trie: rework and document key encoding
'encode' and 'decode' are meaningless because the code deals with three encodings. Document the encodings and give a name to each one.
This commit is contained in:
Felix Lange
Родитель
a31d268b76
Коммит
f958d7d482
114
trie/encoding.go
114
trie/encoding.go
|
|
@ -16,49 +16,54 @@
|
|||
|
||||
package trie
|
||||
|
||||
func compactEncode(hexSlice []byte) []byte {
|
||||
// Trie keys are dealt with in three distinct encodings:
|
||||
//
|
||||
// KEYBYTES encoding contains the actual key and nothing else. This encoding is the
|
||||
// input to most API functions.
|
||||
//
|
||||
// HEX encoding contains one byte for each nibble of the key and an optional trailing
|
||||
// 'terminator' byte of value 0x10 which indicates whether or not the node at the key
|
||||
// contains a value. Hex key encoding is used for nodes loaded in memory because it's
|
||||
// convenient to access.
|
||||
//
|
||||
// COMPACT encoding is defined by the Ethereum Yellow Paper (it's called "hex prefix
|
||||
// encoding" there) and contains the bytes of the key and a flag. The high nibble of the
|
||||
// first byte contains the flag; the lowest bit encoding the oddness of the length and
|
||||
// the second-lowest encoding whether the node at the key is a value node. The low nibble
|
||||
// of the first byte is zero in the case of an even number of nibbles and the first nibble
|
||||
// in the case of an odd number. All remaining nibbles (now an even number) fit properly
|
||||
// into the remaining bytes. Compact encoding is used for nodes stored on disk.
|
||||
|
||||
func hexToCompact(hex []byte) []byte {
|
||||
terminator := byte(0)
|
||||
if hexSlice[len(hexSlice)-1] == 16 {
|
||||
if hasTerm(hex) {
|
||||
terminator = 1
|
||||
hexSlice = hexSlice[:len(hexSlice)-1]
|
||||
hex = hex[:len(hex)-1]
|
||||
}
|
||||
var (
|
||||
odd = byte(len(hexSlice) % 2)
|
||||
buflen = len(hexSlice)/2 + 1
|
||||
bi, hi = 0, 0 // indices
|
||||
hs = byte(0) // shift: flips between 0 and 4
|
||||
)
|
||||
if odd == 0 {
|
||||
bi = 1
|
||||
hs = 4
|
||||
}
|
||||
buf := make([]byte, buflen)
|
||||
buf[0] = terminator<<5 | byte(odd)<<4
|
||||
for bi < len(buf) && hi < len(hexSlice) {
|
||||
buf[bi] |= hexSlice[hi] << hs
|
||||
if hs == 0 {
|
||||
bi++
|
||||
}
|
||||
hi, hs = hi+1, hs^(1<<2)
|
||||
buf := make([]byte, len(hex)/2+1)
|
||||
buf[0] = terminator << 5 // the flag byte
|
||||
if len(hex)&1 == 1 {
|
||||
buf[0] |= 1 << 4 // odd flag
|
||||
buf[0] |= hex[0] // first nibble is contained in the first byte
|
||||
hex = hex[1:]
|
||||
}
|
||||
decodeNibbles(hex, buf[1:])
|
||||
return buf
|
||||
}
|
||||
|
||||
func compactDecode(str []byte) []byte {
|
||||
base := compactHexDecode(str)
|
||||
func compactToHex(compact []byte) []byte {
|
||||
base := keybytesToHex(compact)
|
||||
base = base[:len(base)-1]
|
||||
// apply terminator flag
|
||||
if base[0] >= 2 {
|
||||
base = append(base, 16)
|
||||
}
|
||||
if base[0]%2 == 1 {
|
||||
base = base[1:]
|
||||
} else {
|
||||
base = base[2:]
|
||||
}
|
||||
return base
|
||||
// apply odd flag
|
||||
chop := 2 - base[0]&1
|
||||
return base[chop:]
|
||||
}
|
||||
|
||||
func compactHexDecode(str []byte) []byte {
|
||||
func keybytesToHex(str []byte) []byte {
|
||||
l := len(str)*2 + 1
|
||||
var nibbles = make([]byte, l)
|
||||
for i, b := range str {
|
||||
|
|
@ -69,35 +74,24 @@ func compactHexDecode(str []byte) []byte {
|
|||
return nibbles
|
||||
}
|
||||
|
||||
// compactHexEncode encodes a series of nibbles into a byte array
|
||||
func compactHexEncode(nibbles []byte) []byte {
|
||||
nl := len(nibbles)
|
||||
if nl == 0 {
|
||||
return nil
|
||||
// hexToKeybytes turns hex nibbles into key bytes.
