/usr/share/gocode/src/github.com/couchbase/moss/iterator_single.go is in golang-github-couchbase-moss-dev 0.0~git20170914.0.07c86e8-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 | // Copyright (c) 2016 Couchbase, Inc.
// 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 moss
import (
"bytes"
"io"
)
// An iteratorSingle implements the Iterator interface, and is an edge
// case optimization when there's only a single segment to iterate and
// there's no lower-level iterator. In contrast to the main iterator
// implementation, iteratorSingle doesn't have any heap operations.
type iteratorSingle struct {
s *segment
sc SegmentCursor
op uint64
k []byte
v []byte
closer io.Closer
options *CollectionOptions
iteratorOptions IteratorOptions
}
// Close must be invoked to release resources.
func (iter *iteratorSingle) Close() error {
if iter.closer != nil {
iter.closer.Close()
iter.closer = nil
}
return nil
}
func (iter *iteratorSingle) InitCloser(closer io.Closer) error {
if iter.closer != nil {
return ErrAlreadyInitialized
}
iter.closer = closer
return nil
}
// Next returns ErrIteratorDone if the iterator is done.
func (iter *iteratorSingle) Next() error {
err := iter.sc.Next()
if err != nil {
iter.op = 0
iter.k = nil
iter.v = nil
// we DO want to return ErrIteratorDone here
return err
}
iter.op, iter.k, iter.v = iter.sc.Current()
if iter.op != OperationDel ||
iter.iteratorOptions.IncludeDeletions {
return nil
}
return iter.Next()
}
func (iter *iteratorSingle) SeekTo(seekToKey []byte) error {
key, _, err := iter.Current()
if err != nil && err != ErrIteratorDone {
return err
}
if key != nil {
cmp := bytes.Compare(seekToKey, key)
if cmp == 0 {
return nil
}
if cmp > 0 {
// Try a loop of naive Next()'s for several attempts.
err = naiveSeekTo(iter, seekToKey, DefaultNaiveSeekToMaxTries)
if err != ErrMaxTries {
return err
}
}
}
iter.op = 0
iter.k = nil
iter.v = nil
err = iter.sc.Seek(seekToKey)
if err != nil {
// we DO want to return ErrIteratorDone here
return err
}
iter.op, iter.k, iter.v = iter.sc.Current()
if !iter.iteratorOptions.IncludeDeletions &&
iter.op == OperationDel {
return iter.Next()
}
return nil
}
// Current returns ErrIteratorDone if the iterator is done.
// Otherwise, Current() returns the current key and val, which should
// be treated as immutable or read-only. The key and val bytes will
// remain available until the next call to Next() or Close().
func (iter *iteratorSingle) Current() ([]byte, []byte, error) {
if iter.op == 0 {
return nil, nil, ErrIteratorDone
}
if iter.op == OperationDel {
return nil, nil, nil
}
if iter.op == OperationMerge {
var mo MergeOperator
if iter.options != nil {
mo = iter.options.MergeOperator
}
if mo == nil {
return iter.k, nil, ErrMergeOperatorNil
}
vMerged, ok := mo.FullMerge(iter.k, nil, [][]byte{iter.v})
if !ok {
return iter.k, nil, ErrMergeOperatorFullMergeFailed
}
return iter.k, vMerged, nil
}
return iter.k, iter.v, nil
}
// CurrentEx is a more advanced form of Current() that returns more
// metadata. It returns ErrIteratorDone if the iterator is done.
// Otherwise, the current operation, key, val are returned.
func (iter *iteratorSingle) CurrentEx() (
entryEx EntryEx, key, val []byte, err error) {
if iter.op == 0 {
return EntryEx{}, nil, nil, ErrIteratorDone
}
return EntryEx{Operation: iter.op}, iter.k, iter.v, nil
}
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