whisper: minor refactoring

cmd/wnode/main.go

@@ -308,7 +308,11 @@ func configureNode() {
 	if *asymmetricMode {
 		if len(*argPub) == 0 {
 			s := scanLine("Please enter the peer's public key: ")
-			pub = crypto.ToECDSAPub(common.FromHex(s))
+			b := common.FromHex(s)
+			if b == nil {
+				utils.Fatalf("Error: can not convert hexadecimal string")
+			}
+			pub = crypto.ToECDSAPub(b)
 			if !isKeyValid(pub) {
 				utils.Fatalf("Error: invalid public key")
 			}

whisper/whisperv5/api.go

@@ -214,7 +214,6 @@ func (api *PublicWhisperAPI) Subscribe(args WhisperFilterArgs) (string, error) {
 	}
 
 	filter := Filter{
-		Src:      crypto.ToECDSAPub(common.FromHex(args.SignedWith)),
 		PoW:      args.MinPoW,
 		Messages: make(map[common.Hash]*ReceivedMessage),
 		AllowP2P: args.AllowP2P,
@@ -233,6 +232,11 @@ func (api *PublicWhisperAPI) Subscribe(args WhisperFilterArgs) (string, error) {
 	}
 
 	if len(args.SignedWith) > 0 {
+		sb := common.FromHex(args.SignedWith)
+		if sb == nil {
+			return "", errors.New("subscribe: SignedWith parameter is invalid")
+		}
+		filter.Src = crypto.ToECDSAPub(sb)
 		if !ValidatePublicKey(filter.Src) {
 			return "", errors.New("subscribe: invalid 'SignedWith' field")
 		}
@@ -346,7 +350,11 @@ func (api *PublicWhisperAPI) Post(args PostArgs) error {
 			return errors.New("post: topic is missing for symmetric encryption")
 		}
 	} else if args.Type == "asym" {
-		params.Dst = crypto.ToECDSAPub(common.FromHex(args.Key))
+		kb := common.FromHex(args.Key)
+		if kb == nil {
+			return errors.New("post: public key for asymmetric encryption is invalid")
+		}
+		params.Dst = crypto.ToECDSAPub(kb)
 		if !ValidatePublicKey(params.Dst) {
 			return errors.New("post: public key for asymmetric encryption is invalid")
 		}

whisper/whisperv5/message.go

@@ -100,35 +100,21 @@ func NewSentMessage(params *MessageParams) (*SentMessage, error) {
 }
 
 // getSizeOfLength returns the number of bytes necessary to encode the entire size padding (including these bytes)
-func getSizeOfLength(b []byte) (int, error) {
-	// prefer clarity over efficiency
-	var sizeOfLength int
-	len := len(b)
-
-	// first iteration
-	if len < 256 {
-		sizeOfLength = 1
-	} else if len < 256*256 {
-		sizeOfLength = 2
-	} else if len < 256*256*256 {
-		sizeOfLength = 3
-	} else {
-		return 0, errors.New("oversized padding parameter")
+func getSizeOfLength(b []byte) (sz int, err error) {
+	sz = intSize(len(b))      // first iteration
+	sz = intSize(len(b) + sz) // second iteration
+	if sz > 3 {
+		err = errors.New("oversized padding parameter")
+	}
+	return sz, err
 }
 
-	// second iteration
-	total := len + sizeOfLength
-	if total < 256 {
-		sizeOfLength = 1
-	} else if total < 256*256 {
-		sizeOfLength = 2
-	} else if total < 256*256*256 {
-		sizeOfLength = 3
-	} else {
-		return 0, errors.New("oversized padding parameter")
+// sizeOfIntSize returns minimal number of bytes necessary to encode an integer value
+func intSize(i int) (s int) {
+	for s = 1; i >= 256; s++ {
+		i /= 256
 	}
-
-	return sizeOfLength, nil
+	return s
 }
 
 // appendPadding appends the pseudorandom padding bytes and sets the padding flag.

whisper/whisperv5/peer.go

@@ -162,7 +162,9 @@ func (p *Peer) broadcast() error {
 			}
 		}
 	}
+	if cnt > 0 {
 		log.Trace("broadcast", "num. messages", cnt)
+	}
 	return nil
 }