cmd, eth: separate out FakePeer for future reuse

3 files changed, 192 insertions, 152 deletions

diff --git a/cmd/geth/chaincmd.go b/cmd/geth/chaincmd.go
index f9fd8c013..4a9a7b11b 100644
--- a/cmd/geth/chaincmd.go
+++ b/cmd/geth/chaincmd.go
@@ -19,7 +19,6 @@ package main
 import (
 	"encoding/json"
 	"fmt"
-	"math/big"
 	"os"
 	"runtime"
 	"strconv"
@@ -97,13 +96,15 @@ if already existing.`,
 	copydbCommand = cli.Command{
 		Action:    utils.MigrateFlags(copyDb),
 		Name:      "copydb",
-		Usage:     "Copy from one chain DB into another using the downloader",
-		ArgsUsage: "<filename>",
+		Usage:     "Create a local chain from a target chaindata folder",
+		ArgsUsage: "<sourceChaindataDir>",
 		Flags: []cli.Flag{
 			utils.DataDirFlag,
 			utils.CacheFlag,
 			utils.SyncModeFlag,
 			utils.FakePoWFlag,
+			utils.TestnetFlag,
+			utils.RinkebyFlag,
 		},
 		Category: "BLOCKCHAIN COMMANDS",
 		Description: `
@@ -286,172 +287,44 @@ func exportChain(ctx *cli.Context) error {
 	return nil
 }
 
-type localPeer struct {
-	chainDb ethdb.Database
-	hc      *core.HeaderChain
-	dl      *downloader.Downloader
-}
-
-func (lp *localPeer) Head() (common.Hash, *big.Int) {
-	header := lp.hc.CurrentHeader()
-	return header.Hash(), header.Number
-}
-
-func (lp *localPeer) RequestHeadersByHash(hash common.Hash, amount int, skip int, reverse bool) error {
-	var (
-		headers []*types.Header
-		unknown bool
-	)
-
-	for !unknown && len(headers) < amount {
-		origin := lp.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 := lp.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 := lp.hc.GetHeaderByNumber(next); header != nil {
-				if lp.hc.GetBlockHashesFromHash(header.Hash(), uint64(skip+1))[skip] == hash {
-					hash = header.Hash()
-				} else {
-					unknown = true
-				}
-			} else {
-				unknown = true
-			}
-		}
-	}
-
-	lp.dl.DeliverHeaders("local", headers)
-	return nil
-}
-
-func (lp *localPeer) RequestHeadersByNumber(num uint64, amount int, skip int, reverse bool) error {
-	var (
-		headers []*types.Header
-		unknown bool
-	)
-
-	for !unknown && len(headers) < amount {
-		origin := lp.hc.GetHeaderByNumber(num)
-		if origin == nil {
-			break
-		}
-
-		if reverse {
-			if num >= uint64(skip+1) {
-				num -= uint64(skip + 1)
-			} else {
-				unknown = true
-			}
-		} else {
-			num += uint64(skip + 1)
-		}
-		headers = append(headers, origin)
-	}
-
-	lp.dl.DeliverHeaders("local", headers)
-	return nil
-}
-
-func (lp *localPeer) RequestBodies(hashes []common.Hash) error {
-	var (
-		transactions [][]*types.Transaction
-		uncles       [][]*types.Header
-	)
-
-	for _, hash := range hashes {
-		block := core.GetBlock(lp.chainDb, hash, lp.hc.GetBlockNumber(hash))
-		transactions = append(transactions, block.Transactions())
-		uncles = append(uncles, block.Uncles())
-	}
-
-	lp.dl.DeliverBodies("local", transactions, uncles)
-	return nil
-}
-
-func (lp *localPeer) RequestReceipts(hashes []common.Hash) error {
-	var receipts [][]*types.Receipt
-
-	for _, hash := range hashes {
-		receipts = append(receipts, core.GetBlockReceipts(lp.chainDb, hash, lp.hc.GetBlockNumber(hash)))
-	}
-
-	lp.dl.DeliverReceipts("local", receipts)
-	return nil
-}
-
-func (lp *localPeer) RequestNodeData(hashes []common.Hash) error {
-	var data [][]byte
-
-	for _, hash := range hashes {
-		if entry, err := lp.chainDb.Get(hash.Bytes()); err == nil {
-			data = append(data, entry)
-		}
-	}
-
-	lp.dl.DeliverNodeData("local", data)
-	return nil
-}
-
 func copyDb(ctx *cli.Context) error {
+	// Ensure we have a source chain directory to copy
 	if len(ctx.Args()) != 1 {
-		utils.Fatalf("This command requires an argument.")
+		utils.Fatalf("Source chaindata directory path argument missing")
 	}
-
+	// Initialize a new chain for the running node to sync into
 	stack := makeFullNode(ctx)
 	chain, chainDb := utils.MakeChain(ctx, stack)
-	start := time.Now()
 
 	syncmode := *utils.GlobalTextMarshaler(ctx, utils.SyncModeFlag.Name).(*downloader.SyncMode)
-	mux := new(event.TypeMux)
-	dl := downloader.New(syncmode, chainDb, mux, chain, nil, nil)
+	dl := downloader.New(syncmode, chainDb, new(event.TypeMux), chain, nil, nil)
 
