fix decode array (#8)

Author: estin

src/codec.rs

@@ -603,15 +603,64 @@ fn decode_bytes(buf: &mut BytesMut, idx: usize) -> DecodeResult {
     }
 }
 
+fn is_array_ready_to_decode(
+    buf: &mut BytesMut,
+    idx: usize,
+    array_size: usize,
+) -> Result<(bool, usize), Error> {
+    let mut items: usize = 0;
+    let mut pos = idx;
+
+    // counting beginning of array items in buffer by `\r\n<type>`
+    loop {
+        let Some(new_pos) = buf[pos..].windows(2).position(|w| w.starts_with(b"\r\n")) else {
+            break;
+        };
+
+        if pos + new_pos + 2 >= buf.len() {
+            break;
+        }
+        pos += new_pos + 2;
+
+        items += match &buf[pos] {
+            // check nested array and calc it as item
+            b'*' => match decode_length(buf, pos) {
+                Ok(Some((_, -1))) => 1,
+                Ok(Some((p, size))) if size >= 0 => {
+                    let (ready, end_of_scan) = is_array_ready_to_decode(buf, p, size as usize)?;
+                    // nested array isn't ready
+                    if !ready {
+                        return Ok((false, end_of_scan));
+                    }
+                    pos = end_of_scan;
+                    1
+                }
+                Ok(Some((_, size))) => {
+                    return Err(Error::Parse(format!("Invalid array size: {}", size)))
+                }
+                _ => 0,
+            },
+            // array item found
+            b'$' | b':' | b'+' | b'-' => 1,
+            _ => 0,
+        };
+
+        if array_size <= items {
+            return Ok((true, pos));
+        }
+    }
+
+    Ok((array_size <= items, pos))
+}
+
 fn decode_array(buf: &mut BytesMut, idx: usize) -> DecodeResult {
     match decode_length(buf, idx)? {
         Some((pos, -1)) => Ok(Some((pos, Response::Nil))),
         Some((pos, size)) if size >= 0 => {
             let size = size as usize;
 
-            // ensure all array items present in buffer
-            let items = buf[idx..].windows(2).filter(|w| w == b"\r\n").count() / 2;
-            if items < size {
+            let (is_ready, _) = is_array_ready_to_decode(buf, idx, size)?;
+            if !is_ready {
                 return Ok(None);
             }
 
@@ -767,6 +816,43 @@ mod tests {
 
         let deserialized = codec.decode(&mut bytes).unwrap().unwrap();
         assert_eq!(deserialized, resp);
+
+        // $ echo -e "mget key1 key2\r\nquit" | curl -s telnet://localhost:6379 | python -c "import sys; print(repr(sys.stdin.read()))"
+        // '*2\r\n$-1\r\n$-1\r\n+OK\r\n'
+        let mut bytes = BytesMut::copy_from_slice(b"*2\r\n$-1\r\n$-1\r\n");
+        let result = codec.decode(&mut bytes).unwrap();
+
+        assert_eq!(
+            result,
+            Some(Response::Array(vec![Response::Nil, Response::Nil]))
+        );
+
+        // uncomplete nested array data
+        // [[['a']]]
+        // $ echo -e 'eval "return {{{\'a\'}}}" 0\r\nquit' | curl -s telnet://localhost:6379 | python -c "import sys; print(repr(sys.stdin.read()))"
+        // '*1\r\n*1\r\n*1\r\n$1\r\na\r\n+OK\r\n'
+        let mut bytes = BytesMut::copy_from_slice(b"*1\r\n*1\r\n*1\r\n");
+        let result = codec.decode(&mut bytes).unwrap();
+        assert_eq!(result, None);
+
+        // receiving remain parts
+        bytes.extend_from_slice(b"$1\r\na");
+        let result = codec.decode(&mut bytes).unwrap();
+        assert_eq!(result, None);
+
+        bytes.extend_from_slice(b"\r");
+        let result = codec.decode(&mut bytes).unwrap();
+        assert_eq!(result, None);
+
+        bytes.extend_from_slice(b"\n");
+        let result = codec.decode(&mut bytes).unwrap();
+
+        assert_eq!(
+            result,
+            Some(Response::Array(vec![Response::Array(vec![
+                Response::Array(vec![Response::Bytes(Bytes::from_static(b"a"))])
+            ])]))
+        );
     }
 
     #[test]

src/lib.rs

@@ -17,7 +17,7 @@
 //!     let key = gen_random_key();
 //!
 //!     // create list with one value
-//!     redis.exec(cmd::LPush(&key, "value"));
+//!     redis.exec(cmd::LPush(&key, "value")).await?;
 //!
 //!     // get value by index
 //!     let value = redis.exec(cmd::LIndex(&key, 0)).await?;