaseOnce sync.Once
release chan struct{}
wg sync.WaitGroup
}
// NewTreeIterator returns a new iterator of the stakers in [tree] in ascending
// order. Note that it isn't safe to modify [tree] while iterating over it.
func NewTreeIterator(tree *btree.BTreeG[*Staker]) StakerIterator {
if tree == nil {
return EmptyIterator
}
it := &treeIterator{
next: make(chan *Staker),
release: make(chan struct{}),
}
it.wg.Add(1)
go func() {
defer it.wg.Done()
tree.Ascend(func(i *Staker) bool {
select {
case it.next <- i:
return true
case <-it.release:
return false
}
})
close(it.next)
}()
return it
}
func (i *treeIterator) Next() bool {
next, ok := <-i.next
i.current = next
return ok
}
func (i *treeIterator) Value() *Staker {
return i.current
}
func (i *treeIterator) Release() {
i.releaseOnce.Do(func() {
close(i.release)
})
i.wg.Wait()
}