|
||||
// This can only be used for keys of even length.
|
||||
func hexToKeybytes(hex []byte) []byte {
|
||||
if hasTerm(hex) {
|
||||
hex = hex[:len(hex)-1]
|
||||
}
|
||||
if nibbles[nl-1] == 16 {
|
||||
nl--
|
||||
if len(hex)&1 != 0 {
|
||||
panic("can't convert hex key of odd length")
|
||||
}
|
||||
l := (nl + 1) / 2
|
||||
var str = make([]byte, l)
|
||||
for i := range str {
|
||||
b := nibbles[i*2] * 16
|
||||
if nl > i*2 {
|
||||
b += nibbles[i*2+1]
|
||||
}
|
||||
str[i] = b
|
||||
}
|
||||
return str
|
||||
key := make([]byte, (len(hex)+1)/2)
|
||||
decodeNibbles(hex, key)
|
||||
return key
|
||||
}
|
||||
|
||||
func decodeCompact(key []byte) []byte {
|
||||
l := len(key) / 2
|
||||
var res = make([]byte, l)
|
||||
for i := 0; i < l; i++ {
|
||||
v1, v0 := key[2*i], key[2*i+1]
|
||||
res[i] = v1*16 + v0
|
||||
func decodeNibbles(nibbles []byte, bytes []byte) {
|
||||
for bi, ni := 0, 0; ni < len(nibbles); bi, ni = bi+1, ni+2 {
|
||||
bytes[bi] = nibbles[ni]<<4 | nibbles[ni+1]
|
||||
}
|
||||
return res
|
||||
}
|
||||
|
||||
// prefixLen returns the length of the common prefix of a and b.
|
||||
|
|
@ -114,15 +108,7 @@ func prefixLen(a, b []byte) int {
|
|||
return i
|
||||
}
|
||||
|
||||
// hasTerm returns whether a hex key has the terminator flag.
|
||||
func hasTerm(s []byte) bool {
|
||||
return s[len(s)-1] == 16
|
||||
}
|
||||
|
||||
func remTerm(s []byte) []byte {
|
||||
if hasTerm(s) {
|
||||
b := make([]byte, len(s)-1)
|
||||
copy(b, s)
|
||||
return b
|
||||
}
|
||||
return s
|
||||
return len(s) > 0 && s[len(s)-1] == 16
|
||||
}
|
||||
|
|
|
|||
|
|
@ -17,113 +17,88 @@
|
|||
package trie
|
||||
|
||||
import (
|
||||
"encoding/hex"
|
||||
"bytes"
|
||||
"testing"
|
||||
|
||||
checker "gopkg.in/check.v1"
|
||||
)
|
||||
|
||||
func TestEncoding(t *testing.T) { checker.TestingT(t) }
|
||||
|
||||
type TrieEncodingSuite struct{}
|
||||
|
||||
var _ = checker.Suite(&TrieEncodingSuite{})
|
||||
|
||||
func (s *TrieEncodingSuite) TestCompactEncode(c *checker.C) {
|
||||
// even compact encode
|
||||
test1 := []byte{1, 2, 3, 4, 5}
|
||||
res1 := compactEncode(test1)
|
||||
c.Assert(res1, checker.DeepEquals, []byte("\x11\x23\x45"))
|
||||
|
||||
// odd compact encode
|
||||
test2 := []byte{0, 1, 2, 3, 4, 5}
|
||||
res2 := compactEncode(test2)
|
||||
c.Assert(res2, checker.DeepEquals, []byte("\x00\x01\x23\x45"))
|
||||
|
||||
//odd terminated compact encode
|
||||
test3 := []byte{0, 15, 1, 12, 11, 8 /*term*/, 16}
