dex: implement dexon application interface

1 files changed, 210 insertions, 13 deletions

diff --git a/dex/app.go b/dex/app.go
index a8b04577d..80384ddc9 100644
--- a/dex/app.go
+++ b/dex/app.go
@@ -18,37 +18,234 @@
 package dex
 
 import (
-	"github.com/dexon-foundation/dexon-consensus-core/core/types"
+	"bytes"
+	"math/big"
+	"sync"
+	"time"
 
+	coreTypes "github.com/dexon-foundation/dexon-consensus-core/core/types"
+
+	"github.com/dexon-foundation/dexon/common"
 	"github.com/dexon-foundation/dexon/core"
+	"github.com/dexon-foundation/dexon/core/rawdb"
+	"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/rlp"
 )
 
 // DexconApp implementes the DEXON consensus core application interface.
 type DexconApp struct {
-	txPool *core.TxPool
+	txPool     *core.TxPool
+	blockchain *core.BlockChain
+	gov        *DexconGovernance
+	chainDB    ethdb.Database
+	config     *Config
+	vmConfig   vm.Config
+
+	notifyChan map[uint64]*notify
+	mutex      *sync.Mutex
+}
+
+type notify struct {
+	results []chan bool
 }
 
-func NewDexconApp(txPool *core.TxPool) *DexconApp {
+func NewDexconApp(txPool *core.TxPool, blockchain *core.BlockChain, gov *DexconGovernance, chainDB ethdb.Database, config *Config, vmConfig vm.Config) *DexconApp {
 	return &DexconApp{
-		txPool: txPool,
+		txPool:     txPool,
+		blockchain: blockchain,
+		gov:        gov,
+		chainDB:    chainDB,
+		config:     config,
+		vmConfig:   vmConfig,
+		notifyChan: make(map[uint64]*notify),
+		mutex:      &sync.Mutex{},
 	}
 }
 
-// PreparePayload is called when consensus core is preparing a block.
-func (d *DexconApp) PreparePayload(position types.Position) []byte {
-	return nil
+func (d *DexconApp) addNotify(height uint64) <-chan bool {
+	d.mutex.Lock()
+	defer d.mutex.Unlock()
+	result := make(chan bool)
+	if n, exist := d.notifyChan[height]; exist {
+		n.results = append(n.results, result)
+	} else {
+		d.notifyChan[height] = &notify{}
+		d.notifyChan[height].results = append(d.notifyChan[height].results, result)
+	}
+	return result
 }
 
-// PrepareWitness will return the witness data no lower than consensusHeight.
-func (d *DexconApp) PrepareWitness(consensusHeight uint64) types.Witness {
-	return types.Witness{}
+func (d *DexconApp) notify(height uint64) {
+	d.mutex.Lock()
+	defer d.mutex.Unlock()
+	for h, n := range d.notifyChan {
+		if height >= h {
+			for _, ch := range n.results {
+				ch <- true
+			}
+			delete(d.notifyChan, h)
+		}
+	}
 }
 
