core, light: send chain events using event.Feed (#14865)

10 files changed, 289 insertions, 182 deletions

diff --git a/core/bench_test.go b/core/bench_test.go
index b9250f7d3..ab25c27d3 100644
--- a/core/bench_test.go
+++ b/core/bench_test.go
@@ -30,7 +30,6 @@ import (
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/ethdb"
-	"github.com/ethereum/go-ethereum/event"
 	"github.com/ethereum/go-ethereum/params"
 )
 
@@ -175,8 +174,7 @@ func benchInsertChain(b *testing.B, disk bool, gen func(int, *BlockGen)) {
 
 	// Time the insertion of the new chain.
 	// State and blocks are stored in the same DB.
-	evmux := new(event.TypeMux)
-	chainman, _ := NewBlockChain(db, gspec.Config, ethash.NewFaker(), evmux, vm.Config{})
+	chainman, _ := NewBlockChain(db, gspec.Config, ethash.NewFaker(), vm.Config{})
 	defer chainman.Stop()
 	b.ReportAllocs()
 	b.ResetTimer()
@@ -286,7 +284,7 @@ func benchReadChain(b *testing.B, full bool, count uint64) {
 		if err != nil {
 			b.Fatalf("error opening database at %v: %v", dir, err)
 		}
-		chain, err := NewBlockChain(db, params.TestChainConfig, ethash.NewFaker(), new(event.TypeMux), vm.Config{})
+		chain, err := NewBlockChain(db, params.TestChainConfig, ethash.NewFaker(), vm.Config{})
 		if err != nil {
 			b.Fatalf("error creating chain: %v", err)
 		}
diff --git a/core/block_validator_test.go b/core/block_validator_test.go
index c0afc2955..6d54c2b93 100644
--- a/core/block_validator_test.go
+++ b/core/block_validator_test.go
@@ -25,7 +25,6 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/ethdb"
-	"github.com/ethereum/go-ethereum/event"
 	"github.com/ethereum/go-ethereum/params"
 )
 
@@ -43,7 +42,7 @@ func TestHeaderVerification(t *testing.T) {
 		headers[i] = block.Header()
 	}
 	// Run the header checker for blocks one-by-one, checking for both valid and invalid nonces
-	chain, _ := NewBlockChain(testdb, params.TestChainConfig, ethash.NewFaker(), new(event.TypeMux), vm.Config{})
+	chain, _ := NewBlockChain(testdb, params.TestChainConfig, ethash.NewFaker(), vm.Config{})
 	defer chain.Stop()
 
 	for i := 0; i < len(blocks); i++ {
@@ -107,11 +106,11 @@ func testHeaderConcurrentVerification(t *testing.T, threads int) {
 		var results <-chan error
 
 		if valid {
-			chain, _ := NewBlockChain(testdb, params.TestChainConfig, ethash.NewFaker(), new(event.TypeMux), vm.Config{})
+			chain, _ := NewBlockChain(testdb, params.TestChainConfig, ethash.NewFaker(), vm.Config{})
 			_, results = chain.engine.VerifyHeaders(chain, headers, seals)
 			chain.Stop()
 		} else {
-			chain, _ := NewBlockChain(testdb, params.TestChainConfig, ethash.NewFakeFailer(uint64(len(headers)-1)), new(event.TypeMux), vm.Config{})
+			chain, _ := NewBlockChain(testdb, params.TestChainConfig, ethash.NewFakeFailer(uint64(len(headers)-1)), vm.Config{})
 			_, results = chain.engine.VerifyHeaders(chain, headers, seals)
 			chain.Stop()
 		}
@@ -174,7 +173,7 @@ func testHeaderConcurrentAbortion(t *testing.T, threads int) {
 	defer runtime.GOMAXPROCS(old)
 
 	// Start the verifications and immediately abort
-	chain, _ := NewBlockChain(testdb, params.TestChainConfig, ethash.NewFakeDelayer(time.Millisecond), new(event.TypeMux), vm.Config{})
+	chain, _ := NewBlockChain(testdb, params.TestChainConfig, ethash.NewFakeDelayer(time.Millisecond), vm.Config{})
 	defer chain.Stop()
 
 	abort, results := chain.engine.VerifyHeaders(chain, headers, seals)
diff --git a/core/blockchain.go b/core/blockchain.go
index 3fb8be15f..f3ca4e08c 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -79,10 +79,16 @@ const (
 type BlockChain struct {
 	config *params.ChainConfig // chain & network configuration
 
-	hc           *HeaderChain
-	chainDb      ethdb.Database
-	eventMux     *event.TypeMux
-	genesisBlock *types.Block
+	hc            *HeaderChain
+	chainDb       ethdb.Database
+	rmTxFeed      event.Feed
+	rmLogsFeed    event.Feed
+	chainFeed     event.Feed
+	chainSideFeed event.Feed
+	chainHeadFeed event.Feed
+	logsFeed      event.Feed
+	scope         event.SubscriptionScope
+	genesisBlock  *types.Block
 
 	mu      sync.RWMutex // global mutex for locking chain operations
 	chainmu sync.RWMutex // blockchain insertion lock
@@ -115,7 +121,7 @@ type BlockChain struct {
 // NewBlockChain returns a fully initialised block chain using information
 // available in the database. It initialises the default Ethereum Validator and
 // Processor.
-func NewBlockChain(chainDb ethdb.Database, config *params.ChainConfig, engine consensus.Engine, mux *event.TypeMux, vmConfig vm.Config) (*BlockChain, error) {
+func NewBlockChain(chainDb ethdb.Database, config *params.ChainConfig, engine consensus.Engine, vmConfig vm.Config) (*BlockChain, error) {
 	bodyCache, _ := lru.New(bodyCacheLimit)
 	bodyRLPCache, _ := lru.New(bodyCacheLimit)
 	blockCache, _ := lru.New(blockCacheLimit)
@@ -126,7 +132,6 @@ func NewBlockChain(chainDb ethdb.Database, config *params.ChainConfig, engine co
 		config:       config,
 		chainDb:      chainDb,
 		stateCache:   state.NewDatabase(chainDb),
-		eventMux:     mux,
 		quit:         make(chan struct{}),
 		bodyCache:    bodyCache,
 		bodyRLPCache: bodyRLPCache,
@@ -594,6 +599,8 @@ func (bc *BlockChain) Stop() {
 	if !atomic.CompareAndSwapInt32(&bc.running, 0, 1) {
 		return
 	}
+	// Unsubscribe all subscriptions registered from blockchain
+	bc.scope.Close()
 	close(bc.quit)
 	atomic.StoreInt32(&bc.procInterrupt, 1)
 
@@ -1000,6 +1007,12 @@ func (bc *BlockChain) InsertChain(chain types.Blocks) (int, error) {
 
 			blockInsertTimer.UpdateSince(bstart)
 			events = append(events, ChainEvent{block, block.Hash(), logs})
+			// We need some control over the mining operation. Acquiring locks and waiting
+			// for the miner to create new block takes too long and in most cases isn't
+			// even necessary.
+			if bc.LastBlockHash() == block.Hash() {
+				events = append(events, ChainHeadEvent{block})
+			}
 
 			// Write the positional metadata for transaction and receipt lookups
 			if err := WriteTxLookupEntries(bc.chainDb, block); err != nil {
@@ -1024,7 +1037,7 @@ func (bc *BlockChain) InsertChain(chain types.Blocks) (int, error) {
 		stats.usedGas += usedGas.Uint64()
 		stats.report(chain, i)
 	}
-	go bc.postChainEvents(events, coalescedLogs)
+	go bc.PostChainEvents(events, coalescedLogs)
 
 	return 0, nil
 }
@@ -1184,16 +1197,16 @@ func (bc *BlockChain) reorg(oldBlock, newBlock *types.Block) error {
 	// Must be posted in a goroutine because of the transaction pool trying
 	// to acquire the chain manager lock
 	if len(diff) > 0 {
-		go bc.eventMux.Post(RemovedTransactionEvent{diff})
+		go bc.rmTxFeed.Send(RemovedTransactionEvent{diff})
 	}
 	if len(deletedLogs) > 0 {
-		go bc.eventMux.Post(RemovedLogsEvent{deletedLogs})
+		go bc.rmLogsFeed.Send(RemovedLogsEvent{deletedLogs})
 	}
 
 	if len(oldChain) > 0 {
 		go func() {
 			for _, block := range oldChain {
-				bc.eventMux.Post(ChainSideEvent{Block: block})
+				bc.chainSideFeed.Send(ChainSideEvent{Block: block})
 			}
 		}()
 	}
@@ -1201,22 +1214,25 @@ func (bc *BlockChain) reorg(oldBlock, newBlock *types.Block) error {
 	return nil
 }
 
