62e6f1f648
In this commit, I saw that there was a simple incrementBytes() implementation elsewhere in bleve that seemed simpler than using the big int package. Edge case note: if the input bytes would overflow in incrementBytes(), such as with an input of [0xff 0xff 0xff], it returns nil. moss then treats a nil endKeyExclusive iterator param as a logical "higher-than-topmost" key, which produces the prefix iteration behavior that we want for this edge situation.
98 lines
1.9 KiB
Go
98 lines
1.9 KiB
Go
// Copyright (c) 2016 Couchbase, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package moss
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import (
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"github.com/couchbase/moss"
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"github.com/blevesearch/bleve/index/store"
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)
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type Reader struct {
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store *Store
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ss moss.Snapshot
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}
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func (r *Reader) Get(k []byte) (v []byte, err error) {
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v, err = r.ss.Get(k, moss.ReadOptions{})
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if err != nil {
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return nil, err
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}
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if v != nil {
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return append(make([]byte, 0, len(v)), v...), nil
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}
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return nil, nil
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}
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func (r *Reader) MultiGet(keys [][]byte) ([][]byte, error) {
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return store.MultiGet(r, keys)
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}
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func (r *Reader) PrefixIterator(k []byte) store.KVIterator {
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kEnd := incrementBytes(k)
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iter, err := r.ss.StartIterator(k, kEnd, moss.IteratorOptions{})
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if err != nil {
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return nil
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}
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rv := &Iterator{
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store: r.store,
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ss: r.ss,
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iter: iter,
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start: k,
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end: kEnd,
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}
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rv.current()
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return rv
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}
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func (r *Reader) RangeIterator(start, end []byte) store.KVIterator {
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iter, err := r.ss.StartIterator(start, end, moss.IteratorOptions{})
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if err != nil {
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return nil
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}
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rv := &Iterator{
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store: r.store,
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ss: r.ss,
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iter: iter,
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start: start,
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end: end,
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}
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rv.current()
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return rv
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}
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func (r *Reader) Close() error {
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return r.ss.Close()
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}
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func incrementBytes(in []byte) []byte {
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rv := make([]byte, len(in))
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copy(rv, in)
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for i := len(rv) - 1; i >= 0; i-- {
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rv[i] = rv[i] + 1
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if rv[i] != 0 {
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return rv // didn't overflow, so stop
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}
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}
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return nil // overflowed
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}
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