WIP: aquatic_ws: add half-crappy load test, fix infinite loop bug

aquatic_ws_protocol/src/serde_helpers.rs

@@ -0,0 +1,247 @@
+use serde::{Serializer, Deserializer, de::{Visitor, SeqAccess}};
+
+use super::InfoHash;
+
+
+pub fn serialize_20_bytes<S>(
+    data: &[u8; 20],
+    serializer: S
+) -> Result<S::Ok, S::Error> where S: Serializer {
+    let text: String = data.iter().map(|byte| *byte as char).collect();
+
+    serializer.serialize_str(&text)
+}
+
+
+struct TwentyByteVisitor;
+
+impl<'de> Visitor<'de> for TwentyByteVisitor {
+    type Value = [u8; 20];
+
+    fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+        formatter.write_str("string consisting of 20 bytes")
+    }
+
+    #[inline]
+    fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
+        where E: ::serde::de::Error,
+    {
+        // Value is encoded in nodejs reference client something as follows:
+        // ```
+        // var infoHash = 'abcd..'; // 40 hexadecimals
+        // Buffer.from(infoHash, 'hex').toString('binary');
+        // ```
+        // As I understand it:
+        // - the code above produces a UTF16 string of 20 chars, each having
+        //   only the "low byte" set (e.g., numeric value ranges from 0-255)
+        // - serde_json decodes this to string of 20 chars (tested), each in
+        //   the aforementioned range (tested), so the bytes can be extracted
+        //   by casting each char to u8.
+
+        let mut arr = [0u8; 20];
+        let mut char_iter = value.chars();
+
+        for a in arr.iter_mut(){
+            if let Some(c) = char_iter.next(){
+                if c as u32 > 255 {
+                    return Err(E::custom(format!(
+                        "character not in single byte range: {:#?}",
+                        c
+                    )));
+                }
+
+                *a = c as u8;
+            } else {
+                return Err(E::custom(format!("not 20 bytes: {:#?}", value)));
+            }
+        }
+
+        Ok(arr)
+    }
+}
+
+
+#[inline]
+pub fn deserialize_20_bytes<'de, D>(
+    deserializer: D
+) -> Result<[u8; 20], D::Error>
+    where D: Deserializer<'de>
+{
+    deserializer.deserialize_any(TwentyByteVisitor)
+}
+
+
+pub struct InfoHashVecVisitor;
+
+
+impl<'de> Visitor<'de> for InfoHashVecVisitor {
+    type Value = Vec<InfoHash>;
+
+    fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+        formatter.write_str("string or array of strings consisting of 20 bytes")
+    }
+
+    #[inline]
+    fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
+        where E: ::serde::de::Error,
+    {
+        match TwentyByteVisitor::visit_str::<E>(TwentyByteVisitor, value){
+            Ok(arr) => Ok(vec![InfoHash(arr)]),
+            Err(err) => Err(E::custom(format!("got string, but {}", err)))
+        }
+    }
+
+    #[inline]
+    fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
+        where A: SeqAccess<'de>
+    {
+        let mut info_hashes: Self::Value = Vec::new();
+
+        while let Ok(Some(value)) = seq.next_element::<&str>(){
+            let arr = TwentyByteVisitor::visit_str(
+                TwentyByteVisitor, value
+            )?;
+
+            info_hashes.push(InfoHash(arr));
+        }
+
+        Ok(info_hashes)
+    }
+
+    #[inline]
+    fn visit_none<E>(self) -> Result<Self::Value, E>
+        where E: ::serde::de::Error
+    {
+        Ok(vec![])
+    }
+}
+
+
+/// Empty vector is returned if value is null or any invalid info hash
+/// is present
+#[inline]
+pub fn deserialize_info_hashes<'de, D>(
+    deserializer: D
+) -> Result<Vec<InfoHash>, D::Error>
+    where D: Deserializer<'de>,
+{
+    Ok(deserializer.deserialize_any(InfoHashVecVisitor).unwrap_or_default())
+}
+
+
+#[cfg(test)]
+mod tests {
+    use serde::Deserialize;
+
+    use super::*;
+
+    fn info_hash_from_bytes(bytes: &[u8]) -> InfoHash {
+        let mut arr = [0u8; 20];
+
+        assert!(bytes.len() == 20);
+
+        arr.copy_from_slice(&bytes[..]);
+
+        InfoHash(arr)
+    }
+
+    #[test]
+    fn test_deserialize_20_bytes(){
+        let input = r#""aaaabbbbccccddddeeee""#;
+
+        let expected = info_hash_from_bytes(b"aaaabbbbccccddddeeee");
+        let observed: InfoHash = serde_json::from_str(input).unwrap();
+
+        assert_eq!(observed, expected);
+
+        let input = r#""aaaabbbbccccddddeee""#;
+        let res_info_hash: Result<InfoHash, _> = serde_json::from_str(input);
+
+        assert!(res_info_hash.is_err());
+
+        let input = r#""aaaabbbbccccddddeee𝕊""#;
+        let res_info_hash: Result<InfoHash, _> = serde_json::from_str(input);
+
+        assert!(res_info_hash.is_err());
+    }
+
+    #[test]
+    fn test_serde_20_bytes(){
+        let info_hash = info_hash_from_bytes(b"aaaabbbbccccddddeeee");
+
+        let out = serde_json::to_string(&info_hash).unwrap();
+        let info_hash_2 = serde_json::from_str(&out).unwrap();
+
+        assert_eq!(info_hash, info_hash_2);
+    }
+
+    #[derive(Debug, PartialEq, Eq, Deserialize)]
+    struct Test {
+        #[serde(deserialize_with = "deserialize_info_hashes", default)]
+        info_hashes: Vec<InfoHash>,
+    }
+
+
+    #[test]
+    fn test_deserialize_info_hashes_vec(){
+        let input = r#"{
+            "info_hashes": ["aaaabbbbccccddddeeee", "aaaabbbbccccddddeeee"]
+        }"#;
+
+        let expected = Test {
+            info_hashes: vec![
+                info_hash_from_bytes(b"aaaabbbbccccddddeeee"),
+                info_hash_from_bytes(b"aaaabbbbccccddddeeee"),
+            ]
+        };
+
+        let observed: Test = serde_json::from_str(input).unwrap();
+
+        assert_eq!(observed, expected);
+    }
+
+    #[test]
+    fn test_deserialize_info_hashes_str(){
+        let input = r#"{
+            "info_hashes": "aaaabbbbccccddddeeee"
+        }"#;
+
+        let expected = Test {
+            info_hashes: vec![
+                info_hash_from_bytes(b"aaaabbbbccccddddeeee"),
+            ]
+        };
+
+        let observed: Test = serde_json::from_str(input).unwrap();
+
+        assert_eq!(observed, expected);
+    }
+
+    #[test]
+    fn test_deserialize_info_hashes_null(){
+        let input = r#"{
+            "info_hashes": null
+        }"#;
+
+        let expected = Test {
+            info_hashes: vec![]
+        };
+
+        let observed: Test = serde_json::from_str(input).unwrap();
+
+        assert_eq!(observed, expected);
+    }
+
+    #[test]
+    fn test_deserialize_info_hashes_missing(){
+        let input = r#"{}"#;
+
+        let expected = Test {
+            info_hashes: vec![]
+        };
+
+        let observed: Test = serde_json::from_str(input).unwrap();
+
+        assert_eq!(observed, expected);
+    }
+}