From fa8fc4b2b5bc66aa7b10a04a895c33de0d5e8185 Mon Sep 17 00:00:00 2001
From: Ben Blum <bblum@andrew.cmu.edu>
Date: Tue, 14 Aug 2012 20:48:37 -0400
Subject: [PATCH] Add 1shot pipe chan_one/port_one type aliases and convert
 std::sync to use them

---
 src/libcore/pipes.rs | 19 ++++++++++++-------
 src/libstd/sync.rs   | 16 ++++++++--------
 2 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/src/libcore/pipes.rs b/src/libcore/pipes.rs
index 4f39c42137cf..bc6d89e92b6c 100644
--- a/src/libcore/pipes.rs
+++ b/src/libcore/pipes.rs
@@ -90,7 +90,8 @@ export send_packet, recv_packet, send, recv, try_recv, peek;
 export select, select2, selecti, select2i, selectable;
 export spawn_service, spawn_service_recv;
 export stream, port, chan, shared_chan, port_set, channel;
-export oneshot, recv_one, try_recv_one, send_one, try_send_one;
+export oneshot, chan_one, port_one;
+export recv_one, try_recv_one, send_one, try_send_one;
 
 #[doc(hidden)]
 const SPIN_COUNT: uint = 0;
@@ -1144,9 +1145,13 @@ proto! oneshot {
     }
 }
 
+/// The send end of a oneshot pipe.
+type chan_one<T: send> = oneshot::client::oneshot<T>;
+/// The receive end of a oneshot pipe.
+type port_one<T: send> = oneshot::server::oneshot<T>;
+
 /// Initialiase a (send-endpoint, recv-endpoint) oneshot pipe pair.
-fn oneshot<T: send>() -> (oneshot::client::oneshot<T>,
-                          oneshot::server::oneshot<T>) {
+fn oneshot<T: send>() -> (chan_one<T>, port_one<T>) {
     oneshot::init()
 }
 
@@ -1154,13 +1159,13 @@ fn oneshot<T: send>() -> (oneshot::client::oneshot<T>,
  * Receive a message from a oneshot pipe, failing if the connection was
  * closed.
  */
-fn recv_one<T: send>(+port: oneshot::server::oneshot<T>) -> T {
+fn recv_one<T: send>(+port: port_one<T>) -> T {
     let oneshot::send(message) = recv(port);
     message
 }
 
 /// Receive a message from a oneshot pipe unless the connection was closed.
-fn try_recv_one<T: send> (+port: oneshot::server::oneshot<T>) -> option<T> {
+fn try_recv_one<T: send> (+port: port_one<T>) -> option<T> {
     let message = try_recv(port);
 
     if message == none { none }
@@ -1171,7 +1176,7 @@ fn try_recv_one<T: send> (+port: oneshot::server::oneshot<T>) -> option<T> {
 }
 
 /// Send a message on a oneshot pipe, failing if the connection was closed.
-fn send_one<T: send>(+chan: oneshot::client::oneshot<T>, +data: T) {
+fn send_one<T: send>(+chan: chan_one<T>, +data: T) {
     oneshot::client::send(chan, data);
 }
 
@@ -1179,7 +1184,7 @@ fn send_one<T: send>(+chan: oneshot::client::oneshot<T>, +data: T) {
  * Send a message on a oneshot pipe, or return false if the connection was
  * closed.
  */
-fn try_send_one<T: send>(+chan: oneshot::client::oneshot<T>, +data: T)
+fn try_send_one<T: send>(+chan: chan_one<T>, +data: T)
         -> bool {
     oneshot::client::try_send(chan, data).is_some()
 }
diff --git a/src/libstd/sync.rs b/src/libstd/sync.rs
index 4233c351cf1e..85043699595f 100644
--- a/src/libstd/sync.rs
+++ b/src/libstd/sync.rs
@@ -18,8 +18,8 @@ import unsafe::{Exclusive, exclusive};
  ****************************************************************************/
 
 // Each waiting task receives on one of these. FIXME #3125 make these oneshot.
-type wait_end = pipes::port<()>;
-type signal_end = pipes::chan<()>;
+type wait_end = pipes::port_one<()>;
+type signal_end = pipes::chan_one<()>;
 // A doubly-ended queue of waiting tasks.
 struct waitqueue { head: pipes::port<signal_end>;
                    tail: pipes::chan<signal_end>; }
@@ -30,7 +30,7 @@ fn signal_waitqueue(q: &waitqueue) -> bool {
     if q.head.peek() {
         // Pop and send a wakeup signal. If the waiter was killed, its port
         // will have closed. Keep trying until we get a live task.
-        if q.head.recv().try_send(()) {
+        if pipes::try_send_one(q.head.recv(), ()) {
             true
         } else {
             signal_waitqueue(q)
@@ -43,7 +43,7 @@ fn signal_waitqueue(q: &waitqueue) -> bool {
 fn broadcast_waitqueue(q: &waitqueue) -> uint {
     let mut count = 0;
     while q.head.peek() {
-        if q.head.recv().try_send(()) {
+        if pipes::try_send_one(q.head.recv(), ()) {
             count += 1;
         }
     }
@@ -80,7 +80,7 @@ impl<Q: send> &sem<Q> {
                 state.count -= 1;
                 if state.count < 0 {
                     // Create waiter nobe.
-                    let (signal_end, wait_end) = pipes::stream();
+                    let (signal_end, wait_end) = pipes::oneshot();
                     // Tell outer scope we need to block.
                     waiter_nobe = some(wait_end);
                     // Enqueue ourself.
@@ -92,7 +92,7 @@ impl<Q: send> &sem<Q> {
         /* for 1000.times { task::yield(); } */
         // Need to wait outside the exclusive.
         if waiter_nobe.is_some() {
-            let _ = option::unwrap(waiter_nobe).recv();
+            let _ = pipes::recv_one(option::unwrap(waiter_nobe));
         }
     }
     fn release() {
@@ -151,7 +151,7 @@ impl &condvar {
     /// Atomically drop the associated lock, and block until a signal is sent.
     fn wait() {
         // Create waiter nobe.
-        let (signal_end, wait_end) = pipes::stream();
+        let (signal_end, wait_end) = pipes::oneshot();
         let mut signal_end = some(signal_end);
         let mut reacquire = none;
         unsafe {
@@ -177,7 +177,7 @@ impl &condvar {
         }
         // Unconditionally "block". (Might not actually block if a signaller
         // did send -- I mean 'unconditionally' in contrast with acquire().)
-        let _ = wait_end.recv();
+        let _ = pipes::recv_one(wait_end);
 
         // This is needed for a failing condition variable to reacquire the
         // mutex during unwinding. As long as the wrapper (mutex, etc) is