-// postChainEvents iterates over the events generated by a chain insertion and
-// posts them into the event mux.
-func (bc *BlockChain) postChainEvents(events []interface{}, logs []*types.Log) {
+// PostChainEvents iterates over the events generated by a chain insertion and
+// posts them into the event feed.
+// TODO: Should not expose PostChainEvents. The chain events should be posted in WriteBlock.
+func (bc *BlockChain) PostChainEvents(events []interface{}, logs []*types.Log) {
 	// post event logs for further processing
-	bc.eventMux.Post(logs)
+	if logs != nil {
+		bc.logsFeed.Send(logs)
+	}
 	for _, event := range events {
-		if event, ok := event.(ChainEvent); ok {
-			// We need some control over the mining operation. Acquiring locks and waiting
-			// for the miner to create new block takes too long and in most cases isn't
-			// even necessary.
-			if bc.LastBlockHash() == event.Hash {
-				bc.eventMux.Post(ChainHeadEvent{event.Block})
-			}
+		switch ev := event.(type) {
+		case ChainEvent:
+			bc.chainFeed.Send(ev)
+
+		case ChainHeadEvent:
+			bc.chainHeadFeed.Send(ev)
+
+		case ChainSideEvent:
+			bc.chainSideFeed.Send(ev)
 		}
-		// Fire the insertion events individually too
-		bc.eventMux.Post(event)
 	}
 }
 
@@ -1384,3 +1400,33 @@ func (bc *BlockChain) Config() *params.ChainConfig { return bc.config }
 
 // Engine retrieves the blockchain's consensus engine.
 func (bc *BlockChain) Engine() consensus.Engine { return bc.engine }
+
+// SubscribeRemovedTxEvent registers a subscription of RemovedTransactionEvent.
+func (bc *BlockChain) SubscribeRemovedTxEvent(ch chan<- RemovedTransactionEvent) event.Subscription {
+	return bc.scope.Track(bc.rmTxFeed.Subscribe(ch))
+}
+
+// SubscribeRemovedLogsEvent registers a subscription of RemovedLogsEvent.
+func (bc *BlockChain) SubscribeRemovedLogsEvent(ch chan<- RemovedLogsEvent) event.Subscription {
+	return bc.scope.Track(bc.rmLogsFeed.Subscribe(ch))
+}
+
+// SubscribeChainEvent registers a subscription of ChainEvent.
+func (bc *BlockChain) SubscribeChainEvent(ch chan<- ChainEvent) event.Subscription {
+	return bc.scope.Track(bc.chainFeed.Subscribe(ch))
+}
+
+// SubscribeChainHeadEvent registers a subscription of ChainHeadEvent.
+func (bc *BlockChain) SubscribeChainHeadEvent(ch chan<- ChainHeadEvent) event.Subscription {
+	return bc.scope.Track(bc.chainHeadFeed.Subscribe(ch))
+}
+
+// SubscribeChainSideEvent registers a subscription of ChainSideEvent.
+func (bc *BlockChain) SubscribeChainSideEvent(ch chan<- ChainSideEvent) event.Subscription {
+	return bc.scope.Track(bc.chainSideFeed.Subscribe(ch))
+}
+
+// SubscribeLogsEvent registers a subscription of []*types.Log.
+func (bc *BlockChain) SubscribeLogsEvent(ch chan<- []*types.Log) event.Subscription {
+	return bc.scope.Track(bc.logsFeed.Subscribe(ch))
+}
diff --git a/core/blockchain_test.go b/core/blockchain_test.go
index 4a0f44940..470974a0a 100644
--- a/core/blockchain_test.go
+++ b/core/blockchain_test.go
@@ -31,7 +31,6 @@ import (
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/ethdb"
-	"github.com/ethereum/go-ethereum/event"
 	"github.com/ethereum/go-ethereum/params"
 )
 
@@ -47,7 +46,7 @@ func newTestBlockChain(fake bool) *BlockChain {
 	if !fake {
 		engine = ethash.NewTester()
 	}
-	blockchain, err := NewBlockChain(db, gspec.Config, engine, new(event.TypeMux), vm.Config{})
+	blockchain, err := NewBlockChain(db, gspec.Config, engine, vm.Config{})
 	if err != nil {
 		panic(err)
 	}
@@ -497,7 +496,7 @@ func testReorgBadHashes(t *testing.T, full bool) {
 	}
 
 	// Create a new BlockChain and check that it rolled back the state.
-	ncm, err := NewBlockChain(bc.chainDb, bc.config, ethash.NewFaker(), new(event.TypeMux), vm.Config{})
+	ncm, err := NewBlockChain(bc.chainDb, bc.config, ethash.NewFaker(), vm.Config{})
 	if err != nil {
 		t.Fatalf("failed to create new chain manager: %v", err)
 	}
@@ -610,7 +609,7 @@ func TestFastVsFullChains(t *testing.T) {
 	// Import the chain as an archive node for the comparison baseline
 	archiveDb, _ := ethdb.NewMemDatabase()
 	gspec.MustCommit(archiveDb)
-	archive, _ := NewBlockChain(archiveDb, gspec.Config, ethash.NewFaker(), new(event.TypeMux), vm.Config{})
+	archive, _ := NewBlockChain(archiveDb, gspec.Config, ethash.NewFaker(), vm.Config{})
 	defer archive.Stop()
 
 	if n, err := archive.InsertChain(blocks); err != nil {
@@ -619,7 +618,7 @@ func TestFastVsFullChains(t *testing.T) {
 	// Fast import the chain as a non-archive node to test
 	fastDb, _ := ethdb.NewMemDatabase()
 	gspec.MustCommit(fastDb)
-	fast, _ := NewBlockChain(fastDb, gspec.Config, ethash.NewFaker(), new(event.TypeMux), vm.Config{})
+	fast, _ := NewBlockChain(fastDb, gspec.Config, ethash.NewFaker(), vm.Config{})
 	defer fast.Stop()
 
 	headers := make([]*types.Header, len(blocks))
@@ -697,7 +696,7 @@ func TestLightVsFastVsFullChainHeads(t *testing.T) {
 	archiveDb, _ := ethdb.NewMemDatabase()
 	gspec.MustCommit(archiveDb)
 
-	archive, _ := NewBlockChain(archiveDb, gspec.Config, ethash.NewFaker(), new(event.TypeMux), vm.Config{})
+	archive, _ := NewBlockChain(archiveDb, gspec.Config, ethash.NewFaker(), vm.Config{})
 	if n, err := archive.InsertChain(blocks); err != nil {
 		t.Fatalf("failed to process block %d: %v", n, err)
 	}
@@ -710,7 +709,7 @@ func TestLightVsFastVsFullChainHeads(t *testing.T) {
 	// Import the chain as a non-archive node and ensure all pointers are updated
 	fastDb, _ := ethdb.NewMemDatabase()
 	gspec.MustCommit(fastDb)
-	fast, _ := NewBlockChain(fastDb, gspec.Config, ethash.NewFaker(), new(event.TypeMux), vm.Config{})
+	fast, _ := NewBlockChain(fastDb, gspec.Config, ethash.NewFaker(), vm.Config{})
 	defer fast.Stop()
 
 	headers := make([]*types.Header, len(blocks))
@@ -731,7 +730,7 @@ func TestLightVsFastVsFullChainHeads(t *testing.T) {
 	lightDb, _ := ethdb.NewMemDatabase()
 	gspec.MustCommit(lightDb)
 
