consensus: dexcon: fetch config from state

7 files changed, 51 insertions, 41 deletions

diff --git a/consensus/dexcon/dexcon.go b/consensus/dexcon/dexcon.go
index 46090b757..e636108f8 100644
--- a/consensus/dexcon/dexcon.go
+++ b/consensus/dexcon/dexcon.go
@@ -27,21 +27,26 @@ import (
 	"github.com/dexon-foundation/dexon/rpc"
 )
 
-// Config is the configuration for DEXON consensus.
-type Config struct {
+type ConfigurationFetcher interface {
+	DexconConfiguration(round uint64) *params.DexconConfig
 }
 
 // Dexcon is a delegated proof-of-stake consensus engine.
 type Dexcon struct {
-	config *params.DexconConfig
+	configFetcher ConfigurationFetcher
 }
 
 // New creates a Clique proof-of-authority consensus engine with the initial
 // signers set to the ones provided by the user.
-func New(config *params.DexconConfig) *Dexcon {
-	return &Dexcon{
-		config: config,
-	}
+func New() *Dexcon {
+	return &Dexcon{}
+}
+
+// SetConfigFetcher sets the config fetcher for Dexcon. The reason this is not
+// passed in the New() method is to bypass cycle dependencies when initializing
+// dex backend.
+func (d *Dexcon) SetConfigFetcher(fetcher ConfigurationFetcher) {
+	d.configFetcher = fetcher
 }
 
 // Author implements consensus.Engine, returning the Ethereum address recovered
@@ -105,11 +110,10 @@ func (d *Dexcon) Prepare(chain consensus.ChainReader, header *types.Header) erro
 // Finalize implements consensus.Engine, ensuring no uncles are set, nor block
 // rewards given, and returns the final block.
 func (d *Dexcon) Finalize(chain consensus.ChainReader, header *types.Header, state *state.StateDB, txs []*types.Transaction, uncles []*types.Header, receipts []*types.Receipt) (*types.Block, error) {
-	// TODO(Bojie): remove it and get value from config
-	reward := new(big.Int).Div(d.config.BlockReward, new(big.Int).SetUint64(uint64(d.config.NumChains)))
+	config := d.configFetcher.DexconConfiguration(header.Position.Round)
+	reward := new(big.Int).Div(config.BlockReward, big.NewInt(int64(config.NumChains)))
 	state.AddBalance(header.Coinbase, reward)
 	header.Root = state.IntermediateRoot(true)
-
 	return types.NewBlock(header, txs, uncles, receipts), nil
 }
 
diff --git a/core/types/block.go b/core/types/block.go
index 2d9ba45e4..376c94f3e 100644
--- a/core/types/block.go
+++ b/core/types/block.go
@@ -26,6 +26,8 @@ import (
 	"time"
 	"unsafe"
 
+	coreTypes "github.com/dexon-foundation/dexon-consensus-core/core/types"
+
 	"github.com/dexon-foundation/dexon/common"
 	"github.com/dexon-foundation/dexon/common/hexutil"
 	"github.com/dexon-foundation/dexon/rlp"
@@ -68,25 +70,26 @@ func (n *BlockNonce) UnmarshalText(input []byte) error {
 
