Auto merge of #73007 - yoshuawuyts:socketaddr-from-string-u16, r=sfackler

bors · bors · commit dcd470fe1be0 · 2020-06-23T00:13:50.000Z
impl ToSocketAddrs for (String, u16)

This adds a convenience impl of `ToSocketAddrs for (String, u16)`. When authoring HTTP services it's common to take command line options for `host` and `port` and parse them into `String` and `u16` respectively. Consider the following program:
```rust
#[derive(Debug, StructOpt)]
struct Config {
    host: String,
    port: u16,
}

async fn main() -&gt; io::Result&lt;()&gt; {
    let config = Config::from_args();
    let stream = TcpStream::connect((&amp;*config.host, config.port))?; // &amp;* is not ideal
    // ...
}
```

Networking is a pretty common starting point for people new to Rust, and seeing `&amp;*` in basic examples can be confusing. Even as someone that has experience with networking in Rust I tend to forget that `String` can't be passed directly there. Instead with this patch we can omit the `&amp;*` conversion and pass `host` directly:
```rust
#[derive(Debug, StructOpt)]
struct Config {
    host: String,
    port: u16,
}

async fn main() -&gt; io::Result&lt;()&gt; {
    let config = Config::from_args();
    let stream = TcpStream::connect((config.host, config.port))?; // no more conversions!
    // ...
}
```

I think should be an easy and small ergonomics improvement for networking. Thanks!
diff --git a/src/libstd/net/addr.rs b/src/libstd/net/addr.rs
@@ -964,6 +964,14 @@ impl ToSocketAddrs for (&str, u16) {
     }
 }
 
+#[stable(feature = "string_u16_to_socket_addrs", since = "1.46.0")]
+impl ToSocketAddrs for (String, u16) {
+    type Iter = vec::IntoIter<SocketAddr>;
+    fn to_socket_addrs(&self) -> io::Result<vec::IntoIter<SocketAddr>> {
+        (&*self.0, self.1).to_socket_addrs()
+    }
+}
+
 // accepts strings like 'localhost:12345'
 #[stable(feature = "rust1", since = "1.0.0")]
 impl ToSocketAddrs for str {

Original file line number	Diff line number	Diff line change
`@@ -964,6 +964,14 @@ impl ToSocketAddrs for (&str, u16) {`
`964`	`964`	`}`
`965`	`965`	`}`
`966`	`966`
	`967`	`+#[stable(feature = "string_u16_to_socket_addrs", since = "1.46.0")]`
	`968`	`+impl ToSocketAddrs for (String, u16) {`
	`969`	`+ type Iter = vec::IntoIter<SocketAddr>;`
	`970`	`+ fn to_socket_addrs(&self) -> io::Result<vec::IntoIter<SocketAddr>> {`
	`971`	`+ (&*self.0, self.1).to_socket_addrs()`
	`972`	`+ }`
	`973`	`+}`
	`974`	`+`
`967`	`975`	`// accepts strings like 'localhost:12345'`
`968`	`976`	`#[stable(feature = "rust1", since = "1.0.0")]`
`969`	`977`	`impl ToSocketAddrs for str {`