Auto merge of #67419 - Centril:rollup-v7b0ypv, r=Centril

Rollup of 8 pull requests

Successful merges:

 - #67189 (Unify binop wording)
 - #67270 (std: Implement `LineWriter::write_vectored`)
 - #67286 (Fix the configure.py TOML field for a couple LLVM options)
 - #67321 (make htons const fn)
 - #67382 (Remove some unnecessary `ATTR_*` constants.)
 - #67389 (Remove `SO_NOSIGPIPE` dummy variable on platforms that don't use it.)
 - #67394 (Remove outdated references to @T from comments)
 - #67406 (Suggest associated type when the specified one cannot be found)

Failed merges:

r? @ghost

5 files changed, 188 insertions, 35 deletions

diff --git a/src/libstd/io/buffered.rs b/src/libstd/io/buffered.rs
index 8e81b292f6f..df259dc2f56 100644
--- a/src/libstd/io/buffered.rs
+++ b/src/libstd/io/buffered.rs
@@ -989,6 +989,68 @@ impl<W: Write> Write for LineWriter<W> {
         }
     }
 
+    // Vectored writes are very similar to the writes above, but adjusted for
+    // the list of buffers that we have to write.
+    fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
+        if self.need_flush {
+            self.flush()?;
+        }
+
+        // Find the last newline, and failing that write the whole buffer
+        let last_newline = bufs
+            .iter()
+            .enumerate()
+            .rev()
+            .filter_map(|(i, buf)| {
+                let pos = memchr::memrchr(b'\n', buf)?;
+                Some((i, pos))
+            })
+            .next();
+        let (i, j) = match last_newline {
+            Some(pair) => pair,
+            None => return self.inner.write_vectored(bufs),
+        };
+        let (prefix, suffix) = bufs.split_at(i);
+        let (buf, suffix) = suffix.split_at(1);
+        let buf = &buf[0];
+
+        // Write everything up to the last newline, flushing afterwards. Note
+        // that only if we finished our entire `write_vectored` do we try the
+        // subsequent
+        // `write`
+        let mut n = 0;
+        let prefix_amt = prefix.iter().map(|i| i.len()).sum();
+        if prefix_amt > 0 {
+            n += self.inner.write_vectored(prefix)?;
+            self.need_flush = true;
+        }
+        if n == prefix_amt {
+            match self.inner.write(&buf[..=j]) {
+                Ok(m) => n += m,
+                Err(e) if n == 0 => return Err(e),
+                Err(_) => return Ok(n),
+            }
+            self.need_flush = true;
+        }
+        if self.flush().is_err() || n != j + 1 + prefix_amt {
+            return Ok(n);
+        }
+
+        // ... and now write out everything remaining
+        match self.inner.write(&buf[j + 1..]) {
+            Ok(i) => n += i,
+            Err(_) => return Ok(n),
+        }
+
+        if suffix.iter().map(|s| s.len()).sum::<usize>() == 0 {
+            return Ok(n)
+        }
+        match self.inner.write_vectored(suffix) {
+            Ok(i) => Ok(n + i),
+            Err(_) => Ok(n),
+        }
+    }
+
     fn flush(&mut self) -> io::Result<()> {
         self.inner.flush()?;
         self.need_flush = false;
@@ -1015,7 +1077,7 @@ where
 #[cfg(test)]
 mod tests {
     use crate::io::prelude::*;
-    use crate::io::{self, BufReader, BufWriter, LineWriter, SeekFrom};
+    use crate::io::{self, BufReader, BufWriter, LineWriter, SeekFrom, IoSlice};
     use crate::sync::atomic::{AtomicUsize, Ordering};
     use crate::thread;
 