 // Header represents a block header in the Ethereum blockchain.
 type Header struct {
-	ParentHash         common.Hash    `json:"parentHash"       gencodec:"required"`
-	UncleHash          common.Hash    `json:"sha3Uncles"       gencodec:"required"`
-	Coinbase           common.Address `json:"miner"            gencodec:"required"`
-	Root               common.Hash    `json:"stateRoot"        gencodec:"required"`
-	TxHash             common.Hash    `json:"transactionsRoot" gencodec:"required"`
-	ReceiptHash        common.Hash    `json:"receiptsRoot"     gencodec:"required"`
-	Bloom              Bloom          `json:"logsBloom"        gencodec:"required"`
-	Difficulty         *big.Int       `json:"difficulty"       gencodec:"required"`
-	Number             *big.Int       `json:"number"           gencodec:"required"`
-	GasLimit           uint64         `json:"gasLimit"         gencodec:"required"`
-	GasUsed            uint64         `json:"gasUsed"          gencodec:"required"`
-	Time               *big.Int       `json:"timestamp"        gencodec:"required"`
-	Extra              []byte         `json:"extraData"        gencodec:"required"`
-	MixDigest          common.Hash    `json:"mixHash"`
-	Nonce              BlockNonce     `json:"nonce"`
-	Randomness         []byte         `json:"randomness"         gencodec:"required"`
-	WitnessHeight      uint64         `json:"witnessHeight"      gencodec:"required"`
-	WitnessRoot        common.Hash    `json:"WitnessRoot"        gencodec:"required"`
-	WitnessReceiptHash common.Hash    `json:"WitnessReceiptHash" gencodec:"required"`
+	ParentHash         common.Hash        `json:"parentHash"       gencodec:"required"`
+	UncleHash          common.Hash        `json:"sha3Uncles"       gencodec:"required"`
+	Coinbase           common.Address     `json:"miner"            gencodec:"required"`
+	Root               common.Hash        `json:"stateRoot"        gencodec:"required"`
+	TxHash             common.Hash        `json:"transactionsRoot" gencodec:"required"`
+	ReceiptHash        common.Hash        `json:"receiptsRoot"     gencodec:"required"`
+	Bloom              Bloom              `json:"logsBloom"        gencodec:"required"`
+	Difficulty         *big.Int           `json:"difficulty"       gencodec:"required"`
+	Number             *big.Int           `json:"number"           gencodec:"required"`
+	GasLimit           uint64             `json:"gasLimit"         gencodec:"required"`
+	GasUsed            uint64             `json:"gasUsed"          gencodec:"required"`
+	Time               *big.Int           `json:"timestamp"        gencodec:"required"`
+	Extra              []byte             `json:"extraData"        gencodec:"required"`
+	MixDigest          common.Hash        `json:"mixHash"`
+	Nonce              BlockNonce         `json:"nonce"`
+	Randomness         []byte             `json:"randomness"         gencodec:"required"`
+	Position           coreTypes.Position `json:"position"           gencodec:"required"`
+	WitnessHeight      uint64             `json:"witnessHeight"      gencodec:"required"`
+	WitnessRoot        common.Hash        `json:"WitnessRoot"        gencodec:"required"`
+	WitnessReceiptHash common.Hash        `json:"WitnessReceiptHash" gencodec:"required"`
 }
 
 // field type overrides for gencodec
diff --git a/dex/app.go b/dex/app.go
index 317711e94..ab23301d5 100644
--- a/dex/app.go
+++ b/dex/app.go
@@ -223,6 +223,7 @@ func (d *DexconApp) BlockDelivered(blockHash coreCommon.Hash, result coreTypes.F
 		Number:             new(big.Int).SetUint64(result.Height),
 		Time:               big.NewInt(result.Timestamp.Unix()),
 		Coinbase:           common.BytesToAddress(block.ProposerID.Bytes()),
+		Position:           block.Position,
 		WitnessHeight:      block.Witness.Height,
 		WitnessRoot:        witnessData.Root,
 		WitnessReceiptHash: witnessData.ReceiptHash,
diff --git a/dex/backend.go b/dex/backend.go
index 7a23ba80b..2f6d8a8e5 100644
--- a/dex/backend.go
+++ b/dex/backend.go
@@ -110,6 +110,8 @@ func New(ctx *node.ServiceContext, config *Config) (*Dexon, error) {
 		}
 		rawdb.WriteDatabaseVersion(chainDb, core.BlockChainVersion)
 	}
+	engine := dexcon.New()
+
 	dex := &Dexon{
 		config:         config,
 		chainDb:        chainDb,
@@ -121,7 +123,7 @@ func New(ctx *node.ServiceContext, config *Config) (*Dexon, error) {
 		bloomRequests:  make(chan chan *bloombits.Retrieval),
 		bloomIndexer:   NewBloomIndexer(chainDb, params.BloomBitsBlocks, params.BloomConfirms),
 		blockdb:        db,
-		engine:         dexcon.New(chainConfig.Dexcon),
+		engine:         engine,
 	}
 
 	var (
@@ -154,9 +156,13 @@ func New(ctx *node.ServiceContext, config *Config) (*Dexon, error) {
 	}
 	dex.APIBackend.gpo = gasprice.NewOracle(dex.APIBackend, gpoParams)
 
