perf: use static strings for static error messages and avoid needless clones

httpsig-hyper/examples/hyper-request.rs

@@ -48,7 +48,7 @@ async fn sender_ed25519(req: &mut Request<BoxBody>) {
 
   // set signature with custom signature name
   req
-    .set_message_signature(&signature_params, &secret_key, Some("siged25519"))
+    .set_message_signature(signature_params, &secret_key, Some("siged25519"))
     .await
     .unwrap();
 }
@@ -70,7 +70,7 @@ async fn sender_hs256(req: &mut Request<BoxBody>) {
   signature_params.set_random_nonce();
 
   req
-    .set_message_signature(&signature_params, &shared_key, Some("sighs256"))
+    .set_message_signature(signature_params, &shared_key, Some("sighs256"))
     .await
     .unwrap();
 }

httpsig-hyper/examples/hyper-response.rs

@@ -60,7 +60,7 @@ async fn sender_ed25519(res: &mut Response<BoxBody>, received_req: &Request<BoxB
 
   // set signature with custom signature name
   res
-    .set_message_signature(&signature_params, &secret_key, Some("siged25519"), Some(received_req))
+    .set_message_signature(signature_params, &secret_key, Some("siged25519"), Some(received_req))
     .await
     .unwrap();
 }
@@ -82,7 +82,7 @@ async fn sender_hs256(res: &mut Response<BoxBody>, received_req: &Request<BoxBod
   signature_params.set_random_nonce();
 
   res
-    .set_message_signature(&signature_params, &shared_key, Some("sighs256"), Some(received_req))
+    .set_message_signature(signature_params, &shared_key, Some("sighs256"), Some(received_req))
     .await
     .unwrap();
 }

httpsig-hyper/src/error.rs

@@ -1,3 +1,5 @@
+use std::borrow::Cow;
+
 use httpsig::prelude::HttpSigError;
 use thiserror::Error;
 
@@ -9,7 +11,7 @@ pub type HyperSigResult<T> = std::result::Result<T, HyperSigError>;
 pub enum HyperSigError {
   /// No signature headers found
   #[error("No signature headers found: {0}")]
-  NoSignatureHeaders(String),
+  NoSignatureHeaders(&'static str),
 
   /// Failed to parse signature headers
   #[error("Failed to stringify signature headers: {0}")]
@@ -21,15 +23,15 @@ pub enum HyperSigError {
 
   /// Invalid component name
   #[error("Invalid component name: {0}")]
-  InvalidComponentName(String),
+  InvalidComponentName(Cow<'static, str>),
 
   /// Invalid component param
   #[error("Invalid component param: {0}")]
   InvalidComponentParam(String),
 
   /// Invalid signature
   #[error("Invalid signature: {0}")]
-  InvalidSignature(String),
+  InvalidSignature(&'static str),
 
   /// Inherited from HttpSigError
   #[error("HttpSigError: {0}")]