1package memory
  2
  3import (
  4	"bytes"
  5	"sort"
  6
  7	"github.com/iden3/go-merkletree/db"
  8)
  9
 10// Storage implements the db.Storage interface
 11type Storage struct {
 12	prefix []byte
 13	kv     db.KvMap
 14}
 15
 16// StorageTx implements the db.Tx interface
 17type StorageTx struct {
 18	s  *Storage
 19	kv db.KvMap
 20}
 21
 22// NewMemoryStorage returns a new Storage
 23func NewMemoryStorage() *Storage {
 24	kvmap := make(db.KvMap)
 25	return &Storage{[]byte{}, kvmap}
 26}
 27
 28// Info implements the method Info of the interface db.Storage
 29func (m *Storage) Info() string {
 30	return "in-memory"
 31}
 32
 33// WithPrefix implements the method WithPrefix of the interface db.Storage
 34func (m *Storage) WithPrefix(prefix []byte) db.Storage {
 35	return &Storage{db.Concat(m.prefix, prefix), m.kv}
 36}
 37
 38// NewTx implements the method NewTx of the interface db.Storage
 39func (m *Storage) NewTx() (db.Tx, error) {
 40	return &StorageTx{m, make(db.KvMap)}, nil
 41}
 42
 43// Get retreives a value from a key in the db.Storage
 44func (m *Storage) Get(key []byte) ([]byte, error) {
 45	if v, ok := m.kv.Get(db.Concat(m.prefix, key[:])); ok {
 46		return v, nil
 47	}
 48	return nil, db.ErrNotFound
 49}
 50
 51// Iterate implements the method Iterate of the interface db.Storage
 52func (m *Storage) Iterate(f func([]byte, []byte) (bool, error)) error {
 53	kvs := make([]db.KV, 0)
 54	for _, v := range m.kv {
 55		if len(v.K) < len(m.prefix) ||
 56			!bytes.Equal(v.K[:len(m.prefix)], m.prefix) {
 57			continue
 58		}
 59		localkey := v.K[len(m.prefix):]
 60		kvs = append(kvs, db.KV{K: localkey, V: v.V})
 61	}
 62	sort.SliceStable(kvs, func(i, j int) bool {
 63		return bytes.Compare(kvs[i].K, kvs[j].K) < 0
 64	})
 65
 66	for _, kv := range kvs {
 67		if cont, err := f(kv.K, kv.V); err != nil {
 68			return err
 69		} else if !cont {
 70			break
 71		}
 72	}
 73	return nil
 74}
 75
 76// Get implements the method Get of the interface db.Tx
 77func (tx *StorageTx) Get(key []byte) ([]byte, error) {
 78	if v, ok := tx.kv.Get(db.Concat(tx.s.prefix, key)); ok {
 79		return v, nil
 80	}
 81	if v, ok := tx.s.kv.Get(db.Concat(tx.s.prefix, key)); ok {
 82		return v, nil
 83	}
 84
 85	return nil, db.ErrNotFound
 86}
 87
 88// Put implements the method Put of the interface db.Tx
 89func (tx *StorageTx) Put(k, v []byte) error {
 90	tx.kv.Put(db.Concat(tx.s.prefix, k), v)
 91	return nil
 92}
 93
 94// Commit implements the method Commit of the interface db.Tx
 95func (tx *StorageTx) Commit() error {
 96	for _, v := range tx.kv {
 97		tx.s.kv.Put(v.K, v.V)
 98	}
 99	tx.kv = nil
100	return nil
101}
102
103// Add implements the method Add of the interface db.Tx
104func (tx *StorageTx) Add(atx db.Tx) error {
105	mstx := atx.(*StorageTx)
106	for _, v := range mstx.kv {
107		tx.kv.Put(v.K, v.V)
108	}
109	return nil
110}
111
112// Close implements the method Close of the interface db.Tx
113func (tx *StorageTx) Close() {
114	tx.kv = nil
115}
116
117// Close implements the method Close of the interface db.Storage
118func (m *Storage) Close() {
119}
120
121// List implements the method List of the interface db.Storage
122func (m *Storage) List(limit int) ([]db.KV, error) {
123	ret := []db.KV{}
124	err := m.Iterate(func(key []byte, value []byte) (bool, error) {
125		ret = append(ret, db.KV{K: db.Clone(key), V: db.Clone(value)})
126		if len(ret) == limit {
127			return false, nil
128		}
129		return true, nil
130	})
131	return ret, err
132}