RUST-1175 Support zero-copy deserialization from cursors (#579)

Author: patrickfreed

src/bson_util/mod.rs

@@ -42,15 +42,6 @@ pub(crate) fn get_u64(val: &Bson) -> Option<u64> {
     }
 }
 
-pub(crate) fn get_u64_raw(val: RawBsonRef<'_>) -> Option<u64> {
-    match val {
-        RawBsonRef::Int32(i) => get_u64(&Bson::Int32(i)),
-        RawBsonRef::Int64(i) => get_u64(&Bson::Int64(i)),
-        RawBsonRef::Double(i) => get_u64(&Bson::Double(i)),
-        _ => None,
-    }
-}
-
 pub(crate) fn to_bson_array(docs: &[Document]) -> Bson {
     Bson::Array(docs.iter().map(|doc| Bson::Document(doc.clone())).collect())
 }

src/client/executor.rs

@@ -148,7 +148,6 @@ impl Client {
     pub(crate) async fn execute_cursor_operation<Op, T>(&self, op: Op) -> Result<Cursor<T>>
     where
         Op: Operation<O = CursorSpecification>,
-        T: DeserializeOwned + Unpin + Send + Sync,
     {
         Box::pin(async {
             let mut details = self.execute_operation_with_details(op, None).await?;
@@ -173,7 +172,6 @@ impl Client {
     ) -> Result<SessionCursor<T>>
     where
         Op: Operation<O = CursorSpecification>,
-        T: DeserializeOwned + Unpin + Send + Sync,
     {
         let mut details = self
             .execute_operation_with_details(op, &mut *session)

src/coll/mod.rs

@@ -849,12 +849,7 @@ impl<T> Collection<T> {
             .execute_watch_with_session(pipeline, options, target, None, session)
             .await
     }
-}
 
-impl<T> Collection<T>
-where
-    T: DeserializeOwned + Unpin + Send + Sync,
-{
     /// Finds the documents in the collection matching `filter`.
     pub async fn find(
         &self,
@@ -886,7 +881,12 @@ where
 
         client.execute_session_cursor_operation(find, session).await
     }
+}
 
+impl<T> Collection<T>
+where
+    T: DeserializeOwned + Unpin + Send + Sync,
+{
     /// Finds a single document in the collection matching `filter`.
     pub async fn find_one(
         &self,