refactor: put ipv6 bracket parsing in a single function

src/client/legacy/connect/http.rs

@@ -529,7 +529,7 @@ where
         let config = &self.config;
 
         let (host, port) = get_host_port(config, &dst)?;
-        let host = host.trim_start_matches('[').trim_end_matches(']');
+        let host = crate::client::strip_ipv6_brackets(host);
 
         // If the host is already an IP addr (v4 or v6),
         // skip resolving the dns and start connecting right away.

src/client/legacy/connect/proxy/socks/v4/mod.rs

@@ -138,11 +138,7 @@ where
             // Whilst SOCKSv4 does not support IPv6, this bracket stripping will enable an IPv6
             // destination to be correctly rejected down the line. Without it, we would end up with
             // a DNS resolution failure which would be confusing.
-            let host = host_from_uri
-                .strip_prefix('[')
-                .and_then(|s| s.strip_suffix(']'))
-                .unwrap_or(host_from_uri)
-                .to_string();
+            let host = crate::client::strip_ipv6_brackets(host_from_uri).to_string();
 
             let conn = connecting.await.map_err(SocksError::Inner)?;
             config.execute(conn, host, port).await

src/client/legacy/connect/proxy/socks/v5/mod.rs

@@ -265,11 +265,7 @@ where
 
             // Note: host() returns the host part of the URI which could be a square bracketed IPv6
             // address. We need to remove any brackets to make it a valid IP address.
-            let host = host_from_uri
-                .strip_prefix('[')
-                .and_then(|s| s.strip_suffix(']'))
-                .unwrap_or(host_from_uri)
-                .to_string();
+            let host = crate::client::strip_ipv6_brackets(host_from_uri).to_string();
 
             let conn = connecting.await.map_err(SocksError::Inner)?;
             config.execute(conn, host, port).await

src/client/mod.rs

@@ -9,3 +9,24 @@ pub mod pool;
 
 #[cfg(feature = "client-proxy")]
 pub mod proxy;
+
+#[cfg(any(feature = "client-legacy", feature = "client-proxy"))]
+fn strip_ipv6_brackets(host: &str) -> &str {
+    host.strip_prefix('[')
+        .and_then(|host| host.strip_suffix(']'))
+        .unwrap_or(host)
+}
+
+#[cfg(all(test, any(feature = "client-legacy", feature = "client-proxy")))]
+mod tests {
+    use super::strip_ipv6_brackets;
+
+    #[test]
+    fn test_strip_ipv6_brackets() {
+        assert_eq!(strip_ipv6_brackets("[::1]"), "::1");
+        assert_eq!(strip_ipv6_brackets("::1"), "::1");
+        assert_eq!(strip_ipv6_brackets("example.com"), "example.com");
+        assert_eq!(strip_ipv6_brackets("[example.com"), "[example.com");
+        assert_eq!(strip_ipv6_brackets("example.com]"), "example.com]");
+    }
+}

src/client/proxy/matcher.rs

@@ -470,12 +470,7 @@ impl NoProxy {
     pub fn contains(&self, host: &str) -> bool {
         // According to RFC3986, raw IPv6 hosts will be wrapped in []. So we need to strip those off
         // the end in order to parse correctly
-        let host = if host.starts_with('[') {
-            let x: &[_] = &['[', ']'];
-            host.trim_matches(x)
-        } else {
-            host
-        };
+        let host = crate::client::strip_ipv6_brackets(host);
         match host.parse::<IpAddr>() {
             // If we can parse an IP addr, then use it, otherwise, assume it is a domain
             Ok(ip) => self.ips.contains(ip),