primitives - BalancesMap - key to lowercase on Serialization

Author: elpiel

primitives/src/balances_map.rs

@@ -1,5 +1,60 @@
 use std::collections::BTreeMap;
 
 use crate::BigNum;
+use std::collections::btree_map::{Entry, Iter, Values};
 
-pub type BalancesMap = BTreeMap<String, BigNum>;
+use serde::{ser::SerializeMap, Deserialize, Serialize, Serializer};
+use std::iter::FromIterator;
+
+type BalancesKey = String;
+type BalancesValue = BigNum;
+
+#[serde(transparent)]
+#[derive(Clone, Debug, Deserialize, Default)]
+pub struct BalancesMap(
+    #[serde(serialize_with = "serialize_balances_map")] BTreeMap<BalancesKey, BalancesValue>,
+);
+
+impl BalancesMap {
+    pub fn iter(&self) -> Iter<'_, BalancesKey, BalancesValue> {
+        self.0.iter()
+    }
+
+    pub fn values(&self) -> Values<'_, BalancesKey, BalancesValue> {
+        self.0.values()
+    }
+
+    pub fn get(&self, key: &BalancesKey) -> Option<&BalancesValue> {
+        self.0.get(key)
+    }
+
+    pub fn entry(&mut self, key: BalancesKey) -> Entry<'_, BalancesKey, BalancesValue> {
+        self.0.entry(key)
+    }
+
+    pub fn insert(&mut self, key: BalancesKey, value: BalancesValue) -> Option<BalancesValue> {
+        self.0.insert(key, value)
+    }
+}
+
+impl FromIterator<(BalancesKey, BalancesValue)> for BalancesMap {
+    fn from_iter<I: IntoIterator<Item = (BalancesKey, BalancesValue)>>(iter: I) -> Self {
+        // @TODO: Is there better way to do this?
+        let btree_map: BTreeMap<BalancesKey, BalancesValue> = iter.into_iter().collect();
+
+        BalancesMap(btree_map)
+    }
+}
+
+impl Serialize for BalancesMap {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        let mut map = serializer.serialize_map(Some(self.0.len()))?;
+        for (key, big_num) in self.0.iter() {
+            map.serialize_entry(&key.to_lowercase(), big_num)?;
+        }
+        map.end()
+    }
+}