306 lines
5.3 KiB
Go
306 lines
5.3 KiB
Go
// Copyright (c) 2015 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 gtreap provides an in-memory implementation of the
|
|
// KVStore interfaces using the gtreap balanced-binary treap,
|
|
// copy-on-write data structure.
|
|
package gtreap
|
|
|
|
import (
|
|
"bytes"
|
|
"math/rand"
|
|
"sync"
|
|
|
|
"github.com/blevesearch/bleve/index/store"
|
|
"github.com/blevesearch/bleve/registry"
|
|
|
|
"github.com/steveyen/gtreap"
|
|
)
|
|
|
|
const Name = "gtreap"
|
|
|
|
func init() {
|
|
registry.RegisterKVStore(Name, StoreConstructor)
|
|
}
|
|
|
|
func StoreConstructor(config map[string]interface{}) (store.KVStore, error) {
|
|
return &Store{t: gtreap.NewTreap(itemCompare)}, nil
|
|
}
|
|
|
|
type Item struct {
|
|
k []byte
|
|
v []byte
|
|
}
|
|
|
|
func itemCompare(a, b interface{}) int {
|
|
return bytes.Compare(a.(*Item).k, b.(*Item).k)
|
|
}
|
|
|
|
type Store struct {
|
|
m sync.Mutex
|
|
t *gtreap.Treap
|
|
}
|
|
|
|
type Reader struct {
|
|
t *gtreap.Treap
|
|
}
|
|
|
|
type Iterator struct {
|
|
t *gtreap.Treap
|
|
|
|
m sync.Mutex
|
|
cancelCh chan struct{}
|
|
nextCh chan *Item
|
|
curr *Item
|
|
currOk bool
|
|
}
|
|
|
|
func newIterator(t *gtreap.Treap) *Iterator {
|
|
return &Iterator{t: t}
|
|
}
|
|
|
|
type Batch struct {
|
|
s *Store
|
|
items []*Item
|
|
ms map[string]store.AssociativeMergeChain
|
|
}
|
|
|
|
func (s *Store) Close() error {
|
|
return nil
|
|
}
|
|
|
|
func (s *Store) Reader() (store.KVReader, error) {
|
|
s.m.Lock()
|
|
t := s.t
|
|
s.m.Unlock()
|
|
return &Reader{t: t}, nil
|
|
}
|
|
|
|
func (s *Store) Writer() (store.KVWriter, error) {
|
|
return s, nil
|
|
}
|
|
|
|
func (w *Reader) Get(k []byte) (v []byte, err error) {
|
|
itm := w.t.Get(&Item{k: k})
|
|
if itm != nil {
|
|
return itm.(*Item).v, nil
|
|
}
|
|
return nil, nil
|
|
}
|
|
|
|
func (w *Reader) Iterator(k []byte) store.KVIterator {
|
|
return newIterator(w.t).restart(&Item{k: k})
|
|
}
|
|
|
|
func (w *Reader) Close() error {
|
|
return nil
|
|
}
|
|
|
|
func (w *Store) Get(k []byte) (v []byte, err error) {
|
|
w.m.Lock()
|
|
t := w.t
|
|
w.m.Unlock()
|
|
|
|
itm := t.Get(&Item{k: k})
|
|
if itm != nil {
|
|
return itm.(*Item).v, nil
|
|
}
|
|
return nil, nil
|
|
}
|
|
|
|
func (w *Store) Iterator(k []byte) store.KVIterator {
|
|
w.m.Lock()
|
|
t := w.t
|
|
w.m.Unlock()
|
|
return newIterator(t).restart(&Item{k: k})
|
|
}
|
|
|
|
func (w *Store) Set(k, v []byte) (err error) {
|
|
w.m.Lock()
|
|
w.t = w.t.Upsert(&Item{k: k, v: v}, rand.Int())
|
|
w.m.Unlock()
|
|
return nil
|
|
}
|
|
|
|
func (w *Store) Delete(k []byte) (err error) {
|
|
w.m.Lock()
|
|
w.t = w.t.Delete(&Item{k: k})
|
|
w.m.Unlock()
|
|
return nil
|
|
}
|
|
|
|
func (w *Store) NewBatch() store.KVBatch {
|
|
return &Batch{
|
|
s: w,
|
|
items: make([]*Item, 0, 100),
|
|
ms: map[string]store.AssociativeMergeChain{},
|
|
}
|
|
}
|
|
|
|
