Merge fe808ab94e into 96f564672a

src/net/addr.rs

@@ -1,28 +1,13 @@
+use std::future;
 use std::future::Future;
-use std::mem;
 use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
 use std::net::{SocketAddr, SocketAddrV4, SocketAddrV6};
 use std::pin::Pin;
 
 use crate::io;
-use crate::task::{spawn_blocking, Context, JoinHandle, Poll};
+use crate::task::{spawn_blocking};
 use crate::utils::Context as ErrorContext;
 
-cfg_not_docs! {
-    macro_rules! ret {
-        (impl Future<Output = $out:ty>, $fut:ty) => ($fut);
-    }
-}
-
-cfg_docs! {
-    #[doc(hidden)]
-    pub struct ImplFuture<T>(std::marker::PhantomData<T>);
-
-    macro_rules! ret {
-        (impl Future<Output = $out:ty>, $fut:ty) => (ImplFuture<$out>);
-    }
-}
-
 /// Converts or resolves addresses to [`SocketAddr`] values.
 ///
 /// This trait is an async version of [`std::net::ToSocketAddrs`].
@@ -52,114 +37,51 @@ pub trait ToSocketAddrs {
     /// resolution performed.
     ///
     /// Note that this function may block a backend thread while resolution is performed.
-    fn to_socket_addrs(
+    fn to_socket_addrs<'a>(
-        &self,
+        &'a self,
-    ) -> ret!(
+    ) -> Pin<Box<dyn Future<Output = io::Result<Self::Iter>> + 'a + Send>>;
-        impl Future<Output = Self::Iter>,
-        ToSocketAddrsFuture<Self::Iter>
-    );
-}
-
-#[doc(hidden)]
-#[allow(missing_debug_implementations)]
-pub enum ToSocketAddrsFuture<I> {
-    Resolving(JoinHandle<io::Result<I>>),
-    Ready(io::Result<I>),
-    Done,
-}
-
-// The field of `Self::Resolving` is `Unpin`, and the field of `Self::Ready` is never pinned.
-impl<I> Unpin for ToSocketAddrsFuture<I> {}
-
-/// Wrap `std::io::Error` with additional message
-///
-/// Keeps the original error kind and stores the original I/O error as `source`.
-impl<T> ErrorContext for ToSocketAddrsFuture<T> {
-    fn context(self, message: impl Fn() -> String) -> Self {
-        match self {
-            ToSocketAddrsFuture::Ready(res) => ToSocketAddrsFuture::Ready(res.context(message)),
-            x => x,
-        }
-    }
-}
-
-impl<I: Iterator<Item = SocketAddr>> Future for ToSocketAddrsFuture<I> {
-    type Output = io::Result<I>;
-
-    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
-        let this = self.get_mut();
-        let state = mem::replace(this, ToSocketAddrsFuture::Done);
-
-        match state {
-            ToSocketAddrsFuture::Resolving(mut task) => {
-                let poll = Pin::new(&mut task).poll(cx);
-                if poll.is_pending() {
-                    *this = ToSocketAddrsFuture::Resolving(task);
-                }
-                poll
-            }
-            ToSocketAddrsFuture::Ready(res) => Poll::Ready(res),
-            ToSocketAddrsFuture::Done => panic!("polled a completed future"),
-        }
-    }
 }
 
 impl ToSocketAddrs for SocketAddr {
     type Iter = std::option::IntoIter<SocketAddr>;
 
-    fn to_socket_addrs(
+    fn to_socket_addrs<'a>(
-        &self,
+        &'a self,
-    ) -> ret!(
+    ) -> Pin<Box<dyn Future<Output = io::Result<Self::Iter>> + 'a + Send>> {
-        impl Future<Output = Self::Iter>,
+        Box::pin(future::ready(Ok(Some(*self).into_iter())))
-        ToSocketAddrsFuture<Self::Iter>
-    ) {
-        ToSocketAddrsFuture::Ready(Ok(Some(*self).into_iter()))
     }
 }
 
 impl ToSocketAddrs for SocketAddrV4 {
     type Iter = std::option::IntoIter<SocketAddr>;
 
