all: replace some cases of strings.SplitN with strings.Cut (#28446)

Author: estensen

accounts/scwallet/wallet.go

@@ -776,16 +776,16 @@ func (w *Wallet) findAccountPath(account accounts.Account) (accounts.DerivationP
 		return nil, fmt.Errorf("scheme %s does not match wallet scheme %s", account.URL.Scheme, w.Hub.scheme)
 	}
 
-	parts := strings.SplitN(account.URL.Path, "/", 2)
-	if len(parts) != 2 {
+	url, path, found := strings.Cut(account.URL.Path, "/")
+	if !found {
 		return nil, fmt.Errorf("invalid URL format: %s", account.URL)
 	}
 
-	if parts[0] != fmt.Sprintf("%x", w.PublicKey[1:3]) {
+	if url != fmt.Sprintf("%x", w.PublicKey[1:3]) {
 		return nil, fmt.Errorf("URL %s is not for this wallet", account.URL)
 	}
 
-	return accounts.ParseDerivationPath(parts[1])
+	return accounts.ParseDerivationPath(path)
 }
 
 // Session represents a secured communication session with the wallet.

cmd/p2psim/main.go

@@ -417,9 +417,7 @@ func rpcNode(ctx *cli.Context) error {
 }
 
 func rpcSubscribe(client *rpc.Client, out io.Writer, method string, args ...string) error {
-	parts := strings.SplitN(method, "_", 2)
-	namespace := parts[0]
-	method = parts[1]
+	namespace, method, _ := strings.Cut(method, "_")
 	ch := make(chan interface{})
 	subArgs := make([]interface{}, len(args)+1)
 	subArgs[0] = method

p2p/nat/nat.go

@@ -61,12 +61,12 @@ type Interface interface {
 //	"pmp:192.168.0.1"    uses NAT-PMP with the given gateway address
 func Parse(spec string) (Interface, error) {
 	var (
-		parts = strings.SplitN(spec, ":", 2)
-		mech  = strings.ToLower(parts[0])
-		ip    net.IP
+		before, after, found = strings.Cut(spec, ":")
+		mech                 = strings.ToLower(before)
+		ip                   net.IP
 	)
-	if len(parts) > 1 {
-		ip = net.ParseIP(parts[1])
+	if found {
+		ip = net.ParseIP(after)
 		if ip == nil {
 			return nil, errors.New("invalid IP address")
 		}
@@ -86,7 +86,7 @@ func Parse(spec string) (Interface, error) {
 	case "pmp", "natpmp", "nat-pmp":
 		return PMP(ip), nil
 	default:
-		return nil, fmt.Errorf("unknown mechanism %q", parts[0])
+		return nil, fmt.Errorf("unknown mechanism %q", before)
 	}
 }
 

p2p/simulations/http.go

@@ -479,12 +479,12 @@ func (s *Server) StreamNetworkEvents(w http.ResponseWriter, req *http.Request) {
 func NewMsgFilters(filterParam string) (MsgFilters, error) {
 	filters := make(MsgFilters)
 	for _, filter := range strings.Split(filterParam, "-") {
-		protoCodes := strings.SplitN(filter, ":", 2)
-		if len(protoCodes) != 2 || protoCodes[0] == "" || protoCodes[1] == "" {
+		proto, codes, found := strings.Cut(filter, ":")
+		if !found || proto == "" || codes == "" {
 			return nil, fmt.Errorf("invalid message filter: %s", filter)
 		}
-		proto := protoCodes[0]
-		for _, code := range strings.Split(protoCodes[1], ",") {
+
+		for _, code := range strings.Split(codes, ",") {
 			if code == "*" || code == "-1" {
 				filters[MsgFilter{Proto: proto, Code: -1}] = struct{}{}
 				continue

rpc/json.go

@@ -86,8 +86,8 @@ func (msg *jsonrpcMessage) isUnsubscribe() bool {
 }
 
 func (msg *jsonrpcMessage) namespace() string {
-	elem := strings.SplitN(msg.Method, serviceMethodSeparator, 2)
-	return elem[0]
+	before, _, _ := strings.Cut(msg.Method, serviceMethodSeparator)
+	return before
 }
 
 func (msg *jsonrpcMessage) String() string {

rpc/service.go

@@ -93,13 +93,13 @@ func (r *serviceRegistry) registerName(name string, rcvr interface{}) error {
 
 // callback returns the callback corresponding to the given RPC method name.
 func (r *serviceRegistry) callback(method string) *callback {
-	elem := strings.SplitN(method, serviceMethodSeparator, 2)
-	if len(elem) != 2 {
+	before, after, found := strings.Cut(method, serviceMethodSeparator)
+	if !found {
 		return nil
 	}
 	r.mu.Lock()
 	defer r.mu.Unlock()
-	return r.services[elem[0]].callbacks[elem[1]]
+	return r.services[before].callbacks[after]
 }
 
 // subscription returns a subscription callback in the given service.