[Feat] Split Daemon & TUI

iota-ipc/src/transport.rs

@@ -0,0 +1,59 @@
+use serde::Serialize;
+use serde::de::DeserializeOwned;
+use std::io::{Error, ErrorKind, Result};
+use tokio::io::{AsyncRead, AsyncReadExt, AsyncWrite, AsyncWriteExt};
+
+const MAX_MESSAGE_SIZE: usize = 1024 * 1024;
+
+/* Length-prefixing preserves message boundaries on a byte stream and bounds
+ * allocations before JSON is deserialized. */
+pub async fn write_msg<W, T>(writer: &mut W, message: &T) -> Result<()>
+where
+    W: AsyncWrite + Unpin,
+    T: Serialize,
+{
+    let payload =
+        serde_json::to_vec(message).map_err(|error| Error::new(ErrorKind::InvalidData, error))?;
+    let len = u32::try_from(payload.len())
+        .map_err(|_| Error::new(ErrorKind::InvalidData, "IPC message is too large"))?;
+    writer.write_u32(len).await?;
+    writer.write_all(&payload).await?;
+    writer.flush().await
+}
+
+pub async fn read_msg<R, T>(reader: &mut R) -> Result<T>
+where
+    R: AsyncRead + Unpin,
+    T: DeserializeOwned,
+{
+    let len = reader.read_u32().await? as usize;
+    if len > MAX_MESSAGE_SIZE {
+        return Err(Error::new(
+            ErrorKind::InvalidData,
+            "IPC message exceeds limit",
+        ));
+    }
+    let mut payload = vec![0; len];
+    reader.read_exact(&mut payload).await?;
+    serde_json::from_slice(&payload).map_err(|error| Error::new(ErrorKind::InvalidData, error))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{read_msg, write_msg};
+    use crate::protocol::ClientMessage;
+
+    #[tokio::test]
+    async fn round_trips_framed_messages() {
+        let (mut writer, mut reader) = tokio::io::duplex(1024);
+        let message = ClientMessage::Command {
+            seq: 4,
+            line: "help".into(),
+        };
+        write_msg(&mut writer, &message)
+            .await
+            .expect("write succeeds");
+        let received: ClientMessage = read_msg(&mut reader).await.expect("read succeeds");
+        assert!(matches!(received, ClientMessage::Command { seq: 4, line } if line == "help"));
+    }
+}