feat: add tokio support for async decoding and optimize library functions with inline attributes

Author: panayang

Cargo.toml

@@ -54,6 +54,7 @@ serde = ["dep:serde"]
 zero-copy = ["bincode_derive-next?/zero-copy"]
 static-size = ["bincode_derive-next?/static-size"]
 async-fiber = ["dep:futures-io", "dep:libc", "std"]
+tokio = ["dep:tokio", "async-fiber"]
 # Remember to run 'MIRIFLAGS="-Zmiri-disable-isolation" cargo +nightly miri test --all-features --no-fail-fast'
 # And remeber 'sudo chrt -f 99 cargo +nightly bench --bench complex' also.
 # And for loom: 'RUSTFLAGS="--cfg loom" cargo test --test async_fiber_loom --features "async-fiber, tokio/full" --release'
@@ -67,6 +68,7 @@ pastey = "0.2"
 futures-io = { version = "0.3", optional = true }
 libc = { version = "0.2", optional = true }
 panic-halt = { version = "1.0", optional = true }
+tokio = { version = "1.50", default-features = false, optional = true }
 
 # Used for tests
 [dev-dependencies]

src/de/async_fiber.rs

@@ -1038,3 +1038,24 @@ impl<R, F, T> Drop for BridgeFuture<R, F, T> {
         }
     }
 }
+
+/// A lightweight adapter to use `tokio::io::AsyncRead` with `AsyncFiberBridge`.
+#[cfg(all(feature = "tokio", feature = "async-fiber"))]
+pub struct TokioReader<R>(pub R);
+
+#[cfg(all(feature = "tokio", feature = "async-fiber"))]
+impl<R: tokio::io::AsyncRead + Unpin> futures_io::AsyncRead for TokioReader<R> {
+    #[inline]
+    fn poll_read(
+        mut self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+        buf: &mut [u8],
+    ) -> Poll<std::io::Result<usize>> {
+        let mut read_buf = tokio::io::ReadBuf::new(buf);
+        match Pin::new(&mut self.0).poll_read(cx, &mut read_buf) {
+            | Poll::Ready(Ok(())) => Poll::Ready(Ok(read_buf.filled().len())),
+            | Poll::Ready(Err(e)) => Poll::Ready(Err(e)),
+            | Poll::Pending => Poll::Pending,
+        }
+    }
+}

src/features/serde/de_owned.rs

@@ -22,7 +22,7 @@ use crate::features::IoReader;
 
 /// Serde decoder encapsulating an owned reader.
 pub struct OwnedSerdeDecoder<DE: Decoder> {
-    pub(super) de: DE,
+    pub(crate) de: DE,
 }
 
 impl<DE: Decoder> OwnedSerdeDecoder<DE> {