-	var err error
-	filename := ctx.Args().First()
-	cache := ctx.GlobalInt(utils.CacheFlag.Name)
-	handles := 256
-	localdb, err := ethdb.NewLDBDatabase(filename, cache, handles)
+	// Create a source peer to satisfy downloader requests from
+	db, err := ethdb.NewLDBDatabase(ctx.Args().First(), ctx.GlobalInt(utils.CacheFlag.Name), 256)
 	if err != nil {
 		return err
 	}
-
-	hc, err := core.NewHeaderChain(localdb, chain.Config(), chain.Engine(), func() bool { return false })
+	hc, err := core.NewHeaderChain(db, chain.Config(), chain.Engine(), func() bool { return false })
 	if err != nil {
 		return err
 	}
-
-	peer := &localPeer{localdb, hc, dl}
-	if err := dl.RegisterPeer("local", 63, peer); err != nil {
+	peer := downloader.NewFakePeer("local", db, hc, dl)
+	if err = dl.RegisterPeer("local", 63, peer); err != nil {
 		return err
 	}
+	// Synchronise with the simulated peer
+	start := time.Now()
 
 	currentHeader := hc.CurrentHeader()
-	if err := dl.Synchronise("local", currentHeader.Hash(), hc.GetTd(currentHeader.Hash(), currentHeader.Number.Uint64()), syncmode); err != nil {
+	if err = dl.Synchronise("local", currentHeader.Hash(), hc.GetTd(currentHeader.Hash(), currentHeader.Number.Uint64()), syncmode); err != nil {
 		return err
 	}
 	for dl.Synchronising() {
 		time.Sleep(10 * time.Millisecond)
 	}
+	fmt.Printf("Database copy done in %v\n", time.Since(start))
 
-	fmt.Printf("Database copy done in %v", time.Since(start))
-
+	// Compact the entire database to remove any sync overhead
 	start = time.Now()
 	fmt.Println("Compacting entire database...")
 	if err = chainDb.(*ethdb.LDBDatabase).LDB().CompactRange(util.Range{}); err != nil {
diff --git a/cmd/utils/flags.go b/cmd/utils/flags.go
index a62b4940b..bfef619f6 100644
--- a/cmd/utils/flags.go
+++ b/cmd/utils/flags.go
@@ -31,6 +31,8 @@ import (
 	"github.com/ethereum/go-ethereum/accounts"
 	"github.com/ethereum/go-ethereum/accounts/keystore"
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/consensus"
+	"github.com/ethereum/go-ethereum/consensus/clique"
 	"github.com/ethereum/go-ethereum/consensus/ethash"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/state"
@@ -1086,17 +1088,22 @@ func MakeChain(ctx *cli.Context, stack *node.Node) (chain *core.BlockChain, chai
 	var err error
 	chainDb = MakeChainDatabase(ctx, stack)
 
-	engine := ethash.NewFaker()
-	if !ctx.GlobalBool(FakePoWFlag.Name) {
-		engine = ethash.New(
-			stack.ResolvePath(eth.DefaultConfig.EthashCacheDir), eth.DefaultConfig.EthashCachesInMem, eth.DefaultConfig.EthashCachesOnDisk,
-			stack.ResolvePath(eth.DefaultConfig.EthashDatasetDir), eth.DefaultConfig.EthashDatasetsInMem, eth.DefaultConfig.EthashDatasetsOnDisk,
-		)
-	}
 	config, _, err := core.SetupGenesisBlock(chainDb, MakeGenesis(ctx))
 	if err != nil {
 		Fatalf("%v", err)
 	}
+	var engine consensus.Engine
+	if config.Clique != nil {
+		engine = clique.New(config.Clique, chainDb)
+	} else {
+		engine = ethash.NewFaker()
+		if !ctx.GlobalBool(FakePoWFlag.Name) {
+			engine = ethash.New(
+				stack.ResolvePath(eth.DefaultConfig.EthashCacheDir), eth.DefaultConfig.EthashCachesInMem, eth.DefaultConfig.EthashCachesOnDisk,
+				stack.ResolvePath(eth.DefaultConfig.EthashDatasetDir), eth.DefaultConfig.EthashDatasetsInMem, eth.DefaultConfig.EthashDatasetsOnDisk,
+			)
+		}
+	}
 	vmcfg := vm.Config{EnablePreimageRecording: ctx.GlobalBool(VMEnableDebugFlag.Name)}
 	chain, err = core.NewBlockChain(chainDb, config, engine, vmcfg)
 	if err != nil {
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
+}