// Copyright 2017 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 downloader
import (
"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/ethdb"
)
// FakePeer is a mock downloader peer that operates on a local database instance
// instead of being an actual live node. It's useful for testing and to implement
// sync commands from an xisting local database.
type FakePeer struct {
id string
db ethdb.Database
hc *core.HeaderChain
dl *Downloader
}
// NewFakePeer creates a new mock downloader peer with the given data sources.
func NewFakePeer(id string, db ethdb.Database, hc *core.HeaderChain, dl *Downloader) *FakePeer {
return &FakePeer{id: id, db: db, hc: hc, dl: dl}
}
// Head implements downloader.Peer, returning the current head hash and number
// of the best known header.
func (p *FakePeer) Head() (common.Hash, *big.Int) {
header := p.hc.CurrentHeader()
return header.Hash(), header.Number
}
// RequestHeadersByHash implements downloader.Peer, returning a batch of headers
// defined by the origin hash and the associaed query parameters.
func (p *FakePeer) RequestHeadersByHash(hash common.Hash, amount int, skip int, reverse bool) error {
var (
headers []*types.Header
unknown bool
)
for !unknown && len(headers) < amount {
origin := p.hc.GetHeaderByHash(hash)
if origin == nil {
break
}
number := origin.Number.Uint64()
headers = append(headers, origin)
if reverse {
for i := 0; i < int(skip)+1; i++ {
if header := p.hc.GetHeader(hash, number); header != nil {
hash = header.ParentHash
number--
} else {
unknown = true
break
}
}
} else {
var (
current = origin.Number.Uint64()
next = current + uint64(skip) + 1
)
if header := p.hc.GetHeaderByNumber(next); header != nil {
if p.hc.GetBlockHashesFromHash(header.Hash(), uint64(skip+1))[skip] == hash {
hash = header.Hash()
} else {
unknown = true
}
} else {
unknown = true
}
}
}
p.dl.DeliverHeaders(p.id, headers)
return nil
}
// RequestHeadersByNumber implements downloader.Peer, returning a batch of headers
// defined by the origin number and the associaed query parameters.
func (p *FakePeer) RequestHeadersByNumber(number uint64, amount int, skip int, reverse bool) error {
var (
headers []*types.Header
unknown bool
)
for !unknown && len(headers) < amount {
origin := p.hc.GetHeaderByNumber(number)
if origin == nil {
break
}
if reverse {
if number >= uint64(skip+1) {
number -= uint64(skip + 1)
} else {
unknown = true
}
} else {
number += uint64(skip + 1)
}
headers = append(headers, origin)
}
p.dl.DeliverHeaders(p.id, headers)
return nil
}
// RequestBodies implements downloader.Peer, returning a batch of block bodies
// corresponding to the specified block hashes.
func (p *FakePeer) RequestBodies(hashes []common.Hash) error {
var (
txs [][]*types.Transaction
uncles [][]*types.Header
)
for _, hash := range hashes {
block := core.GetBlock(p.db, hash, p.hc.GetBlockNumber(hash))
txs = append(txs, block.Transactions())
uncles = append(uncles, block.Uncles())
}
p.dl.DeliverBodies(p.id, txs, uncles)
return nil
}
// RequestReceipts implements downloader.Peer, returning a batch of transaction
// receipts corresponding to the specified block hashes.
func (p *FakePeer) RequestReceipts(hashes []common.Hash) error {
var receipts [][]*types.Receipt
for _, hash := range hashes {
receipts = append(receipts, core.GetBlockReceipts(p.db, hash, p.hc.GetBlockNumber(hash)))
}
p.dl.DeliverReceipts(p.id, receipts)
return nil
}
// RequestNodeData implements downloader.Peer, returning a batch of state trie
// nodes corresponding to the specified trie hashes.
func (p *FakePeer) RequestNodeData(hashes []common.Hash) error {
var data [][]byte
for _, hash := range hashes {
if entry, err := p.db.Get(hash.Bytes()); err == nil {
data = append(data, entry)
}
}
p.dl.DeliverNodeData(p.id, data)
return nil
}