Make the serde and zerocopy meilidb-types dependencies optional

meilidb-types/src/lib.rs

@@ -1,24 +1,16 @@
-use serde::{Deserialize, Serialize};
+#[cfg(feature = "zerocopy")]
 use zerocopy::{AsBytes, FromBytes};
 
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
+
 /// Represent an internally generated document unique identifier.
 ///
 /// It is used to inform the database the document you want to deserialize.
 /// Helpful for custom ranking.
-#[derive(
-    Debug,
-    Copy,
-    Clone,
-    Eq,
-    PartialEq,
-    PartialOrd,
-    Ord,
-    Hash,
-    Serialize,
-    Deserialize,
-    AsBytes,
-    FromBytes,
-)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq, PartialOrd, Ord, Hash)]
+#[cfg_attr(feature = "zerocopy", derive(AsBytes, FromBytes))]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[repr(C)]
 pub struct DocumentId(pub u64);
 
@@ -27,7 +19,8 @@ pub struct DocumentId(pub u64);
 ///
 /// This is stored in the map, generated at index time,
 /// extracted and interpreted at search time.
-#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, AsBytes, FromBytes)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[cfg_attr(feature = "zerocopy", derive(AsBytes, FromBytes))]
 #[repr(C)]
 pub struct DocIndex {
     /// The document identifier where the word was found.