Fix compilation bug with Rust 1.68.2 caused by an unnecessary HRTB (for<'a> ...) that Rust 1.69.0+ are fine with but 1.68.2 is not (perhaps due to rust-lang/rust#103695 which was fixed in Rust 1.69.0).

Also reorder XfrMiddlewareSvc generic types to match the order used in other middleware services, i.e. add the extra type XDP at the end, not before RequestMeta.

Also rename Metadata to RequestMeta as in other middleware services.

(and fix a comment that is ahead of its time, there is no ZoneMaintainer yet in this branch)

Author: ximon18

src/net/server/middleware/xfr.rs

@@ -106,7 +106,7 @@ const MAX_TCP_MSG_BYTE_LEN: u16 = u16::MAX;
 ///
 /// [module documentation]: crate::net::server::middleware::xfr
 #[derive(Clone, Debug)]
-pub struct XfrMiddlewareSvc<RequestOctets, NextSvc, XDP, Metadata = ()> {
+pub struct XfrMiddlewareSvc<RequestOctets, NextSvc, RequestMeta, XDP> {
     /// The upstream [`Service`] to pass requests to and receive responses
     /// from.
     next_svc: NextSvc,
@@ -123,13 +123,13 @@ pub struct XfrMiddlewareSvc<RequestOctets, NextSvc, XDP, Metadata = ()> {
     /// may run concurrently.
     batcher_semaphore: Arc<Semaphore>,
 
-    _phantom: PhantomData<(RequestOctets, Metadata)>,
+    _phantom: PhantomData<(RequestOctets, RequestMeta)>,
 }
 
-impl<RequestOctets, NextSvc, XDP, Metadata>
-    XfrMiddlewareSvc<RequestOctets, NextSvc, XDP, Metadata>
+impl<RequestOctets, NextSvc, RequestMeta, XDP>
+    XfrMiddlewareSvc<RequestOctets, NextSvc, RequestMeta, XDP>
 where
-    XDP: XfrDataProvider<Metadata>,
+    XDP: XfrDataProvider<RequestMeta>,
 {
     /// Creates a new instance of this middleware.
     ///
@@ -158,16 +158,16 @@ where
     }
 }
 
-impl<RequestOctets, NextSvc, XDP, Metadata>
-    XfrMiddlewareSvc<RequestOctets, NextSvc, XDP, Metadata>
+impl<RequestOctets, NextSvc, RequestMeta, XDP>
+    XfrMiddlewareSvc<RequestOctets, NextSvc, RequestMeta, XDP>
 where
     RequestOctets: Octets + Send + Sync + 'static + Unpin,
     for<'a> <RequestOctets as octseq::Octets>::Range<'a>: Send + Sync,
     NextSvc: Service<RequestOctets, ()> + Clone + Send + Sync + 'static,
     NextSvc::Future: Send + Sync + Unpin,
     NextSvc::Target: Composer + Default + Send + Sync,
     NextSvc::Stream: Send + Sync,
-    XDP: XfrDataProvider<Metadata>,
+    XDP: XfrDataProvider<RequestMeta>,
     XDP::Diff: Debug + 'static,
     for<'a> <XDP::Diff as ZoneDiff>::Stream<'a>: Send,
 {
@@ -178,7 +178,7 @@ where
     pub async fn preprocess(
         zone_walking_semaphore: Arc<Semaphore>,
         batcher_semaphore: Arc<Semaphore>,
-        req: &Request<RequestOctets, Metadata>,
+        req: &Request<RequestOctets, RequestMeta>,
         xfr_data_provider: XDP,
     ) -> Result<
         ControlFlow<
@@ -807,19 +807,19 @@ where
 
 //--- impl Service
 
-impl<RequestOctets, NextSvc, XDP, Metadata> Service<RequestOctets, Metadata>
-    for XfrMiddlewareSvc<RequestOctets, NextSvc, XDP, Metadata>
+impl<RequestOctets, NextSvc, RequestMeta, XDP>
+    Service<RequestOctets, RequestMeta>
+    for XfrMiddlewareSvc<RequestOctets, NextSvc, RequestMeta, XDP>
 where
     RequestOctets: Octets + Send + Sync + Unpin + 'static,
     for<'a> <RequestOctets as octseq::Octets>::Range<'a>: Send + Sync,
     NextSvc: Service<RequestOctets, ()> + Clone + Send + Sync + 'static,
     NextSvc::Future: Send + Sync + Unpin,
     NextSvc::Target: Composer + Default + Send + Sync,
     NextSvc::Stream: Send + Sync,
-    XDP: XfrDataProvider<Metadata> + Clone + Sync + Send + 'static,
+    XDP: XfrDataProvider<RequestMeta> + Clone + Sync + Send + 'static,
     XDP::Diff: Debug + Sync,
-    for<'a> <XDP::Diff as ZoneDiff>::Stream<'a>: Send,
-    Metadata: Clone + Default + Sync + Send + 'static,
+    RequestMeta: Clone + Default + Sync + Send + 'static,
 {
     type Target = NextSvc::Target;
     type Stream = XfrMiddlewareStream<
@@ -831,7 +831,7 @@ where
 
     fn call(
         &self,
-        request: Request<RequestOctets, Metadata>,
+        request: Request<RequestOctets, RequestMeta>,
     ) -> Self::Future {
         let request = request.clone();
         let next_svc = self.next_svc.clone();
@@ -902,8 +902,8 @@ pub enum XfrDataProviderError {
 //------------ Transferable ---------------------------------------------------
 