-	light, _ := NewBlockChain(lightDb, gspec.Config, ethash.NewFaker(), new(event.TypeMux), vm.Config{})
+	light, _ := NewBlockChain(lightDb, gspec.Config, ethash.NewFaker(), vm.Config{})
 	if n, err := light.InsertHeaderChain(headers, 1); err != nil {
 		t.Fatalf("failed to insert header %d: %v", n, err)
 	}
@@ -800,8 +799,7 @@ func TestChainTxReorgs(t *testing.T) {
 		}
 	})
 	// Import the chain. This runs all block validation rules.
-	evmux := &event.TypeMux{}
-	blockchain, _ := NewBlockChain(db, gspec.Config, ethash.NewFaker(), evmux, vm.Config{})
+	blockchain, _ := NewBlockChain(db, gspec.Config, ethash.NewFaker(), vm.Config{})
 	if i, err := blockchain.InsertChain(chain); err != nil {
 		t.Fatalf("failed to insert original chain[%d]: %v", i, err)
 	}
@@ -872,11 +870,11 @@ func TestLogReorgs(t *testing.T) {
 		signer  = types.NewEIP155Signer(gspec.Config.ChainId)
 	)
 
-	var evmux event.TypeMux
-	blockchain, _ := NewBlockChain(db, gspec.Config, ethash.NewFaker(), &evmux, vm.Config{})
+	blockchain, _ := NewBlockChain(db, gspec.Config, ethash.NewFaker(), vm.Config{})
 	defer blockchain.Stop()
 
-	subs := evmux.Subscribe(RemovedLogsEvent{})
+	rmLogsCh := make(chan RemovedLogsEvent)
+	blockchain.SubscribeRemovedLogsEvent(rmLogsCh)
 	chain, _ := GenerateChain(params.TestChainConfig, genesis, db, 2, func(i int, gen *BlockGen) {
 		if i == 1 {
 			tx, err := types.SignTx(types.NewContractCreation(gen.TxNonce(addr1), new(big.Int), big.NewInt(1000000), new(big.Int), code), signer, key1)
@@ -895,9 +893,14 @@ func TestLogReorgs(t *testing.T) {
 		t.Fatalf("failed to insert forked chain: %v", err)
 	}
 
-	ev := <-subs.Chan()
-	if len(ev.Data.(RemovedLogsEvent).Logs) == 0 {
-		t.Error("expected logs")
+	timeout := time.NewTimer(1 * time.Second)
+	select {
+	case ev := <-rmLogsCh:
+		if len(ev.Logs) == 0 {
+			t.Error("expected logs")
+		}
+	case <-timeout.C:
+		t.Fatal("Timeout. There is no RemovedLogsEvent has been sent.")
 	}
 }
 
@@ -914,8 +917,7 @@ func TestReorgSideEvent(t *testing.T) {
 		signer  = types.NewEIP155Signer(gspec.Config.ChainId)
 	)
 
-	evmux := &event.TypeMux{}
-	blockchain, _ := NewBlockChain(db, gspec.Config, ethash.NewFaker(), evmux, vm.Config{})
+	blockchain, _ := NewBlockChain(db, gspec.Config, ethash.NewFaker(), vm.Config{})
 	defer blockchain.Stop()
 
 	chain, _ := GenerateChain(gspec.Config, genesis, db, 3, func(i int, gen *BlockGen) {})
@@ -933,7 +935,8 @@ func TestReorgSideEvent(t *testing.T) {
 		}
 		gen.AddTx(tx)
 	})
-	subs := evmux.Subscribe(ChainSideEvent{})
+	chainSideCh := make(chan ChainSideEvent)
+	blockchain.SubscribeChainSideEvent(chainSideCh)
 	if _, err := blockchain.InsertChain(replacementBlocks); err != nil {
 		t.Fatalf("failed to insert chain: %v", err)
 	}
@@ -956,8 +959,8 @@ func TestReorgSideEvent(t *testing.T) {
 done:
 	for {
 		select {
-		case ev := <-subs.Chan():
-			block := ev.Data.(ChainSideEvent).Block
+		case ev := <-chainSideCh:
+			block := ev.Block
 			if _, ok := expectedSideHashes[block.Hash()]; !ok {
 				t.Errorf("%d: didn't expect %x to be in side chain", i, block.Hash())
 			}
@@ -977,7 +980,7 @@ done:
 
 	// make sure no more events are fired
 	select {
-	case e := <-subs.Chan():
+	case e := <-chainSideCh:
 		t.Errorf("unexpected event fired: %v", e)
 	case <-time.After(250 * time.Millisecond):
 	}
@@ -1038,10 +1041,9 @@ func TestEIP155Transition(t *testing.T) {
 			Alloc:  GenesisAlloc{address: {Balance: funds}, deleteAddr: {Balance: new(big.Int)}},
 		}
 		genesis = gspec.MustCommit(db)
-		mux     event.TypeMux
 	)
 
-	blockchain, _ := NewBlockChain(db, gspec.Config, ethash.NewFaker(), &mux, vm.Config{})
+	blockchain, _ := NewBlockChain(db, gspec.Config, ethash.NewFaker(), vm.Config{})
 	defer blockchain.Stop()
 
 	blocks, _ := GenerateChain(gspec.Config, genesis, db, 4, func(i int, block *BlockGen) {
@@ -1148,9 +1150,8 @@ func TestEIP161AccountRemoval(t *testing.T) {
 			Alloc: GenesisAlloc{address: {Balance: funds}},
 		}
 		genesis = gspec.MustCommit(db)
-		mux     event.TypeMux
 	)
-	blockchain, _ := NewBlockChain(db, gspec.Config, ethash.NewFaker(), &mux, vm.Config{})
+	blockchain, _ := NewBlockChain(db, gspec.Config, ethash.NewFaker(), vm.Config{})
 	defer blockchain.Stop()
 
 	blocks, _ := GenerateChain(gspec.Config, genesis, db, 3, func(i int, block *BlockGen) {
diff --git a/core/chain_makers.go b/core/chain_makers.go
index 976a8114d..cb5825d18 100644
--- a/core/chain_makers.go
+++ b/core/chain_makers.go
@@ -27,7 +27,6 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/ethdb"
-	"github.com/ethereum/go-ethereum/event"
 	"github.com/ethereum/go-ethereum/params"
 )
 
@@ -236,7 +235,7 @@ func newCanonical(n int, full bool) (ethdb.Database, *BlockChain, error) {
 	db, _ := ethdb.NewMemDatabase()
 	genesis := gspec.MustCommit(db)
 
-	blockchain, _ := NewBlockChain(db, params.AllProtocolChanges, ethash.NewFaker(), new(event.TypeMux), vm.Config{})
+	blockchain, _ := NewBlockChain(db, params.AllProtocolChanges, ethash.NewFaker(), vm.Config{})
 	// Create and inject the requested chain
 	if n == 0 {
 		return db, blockchain, nil
diff --git a/core/chain_makers_test.go b/core/chain_makers_test.go
index 28eb76c63..2260c62fb 100644
--- a/core/chain_makers_test.go
+++ b/core/chain_makers_test.go
@@ -25,7 +25,6 @@ import (
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/ethdb"
-	"github.com/ethereum/go-ethereum/event"
 	"github.com/ethereum/go-ethereum/params"
 )
 
@@ -80,9 +79,7 @@ func ExampleGenerateChain() {
 	})
 
 	// Import the chain. This runs all block validation rules.
-	evmux := &event.TypeMux{}
-
-	blockchain, _ := NewBlockChain(db, gspec.Config, ethash.NewFaker(), evmux, vm.Config{})
+	blockchain, _ := NewBlockChain(db, gspec.Config, ethash.NewFaker(), vm.Config{})
 	defer blockchain.Stop()
 
 	if i, err := blockchain.InsertChain(chain); err != nil {
diff --git a/core/dao_test.go b/core/dao_test.go
index 99bf1ecae..d6e11d78a 100644
--- a/core/dao_test.go
+++ b/core/dao_test.go
@@ -23,7 +23,6 @@ import (
 	"github.com/ethereum/go-ethereum/consensus/ethash"
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/ethdb"
-	"github.com/ethereum/go-ethereum/event"
 	"github.com/ethereum/go-ethereum/params"
 )
 
