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bucket.go
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bucket.go
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package vbolt
import (
"go.hasen.dev/generic"
"go.hasen.dev/vpack"
)
type BucketInfo[K, T any] struct {
Name string
KeyPackFn vpack.PackFn[K]
ValuePackFn vpack.PackFn[T]
}
func Bucket[K, T any](dbInfo *Info, name string, keyFn vpack.PackFn[K], serFn vpack.PackFn[T]) *BucketInfo[K, T] {
generic.Append(&dbInfo.BucketList, name)
generic.EnsureMapNotNil(&dbInfo.Infos)
result := &BucketInfo[K, T]{
Name: name,
KeyPackFn: keyFn,
ValuePackFn: serFn,
}
dbInfo.Infos[name] = result
return result
}
func HasKey[K, T any](tx *Tx, info *BucketInfo[K, T], id K) bool {
bkt := TxRawBucket(tx, info.Name)
return RawHasKey(bkt, vpack.ToBytes(&id, info.KeyPackFn))
}
func Read[K comparable, T any](tx *Tx, info *BucketInfo[K, T], id K, item *T) bool {
bkt := TxRawBucket(tx, info.Name)
return _Read(bkt, info, id, item)
}
func _Read[K comparable, T any](bkt *BBucket, info *BucketInfo[K, T], id K, item *T) bool {
if bkt == nil {
return false
}
var zero K
if id == zero {
return false
}
key := vpack.ToBytes(&id, info.KeyPackFn)
data := bkt.Get(key)
if data == nil {
return false
}
return vpack.FromBytesInto(data, item, info.ValuePackFn)
}
// ReadSlice reads objects given by ids, appending them to the given slice.
// returns the number of objects that were successfully read
func ReadSlice[K comparable, T any](tx *Tx, info *BucketInfo[K, T], ids []K, list *[]T) int {
bkt := TxRawBucket(tx, info.Name)
if bkt == nil {
return 0
}
count := 0
for _, id := range ids {
var item T
if _Read(bkt, info, id, &item) {
generic.Append(list, item)
count++
}
}
return count
}
// ReadSliceToMap reads objects given by id into the given map.
// returns the number of objects that were successfully read
func ReadSliceToMap[K comparable, T any](tx *Tx, info *BucketInfo[K, T], ids []K, itemsMap map[K]T) int {
bkt := TxRawBucket(tx, info.Name)
if bkt == nil {
return 0
}
count := 0
for _, id := range ids {
var item T
if _Read(bkt, info, id, &item) {
itemsMap[id] = item
count++
}
}
return count
}
// like read slice but for reading one item and appending it to a list
func ReadAppend[K comparable, T any](tx *Tx, info *BucketInfo[K, T], id K, list *[]T) bool {
var item T
if Read(tx, info, id, &item) {
generic.Append(list, item)
return true
} else {
return false
}
}
func ReadToMap[K comparable, T any](tx *Tx, info *BucketInfo[K, T], id K, itemsMap map[K]T) bool {
var item T
if Read(tx, info, id, &item) {
itemsMap[id] = item
return true
} else {
return false
}
}
// Writes an item to a key. Note: does not write anything if id is the zero value
func Write[K comparable, T any](tx *Tx, info *BucketInfo[K, T], id K, item *T) {
var zero K
if id == zero {
return
}
bkt := TxRawBucket(tx, info.Name)
key := vpack.ToBytes(&id, info.KeyPackFn)
data := vpack.ToBytes(item, info.ValuePackFn)
RawMustPut(bkt, key, data)
}
func Delete[K, T any](tx *Tx, info *BucketInfo[K, T], id K) {
bkt := TxRawBucket(tx, info.Name)
key := vpack.ToBytes(&id, info.KeyPackFn)
bkt.Delete(key)
}
func NextIntId[K, T any](tx *Tx, info *BucketInfo[K, T]) int {
bkt := TxRawBucket(tx, info.Name)
return int(RawNextSequence(bkt))
}
type _IterationDirection uint8
const _IterateRegular = _IterationDirection(0)
const _IterateReverse = _IterationDirection(1)
func _CursorStartPos(c *Cursor, direction _IterationDirection) (k []byte, v []byte) {
if direction == _IterateRegular {
return c.First()
}
if direction == _IterateReverse {
return c.Last()
}
return
}
func _CursorStep(c *Cursor, direction _IterationDirection) (k []byte, v []byte) {
if direction == _IterateRegular {
return c.Next()
}
if direction == _IterateReverse {
return c.Prev()
}
return
}
func _IterateCore[K, T any](bkt *BBucket, info *BucketInfo[K, T], direction _IterationDirection, visitFn func(key K, item T) bool) {
crsr := bkt.Cursor()
key, value := _CursorStartPos(crsr, direction)
for key != nil {
itemKey := vpack.FromBytes(key, info.KeyPackFn)
item := vpack.FromBytes(value, info.ValuePackFn)
if itemKey == nil || item == nil {
continue
}
if !visitFn(*itemKey, *item) {
break
}
key, value = _CursorStep(crsr, direction)
}
}
func IterateAll[K, T any](tx *Tx, info *BucketInfo[K, T], visitFn func(key K, item T) bool) {
bkt := TxRawBucket(tx, info.Name)
_IterateCore(bkt, info, _IterateRegular, visitFn)
}
func IterateAllReverse[K, T any](tx *Tx, info *BucketInfo[K, T], visitFn func(key K, item T) bool) {
bkt := TxRawBucket(tx, info.Name)
_IterateCore(bkt, info, _IterateReverse, visitFn)
}
func IterateInBatches[K, T any](tx *Tx, info *BucketInfo[K, T], batchSize int, visitFn func(items []T) bool) {
list := make([]T, 0, batchSize)
var key K
var done bool // iterator is done
for !done {
generic.ShrinkTo(&list, 0)
key, done = ScanList(tx, info, key, batchSize, &list)
if !visitFn(list) {
break
}
}
}
func ScanList[K, T any](tx *Tx, info *BucketInfo[K, T], startKey K, count int, items *[]T) (nextKey K, done bool) {
bkt := TxRawBucket(tx, info.Name)
crsr := bkt.Cursor()
key, value := crsr.Seek(vpack.ToBytes(&startKey, info.KeyPackFn))
for i := 0; i < count; i++ {
if key == nil { // end of bucket
break
}
var item T
if vpack.FromBytesInto(value, &item, info.ValuePackFn) {
generic.Append(items, item)
} else {
continue
}
key, value = crsr.Next()
}
done = key == nil
if !done {
vpack.FromBytesInto(key, &nextKey, info.KeyPackFn)
}
return
}