dex: add api_backend.go and it's dependencies

4 files changed, 557 insertions, 2 deletions

diff --git a/dex/api_backend.go b/dex/api_backend.go
new file mode 100644
index 000000000..8a147aab2
--- /dev/null
+++ b/dex/api_backend.go
@@ -0,0 +1,217 @@
+// 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 dex
+
+import (
+	"context"
+	"math/big"
+
+	"github.com/dexon-foundation/dexon/accounts"
+	"github.com/dexon-foundation/dexon/common"
+	"github.com/dexon-foundation/dexon/common/math"
+	"github.com/dexon-foundation/dexon/core"
+	"github.com/dexon-foundation/dexon/core/bloombits"
+	"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/eth/gasprice"
+
+	"github.com/dexon-foundation/dexon/ethdb"
+	"github.com/dexon-foundation/dexon/event"
+	"github.com/dexon-foundation/dexon/params"
+	"github.com/dexon-foundation/dexon/rpc"
+)
+
+// DexAPIBackend implements ethapi.Backend for full nodes
+type DexAPIBackend struct {
+	dex *Dexon
+	gpo *gasprice.Oracle
+}
+
+// ChainConfig returns the active chain configuration.
+func (b *DexAPIBackend) ChainConfig() *params.ChainConfig {
+	return b.dex.chainConfig
+}
+
+func (b *DexAPIBackend) CurrentBlock() *types.Block {
+	return b.dex.blockchain.CurrentBlock()
+}
+
+func (b *DexAPIBackend) SetHead(number uint64) {
+	b.dex.protocolManager.downloader.Cancel()
+	b.dex.blockchain.SetHead(number)
+}
+
+func (b *DexAPIBackend) HeaderByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*types.Header, error) {
+	// Otherwise resolve and return the block
+	if blockNr == rpc.LatestBlockNumber {
+		return b.dex.blockchain.CurrentBlock().Header(), nil
+	}
+	return b.dex.blockchain.GetHeaderByNumber(uint64(blockNr)), nil
+}
+
+func (b *DexAPIBackend) HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error) {
+	return b.dex.blockchain.GetHeaderByHash(hash), nil
+}
+
+func (b *DexAPIBackend) BlockByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*types.Block, error) {
+	// Otherwise resolve and return the block
+	if blockNr == rpc.LatestBlockNumber {
+		return b.dex.blockchain.CurrentBlock(), nil
+	}
+	return b.dex.blockchain.GetBlockByNumber(uint64(blockNr)), nil
+}
+
+func (b *DexAPIBackend) StateAndHeaderByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*state.StateDB, *types.Header, error) {
+	header, err := b.HeaderByNumber(ctx, blockNr)
+	if header == nil || err != nil {
+		return nil, nil, err
+	}
+	stateDb, err := b.dex.BlockChain().StateAt(header.Root)
+	return stateDb, header, err
+}
+
+func (b *DexAPIBackend) GetBlock(ctx context.Context, hash common.Hash) (*types.Block, error) {
+	return b.dex.blockchain.GetBlockByHash(hash), nil
+}
+
+func (b *DexAPIBackend) GetReceipts(ctx context.Context, hash common.Hash) (types.Receipts, error) {
+	if number := rawdb.ReadHeaderNumber(b.dex.chainDb, hash); number != nil {
+		return rawdb.ReadReceipts(b.dex.chainDb, hash, *number), nil
+	}
+	return nil, nil
+}
+
+func (b *DexAPIBackend) GetLogs(ctx context.Context, hash common.Hash) ([][]*types.Log, error) {
+	number := rawdb.ReadHeaderNumber(b.dex.chainDb, hash)
+	if number == nil {
+		return nil, nil
+	}
+	receipts := rawdb.ReadReceipts(b.dex.chainDb, hash, *number)
+	if receipts == nil {
+		return nil, nil
+	}
+	logs := make([][]*types.Log, len(receipts))
+	for i, receipt := range receipts {
+		logs[i] = receipt.Logs
+	}
+	return logs, nil
+}
+
+func (b *DexAPIBackend) GetTd(blockHash common.Hash) *big.Int {
+	return b.dex.blockchain.GetTdByHash(blockHash)
+}
+
