stream: implement write_vectored

Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>

rustls/src/client/mod.rs

@@ -18,7 +18,7 @@ use crate::vecbuf::WriteV;
 use crate::log::trace;
 
 use std::sync::Arc;
-use std::io;
+use std::io::{self, IoSlice};
 use std::fmt;
 use std::mem;
 
@@ -742,6 +742,14 @@ impl io::Write for ClientSession {
         self.imp.send_some_plaintext(buf)
     }
 
+    fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
+        let mut sz = 0;
+        for buf in bufs {
+            sz += self.imp.send_some_plaintext(buf)?;
+        }
+        Ok(sz)
+    }
+
     fn flush(&mut self) -> io::Result<()> {
         self.imp.common.flush_plaintext();
         Ok(())

rustls/src/server/mod.rs

@@ -17,7 +17,7 @@ use crate::log::trace;
 use webpki;
 
 use std::sync::Arc;
-use std::io;
+use std::io::{self, IoSlice};
 use std::fmt;
 
 #[macro_use]
@@ -652,6 +652,14 @@ impl io::Write for ServerSession {
         self.imp.send_some_plaintext(buf)
     }
 
+    fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
+        let mut sz = 0;
+        for buf in bufs {
+            sz += self.imp.send_some_plaintext(buf)?;
+        }
+        Ok(sz)
+    }
+
     fn flush(&mut self) -> io::Result<()> {
         self.imp.common.flush_plaintext();
         Ok(())

rustls/src/stream.rs

@@ -1,4 +1,4 @@
-use std::io::{Read, Write, Result};
+use std::io::{IoSlice, Read, Write, Result};
 use crate::session::Session;
 
 /// This type implements `io::Read` and `io::Write`, encapsulating
@@ -68,6 +68,19 @@ impl<'a, S, T> Write for Stream<'a, S, T> where S: 'a + Session, T: 'a + Read +
         Ok(len)
     }
 
+    fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize> {
+        self.complete_prior_io()?;
+
+        let len = self.sess.write_vectored(bufs)?;
+
+        // Try to write the underlying transport here, but don't let
+        // any errors mask the fact we've consumed `len` bytes.
+        // Callers will learn of permanent errors on the next call.
+        let _ = self.sess.complete_io(self.sock);
+
+        Ok(len)
+    }
+
     fn flush(&mut self) -> Result<()> {
         self.complete_prior_io()?;