@@ -42,13 +41,13 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 	proDb, _ := ethdb.NewMemDatabase()
 	gspec.MustCommit(proDb)
 	proConf := &params.ChainConfig{HomesteadBlock: big.NewInt(0), DAOForkBlock: forkBlock, DAOForkSupport: true}
-	proBc, _ := NewBlockChain(proDb, proConf, ethash.NewFaker(), new(event.TypeMux), vm.Config{})
+	proBc, _ := NewBlockChain(proDb, proConf, ethash.NewFaker(), vm.Config{})
 	defer proBc.Stop()
 
 	conDb, _ := ethdb.NewMemDatabase()
 	gspec.MustCommit(conDb)
 	conConf := &params.ChainConfig{HomesteadBlock: big.NewInt(0), DAOForkBlock: forkBlock, DAOForkSupport: false}
-	conBc, _ := NewBlockChain(conDb, conConf, ethash.NewFaker(), new(event.TypeMux), vm.Config{})
+	conBc, _ := NewBlockChain(conDb, conConf, ethash.NewFaker(), vm.Config{})
 	defer conBc.Stop()
 
 	if _, err := proBc.InsertChain(prefix); err != nil {
@@ -62,8 +61,7 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 		// Create a pro-fork block, and try to feed into the no-fork chain
 		db, _ = ethdb.NewMemDatabase()
 		gspec.MustCommit(db)
-
-		bc, _ := NewBlockChain(db, conConf, ethash.NewFaker(), new(event.TypeMux), vm.Config{})
+		bc, _ := NewBlockChain(db, conConf, ethash.NewFaker(), vm.Config{})
 		defer bc.Stop()
 
 		blocks := conBc.GetBlocksFromHash(conBc.CurrentBlock().Hash(), int(conBc.CurrentBlock().NumberU64()))
@@ -85,8 +83,7 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 		// Create a no-fork block, and try to feed into the pro-fork chain
 		db, _ = ethdb.NewMemDatabase()
 		gspec.MustCommit(db)
-
-		bc, _ = NewBlockChain(db, proConf, ethash.NewFaker(), new(event.TypeMux), vm.Config{})
+		bc, _ = NewBlockChain(db, proConf, ethash.NewFaker(), vm.Config{})
 		defer bc.Stop()
 
 		blocks = proBc.GetBlocksFromHash(proBc.CurrentBlock().Hash(), int(proBc.CurrentBlock().NumberU64()))
@@ -109,8 +106,7 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 	// Verify that contra-forkers accept pro-fork extra-datas after forking finishes
 	db, _ = ethdb.NewMemDatabase()
 	gspec.MustCommit(db)
-
-	bc, _ := NewBlockChain(db, conConf, ethash.NewFaker(), new(event.TypeMux), vm.Config{})
+	bc, _ := NewBlockChain(db, conConf, ethash.NewFaker(), vm.Config{})
 	defer bc.Stop()
 
 	blocks := conBc.GetBlocksFromHash(conBc.CurrentBlock().Hash(), int(conBc.CurrentBlock().NumberU64()))
@@ -127,8 +123,7 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 	// Verify that pro-forkers accept contra-fork extra-datas after forking finishes
 	db, _ = ethdb.NewMemDatabase()
 	gspec.MustCommit(db)
-
-	bc, _ = NewBlockChain(db, proConf, ethash.NewFaker(), new(event.TypeMux), vm.Config{})
+	bc, _ = NewBlockChain(db, proConf, ethash.NewFaker(), vm.Config{})
 	defer bc.Stop()
 
 	blocks = proBc.GetBlocksFromHash(proBc.CurrentBlock().Hash(), int(proBc.CurrentBlock().NumberU64()))
diff --git a/core/genesis_test.go b/core/genesis_test.go
index 8b193759f..482f86190 100644
--- a/core/genesis_test.go
+++ b/core/genesis_test.go
@@ -26,7 +26,6 @@ import (
 	"github.com/ethereum/go-ethereum/consensus/ethash"
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/ethdb"
-	"github.com/ethereum/go-ethereum/event"
 	"github.com/ethereum/go-ethereum/params"
 )
 
@@ -119,9 +118,8 @@ func TestSetupGenesis(t *testing.T) {
 				// Commit the 'old' genesis block with Homestead transition at #2.
 				// Advance to block #4, past the homestead transition block of customg.
 				genesis := oldcustomg.MustCommit(db)
-				bc, _ := NewBlockChain(db, oldcustomg.Config, ethash.NewFullFaker(), new(event.TypeMux), vm.Config{})
+				bc, _ := NewBlockChain(db, oldcustomg.Config, ethash.NewFullFaker(), vm.Config{})
 				defer bc.Stop()
-
 				bc.SetValidator(bproc{})
 				bc.InsertChain(makeBlockChainWithDiff(genesis, []int{2, 3, 4, 5}, 0))
 				bc.CurrentBlock()
diff --git a/core/tx_pool.go b/core/tx_pool.go
index b0c251f92..d835c94d1 100644
--- a/core/tx_pool.go
+++ b/core/tx_pool.go
@@ -34,6 +34,13 @@ import (
 	"gopkg.in/karalabe/cookiejar.v2/collections/prque"
 )
 
+const (
+	// chainHeadChanSize is the size of channel listening to ChainHeadEvent.
+	chainHeadChanSize = 10
+	// rmTxChanSize is the size of channel listening to RemovedTransactionEvent.
+	rmTxChanSize = 10
+)
+
 var (
 	// ErrInvalidSender is returned if the transaction contains an invalid signature.
 	ErrInvalidSender = errors.New("invalid sender")
@@ -95,7 +102,14 @@ var (
 	underpricedTxCounter = metrics.NewCounter("txpool/underpriced")
 )
 
-type stateFn func() (*state.StateDB, error)
+// blockChain provides the state of blockchain and current gas limit to do
+// some pre checks in tx pool and event subscribers.
+type blockChain interface {
+	State() (*state.StateDB, error)
+	GasLimit() *big.Int
+	SubscribeChainHeadEvent(ch chan<- ChainHeadEvent) event.Subscription
+	SubscribeRemovedTxEvent(ch chan<- RemovedTransactionEvent) event.Subscription
+}
 
 // TxPoolConfig are the configuration parameters of the transaction pool.
 type TxPoolConfig struct {
@@ -160,12 +174,15 @@ func (config *TxPoolConfig) sanitize() TxPoolConfig {
 type TxPool struct {
 	config       TxPoolConfig
 	chainconfig  *params.ChainConfig
-	currentState stateFn // The state function which will allow us to do some pre checks
+	blockChain   blockChain
 	pendingState *state.ManagedState
-	gasLimit     func() *big.Int // The current gas limit function callback
 	gasPrice     *big.Int
-	eventMux     *event.TypeMux
-	events       *event.TypeMuxSubscription
+	txFeed       event.Feed
+	scope        event.SubscriptionScope
+	chainHeadCh  chan ChainHeadEvent
+	chainHeadSub event.Subscription
+	rmTxCh       chan RemovedTransactionEvent
+	rmTxSub      event.Subscription
 	signer       types.Signer
 	mu           sync.RWMutex
 
@@ -185,7 +202,7 @@ type TxPool struct {
 
 // NewTxPool creates a new transaction pool to gather, sort and filter inbound
 // trnsactions from the network.
-func NewTxPool(config TxPoolConfig, chainconfig *params.ChainConfig, eventMux *event.TypeMux, currentStateFn stateFn, gasLimitFn func() *big.Int) *TxPool {
+func NewTxPool(config TxPoolConfig, chainconfig *params.ChainConfig, blockChain blockChain) *TxPool {
 	// Sanitize the input to ensure no vulnerable gas prices are set
 	config = (&config).sanitize()
 