+func (b *DexAPIBackend) GetEVM(ctx context.Context, msg core.Message, state *state.StateDB, header *types.Header) (*vm.EVM, func() error, error) {
+	state.SetBalance(msg.From(), math.MaxBig256)
+	vmError := func() error { return nil }
+
+	context := core.NewEVMContext(msg, header, b.dex.BlockChain(), nil)
+	return vm.NewEVM(context, state, b.dex.chainConfig, *b.dex.blockchain.GetVMConfig()), vmError, nil
+}
+
+func (b *DexAPIBackend) SubscribeRemovedLogsEvent(ch chan<- core.RemovedLogsEvent) event.Subscription {
+	return b.dex.BlockChain().SubscribeRemovedLogsEvent(ch)
+}
+
+func (b *DexAPIBackend) SubscribeChainEvent(ch chan<- core.ChainEvent) event.Subscription {
+	return b.dex.BlockChain().SubscribeChainEvent(ch)
+}
+
+func (b *DexAPIBackend) SubscribeChainHeadEvent(ch chan<- core.ChainHeadEvent) event.Subscription {
+	return b.dex.BlockChain().SubscribeChainHeadEvent(ch)
+}
+
+func (b *DexAPIBackend) SubscribeChainSideEvent(ch chan<- core.ChainSideEvent) event.Subscription {
+	return b.dex.BlockChain().SubscribeChainSideEvent(ch)
+}
+
+func (b *DexAPIBackend) SubscribeLogsEvent(ch chan<- []*types.Log) event.Subscription {
+	return b.dex.BlockChain().SubscribeLogsEvent(ch)
+}
+
+func (b *DexAPIBackend) SendTx(ctx context.Context, signedTx *types.Transaction) error {
+	return b.dex.txPool.AddLocal(signedTx)
+}
+
+func (b *DexAPIBackend) GetPoolTransactions() (types.Transactions, error) {
+	pending, err := b.dex.txPool.Pending()
+	if err != nil {
+		return nil, err
+	}
+	var txs types.Transactions
+	for _, batch := range pending {
+		txs = append(txs, batch...)
+	}
+	return txs, nil
+}
+
+func (b *DexAPIBackend) GetPoolTransaction(hash common.Hash) *types.Transaction {
+	return b.dex.txPool.Get(hash)
+}
+
+func (b *DexAPIBackend) GetPoolNonce(ctx context.Context, addr common.Address) (uint64, error) {
+	return b.dex.txPool.State().GetNonce(addr), nil
+}
+
+func (b *DexAPIBackend) Stats() (pending int, queued int) {
+	return b.dex.txPool.Stats()
+}
+
+func (b *DexAPIBackend) TxPoolContent() (map[common.Address]types.Transactions, map[common.Address]types.Transactions) {
+	return b.dex.TxPool().Content()
+}
+
+func (b *DexAPIBackend) SubscribeNewTxsEvent(ch chan<- core.NewTxsEvent) event.Subscription {
+	return b.dex.TxPool().SubscribeNewTxsEvent(ch)
+}
+
+//func (b *DexAPIBackend) Downloader() *downloader.Downloader {
+//	return b.dex.Downloader()
+//}
+
+func (b *DexAPIBackend) ProtocolVersion() int {
+	return b.dex.DexVersion()
+}
+
+func (b *DexAPIBackend) SuggestPrice(ctx context.Context) (*big.Int, error) {
+	return b.gpo.SuggestPrice(ctx)
+}
+
+func (b *DexAPIBackend) ChainDb() ethdb.Database {
+	return b.dex.ChainDb()
+}
+
+func (b *DexAPIBackend) EventMux() *event.TypeMux {
+	return b.dex.EventMux()
+}
+
+func (b *DexAPIBackend) AccountManager() *accounts.Manager {
+	return b.dex.AccountManager()
+}
+
+func (b *DexAPIBackend) BloomStatus() (uint64, uint64) {
+	sections, _, _ := b.dex.bloomIndexer.Sections()
+	return params.BloomBitsBlocks, sections
+}
+
+func (b *DexAPIBackend) ServiceFilter(ctx context.Context, session *bloombits.MatcherSession) {
+	for i := 0; i < bloomFilterThreads; i++ {
+		go session.Multiplex(bloomRetrievalBatch, bloomRetrievalWait, b.dex.bloomRequests)
+	}
+}
diff --git a/dex/backend.go b/dex/backend.go
index b74636de4..3b7fde400 100644
--- a/dex/backend.go
+++ b/dex/backend.go
@@ -48,8 +48,11 @@ type Dexon struct {
 
 	// Channel for shutting down the service
 	shutdownChan chan bool // Channel for shutting down the Ethereum
-	txPool       *core.TxPool
-	blockchain   *core.BlockChain
