add name list
This commit is contained in:
Chris Lu
303
weed/util/skiplist/name_list.go
Normal file
303
weed/util/skiplist/name_list.go
Normal file
@@ -0,0 +1,303 @@
|
||||
package skiplist
|
||||
|
||||
import (
|
||||
"bytes"
|
||||
)
|
||||
|
||||
type NameList struct {
|
||||
skipList *SkipList
|
||||
batchSize int
|
||||
}
|
||||
|
||||
func NewNameList(store ListStore, batchSize int) *NameList {
|
||||
return &NameList{
|
||||
skipList: New(store),
|
||||
batchSize: batchSize,
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
Be reluctant to create new nodes. Try to fit into either previous node or next node.
|
||||
Prefer to add to previous node.
|
||||
|
||||
There are multiple cases after finding the name for greater or equal node
|
||||
1. found and node.Key == name
|
||||
The node contains a batch with leading key the same as the name
|
||||
nothing to do
|
||||
2. no such node found or node.Key > name
|
||||
|
||||
if no such node found
|
||||
prevNode = list.LargestNode
|
||||
|
||||
// case 2.1
|
||||
if previousNode contains name
|
||||
nothing to do
|
||||
|
||||
// prefer to add to previous node
|
||||
if prevNode != nil {
|
||||
// case 2.2
|
||||
if prevNode has capacity
|
||||
prevNode.add name, and save
|
||||
return
|
||||
// case 2.3
|
||||
split prevNode by name
|
||||
}
|
||||
|
||||
// case 2.4
|
||||
// merge into next node. Avoid too many nodes if adding data in reverse order.
|
||||
if nextNode is not nil and nextNode has capacity
|
||||
delete nextNode.Key
|
||||
nextNode.Key = name
|
||||
nextNode.batch.add name
|
||||
insert nodeNode.Key
|
||||
return
|
||||
|
||||
// case 2.5
|
||||
if prevNode is nil
|
||||
insert new node with key = name, value = batch{name}
|
||||
return
|
||||
|
||||
*/
|
||||
func (nl *NameList) WriteName(name string) error {
|
||||
lookupKey := []byte(name)
|
||||
prevNode, nextNode, found, err := nl.skipList.FindGreaterOrEqual(lookupKey)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
// case 1: the name already exists as one leading key in the batch
|
||||
if found && bytes.Compare(nextNode.Key, lookupKey) == 0 {
|
||||
return nil
|
||||
}
|
||||
|
||||
if !found {
|
||||
prevNode, err = nl.skipList.GetLargestNode()
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
|
||||
if nextNode != nil && prevNode == nil {
|
||||
prevNode, err = nl.skipList.loadElement(nextNode.Prev)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
|
||||
if prevNode != nil {
|
||||
prevNameBatch := LoadNameBatch(prevNode.Value)
|
||||
// case 2.1
|
||||
if prevNameBatch.ContainsName(name) {
|
||||
return nil
|
||||
}
|
||||
|
||||
// case 2.2
|
||||
if len(prevNameBatch.names) < nl.batchSize {
|
||||
prevNameBatch.WriteName(name)
|
||||
return nl.skipList.ChangeValue(prevNode, prevNameBatch.ToBytes())
|
||||
}
|
||||
|
||||
// case 2.3
|
||||
x, y := prevNameBatch.SplitBy(name)
|
||||
addToX := len(x.names) <= len(y.names)
|
||||
if len(x.names) != len(prevNameBatch.names) {
|
||||
if addToX {
|
||||
x.WriteName(name)
|
||||
}
|
||||
if x.key == prevNameBatch.key {
|
||||
if err := nl.skipList.ChangeValue(prevNode, x.ToBytes()); err != nil {
|
||||
return err
|
||||
}
|
||||
} else {
|
||||
if err := nl.skipList.Insert([]byte(x.key), x.ToBytes()); err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
}
|
||||
if len(y.names) != len(prevNameBatch.names) {
|
||||
if !addToX {
|
||||
y.WriteName(name)
|
||||
}
|
||||
if y.key == prevNameBatch.key {
|
||||
if err := nl.skipList.ChangeValue(prevNode, y.ToBytes()); err != nil {
|
||||
return err
|
||||
}
|
||||
} else {
|
||||
if err := nl.skipList.Insert([]byte(y.key), y.ToBytes()); err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
}
|
||||
return nil
|
||||
|
||||
}
|
||||
|
||||
// case 2.4
|
||||
if nextNode != nil {
|
||||
nextNameBatch := LoadNameBatch(nextNode.Value)
|
||||
if len(nextNameBatch.names) < nl.batchSize {
|
||||
if err := nl.skipList.Delete(nextNode.Key); err != nil {
|
||||
return err
|
||||
}
|
||||
nextNameBatch.WriteName(name)
|
||||
if err := nl.skipList.Insert([]byte(nextNameBatch.key), nextNameBatch.ToBytes()); err != nil {
|
||||
return err
|
||||
}
|
||||
return nil
|
||||
}
|
||||
}
|
||||
|
||||
// case 2.5
|
||||
// now prevNode is nil
|
||||
newNameBatch := NewNameBatch()
|
||||
newNameBatch.WriteName(name)
|
||||
if err := nl.skipList.Insert([]byte(newNameBatch.key), newNameBatch.ToBytes()); err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
/*
|
||||
// case 1: exists in nextNode
|
||||
if nextNode != nil && nextNode.Key == name {
|
||||
remove from nextNode, update nextNode
|
||||
// TODO: merge with prevNode if possible?
