83 lines
2.4 KiB
Go
83 lines
2.4 KiB
Go
package wtclient
|
|
|
|
import (
|
|
"container/list"
|
|
"sync"
|
|
|
|
"github.com/lightningnetwork/lnd/watchtower/wtdb"
|
|
)
|
|
|
|
// TowerCandidateIterator provides an abstraction for iterating through possible
|
|
// watchtower addresses when attempting to create a new session.
|
|
type TowerCandidateIterator interface {
|
|
// Reset clears any internal iterator state, making previously taken
|
|
// candidates available as long as they remain in the set.
|
|
Reset() error
|
|
|
|
// Next returns the next candidate tower. The iterator is not required
|
|
// to return results in any particular order. If no more candidates are
|
|
// available, ErrTowerCandidatesExhausted is returned.
|
|
Next() (*wtdb.Tower, error)
|
|
}
|
|
|
|
// towerListIterator is a linked-list backed TowerCandidateIterator.
|
|
type towerListIterator struct {
|
|
mu sync.Mutex
|
|
candidates *list.List
|
|
nextCandidate *list.Element
|
|
}
|
|
|
|
// Compile-time constraint to ensure *towerListIterator implements the
|
|
// TowerCandidateIterator interface.
|
|
var _ TowerCandidateIterator = (*towerListIterator)(nil)
|
|
|
|
// newTowerListIterator initializes a new towerListIterator from a variadic list
|
|
// of lnwire.NetAddresses.
|
|
func newTowerListIterator(candidates ...*wtdb.Tower) *towerListIterator {
|
|
iter := &towerListIterator{
|
|
candidates: list.New(),
|
|
}
|
|
|
|
for _, candidate := range candidates {
|
|
iter.candidates.PushBack(candidate)
|
|
}
|
|
iter.Reset()
|
|
|
|
return iter
|
|
}
|
|
|
|
// Reset clears the iterators state, and makes the address at the front of the
|
|
// list the next item to be returned..
|
|
func (t *towerListIterator) Reset() error {
|
|
t.mu.Lock()
|
|
defer t.mu.Unlock()
|
|
|
|
// Reset the next candidate to the front of the linked-list.
|
|
t.nextCandidate = t.candidates.Front()
|
|
|
|
return nil
|
|
}
|
|
|
|
// Next returns the next candidate tower. This iterator will always return
|
|
// candidates in the order given when the iterator was instantiated. If no more
|
|
// candidates are available, ErrTowerCandidatesExhausted is returned.
|
|
func (t *towerListIterator) Next() (*wtdb.Tower, error) {
|
|
t.mu.Lock()
|
|
defer t.mu.Unlock()
|
|
|
|
// If the next candidate is nil, we've exhausted the list.
|
|
if t.nextCandidate == nil {
|
|
return nil, ErrTowerCandidatesExhausted
|
|
}
|
|
|
|
// Propose the tower at the front of the list.
|
|
tower := t.nextCandidate.Value.(*wtdb.Tower)
|
|
|
|
// Set the next candidate to the subsequent element.
|
|
t.nextCandidate = t.nextCandidate.Next()
|
|
|
|
return tower, nil
|
|
}
|
|
|
|
// TODO(conner): implement graph-backed candidate iterator for public towers.
|