cosmos-sdk/store/cachekv/internal/memiterator.go

121 lines
2.0 KiB
Go

package internal
import (
"bytes"
"errors"
"github.com/tidwall/btree"
"cosmossdk.io/store/types"
)
var _ types.Iterator = (*memIterator)(nil)
// memIterator iterates over iterKVCache items.
// if value is nil, means it was deleted.
// Implements Iterator.
type memIterator struct {
iter btree.IterG[item]
start []byte
end []byte
ascending bool
valid bool
}
func newMemIterator(start, end []byte, items BTree, ascending bool) *memIterator {
iter := items.tree.Iter()
var valid bool
if ascending {
if start != nil {
valid = iter.Seek(newItem(start, nil))
} else {
valid = iter.First()
}
} else {
if end != nil {
valid = iter.Seek(newItem(end, nil))
if !valid {
valid = iter.Last()
} else {
// end is exclusive
valid = iter.Prev()
}
} else {
valid = iter.Last()
}
}
mi := &memIterator{
iter: iter,
start: start,
end: end,
ascending: ascending,
valid: valid,
}
if mi.valid {
mi.valid = mi.keyInRange(mi.Key())
}
return mi
}
func (mi *memIterator) Domain() (start, end []byte) {
return mi.start, mi.end
}
func (mi *memIterator) Close() error {
mi.iter.Release()
return nil
}
func (mi *memIterator) Error() error {
if !mi.Valid() {
return errors.New("invalid memIterator")
}
return nil
}
func (mi *memIterator) Valid() bool {
return mi.valid
}
func (mi *memIterator) Next() {
mi.assertValid()
if mi.ascending {
mi.valid = mi.iter.Next()
} else {
mi.valid = mi.iter.Prev()
}
if mi.valid {
mi.valid = mi.keyInRange(mi.Key())
}
}
func (mi *memIterator) keyInRange(key []byte) bool {
if mi.ascending && mi.end != nil && bytes.Compare(key, mi.end) >= 0 {
return false
}
if !mi.ascending && mi.start != nil && bytes.Compare(key, mi.start) < 0 {
return false
}
return true
}
func (mi *memIterator) Key() []byte {
return mi.iter.Item().key
}
func (mi *memIterator) Value() []byte {
return mi.iter.Item().value
}
func (mi *memIterator) assertValid() {
if err := mi.Error(); err != nil {
panic(err)
}
}