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node.go
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node.go
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//go:generate protoc -I=. -I=$GOPATH/src -I=$GOPATH/src/github.com/ElrondNetwork/protobuf/protobuf --gogoslick_out=. node.proto
package trie
import (
"context"
"encoding/hex"
"fmt"
"time"
"github.com/ElrondNetwork/elrond-go-core/hashing"
"github.com/ElrondNetwork/elrond-go-core/marshal"
"github.com/ElrondNetwork/elrond-go/common"
)
const (
nrOfChildren = 17
firstByte = 0
hexTerminator = 16
nibbleSize = 4
nibbleMask = 0x0f
pointerSizeInBytes = 8
numNodeInnerPointers = 2 // each trie node contains a marshalizer and a hasher
pollingIdleNode = time.Millisecond
)
type baseNode struct {
hash []byte
dirty bool
marsh marshal.Marshalizer
hasher hashing.Hasher
}
type branchNode struct {
CollapsedBn
children [nrOfChildren]node
*baseNode
}
type extensionNode struct {
CollapsedEn
child node
*baseNode
}
type leafNode struct {
CollapsedLn
*baseNode
}
func hashChildrenAndNode(n node) ([]byte, error) {
err := n.hashChildren()
if err != nil {
return nil, err
}
hashed, err := n.hashNode()
if err != nil {
return nil, err
}
return hashed, nil
}
func encodeNodeAndGetHash(n node) ([]byte, error) {
encNode, err := n.getEncodedNode()
if err != nil {
return nil, err
}
hash := n.getHasher().Compute(string(encNode))
return hash, nil
}
// encodeNodeAndCommitToDB will encode and save provided node. It returns the node's value in bytes
func encodeNodeAndCommitToDB(n node, db common.DBWriteCacher) (int, error) {
key, err := computeAndSetNodeHash(n)
if err != nil {
return 0, err
}
n, err = n.getCollapsed()
if err != nil {
return 0, err
}
val, err := n.getEncodedNode()
if err != nil {
return 0, err
}
// test point encodeNodeAndCommitToDB
err = db.Put(key, val)
return len(val), err
}
func computeAndSetNodeHash(n node) ([]byte, error) {
key := n.getHash()
if len(key) != 0 {
return key, nil
}
err := n.setHash()
if err != nil {
return nil, err
}
key = n.getHash()
return key, nil
}
func getNodeFromDBAndDecode(n []byte, db common.DBWriteCacher, marshalizer marshal.Marshalizer, hasher hashing.Hasher) (node, error) {
encChild, err := db.Get(n)
if err != nil {
log.Trace(common.GetNodeFromDBErrorString, "error", err, "key", n)
return nil, fmt.Errorf(common.GetNodeFromDBErrorString+" %w for key %v", err, hex.EncodeToString(n))
}
decodedNode, err := decodeNode(encChild, marshalizer, hasher)
if err != nil {
return nil, err
}
return decodedNode, nil
}
func resolveIfCollapsed(n node, pos byte, db common.DBWriteCacher) error {
err := n.isEmptyOrNil()
if err != nil {
return err
}
if n.isPosCollapsed(int(pos)) {
err = n.resolveCollapsed(pos, db)
if err != nil {
return err
}
}
return nil
}
func concat(s1 []byte, s2 ...byte) []byte {
r := make([]byte, len(s1)+len(s2))
copy(r, s1)
copy(r[len(s1):], s2)
return r
}
func hasValidHash(n node) (bool, error) {
err := n.isEmptyOrNil()
if err != nil {
return false, err
}
childHash := n.getHash()
childIsDirty := n.isDirty()
if childHash == nil || childIsDirty {
return false, nil
}
return true, nil
}
func decodeNode(encNode []byte, marshalizer marshal.Marshalizer, hasher hashing.Hasher) (node, error) {
if encNode == nil || len(encNode) < 1 {
return nil, ErrInvalidEncoding
}
nodeType := encNode[len(encNode)-1]
encNode = encNode[:len(encNode)-1]
newNode, err := getEmptyNodeOfType(nodeType)
if err != nil {
return nil, err
}
err = marshalizer.Unmarshal(newNode, encNode)
if err != nil {
return nil, err
}
newNode.setMarshalizer(marshalizer)
newNode.setHasher(hasher)
return newNode, nil
}
func getEmptyNodeOfType(t byte) (node, error) {
switch t {
case extension:
return &extensionNode{baseNode: &baseNode{}}, nil
case leaf:
return &leafNode{baseNode: &baseNode{}}, nil
case branch:
return &branchNode{baseNode: &baseNode{}}, nil
default:
return nil, ErrInvalidNode
}
}
func childPosOutOfRange(pos byte) bool {
return pos >= nrOfChildren
}
// keyBytesToHex transforms key bytes into hex nibbles. The key nibbles are reversed, meaning that the
// last key nibble will be the first in the hex key. A hex terminator is added at the end of the hex key.
func keyBytesToHex(str []byte) []byte {
hexLength := len(str)*2 + 1
nibbles := make([]byte, hexLength)
hexSliceIndex := 0
nibbles[hexLength-1] = hexTerminator
for i := hexLength - 2; i > 0; i -= 2 {
nibbles[i] = str[hexSliceIndex] >> nibbleSize
nibbles[i-1] = str[hexSliceIndex] & nibbleMask
hexSliceIndex++
}
return nibbles
}
// hexToKeyBytes transforms hex nibbles into key bytes. The hex terminator is removed from the end of the hex slice,
// and then the hex slice is reversed when forming the key bytes.
func hexToKeyBytes(hex []byte) ([]byte, error) {
hex = hex[:len(hex)-1]
length := len(hex)
if length%2 != 0 {
return nil, ErrInvalidLength
}
key := make([]byte, length/2)
hexSliceIndex := 0
for i := len(key) - 1; i >= 0; i-- {
key[i] = hex[hexSliceIndex+1]<<nibbleSize | hex[hexSliceIndex]
hexSliceIndex += 2
}
return key, nil
}
// prefixLen returns the length of the common prefix of a and b.
func prefixLen(a, b []byte) int {
i := 0
length := len(a)
if len(b) < length {
length = len(b)
}
for ; i < length; i++ {
if a[i] != b[i] {
break
}
}
return i
}
func shouldStopIfContextDone(ctx context.Context, idleProvider IdleNodeProvider) bool {
for {
select {
case <-ctx.Done():
return true
default:
}
if idleProvider.IsIdle() {
return false
}
select {
case <-ctx.Done():
return true
case <-time.After(pollingIdleNode):
}
}
}