Use char-based predicates in DNS resolver

lightning/src/onion_message/dns_resolution.rs

@@ -211,9 +211,9 @@ pub struct HumanReadableName {
 impl HumanReadableName {
 	/// Constructs a new [`HumanReadableName`] from the `user` and `domain` parts. See the
 	/// struct-level documentation for more on the requirements on each.
-	pub fn new(user: &str, domain: &str) -> Result<HumanReadableName, ()> {
+	pub fn new(user: &str, domain: &str) -> Result<Self, ()> {
 		// First normalize domain and remove the optional trailing `.`
-		let domain = domain.strip_suffix(".").unwrap_or(domain);
+		let domain = domain.strip_suffix('.').unwrap_or(domain);
 		if user.len() + domain.len() + REQUIRED_EXTRA_LEN > 255 {
 			return Err(());
 		}
@@ -233,24 +233,17 @@ impl HumanReadableName {
 		let mut contents = [0; 255 - REQUIRED_EXTRA_LEN];
 		contents[..user.len()].copy_from_slice(user.as_bytes());
 		contents[user.len()..user.len() + domain.len()].copy_from_slice(domain.as_bytes());
-		Ok(HumanReadableName {
-			contents,
-			user_len: user.len() as u8,
-			domain_len: domain.len() as u8,
-		})
+		Ok(Self { contents, user_len: user.len() as u8, domain_len: domain.len() as u8 })
 	}
 
 	/// Constructs a new [`HumanReadableName`] from the standard encoding - `user`@`domain`.
 	///
 	/// If `user` includes the standard BIP 353 ₿ prefix it is automatically removed as required by
 	/// BIP 353.
-	pub fn from_encoded(encoded: &str) -> Result<HumanReadableName, ()> {
-		if let Some((user, domain)) = encoded.strip_prefix('₿').unwrap_or(encoded).split_once("@")
-		{
-			Self::new(user, domain)
-		} else {
-			Err(())
-		}
+	pub fn from_encoded(encoded: &str) -> Result<Self, ()> {
+		let encoded = encoded.strip_prefix('₿').unwrap_or(encoded);
+		let (user, domain) = encoded.split_once('@').ok_or(())?;
+		Self::new(user, domain)
 	}
 
 	/// Gets the `user` part of this Human Readable Name
@@ -438,9 +431,9 @@ impl OMNameResolver {
 		&self, msg: DNSSECProof, context: DNSResolverContext,
 	) -> Option<(Vec<(HumanReadableName, PaymentId)>, Offer)> {
 		let (completed_requests, uri) = self.handle_dnssec_proof_for_uri(msg, context)?;
-		if let Some((_onchain, params)) = uri.split_once("?") {
-			for param in params.split("&") {
-				let (k, v) = if let Some(split) = param.split_once("=") {
+		if let Some((_onchain, params)) = uri.split_once('?') {
+			for param in params.split('&') {
+				let (k, v) = if let Some(split) = param.split_once('=') {
 					split
 				} else {
 					continue;