func (w *Iterator) SeekFirst() {
|
|
min := w.t.Min()
|
|
if min != nil {
|
|
w.restart(min.(*Item))
|
|
} else {
|
|
w.restart(nil)
|
|
}
|
|
}
|
|
|
|
func (w *Iterator) Seek(k []byte) {
|
|
w.restart(&Item{k: k})
|
|
}
|
|
|
|
func (w *Iterator) restart(start *Item) *Iterator {
|
|
cancelCh := make(chan struct{})
|
|
nextCh := make(chan *Item, 1)
|
|
|
|
w.m.Lock()
|
|
if w.cancelCh != nil {
|
|
close(w.cancelCh)
|
|
}
|
|
w.cancelCh = cancelCh
|
|
w.nextCh = nextCh
|
|
w.curr = nil
|
|
w.currOk = false
|
|
w.m.Unlock()
|
|
|
|
go func() {
|
|
if start != nil {
|
|
w.t.VisitAscend(start, func(itm gtreap.Item) bool {
|
|
select {
|
|
case <-cancelCh:
|
|
return false
|
|
case nextCh <- itm.(*Item):
|
|
return true
|
|
}
|
|
})
|
|
}
|
|
close(nextCh)
|
|
}()
|
|
|
|
w.Next()
|
|
|
|
return w
|
|
}
|
|
|
|
func (w *Iterator) Next() {
|
|
w.m.Lock()
|
|
nextCh := w.nextCh
|
|
w.m.Unlock()
|
|
w.curr, w.currOk = <-nextCh
|
|
}
|
|
|
|
func (w *Iterator) Current() ([]byte, []byte, bool) {
|
|
w.m.Lock()
|
|
defer w.m.Unlock()
|
|
if !w.currOk || w.curr == nil {
|
|
return nil, nil, false
|
|
}
|
|
return w.curr.k, w.curr.v, w.currOk
|
|
}
|
|
|
|
func (w *Iterator) Key() []byte {
|
|
k, _, ok := w.Current()
|
|
if !ok {
|
|
return nil
|
|
}
|
|
return k
|
|
}
|
|
|
|
func (w *Iterator) Value() []byte {
|
|
_, v, ok := w.Current()
|
|
if !ok {
|
|
return nil
|
|
}
|
|
return v
|
|
}
|
|
|
|
func (w *Iterator) Valid() bool {
|
|
_, _, ok := w.Current()
|
|
return ok
|
|
}
|
|
|
|
func (w *Iterator) Close() error {
|
|
w.m.Lock()
|
|
if w.cancelCh != nil {
|
|
close(w.cancelCh)
|
|
}
|
|
w.cancelCh = nil
|
|
w.nextCh = nil
|
|
w.curr = nil
|
|
w.currOk = false
|
|
w.m.Unlock()
|
|
|
|
return nil
|
|
}
|
|
|
|
func (w *Batch) Set(k, v []byte) {
|
|
w.items = append(w.items, &Item{k, v})
|
|
}
|
|
|
|
func (w *Batch) Delete(k []byte) {
|
|
w.items = append(w.items, &Item{k, nil})
|
|
}
|
|
|
|
func (w *Batch) Merge(k []byte, oper store.AssociativeMerge) {
|
|
w.ms[string(k)] = append(w.ms[string(k)], oper)
|
|
}
|
|
|
|
func (w *Batch) Execute() (err error) {
|
|
done := false
|
|
for !done {
|
|
w.s.m.Lock()
|
|
torig := w.s.t
|
|
w.s.m.Unlock()
|
|
|
|
t := torig
|
|
for key, mc := range w.ms {
|
|
k := []byte(key)
|
|
itm := t.Get(&Item{k: k})
|
|
v := []byte(nil)
|
|
if itm != nil {
|
|
v = itm.(*Item).v
|
|
}
|
|
v, err := mc.Merge(k, v)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if v != nil {
|
|
t = t.Upsert(&Item{k: k, v: v}, rand.Int())
|
|
} else {
|
|
t = t.Delete(&Item{k: k})
|
|
}
|
|
}
|
|
|
|
for _, item := range w.items {
|
|
v := item.v
|
|
if v != nil {
|
|
t = t.Upsert(item, rand.Int())
|
|
} else {
|
|
t = t.Delete(item)
|
|
}
|
|
}
|
|
|
|
w.s.m.Lock()
|
|
if w.s.t == torig {
|
|
w.s.t = t
|
|
done = true
|
|
}
|
|
w.s.m.Unlock()
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func (w *Batch) Close() error {
|
|
return nil
|
|
}
|