135 lines
4.3 KiB
Go
135 lines
4.3 KiB
Go
// Copyright 2021 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package types
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import (
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"bytes"
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"fmt"
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"math"
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"sync"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/crypto"
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"github.com/ethereum/go-ethereum/rlp"
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"golang.org/x/crypto/sha3"
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)
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// hasherPool holds LegacyKeccak256 hashers for rlpHash.
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var hasherPool = sync.Pool{
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New: func() interface{} { return sha3.NewLegacyKeccak256() },
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}
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// encodeBufferPool holds temporary encoder buffers for DeriveSha and TX encoding.
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var encodeBufferPool = sync.Pool{
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New: func() interface{} { return new(bytes.Buffer) },
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}
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// getPooledBuffer retrieves a buffer from the pool and creates a byte slice of the
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// requested size from it.
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//
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// The caller should return the *bytes.Buffer object back into encodeBufferPool after use!
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// The returned byte slice must not be used after returning the buffer.
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func getPooledBuffer(size uint64) ([]byte, *bytes.Buffer, error) {
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if size > math.MaxInt {
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return nil, nil, fmt.Errorf("can't get buffer of size %d", size)
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}
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buf := encodeBufferPool.Get().(*bytes.Buffer)
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buf.Reset()
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buf.Grow(int(size))
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b := buf.Bytes()[:int(size)]
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return b, buf, nil
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}
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// rlpHash encodes x and hashes the encoded bytes.
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func rlpHash(x interface{}) (h common.Hash) {
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sha := hasherPool.Get().(crypto.KeccakState)
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defer hasherPool.Put(sha)
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sha.Reset()
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rlp.Encode(sha, x)
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sha.Read(h[:])
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return h
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}
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// prefixedRlpHash writes the prefix into the hasher before rlp-encoding x.
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// It's used for typed transactions.
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func prefixedRlpHash(prefix byte, x interface{}) (h common.Hash) {
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sha := hasherPool.Get().(crypto.KeccakState)
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defer hasherPool.Put(sha)
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sha.Reset()
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sha.Write([]byte{prefix})
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rlp.Encode(sha, x)
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sha.Read(h[:])
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return h
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}
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// TrieHasher is the tool used to calculate the hash of derivable list.
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// This is internal, do not use.
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type TrieHasher interface {
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Reset()
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Update([]byte, []byte) error
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Hash() common.Hash
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}
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// DerivableList is the input to DeriveSha.
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// It is implemented by the 'Transactions' and 'Receipts' types.
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// This is internal, do not use these methods.
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type DerivableList interface {
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Len() int
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EncodeIndex(int, *bytes.Buffer)
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}
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func encodeForDerive(list DerivableList, i int, buf *bytes.Buffer) []byte {
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buf.Reset()
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list.EncodeIndex(i, buf)
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// It's really unfortunate that we need to perform this copy.
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// StackTrie holds onto the values until Hash is called, so the values
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// written to it must not alias.
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return common.CopyBytes(buf.Bytes())
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}
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// DeriveSha creates the tree hashes of transactions, receipts, and withdrawals in a block header.
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func DeriveSha(list DerivableList, hasher TrieHasher) common.Hash {
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hasher.Reset()
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valueBuf := encodeBufferPool.Get().(*bytes.Buffer)
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defer encodeBufferPool.Put(valueBuf)
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// StackTrie requires values to be inserted in increasing hash order, which is not the
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// order that `list` provides hashes in. This insertion sequence ensures that the
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// order is correct.
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//
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// The error returned by hasher is omitted because hasher will produce an incorrect
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// hash in case any error occurs.
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var indexBuf []byte
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for i := 1; i < list.Len() && i <= 0x7f; i++ {
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indexBuf = rlp.AppendUint64(indexBuf[:0], uint64(i))
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value := encodeForDerive(list, i, valueBuf)
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hasher.Update(indexBuf, value)
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}
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if list.Len() > 0 {
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indexBuf = rlp.AppendUint64(indexBuf[:0], 0)
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value := encodeForDerive(list, 0, valueBuf)
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hasher.Update(indexBuf, value)
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}
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for i := 0x80; i < list.Len(); i++ {
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indexBuf = rlp.AppendUint64(indexBuf[:0], uint64(i))
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value := encodeForDerive(list, i, valueBuf)
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hasher.Update(indexBuf, value)
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}
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return hasher.Hash()
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}
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