Added Onion3 support to multiaddr (#1354)

misc/multiaddr/src/onion_addr.rs

@@ -0,0 +1,54 @@
+use std::borrow::Cow;
+use std::fmt::Debug;
+use serde::export::Formatter;
+use std::fmt;
+
+/// Represents an Onion v3 address
+#[derive(Clone)]
+pub struct Onion3Addr<'a>(Cow<'a, [u8; 35]>, u16);
+
+impl<'a> Onion3Addr<'a> {
+    /// Return the hash of the public key as bytes
+    pub fn hash(&self) -> &[u8; 35] {
+        self.0.as_ref()
+    }
+
+    /// Return the port
+    pub fn port(&self) -> u16 {
+        self.1
+    }
+
+    /// Consume this instance and create an owned version containing the same address
+    pub fn acquire<'b>(self) -> Onion3Addr<'b> {
+        Self(Cow::Owned(self.0.into_owned()), self.1)
+    }
+}
+
+impl PartialEq for Onion3Addr<'_> {
+    fn eq(&self, other: &Self) -> bool {
+        self.1 == other.1 && self.0[..] == other.0[..]
+    }
+}
+
+impl Eq for Onion3Addr<'_> { }
+
+impl From<([u8; 35], u16)> for Onion3Addr<'_> {
+    fn from(parts: ([u8; 35], u16)) -> Self {
+        Self(Cow::Owned(parts.0), parts.1)
+    }
+}
+
+impl<'a> From<(&'a [u8; 35], u16)> for Onion3Addr<'a> {
+    fn from(parts: (&'a [u8; 35], u16)) -> Self {
+        Self(Cow::Borrowed(parts.0), parts.1)
+    }
+}
+
+impl Debug for Onion3Addr<'_> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), fmt::Error> {
+       f.debug_tuple("Onion3Addr")
+           .field(&format!("{:02x?}", &self.0[..]))
+           .field(&self.1)
+           .finish()
+    }
+}