core, dex/downloader: polish headers verification and blocks insertion logic (#168)

Refactor GenerateDexonChain function, move governance tx logic to
the user of GenerateDexonChain (testchain_test.go) and move fake node set
code to FakeDexcon.

1 files changed, 312 insertions, 0 deletions

diff --git a/core/dexon_chain_makers.go b/core/dexon_chain_makers.go
new file mode 100644
index 000000000..128cc454b
--- /dev/null
+++ b/core/dexon_chain_makers.go
@@ -0,0 +1,312 @@
+// Copyright 2015 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 core
+
+import (
+	"fmt"
+	"math/big"
+	"math/rand"
+	"time"
+
+	coreTypes "github.com/dexon-foundation/dexon-consensus/core/types"
+
+	"github.com/dexon-foundation/dexon/common"
+	"github.com/dexon-foundation/dexon/consensus"
+	"github.com/dexon-foundation/dexon/core/state"
+	"github.com/dexon-foundation/dexon/core/types"
+	"github.com/dexon-foundation/dexon/core/vm"
+	"github.com/dexon-foundation/dexon/ethdb"
+	"github.com/dexon-foundation/dexon/params"
+	"github.com/dexon-foundation/dexon/rlp"
+)
+
+func init() {
+	rand.Seed(time.Now().UTC().UnixNano())
+}
+
+// DexonBlockGen creates blocks for testing.
+// See GenerateChain for a detailed explanation.
+type DexonBlockGen struct {
+	i       int
+	parent  *types.Block
+	chain   []*types.Block
+	header  *types.Header
+	statedb *state.StateDB
+
+	dirtyNonce map[common.Address]uint64
+
+	position coreTypes.Position
+
+	gasPool  *GasPool
+	txs      []*types.Transaction
+	receipts []*types.Receipt
+
+	config *params.ChainConfig
+	engine consensus.Engine
+}
+
+// SetCoinbase sets the coinbase of the generated block.
+// It can be called at most once.
+func (b *DexonBlockGen) SetCoinbase(addr common.Address) {
+	if b.gasPool != nil {
+		if len(b.txs) > 0 {
+			panic("coinbase must be set before adding transactions")
+		}
+		panic("coinbase can only be set once")
+	}
+	b.header.Coinbase = addr
+	b.gasPool = new(GasPool).AddGas(b.header.GasLimit)
+}
+
+// SetExtra sets the extra data field of the generated block.
+func (b *DexonBlockGen) SetExtra(data []byte) {
+	b.header.Extra = data
+}
+
+// SetNonce sets the nonce field of the generated block.
+func (b *DexonBlockGen) SetNonce(nonce types.BlockNonce) {
+	b.header.Nonce = nonce
+}
+
+func (b *DexonBlockGen) SetPosition(position coreTypes.Position) {
+	b.position = position
+}
+
+// AddTx adds a transaction to the generated block. If no coinbase has
+// been set, the block's coinbase is set to the zero address.
+//
+// AddTx panics if the transaction cannot be executed. In addition to
+// the protocol-imposed limitations (gas limit, etc.), there are some
+// further limitations on the content of transactions that can be
+// added. If contract code relies on the BLOCKHASH instruction,
+// the block in chain will be returned.
+func (b *DexonBlockGen) AddTx(tx *types.Transaction) {
+	// TODO: check nonce and maintain nonce.
+	b.txs = append(b.txs, tx)
+}
+
+func (b *DexonBlockGen) PreparePayload() []byte {
+	return nil
+}
+
+func (b *DexonBlockGen) ProcessTransactions(c ChainContext) {
+	if b.gasPool == nil {
+		b.SetCoinbase(common.Address{})
+	}
+	for _, tx := range b.txs {
+		b.statedb.Prepare(tx.Hash(), common.Hash{}, len(b.txs))
+		// TODO: fix the chain context parameter
+		receipt, _, err := ApplyTransaction(b.config, c, &b.header.Coinbase, b.gasPool, b.statedb, b.header, tx, &b.header.GasUsed, vm.Config{})
+		if err != nil {
+			panic(err)
+		}
+		b.receipts = append(b.receipts, receipt)
+	}
+}
+
+// Number returns the block number of the block being generated.
+func (b *DexonBlockGen) Number() *big.Int {
+	return new(big.Int).Set(b.header.Number)
+}
+
+// AddUncheckedReceipt forcefully adds a receipts to the block without a
+// backing transaction.
+//
+// AddUncheckedReceipt will cause consensus failures when used during real
+// chain processing. This is best used in conjunction with raw block insertion.
+func (b *DexonBlockGen) AddUncheckedReceipt(receipt *types.Receipt) {
+	b.receipts = append(b.receipts, receipt)
+}
+
+// TxNonce returns the next valid transaction nonce for the
+// account at addr. It panics if the account does not exist.
+func (b *DexonBlockGen) TxNonce(addr common.Address) uint64 {
+	if !b.statedb.Exist(addr) {
+		panic("account does not exist")
+	}
+	if nonce, exists := b.dirtyNonce[addr]; exists {
+		return nonce
+	}
+	return b.statedb.GetNonce(addr)
+}
+
+// PrevBlock returns a previously generated block by number. It panics if
+// num is greater or equal to the number of the block being generated.
+// For index -1, PrevBlock returns the parent block given to GenerateChain.
+func (b *DexonBlockGen) PrevBlock(index int) *types.Block {
+	if index >= b.i {
+		panic(fmt.Errorf("block index %d out of range (%d,%d)", index, -1, b.i))
+	}
+	if index == -1 {
+		return b.parent
+	}
+	return b.chain[index]
+}
+