@@ -193,17 +210,16 @@ func NewTxPool(config TxPoolConfig, chainconfig *params.ChainConfig, eventMux *e
 	pool := &TxPool{
 		config:       config,
 		chainconfig:  chainconfig,
+		blockChain:   blockChain,
 		signer:       types.NewEIP155Signer(chainconfig.ChainId),
 		pending:      make(map[common.Address]*txList),
 		queue:        make(map[common.Address]*txList),
 		beats:        make(map[common.Address]time.Time),
 		all:          make(map[common.Hash]*types.Transaction),
-		eventMux:     eventMux,
-		currentState: currentStateFn,
-		gasLimit:     gasLimitFn,
+		chainHeadCh:  make(chan ChainHeadEvent, chainHeadChanSize),
+		rmTxCh:       make(chan RemovedTransactionEvent, rmTxChanSize),
 		gasPrice:     new(big.Int).SetUint64(config.PriceLimit),
 		pendingState: nil,
-		events:       eventMux.Subscribe(ChainHeadEvent{}, RemovedTransactionEvent{}),
 	}
 	pool.locals = newAccountSet(pool.signer)
 	pool.priced = newTxPricedList(&pool.all)
@@ -220,6 +236,9 @@ func NewTxPool(config TxPoolConfig, chainconfig *params.ChainConfig, eventMux *e
 			log.Warn("Failed to rotate transaction journal", "err", err)
 		}
 	}
+	// Subscribe events from blockchain
+	pool.chainHeadSub = pool.blockChain.SubscribeChainHeadEvent(pool.chainHeadCh)
+	pool.rmTxSub = pool.blockChain.SubscribeRemovedTxEvent(pool.rmTxCh)
 	// Start the event loop and return
 	pool.wg.Add(1)
 	go pool.loop()
@@ -248,25 +267,27 @@ func (pool *TxPool) loop() {
 	// Keep waiting for and reacting to the various events
 	for {
 		select {
-		// Handle any events fired by the system
-		case ev, ok := <-pool.events.Chan():
-			if !ok {
-				return
-			}
-			switch ev := ev.Data.(type) {
-			case ChainHeadEvent:
-				pool.mu.Lock()
-				if ev.Block != nil {
-					if pool.chainconfig.IsHomestead(ev.Block.Number()) {
-						pool.homestead = true
-					}
+		// Handle ChainHeadEvent
+		case ev := <-pool.chainHeadCh:
+			pool.mu.Lock()
+			if ev.Block != nil {
+				if pool.chainconfig.IsHomestead(ev.Block.Number()) {
+					pool.homestead = true
 				}
-				pool.reset()
-				pool.mu.Unlock()
 
-			case RemovedTransactionEvent:
-				pool.addTxs(ev.Txs, false)
 			}
+			pool.reset()
+			pool.mu.Unlock()
+		// Be unsubscribed due to system stopped
+		case <-pool.chainHeadSub.Err():
+			return
+
+		// Handle RemovedTransactionEvent
+		case ev := <-pool.rmTxCh:
+			pool.addTxs(ev.Txs, false)
+		// Be unsubscribed due to system stopped
+		case <-pool.rmTxSub.Err():
+			return
 
 		// Handle stats reporting ticks
 		case <-report.C:
@@ -322,7 +343,7 @@ func (pool *TxPool) lockedReset() {
 // reset retrieves the current state of the blockchain and ensures the content
 // of the transaction pool is valid with regard to the chain state.
 func (pool *TxPool) reset() {
-	currentState, err := pool.currentState()
+	currentState, err := pool.blockChain.State()
 	if err != nil {
 		log.Error("Failed reset txpool state", "err", err)
 		return
@@ -347,7 +368,11 @@ func (pool *TxPool) reset() {
 
 // Stop terminates the transaction pool.
 func (pool *TxPool) Stop() {
-	pool.events.Unsubscribe()
+	// Unsubscribe all subscriptions registered from txpool
+	pool.scope.Close()
+	// Unsubscribe subscriptions registered from blockchain
+	pool.chainHeadSub.Unsubscribe()
+	pool.rmTxSub.Unsubscribe()
 	pool.wg.Wait()
 
 	if pool.journal != nil {
@@ -356,6 +381,12 @@ func (pool *TxPool) Stop() {
 	log.Info("Transaction pool stopped")
 }
 
+// SubscribeTxPreEvent registers a subscription of TxPreEvent and
+// starts sending event to the given channel.
+func (pool *TxPool) SubscribeTxPreEvent(ch chan<- TxPreEvent) event.Subscription {
+	return pool.scope.Track(pool.txFeed.Subscribe(ch))
+}
+
 // GasPrice returns the current gas price enforced by the transaction pool.
 func (pool *TxPool) GasPrice() *big.Int {
 	pool.mu.RLock()
@@ -468,7 +499,7 @@ func (pool *TxPool) validateTx(tx *types.Transaction, local bool) error {
 		return ErrNegativeValue
 	}
 	// Ensure the transaction doesn't exceed the current block limit gas.
-	if pool.gasLimit().Cmp(tx.Gas()) < 0 {
+	if pool.blockChain.GasLimit().Cmp(tx.Gas()) < 0 {
 		return ErrGasLimit
 	}
 	// Make sure the transaction is signed properly
@@ -482,7 +513,7 @@ func (pool *TxPool) validateTx(tx *types.Transaction, local bool) error {
 		return ErrUnderpriced
 	}
 	// Ensure the transaction adheres to nonce ordering
-	currentState, err := pool.currentState()
+	currentState, err := pool.blockChain.State()
 	if err != nil {
 		return err
 	}
@@ -647,7 +678,7 @@ func (pool *TxPool) promoteTx(addr common.Address, hash common.Hash, tx *types.T
 	// Set the potentially new pending nonce and notify any subsystems of the new tx
 	pool.beats[addr] = time.Now()
 	pool.pendingState.SetNonce(addr, tx.Nonce()+1)
-	go pool.eventMux.Post(TxPreEvent{tx})
+	go pool.txFeed.Send(TxPreEvent{tx})
 }
 
 // AddLocal enqueues a single transaction into the pool if it is valid, marking
@@ -690,7 +721,7 @@ func (pool *TxPool) addTx(tx *types.Transaction, local bool) error {
 	}
 	// If we added a new transaction, run promotion checks and return
 	if !replace {
-		state, err := pool.currentState()
+		state, err := pool.blockChain.State()
 		if err != nil {
 			return err
 		}
@@ -717,7 +748,7 @@ func (pool *TxPool) addTxs(txs []*types.Transaction, local bool) error {
 	}
 	// Only reprocess the internal state if something was actually added
 	if len(dirty) > 0 {
-		state, err := pool.currentState()
+		state, err := pool.blockChain.State()
 		if err != nil {
 			return err
 		}
@@ -804,7 +835,7 @@ func (pool *TxPool) removeTx(hash common.Hash) {
 // future queue to the set of pending transactions. During this process, all
 // invalidated transactions (low nonce, low balance) are deleted.
 func (pool *TxPool) promoteExecutables(state *state.StateDB, accounts []common.Address) {
-	gaslimit := pool.gasLimit()
+	gaslimit := pool.blockChain.GasLimit()
 
 	// Gather all the accounts potentially needing updates
 	if accounts == nil {
@@ -973,7 +1004,7 @@ func (pool *TxPool) promoteExecutables(state *state.StateDB, accounts []common.A
 // executable/pending queue and any subsequent transactions that become unexecutable
 // are moved back into the future queue.
 func (pool *TxPool) demoteUnexecutables(state *state.StateDB) {
-	gaslimit := pool.gasLimit()
+	gaslimit := pool.blockChain.GasLimit()
 
 	// Iterate over all accounts and demote any non-executable transactions
 	for addr, list := range pool.pending {
diff --git a/core/tx_pool_test.go b/core/tx_pool_test.go
index fcb330051..ee1ddd4bb 100644
--- a/core/tx_pool_test.go
+++ b/core/tx_pool_test.go
@@ -44,6 +44,29 @@ func init() {
 	testTxPoolConfig.Journal = ""
 }
 
