global: use strings.Cut where possible

Signed-off-by: Jason A. Donenfeld <[email protected]>

Author: zx2c4

conf/parser.go

@@ -167,10 +167,7 @@ func FromWgQuick(s, name string) (*Config, error) {
 	sawPrivateKey := false
 	var peer *Peer
 	for _, line := range lines {
-		pound := strings.IndexByte(line, '#')
-		if pound >= 0 {
-			line = line[:pound]
-		}
+		line, _, _ = strings.Cut(line, "#")
 		line = strings.TrimSpace(line)
 		lineLower := strings.ToLower(line)
 		if len(line) == 0 {

elevate/doas.go

@@ -19,11 +19,11 @@ import (
 func setAllEnv(env []string) {
 	windows.Clearenv()
 	for _, e := range env {
-		kv := strings.SplitN(e, "=", 2)
-		if len(kv) != 2 {
+		k, v, ok := strings.Cut(e, "=")
+		if !ok {
 			continue
 		}
-		windows.Setenv(kv[0], kv[1])
+		windows.Setenv(k, v)
 	}
 }
 

tunnel/winipcfg/winipcfg_test.go

@@ -64,7 +64,7 @@ func getTestInterface() (*IPAdapterAddresses, error) {
 
 	marker := strings.ToLower(testInterfaceMarker)
 	for _, ifc := range ifcs {
-		if strings.Index(strings.ToLower(ifc.FriendlyName()), marker) != -1 {
+		if strings.Contains(strings.ToLower(ifc.FriendlyName()), marker) {
 			return ifc, nil
 		}
 	}

updater/signify.go

@@ -53,17 +53,17 @@ func readFileList(input []byte) (fileList, error) {
 		if len(line) == 0 && index == len(fileLines)-1 {
 			break
 		}
-		components := strings.SplitN(line, "  ", 2)
-		if len(components) != 2 {
+		first, second, ok := strings.Cut(line, "  ")
+		if !ok {
 			return nil, errors.New("File hash line has too few components")
 		}
-		maybeHash, err := hex.DecodeString(components[0])
+		maybeHash, err := hex.DecodeString(first)
 		if err != nil || len(maybeHash) != blake2b.Size256 {
 			return nil, errors.New("File hash is invalid base64 or incorrect number of bytes")
 		}
 		var hash [blake2b.Size256]byte
 		copy(hash[:], maybeHash)
-		fileHashes[components[1]] = hash
+		fileHashes[second] = hash
 	}
 	if len(fileHashes) == 0 {
 		return nil, errors.New("No file hashes found in signed input")