ceremonyclient/pebble/internal/arenaskl/flush_iterator.go
Cassandra Heart 2e2a1e4789
v1.2.0 (#31)
2024-01-03 01:31:42 -06:00

89 lines
2.9 KiB
Go

/*
* Copyright 2017 Dgraph Labs, Inc. and Contributors
* Modifications copyright (C) 2017 Andy Kimball and Contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package arenaskl
import "github.com/cockroachdb/pebble/internal/base"
// flushIterator is an iterator over the skiplist object. Use Skiplist.NewFlushIter
// to construct an iterator. The current state of the iterator can be cloned by
// simply value copying the struct.
type flushIterator struct {
Iterator
bytesIterated *uint64
}
// flushIterator implements the base.InternalIterator interface.
var _ base.InternalIterator = (*flushIterator)(nil)
func (it *flushIterator) String() string {
return "memtable"
}
func (it *flushIterator) SeekGE(
key []byte, flags base.SeekGEFlags,
) (*base.InternalKey, base.LazyValue) {
panic("pebble: SeekGE unimplemented")
}
func (it *flushIterator) SeekPrefixGE(
prefix, key []byte, flags base.SeekGEFlags,
) (*base.InternalKey, base.LazyValue) {
panic("pebble: SeekPrefixGE unimplemented")
}
func (it *flushIterator) SeekLT(
key []byte, flags base.SeekLTFlags,
) (*base.InternalKey, base.LazyValue) {
panic("pebble: SeekLT unimplemented")
}
// First seeks position at the first entry in list. Returns the key and value
// if the iterator is pointing at a valid entry, and (nil, nil) otherwise. Note
// that First only checks the upper bound. It is up to the caller to ensure
// that key is greater than or equal to the lower bound.
func (it *flushIterator) First() (*base.InternalKey, base.LazyValue) {
key, val := it.Iterator.First()
if key == nil {
return nil, base.LazyValue{}
}
*it.bytesIterated += uint64(it.nd.allocSize)
return key, val
}
// Next advances to the next position. Returns the key and value if the
// iterator is pointing at a valid entry, and (nil, nil) otherwise.
// Note: flushIterator.Next mirrors the implementation of Iterator.Next
// due to performance. Keep the two in sync.
func (it *flushIterator) Next() (*base.InternalKey, base.LazyValue) {
it.nd = it.list.getNext(it.nd, 0)
if it.nd == it.list.tail {
return nil, base.LazyValue{}
}
it.decodeKey()
*it.bytesIterated += uint64(it.nd.allocSize)
return &it.key, base.MakeInPlaceValue(it.value())
}
func (it *flushIterator) NextPrefix(succKey []byte) (*base.InternalKey, base.LazyValue) {
panic("pebble: NextPrefix unimplemented")
}
func (it *flushIterator) Prev() (*base.InternalKey, base.LazyValue) {
panic("pebble: Prev unimplemented")
}