+type testBlockChain struct {
+	statedb       *state.StateDB
+	gasLimit      *big.Int
+	chainHeadFeed *event.Feed
+	rmTxFeed      *event.Feed
+}
+
+func (bc *testBlockChain) State() (*state.StateDB, error) {
+	return bc.statedb, nil
+}
+
+func (bc *testBlockChain) GasLimit() *big.Int {
+	return new(big.Int).Set(bc.gasLimit)
+}
+
+func (bc *testBlockChain) SubscribeChainHeadEvent(ch chan<- ChainHeadEvent) event.Subscription {
+	return bc.chainHeadFeed.Subscribe(ch)
+}
+
+func (bc *testBlockChain) SubscribeRemovedTxEvent(ch chan<- RemovedTransactionEvent) event.Subscription {
+	return bc.rmTxFeed.Subscribe(ch)
+}
+
 func transaction(nonce uint64, gaslimit *big.Int, key *ecdsa.PrivateKey) *types.Transaction {
 	return pricedTransaction(nonce, gaslimit, big.NewInt(1), key)
 }
@@ -56,9 +79,10 @@ func pricedTransaction(nonce uint64, gaslimit, gasprice *big.Int, key *ecdsa.Pri
 func setupTxPool() (*TxPool, *ecdsa.PrivateKey) {
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed), new(event.Feed)}
 
 	key, _ := crypto.GenerateKey()
-	pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, new(event.TypeMux), func() (*state.StateDB, error) { return statedb, nil }, func() *big.Int { return big.NewInt(1000000) })
+	pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)
 
 	return pool, key
 }
@@ -96,6 +120,31 @@ func deriveSender(tx *types.Transaction) (common.Address, error) {
 	return types.Sender(types.HomesteadSigner{}, tx)
 }
 
+type testChain struct {
+	*testBlockChain
+	address common.Address
+	trigger *bool
+}
+
+// testChain.State() is used multiple times to reset the pending state.
+// when simulate is true it will create a state that indicates
+// that tx0 and tx1 are included in the chain.
+func (c *testChain) State() (*state.StateDB, error) {
+	// delay "state change" by one. The tx pool fetches the
+	// state multiple times and by delaying it a bit we simulate
+	// a state change between those fetches.
+	stdb := c.statedb
+	if *c.trigger {
+		db, _ := ethdb.NewMemDatabase()
+		c.statedb, _ = state.New(common.Hash{}, state.NewDatabase(db))
+		// simulate that the new head block included tx0 and tx1
+		c.statedb.SetNonce(c.address, 2)
+		c.statedb.SetBalance(c.address, new(big.Int).SetUint64(params.Ether))
+		*c.trigger = false
+	}
+	return stdb, nil
+}
+
 // This test simulates a scenario where a new block is imported during a
 // state reset and tests whether the pending state is in sync with the
 // block head event that initiated the resetState().
@@ -104,38 +153,18 @@ func TestStateChangeDuringPoolReset(t *testing.T) {
 		db, _      = ethdb.NewMemDatabase()
 		key, _     = crypto.GenerateKey()
 		address    = crypto.PubkeyToAddress(key.PublicKey)
-		mux        = new(event.TypeMux)
 		statedb, _ = state.New(common.Hash{}, state.NewDatabase(db))
 		trigger    = false
 	)
 
 	// setup pool with 2 transaction in it
 	statedb.SetBalance(address, new(big.Int).SetUint64(params.Ether))
+	blockchain := &testChain{&testBlockChain{statedb, big.NewInt(1000000000), new(event.Feed), new(event.Feed)}, address, &trigger}
 
 	tx0 := transaction(0, big.NewInt(100000), key)
 	tx1 := transaction(1, big.NewInt(100000), key)
 
-	// stateFunc is used multiple times to reset the pending state.
-	// when simulate is true it will create a state that indicates
-	// that tx0 and tx1 are included in the chain.
-	stateFunc := func() (*state.StateDB, error) {
-		// delay "state change" by one. The tx pool fetches the
-		// state multiple times and by delaying it a bit we simulate
-		// a state change between those fetches.
-		stdb := statedb
-		if trigger {
-			statedb, _ = state.New(common.Hash{}, state.NewDatabase(db))
-			// simulate that the new head block included tx0 and tx1
-			statedb.SetNonce(address, 2)
-			statedb.SetBalance(address, new(big.Int).SetUint64(params.Ether))
-			trigger = false
-		}
-		return stdb, nil
-	}
-
-	gasLimitFunc := func() *big.Int { return big.NewInt(1000000000) }
-
-	pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, mux, stateFunc, gasLimitFunc)
+	pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)
 	defer pool.Stop()
 
 	nonce := pool.State().GetNonce(address)
@@ -176,7 +205,7 @@ func TestInvalidTransactions(t *testing.T) {
 
 	tx := transaction(0, big.NewInt(100), key)
 	from, _ := deriveSender(tx)
-	currentState, _ := pool.currentState()
+	currentState, _ := pool.blockChain.State()
 	currentState.AddBalance(from, big.NewInt(1))
 	if err := pool.AddRemote(tx); err != ErrInsufficientFunds {
 		t.Error("expected", ErrInsufficientFunds)
@@ -211,7 +240,7 @@ func TestTransactionQueue(t *testing.T) {
 
 	tx := transaction(0, big.NewInt(100), key)
 	from, _ := deriveSender(tx)
-	currentState, _ := pool.currentState()
+	currentState, _ := pool.blockChain.State()
 	currentState.AddBalance(from, big.NewInt(1000))
 	pool.lockedReset()
 	pool.enqueueTx(tx.Hash(), tx)
@@ -241,7 +270,7 @@ func TestTransactionQueue(t *testing.T) {
 	tx2 := transaction(10, big.NewInt(100), key)
 	tx3 := transaction(11, big.NewInt(100), key)
 	from, _ = deriveSender(tx1)
-	currentState, _ = pool.currentState()
+	currentState, _ = pool.blockChain.State()
 	currentState.AddBalance(from, big.NewInt(1000))
 	pool.lockedReset()
 
@@ -264,7 +293,7 @@ func TestRemoveTx(t *testing.T) {
 	defer pool.Stop()
 
 	addr := crypto.PubkeyToAddress(key.PublicKey)
-	currentState, _ := pool.currentState()
+	currentState, _ := pool.blockChain.State()
 	currentState.AddBalance(addr, big.NewInt(1))
 
 	tx1 := transaction(0, big.NewInt(100), key)
@@ -296,7 +325,7 @@ func TestNegativeValue(t *testing.T) {
 
 	tx, _ := types.SignTx(types.NewTransaction(0, common.Address{}, big.NewInt(-1), big.NewInt(100), big.NewInt(1), nil), types.HomesteadSigner{}, key)
 	from, _ := deriveSender(tx)
-	currentState, _ := pool.currentState()
+	currentState, _ := pool.blockChain.State()
 	currentState.AddBalance(from, big.NewInt(1))
 	if err := pool.AddRemote(tx); err != ErrNegativeValue {
 		t.Error("expected", ErrNegativeValue, "got", err)
@@ -311,8 +340,8 @@ func TestTransactionChainFork(t *testing.T) {
 	resetState := func() {
 		db, _ := ethdb.NewMemDatabase()
 		statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
-		pool.currentState = func() (*state.StateDB, error) { return statedb, nil }
-		currentState, _ := pool.currentState()
+		pool.blockChain = &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed), new(event.Feed)}
+		currentState, _ := pool.blockChain.State()
 		currentState.AddBalance(addr, big.NewInt(100000000000000))
 		pool.lockedReset()
 	}
@@ -339,8 +368,8 @@ func TestTransactionDoubleNonce(t *testing.T) {
 	resetState := func() {
 		db, _ := ethdb.NewMemDatabase()
 		statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
-		pool.currentState = func() (*state.StateDB, error) { return statedb, nil }
-		currentState, _ := pool.currentState()
+		pool.blockChain = &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed), new(event.Feed)}
+		currentState, _ := pool.blockChain.State()
 		currentState.AddBalance(addr, big.NewInt(100000000000000))
 		pool.lockedReset()
 	}
@@ -358,7 +387,7 @@ func TestTransactionDoubleNonce(t *testing.T) {
 	if replace, err := pool.add(tx2, false); err != nil || !replace {
 		t.Errorf("second transaction insert failed (%v) or not reported replacement (%v)", err, replace)
 	}
-	state, _ := pool.currentState()
+	state, _ := pool.blockChain.State()
 	pool.promoteExecutables(state, []common.Address{addr})
 	if pool.pending[addr].Len() != 1 {
 		t.Error("expected 1 pending transactions, got", pool.pending[addr].Len())
@@ -386,7 +415,7 @@ func TestMissingNonce(t *testing.T) {
 	defer pool.Stop()
 
