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// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package light
import (
"bytes"
"errors"
"math/big"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/rlp"
"golang.org/x/net/context"
)
var sha3_nil = crypto.Keccak256Hash(nil)
var (
ErrNoTrustedCht = errors.New("No trusted canonical hash trie")
ErrNoHeader = errors.New("Header not found")
ChtFrequency = uint64(4096)
ChtConfirmations = uint64(2048)
trustedChtKey = []byte("TrustedCHT")
)
type ChtNode struct {
Hash common.Hash
Td *big.Int
}
type TrustedCht struct {
Number uint64
Root common.Hash
}
func GetTrustedCht(db ethdb.Database) TrustedCht {
data, _ := db.Get(trustedChtKey)
var res TrustedCht
if err := rlp.DecodeBytes(data, &res); err != nil {
return TrustedCht{0, common.Hash{}}
}
return res
}
func WriteTrustedCht(db ethdb.Database, cht TrustedCht) {
data, _ := rlp.EncodeToBytes(cht)
db.Put(trustedChtKey, data)
}
func DeleteTrustedCht(db ethdb.Database) {
db.Delete(trustedChtKey)
}
func GetHeaderByNumber(ctx context.Context, odr OdrBackend, number uint64) (*types.Header, error) {
db := odr.Database()
hash := core.GetCanonicalHash(db, number)
if (hash != common.Hash{}) {
// if there is a canonical hash, there is a header too
header := core.GetHeader(db, hash, number)
if header == nil {
panic("Canonical hash present but header not found")
}
return header, nil
}
cht := GetTrustedCht(db)
if number >= cht.Number*ChtFrequency {
return nil, ErrNoTrustedCht
}
r := &ChtRequest{ChtRoot: cht.Root, ChtNum: cht.Number, BlockNum: number}
if err := odr.Retrieve(ctx, r); err != nil {
return nil, err
} else {
return r.Header, nil
}
}
func GetCanonicalHash(ctx context.Context, odr OdrBackend, number uint64) (common.Hash, error) {
hash := core.GetCanonicalHash(odr.Database(), number)
if (hash != common.Hash{}) {
return hash, nil
}
header, err := GetHeaderByNumber(ctx, odr, number)
if header != nil {
return header.Hash(), nil
}
return common.Hash{}, err
}
// retrieveContractCode tries to retrieve the contract code of the given account
// with the given hash from the network (id points to the storage trie belonging
// to the same account)
func retrieveContractCode(ctx context.Context, odr OdrBackend, id *TrieID, hash common.Hash) ([]byte, error) {
if hash == sha3_nil {
return nil, nil
}
res, _ := odr.Database().Get(hash[:])
if res != nil {
return res, nil
}
r := &CodeRequest{Id: id, Hash: hash}
if err := odr.Retrieve(ctx, r); err != nil {
return nil, err
} else {
return r.Data, nil
}
}
// GetBodyRLP retrieves the block body (transactions and uncles) in RLP encoding.
func GetBodyRLP(ctx context.Context, odr OdrBackend, hash common.Hash, number uint64) (rlp.RawValue, error) {
if data := core.GetBodyRLP(odr.Database(), hash, number); data != nil {
return data, nil
}
r := &BlockRequest{Hash: hash, Number: number}
if err := odr.Retrieve(ctx, r); err != nil {
return nil, err
} else {
return r.Rlp, nil
}
}
// GetBody retrieves the block body (transactons, uncles) corresponding to the
// hash.
func GetBody(ctx context.Context, odr OdrBackend, hash common.Hash, number uint64) (*types.Body, error) {
data, err := GetBodyRLP(ctx, odr, hash, number)
if err != nil {
return nil, err
}
body := new(types.Body)
if err := rlp.Decode(bytes.NewReader(data), body); err != nil {
return nil, err
}
return body, nil
}
// GetBlock retrieves an entire block corresponding to the hash, assembling it
// back from the stored header and body.
func GetBlock(ctx context.Context, odr OdrBackend, hash common.Hash, number uint64) (*types.Block, error) {
// Retrieve the block header and body contents
header := core.GetHeader(odr.Database(), hash, number)
if header == nil {
return nil, ErrNoHeader
}
body, err := GetBody(ctx, odr, hash, number)
if err != nil {
return nil, err
}
// Reassemble the block and return
return types.NewBlockWithHeader(header).WithBody(body.Transactions, body.Uncles), nil
}
// GetBlockReceipts retrieves the receipts generated by the transactions included
// in a block given by its hash.
func GetBlockReceipts(ctx context.Context, odr OdrBackend, hash common.Hash, number uint64) (types.Receipts, error) {
receipts := core.GetBlockReceipts(odr.Database(), hash, number)
if receipts != nil {
return receipts, nil
}
r := &ReceiptsRequest{Hash: hash, Number: number}
if err := odr.Retrieve(ctx, r); err != nil {
return nil, err
}
return r.Receipts, nil
}
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