1 files changed, 122 insertions, 0 deletions
diff --git a/third_party/rust/indexmap/src/borsh.rs b/third_party/rust/indexmap/src/borsh.rs
new file mode 100644
index 0000000000..c485bd5222
--- /dev/null
+++ b/third_party/rust/indexmap/src/borsh.rs
@@ -0,0 +1,122 @@
+#![cfg_attr(docsrs, doc(cfg(feature = "borsh")))]
+
+use alloc::vec::Vec;
+use core::hash::BuildHasher;
+use core::hash::Hash;
+use core::mem::size_of;
+
+use borsh::error::ERROR_ZST_FORBIDDEN;
+use borsh::io::{Error, ErrorKind, Read, Result, Write};
+use borsh::{BorshDeserialize, BorshSerialize};
+
+use crate::map::IndexMap;
+use crate::set::IndexSet;
+
+impl<K, V, S> BorshSerialize for IndexMap<K, V, S>
+where
+    K: BorshSerialize,
+    V: BorshSerialize,
+{
+    #[inline]
+    fn serialize<W: Write>(&self, writer: &mut W) -> Result<()> {
+        check_zst::<K>()?;
+
+        let iterator = self.iter();
+
+        u32::try_from(iterator.len())
+            .map_err(|_| ErrorKind::InvalidData)?
+            .serialize(writer)?;
+
+        for (key, value) in iterator {
+            key.serialize(writer)?;
+            value.serialize(writer)?;
+        }
+
+        Ok(())
+    }
+}
+
+impl<K, V, S> BorshDeserialize for IndexMap<K, V, S>
+where
+    K: BorshDeserialize + Eq + Hash,
+    V: BorshDeserialize,
+    S: BuildHasher + Default,
+{
+    #[inline]
+    fn deserialize_reader<R: Read>(reader: &mut R) -> Result<Self> {
+        check_zst::<K>()?;
+        let vec = <Vec<(K, V)>>::deserialize_reader(reader)?;
+        Ok(vec.into_iter().collect::<IndexMap<K, V, S>>())
+    }
+}
+
+impl<T, S> BorshSerialize for IndexSet<T, S>
+where
+    T: BorshSerialize,
+{
+    #[inline]
+    fn serialize<W: Write>(&self, writer: &mut W) -> Result<()> {
+        check_zst::<T>()?;
+
+        let iterator = self.iter();
+
+        u32::try_from(iterator.len())
+            .map_err(|_| ErrorKind::InvalidData)?
+            .serialize(writer)?;
+
+        for item in iterator {
+            item.serialize(writer)?;
+        }
+
+        Ok(())
+    }
+}
+
+impl<T, S> BorshDeserialize for IndexSet<T, S>
+where
+    T: BorshDeserialize + Eq + Hash,
+    S: BuildHasher + Default,
+{
+    #[inline]
+    fn deserialize_reader<R: Read>(reader: &mut R) -> Result<Self> {
+        check_zst::<T>()?;
+        let vec = <Vec<T>>::deserialize_reader(reader)?;
+        Ok(vec.into_iter().collect::<IndexSet<T, S>>())
+    }
+}
+
+fn check_zst<T>() -> Result<()> {
+    if size_of::<T>() == 0 {
+        return Err(Error::new(ErrorKind::InvalidData, ERROR_ZST_FORBIDDEN));
+    }
+    Ok(())
+}
+
+#[cfg(test)]
+mod borsh_tests {
+    use super::*;
+
+    #[test]
+    fn map_borsh_roundtrip() {
+        let original_map: IndexMap<i32, i32> = {
+            let mut map = IndexMap::new();
+            map.insert(1, 2);
+            map.insert(3, 4);
+            map.insert(5, 6);
+            map
+        };
+        let serialized_map = borsh::to_vec(&original_map).unwrap();
+        let deserialized_map: IndexMap<i32, i32> =
+            BorshDeserialize::try_from_slice(&serialized_map).unwrap();
+        assert_eq!(original_map, deserialized_map);
+    }
+
+    #[test]
+    fn set_borsh_roundtrip() {
+        let original_map: IndexSet<i32> = [1, 2, 3, 4, 5, 6].into_iter().collect();
+        let serialized_map = borsh::to_vec(&original_map).unwrap();
+        let deserialized_map: IndexSet<i32> =
+            BorshDeserialize::try_from_slice(&serialized_map).unwrap();
+        assert_eq!(original_map, deserialized_map);
+    }
+}