Implement Field FFI (#5)

arro3-core/src/ffi/from_python/field.rs

@@ -1,13 +1,17 @@
+use std::sync::Arc;
+
 use crate::ffi::from_python::utils::import_arrow_c_schema;
 use crate::field::PyField;
+use arrow_schema::Field;
+use pyo3::exceptions::PyTypeError;
 use pyo3::prelude::*;
 use pyo3::{PyAny, PyResult};
 
-// TODO: need to update import_arrow_c_schema to not always coerce to a Schema
-// impl<'a> FromPyObject<'a> for PyField {
-//     fn extract(ob: &'a PyAny) -> PyResult<Self> {
-//         let schema = import_arrow_c_schema(ob)?;
-//         schema.fi
-//         Ok(Self(schema))
-//     }
-// }
+impl<'a> FromPyObject<'a> for PyField {
+    fn extract(ob: &'a PyAny) -> PyResult<Self> {
+        let schema_ptr = import_arrow_c_schema(ob)?;
+        let field =
+            Field::try_from(schema_ptr).map_err(|err| PyTypeError::new_err(err.to_string()))?;
+        Ok(Self::new(Arc::new(field)))
+    }
+}

arro3-core/src/ffi/from_python/mod.rs

@@ -1,7 +1,7 @@
 pub mod array;
 pub mod chunked;
 pub mod ffi_stream;
-// pub mod field;
+pub mod field;
 pub mod record_batch;
 pub mod schema;
 pub mod table;

arro3-core/src/ffi/from_python/schema.rs

@@ -1,11 +1,17 @@
+use std::sync::Arc;
+
 use crate::ffi::from_python::utils::import_arrow_c_schema;
 use crate::schema::PySchema;
+use arrow_schema::Schema;
+use pyo3::exceptions::PyTypeError;
 use pyo3::prelude::*;
 use pyo3::{PyAny, PyResult};
 
 impl<'a> FromPyObject<'a> for PySchema {
     fn extract(ob: &'a PyAny) -> PyResult<Self> {
-        let schema = import_arrow_c_schema(ob)?;
-        Ok(Self::new(schema))
+        let schema_ptr = import_arrow_c_schema(ob)?;
+        let schema =
+            Schema::try_from(schema_ptr).map_err(|err| PyTypeError::new_err(err.to_string()))?;
+        Ok(Self::new(Arc::new(schema)))
     }
 }

arro3-core/src/ffi/from_python/utils.rs

@@ -1,6 +1,4 @@
-use std::sync::Arc;
-
-use arrow::datatypes::{Field, Schema, SchemaRef};
+use arrow::datatypes::Field;
 use arrow::ffi::{FFI_ArrowArray, FFI_ArrowSchema};
 use arrow::ffi_stream::FFI_ArrowArrayStream;
 use arrow_array::{make_array, ArrayRef};
@@ -30,7 +28,7 @@ pub fn validate_pycapsule_name(capsule: &PyCapsule, expected_name: &str) -> PyRe
 }
 
 /// Import `__arrow_c_schema__` across Python boundary
-pub(crate) fn import_arrow_c_schema(ob: &PyAny) -> PyResult<SchemaRef> {
+pub(crate) fn import_arrow_c_schema(ob: &PyAny) -> PyResult<&FFI_ArrowSchema> {
     if !ob.hasattr("__arrow_c_schema__")? {
         return Err(PyValueError::new_err(
             "Expected an object with dunder __arrow_c_schema__",
@@ -41,9 +39,7 @@ pub(crate) fn import_arrow_c_schema(ob: &PyAny) -> PyResult<SchemaRef> {
     validate_pycapsule_name(capsule, "arrow_schema")?;
 
     let schema_ptr = unsafe { capsule.reference::<FFI_ArrowSchema>() };
-    let schema =
-        Schema::try_from(schema_ptr).map_err(|err| PyTypeError::new_err(err.to_string()))?;
-    Ok(Arc::new(schema))
+    Ok(schema_ptr)
 }
 
 /// Import `__arrow_c_array__` across Python boundary

arro3-core/src/lib.rs

@@ -29,11 +29,5 @@ fn _rust(_py: Python, m: &PyModule) -> PyResult<()> {
     m.add_class::<schema::PySchema>()?;
     m.add_class::<table::PyTable>()?;
 
-    // Top-level array/chunked array functions
-    // m.add_function(wrap_pyfunction!(
-    //     crate::algorithm::geo::affine_ops::affine_transform,
-    //     m
-    // )?)?;
-
     Ok(())
 }