1 files changed, 62 insertions, 0 deletions
diff --git a/third_party/rust/slab/src/serde.rs b/third_party/rust/slab/src/serde.rs
new file mode 100644
index 0000000000..894d59c119
--- /dev/null
+++ b/third_party/rust/slab/src/serde.rs
@@ -0,0 +1,62 @@
+use core::fmt;
+use core::marker::PhantomData;
+
+use serde::de::{Deserialize, Deserializer, MapAccess, Visitor};
+use serde::ser::{Serialize, SerializeMap, Serializer};
+
+use super::{builder::Builder, Slab};
+
+impl<T> Serialize for Slab<T>
+where
+    T: Serialize,
+{
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        let mut map_serializer = serializer.serialize_map(Some(self.len()))?;
+        for (key, value) in self {
+            map_serializer.serialize_key(&key)?;
+            map_serializer.serialize_value(value)?;
+        }
+        map_serializer.end()
+    }
+}
+
+struct SlabVisitor<T>(PhantomData<T>);
+
+impl<'de, T> Visitor<'de> for SlabVisitor<T>
+where
+    T: Deserialize<'de>,
+{
+    type Value = Slab<T>;
+
+    fn expecting(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(fmt, "a map")
+    }
+
+    fn visit_map<A>(self, mut map: A) -> Result<Self::Value, A::Error>
+    where
+        A: MapAccess<'de>,
+    {
+        let mut builder = Builder::with_capacity(map.size_hint().unwrap_or(0));
+
+        while let Some((key, value)) = map.next_entry()? {
+            builder.pair(key, value)
+        }
+
+        Ok(builder.build())
+    }
+}
+
+impl<'de, T> Deserialize<'de> for Slab<T>
+where
+    T: Deserialize<'de>,
+{
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        deserializer.deserialize_map(SlabVisitor(PhantomData))
+    }
+}