/
dictionary.go
121 lines (104 loc) · 2.69 KB
/
dictionary.go
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// Copyright (c) 2020 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 index
import (
"container/heap"
segment "github.com/blugelabs/bluge_segment_api"
)
type segmentDictCursor struct {
dict segment.Dictionary
itr segment.DictionaryIterator
curr segment.DictionaryEntry
}
type dictionaryEntry struct {
term string
count uint64
}
func (d *dictionaryEntry) Term() string {
return d.term
}
func (d *dictionaryEntry) Count() uint64 {
return d.count
}
type dictionary struct {
snapshot *Snapshot
cursors []*segmentDictCursor
entry dictionaryEntry
}
func (i *dictionary) Len() int { return len(i.cursors) }
func (i *dictionary) Less(a, b int) bool {
return i.cursors[a].curr.Term() < i.cursors[b].curr.Term()
}
func (i *dictionary) Swap(a, b int) {
i.cursors[a], i.cursors[b] = i.cursors[b], i.cursors[a]
}
func (i *dictionary) Push(x interface{}) {
i.cursors = append(i.cursors, x.(*segmentDictCursor))
}
func (i *dictionary) Pop() interface{} {
n := len(i.cursors)
x := i.cursors[n-1]
i.cursors = i.cursors[0 : n-1]
return x
}
func (i *dictionary) Next() (segment.DictionaryEntry, error) {
if len(i.cursors) == 0 {
return nil, nil
}
i.entry.term = i.cursors[0].curr.Term()
i.entry.count = i.cursors[0].curr.Count()
next, err := i.cursors[0].itr.Next()
if err != nil {
return nil, err
}
if next == nil {
// at end of this cursor, remove it
heap.Pop(i)
} else {
// modified heap, fix it
i.cursors[0].curr = next
heap.Fix(i, 0)
}
// look for any other entries with the exact same term
for len(i.cursors) > 0 && i.cursors[0].curr.Term() == i.entry.Term() {
i.entry.count += i.cursors[0].curr.Count()
next, err := i.cursors[0].itr.Next()
if err != nil {
return nil, err
}
if next == nil {
// at end of this cursor, remove it
heap.Pop(i)
} else {
// modified heap, fix it
i.cursors[0].curr = next
heap.Fix(i, 0)
}
}
return &i.entry, nil
}
func (i *dictionary) Close() error {
return nil
}
func (i *dictionary) Contains(key []byte) (bool, error) {
if len(i.cursors) == 0 {
return false, nil
}
for _, cursor := range i.cursors {
if found, _ := cursor.dict.Contains(key); found {
return true, nil
}
}
return false, nil
}