Move empty host handling to the DB specific code

sqlx-core/src/io/tls.rs

@@ -4,7 +4,6 @@ use std::pin::Pin;
 use std::task::{Context, Poll};
 
 use crate::runtime::{AsyncRead, AsyncWrite, TcpStream};
-use crate::url::Url;
 
 use self::Inner::*;
 
@@ -21,8 +20,8 @@ enum Inner {
 }
 
 impl MaybeTlsStream {
-    pub async fn connect(url: &Url, default_port: u16) -> crate::Result<Self> {
-        let conn = TcpStream::connect((url.host(), url.port(default_port))).await?;
+    pub async fn connect(host: &str, port: u16) -> crate::Result<Self> {
+        let conn = TcpStream::connect((host, port)).await?;
         Ok(Self {
             inner: Inner::NotTls(conn),
         })
@@ -43,7 +42,7 @@ impl MaybeTlsStream {
     #[cfg_attr(docsrs, doc(cfg(feature = "tls")))]
     pub async fn upgrade(
         &mut self,
-        url: &Url,
+        host: &str,
         connector: async_native_tls::TlsConnector,
     ) -> crate::Result<()> {
         let conn = match std::mem::replace(&mut self.inner, Upgrading) {
@@ -52,7 +51,7 @@ impl MaybeTlsStream {
             Upgrading => return Err(tls_err!("connection already failed to upgrade").into()),
         };
 
-        self.inner = Tls(connector.connect(url.host(), conn).await?);
+        self.inner = Tls(connector.connect(host, conn).await?);
 
         Ok(())
     }

sqlx-core/src/mysql/stream.rs

@@ -34,7 +34,9 @@ pub(crate) struct MySqlStream {
 
 impl MySqlStream {
     pub(super) async fn new(url: &Url) -> crate::Result<Self> {
-        let stream = MaybeTlsStream::connect(&url, 3306).await?;
+        let host = url.host().unwrap_or("localhost");
+        let port = url.port(3306);
+        let stream = MaybeTlsStream::connect(host, port).await?;
 
         let mut capabilities = Capabilities::PROTOCOL_41
             | Capabilities::IGNORE_SPACE

sqlx-core/src/mysql/tls.rs

@@ -116,5 +116,8 @@ async fn try_upgrade(
         )
         .await?;
 
-    stream.stream.upgrade(url, connector).await
+    stream
+        .stream
+        .upgrade(url.host().unwrap_or("localhost"), connector)
+        .await
 }

sqlx-core/src/postgres/stream.rs

@@ -23,7 +23,9 @@ pub struct PgStream {
 
 impl PgStream {
     pub(super) async fn new(url: &Url) -> crate::Result<Self> {
-        let stream = MaybeTlsStream::connect(&url, 5432).await?;
+        let host = url.host().unwrap_or("localhost");
+        let port = url.port(5432);
+        let stream = MaybeTlsStream::connect(host, port).await?;
 
         Ok(Self {
             notifications: None,

sqlx-core/src/postgres/tls.rs

@@ -105,7 +105,8 @@ async fn try_upgrade(
         }
     }
 
-    stream.stream.upgrade(url, connector).await?;
+    let host = url.host().unwrap_or("localhost");
+    stream.stream.upgrade(host, connector).await?;
 
     Ok(true)
 }

sqlx-core/src/url.rs

@@ -34,13 +34,10 @@ impl Url {
         self.0.as_str()
     }
 
-    pub fn host(&self) -> &str {
-        let host = self.0.host_str();
-
-        match host {
-            Some(host) if !host.is_empty() => host,
-
-            _ => "localhost",
+    pub fn host(&self) -> Option<&str> {
+        match self.0.host_str()? {
+            "" => None,
+            host => Some(host),
         }
     }