+
+	// Handlers
+	txPool          *core.TxPool
+	blockchain      *core.BlockChain
+	protocolManager *ProtocolManager
 
 	// DB interfaces
 	chainDb ethdb.Database // Block chain database
@@ -176,3 +179,11 @@ func CreateDB(ctx *node.ServiceContext, config *Config, name string) (ethdb.Data
 	}
 	return db, nil
 }
+
+func (d *Dexon) AccountManager() *accounts.Manager { return d.accountManager }
+func (d *Dexon) BlockChain() *core.BlockChain      { return d.blockchain }
+func (d *Dexon) TxPool() *core.TxPool              { return d.txPool }
+func (d *Dexon) DexVersion() int                   { return int(d.protocolManager.SubProtocols[0].Version) }
+func (d *Dexon) EventMux() *event.TypeMux          { return d.eventMux }
+func (d *Dexon) Engine() consensus.Engine          { return d.engine }
+func (d *Dexon) ChainDb() ethdb.Database           { return d.chainDb }
diff --git a/dex/bloombits.go b/dex/bloombits.go
new file mode 100644
index 000000000..827cae5f4
--- /dev/null
+++ b/dex/bloombits.go
@@ -0,0 +1,138 @@
+// 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 dex
+
+import (
+	"context"
+	"time"
+
+	"github.com/dexon-foundation/dexon/common"
+	"github.com/dexon-foundation/dexon/common/bitutil"
+	"github.com/dexon-foundation/dexon/core"
+	"github.com/dexon-foundation/dexon/core/bloombits"
+	"github.com/dexon-foundation/dexon/core/rawdb"
+	"github.com/dexon-foundation/dexon/core/types"
+	"github.com/dexon-foundation/dexon/ethdb"
+)
+
+const (
+	// bloomServiceThreads is the number of goroutines used globally by an Ethereum
+	// instance to service bloombits lookups for all running filters.
+	bloomServiceThreads = 16
+
+	// bloomFilterThreads is the number of goroutines used locally per filter to
+	// multiplex requests onto the global servicing goroutines.
+	bloomFilterThreads = 3
+
+	// bloomRetrievalBatch is the maximum number of bloom bit retrievals to service
+	// in a single batch.
+	bloomRetrievalBatch = 16
+
+	// bloomRetrievalWait is the maximum time to wait for enough bloom bit requests
+	// to accumulate request an entire batch (avoiding hysteresis).
+	bloomRetrievalWait = time.Duration(0)
+)
+
+// startBloomHandlers starts a batch of goroutines to accept bloom bit database
+// retrievals from possibly a range of filters and serving the data to satisfy.
+func (dex *Dexon) startBloomHandlers(sectionSize uint64) {
+	for i := 0; i < bloomServiceThreads; i++ {
+		go func() {
+			for {
+				select {
+				case <-dex.shutdownChan:
+					return
+
+				case request := <-dex.bloomRequests:
+					task := <-request
+					task.Bitsets = make([][]byte, len(task.Sections))
+					for i, section := range task.Sections {
+						head := rawdb.ReadCanonicalHash(dex.chainDb, (section+1)*sectionSize-1)
+						if compVector, err := rawdb.ReadBloomBits(dex.chainDb, task.Bit, section, head); err == nil {
+							if blob, err := bitutil.DecompressBytes(compVector, int(sectionSize/8)); err == nil {
+								task.Bitsets[i] = blob
+							} else {
+								task.Error = err
+							}
+						} else {
+							task.Error = err
+						}
+					}
+					request <- task
+				}
+			}
+		}()
+	}
+}
+
+const (
+	// bloomThrottling is the time to wait between processing two consecutive index
+	// sections. It's useful during chain upgrades to prevent disk overload.
+	bloomThrottling = 100 * time.Millisecond
+)
+
+// BloomIndexer implements a core.ChainIndexer, building up a rotated bloom bits index
+// for the Ethereum header bloom filters, permitting blazing fast filtering.