|
||||
res3 := compactEncode(test3)
|
||||
c.Assert(res3, checker.DeepEquals, []byte("\x20\x0f\x1c\xb8"))
|
||||
|
||||
// even terminated compact encode
|
||||
test4 := []byte{15, 1, 12, 11, 8 /*term*/, 16}
|
||||
res4 := compactEncode(test4)
|
||||
c.Assert(res4, checker.DeepEquals, []byte("\x3f\x1c\xb8"))
|
||||
}
|
||||
|
||||
func (s *TrieEncodingSuite) TestCompactHexDecode(c *checker.C) {
|
||||
exp := []byte{7, 6, 6, 5, 7, 2, 6, 2, 16}
|
||||
res := compactHexDecode([]byte("verb"))
|
||||
c.Assert(res, checker.DeepEquals, exp)
|
||||
}
|
||||
|
||||
func (s *TrieEncodingSuite) TestCompactHexEncode(c *checker.C) {
|
||||
exp := []byte("verb")
|
||||
res := compactHexEncode([]byte{7, 6, 6, 5, 7, 2, 6, 2, 16})
|
||||
c.Assert(res, checker.DeepEquals, exp)
|
||||
}
|
||||
|
||||
func (s *TrieEncodingSuite) TestCompactDecode(c *checker.C) {
|
||||
// odd compact decode
|
||||
exp := []byte{1, 2, 3, 4, 5}
|
||||
res := compactDecode([]byte("\x11\x23\x45"))
|
||||
c.Assert(res, checker.DeepEquals, exp)
|
||||
|
||||
// even compact decode
|
||||
exp = []byte{0, 1, 2, 3, 4, 5}
|
||||
res = compactDecode([]byte("\x00\x01\x23\x45"))
|
||||
c.Assert(res, checker.DeepEquals, exp)
|
||||
|
||||
// even terminated compact decode
|
||||
exp = []byte{0, 15, 1, 12, 11, 8 /*term*/, 16}
|
||||
res = compactDecode([]byte("\x20\x0f\x1c\xb8"))
|
||||
c.Assert(res, checker.DeepEquals, exp)
|
||||
|
||||
// even terminated compact decode
|
||||
exp = []byte{15, 1, 12, 11, 8 /*term*/, 16}
|
||||
res = compactDecode([]byte("\x3f\x1c\xb8"))
|
||||
c.Assert(res, checker.DeepEquals, exp)
|
||||
}
|
||||
|
||||
func (s *TrieEncodingSuite) TestDecodeCompact(c *checker.C) {
|
||||
exp, _ := hex.DecodeString("012345")
|
||||
res := decodeCompact([]byte{0, 1, 2, 3, 4, 5})
|
||||
c.Assert(res, checker.DeepEquals, exp)
|
||||
|
||||
exp, _ = hex.DecodeString("012345")
|
||||
res = decodeCompact([]byte{0, 1, 2, 3, 4, 5, 16})
|
||||
c.Assert(res, checker.DeepEquals, exp)
|
||||
|
||||
exp, _ = hex.DecodeString("abcdef")
|
||||
res = decodeCompact([]byte{10, 11, 12, 13, 14, 15})
|
||||
c.Assert(res, checker.DeepEquals, exp)
|
||||
}
|
||||
|
||||
func BenchmarkCompactEncode(b *testing.B) {
|
||||
|
||||
testBytes := []byte{0, 15, 1, 12, 11, 8 /*term*/, 16}
|
||||
for i := 0; i < b.N; i++ {
|
||||
compactEncode(testBytes)
|
||||
func TestHexCompact(t *testing.T) {
|
||||
tests := []struct{ hex, compact []byte }{
|
||||
// empty keys, with and without terminator.
