feat(eip4895): implement Withdrawals

crates/eips/src/eip4895.rs

@@ -2,6 +2,7 @@
 //!
 //! [EIP-4895]: https://eips.ethereum.org/EIPS/eip-4895
 
+use alloc::vec::Vec;
 use alloy_primitives::{Address, U256};
 use alloy_rlp::{RlpDecodable, RlpEncodable};
 
@@ -37,6 +38,63 @@ impl Withdrawal {
     }
 }
 
+/// Represents a collection of Withdrawals.
+#[derive(Clone, Debug, Default, PartialEq, Eq, Hash, RlpEncodable, RlpDecodable)]
+#[cfg_attr(any(test, feature = "arbitrary"), derive(arbitrary::Arbitrary))]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+pub struct Withdrawals(Vec<Withdrawal>);
+
+impl Withdrawals {
+    /// Create a new Withdrawals instance.
+    pub const fn new(withdrawals: Vec<Withdrawal>) -> Self {
+        Self(withdrawals)
+    }
+
+    /// Calculate the total size, including capacity, of the Withdrawals.
+    #[inline]
+    pub fn total_size(&self) -> usize {
+        self.0.capacity() * core::mem::size_of::<Withdrawal>()
+    }
+
+    /// Calculate a heuristic for the in-memory size of the [Withdrawals].
+    #[inline]
+    pub fn size(&self) -> usize {
+        self.0.len() * core::mem::size_of::<Withdrawal>()
+    }
+
+    /// Get an iterator over the Withdrawals.
+    pub fn iter(&self) -> core::slice::Iter<'_, Withdrawal> {
+        self.0.iter()
+    }
+
+    /// Get a mutable iterator over the Withdrawals.
+    pub fn iter_mut(&mut self) -> core::slice::IterMut<'_, Withdrawal> {
+        self.0.iter_mut()
+    }
+
+    /// Convert [Self] into raw vec of withdrawals.
+    pub fn into_inner(self) -> Vec<Withdrawal> {
+        self.0
+    }
+}
+
+impl<'a> IntoIterator for &'a Withdrawals {
+    type Item = &'a Withdrawal;
+    type IntoIter = core::slice::Iter<'a, Withdrawal>;
+    fn into_iter(self) -> Self::IntoIter {
+        self.iter()
+    }
+}
+
+impl<'a> IntoIterator for &'a mut Withdrawals {
+    type Item = &'a mut Withdrawal;
+    type IntoIter = core::slice::IterMut<'a, Withdrawal>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.iter_mut()
+    }
+}
+
 #[cfg(all(test, feature = "serde"))]
 mod tests {
     use super::*;
@@ -46,8 +104,14 @@ mod tests {
     fn test_withdrawal_serde_roundtrip() {
         let input = r#"[{"index":"0x0","validatorIndex":"0x0","address":"0x0000000000000000000000000000000000001000","amount":"0x1"},{"index":"0x1","validatorIndex":"0x1","address":"0x0000000000000000000000000000000000001001","amount":"0x1"},{"index":"0x2","validatorIndex":"0x2","address":"0x0000000000000000000000000000000000001002","amount":"0x1"},{"index":"0x3","validatorIndex":"0x3","address":"0x0000000000000000000000000000000000001003","amount":"0x1"},{"index":"0x4","validatorIndex":"0x4","address":"0x0000000000000000000000000000000000001004","amount":"0x1"},{"index":"0x5","validatorIndex":"0x5","address":"0x0000000000000000000000000000000000001005","amount":"0x1"},{"index":"0x6","validatorIndex":"0x6","address":"0x0000000000000000000000000000000000001006","amount":"0x1"},{"index":"0x7","validatorIndex":"0x7","address":"0x0000000000000000000000000000000000001007","amount":"0x1"},{"index":"0x8","validatorIndex":"0x8","address":"0x0000000000000000000000000000000000001008","amount":"0x1"},{"index":"0x9","validatorIndex":"0x9","address":"0x0000000000000000000000000000000000001009","amount":"0x1"},{"index":"0xa","validatorIndex":"0xa","address":"0x000000000000000000000000000000000000100a","amount":"0x1"},{"index":"0xb","validatorIndex":"0xb","address":"0x000000000000000000000000000000000000100b","amount":"0x1"},{"index":"0xc","validatorIndex":"0xc","address":"0x000000000000000000000000000000000000100c","amount":"0x1"},{"index":"0xd","validatorIndex":"0xd","address":"0x000000000000000000000000000000000000100d","amount":"0x1"},{"index":"0xe","validatorIndex":"0xe","address":"0x000000000000000000000000000000000000100e","amount":"0x1"},{"index":"0xf","validatorIndex":"0xf","address":"0x000000000000000000000000000000000000100f","amount":"0x1"}]"#;
 
+        // With a vector of withdrawals.
         let withdrawals: Vec<Withdrawal> = serde_json::from_str(input).unwrap();
         let s = serde_json::to_string(&withdrawals).unwrap();
         assert_eq!(input, s);
+
+        // With a Withdrawals struct.
+        let withdrawals: Withdrawals = serde_json::from_str(input).unwrap();
+        let s = serde_json::to_string(&withdrawals).unwrap();
+        assert_eq!(input, s);
     }
 }