 	addr := crypto.PubkeyToAddress(key.PublicKey)
-	currentState, _ := pool.currentState()
+	currentState, _ := pool.blockChain.State()
 	currentState.AddBalance(addr, big.NewInt(100000000000000))
 	tx := transaction(1, big.NewInt(100000), key)
 	if _, err := pool.add(tx, false); err != nil {
@@ -409,7 +438,7 @@ func TestNonceRecovery(t *testing.T) {
 	defer pool.Stop()
 
 	addr := crypto.PubkeyToAddress(key.PublicKey)
-	currentState, _ := pool.currentState()
+	currentState, _ := pool.blockChain.State()
 	currentState.SetNonce(addr, n)
 	currentState.AddBalance(addr, big.NewInt(100000000000000))
 	pool.lockedReset()
@@ -431,11 +460,14 @@ func TestRemovedTxEvent(t *testing.T) {
 
 	tx := transaction(0, big.NewInt(1000000), key)
 	from, _ := deriveSender(tx)
-	currentState, _ := pool.currentState()
+	currentState, _ := pool.blockChain.State()
 	currentState.AddBalance(from, big.NewInt(1000000000000))
 	pool.lockedReset()
-	pool.eventMux.Post(RemovedTransactionEvent{types.Transactions{tx}})
-	pool.eventMux.Post(ChainHeadEvent{nil})
+	blockChain, _ := pool.blockChain.(*testBlockChain)
+	blockChain.rmTxFeed.Send(RemovedTransactionEvent{types.Transactions{tx}})
+	blockChain.chainHeadFeed.Send(ChainHeadEvent{nil})
+	// wait for handling events
+	<-time.After(500 * time.Millisecond)
 	if pool.pending[from].Len() != 1 {
 		t.Error("expected 1 pending tx, got", pool.pending[from].Len())
 	}
@@ -453,7 +485,7 @@ func TestTransactionDropping(t *testing.T) {
 
 	account, _ := deriveSender(transaction(0, big.NewInt(0), key))
 
-	state, _ := pool.currentState()
+	state, _ := pool.blockChain.State()
 	state.AddBalance(account, big.NewInt(1000))
 
 	// Add some pending and some queued transactions
@@ -518,7 +550,7 @@ func TestTransactionDropping(t *testing.T) {
 		t.Errorf("total transaction mismatch: have %d, want %d", len(pool.all), 4)
 	}
 	// Reduce the block gas limit, check that invalidated transactions are dropped
-	pool.gasLimit = func() *big.Int { return big.NewInt(100) }
+	pool.blockChain.(*testBlockChain).gasLimit = big.NewInt(100)
 	pool.lockedReset()
 
 	if _, ok := pool.pending[account].txs.items[tx0.Nonce()]; !ok {
@@ -548,7 +580,7 @@ func TestTransactionPostponing(t *testing.T) {
 
 	account, _ := deriveSender(transaction(0, big.NewInt(0), key))
 
-	state, _ := pool.currentState()
+	state, _ := pool.blockChain.State()
 	state.AddBalance(account, big.NewInt(1000))
 
 	// Add a batch consecutive pending transactions for validation
@@ -624,7 +656,7 @@ func TestTransactionQueueAccountLimiting(t *testing.T) {
 
 	account, _ := deriveSender(transaction(0, big.NewInt(0), key))
 
-	state, _ := pool.currentState()
+	state, _ := pool.blockChain.State()
 	state.AddBalance(account, big.NewInt(1000000))
 	pool.lockedReset()
 
@@ -667,16 +699,17 @@ func testTransactionQueueGlobalLimiting(t *testing.T, nolocals bool) {
 	// Create the pool to test the limit enforcement with
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed), new(event.Feed)}
 
 	config := testTxPoolConfig
 	config.NoLocals = nolocals
 	config.GlobalQueue = config.AccountQueue*3 - 1 // reduce the queue limits to shorten test time (-1 to make it non divisible)
 
-	pool := NewTxPool(config, params.TestChainConfig, new(event.TypeMux), func() (*state.StateDB, error) { return statedb, nil }, func() *big.Int { return big.NewInt(1000000) })
+	pool := NewTxPool(config, params.TestChainConfig, blockchain)
 	defer pool.Stop()
 
 	// Create a number of test accounts and fund them (last one will be the local)
-	state, _ := pool.currentState()
+	state, _ := pool.blockChain.State()
 
 	keys := make([]*ecdsa.PrivateKey, 5)
 	for i := 0; i < len(keys); i++ {
@@ -757,19 +790,20 @@ func testTransactionQueueTimeLimiting(t *testing.T, nolocals bool) {
 	// Create the pool to test the non-expiration enforcement
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed), new(event.Feed)}
 
 	config := testTxPoolConfig
 	config.Lifetime = time.Second
 	config.NoLocals = nolocals
 
-	pool := NewTxPool(config, params.TestChainConfig, new(event.TypeMux), func() (*state.StateDB, error) { return statedb, nil }, func() *big.Int { return big.NewInt(1000000) })
+	pool := NewTxPool(config, params.TestChainConfig, blockchain)
 	defer pool.Stop()
 
 	// Create two test accounts to ensure remotes expire but locals do not
 	local, _ := crypto.GenerateKey()
 	remote, _ := crypto.GenerateKey()
 
-	state, _ := pool.currentState()
+	state, _ := pool.blockChain.State()
 	state.AddBalance(crypto.PubkeyToAddress(local.PublicKey), big.NewInt(1000000000))
 	state.AddBalance(crypto.PubkeyToAddress(remote.PublicKey), big.NewInt(1000000000))
 
@@ -821,7 +855,7 @@ func TestTransactionPendingLimiting(t *testing.T) {
 
 	account, _ := deriveSender(transaction(0, big.NewInt(0), key))
 
-	state, _ := pool.currentState()
+	state, _ := pool.blockChain.State()
 	state.AddBalance(account, big.NewInt(1000000))
 	pool.lockedReset()
 
@@ -853,7 +887,7 @@ func testTransactionLimitingEquivalency(t *testing.T, origin uint64) {
 	defer pool1.Stop()
 
 	account1, _ := deriveSender(transaction(0, big.NewInt(0), key1))
-	state1, _ := pool1.currentState()
+	state1, _ := pool1.blockChain.State()
 	state1.AddBalance(account1, big.NewInt(1000000))
 
 	for i := uint64(0); i < testTxPoolConfig.AccountQueue+5; i++ {
@@ -866,7 +900,7 @@ func testTransactionLimitingEquivalency(t *testing.T, origin uint64) {
 	defer pool2.Stop()
 
 	account2, _ := deriveSender(transaction(0, big.NewInt(0), key2))
-	state2, _ := pool2.currentState()
+	state2, _ := pool2.blockChain.State()
 	state2.AddBalance(account2, big.NewInt(1000000))
 
 	txns := []*types.Transaction{}
@@ -900,15 +934,16 @@ func TestTransactionPendingGlobalLimiting(t *testing.T) {
 	// Create the pool to test the limit enforcement with
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed), new(event.Feed)}
 
 	config := testTxPoolConfig
 	config.GlobalSlots = config.AccountSlots * 10
 
-	pool := NewTxPool(config, params.TestChainConfig, new(event.TypeMux), func() (*state.StateDB, error) { return statedb, nil }, func() *big.Int { return big.NewInt(1000000) })
+	pool := NewTxPool(config, params.TestChainConfig, blockchain)
 	defer pool.Stop()
 
