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package memory
import (
"bytes"
"sort"
"github.com/iden3/go-merkletree/db"
)
// Storage implements the db.Storage interface
type Storage struct {
prefix []byte
kv db.KvMap
}
// StorageTx implements the db.Tx interface
type StorageTx struct {
s *Storage
kv db.KvMap
}
// NewMemoryStorage returns a new Storage
func NewMemoryStorage() *Storage {
kvmap := make(db.KvMap)
return &Storage{[]byte{}, kvmap}
}
// WithPrefix implements the method WithPrefix of the interface db.Storage
func (m *Storage) WithPrefix(prefix []byte) db.Storage {
return &Storage{db.Concat(m.prefix, prefix), m.kv}
}
// NewTx implements the method NewTx of the interface db.Storage
func (m *Storage) NewTx() (db.Tx, error) {
return &StorageTx{m, make(db.KvMap)}, nil
}
// Get retreives a value from a key in the db.Storage
func (m *Storage) Get(key []byte) ([]byte, error) {
if v, ok := m.kv.Get(db.Concat(m.prefix, key[:])); ok {
return v, nil
}
return nil, db.ErrNotFound
}
// Iterate implements the method Iterate of the interface db.Storage
func (m *Storage) Iterate(f func([]byte, []byte) (bool, error)) error {
kvs := make([]db.KV, 0)
for _, v := range m.kv {
if len(v.K) < len(m.prefix) ||
!bytes.Equal(v.K[:len(m.prefix)], m.prefix) {
continue
}
localkey := v.K[len(m.prefix):]
kvs = append(kvs, db.KV{K: localkey, V: v.V})
}
sort.SliceStable(kvs, func(i, j int) bool {
return bytes.Compare(kvs[i].K, kvs[j].K) < 0
})
for _, kv := range kvs {
if cont, err := f(kv.K, kv.V); err != nil {
return err
} else if !cont {
break
}
}
return nil
}
// Get implements the method Get of the interface db.Tx
func (tx *StorageTx) Get(key []byte) ([]byte, error) {
if v, ok := tx.kv.Get(db.Concat(tx.s.prefix, key)); ok {
return v, nil
}
if v, ok := tx.s.kv.Get(db.Concat(tx.s.prefix, key)); ok {
return v, nil
}
return nil, db.ErrNotFound
}
// Put implements the method Put of the interface db.Tx
func (tx *StorageTx) Put(k, v []byte) error {
tx.kv.Put(db.Concat(tx.s.prefix, k), v)
return nil
}
// Commit implements the method Commit of the interface db.Tx
func (tx *StorageTx) Commit() error {
for _, v := range tx.kv {
tx.s.kv.Put(v.K, v.V)
}
tx.kv = nil
return nil
}
// Add implements the method Add of the interface db.Tx
func (tx *StorageTx) Add(atx db.Tx) error {
mstx := atx.(*StorageTx)
for _, v := range mstx.kv {
tx.kv.Put(v.K, v.V)
}
return nil
}
// Close implements the method Close of the interface db.Tx
func (tx *StorageTx) Close() {
tx.kv = nil
}
// Close implements the method Close of the interface db.Storage
func (m *Storage) Close() {
}
// List implements the method List of the interface db.Storage
func (m *Storage) List(limit int) ([]db.KV, error) {
ret := []db.KV{}
err := m.Iterate(func(key []byte, value []byte) (bool, error) {
ret = append(ret, db.KV{K: db.Clone(key), V: db.Clone(value)})
if len(ret) == limit {
return false, nil
}
return true, nil
})
return ret, err
}