@@ -1483,4 +1545,112 @@ mod tests {
 
         assert_eq!(l.write(b"a").unwrap_err().kind(), io::ErrorKind::Other)
     }
+
+    #[test]
+    fn line_vectored() {
+        let mut a = LineWriter::new(Vec::new());
+        assert_eq!(
+            a.write_vectored(&[
+                IoSlice::new(&[]),
+                IoSlice::new(b"\n"),
+                IoSlice::new(&[]),
+                IoSlice::new(b"a"),
+            ])
+            .unwrap(),
+            2,
+        );
+        assert_eq!(a.get_ref(), b"\n");
+
+        assert_eq!(
+            a.write_vectored(&[
+                IoSlice::new(&[]),
+                IoSlice::new(b"b"),
+                IoSlice::new(&[]),
+                IoSlice::new(b"a"),
+                IoSlice::new(&[]),
+                IoSlice::new(b"c"),
+            ])
+            .unwrap(),
+            3,
+        );
+        assert_eq!(a.get_ref(), b"\n");
+        a.flush().unwrap();
+        assert_eq!(a.get_ref(), b"\nabac");
+        assert_eq!(a.write_vectored(&[]).unwrap(), 0);
+        assert_eq!(
+            a.write_vectored(&[
+                IoSlice::new(&[]),
+                IoSlice::new(&[]),
+                IoSlice::new(&[]),
+                IoSlice::new(&[]),
+            ])
+            .unwrap(),
+            0,
+        );
+        assert_eq!(a.write_vectored(&[IoSlice::new(b"a\nb"),]).unwrap(), 3);
+        assert_eq!(a.get_ref(), b"\nabaca\n");
+    }
+
+    #[test]
+    fn line_vectored_partial_and_errors() {
+        enum Call {
+            Write { inputs: Vec<&'static [u8]>, output: io::Result<usize> },
+            Flush { output: io::Result<()> },
+        }
+        struct Writer {
+            calls: Vec<Call>,
+        }
+
+        impl Write for Writer {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+                self.write_vectored(&[IoSlice::new(buf)])
+            }
+
+            fn write_vectored(&mut self, buf: &[IoSlice<'_>]) -> io::Result<usize> {
+                match self.calls.pop().unwrap() {
+                    Call::Write { inputs, output } => {
+                        assert_eq!(inputs, buf.iter().map(|b| &**b).collect::<Vec<_>>());
+                        output
+                    }
+                    _ => panic!("unexpected call to write"),
+                }
+            }
+
+            fn flush(&mut self) -> io::Result<()> {
+                match self.calls.pop().unwrap() {
+                    Call::Flush { output } => output,
+                    _ => panic!("unexpected call to flush"),
+                }
+            }
+        }
+
+        impl Drop for Writer {
+            fn drop(&mut self) {
+                if !thread::panicking() {
+                    assert_eq!(self.calls.len(), 0);
+                }
+            }
+        }
+
+        // partial writes keep going
+        let mut a = LineWriter::new(Writer { calls: Vec::new() });
+        a.write_vectored(&[IoSlice::new(&[]), IoSlice::new(b"abc")]).unwrap();
+        a.get_mut().calls.push(Call::Flush { output: Ok(()) });
+        a.get_mut().calls.push(Call::Write { inputs: vec![b"bcx\n"], output: Ok(4) });
+        a.get_mut().calls.push(Call::Write { inputs: vec![b"abcx\n"], output: Ok(1) });
+        a.write_vectored(&[IoSlice::new(b"x"), IoSlice::new(b"\n")]).unwrap();
+        a.get_mut().calls.push(Call::Flush { output: Ok(()) });
+        a.flush().unwrap();
+
+        // erroneous writes stop and don't write more
+        a.get_mut().calls.push(Call::Write { inputs: vec![b"x\n"], output: Err(err()) });
+        assert_eq!(a.write_vectored(&[IoSlice::new(b"x"), IoSlice::new(b"\na")]).unwrap(), 2);
+        a.get_mut().calls.push(Call::Flush { output: Ok(()) });
+        a.get_mut().calls.push(Call::Write { inputs: vec![b"x\n"], output: Ok(2) });
+        a.flush().unwrap();
+
+        fn err() -> io::Error {
+            io::Error::new(io::ErrorKind::Other, "x")
+        }
+    }
 }
diff --git a/src/libstd/net/addr.rs b/src/libstd/net/addr.rs
index d5f4ece726b..a9d88370c61 100644
--- a/src/libstd/net/addr.rs
+++ b/src/libstd/net/addr.rs
@@ -4,7 +4,7 @@ use crate::hash;
 use crate::io;
 use crate::iter;
 use crate::mem;
-use crate::net::{hton, ntoh, IpAddr, Ipv4Addr, Ipv6Addr};
+use crate::net::{htons, ntohs, IpAddr, Ipv4Addr, Ipv6Addr};
 use crate::option;
 use crate::slice;
 use crate::sys::net::netc as c;
@@ -276,7 +276,7 @@ impl SocketAddrV4 {
         SocketAddrV4 {
             inner: c::sockaddr_in {
                 sin_family: c::AF_INET as c::sa_family_t,
-                sin_port: hton(port),
+                sin_port: htons(port),
                 sin_addr: *ip.as_inner(),
                 ..unsafe { mem::zeroed() }
             },
@@ -326,7 +326,7 @@ impl SocketAddrV4 {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn port(&self) -> u16 {
-        ntoh(self.inner.sin_port)
+        ntohs(self.inner.sin_port)
     }
 
     /// Changes the port number associated with this socket address.
@@ -342,7 +342,7 @@ impl SocketAddrV4 {
     /// ```
     #[stable(feature = "sockaddr_setters", since = "1.9.0")]
     pub fn set_port(&mut self, new_port: u16) {
-        self.inner.sin_port = hton(new_port);
+        self.inner.sin_port = htons(new_port);
     }
 }
 
