Fix negative nonces failing to deserialize

Negative message nonces caused deserialization errors, as serde would
not deserialize integers into strings.

To fix this, change `Message::nonce` into an `Option<Snowflake>` from an
`Option<String>`. This new `Snowflake` is a wrapper around an `i64`. Use
a new `I64Visitor` to deserialize i64s, u64s, and strs into the wanted
i64.

1 files changed, 31 insertions, 0 deletions

diff --git a/src/model/utils.rs b/src/model/utils.rs
index f88ecf5..6363fb6 100644
--- a/src/model/utils.rs
+++ b/src/model/utils.rs
@@ -240,3 +240,34 @@ impl<'de> Visitor<'de> for U64Visitor {
         Ok(v)
     }
 }
+
+pub struct I64Visitor;
+
+impl<'de> Visitor<'de> for I64Visitor {
+    type Value = i64;
+
+    fn expecting(&self, formatter: &mut Formatter) -> FmtResult {
+        formatter.write_str("identifier")
+    }
+
+    fn visit_str<E: DeError>(self, v: &str) -> StdResult<Self::Value, E> {
+        match v.parse::<i64>() {
+            Ok(v) => Ok(v),
+            Err(_) => {
+                let mut s = String::new();
+                s.push_str("Unknown i64 value: ");
+                s.push_str(v);
+
+                Err(DeError::custom(s))
+            },
+        }
+    }
+
+    fn visit_i64<E: DeError>(self, v: i64) -> StdResult<Self::Value, E> {
+        Ok(v)
+    }
+
+    fn visit_u64<E: DeError>(self, v: u64) -> StdResult<Self::Value, E> {
+        Ok(v as i64)
+    }
+}