neo-go/pkg/core/storage/store.go
Anna Shaleva 09186127da core: adjust the documentation of SeekRange's Prefix field
It is used in different context (seeking through the storage or
through the contract storage), and sometimes empty prefix is not
supported.
2023-02-18 21:06:30 +03:00

175 lines
6 KiB
Go

package storage
import (
"errors"
"fmt"
"github.com/nspcc-dev/neo-go/pkg/core/storage/dbconfig"
"github.com/nspcc-dev/neo-go/pkg/core/storage/dboper"
"github.com/syndtr/goleveldb/leveldb/util"
)
// KeyPrefix constants.
const (
DataExecutable KeyPrefix = 0x01
// DataMPT is used for MPT node entries identified by Uint256.
DataMPT KeyPrefix = 0x03
// DataMPTAux is used to store additional MPT data like height-root
// mappings and local/validated heights.
DataMPTAux KeyPrefix = 0x04
STStorage KeyPrefix = 0x70
// STTempStorage is used to store contract storage items during state sync process
// in order not to mess up the previous state which has its own items stored by
// STStorage prefix. Once state exchange process is completed, all items with
// STStorage prefix will be replaced with STTempStorage-prefixed ones.
STTempStorage KeyPrefix = 0x71
STNEP11Transfers KeyPrefix = 0x72
STNEP17Transfers KeyPrefix = 0x73
STTokenTransferInfo KeyPrefix = 0x74
IXHeaderHashList KeyPrefix = 0x80
SYSCurrentBlock KeyPrefix = 0xc0
SYSCurrentHeader KeyPrefix = 0xc1
SYSStateSyncCurrentBlockHeight KeyPrefix = 0xc2
SYSStateSyncPoint KeyPrefix = 0xc3
// SYSStateChangeStage is used to store the phase of a state changing process
// which is one of the state jump or state reset. Its value is one byte containing
// state reset / state jump stages bits (first seven bits are reserved for that)
// and the last bit reserved for the state reset process marker (set to 1 on
// unfinished state reset and to 0 on unfinished state jump).
SYSStateChangeStage KeyPrefix = 0xc4
SYSVersion KeyPrefix = 0xf0
)
// Executable subtypes.
const (
ExecBlock byte = 1
ExecTransaction byte = 2
)
// SeekRange represents options for Store.Seek operation.
type SeekRange struct {
// Prefix denotes the Seek's lookup key.
// If used directly with MemCachedStore's or MemoryStore's Seek, SeekAsync or
// SeekGC empty Prefix is not supported due to internal MemoryStore cache
// architecture; otherwise empty prefix can be used safely.
Prefix []byte
// Start denotes value appended to the Prefix to start Seek from.
// Seeking starting from some key includes this key to the result;
// if no matching key was found then next suitable key is picked up.
// Start may be empty. Empty Start means seeking through all keys in
// the DB with matching Prefix.
// Empty Prefix and empty Start can be combined, which means seeking
// through all keys in the DB, but see the Prefix's comment.
Start []byte
// Backwards denotes whether Seek direction should be reversed, i.e.
// whether seeking should be performed in a descending way.
// Backwards can be safely combined with Prefix and Start.
Backwards bool
// SearchDepth is the depth of Seek operation, denotes the number of cached
// DAO layers to perform search. Use 1 to fetch the latest changes from upper
// in-memory layer of cached DAO. Default 0 value denotes searching through
// the whole set of cached layers.
SearchDepth int
}
// ErrKeyNotFound is an error returned by Store implementations
// when a certain key is not found.
var ErrKeyNotFound = errors.New("key not found")
type (
// Store is the underlying KV backend for the blockchain data, it's
// not intended to be used directly, you wrap it with some memory cache
// layer most of the time.
Store interface {
Get([]byte) ([]byte, error)
// PutChangeSet allows to push prepared changeset to the Store.
PutChangeSet(puts map[string][]byte, stor map[string][]byte) error
// Seek can guarantee that provided key (k) and value (v) are the only valid until the next call to f.
// Seek continues iteration until false is returned from f.
// Key and value slices should not be modified.
// Seek can guarantee that key-value items are sorted by key in ascending way.
Seek(rng SeekRange, f func(k, v []byte) bool)
// SeekGC is similar to Seek, but the function should return true if current
// KV pair should be kept and false if it's to be deleted; there is no way to
// do an early exit here. SeekGC only works with the current Store, it won't
// go down to layers below and it takes a full write lock, so use it carefully.
SeekGC(rng SeekRange, keep func(k, v []byte) bool) error
Close() error
}
// KeyPrefix is a constant byte added as a prefix for each key
// stored.
KeyPrefix uint8
)
func seekRangeToPrefixes(sr SeekRange) *util.Range {
var (
rang *util.Range
start = make([]byte, len(sr.Prefix)+len(sr.Start))
)
copy(start, sr.Prefix)
copy(start[len(sr.Prefix):], sr.Start)
if !sr.Backwards {
rang = util.BytesPrefix(sr.Prefix)
rang.Start = start
} else {
rang = util.BytesPrefix(start)
rang.Start = sr.Prefix
}
return rang
}
// NewStore creates storage with preselected in configuration database type.
func NewStore(cfg dbconfig.DBConfiguration) (Store, error) {
var store Store
var err error
switch cfg.Type {
case dbconfig.LevelDB:
store, err = NewLevelDBStore(cfg.LevelDBOptions)
case dbconfig.InMemoryDB:
store = NewMemoryStore()
case dbconfig.BoltDB:
store, err = NewBoltDBStore(cfg.BoltDBOptions)
default:
return nil, fmt.Errorf("unknown storage: %s", cfg.Type)
}
return store, err
}
// BatchToOperations converts a batch of changes into array of dboper.Operation.
func BatchToOperations(batch *MemBatch) []dboper.Operation {
size := len(batch.Put) + len(batch.Deleted)
ops := make([]dboper.Operation, 0, size)
for i := range batch.Put {
key := batch.Put[i].Key
if len(key) == 0 || key[0] != byte(STStorage) && key[0] != byte(STTempStorage) {
continue
}
op := "Added"
if batch.Put[i].Exists {
op = "Changed"
}
ops = append(ops, dboper.Operation{
State: op,
Key: key[1:],
Value: batch.Put[i].Value,
})
}
for i := range batch.Deleted {
key := batch.Deleted[i].Key
if len(key) == 0 || !batch.Deleted[i].Exists ||
key[0] != byte(STStorage) && key[0] != byte(STTempStorage) {
continue
}
ops = append(ops, dboper.Operation{
State: "Deleted",
Key: key[1:],
})
}
return ops
}