114 lines
2.1 KiB
Go
114 lines
2.1 KiB
Go
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// 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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