tokio: add AsyncBufReadExt::read_until

1 files changed, 56 insertions, 0 deletions

diff --git a/tokio/tests/io_read_until.rs b/tokio/tests/io_read_until.rs
new file mode 100644
index 00000000..22945f55
--- /dev/null
+++ b/tokio/tests/io_read_until.rs
@@ -0,0 +1,56 @@
+#![deny(warnings, rust_2018_idioms)]
+#![feature(async_await)]
+
+use tokio::io::{AsyncBufRead, AsyncBufReadExt, AsyncRead};
+use tokio_test::assert_ok;
+
+use std::io;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+
+#[tokio::test]
+async fn read_until() {
+    struct Rd {
+        val: &'static [u8],
+    }
+
+    impl AsyncRead for Rd {
+        fn poll_read(
+            self: Pin<&mut Self>,
+            _: &mut Context<'_>,
+            _: &mut [u8],
+        ) -> Poll<io::Result<usize>> {
+            unimplemented!()
+        }
+    }
+
+    impl AsyncBufRead for Rd {
+        fn poll_fill_buf<'a>(
+            self: Pin<&'a mut Self>,
+            _: &mut Context<'_>,
+        ) -> Poll<io::Result<&'a [u8]>> {
+            Poll::Ready(Ok(self.val))
+        }
+
+        fn consume(mut self: Pin<&mut Self>, amt: usize) {
+            self.val = &self.val[amt..];
+        }
+    }
+
+    let mut buf = vec![];
+    let mut rd = Rd {
+        val: b"hello world",
+    };
+
+    let n = assert_ok!(rd.read_until(b' ', &mut buf).await);
+    assert_eq!(n, 6);
+    assert_eq!(buf, b"hello ");
+    buf.clear();
+    let n = assert_ok!(rd.read_until(b' ', &mut buf).await);
+    assert_eq!(n, 5);
+    assert_eq!(buf, b"world");
+    buf.clear();
+    let n = assert_ok!(rd.read_until(b' ', &mut buf).await);
+    assert_eq!(n, 0);
+    assert_eq!(buf, []);
+}