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entstore.go
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entstore.go
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package entity
import (
"bytes"
"github.com/adamcolton/luce/ds/lmap"
"github.com/adamcolton/luce/ds/slice"
"github.com/adamcolton/luce/lerr"
"github.com/adamcolton/luce/serial"
"github.com/adamcolton/luce/store"
"github.com/adamcolton/luce/util/filter"
"github.com/adamcolton/luce/util/liter"
)
const (
// ErrKeyNotFound is returned by Load when the key is not found the Store.
ErrKeyNotFound = lerr.Str("key not found")
// ErrIndexNotFound
ErrIndexNotFound = lerr.Str("index not found")
ErrIndexNameBlank = lerr.Str("index name was blank")
ErrIndexAlreadyDefined = lerr.Str("an index with the given name already exists")
)
// EntStore provides methods for saving and retreiving and Entity from a Store.
// The Serializer and Deserializer will be used for the Entity Value while
// EntKey will be used for the key.
type EntStore[T Entity] struct {
Init func() T
store.Store
serial.Serializer
serial.Deserializer
IdxStore store.Store
indexes lmap.Map[string, Indexer[T]]
}
// Load an entity. This requires that EntKey returns the key of the value to be
// loaded.
func (es *EntStore[T]) Load(ent T) error {
r := es.Store.Get(ent.EntKey())
if r.Value == nil {
return ErrKeyNotFound
}
return es.Deserialize(ent, r.Value)
}
func (es *EntStore[T]) AddIndex(name string, multi bool, fn func(T) []byte) StoreIndex[T] {
return es.AddIndexer(BaseIndexer[T]{
IndexName: name,
Fn: fn,
M: multi,
})
}
func (es *EntStore[T]) AddIndexer(idx Indexer[T]) StoreIndex[T] {
if es.indexes == nil {
es.indexes = make(lmap.Map[string, Indexer[T]])
}
name := idx.Name()
if name == "" {
lerr.Panic(ErrIndexNameBlank)
}
if _, found := es.indexes[name]; found {
lerr.Panic(ErrIndexAlreadyDefined)
}
es.indexes[name] = idx
return StoreIndex[T]{
idx: idx,
es: es,
}
}
// Get an entity by key.
func (es *EntStore[T]) Get(key []byte) (found bool, ent T, err error) {
r := es.Store.Get(key)
found = r.Value != nil
if !found {
return
}
ent = es.Init()
err = es.Deserialize(ent, r.Value)
if err != nil {
return
}
if set, ok := Entity(ent).(EntKeySetter); ok {
set.SetEntKey(key)
}
return
}
// GetSlice returns all entities in the Store if fn is nil and if fn is defined
// it returns all entities for which fn returns true given their key. If buf
// is provided, it will be used as the return slice.
func (es *EntStore[T]) GetSlice(fn filter.Filter[[]byte], buf []T) ([]T, error) {
i := store.NewIter(es.Store)
i.Filter = fn
return es.GetIter(i, buf)
}
func (es *EntStore[T]) GetIter(i liter.Iter[[]byte], buf []T) ([]T, error) {
var m lerr.Many
return slice.Transform(i, func(id []byte, _ int) (T, bool) {
found, e, err := es.Get(id)
m = m.Add(err)
return e, found
}), m.Cast()
}
// Put writes an entity to the store. If buf is provided, it will be used for
// Serialization.
func (es *EntStore[T]) Put(ent T, buf []byte) ([]byte, error) {
v, err := es.Serialize(ent, buf)
if err != nil {
return nil, err
}
ek := ent.EntKey()
err = es.Store.Put(ek, v)
if err != nil {
return nil, err
}
if es.IdxStore != nil {
es.updateIndexes(ek, ent)
}
return v, nil
}
func (es *EntStore[T]) updateIndexes(ek []byte, ent T) {
keysBkt := lerr.Must(es.IdxStore.Store([]byte("_keys")))
prevKeys := make(map[string][]byte)
if r := keysBkt.Get(ek); r.Found {
es.Deserializer.Deserialize(&prevKeys, r.Value)
}
keys := make(map[string][]byte, len(es.indexes))
for n, i := range es.indexes {
k := i.IndexKey(ent)
pk, ok := prevKeys[n]
if !ok || !bytes.Equal(k, pk) {
keys[n] = k
}
}
for n, k := range keys {
es.updateIdx(ek, k, prevKeys[n], es.indexes[n])
}
ks := lerr.Must(es.Serializer.Serialize(keys, nil))
keysBkt.Put(ek, ks)
}
func (es *EntStore[T]) Index(name string) (StoreIndex[T], bool) {
idx, found := es.indexes[name]
si := StoreIndex[T]{
es: es,
idx: idx,
}
return si, found
}
type StoreIndex[E Entity] struct {
idx Indexer[E]
es *EntStore[E]
}
func (si StoreIndex[E]) Lookup(idxKey []byte) (entIds liter.Iter[[]byte], err error) {
defer func() {
err, _ = recover().(error)
}()
entIds = si.es.idx(idxKey, si.idx)
return
}
func (si StoreIndex[E]) LookupEnts(idxKey []byte) (ents slice.Slice[E], err error) {
entIds, err := si.Lookup(idxKey)
if err == nil {
ents, err = si.es.GetIter(entIds, nil)
}
return
}
func (si StoreIndex[E]) Search(f filter.Filter[[]byte]) (idxKeys liter.Iter[[]byte], err error) {
i := store.NewIter(si.es.getIdxBkt(si.idx))
i.Filter = f
return i, nil
}
func (si StoreIndex[E]) SearchEnts(f filter.Filter[[]byte]) (ents slice.Slice[E], err error) {
s, _ := si.Search(f)
return si.MultiEntLookup(s)
}
func (si StoreIndex[E]) MultiLookup(idxKeys liter.Iter[[]byte]) (entIds liter.Iter[[]byte], err error) {
i := &liter.Nested[[]byte, []byte]{
Keys: idxKeys,
Lookup: func(key []byte) liter.Iter[[]byte] {
return lerr.Must(si.Lookup(key))
},
}
return i, nil
}
func (si StoreIndex[E]) MultiEntLookup(idxKeys liter.Iter[[]byte]) (ents slice.Slice[E], err error) {
entIds, err := si.MultiLookup(idxKeys)
if err == nil {
ents, err = si.es.GetIter(entIds, nil)
}
return
}