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set.go
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set.go
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package bitcaskdb
import (
"github.com/NNihilism/bitcaskdb/util"
art "github.com/NNihilism/bitcaskdb/ds/art"
"github.com/NNihilism/bitcaskdb/logfile"
)
// SAdd add the specified members to the set stored at key.
// Specified members that are already a member of this set are ignored.
// If key does not exist, a new set is created before adding the specified members.
func (db *BitcaskDB) SAdd(key []byte, members ...[]byte) (int, error) {
db.setIndex.mu.Lock()
defer db.setIndex.mu.Unlock()
if db.setIndex.trees[string(key)] == nil {
db.setIndex.trees[string(key)] = art.NewART()
}
idxTree := db.setIndex.trees[string(key)]
var cnt int
for _, mem := range members {
if len(mem) == 0 {
continue
}
if err := db.setIndex.murhash.Write(mem); err != nil {
return cnt, err
}
sum := db.setIndex.murhash.EncodeSum128()
db.setIndex.murhash.Reset()
// The elements in the set are unique
idxNode := idxTree.Get(sum)
if idxNode != nil {
continue
}
ent := &logfile.LogEntry{Key: key, Value: mem}
pos, err := db.writeLogEntry(ent, Set)
if err != nil {
return cnt, err
}
ent.Key = sum
if err := db.updateIndexTree(idxTree, ent, pos, true, Set); err != nil {
return cnt, err
}
cnt++
}
return cnt, nil
}
// SPop removes and returns one or more random members from the set value store at key.
func (db *BitcaskDB) SPop(key []byte, count uint) ([][]byte, error) {
db.setIndex.mu.Lock()
defer db.setIndex.mu.Unlock()
if db.setIndex.trees[string(key)] == nil {
return nil, nil
}
idxTree := db.setIndex.trees[string(key)]
var values [][]byte
iter := idxTree.Iterator()
for iter.HasNext() && count > 0 {
count--
node, _ := iter.Next()
if node == nil {
continue
}
val, err := db.getVal(idxTree, node.Key(), Set)
if err != nil {
return nil, err
}
values = append(values, val)
}
for _, val := range values {
if _, err := db.sremInternal(key, val); err != nil {
return nil, err
}
}
return values, nil
}
// SRem remove the specified members from the set stored at key.
// Specified members that are not a member of this set are ignored.
// If key does not exist, it is treated as an empty set and this command returns 0.
func (db *BitcaskDB) SRem(key []byte, members ...[]byte) (int, error) {
db.setIndex.mu.Lock()
defer db.setIndex.mu.Unlock()
if db.setIndex.trees[string(key)] == nil {
return 0, nil
}
var cnt int
for _, mem := range members {
if update, err := db.sremInternal(key, mem); err != nil {
return cnt, err
} else if update {
cnt++
}
}
return cnt, nil
}
// SIsMember returns if member is a member of the set stored at key.
func (db *BitcaskDB) SIsMember(key, member []byte) bool {
db.setIndex.mu.RLock()
defer db.setIndex.mu.RUnlock()
if db.setIndex.trees[string(key)] == nil {
return false
}
idxTree := db.setIndex.trees[string(key)]
if err := db.setIndex.murhash.Write(member); err != nil {
return false
}
sum := db.setIndex.murhash.EncodeSum128()
db.setIndex.murhash.Reset()
node := idxTree.Get(sum)
return node != nil
}
// SMembers returns all the members of the set value stored at key.
func (db *BitcaskDB) SMembers(key []byte) ([][]byte, error) {
db.setIndex.mu.RLock()
defer db.setIndex.mu.RUnlock()
return db.sMembers(key)
}
// SCard returns the set cardinality (number of elements) of the set stored at key.
func (db *BitcaskDB) SCard(key []byte) int {
db.setIndex.mu.RLock()
defer db.setIndex.mu.RUnlock()
if db.setIndex.trees[string(key)] == nil {
return 0
}
return db.setIndex.trees[string(key)].Size()
}
// SDiff returns the members of the set difference between the first set and
// all the successive sets. Returns error if no key is passed as a parameter.
func (db *BitcaskDB) SDiff(keys ...[]byte) ([][]byte, error) {
db.setIndex.mu.RLock()
defer db.setIndex.mu.RUnlock()
if len(keys) == 0 {
return nil, ErrWrongNumberOfArgs
}
firstSet, err := db.sMembers(keys[0])
if err != nil {
return nil, err
}
if len(keys) == 1 {
return firstSet, nil
}
successiveSet := make(map[uint64]struct{})
for _, key := range keys[1:] {
members, err := db.sMembers(key)
if err != nil {
return nil, err
}
for _, mem := range members {
h := util.MemHash(mem)
if _, ok := successiveSet[h]; !ok {
successiveSet[h] = struct{}{}
}
}
}
if len(successiveSet) == 0 {
return firstSet, nil
}
var values [][]byte
for _, mem := range firstSet {
h := util.MemHash(mem)
if _, ok := successiveSet[h]; !ok {
values = append(values, mem)
}
}
return values, nil
}
// SUnion returns the members of the set resulting from the union of all the given sets.
func (db *BitcaskDB) SUnion(keys ...[]byte) ([][]byte, error) {
db.setIndex.mu.RLock()
defer db.setIndex.mu.RUnlock()
if len(keys) == 0 {
return nil, ErrWrongNumberOfArgs
}
if len(keys) == 1 {
return db.sMembers(keys[0])
}
var values [][]byte
set := make(map[uint64]struct{})
for _, key := range keys {
members, err := db.sMembers(key)
if err != nil {
return nil, err
}
for _, mem := range members {
h := util.MemHash(mem)
if _, ok := set[h]; !ok {
set[h] = struct{}{}
values = append(values, mem)
}
}
}
return values, nil
}
func (db *BitcaskDB) sremInternal(key []byte, member []byte) (bool, error) {
idxTree := db.setIndex.trees[string(key)]
if err := db.setIndex.murhash.Write(member); err != nil {
return false, err
}
sum := db.setIndex.murhash.EncodeSum128()
db.setIndex.murhash.Reset()
oldVal, updated := idxTree.Delete(sum)
if !updated {
return false, nil
}
entry := &logfile.LogEntry{Key: key, Value: member, Type: logfile.TypeDelete}
pos, err := db.writeLogEntry(entry, Set)
if err != nil {
return false, err
}
db.sendDiscard(oldVal, updated, Set)
idxNode := &indexNode{fid: pos.fid, offset: pos.offset, entrySize: pos.entrySize}
db.sendDiscard(idxNode, true, Set)
return true, nil
}
// sMembers is a helper method to get all members of the given set key.
func (db *BitcaskDB) sMembers(key []byte) ([][]byte, error) {
idxTree := db.setIndex.trees[string(key)]
if idxTree == nil {
return nil, nil
}
var members [][]byte
iter := idxTree.Iterator()
for iter.HasNext() {
node, _ := iter.Next()
if node == nil {
continue
}
val, err := db.getVal(idxTree, node.Key(), Set)
if err != nil {
return nil, err
}
members = append(members, val)
}
return members, nil
}
// GetStrsKeys get all stored keys of type String.
func (db *BitcaskDB) GetSetKeys() ([][]byte, error) {
db.setIndex.mu.RLock()
defer db.setIndex.mu.RUnlock()
if db.setIndex.trees == nil {
return nil, nil
}
var keys [][]byte
for k := range db.setIndex.trees {
keys = append(keys, []byte(k))
}
return keys, nil
}