 /// A provider of data needed for responding to XFR requests.
-pub trait XfrDataProvider<Metadata = ()> {
-    type Diff: ZoneDiff + Send;
+pub trait XfrDataProvider<RequestMeta = ()> {
+    type Diff: ZoneDiff + Send + Sync;
 
     /// Request data needed to respond to an XFR request.
     ///
@@ -918,7 +918,7 @@ pub trait XfrDataProvider<Metadata = ()> {
     #[allow(clippy::type_complexity)]
     fn request<Octs>(
         &self,
-        req: &Request<Octs, Metadata>,
+        req: &Request<Octs, RequestMeta>,
         diff_from: Option<Serial>,
     ) -> Pin<
         Box<
@@ -938,16 +938,16 @@ pub trait XfrDataProvider<Metadata = ()> {
 
 //--- impl XfrDataProvider for Deref<XfrDataProvider>
 
-impl<Metadata, T, U> XfrDataProvider<Metadata> for U
+impl<RequestMeta, T, U> XfrDataProvider<RequestMeta> for U
 where
-    T: XfrDataProvider<Metadata> + 'static,
+    T: XfrDataProvider<RequestMeta> + 'static,
     U: Deref<Target = T>,
 {
     type Diff = T::Diff;
 
     fn request<Octs>(
         &self,
-        req: &Request<Octs, Metadata>,
+        req: &Request<Octs, RequestMeta>,
         diff_from: Option<Serial>,
     ) -> Pin<
         Box<
@@ -970,7 +970,7 @@ where
 
 //--- impl XfrDataProvider for Zone
 
-impl<Metadata> XfrDataProvider<Metadata> for Zone {
+impl<RequestMeta> XfrDataProvider<RequestMeta> for Zone {
     type Diff = EmptyZoneDiff;
 
     /// Request data needed to respond to an XFR request.
@@ -981,7 +981,7 @@ impl<Metadata> XfrDataProvider<Metadata> for Zone {
     /// Returns Err if the requested zone is not this zone.
     fn request<Octs>(
         &self,
-        req: &Request<Octs, Metadata>,
+        req: &Request<Octs, RequestMeta>,
         _diff_from: Option<Serial>,
     ) -> Pin<
         Box<
@@ -1013,7 +1013,7 @@ impl<Metadata> XfrDataProvider<Metadata> for Zone {
 
 //--- impl XfrDataProvider for ZoneTree
 
-impl<Metadata> XfrDataProvider<Metadata> for ZoneTree {
+impl<RequestMeta> XfrDataProvider<RequestMeta> for ZoneTree {
     type Diff = EmptyZoneDiff;
 
     /// Request data needed to respond to an XFR request.
@@ -1024,7 +1024,7 @@ impl<Metadata> XfrDataProvider<Metadata> for ZoneTree {
     /// Returns Err if the requested zone is not this zone tree.
     fn request<Octs>(
         &self,
-        req: &Request<Octs, Metadata>,
+        req: &Request<Octs, RequestMeta>,
         _diff_from: Option<Serial>,
     ) -> Pin<
         Box<
@@ -2057,7 +2057,7 @@ JAIN-BB.JAIN.AD.JP. IN A   192.41.197.2
     async fn get_zone_soa(zone: &Zone) -> Soa<Name<Bytes>> {
         let read = zone.read();
         let zone_soa_answer =
-            XfrMiddlewareSvc::<Vec<u8>, TestNextSvc, Zone>::read_soa(
+            XfrMiddlewareSvc::<Vec<u8>, TestNextSvc, (), Zone>::read_soa(
                 &read,
                 zone.apex_name().to_owned(),
             )
@@ -2176,9 +2176,9 @@ JAIN-BB.JAIN.AD.JP. IN A   192.41.197.2
         )
     }
 
-    async fn do_preprocess<Metadata, XDP: XfrDataProvider<Metadata>>(
+    async fn do_preprocess<RequestMeta, XDP: XfrDataProvider<RequestMeta>>(
         zone: XDP,
-        req: &Request<Vec<u8>, Metadata>,
+        req: &Request<Vec<u8>, RequestMeta>,
     ) -> Result<
         ControlFlow<
             XfrMiddlewareStream<
@@ -2193,7 +2193,7 @@ JAIN-BB.JAIN.AD.JP. IN A   192.41.197.2
         XDP::Diff: Debug + 'static,
         for<'a> <XDP::Diff as ZoneDiff>::Stream<'a>: Send,
     {
-        XfrMiddlewareSvc::<Vec<u8>, TestNextSvc, XDP, Metadata>::preprocess(
+        XfrMiddlewareSvc::<Vec<u8>, TestNextSvc, RequestMeta, XDP>::preprocess(
             Arc::new(Semaphore::new(1)),
             Arc::new(Semaphore::new(1)),
             req,

src/net/server/tests/integration.rs

@@ -158,9 +158,8 @@ async fn server_tests(#[files("test-data/server/*.rpl")] rpl_file: PathBuf) {
     let svc =
         EdnsMiddlewareSvc::new(svc).enable(server_config.edns_tcp_keepalive);
 
-    // 4. XFR(-in) middleware service (XFR-out is handled by the
-    //    ZoneMaintainer).
-    let svc = XfrMiddlewareSvc::<Vec<u8>, _, _, Option<Arc<Key>>>::new(
+    // 4. XFR(-in) middleware service.
+    let svc = XfrMiddlewareSvc::<Vec<u8>, _, Option<Arc<Key>>, _>::new(
         svc, zones, 1,
     );