+type BloomIndexer struct {
+	size    uint64               // section size to generate bloombits for
+	db      ethdb.Database       // database instance to write index data and metadata into
+	gen     *bloombits.Generator // generator to rotate the bloom bits crating the bloom index
+	section uint64               // Section is the section number being processed currently
+	head    common.Hash          // Head is the hash of the last header processed
+}
+
+// NewBloomIndexer returns a chain indexer that generates bloom bits data for the
+// canonical chain for fast logs filtering.
+func NewBloomIndexer(db ethdb.Database, size, confirms uint64) *core.ChainIndexer {
+	backend := &BloomIndexer{
+		db:   db,
+		size: size,
+	}
+	table := ethdb.NewTable(db, string(rawdb.BloomBitsIndexPrefix))
+
+	return core.NewChainIndexer(db, table, backend, size, confirms, bloomThrottling, "bloombits")
+}
+
+// Reset implements core.ChainIndexerBackend, starting a new bloombits index
+// section.
+func (b *BloomIndexer) Reset(ctx context.Context, section uint64, lastSectionHead common.Hash) error {
+	gen, err := bloombits.NewGenerator(uint(b.size))
+	b.gen, b.section, b.head = gen, section, common.Hash{}
+	return err
+}
+
+// Process implements core.ChainIndexerBackend, adding a new header's bloom into
+// the index.
+func (b *BloomIndexer) Process(ctx context.Context, header *types.Header) error {
+	b.gen.AddBloom(uint(header.Number.Uint64()-b.section*b.size), header.Bloom)
+	b.head = header.Hash()
+	return nil
+}
+
+// Commit implements core.ChainIndexerBackend, finalizing the bloom section and
+// writing it out into the database.
+func (b *BloomIndexer) Commit() error {
+	batch := b.db.NewBatch()
+	for i := 0; i < types.BloomBitLength; i++ {
+		bits, err := b.gen.Bitset(uint(i))
+		if err != nil {
+			return err
+		}
+		rawdb.WriteBloomBits(batch, uint(i), b.section, b.head, bitutil.CompressBytes(bits))
+	}
+	return batch.Write()
+}
diff --git a/dex/gasprice/gasprice.go b/dex/gasprice/gasprice.go
new file mode 100644
index 000000000..9af33c682
--- /dev/null
+++ b/dex/gasprice/gasprice.go
@@ -0,0 +1,189 @@
+// 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 gasprice
+
+import (
+	"context"
+	"math/big"
+	"sort"
+	"sync"
+
+	"github.com/dexon-foundation/dexon/common"
+	"github.com/dexon-foundation/dexon/core/types"
+	"github.com/dexon-foundation/dexon/internal/ethapi"
+	"github.com/dexon-foundation/dexon/params"
+	"github.com/dexon-foundation/dexon/rpc"
+)
+
+var maxPrice = big.NewInt(500 * params.GWei)
+
+type Config struct {
+	Blocks     int
+	Percentile int
+	Default    *big.Int `toml:",omitempty"`
+}
+
+// Oracle recommends gas prices based on the content of recent
+// blocks. Suitable for both light and full clients.
+type Oracle struct {
+	backend   ethapi.Backend
+	lastHead  common.Hash
+	lastPrice *big.Int
+	cacheLock sync.RWMutex
+	fetchLock sync.Mutex
+
+	checkBlocks, maxEmpty, maxBlocks int
+	percentile                       int
+}
+
+// NewOracle returns a new oracle.
+func NewOracle(backend ethapi.Backend, params Config) *Oracle {
+	blocks := params.Blocks
+	if blocks < 1 {
+		blocks = 1
+	}
+	percent := params.Percentile
+	if percent < 0 {
+		percent = 0
+	}
+	if percent > 100 {
+		percent = 100
+	}
+	return &Oracle{
+		backend:     backend,
+		lastPrice:   params.Default,
+		checkBlocks: blocks,
+		maxEmpty:    blocks / 2,
+		maxBlocks:   blocks * 5,
+		percentile:  percent,
+	}
+}
+
+// SuggestPrice returns the recommended gas price.