|
||||
{hex: []byte{}, compact: []byte{0x00}},
|
||||
{hex: []byte{16}, compact: []byte{0x20}},
|
||||
// odd length, no terminator
|
||||
{hex: []byte{1, 2, 3, 4, 5}, compact: []byte{0x11, 0x23, 0x45}},
|
||||
// even length, no terminator
|
||||
{hex: []byte{0, 1, 2, 3, 4, 5}, compact: []byte{0x00, 0x01, 0x23, 0x45}},
|
||||
// odd length, terminator
|
||||
{hex: []byte{15, 1, 12, 11, 8, 16 /*term*/}, compact: []byte{0x3f, 0x1c, 0xb8}},
|
||||
// even length, terminator
|
||||
{hex: []byte{0, 15, 1, 12, 11, 8, 16 /*term*/}, compact: []byte{0x20, 0x0f, 0x1c, 0xb8}},
|
||||
}
|
||||
for _, test := range tests {
|
||||
if c := hexToCompact(test.hex); !bytes.Equal(c, test.compact) {
|
||||
t.Errorf("hexToCompact(%x) -> %x, want %x", test.hex, c, test.compact)
|
||||
}
|
||||
if h := compactToHex(test.compact); !bytes.Equal(h, test.hex) {
|
||||
t.Errorf("compactToHex(%x) -> %x, want %x", test.compact, h, test.hex)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func BenchmarkCompactDecode(b *testing.B) {
|
||||
testBytes := []byte{0, 15, 1, 12, 11, 8 /*term*/, 16}
|
||||
for i := 0; i < b.N; i++ {
|
||||
compactDecode(testBytes)
|
||||
func TestHexKeybytes(t *testing.T) {
|
||||
tests := []struct{ key, hexIn, hexOut []byte }{
|
||||
{key: []byte{}, hexIn: []byte{16}, hexOut: []byte{16}},
|
||||
{key: []byte{}, hexIn: []byte{}, hexOut: []byte{16}},
|
||||
{
|
||||
key: []byte{0x12, 0x34, 0x56},
|
||||
hexIn: []byte{1, 2, 3, 4, 5, 6, 16},
|
||||
hexOut: []byte{1, 2, 3, 4, 5, 6, 16},
|
||||
},
|
||||
{
|
||||
key: []byte{0x12, 0x34, 0x5},
|
||||
hexIn: []byte{1, 2, 3, 4, 0, 5, 16},
|
||||
hexOut: []byte{1, 2, 3, 4, 0, 5, 16},
|
||||
},
|
||||
{
|
||||
key: []byte{0x12, 0x34, 0x56},
|
||||
hexIn: []byte{1, 2, 3, 4, 5, 6},
|
||||
hexOut: []byte{1, 2, 3, 4, 5, 6, 16},
|
||||
},
|
||||
}
|
||||
for _, test := range tests {
|
||||
if h := keybytesToHex(test.key); !bytes.Equal(h, test.hexOut) {
|
||||
t.Errorf("keybytesToHex(%x) -> %x, want %x", test.key, h, test.hexOut)
|
||||
}
|
||||
if k := hexToKeybytes(test.hexIn); !bytes.Equal(k, test.key) {
|
||||
t.Errorf("hexToKeybytes(%x) -> %x, want %x", test.hexIn, k, test.key)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func BenchmarkCompactHexDecode(b *testing.B) {
|
||||
func BenchmarkHexToCompact(b *testing.B) {
|
||||
testBytes := []byte{0, 15, 1, 12, 11, 8, 16 /*term*/}
|
||||
for i := 0; i < b.N; i++ {
|
||||
hexToCompact(testBytes)
|
||||
}
|
||||
}
|
||||
|
||||
func BenchmarkCompactToHex(b *testing.B) {
|
||||
testBytes := []byte{0, 15, 1, 12, 11, 8, 16 /*term*/}
|
||||
for i := 0; i < b.N; i++ {
|
||||
compactToHex(testBytes)
|
||||
}
|
||||
}
|
||||
|
||||
func BenchmarkKeybytesToHex(b *testing.B) {
|
||||
testBytes := []byte{7, 6, 6, 5, 7, 2, 6, 2, 16}
|
||||
for i := 0; i < b.N; i++ {
|
||||
compactHexDecode(testBytes)
|
||||
keybytesToHex(testBytes)
|
||||
}
|
||||
}
|
||||
|
||||
func BenchmarkDecodeCompact(b *testing.B) {
|
||||
func BenchmarkHexToKeybytes(b *testing.B) {
|
||||
testBytes := []byte{7, 6, 6, 5, 7, 2, 6, 2, 16}
|
||||
for i := 0; i < b.N; i++ {
|
||||
decodeCompact(testBytes)
|
||||
hexToKeybytes(testBytes)
|
||||
}
|
||||
}
|
||||
|
|
|
|||
|
|
@ -105,7 +105,7 @@ func (h *hasher) hashChildren(original node, db DatabaseWriter) (node, node, err
|
|||
case *shortNode:
|
||||
