fix: use pool for all sha256 hash operations

waku/persistence/db_key.go

@@ -1,9 +1,10 @@
 package persistence
 
 import (
-	"crypto/sha256"
 	"encoding/binary"
 	"errors"
+
+	"github.com/waku-org/go-waku/waku/v2/utils"
 )
 
 const (
@@ -34,7 +35,7 @@ func (k *DBKey) Bytes() []byte {
 
 // NewDBKey creates a new DBKey with the given values.
 func NewDBKey(senderTimestamp uint64, receiverTimestamp uint64, pubsubTopic string, digest []byte) *DBKey {
-	pubSubHash := sha256.Sum256([]byte(pubsubTopic))
+	pubSubHash := utils.SHA256([]byte(pubsubTopic))
 
 	var k DBKey
 	k.raw = make([]byte, DBKeyLength)

waku/v2/protocol/envelope.go

@@ -1,10 +1,9 @@
 package protocol
 
 import (
-	"crypto/sha256"
-
 	wpb "github.com/waku-org/go-waku/waku/v2/protocol/pb"
 	"github.com/waku-org/go-waku/waku/v2/protocol/store/pb"
+	"github.com/waku-org/go-waku/waku/v2/utils"
 )
 
 // Envelope contains information about the pubsub topic of a WakuMessage
@@ -22,7 +21,7 @@ type Envelope struct {
 // as well as generating a hash based on the bytes that compose the message
 func NewEnvelope(msg *wpb.WakuMessage, receiverTime int64, pubSubTopic string) *Envelope {
 	messageHash, dataLen, _ := msg.Hash()
-	hash := sha256.Sum256(append([]byte(msg.ContentTopic), msg.Payload...))
+	hash := utils.SHA256(append([]byte(msg.ContentTopic), msg.Payload...))
 	return &Envelope{
 		msg:  msg,
 		size: dataLen,

waku/v2/protocol/relay/waku_relay.go

@@ -2,11 +2,9 @@ package relay
 
 import (
 	"context"
-	"crypto/sha256"
 	"encoding/hex"
 	"errors"
 	"fmt"
-	"hash"
 	"sync"
 
 	"github.com/libp2p/go-libp2p/core/host"
@@ -24,6 +22,7 @@ import (
 	waku_proto "github.com/waku-org/go-waku/waku/v2/protocol"
 	"github.com/waku-org/go-waku/waku/v2/protocol/pb"
 	"github.com/waku-org/go-waku/waku/v2/timesource"
+	"github.com/waku-org/go-waku/waku/v2/utils"
 )
 
 const WakuRelayID_v200 = protocol.ID("/vac/waku/relay/2.0.0")
@@ -52,22 +51,8 @@ type WakuRelay struct {
 	subscriptionsMutex sync.Mutex
 }
 
-var sha256Pool = sync.Pool{New: func() interface{} {
-	return sha256.New()
-}}
-
 func msgIdFn(pmsg *pubsub_pb.Message) string {
-	h, ok := sha256Pool.Get().(hash.Hash)
-	if !ok {
-		h = sha256.New()
-	}
-	defer sha256Pool.Put(h)
-	h.Reset()
-
-	var result [32]byte
-	h.Write(pmsg.Data)
-	h.Sum(result[:0])
-	return string(result[:])
+	return string(utils.SHA256(pmsg.Data))
 }
 
 // NewWakuRelay returns a new instance of a WakuRelay struct

waku/v2/utils/hash.go

@@ -0,0 +1,25 @@
+package utils
+
+import (
+	"crypto/sha256"
+	"hash"
+	"sync"
+)
+
+var sha256Pool = sync.Pool{New: func() interface{} {
+	return sha256.New()
+}}
+
+func SHA256(data []byte) []byte {
+	h, ok := sha256Pool.Get().(hash.Hash)
+	if !ok {
+		h = sha256.New()
+	}
+	defer sha256Pool.Put(h)
+	h.Reset()
+
+	var result [32]byte
+	h.Write(data)
+	h.Sum(result[:0])
+	return result[:]
+}