+	// Dexcon related objects.
 	dex.governance = NewDexconGovernance(dex.APIBackend, dex.chainConfig, config.PrivateKey)
 	dex.app = NewDexconApp(dex.txPool, dex.blockchain, dex.governance, chainDb, config, vmConfig)
 
+	// Set config fetcher so engine can fetch current system configuration from state.
+	engine.SetConfigFetcher(dex.governance)
+
 	pm, err := NewProtocolManager(dex.chainConfig, config.SyncMode,
 		config.NetworkId, dex.eventMux, dex.txPool, dex.engine, dex.blockchain,
 		chainDb, dex.governance)
diff --git a/dex/config.go b/dex/config.go
index 507ccf5e3..4d76ec8fe 100644
--- a/dex/config.go
+++ b/dex/config.go
@@ -25,7 +25,6 @@ import (
 	"runtime"
 	"time"
 
-	"github.com/dexon-foundation/dexon/consensus/dexcon"
 	"github.com/dexon-foundation/dexon/core"
 	"github.com/dexon-foundation/dexon/dex/gasprice"
 	"github.com/dexon-foundation/dexon/eth/downloader"
@@ -35,7 +34,6 @@ import (
 // DefaultConfig contains default settings for use on the Ethereum main net.
 var DefaultConfig = Config{
 	SyncMode:       downloader.FastSync,
-	Dexcon:         dexcon.Config{},
 	NetworkId:      1,
 	LightPeers:     100,
 	DatabaseCache:  768,
@@ -102,9 +100,6 @@ type Config struct {
 	GasCeil           uint64
 	GasLimitTolerance uint64
 
-	// Dexcon options
-	Dexcon dexcon.Config
-
 	// Transaction pool options
 	TxPool core.TxPoolConfig
 
diff --git a/dex/governance.go b/dex/governance.go
index 4ec69c2d6..50ab7ee14 100644
--- a/dex/governance.go
+++ b/dex/governance.go
@@ -79,7 +79,13 @@ func (d *DexconGovernance) getGovStateAtRound(round uint64) *vm.GovernanceStateH
 	return &vm.GovernanceStateHelper{state}
 }
 
-// Configuration return the total ordering K constant.
+// DexconConfiguration return raw config in state.
+func (d *DexconGovernance) DexconConfiguration(round uint64) *params.DexconConfig {
+	s := d.getGovStateAtRound(round)
+	return s.Configuration()
+}
+
+// Configuration returns the system configuration for consensus core to use.
 func (d *DexconGovernance) Configuration(round uint64) *coreTypes.Config {
 	s := d.getGovStateAtRound(round)
 	c := s.Configuration()
diff --git a/eth/backend.go b/eth/backend.go
index 87eb8a2ae..04e4569f2 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -30,7 +30,6 @@ import (
 	"github.com/dexon-foundation/dexon/common/hexutil"
 	"github.com/dexon-foundation/dexon/consensus"
 	"github.com/dexon-foundation/dexon/consensus/clique"
-	"github.com/dexon-foundation/dexon/consensus/dexcon"
 	"github.com/dexon-foundation/dexon/consensus/ethash"
 	"github.com/dexon-foundation/dexon/core"
 	"github.com/dexon-foundation/dexon/core/bloombits"
@@ -225,10 +224,6 @@ func CreateDB(ctx *node.ServiceContext, config *Config, name string) (ethdb.Data
 // CreateConsensusEngine creates the required type of consensus engine instance for an Ethereum service
 func CreateConsensusEngine(ctx *node.ServiceContext, chainConfig *params.ChainConfig, config *ethash.Config, notify []string, noverify bool, db ethdb.Database) consensus.Engine {
 	// If proof-of-authority is requested, set it up
-	if chainConfig.Dexcon != nil {
-		return dexcon.New(chainConfig.Dexcon)
-	}
-	// If proof-of-authority is requested, set it up
 	if chainConfig.Clique != nil {
 		return clique.New(chainConfig.Clique, db)
 	}