// Hash the short node's child, caching the newly hashed subtree
|
||||
collapsed, cached := n.copy(), n.copy()
|
||||
collapsed.Key = compactEncode(n.Key)
|
||||
collapsed.Key = hexToCompact(n.Key)
|
||||
cached.Key = common.CopyBytes(n.Key)
|
||||
|
||||
if _, ok := n.Val.(valueNode); !ok {
|
||||
|
|
|
|||
|
|
@ -19,6 +19,7 @@ package trie
|
|||
import (
|
||||
"bytes"
|
||||
"container/heap"
|
||||
|
||||
"github.com/ethereum/go-ethereum/common"
|
||||
)
|
||||
|
||||
|
|
@ -48,7 +49,7 @@ func NewIteratorFromNodeIterator(it NodeIterator) *Iterator {
|
|||
func (it *Iterator) Next() bool {
|
||||
for it.nodeIt.Next(true) {
|
||||
if it.nodeIt.Leaf() {
|
||||
it.Key = decodeCompact(it.nodeIt.Path())
|
||||
it.Key = hexToKeybytes(it.nodeIt.Path())
|
||||
it.Value = it.nodeIt.LeafBlob()
|
||||
return true
|
||||
}
|
||||
|
|
|
|||
|
|
@ -139,8 +139,8 @@ func decodeShort(hash, buf, elems []byte, cachegen uint16) (node, error) {
|
|||
return nil, err
|
||||
}
|
||||
flag := nodeFlag{hash: hash, gen: cachegen}
|
||||
key := compactDecode(kbuf)
|
||||
if key[len(key)-1] == 16 {
|
||||
key := compactToHex(kbuf)
|
||||
if hasTerm(key) {
|
||||
// value node
|
||||
val, _, err := rlp.SplitString(rest)
|
||||
if err != nil {
|
||||
|
|
|
|||
|
|
@ -38,7 +38,7 @@ import (
|
|||
// absence of the key.
|
||||
func (t *Trie) Prove(key []byte) []rlp.RawValue {
|
||||
// Collect all nodes on the path to key.
|
||||
key = compactHexDecode(key)
|
||||
key = keybytesToHex(key)
|
||||
nodes := []node{}
|
||||
tn := t.root
|
||||
for len(key) > 0 && tn != nil {
|
||||
|
|
@ -89,7 +89,7 @@ func (t *Trie) Prove(key []byte) []rlp.RawValue {
|
|||
// returns an error if the proof contains invalid trie nodes or the
|
||||
// wrong value.
|
||||
func VerifyProof(rootHash common.Hash, key []byte, proof []rlp.RawValue) (value []byte, err error) {
|
||||
key = compactHexDecode(key)
|
||||
key = keybytesToHex(key)
|
||||
sha := sha3.NewKeccak256()
|
||||
wantHash := rootHash.Bytes()
|
||||
for i, buf := range proof {
|
||||
|
|
|
|||
|
|
@ -144,7 +144,7 @@ func (t *Trie) Get(key []byte) []byte {
|
|||
// The value bytes must not be modified by the caller.
|
||||
// If a node was not found in the database, a MissingNodeError is returned.
|
||||
func (t *Trie) TryGet(key []byte) ([]byte, error) {
|
||||
key = compactHexDecode(key)
|
||||
key = keybytesToHex(key)
|
||||
value, newroot, didResolve, err := t.tryGet(t.root, key, 0)
|
||||
if err == nil && didResolve {
|
||||
t.root = newroot
|
||||
|
|
@ -211,7 +211,7 @@ func (t *Trie) Update(key, value []byte) {
|
|||
//
|
||||
// If a node was not found in the database, a MissingNodeError is returned.
|
||||
func (t *Trie) TryUpdate(key, value []byte) error {
|
||||
k := compactHexDecode(key)
|
||||
k := keybytesToHex(key)
|
||||
if len(value) != 0 {
|
||||
_, n, err := t.insert(t.root, nil, k, valueNode(value))
|
||||
if err != nil {
|
||||
|
|
@ -307,7 +307,7 @@ func (t *Trie) Delete(key []byte) {
|
|||
// TryDelete removes any existing value for key from the trie.
|
||||
// If a node was not found in the database, a MissingNodeError is returned.
|
||||
func (t *Trie) TryDelete(key []byte) error {
|
||||
k := compactHexDecode(key)
|
||||
k := keybytesToHex(key)
|
||||
_, n, err := t.delete(t.root, nil, k)
|
||||
if err != nil {
|
||||
return err
|
||||
|
|
|
|||
Загрузка…
Ссылка в новой задаче