-    fn to_socket_addrs(
+    fn to_socket_addrs<'a>(
-        &self,
+        &'a self,
-    ) -> ret!(
+    ) -> Pin<Box<dyn Future<Output = io::Result<Self::Iter>> + 'a + Send>> {
-        impl Future<Output = Self::Iter>,
+        Box::pin(future::ready(Ok(Some(SocketAddr::V4(*self)).into_iter())))
-        ToSocketAddrsFuture<Self::Iter>
-    ) {
-        SocketAddr::V4(*self)
-            .to_socket_addrs()
-            .context(|| format!("could not resolve address `{}`", self))
     }
 }
 
 impl ToSocketAddrs for SocketAddrV6 {
     type Iter = std::option::IntoIter<SocketAddr>;
 
-    fn to_socket_addrs(
+    fn to_socket_addrs<'a>(
-        &self,
+        &'a self,
-    ) -> ret!(
+    ) -> Pin<Box<dyn Future<Output = io::Result<Self::Iter>> + 'a + Send>> {
-        impl Future<Output = Self::Iter>,
+        Box::pin(future::ready(Ok(Some(SocketAddr::V6(*self)).into_iter())))
-        ToSocketAddrsFuture<Self::Iter>
-    ) {
-        SocketAddr::V6(*self)
-            .to_socket_addrs()
-            .context(|| format!("could not resolve address `{}`", self))
     }
 }
 
 impl ToSocketAddrs for (IpAddr, u16) {
     type Iter = std::option::IntoIter<SocketAddr>;
 
-    fn to_socket_addrs(
+    fn to_socket_addrs<'a>(
-        &self,
+        &'a self,
-    ) -> ret!(
+    ) -> Pin<Box<dyn Future<Output = io::Result<Self::Iter>> + 'a + Send>> {
-        impl Future<Output = Self::Iter>,
-        ToSocketAddrsFuture<Self::Iter>
-    ) {
         let (ip, port) = *self;
         match ip {
-            IpAddr::V4(a) => (a, port).to_socket_addrs(),
+            IpAddr::V4(a) => Box::pin(future::ready(Ok(Some(SocketAddr::V4(SocketAddrV4::new(a, port))).into_iter()))),
-            IpAddr::V6(a) => (a, port).to_socket_addrs(),
+            IpAddr::V6(a) => Box::pin(future::ready(Ok(Some(SocketAddr::V6(SocketAddrV6::new(a, port, 0, 0))).into_iter()))),
         }
     }
 }
@@ -167,50 +89,41 @@ impl ToSocketAddrs for (IpAddr, u16) {
 impl ToSocketAddrs for (Ipv4Addr, u16) {
     type Iter = std::option::IntoIter<SocketAddr>;
 
-    fn to_socket_addrs(
+    fn to_socket_addrs<'a>(
-        &self,
+        &'a self,
-    ) -> ret!(
+    ) -> Pin<Box<dyn Future<Output = io::Result<Self::Iter>> + 'a + Send>> {
-        impl Future<Output = Self::Iter>,
-        ToSocketAddrsFuture<Self::Iter>
-    ) {
         let (ip, port) = *self;
-        SocketAddrV4::new(ip, port).to_socket_addrs()
+        Box::pin(future::ready(Ok(Some(SocketAddr::V4(SocketAddrV4::new(ip, port))).into_iter())))
     }
 }
 
 impl ToSocketAddrs for (Ipv6Addr, u16) {
     type Iter = std::option::IntoIter<SocketAddr>;
 
-    fn to_socket_addrs(
+    fn to_socket_addrs<'a>(
-        &self,
+        &'a self,
-    ) -> ret!(
+    ) -> Pin<Box<dyn Future<Output = io::Result<Self::Iter>> + 'a + Send>> {
-        impl Future<Output = Self::Iter>,
-        ToSocketAddrsFuture<Self::Iter>
-    ) {
         let (ip, port) = *self;
-        SocketAddrV6::new(ip, port, 0, 0).to_socket_addrs()
+        Box::pin(future::ready(Ok(Some(SocketAddr::V6(SocketAddrV6::new(ip, port, 0, 0))).into_iter())))
     }
 }
 
 impl ToSocketAddrs for (&str, u16) {
     type Iter = std::vec::IntoIter<SocketAddr>;
 