@@ -368,7 +368,7 @@ impl SocketAddrV6 {
         SocketAddrV6 {
             inner: c::sockaddr_in6 {
                 sin6_family: c::AF_INET6 as c::sa_family_t,
-                sin6_port: hton(port),
+                sin6_port: htons(port),
                 sin6_addr: *ip.as_inner(),
                 sin6_flowinfo: flowinfo,
                 sin6_scope_id: scope_id,
@@ -420,7 +420,7 @@ impl SocketAddrV6 {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn port(&self) -> u16 {
-        ntoh(self.inner.sin6_port)
+        ntohs(self.inner.sin6_port)
     }
 
     /// Changes the port number associated with this socket address.
@@ -436,7 +436,7 @@ impl SocketAddrV6 {
     /// ```
     #[stable(feature = "sockaddr_setters", since = "1.9.0")]
     pub fn set_port(&mut self, new_port: u16) {
-        self.inner.sin6_port = hton(new_port);
+        self.inner.sin6_port = htons(new_port);
     }
 
     /// Returns the flow information associated with this address.
diff --git a/src/libstd/net/mod.rs b/src/libstd/net/mod.rs
index b68146939fd..8652ed8b046 100644
--- a/src/libstd/net/mod.rs
+++ b/src/libstd/net/mod.rs
@@ -85,21 +85,10 @@ pub enum Shutdown {
     Both,
 }
 
-#[doc(hidden)]
-trait NetInt {
-    fn from_be(i: Self) -> Self;
-    fn to_be(&self) -> Self;
-}
-macro_rules! doit {
-    ($($t:ident)*) => ($(impl NetInt for $t {
-        fn from_be(i: Self) -> Self { <$t>::from_be(i) }
-        fn to_be(&self) -> Self { <$t>::to_be(*self) }
-    })*)
-}
-doit! { i8 i16 i32 i64 isize u8 u16 u32 u64 usize }
-
-fn hton<I: NetInt>(i: I) -> I { i.to_be() }
-fn ntoh<I: NetInt>(i: I) -> I { I::from_be(i) }
+#[inline]
+const fn htons(i: u16) -> u16 { i.to_be() }
+#[inline]
+const fn ntohs(i: u16) -> u16 { u16::from_be(i) }
 
 fn each_addr<A: ToSocketAddrs, F, T>(addr: A, mut f: F) -> io::Result<T>
     where F: FnMut(io::Result<&SocketAddr>) -> io::Result<T>
diff --git a/src/libstd/sys/unix/net.rs b/src/libstd/sys/unix/net.rs
index 946b2b9d8de..5d101ed1f2e 100644
--- a/src/libstd/sys/unix/net.rs
+++ b/src/libstd/sys/unix/net.rs
@@ -28,14 +28,6 @@ use libc::SOCK_CLOEXEC;
 #[cfg(not(target_os = "linux"))]
 const SOCK_CLOEXEC: c_int = 0;
 
-// Another conditional constant for name resolution: Macos et iOS use
-// SO_NOSIGPIPE as a setsockopt flag to disable SIGPIPE emission on socket.
-// Other platforms do otherwise.
-#[cfg(target_vendor = "apple")]
-use libc::SO_NOSIGPIPE;
-#[cfg(not(target_vendor = "apple"))]
-const SO_NOSIGPIPE: c_int = 0;
-
 pub struct Socket(FileDesc);
 
 pub fn init() {}
@@ -89,9 +81,12 @@ impl Socket {
             let fd = FileDesc::new(fd);
             fd.set_cloexec()?;
             let socket = Socket(fd);
-            if cfg!(target_vendor = "apple") {
-                setsockopt(&socket, libc::SOL_SOCKET, SO_NOSIGPIPE, 1)?;
-            }
+
+            // macOS and iOS use `SO_NOSIGPIPE` as a `setsockopt`
+            // flag to disable `SIGPIPE` emission on socket.
+            #[cfg(target_vendor = "apple")]
+            setsockopt(&socket, libc::SOL_SOCKET, libc::SO_NOSIGPIPE, 1)?;
+
             Ok(socket)
         }
     }
diff --git a/src/libstd/sys/vxworks/net.rs b/src/libstd/sys/vxworks/net.rs
index 85f5fcff2c2..54466ff2c2e 100644
--- a/src/libstd/sys/vxworks/net.rs
+++ b/src/libstd/sys/vxworks/net.rs
@@ -19,7 +19,6 @@ pub extern crate libc as netc;
 pub type wrlen_t = size_t;
 
 const SOCK_CLOEXEC: c_int = 0;
-const SO_NOSIGPIPE: c_int = 0;
 
 pub struct Socket(FileDesc);