 	// Create a number of test accounts and fund them
-	state, _ := pool.currentState()
+	state, _ := pool.blockChain.State()
 
 	keys := make([]*ecdsa.PrivateKey, 5)
 	for i := 0; i < len(keys); i++ {
@@ -946,17 +981,18 @@ func TestTransactionCapClearsFromAll(t *testing.T) {
 	// Create the pool to test the limit enforcement with
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed), new(event.Feed)}
 
 	config := testTxPoolConfig
 	config.AccountSlots = 2
 	config.AccountQueue = 2
 	config.GlobalSlots = 8
 
-	pool := NewTxPool(config, params.TestChainConfig, new(event.TypeMux), func() (*state.StateDB, error) { return statedb, nil }, func() *big.Int { return big.NewInt(1000000) })
+	pool := NewTxPool(config, params.TestChainConfig, blockchain)
 	defer pool.Stop()
 
 	// Create a number of test accounts and fund them
-	state, _ := pool.currentState()
+	state, _ := pool.blockChain.State()
 
 	key, _ := crypto.GenerateKey()
 	addr := crypto.PubkeyToAddress(key.PublicKey)
@@ -980,15 +1016,16 @@ func TestTransactionPendingMinimumAllowance(t *testing.T) {
 	// Create the pool to test the limit enforcement with
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed), new(event.Feed)}
 
 	config := testTxPoolConfig
 	config.GlobalSlots = 0
 
-	pool := NewTxPool(config, params.TestChainConfig, new(event.TypeMux), func() (*state.StateDB, error) { return statedb, nil }, func() *big.Int { return big.NewInt(1000000) })
+	pool := NewTxPool(config, params.TestChainConfig, blockchain)
 	defer pool.Stop()
 
 	// Create a number of test accounts and fund them
-	state, _ := pool.currentState()
+	state, _ := pool.blockChain.State()
 
 	keys := make([]*ecdsa.PrivateKey, 5)
 	for i := 0; i < len(keys); i++ {
@@ -1028,12 +1065,13 @@ func TestTransactionPoolRepricing(t *testing.T) {
 	// Create the pool to test the pricing enforcement with
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed), new(event.Feed)}
 
-	pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, new(event.TypeMux), func() (*state.StateDB, error) { return statedb, nil }, func() *big.Int { return big.NewInt(1000000) })
+	pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)
 	defer pool.Stop()
 
 	// Create a number of test accounts and fund them
-	state, _ := pool.currentState()
+	state, _ := pool.blockChain.State()
 
 	keys := make([]*ecdsa.PrivateKey, 3)
 	for i := 0; i < len(keys); i++ {
@@ -1112,16 +1150,17 @@ func TestTransactionPoolUnderpricing(t *testing.T) {
 	// Create the pool to test the pricing enforcement with
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed), new(event.Feed)}
 
 	config := testTxPoolConfig
 	config.GlobalSlots = 2
 	config.GlobalQueue = 2
 
-	pool := NewTxPool(config, params.TestChainConfig, new(event.TypeMux), func() (*state.StateDB, error) { return statedb, nil }, func() *big.Int { return big.NewInt(1000000) })
+	pool := NewTxPool(config, params.TestChainConfig, blockchain)
 	defer pool.Stop()
 
 	// Create a number of test accounts and fund them
-	state, _ := pool.currentState()
+	state, _ := pool.blockChain.State()
 
 	keys := make([]*ecdsa.PrivateKey, 3)
 	for i := 0; i < len(keys); i++ {
@@ -1199,14 +1238,15 @@ func TestTransactionReplacement(t *testing.T) {
 	// Create the pool to test the pricing enforcement with
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed), new(event.Feed)}
 
-	pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, new(event.TypeMux), func() (*state.StateDB, error) { return statedb, nil }, func() *big.Int { return big.NewInt(1000000) })
+	pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)
 	defer pool.Stop()
 
 	// Create a test account to add transactions with
 	key, _ := crypto.GenerateKey()
 
-	state, _ := pool.currentState()
+	state, _ := pool.blockChain.State()
 	state.AddBalance(crypto.PubkeyToAddress(key.PublicKey), big.NewInt(1000000000))
 
 	// Add pending transactions, ensuring the minimum price bump is enforced for replacement (for ultra low prices too)
@@ -1278,19 +1318,20 @@ func testTransactionJournaling(t *testing.T, nolocals bool) {
 	// Create the original pool to inject transaction into the journal
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed), new(event.Feed)}
 
 	config := testTxPoolConfig
 	config.NoLocals = nolocals
 	config.Journal = journal
 	config.Rejournal = time.Second
 
-	pool := NewTxPool(config, params.TestChainConfig, new(event.TypeMux), func() (*state.StateDB, error) { return statedb, nil }, func() *big.Int { return big.NewInt(1000000) })
+	pool := NewTxPool(config, params.TestChainConfig, blockchain)
 
 	// Create two test accounts to ensure remotes expire but locals do not
 	local, _ := crypto.GenerateKey()
 	remote, _ := crypto.GenerateKey()
 
-	statedb, _ = pool.currentState()
+	statedb, _ = pool.blockChain.State()
 	statedb.AddBalance(crypto.PubkeyToAddress(local.PublicKey), big.NewInt(1000000000))
 	statedb.AddBalance(crypto.PubkeyToAddress(remote.PublicKey), big.NewInt(1000000000))
 
@@ -1320,7 +1361,8 @@ func testTransactionJournaling(t *testing.T, nolocals bool) {
 	// Terminate the old pool, bump the local nonce, create a new pool and ensure relevant transaction survive
 	pool.Stop()
 	statedb.SetNonce(crypto.PubkeyToAddress(local.PublicKey), 1)
-	pool = NewTxPool(config, params.TestChainConfig, new(event.TypeMux), func() (*state.StateDB, error) { return statedb, nil }, func() *big.Int { return big.NewInt(1000000) })
+	blockchain = &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed), new(event.Feed)}
+	pool = NewTxPool(config, params.TestChainConfig, blockchain)
 
 	pending, queued = pool.Stats()
 	if queued != 0 {
@@ -1344,7 +1386,8 @@ func testTransactionJournaling(t *testing.T, nolocals bool) {
 	time.Sleep(2 * config.Rejournal)
 	pool.Stop()
 	statedb.SetNonce(crypto.PubkeyToAddress(local.PublicKey), 1)
-	pool = NewTxPool(config, params.TestChainConfig, new(event.TypeMux), func() (*state.StateDB, error) { return statedb, nil }, func() *big.Int { return big.NewInt(1000000) })
+	blockchain = &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed), new(event.Feed)}
+	pool = NewTxPool(config, params.TestChainConfig, blockchain)
 
 	pending, queued = pool.Stats()
 	if pending != 0 {
@@ -1377,7 +1420,7 @@ func benchmarkPendingDemotion(b *testing.B, size int) {
 	defer pool.Stop()
 
 	account, _ := deriveSender(transaction(0, big.NewInt(0), key))
-	state, _ := pool.currentState()
+	state, _ := pool.blockChain.State()
 	state.AddBalance(account, big.NewInt(1000000))
 
 	for i := 0; i < size; i++ {
@@ -1403,7 +1446,7 @@ func benchmarkFuturePromotion(b *testing.B, size int) {
 	defer pool.Stop()
 
 	account, _ := deriveSender(transaction(0, big.NewInt(0), key))
-	state, _ := pool.currentState()
+	state, _ := pool.blockChain.State()
 	state.AddBalance(account, big.NewInt(1000000))
 
 	for i := 0; i < size; i++ {
@@ -1424,7 +1467,7 @@ func BenchmarkPoolInsert(b *testing.B) {
 	defer pool.Stop()
 
 	account, _ := deriveSender(transaction(0, big.NewInt(0), key))
-	state, _ := pool.currentState()
+	state, _ := pool.blockChain.State()
 	state.AddBalance(account, big.NewInt(1000000))
 
 	txs := make(types.Transactions, b.N)
@@ -1449,7 +1492,7 @@ func benchmarkPoolBatchInsert(b *testing.B, size int) {
 	defer pool.Stop()
 
 	account, _ := deriveSender(transaction(0, big.NewInt(0), key))
-	state, _ := pool.currentState()
+	state, _ := pool.blockChain.State()
 	state.AddBalance(account, big.NewInt(1000000))
 
 	batches := make([]types.Transactions, b.N)