move Mempool interface into mempool package

Refs #2659

Breaking changes in the mempool package:

- Mempool now an interface
- old Mempool renamed to CListMempool

Breaking changes to state package:

- MockMempool moved to mempool/mock package and renamed to Mempool
- Mempool interface moved to mempool package

rpc/client/rpc_test.go

@@ -249,7 +249,8 @@ func TestAppCalls(t *testing.T) {
 func TestBroadcastTxSync(t *testing.T) {
 	require := require.New(t)
 
-	mempool := node.MempoolReactor().Mempool
+	// TODO (melekes): use mempool which is set on RPC rather than getting it from node
+	mempool := node.Mempool()
 	initMempoolSize := mempool.Size()
 
 	for i, c := range GetClients() {
@@ -269,7 +270,7 @@ func TestBroadcastTxSync(t *testing.T) {
 func TestBroadcastTxCommit(t *testing.T) {
 	require := require.New(t)
 
-	mempool := node.MempoolReactor().Mempool
+	mempool := node.Mempool()
 	for i, c := range GetClients() {
 		_, _, tx := MakeTxKV()
 		bres, err := c.BroadcastTxCommit(tx)
@@ -284,7 +285,7 @@ func TestBroadcastTxCommit(t *testing.T) {
 func TestUnconfirmedTxs(t *testing.T) {
 	_, _, tx := MakeTxKV()
 
-	mempool := node.MempoolReactor().Mempool
+	mempool := node.Mempool()
 	_ = mempool.CheckTx(tx, nil)
 
 	for i, c := range GetClients() {
@@ -305,7 +306,7 @@ func TestUnconfirmedTxs(t *testing.T) {
 func TestNumUnconfirmedTxs(t *testing.T) {
 	_, _, tx := MakeTxKV()
 
-	mempool := node.MempoolReactor().Mempool
+	mempool := node.Mempool()
 	_ = mempool.CheckTx(tx, nil)
 	mempoolSize := mempool.Size()
 

rpc/core/pipe.go

@@ -49,6 +49,14 @@ type peers interface {
 	Peers() p2p.IPeerSet
 }
 
+// Mempool extends the standard Mempool interface to allow getting
+// total txs size. ReapMaxTxs is used by UnconfirmedTxs to reap N transactions.
+type Mempool interface {
+	mempl.Mempool
+	ReapMaxTxs(n int) types.Txs
+	TxsBytes() int64
+}
+
 //----------------------------------------------
 // These package level globals come with setters
 // that are expected to be called only once, on startup
@@ -72,7 +80,7 @@ var (
 	txIndexer        txindex.TxIndexer
 	consensusReactor *consensus.ConsensusReactor
 	eventBus         *types.EventBus // thread safe
-	mempool          *mempl.Mempool
+	mempool          Mempool
 
 	logger log.Logger
 
@@ -87,7 +95,7 @@ func SetBlockStore(bs sm.BlockStore) {
 	blockStore = bs
 }
 
-func SetMempool(mem *mempl.Mempool) {
+func SetMempool(mem Mempool) {
 	mempool = mem
 }