further fixes after review

testscommon/evictionNotifierStub.go

@@ -0,0 +1,18 @@
+package testscommon
+
+// EvictionNotifierStub -
+type EvictionNotifierStub struct {
+	NotifyEvictionCalled func(txHash []byte)
+}
+
+// NotifyEviction -
+func (stub *EvictionNotifierStub) NotifyEviction(txHash []byte) {
+	if stub.NotifyEvictionCalled != nil {
+		stub.NotifyEvictionCalled(txHash)
+	}
+}
+
+// IsInterfaceNil -
+func (stub *EvictionNotifierStub) IsInterfaceNil() bool {
+	return stub == nil
+}

txcache/baseTxCache.go

@@ -3,7 +3,9 @@ package txcache
 import (
 	"sync"
 
+	"github.com/multiversx/mx-chain-core-go/core/check"
 	"github.com/multiversx/mx-chain-storage-go/common"
+	"github.com/multiversx/mx-chain-storage-go/types"
 )
 
 const maxNumOfEvictionWorkers = 5
@@ -15,13 +17,13 @@ type evictionWorkerPool interface {
 
 type baseTxCache struct {
 	mutEvictionHandlers sync.RWMutex
-	evictionHandlers    []func(txHash []byte)
+	evictionHandlers    []types.EvictionNotifier
 	evictionWorkerPool  evictionWorkerPool
 }
 
 // RegisterEvictionHandler registers a handler which will be called when a tx is evicted from cache
-func (cache *baseTxCache) RegisterEvictionHandler(handler func(hash []byte)) error {
-	if handler == nil {
+func (cache *baseTxCache) RegisterEvictionHandler(handler types.EvictionNotifier) error {
+	if check.IfNil(handler) {
 		return common.ErrNilEvictionHandler
 	}
 
@@ -35,12 +37,13 @@ func (cache *baseTxCache) RegisterEvictionHandler(handler func(hash []byte)) err
 // notifyEvictionHandlers will be called on a separate go routine
 func (cache *baseTxCache) notifyEvictionHandlers(txHashes [][]byte) {
 	cache.mutEvictionHandlers.RLock()
-	handlers := cache.evictionHandlers
+	handlers := make([]types.EvictionNotifier, len(cache.evictionHandlers))
+	copy(handlers, cache.evictionHandlers)
 	cache.mutEvictionHandlers.RUnlock()
 
 	for _, handler := range handlers {
 		for _, txHash := range txHashes {
-			handler(txHash)
+			handler.NotifyEviction(txHash)
 		}
 	}
 }

txcache/crossTxCache.go

@@ -40,7 +40,7 @@ func NewCrossTxCache(config ConfigDestinationMe) (*CrossTxCache, error) {
 	cache := CrossTxCache{
 		ImmunityCache: immunityCache,
 		baseTxCache: &baseTxCache{
-			evictionHandlers:   make([]func(txHash []byte), 0),
+			evictionHandlers:   make([]types.EvictionNotifier, 0),
 			evictionWorkerPool: workerpool.New(maxNumOfEvictionWorkers),
 		},
 		config: config,

txcache/crossTxCache_test.go

@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"github.com/multiversx/mx-chain-storage-go/common"
+	"github.com/multiversx/mx-chain-storage-go/testscommon"
 	"github.com/stretchr/testify/require"
 )
 
@@ -74,9 +75,11 @@ func TestCrossTxCache_RegisterEvictionHandler(t *testing.T) {
 	require.Equal(t, common.ErrNilEvictionHandler, err)
 
 	ch := make(chan struct{})
-	err = cache.RegisterEvictionHandler(func(hash []byte) {
-		require.True(t, bytes.Equal([]byte("hash-1"), hash))
-		ch <- struct{}{}
+	err = cache.RegisterEvictionHandler(&testscommon.EvictionNotifierStub{
+		NotifyEvictionCalled: func(hash []byte) {
+			require.True(t, bytes.Equal([]byte("hash-1"), hash))
+			ch <- struct{}{}
+		},
 	})
 	require.NoError(t, err)
 

txcache/txCache.go

@@ -53,7 +53,7 @@ func NewTxCache(config ConfigSourceMe, txGasHandler TxGasHandler) (*TxCache, err
 	scoreComputerObj := newDefaultScoreComputer(txFeeHelper)
 	txCache := &TxCache{
 		baseTxCache: &baseTxCache{
-			evictionHandlers:   make([]func(txHash []byte), 0),
+			evictionHandlers:   make([]types.EvictionNotifier, 0),
 			evictionWorkerPool: workerpool.New(maxNumOfEvictionWorkers),
 		},
 		name:            config.Name,

txcache/txCache_test.go

@@ -14,6 +14,7 @@ import (
 	"github.com/multiversx/mx-chain-core-go/core"
 	"github.com/multiversx/mx-chain-core-go/core/check"
 	"github.com/multiversx/mx-chain-storage-go/common"
+	"github.com/multiversx/mx-chain-storage-go/testscommon"
 	"github.com/multiversx/mx-chain-storage-go/types"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -553,9 +554,11 @@ func TestTxCache_NoCriticalInconsistency_WhenConcurrentAdditionsAndRemovals(t *t
 
 	handlerCalls := uint32(0)
 	evictionHandlerWG := sync.WaitGroup{}
-	_ = cache.RegisterEvictionHandler(func(hash []byte) {
-		atomic.AddUint32(&handlerCalls, 1)
-		evictionHandlerWG.Done()
+	_ = cache.RegisterEvictionHandler(&testscommon.EvictionNotifierStub{
+		NotifyEvictionCalled: func(hash []byte) {
+			atomic.AddUint32(&handlerCalls, 1)
+			evictionHandlerWG.Done()
+		},
 	})
 
 	// A lot of routines concur to add & remove THE FIRST transaction of a sender
@@ -659,10 +662,12 @@ func TestTxCache_RegisterEvictionHandler(t *testing.T) {
 
 	ch := make(chan uint32)
 	cnt := uint32(0)
-	err = cache.RegisterEvictionHandler(func(hash []byte) {
-		atomic.AddUint32(&cnt, 1)
-		require.True(t, bytes.Equal([]byte("hash-1"), hash) || bytes.Equal([]byte("hash-2"), hash))
-		ch <- atomic.LoadUint32(&cnt)
+	err = cache.RegisterEvictionHandler(&testscommon.EvictionNotifierStub{
+		NotifyEvictionCalled: func(hash []byte) {
+			atomic.AddUint32(&cnt, 1)
+			require.True(t, bytes.Equal([]byte("hash-1"), hash) || bytes.Equal([]byte("hash-2"), hash))
+			ch <- atomic.LoadUint32(&cnt)
+		},
 	})
 	require.NoError(t, err)
 

types/interface.go

@@ -225,8 +225,14 @@ type ShardIDProvider interface {
 	IsInterfaceNil() bool
 }
 
-// PersisterCreator defines the behavour of a component which is able to create a persister
+// PersisterCreator defines the behaviour of a component which is able to create a persister
 type PersisterCreator interface {
 	CreateBasePersister(path string) (Persister, error)
 	IsInterfaceNil() bool
 }
+
+// EvictionNotifier defines the behaviour of a component which is able to handle an evicted transaction
+type EvictionNotifier interface {
+	NotifyEviction(txHash []byte)
+	IsInterfaceNil() bool
+}