Convert pipes::Buffer into a struct

Author: erickt

src/libcore/pipes.rs

@@ -140,10 +140,19 @@ pub fn BufferHeader() -> BufferHeader{
 
 // This is for protocols to associate extra data to thread around.
 #[doc(hidden)]
+#[cfg(stage0)]
 type Buffer<T: Owned> = {
     header: BufferHeader,
     data: T,
 };
+#[doc(hidden)]
+#[cfg(stage1)]
+#[cfg(stage2)]
+#[cfg(stage3)]
+pub struct Buffer<T: Owned> {
+    header: BufferHeader,
+    data: T,
+}
 
 struct PacketHeader {
     mut state: State,
@@ -230,6 +239,7 @@ pub fn mk_packet<T: Owned>() -> Packet<T> {
 }
 
 #[doc(hidden)]
+#[cfg(stage0)]
 fn unibuffer<T: Owned>() -> ~Buffer<Packet<T>> {
     let b = ~{
         header: BufferHeader(),
@@ -245,6 +255,25 @@ fn unibuffer<T: Owned>() -> ~Buffer<Packet<T>> {
     move b
 }
 
+#[doc(hidden)]
+#[cfg(stage1)]
+#[cfg(stage2)]
+#[cfg(stage3)]
+fn unibuffer<T: Owned>() -> ~Buffer<Packet<T>> {
+    let b = ~Buffer {
+        header: BufferHeader(),
+        data: Packet {
+            header: PacketHeader(),
+            payload: None,
+        }
+    };
+
+    unsafe {
+        b.data.header.buffer = reinterpret_cast(&b);
+    }
+    move b
+}
+
 #[doc(hidden)]
 pub fn packet<T: Owned>() -> *Packet<T> {
     let b = unibuffer();

src/libsyntax/ext/pipes/pipec.rs

@@ -357,10 +357,10 @@ impl protocol: gen_init {
     fn gen_init_bounded(ext_cx: ext_ctxt) -> @ast::expr {
         debug!("gen_init_bounded");
         let buffer_fields = self.gen_buffer_init(ext_cx);
-        let buffer = quote_expr!(
-            ~{header: ::pipes::BufferHeader(),
-              data: $buffer_fields}
-        );
+        let buffer = quote_expr!(~::pipes::Buffer {
+            header: ::pipes::BufferHeader(),
+            data: $buffer_fields,
+        });
 
         let entangle_body = ext_cx.block_expr(
             ext_cx.block(

src/test/run-pass/pipe-pingpong-bounded.rs

@@ -27,7 +27,7 @@ mod pingpong {
     };
 
     pub fn init() -> (client::ping, server::ping) {
-        let buffer = ~{
+        let buffer = ~Buffer {
             header: BufferHeader(),
             data: {
                 ping: mk_packet::<ping>(),