Add EitherUpgrade and generalise OrUpgrade. (#662)

core/src/upgrade/either.rs

@@ -0,0 +1,109 @@
+// Copyright 2018 Parity Technologies (UK) Ltd.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+use bytes::Bytes;
+use futures::future::Either;
+use crate::{
+    either::{EitherOutput, EitherError, EitherFuture2},
+    upgrade::{InboundUpgrade, OutboundUpgrade, UpgradeInfo}
+};
+
+/// A type to represent two possible upgrade types (inbound or outbound).
+#[derive(Debug, Clone)]
+pub enum EitherUpgrade<A, B> { A(A), B(B) }
+
+impl<A, B> UpgradeInfo for EitherUpgrade<A, B>
+where
+    A: UpgradeInfo,
+    B: UpgradeInfo
+{
+    type UpgradeId = Either<A::UpgradeId, B::UpgradeId>;
+    type NamesIter = EitherIter<A::NamesIter, B::NamesIter>;
+
+    fn protocol_names(&self) -> Self::NamesIter {
+        match self {
+            EitherUpgrade::A(a) => EitherIter::A(a.protocol_names()),
+            EitherUpgrade::B(b) => EitherIter::B(b.protocol_names())
+        }
+    }
+}
+
+impl<C, A, B, TA, TB, EA, EB> InboundUpgrade<C> for EitherUpgrade<A, B>
+where
+    A: InboundUpgrade<C, Output = TA, Error = EA>,
+    B: InboundUpgrade<C, Output = TB, Error = EB>,
+{
+    type Output = EitherOutput<TA, TB>;
+    type Error = EitherError<EA, EB>;
+    type Future = EitherFuture2<A::Future, B::Future>;
+
+    fn upgrade_inbound(self, sock: C, id: Self::UpgradeId) -> Self::Future {
+        match (self, id) {
+            (EitherUpgrade::A(a), Either::A(id)) => EitherFuture2::A(a.upgrade_inbound(sock, id)),
+            (EitherUpgrade::B(b), Either::B(id)) => EitherFuture2::B(b.upgrade_inbound(sock, id)),
+            _ => panic!("Invalid invocation of EitherUpgrade::upgrade_inbound")
+        }
+    }
+}
+
+impl<C, A, B, TA, TB, EA, EB> OutboundUpgrade<C> for EitherUpgrade<A, B>
+where
+    A: OutboundUpgrade<C, Output = TA, Error = EA>,
+    B: OutboundUpgrade<C, Output = TB, Error = EB>,
+{
+    type Output = EitherOutput<TA, TB>;
+    type Error = EitherError<EA, EB>;
+    type Future = EitherFuture2<A::Future, B::Future>;
+
+    fn upgrade_outbound(self, sock: C, id: Self::UpgradeId) -> Self::Future {
+        match (self, id) {
+            (EitherUpgrade::A(a), Either::A(id)) => EitherFuture2::A(a.upgrade_outbound(sock, id)),
+            (EitherUpgrade::B(b), Either::B(id)) => EitherFuture2::B(b.upgrade_outbound(sock, id)),
+            _ => panic!("Invalid invocation of EitherUpgrade::upgrade_outbound")
+        }
+    }
+}
+
+/// A type to represent two possible `Iterator` types.
+#[derive(Debug, Clone)]
+pub enum EitherIter<A, B> { A(A), B(B) }
+
+impl<A, B, AId, BId> Iterator for EitherIter<A, B>
+where
+    A: Iterator<Item = (Bytes, AId)>,
+    B: Iterator<Item = (Bytes, BId)>,
+{
+    type Item = (Bytes, Either<AId, BId>);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        match self {
+            EitherIter::A(a) => a.next().map(|(name, id)| (name, Either::A(id))),
+            EitherIter::B(b) => b.next().map(|(name, id)| (name, Either::B(id)))
+        }
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        match self {
+            EitherIter::A(a) => a.size_hint(),
+            EitherIter::B(b) => b.size_hint()
+        }
+    }
+}
+