Removed clone requirement in Struct -> RecordBatch. (#307)

src/array/struct_.rs

@@ -52,6 +52,20 @@ impl StructArray {
         }
     }
 
+    pub fn into_data(self) -> (Vec<Field>, Vec<Arc<dyn Array>>, Option<Bitmap>) {
+        let Self {
+            data_type,
+            values,
+            validity,
+        } = self;
+        let fields = if let DataType::Struct(fields) = data_type {
+            fields
+        } else {
+            unreachable!()
+        };
+        (fields, values, validity)
+    }
+
     pub fn slice(&self, offset: usize, length: usize) -> Self {
         let validity = self.validity.clone().map(|x| x.slice(offset, length));
         Self {

src/record_batch.rs

@@ -339,17 +339,14 @@ impl Default for RecordBatchOptions {
     }
 }
 
-impl From<&StructArray> for RecordBatch {
-    /// Create a record batch from struct array.
-    ///
-    /// This currently does not flatten and nested struct types
-    fn from(struct_array: &StructArray) -> Self {
-        if let DataType::Struct(fields) = struct_array.data_type() {
-            let schema = Arc::new(Schema::new(fields.clone()));
-            let columns = struct_array.values().to_vec();
-            RecordBatch { schema, columns }
-        } else {
-            unreachable!("unable to get datatype as struct")
+impl From<StructArray> for RecordBatch {
+    /// # Panics iff the null count of the array is not null.
+    fn from(array: StructArray) -> Self {
+        assert!(array.null_count() == 0);
+        let (fields, values, _) = array.into_data();
+        RecordBatch {
+            schema: Arc::new(Schema::new(fields)),
+            columns: values,
         }
     }
 }

tests/it/record_batch.rs

@@ -91,22 +91,18 @@ fn number_of_fields_mismatch() {
 fn from_struct_array() {
     let boolean = Arc::new(BooleanArray::from_slice(&[false, false, true, true])) as ArrayRef;
     let int = Arc::new(Int32Array::from_slice(&[42, 28, 19, 31])) as ArrayRef;
-    let struct_array = StructArray::from_data(
-        vec![
-            Field::new("b", DataType::Boolean, false),
-            Field::new("c", DataType::Int32, false),
-        ],
-        vec![boolean.clone(), int.clone()],
-        None,
-    );
 
-    let batch = RecordBatch::from(&struct_array);
+    let fields = vec![
+        Field::new("b", DataType::Boolean, false),
+        Field::new("c", DataType::Int32, false),
+    ];
+
+    let array = StructArray::from_data(fields.clone(), vec![boolean.clone(), int.clone()], None);
+
+    let batch = RecordBatch::from(array);
     assert_eq!(2, batch.num_columns());
     assert_eq!(4, batch.num_rows());
-    assert_eq!(
-        struct_array.data_type(),
-        &DataType::Struct(batch.schema().fields().to_vec())
-    );
+    assert_eq!(&fields, batch.schema().fields());
     assert_eq!(boolean.as_ref(), batch.column(0).as_ref());
     assert_eq!(int.as_ref(), batch.column(1).as_ref());
 }