Added `subtrait!` macro for creating a blanket-impl trait that ``inherits" from one or more different traits in a few different ways (normal -> `Sized` types only, `dyn`: Sized and unsized types , `virtual`: Sized and unsized types, downcastable.)

Fortune for rsh's current commit: Curse − 凶

Cargo.lock

@@ -552,6 +552,12 @@ dependencies = [
  "winapi 0.3.9",
 ]
 
+[[package]]
+name = "mopa"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a785740271256c230f57462d3b83e52f998433a7062fc18f96d5999474a9f915"
+
 [[package]]
 name = "net2"
 version = "0.2.37"
@@ -778,6 +784,7 @@ dependencies = [
  "color-eyre",
  "cryptohelpers",
  "futures",
+ "mopa",
  "pin-project",
  "rustc_version",
  "serde",

Cargo.toml

@@ -10,6 +10,7 @@ chacha20stream = { version = "1.0.3", features = ["async"] }
 color-eyre = "0.5.11"
 cryptohelpers = { version = "1.8.1" , features = ["serialise", "full"] }
 futures = "0.3.16"
+mopa = "0.2.2"
 pin-project = "1.0.8"
 serde = { version = "1.0.126", features = ["derive"] }
 serde_cbor = "0.11.1"

src/ext.rs

@@ -105,3 +105,73 @@ pub fn alloc_local_with_default<T: Default, U>(sz: usize, within: impl FnOnce(&m
 	stackalloc::stackalloc_with_default(sz, within)
     }
 }
+
+/// Create a blanket-implementing trait that is a subtrait of any number of traits.
+///
+/// # Usage
+/// To subtype a trait with `Sized` types only:
+/// ```
+/// # use rsh::subtrait;
+/// subtrait!(pub SizedUnpinAsyncRead; "This subtrait must be sized": std::marker::Unpin + tokio::io::AsyncRead);
+/// ```
+/// To impl the trait for unsized types as well:
+/// ```
+/// # use rsh::subtrait;
+/// subtrait!(pub dyn UnsizedUnpinAsyncRead; "Subtraits `Unpin` and `AsyncRead`. Also implemented for unsized types.": std::marker::Unpin + tokio::io::AsyncRead);
+/// ```
+/// # Downcastable subtrait
+/// To create a subtrait that can be downcasted (correctly coerces to `dyn Any`), use the `virtual` keyword.
+/// ```
+/// # use rsh::subtrait;
+/// subtrait!(pub virtual DowncastableUnpinAsyncRead; "Subtraits `Unpin` and `AsyncRead`. Also dynamically downcastable": std::marker::Unpin + tokio::io::AsyncRead);
+/// subtrait!(pub virtual AnotherAny; "A dynamically downcastable trait that subtraits nothing else but `Any`");
+/// ```
+#[macro_export] macro_rules! subtrait {
+    (@ $v:vis $name:ident $(; $doc:literal)?: $($t:path),+) => {
+	$(#[doc = $doc])?
+	    $v trait $name: $($t+)+ {}
+    };
+    ($v:vis $name:ident $(; $doc:literal)?: $($t:path),+) => {
+	$crate::subtrait!(@ $v $name $(; $doc)?: Sized, $($t),+);
+	impl<T: $($t+)+> $name for T{}
+    };
+    ($v:vis dyn $name:ident $(; $doc:literal)?: $($t:path),+) => {
+	$crate::subtrait!(@ $v $name $(; $doc)?: $($t),+);
+	impl<T: ?Sized + $($t+)+> $name for T{}
+    };
+    ($v:vis virtual $name:ident $(; $doc:literal)?$(: $($t:path),*)?) => {
+	$crate::subtrait!(@ $v $name $(; $doc)?: ::mopa::Any $(, $($t),*)?);
+	const _:() = {
+	    fn _assert_object_safe(_: &dyn $name){}
+	};
+	mopafy!($name);
+	impl<T: ?Sized + ::mopa::Any $(+ $($t+)+)?> $name for T {}
+    };
+}
+
+// Static testing of `subtrait`
+const _:() = {
+    use mopa::*;
+    subtrait!(dyn Test; "test dynamic subtrait": std::marker::Unpin);
+    subtrait!(virtual TestAny; "test downcastable subtrait of `Read` and `Write`": std::io::Read);
+    subtrait!(virtual TestAny2; "test downcastable subtrait of only `Any`");
+    const fn _a<T: Test+?Sized>(){}
+    const fn _b<T: TestAny+?Sized>(){}
+    fn _c(a: Box<dyn TestAny>)
+    {
+	if a.is::<std::io::Stdin>() {
+	    let _ref: &std::io::Stdin = a.downcast_ref::<std::io::Stdin>().unwrap();
+	    drop(_ref);
+	    let _unbox: std::io::Stdin = *a.downcast().map_err(|_| ()).unwrap();
+	}
+    }
+    fn _d(a: &dyn TestAny)
+    {
+	if a.is::<std::io::Stdin>() {
+	    let _ref: &std::io::Stdin = a.downcast_ref::<std::io::Stdin>().unwrap();
+	}
+    }
+
+    const _TEST: () = _a::<dyn Test>();
+    const _TEST2: () = _b::<dyn TestAny>();
+};

src/sock.rs

@@ -9,8 +9,10 @@ use tokio::task::JoinHandle;
 use futures::Future;
 use cancel::*;
 
-/// Handles a raw socket
-pub fn handle_socket_with_shutdown<R, W, C: cancel::CancelFuture + 'static + Send>(sock_read: R, sock_write: W, shutdown: C) -> JoinHandle<eyre::Result<()>>
+
+
+/// Handles a raw, opened socket
+pub fn handle_socket_with_shutdown<R, W, C: cancel::CancelFuture + 'static + Send>(tx: W, rx: R, shutdown: C) -> JoinHandle<eyre::Result<()>>
 where R: AsyncRead + Unpin + Send + 'static,
       W: AsyncWrite + Unpin + Send + 'static
 {