+func GenerateDexonChain(config *params.ChainConfig, parent *types.Block, engine consensus.Engine, db ethdb.Database, n int, gen func(int, *DexonBlockGen)) ([]*types.Block, []types.Receipts) {
+	if config == nil {
+		config = params.TestChainConfig
+	}
+	if engine == nil {
+		panic("engine is nil")
+	}
+	blocks, receipts := make(types.Blocks, n), make([]types.Receipts, n)
+	chain := &fakeDexonChain{
+		config:          config,
+		engine:          engine,
+		genesis:         parent,
+		db:              db,
+		headersByNumber: make(map[uint64]*types.Header),
+		roundHeight:     make(map[uint64]uint64),
+	}
+	genblock := func(i int, parent *types.Block, statedb *state.StateDB) (*types.Block, types.Receipts) {
+		b := &DexonBlockGen{i: i, chain: blocks, parent: parent, statedb: statedb, config: config, engine: engine}
+		b.header = makeDexonHeader(chain, parent, statedb, b.engine)
+
+		// Execute any user modifications to the block
+		if gen != nil {
+			gen(i, b)
+		}
+
+		b.header.DexconMeta = makeDexconMeta(b, parent)
+
+		// sign tsig to create dexcon, prepare witness
+		b.engine.Prepare(chain, b.header)
+
+		// Run EVM and finalize the block.
+		b.ProcessTransactions(chain)
+
+		// Finalize and seal the block
+		block, _ := b.engine.Finalize(chain, b.header, statedb, b.txs, nil, b.receipts)
+
+		// Write state changes to db
+		root, err := statedb.Commit(config.IsEIP158(b.header.Number))
+		if err != nil {
+			panic(fmt.Sprintf("state write error: %v", err))
+		}
+		if err := statedb.Database().TrieDB().Commit(root, false); err != nil {
+			panic(fmt.Sprintf("trie write error: %v", err))
+		}
+		return block, b.receipts
+	}
+	for i := 0; i < n; i++ {
+		statedb, err := state.New(parent.Root(), state.NewDatabase(db))
+		if err != nil {
+			panic(err)
+		}
+		block, receipt := genblock(i, parent, statedb)
+		blocks[i] = block
+		receipts[i] = receipt
+		parent = block
+		chain.InsertBlock(block)
+	}
+	return blocks, receipts
+}
+
+func makeDexonHeader(chain consensus.ChainReader, parent *types.Block, state *state.StateDB, engine consensus.Engine) *types.Header {
+	var time uint64
+	if parent.Time() == 0 {
+		time = 10
+	} else {
+		time = parent.Time() + 10 // block time is fixed at 10 seconds
+	}
+
+	return &types.Header{
+		Root:       state.IntermediateRoot(chain.Config().IsEIP158(parent.Number())),
+		ParentHash: parent.Hash(),
+		Coinbase:   parent.Coinbase(),
+		Difficulty: new(big.Int).Add(parent.Difficulty(), common.Big1),
+		GasLimit:   chain.Config().Dexcon.BlockGasLimit,
+		Number:     new(big.Int).Add(parent.Number(), common.Big1),
+		Time:       time,
+	}
+}
+
+// Setup DexconMeata skeleton
+func makeDexconMeta(b *DexonBlockGen, parent *types.Block) []byte {
+	// Setup witness
+	h := parent.Number().Int64() - rand.Int63n(6)
+	if h < 0 {
+		h = 0
+	}
+	witnessedBlock := b.chain[h]
+	if witnessedBlock == nil {
+		witnessedBlock = parent
+	}
+	witnessedBlockHash := witnessedBlock.Hash()
+	data, err := rlp.EncodeToBytes(&witnessedBlockHash)
+	if err != nil {
+		panic(err)
+	}
+
+	block := coreTypes.Block{
+		Position: b.position,
+		Witness: coreTypes.Witness{
+			Height: witnessedBlock.NumberU64(),
+			Data:   data,
+		},
+	}
+
+	dexconMeta, err := rlp.EncodeToBytes(&block)
+	if err != nil {
+		panic(err)
+	}
+	return dexconMeta
+}
+
+type fakeDexonChain struct {
+	config          *params.ChainConfig
+	engine          consensus.Engine
+	db              ethdb.Database
+	genesis         *types.Block
+	headersByNumber map[uint64]*types.Header
+	roundHeight     map[uint64]uint64
+}
+
+func (f *fakeDexonChain) InsertBlock(block *types.Block) {
+	f.headersByNumber[block.NumberU64()] = block.Header()
+	if _, exists := f.roundHeight[block.Round()]; !exists {
+		f.roundHeight[block.Round()] = block.NumberU64()
+	}
+}
+
+// Config returns the chain configuration.
+func (f *fakeDexonChain) Config() *params.ChainConfig                             { return f.config }
+func (f *fakeDexonChain) Engine() consensus.Engine                                { return f.engine }
+func (f *fakeDexonChain) CurrentHeader() *types.Header                            { return nil }
+func (f *fakeDexonChain) GetHeaderByHash(hash common.Hash) *types.Header          { return nil }
+func (f *fakeDexonChain) GetHeader(hash common.Hash, number uint64) *types.Header { return nil }
+func (f *fakeDexonChain) GetBlock(hash common.Hash, number uint64) *types.Block   { return nil }
+
+func (f *fakeDexonChain) GetHeaderByNumber(number uint64) *types.Header {
+	if number == 0 {
+		return f.genesis.Header()
+	}
+	return f.headersByNumber[number]
+}
+
+func (f *fakeDexonChain) StateAt(hash common.Hash) (*state.StateDB, error) {
+	return state.New(hash, state.NewDatabase(f.db))
+}
+
+func (f *fakeDexonChain) GetRoundHeight(round uint64) (uint64, bool) {
+	if round == 0 {
+		return 0, true
+	}
+	height, ok := f.roundHeight[round]
+	return height, ok
+}