a9c07acbfa
refactor to share code in emulated batch refactor to share code in emulated merge refactor index kvstore benchmarks to share more code refactor index kvstore benchmarks to be more repeatable
114 lines
2.1 KiB
Go
114 lines
2.1 KiB
Go
// Copyright (c) 2015 Couchbase, Inc.
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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
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// License. You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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// Unless required by applicable law or agreed to in writing,
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// software distributed under the License is distributed on an "AS
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// IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
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// express or implied. See the License for the specific language
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// governing permissions and limitations under the License.
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// +build go1.4
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package cznicb
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import (
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"errors"
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"github.com/cznic/b"
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)
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var iteratorDoneErr = errors.New("iteratorDoneErr") // A sentinel value.
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type Iterator struct { // Assuming that iterators are used single-threaded.
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s *Store
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e *b.Enumerator
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currK interface{}
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currV interface{}
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currErr error
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}
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func (i *Iterator) SeekFirst() {
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i.currK = nil
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i.currV = nil
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i.currErr = nil
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var err error
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i.s.m.RLock()
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i.e, err = i.s.t.SeekFirst()
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i.s.m.RUnlock() // cannot defer, must unlock before Next
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if err != nil {
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i.currK = nil
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i.currV = nil
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i.currErr = iteratorDoneErr
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}
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i.Next()
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}
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func (i *Iterator) Seek(k []byte) {
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i.currK = nil
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i.currV = nil
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i.currErr = nil
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i.s.m.RLock()
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i.e, _ = i.s.t.Seek(k)
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i.s.m.RUnlock() // cannot defer, must unlock before Next
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i.Next()
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}
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func (i *Iterator) Next() {
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if i.currErr != nil {
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i.currK = nil
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i.currV = nil
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i.currErr = iteratorDoneErr
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return
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}
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i.s.m.RLock()
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defer i.s.m.RUnlock()
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i.currK, i.currV, i.currErr = i.e.Next()
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}
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func (i *Iterator) Current() ([]byte, []byte, bool) {
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if i.currErr == iteratorDoneErr ||
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i.currK == nil ||
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i.currV == nil {
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return nil, nil, false
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}
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return i.currK.([]byte), i.currV.([]byte), true
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}
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func (i *Iterator) Key() []byte {
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k, _, ok := i.Current()
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if !ok {
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return nil
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}
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return k
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}
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func (i *Iterator) Value() []byte {
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_, v, ok := i.Current()
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if !ok {
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return nil
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}
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return v
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}
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func (i *Iterator) Valid() bool {
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_, _, ok := i.Current()
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return ok
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}
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func (i *Iterator) Close() error {
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if i.e != nil {
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i.e.Close()
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}
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i.e = nil
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return nil
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}
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