initial commit

exercises/08_futures/07_cancellation/Cargo.toml

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+[package]
+name = "cancellation"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+tokio = { version = "1", features = ["full"] }

exercises/08_futures/07_cancellation/src/lib.rs

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+// TODO: fix the `assert_eq` at the end of the tests.
+//  Do you understand why that's the resulting output?
+use std::time::Duration;
+use tokio::io::AsyncReadExt;
+use tokio::net::TcpListener;
+
+pub async fn run(listener: TcpListener, n_messages: usize, timeout: Duration) -> Vec<u8> {
+    let mut buffer = Vec::new();
+    for _ in 0..n_messages {
+        let (mut stream, _) = listener.accept().await.unwrap();
+        let _ = tokio::time::timeout(timeout, async {
+            stream.read_to_end(&mut buffer).await.unwrap();
+        })
+        .await;
+    }
+    buffer
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use tokio::io::AsyncWriteExt;
+
+    #[tokio::test]
+    async fn ping() {
+        let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
+        let addr = listener.local_addr().unwrap();
+        let messages = vec!["hello", "from", "this", "task"];
+        let timeout = Duration::from_millis(20);
+        let handle = tokio::spawn(run(listener, messages.len(), timeout.clone()));
+
+        for message in messages {
+            let mut socket = tokio::net::TcpStream::connect(addr).await.unwrap();
+            let (_, mut writer) = socket.split();
+
+            let (beginning, end) = message.split_at(message.len() / 2);
+
+            // Send first half
+            writer.write_all(beginning.as_bytes()).await.unwrap();
+            tokio::time::sleep(timeout * 2).await;
+            writer.write_all(end.as_bytes()).await.unwrap();
+
+            // Close the write side of the socket
+            let _ = writer.shutdown().await;
+        }
+
+        let buffered = handle.await.unwrap();
+        let buffered = std::str::from_utf8(&buffered).unwrap();
+        assert_eq!(buffered, "");
+    }
+}