DRI refactor

Author: alamb

datafusion/core/src/datasource/file_format/mod.rs

@@ -42,7 +42,7 @@ use crate::error::Result;
 use crate::execution::context::SessionState;
 use crate::physical_plan::{ExecutionPlan, Statistics};
 
-use arrow_schema::{DataType, Field, Schema};
+use arrow_schema::{DataType, Field, FieldRef, Schema};
 use datafusion_common::file_options::file_type::FileType;
 use datafusion_common::{internal_err, not_impl_err, GetExt};
 use datafusion_expr::Expr;
@@ -235,6 +235,12 @@ pub fn file_type_to_format(
     }
 }
 
+/// Create a new field with the specified data type, copying the other
+/// properties from the input field
+fn field_with_new_type(field: &FieldRef, new_type: DataType) -> FieldRef {
+    Arc::new(field.as_ref().clone().with_data_type(new_type))
+}
+
 /// Transform a schema to use view types for Utf8 and Binary
 ///
 /// See [parquet::ParquetFormat::force_view_types] for details
@@ -243,14 +249,12 @@ pub fn transform_schema_to_view(schema: &Schema) -> Schema {
         .fields
         .iter()
         .map(|field| match field.data_type() {
-            DataType::Utf8 | DataType::LargeUtf8 => Arc::new(
-                Field::new(field.name(), DataType::Utf8View, field.is_nullable())
-                    .with_metadata(field.metadata().to_owned()),
-            ),
-            DataType::Binary | DataType::LargeBinary => Arc::new(
-                Field::new(field.name(), DataType::BinaryView, field.is_nullable())
-                    .with_metadata(field.metadata().to_owned()),
-            ),
+            DataType::Utf8 | DataType::LargeUtf8 => {
+                field_with_new_type(field, DataType::Utf8View)
+            }
+            DataType::Binary | DataType::LargeBinary => {
+                field_with_new_type(field, DataType::BinaryView)
+            }
             _ => field.clone(),
         })
         .collect();
@@ -276,6 +280,7 @@ pub(crate) fn coerce_file_schema_to_view_type(
             (f.name(), dt)
         })
         .collect();
+
     if !transform {
         return None;
     }
@@ -285,14 +290,13 @@ pub(crate) fn coerce_file_schema_to_view_type(
         .iter()
         .map(
             |field| match (table_fields.get(field.name()), field.data_type()) {
-                (Some(DataType::Utf8View), DataType::Utf8)
-                | (Some(DataType::Utf8View), DataType::LargeUtf8) => Arc::new(
-                    Field::new(field.name(), DataType::Utf8View, field.is_nullable()),
-                ),
-                (Some(DataType::BinaryView), DataType::Binary)
-                | (Some(DataType::BinaryView), DataType::LargeBinary) => Arc::new(
-                    Field::new(field.name(), DataType::BinaryView, field.is_nullable()),
-                ),
+                (Some(DataType::Utf8View), DataType::Utf8 | DataType::LargeUtf8) => {
+                    field_with_new_type(field, DataType::Utf8View)
+                }
+                (
+                    Some(DataType::BinaryView),
+                    DataType::Binary | DataType::LargeBinary,
+                ) => field_with_new_type(field, DataType::BinaryView),
                 _ => field.clone(),
             },
         )
@@ -310,18 +314,9 @@ pub fn transform_binary_to_string(schema: &Schema) -> Schema {
         .fields
         .iter()
         .map(|field| match field.data_type() {
-            DataType::Binary => Arc::new(
-                Field::new(field.name(), DataType::Utf8, field.is_nullable())
-                    .with_metadata(field.metadata().to_owned()),
-            ),
-            DataType::LargeBinary => Arc::new(
-                Field::new(field.name(), DataType::LargeUtf8, field.is_nullable())
-                    .with_metadata(field.metadata().to_owned()),
-            ),
-            DataType::BinaryView => Arc::new(
-                Field::new(field.name(), DataType::BinaryView, field.is_nullable())
-                    .with_metadata(field.metadata().to_owned()),
-            ),
+            DataType::Binary => field_with_new_type(field, DataType::Utf8),
+            DataType::LargeBinary => field_with_new_type(field, DataType::LargeUtf8),
+            DataType::BinaryView => field_with_new_type(field, DataType::Utf8View),
             _ => field.clone(),
         })
         .collect();
@@ -347,35 +342,28 @@ pub(crate) fn coerce_file_schema_to_string_type(
         .map(
             |field| match (table_fields.get(field.name()), field.data_type()) {
                 // table schema uses string type, coerce the file schema to use string type
-                (Some(DataType::Utf8),
-                    DataType::Binary | DataType::LargeBinary | DataType::BinaryView) => {
+                (
+                    Some(DataType::Utf8),
+                    DataType::Binary | DataType::LargeBinary | DataType::BinaryView,
+                ) => {
                     transform = true;
-                    Arc::new(Field::new(
-                        field.name(),
-                        DataType::Utf8,
-                        field.is_nullable(),
-                    ))
+                    field_with_new_type(field, DataType::Utf8)
                 }
                 // table schema uses large string type, coerce the file schema to use large string type
-                (Some(DataType::LargeUtf8), DataType::Binary | DataType::LargeBinary | DataType::BinaryView) => {
+                (
+                    Some(DataType::LargeUtf8),
+                    DataType::Binary | DataType::LargeBinary | DataType::BinaryView,
+                ) => {
                     transform = true;
-                    Arc::new(Field::new(
-                        field.name(),
-                        DataType::LargeUtf8,
-                        field.is_nullable(),
-                    ))
+                    field_with_new_type(field, DataType::LargeUtf8)
                 }
                 // table schema uses string view type, coerce the file schema to use view type
                 (
                     Some(DataType::Utf8View),
                     DataType::Binary | DataType::LargeBinary | DataType::BinaryView,
                 ) => {
                     transform = true;
-                    Arc::new(Field::new(
-                        field.name(),
-                        DataType::Utf8View,
-                        field.is_nullable(),
-                    ))
+                    field_with_new_type(field, DataType::Utf8View)
                 }
                 _ => field.clone(),
             },