-// VerifyPayload verifies if the payloads are valid.
-func (d *DexconApp) VerifyBlock(block *types.Block) bool {
+// PreparePayload is called when consensus core is preparing payload for block.
+func (d *DexconApp) PreparePayload(position coreTypes.Position) (payload []byte) {
+	txsMap, err := d.txPool.Pending()
+	if err != nil {
+		return
+	}
+
+	currentBlock := d.blockchain.CurrentBlock()
+	gasLimit := core.CalcGasLimit(currentBlock, d.config.GasFloor, d.config.GasCeil)
+	gp := new(core.GasPool).AddGas(gasLimit)
+
+	stateDB, err := state.New(currentBlock.Root(), state.NewDatabase(d.chainDB))
+	if err != nil {
+		return
+	}
+
+	chainID := new(big.Int).SetUint64(uint64(position.ChainID))
+	chainSize := new(big.Int).SetUint64(uint64(d.gov.Configuration(position.Round).NumChains))
+	var allTxs types.Transactions
+	var gasUsed uint64
+	for addr, txs := range txsMap {
+		addrModChainSize := new(big.Int)
+		if addrModChainSize.Mod(addr.Big(), chainSize).Cmp(chainID) != 0 {
+			continue
+		}
+
+		for _, tx := range txs {
+			core.ApplyTransaction(d.blockchain.Config(), d.blockchain, nil, gp, stateDB, currentBlock.Header(), tx, &gasUsed, d.vmConfig)
+			if gasUsed > gasLimit {
+				break
+			}
+			allTxs = append(allTxs, tx)
+		}
+	}
+	payload, err = rlp.EncodeToBytes(&allTxs)
+	if err != nil {
+		// do something
+		return
+	}
+
+	return
+}
+
+type WitnessData struct {
+	Root        common.Hash
+	TxHash      common.Hash
+	ReceiptHash common.Hash
+}
+
+func (d *DexconApp) PrepareWitness(consensusHeight uint64) (witness coreTypes.Witness) {
+	var currentBlock *types.Block
+	currentBlock = d.blockchain.CurrentBlock()
+	if currentBlock.NumberU64() < consensusHeight {
+		// wait notification
+		if <-d.addNotify(consensusHeight) {
+			currentBlock = d.blockchain.CurrentBlock()
+		} else {
+			// do something if notify fail
+		}
+	}
+
+	witnessData, err := rlp.EncodeToBytes(&WitnessData{
+		Root:        currentBlock.Root(),
+		TxHash:      currentBlock.TxHash(),
+		ReceiptHash: currentBlock.ReceiptHash(),
+	})
+	if err != nil {
+		return
+	}
+
+	return coreTypes.Witness{
+		Timestamp: time.Unix(currentBlock.Time().Int64(), 0),
+		Height:    currentBlock.NumberU64(),
+		Data:      witnessData,
+	}
+}
+
+// VerifyBlock verifies if the payloads are valid.
+func (d *DexconApp) VerifyBlock(block *coreTypes.Block) bool {
+	// decode payload to transactions
+	var transactions types.Transactions
+	err := rlp.Decode(bytes.NewReader(block.Payload), &transactions)
+	if err != nil {
+		return false
+	}
+
+	// verify transactions
+	for _, transaction := range transactions {
+		tx, _, _, _ := rawdb.ReadTransaction(d.chainDB, transaction.Hash())
+		if tx == nil || d.txPool.ValidateTx(transaction, false) != nil {
+			return false
+		}
+	}
+
+	currentBlock := d.blockchain.CurrentBlock()
+	gasLimit := core.CalcGasLimit(currentBlock, d.config.GasFloor, d.config.GasCeil)
+	gp := new(core.GasPool).AddGas(gasLimit)
+
+	stateDB, err := state.New(currentBlock.Root(), state.NewDatabase(d.chainDB))
+	if err != nil {
+		return false
+	}
+
+	var gasUsed uint64
+	for _, tx := range transactions {
+		core.ApplyTransaction(d.blockchain.Config(), d.blockchain, nil, gp, stateDB, currentBlock.Header(), tx, &gasUsed, d.vmConfig)
+	}
+
+	if gasUsed > gasLimit+d.config.GasLimitTolerance {
+		return false
+	}
+
+	witnessData := WitnessData{}
+	err = rlp.Decode(bytes.NewReader(block.Witness.Data), &witnessData)
+	if err != nil {
+		return false
+	}
+
+	witnessBlock := d.blockchain.GetBlockByNumber(block.Witness.Height)
+	if witnessBlock == nil {
+		return false
+	} else if witnessBlock.Root() != witnessData.Root {
+		// invalid state root of witness data
+		return false
+	} else if witnessBlock.ReceiptHash() != witnessData.ReceiptHash {
+		// invalid receipt root of witness data
+		return false
+	} else if witnessBlock.TxHash() != witnessData.ReceiptHash {
+		// invalid tx root of witness data
+		return false
+	}
+
 	return true
 }
 
 // BlockDelivered is called when a block is add to the compaction chain.
-func (d *DexconApp) BlockDelivered(block types.Block) {
+func (d *DexconApp) BlockDelivered(block coreTypes.Block) {
+	var transactions types.Transactions
+	err := rlp.Decode(bytes.NewReader(block.Payload), &transactions)
+	if err != nil {
+		return
+	}
+
+	_, err = d.blockchain.InsertChain(
+		[]*types.Block{types.NewBlock(&types.Header{
+			ParentHash: common.Hash(block.ParentHash),
+			Number:     new(big.Int).SetUint64(block.ConsensusHeight),
+			Time:       new(big.Int).SetInt64(block.ConsensusTimestamp.Unix()),
+			TxHash:     types.DeriveSha(transactions),
+			Coinbase:   common.BytesToAddress(block.ProposerID.Hash[:]),
+		}, transactions, nil, nil)})
+	if err != nil {
+		// do something
+		return
+	}
+
+	d.notify(block.ConsensusHeight)
 }