|
||||
return
|
||||
}
|
||||
if nextNode is nil
|
||||
prevNode = list.Largestnode
|
||||
if prevNode == nil and nextNode.Prev != nil
|
||||
prevNode = load(nextNode.Prev)
|
||||
|
||||
// case 2: does not exist
|
||||
// case 2.1
|
||||
if prevNode == nil {
|
||||
return
|
||||
}
|
||||
// case 2.2
|
||||
if prevNameBatch does not contain name {
|
||||
return
|
||||
}
|
||||
|
||||
// case 3
|
||||
delete from prevNameBatch
|
||||
if prevNameBatch + nextNode < capacityList
|
||||
// case 3.1
|
||||
merge
|
||||
else
|
||||
// case 3.2
|
||||
update prevNode
|
||||
|
||||
|
||||
*/
|
||||
func (nl *NameList) DeleteName(name string) error {
|
||||
lookupKey := []byte(name)
|
||||
prevNode, nextNode, found, err := nl.skipList.FindGreaterOrEqual(lookupKey)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
// case 1
|
||||
var nextNameBatch *NameBatch
|
||||
if nextNode != nil {
|
||||
nextNameBatch = LoadNameBatch(nextNode.Value)
|
||||
}
|
||||
if found && bytes.Compare(nextNode.Key, lookupKey) == 0 {
|
||||
if err := nl.skipList.Delete(nextNode.Key); err != nil {
|
||||
return err
|
||||
}
|
||||
nextNameBatch.DeleteName(name)
|
||||
if len(nextNameBatch.names) > 0 {
|
||||
if err := nl.skipList.Insert([]byte(nextNameBatch.key), nextNameBatch.ToBytes()); err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
if !found {
|
||||
prevNode, err = nl.skipList.GetLargestNode()
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
|
||||
if nextNode != nil && prevNode == nil {
|
||||
prevNode, err = nl.skipList.loadElement(nextNode.Prev)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
|
||||
// case 2
|
||||
if prevNode == nil {
|
||||
// case 2.1
|
||||
return nil
|
||||
}
|
||||
prevNameBatch := LoadNameBatch(prevNode.Value)
|
||||
if !prevNameBatch.ContainsName(name) {
|
||||
// case 2.2
|
||||
return nil
|
||||
}
|
||||
|
||||
// case 3
|
||||
prevNameBatch.DeleteName(name)
|
||||
if len(prevNameBatch.names) == 0 {
|
||||
if err := nl.skipList.Delete(prevNode.Key); err != nil {
|
||||
return err
|
||||
}
|
||||
return nil
|
||||
}
|
||||
if nextNameBatch != nil && len(nextNameBatch.names) + len(prevNameBatch.names) < nl.batchSize {
|
||||
// case 3.1 merge nextNode and prevNode
|
||||
if err := nl.skipList.Delete(nextNode.Key); err != nil {
|
||||
return err
|
||||
}
|
||||
for nextName := range nextNameBatch.names {
|
||||
prevNameBatch.WriteName(nextName)
|
||||
}
|
||||
return nl.skipList.ChangeValue(prevNode, prevNameBatch.ToBytes())
|
||||
} else {
|
||||
// case 3.2 update prevNode
|
||||
return nl.skipList.ChangeValue(prevNode, prevNameBatch.ToBytes())
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
func (nl *NameList) ListNames(startFrom string, visitNamesFn func(name string) bool) error {
|
||||
lookupKey := []byte(startFrom)
|
||||
prevNode, nextNode, found, err := nl.skipList.FindGreaterOrEqual(lookupKey)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
if found && bytes.Compare(nextNode.Key, lookupKey) == 0 {
|
||||
prevNode = nil
|
||||
}
|
||||
if !found {
|
||||
prevNode, err = nl.skipList.GetLargestNode()
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
|
||||
if prevNode != nil {
|
||||
prevNameBatch := LoadNameBatch(prevNode.Value)
|
||||
if !prevNameBatch.ListNames(startFrom, visitNamesFn) {
|
||||
return nil
|
||||
}
|
||||
}
|
||||
|
||||
for nextNode != nil {
|
||||
nextNameBatch := LoadNameBatch(nextNode.Value)
|
||||
if !nextNameBatch.ListNames(startFrom, visitNamesFn) {
|
||||
return nil
|
||||
}
|
||||
nextNode, err = nl.skipList.loadElement(nextNode.Next[0])
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
Reference in New Issue
Block a user