-    fn to_socket_addrs(
+    fn to_socket_addrs<'a>(
-        &self,
+        &'a self,
-    ) -> ret!(
+    ) -> Pin<Box<dyn Future<Output = io::Result<Self::Iter>> + 'a + Send>> {
-        impl Future<Output = Self::Iter>,
-        ToSocketAddrsFuture<Self::Iter>
-    ) {
         let (host, port) = *self;
 
         if let Ok(addr) = host.parse::<Ipv4Addr>() {
             let addr = SocketAddrV4::new(addr, port);
-            return ToSocketAddrsFuture::Ready(Ok(vec![SocketAddr::V4(addr)].into_iter()));
+            return Box::pin(future::ready(Ok(vec![SocketAddr::V4(addr)].into_iter())));
         }
 
         if let Ok(addr) = host.parse::<Ipv6Addr>() {
             let addr = SocketAddrV6::new(addr, port, 0, 0);
-            return ToSocketAddrsFuture::Ready(Ok(vec![SocketAddr::V6(addr)].into_iter()));
+            return Box::pin(future::ready(Ok(vec![SocketAddr::V6(addr)].into_iter())));
         }
 
         let host = host.to_string();
@@ -219,21 +132,19 @@ impl ToSocketAddrs for (&str, u16) {
             std::net::ToSocketAddrs::to_socket_addrs(&addr)
                 .context(|| format!("could not resolve address `{:?}`", addr))
         });
-        ToSocketAddrsFuture::Resolving(task)
+
+        Box::pin(task)
     }
 }
 
 impl ToSocketAddrs for str {
     type Iter = std::vec::IntoIter<SocketAddr>;
 
-    fn to_socket_addrs(
+    fn to_socket_addrs<'a>(
-        &self,
+        &'a self,
-    ) -> ret!(
+    ) -> Pin<Box<dyn Future<Output = io::Result<Self::Iter>> + 'a + Send>> {
-        impl Future<Output = Self::Iter>,
-        ToSocketAddrsFuture<Self::Iter>
-    ) {
         if let Ok(addr) = self.parse() {
-            return ToSocketAddrsFuture::Ready(Ok(vec![addr].into_iter()));
+            return Box::pin(future::ready(Ok(vec![addr].into_iter())));
         }
 
         let addr = self.to_string();
@@ -241,32 +152,27 @@ impl ToSocketAddrs for str {
             std::net::ToSocketAddrs::to_socket_addrs(addr.as_str())
                 .context(|| format!("could not resolve address `{:?}`", addr))
         });
-        ToSocketAddrsFuture::Resolving(task)
+        
+        Box::pin(task)
     }
 }
 
-impl<'a> ToSocketAddrs for &'a [SocketAddr] {
+impl<'b> ToSocketAddrs for &'b [SocketAddr] {
-    type Iter = std::iter::Cloned<std::slice::Iter<'a, SocketAddr>>;
+    type Iter = std::iter::Cloned<std::slice::Iter<'b, SocketAddr>>;
 
-    fn to_socket_addrs(
+    fn to_socket_addrs<'a>(
-        &self,
+        &'a self,
-    ) -> ret!(
+    ) -> Pin<Box<dyn Future<Output = io::Result<Self::Iter>> + 'a + Send>> {
-        impl Future<Output = Self::Iter>,
+        Box::pin(future::ready(Ok(self.iter().cloned())))
-        ToSocketAddrsFuture<Self::Iter>
-    ) {
-        ToSocketAddrsFuture::Ready(Ok(self.iter().cloned()))
     }
 }
 
 impl<T: ToSocketAddrs + ?Sized> ToSocketAddrs for &T {
     type Iter = T::Iter;
 
-    fn to_socket_addrs(
+    fn to_socket_addrs<'a>(
-        &self,
+        &'a self,
-    ) -> ret!(
+    ) -> Pin<Box<dyn Future<Output = io::Result<Self::Iter>> + 'a + Send>> {
-        impl Future<Output = Self::Iter>,
-        ToSocketAddrsFuture<Self::Iter>
-    ) {
         (**self).to_socket_addrs()
     }
 }
@@ -274,12 +180,9 @@ impl<T: ToSocketAddrs + ?Sized> ToSocketAddrs for &T {
 impl ToSocketAddrs for String {
     type Iter = std::vec::IntoIter<SocketAddr>;
 
-    fn to_socket_addrs(
+    fn to_socket_addrs<'a>(
-        &self,
+        &'a self,
-    ) -> ret!(
+    ) -> Pin<Box<dyn Future<Output = io::Result<Self::Iter>> + 'a + Send>> {
-        impl Future<Output = Self::Iter>,
-        ToSocketAddrsFuture<Self::Iter>
-    ) {
         (&**self).to_socket_addrs()
     }
 }