ifx

Signed-off-by: Joe Isaacs <joe.isaacs@live.co.uk>

Author: joseph-isaacs

vortex-array/src/arrays/struct_/array.rs

@@ -3,6 +3,7 @@
 
 use std::fmt::Debug;
 use std::iter::once;
+use std::mem::MaybeUninit;
 use std::sync::Arc;
 
 use vortex_error::VortexExpect;
@@ -156,7 +157,7 @@ pub struct StructArray {
 
 pub struct StructArrayParts {
     pub struct_fields: StructFields,
-    pub fields: Arc<[ArrayRef]>,
+    pub fields: Vec<ArrayRef>,
     pub validity: Validity,
 }
 
@@ -373,6 +374,32 @@ impl StructArray {
         Ok(())
     }
 
+    /// Constructs a new `StructArray` from a `Vec<ArrayRef>`, avoiding an intermediate
+    /// `Arc<[ArrayRef]>` allocation by building the slots directly from the vec.
+    pub fn try_new_from_vec(
+        names: FieldNames,
+        fields: Vec<ArrayRef>,
+        length: usize,
+        validity: Validity,
+    ) -> VortexResult<Self> {
+        let field_dtypes: Vec<_> = fields.iter().map(|d| d.dtype()).cloned().collect();
+        let dtype = StructFields::new(names, field_dtypes);
+
+        Self::validate(&fields, &dtype, length, &validity)?;
+
+        let validity_slot = validity_to_child(&validity, length);
+        let mut slots = Vec::with_capacity(1 + fields.len());
+        slots.push(validity_slot);
+        slots.extend(fields.into_iter().map(Some));
+
+        Ok(Self {
+            len: length,
+            dtype: DType::Struct(dtype, validity.nullability()),
+            slots,
+            stats_set: Default::default(),
+        })
+    }
+
     pub fn try_new_with_dtype(
         fields: impl Into<Arc<[ArrayRef]>>,
         dtype: StructFields,
@@ -389,7 +416,7 @@ impl StructArray {
     pub fn into_parts(self) -> StructArrayParts {
         let validity = self.validity();
         let struct_fields = self.dtype.into_struct_fields();
-        let fields: Arc<[ArrayRef]> = self
+        let fields: Vec<ArrayRef> = self
             .slots
             .into_iter()
             .skip(FIELDS_OFFSET)

vortex-layout/src/layouts/partitioned.rs

@@ -116,7 +116,7 @@ impl<P: Send + Sync + 'static> PartitionedExprEval<P> for PartitionedExpr<P> {
             let field_arrays = try_join_all(field_evals);
             let (field_arrays, mask) = try_join!(field_arrays, mask)?;
 
-            let root_scope = StructArray::try_new(
+            let root_scope = StructArray::try_new_from_vec(
                 self.partition_names.clone(),
                 field_arrays,
                 mask.true_count(),

vortex-layout/src/layouts/struct_/reader.rs

@@ -366,7 +366,7 @@ impl LayoutReader for StructReader {
                         .map(|a| a.clone().mask(validity.clone()))
                         .try_collect()?;
 
-                    Ok(StructArray::try_new(
+                    Ok(StructArray::try_new_from_vec(
                         struct_array.names().clone(),
                         masked_fields,
                         struct_array.len(),