cmd, eth: separate out FakePeer for future reuse

1 files changed, 160 insertions, 0 deletions

diff --git a/eth/downloader/fakepeer.go b/eth/downloader/fakepeer.go
new file mode 100644
index 000000000..ebdb9c334
--- /dev/null
+++ b/eth/downloader/fakepeer.go
@@ -0,0 +1,160 @@
+// 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
+}