+func (gpo *Oracle) SuggestPrice(ctx context.Context) (*big.Int, error) {
+	gpo.cacheLock.RLock()
+	lastHead := gpo.lastHead
+	lastPrice := gpo.lastPrice
+	gpo.cacheLock.RUnlock()
+
+	head, _ := gpo.backend.HeaderByNumber(ctx, rpc.LatestBlockNumber)
+	headHash := head.Hash()
+	if headHash == lastHead {
+		return lastPrice, nil
+	}
+
+	gpo.fetchLock.Lock()
+	defer gpo.fetchLock.Unlock()
+
+	// try checking the cache again, maybe the last fetch fetched what we need
+	gpo.cacheLock.RLock()
+	lastHead = gpo.lastHead
+	lastPrice = gpo.lastPrice
+	gpo.cacheLock.RUnlock()
+	if headHash == lastHead {
+		return lastPrice, nil
+	}
+
+	blockNum := head.Number.Uint64()
+	ch := make(chan getBlockPricesResult, gpo.checkBlocks)
+	sent := 0
+	exp := 0
+	var blockPrices []*big.Int
+	for sent < gpo.checkBlocks && blockNum > 0 {
+		go gpo.getBlockPrices(ctx, types.MakeSigner(gpo.backend.ChainConfig(), big.NewInt(int64(blockNum))), blockNum, ch)
+		sent++
+		exp++
+		blockNum--
+	}
+	maxEmpty := gpo.maxEmpty
+	for exp > 0 {
+		res := <-ch
+		if res.err != nil {
+			return lastPrice, res.err
+		}
+		exp--
+		if res.price != nil {
+			blockPrices = append(blockPrices, res.price)
+			continue
+		}
+		if maxEmpty > 0 {
+			maxEmpty--
+			continue
+		}
+		if blockNum > 0 && sent < gpo.maxBlocks {
+			go gpo.getBlockPrices(ctx, types.MakeSigner(gpo.backend.ChainConfig(), big.NewInt(int64(blockNum))), blockNum, ch)
+			sent++
+			exp++
+			blockNum--
+		}
+	}
+	price := lastPrice
+	if len(blockPrices) > 0 {
+		sort.Sort(bigIntArray(blockPrices))
+		price = blockPrices[(len(blockPrices)-1)*gpo.percentile/100]
+	}
+	if price.Cmp(maxPrice) > 0 {
+		price = new(big.Int).Set(maxPrice)
+	}
+
+	gpo.cacheLock.Lock()
+	gpo.lastHead = headHash
+	gpo.lastPrice = price
+	gpo.cacheLock.Unlock()
+	return price, nil
+}
+
+type getBlockPricesResult struct {
+	price *big.Int
+	err   error
+}
+
+type transactionsByGasPrice []*types.Transaction
+
+func (t transactionsByGasPrice) Len() int           { return len(t) }
+func (t transactionsByGasPrice) Swap(i, j int)      { t[i], t[j] = t[j], t[i] }
+func (t transactionsByGasPrice) Less(i, j int) bool { return t[i].GasPrice().Cmp(t[j].GasPrice()) < 0 }
+
+// getBlockPrices calculates the lowest transaction gas price in a given block
+// and sends it to the result channel. If the block is empty, price is nil.
+func (gpo *Oracle) getBlockPrices(ctx context.Context, signer types.Signer, blockNum uint64, ch chan getBlockPricesResult) {
+	block, err := gpo.backend.BlockByNumber(ctx, rpc.BlockNumber(blockNum))
+	if block == nil {
+		ch <- getBlockPricesResult{nil, err}
+		return
+	}
+
+	blockTxs := block.Transactions()
+	txs := make([]*types.Transaction, len(blockTxs))
+	copy(txs, blockTxs)
+	sort.Sort(transactionsByGasPrice(txs))
+
+	for _, tx := range txs {
+		sender, err := types.Sender(signer, tx)
+		if err == nil && sender != block.Coinbase() {
+			ch <- getBlockPricesResult{tx.GasPrice(), nil}
+			return
+		}
+	}
+	ch <- getBlockPricesResult{nil, nil}
+}
+
+type bigIntArray []*big.Int
+
+func (s bigIntArray) Len() int           { return len(s) }
+func (s bigIntArray) Less(i, j int) bool { return s[i].Cmp(s[j]) < 0 }
+func (s bigIntArray) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }