core: Implement From<T> for Option<T>

src/libcore/option.rs

@@ -142,6 +142,7 @@
 use self::Option::*;
 
 use clone::Clone;
+use convert::From;
 use default::Default;
 use iter::ExactSizeIterator;
 use iter::{Iterator, DoubleEndedIterator, FromIterator, IntoIterator};
@@ -710,6 +711,14 @@ impl<T> Default for Option<T> {
     fn default() -> Option<T> { None }
 }
 
+#[unstable(feature = "option_from", reason = "recently added", issue = "0")]
+impl<T> From<T> for Option<T> {
+    #[inline]
+    fn from(t: T) -> Option<T> {
+        Some(t)
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T> IntoIterator for Option<T> {
     type Item = T;

src/libcoretest/option.rs

@@ -270,3 +270,28 @@ fn test_cloned() {
     assert_eq!(opt_ref_ref.clone().cloned(), Some(&val));
     assert_eq!(opt_ref_ref.cloned().cloned(), Some(1));
 }
+
+#[test]
+fn test_from() {
+    assert_eq!(Some(3), Option::from(3));
+}
+
+#[test]
+fn test_into_optional_parameters() {
+    use core::convert::Into;
+    fn myfunc<T, U, V>(t: T, u: U, v: V) -> Option<u8>
+        where T: Into<Option<u8>>,
+              U: Into<Option<u8>>,
+              V: Into<Option<u8>> {
+        match (t.into() ,u.into(), v.into()) {
+            (Some(t), Some(u), Some(v)) => Some(t + u + v),
+            _ => None,
+        }
+    }
+
+    assert_eq!(None, myfunc(None, 2, 3));
+    assert_eq!(None, myfunc(1, None, 3));
+    assert_eq!(None, myfunc(1, 2, None));
+    assert_eq!(Some(6), myfunc(1, 2, 3));
+    assert_eq!(Some(6), myfunc(Some(1), Some(2), Some(3)));
+}

src/libstd/net/tcp.rs

@@ -136,8 +136,9 @@ impl TcpStream {
     /// a result of setting this option. For example Unix typically returns an
     /// error of the kind `WouldBlock`, but Windows may return `TimedOut`.
     #[stable(feature = "socket_timeout", since = "1.4.0")]
-    pub fn set_read_timeout(&self, dur: Option<Duration>) -> io::Result<()> {
-        self.0.set_read_timeout(dur)
+    pub fn set_read_timeout<D>(&self, dur: D) -> io::Result<()>
+        where D: Into<Option<Duration>> {
+        self.0.set_read_timeout(dur.into())
     }
 
     /// Sets the write timeout to the timeout specified.
@@ -152,8 +153,9 @@ impl TcpStream {
     /// as a result of setting this option. For example Unix typically returns
     /// an error of the kind `WouldBlock`, but Windows may return `TimedOut`.
     #[stable(feature = "socket_timeout", since = "1.4.0")]
-    pub fn set_write_timeout(&self, dur: Option<Duration>) -> io::Result<()> {
-        self.0.set_write_timeout(dur)
+    pub fn set_write_timeout<D>(&self, dur: D) -> io::Result<()>
+        where D: Into<Option<Duration>> {
+        self.0.set_write_timeout(dur.into())
     }
 
     /// Returns the read timeout of this socket.
@@ -1059,12 +1061,12 @@ mod tests {
 
         assert_eq!(None, t!(stream.read_timeout()));
 
-        t!(stream.set_read_timeout(Some(dur)));
+        t!(stream.set_read_timeout(dur));
         assert_eq!(Some(dur), t!(stream.read_timeout()));
 
         assert_eq!(None, t!(stream.write_timeout()));
 
-        t!(stream.set_write_timeout(Some(dur)));
+        t!(stream.set_write_timeout(dur));
         assert_eq!(Some(dur), t!(stream.write_timeout()));
 
         t!(stream.set_read_timeout(None));
@@ -1081,7 +1083,7 @@ mod tests {
         let listener = t!(TcpListener::bind(&addr));
 
         let mut stream = t!(TcpStream::connect(&("localhost", addr.port())));
-        t!(stream.set_read_timeout(Some(Duration::from_millis(1000))));
+        t!(stream.set_read_timeout(Duration::from_millis(1000)));
 
         let mut buf = [0; 10];
         let start = Instant::now();
@@ -1097,7 +1099,7 @@ mod tests {
         let listener = t!(TcpListener::bind(&addr));
 
         let mut stream = t!(TcpStream::connect(&("localhost", addr.port())));
-        t!(stream.set_read_timeout(Some(Duration::from_millis(1000))));
+        t!(stream.set_read_timeout(Duration::from_millis(1000)));
 
         let mut other_end = t!(listener.accept()).0;
         t!(other_end.write_all(b"hello world"));

src/libstd/net/udp.rs

@@ -105,8 +105,9 @@ impl UdpSocket {
     /// a result of setting this option. For example Unix typically returns an
     /// error of the kind `WouldBlock`, but Windows may return `TimedOut`.
     #[stable(feature = "socket_timeout", since = "1.4.0")]
-    pub fn set_read_timeout(&self, dur: Option<Duration>) -> io::Result<()> {
-        self.0.set_read_timeout(dur)
+    pub fn set_read_timeout<D>(&self, dur: D) -> io::Result<()>
+        where D: Into<Option<Duration>> {
+        self.0.set_read_timeout(dur.into())
     }
 
     /// Sets the write timeout to the timeout specified.
@@ -121,8 +122,9 @@ impl UdpSocket {
     /// as a result of setting this option. For example Unix typically returns
     /// an error of the kind `WouldBlock`, but Windows may return `TimedOut`.
     #[stable(feature = "socket_timeout", since = "1.4.0")]
-    pub fn set_write_timeout(&self, dur: Option<Duration>) -> io::Result<()> {
-        self.0.set_write_timeout(dur)
+    pub fn set_write_timeout<D>(&self, dur: D) -> io::Result<()>
+        where D: Into<Option<Duration>> {
+        self.0.set_write_timeout(dur.into())
     }
 
     /// Returns the read timeout of this socket.
@@ -567,12 +569,12 @@ mod tests {
 
         assert_eq!(None, t!(stream.read_timeout()));
 
-        t!(stream.set_read_timeout(Some(dur)));
+        t!(stream.set_read_timeout(dur));
         assert_eq!(Some(dur), t!(stream.read_timeout()));
 
         assert_eq!(None, t!(stream.write_timeout()));
 
-        t!(stream.set_write_timeout(Some(dur)));
+        t!(stream.set_write_timeout(dur));
         assert_eq!(Some(dur), t!(stream.write_timeout()));
 
         t!(stream.set_read_timeout(None));
@@ -587,7 +589,7 @@ mod tests {
         let addr = next_test_ip4();
 
         let stream = t!(UdpSocket::bind(&addr));
-        t!(stream.set_read_timeout(Some(Duration::from_millis(1000))));
+        t!(stream.set_read_timeout(Duration::from_millis(1000)));
 
         let mut buf = [0; 10];
 
@@ -602,7 +604,7 @@ mod tests {
         let addr = next_test_ip4();
 
         let stream = t!(UdpSocket::bind(&addr));
-        t!(stream.set_read_timeout(Some(Duration::from_millis(1000))));
+        t!(stream.set_read_timeout(Duration::from_millis(1000)));
 
         t!(stream.send_to(b"hello world", &addr));