feat!: Error for SetterResult

This implements `std::error::Error` for a newly
introduced error type. We cannot implement that
trait on `()` in this crate, so cannot offer
consumers convenient error handling via `?` etc.
(`anyhow`, ...) without a dedicated error type we
own.

Author: alexpovel

README.md

@@ -12,7 +12,7 @@ Here is an example illustrating a common usage:
 
 ```Rust
 use ada_url::Url;
-fn main() -> Result<(), ()> {
+fn main() -> Result<(), Box<dyn std::error::Error>> {
     let mut u = Url::parse("http://www.google:8080/love#drug", None).expect("bad url");
     println!("port: {:?}", u.port());
     println!("hash: {:?}", u.hash());

src/lib.rs

@@ -179,14 +179,19 @@ impl From<*mut ffi::ada_url> for Url {
     }
 }
 
-type SetterResult = Result<(), ()>;
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Default, Display)]
+pub struct SetterError;
+
+impl std::error::Error for SetterError {}
+
+type SetterResult = Result<(), SetterError>;
 
 #[inline]
 fn setter_result(successful: bool) -> SetterResult {
     if successful {
         Ok(())
     } else {
-        Err(())
+        Err(SetterError)
     }
 }
 
@@ -290,7 +295,6 @@ impl Url {
     /// url.set_href("https://lemire.me").unwrap();
     /// assert_eq!(url.href(), "https://lemire.me/");
     /// ```
-    #[allow(clippy::result_unit_err)]
     pub fn set_href(&mut self, input: &str) -> SetterResult {
         setter_result(unsafe { ffi::ada_set_href(self.0, input.as_ptr().cast(), input.len()) })
     }
@@ -318,7 +322,6 @@ impl Url {
     /// url.set_username(Some("username")).unwrap();
     /// assert_eq!(url.href(), "https://[email protected]/");
     /// ```
-    #[allow(clippy::result_unit_err)]
     pub fn set_username(&mut self, input: Option<&str>) -> SetterResult {
         setter_result(unsafe {
             ffi::ada_set_username(
@@ -352,7 +355,6 @@ impl Url {
     /// url.set_password(Some("password")).unwrap();
     /// assert_eq!(url.href(), "https://:[email protected]/");
     /// ```
-    #[allow(clippy::result_unit_err)]
     pub fn set_password(&mut self, input: Option<&str>) -> SetterResult {
         setter_result(unsafe {
             ffi::ada_set_password(
@@ -389,7 +391,6 @@ impl Url {
     /// url.set_port(Some("8080")).unwrap();
     /// assert_eq!(url.href(), "https://yagiz.co:8080/");
     /// ```
-    #[allow(clippy::result_unit_err)]
     pub fn set_port(&mut self, input: Option<&str>) -> SetterResult {
         match input {
             Some(value) => setter_result(unsafe {
@@ -462,7 +463,6 @@ impl Url {
     /// url.set_host(Some("localhost:3000")).unwrap();
     /// assert_eq!(url.href(), "https://localhost:3000/");
     /// ```
-    #[allow(clippy::result_unit_err)]
     pub fn set_host(&mut self, input: Option<&str>) -> SetterResult {
         setter_result(unsafe {
             ffi::ada_set_host(
@@ -500,7 +500,6 @@ impl Url {
     /// url.set_hostname(Some("localhost")).unwrap();
     /// assert_eq!(url.href(), "https://localhost/");
     /// ```
-    #[allow(clippy::result_unit_err)]
     pub fn set_hostname(&mut self, input: Option<&str>) -> SetterResult {
         setter_result(unsafe {
             ffi::ada_set_hostname(
@@ -534,7 +533,6 @@ impl Url {
     /// url.set_pathname(Some("/contact")).unwrap();
     /// assert_eq!(url.href(), "https://yagiz.co/contact");
     /// ```
-    #[allow(clippy::result_unit_err)]
     pub fn set_pathname(&mut self, input: Option<&str>) -> SetterResult {
         setter_result(unsafe {
             ffi::ada_set_pathname(
@@ -603,7 +601,6 @@ impl Url {
     /// url.set_protocol("http").unwrap();
     /// assert_eq!(url.href(), "http://yagiz.co/");
     /// ```
-    #[allow(clippy::result_unit_err)]
     pub fn set_protocol(&mut self, input: &str) -> SetterResult {
         setter_result(unsafe { ffi::ada_set_protocol(self.0, input.as_ptr().cast(), input.len()) })
     }