feat: Add ScalarUDF support in FFI crate (apache#14579)

* initial commit for scalar udf in ffi crate

* Add utility functions for converting back and forth to RResult

* License text

* There is no need to repeat the trait doc strings

* Resolve clippy warning

* Add unit tests for ffi scalar udfs

* Add license text

* Switch over ffi modules to use the new macros for conversion back and forth between result and rresult

* Attempting to fix CI based on recommendation to try running clean, but this shouldn't be necessary

* Revert "Attempting to fix CI based on recommendation to try running clean, but this shouldn't be necessary"

This reverts commit 10248c2.

* arrow_schema was removed during rebase

* Switch from trying to expose the entire type signature to using the user_defined type

* Call function to get valid types for scalar udf

* Adding documentation

* Resolve doctest failure

datafusion/ffi/src/arrow_wrappers.rs

@@ -19,8 +19,9 @@ use std::sync::Arc;
 
 use abi_stable::StableAbi;
 use arrow::{
+    array::{make_array, ArrayRef},
     datatypes::{Schema, SchemaRef},
-    ffi::{FFI_ArrowArray, FFI_ArrowSchema},
+    ffi::{from_ffi, FFI_ArrowArray, FFI_ArrowSchema},
 };
 use log::error;
 
@@ -68,3 +69,13 @@ pub struct WrappedArray {
 
     pub schema: WrappedSchema,
 }
+
+impl TryFrom<WrappedArray> for ArrayRef {
+    type Error = arrow::error::ArrowError;
+
+    fn try_from(value: WrappedArray) -> Result<Self, Self::Error> {
+        let data = unsafe { from_ffi(value.array, &value.schema.0)? };
+
+        Ok(make_array(data))
+    }
+}

datafusion/ffi/src/execution_plan.rs

@@ -30,7 +30,8 @@ use datafusion::{
 use tokio::runtime::Handle;
 
 use crate::{
-    plan_properties::FFI_PlanProperties, record_batch_stream::FFI_RecordBatchStream,
+    df_result, plan_properties::FFI_PlanProperties,
+    record_batch_stream::FFI_RecordBatchStream, rresult,
 };
 
 /// A stable struct for sharing a [`ExecutionPlan`] across FFI boundaries.
@@ -112,13 +113,11 @@ unsafe extern "C" fn execute_fn_wrapper(
     let ctx = &(*private_data).context;
     let runtime = (*private_data).runtime.clone();
 
-    match plan.execute(partition, Arc::clone(ctx)) {
-        Ok(rbs) => RResult::ROk(FFI_RecordBatchStream::new(rbs, runtime)),
-        Err(e) => RResult::RErr(
-            format!("Error occurred during FFI_ExecutionPlan execute: {}", e).into(),
-        ),
-    }
+    rresult!(plan
+        .execute(partition, Arc::clone(ctx))
+        .map(|rbs| FFI_RecordBatchStream::new(rbs, runtime)))
 }
+
 unsafe extern "C" fn name_fn_wrapper(plan: &FFI_ExecutionPlan) -> RString {
     let private_data = plan.private_data as *const ExecutionPlanPrivateData;
     let plan = &(*private_data).plan;
@@ -274,16 +273,8 @@ impl ExecutionPlan for ForeignExecutionPlan {
         _context: Arc<TaskContext>,
     ) -> Result<SendableRecordBatchStream> {
         unsafe {
-            match (self.plan.execute)(&self.plan, partition) {
-                RResult::ROk(stream) => {
-                    let stream = Pin::new(Box::new(stream)) as SendableRecordBatchStream;
-                    Ok(stream)
-                }
-                RResult::RErr(e) => Err(DataFusionError::Execution(format!(
-                    "Error occurred during FFI call to FFI_ExecutionPlan execute. {}",
-                    e
-                ))),
-            }
+            df_result!((self.plan.execute)(&self.plan, partition))
+                .map(|stream| Pin::new(Box::new(stream)) as SendableRecordBatchStream)
         }
     }
 }

datafusion/ffi/src/lib.rs

@@ -26,6 +26,9 @@ pub mod record_batch_stream;
 pub mod session_config;
 pub mod table_provider;
 pub mod table_source;
+pub mod udf;
+pub mod util;
+pub mod volatility;
 
 #[cfg(feature = "integration-tests")]
 pub mod tests;

datafusion/ffi/src/plan_properties.rs

@@ -19,8 +19,8 @@ use std::{ffi::c_void, sync::Arc};
 
 use abi_stable::{
     std_types::{
-        RResult::{self, RErr, ROk},
-        RStr, RVec,
+        RResult::{self, ROk},
+        RString, RVec,
     },
     StableAbi,
 };
@@ -44,7 +44,7 @@ use datafusion_proto::{
 };
 use prost::Message;
 
-use crate::arrow_wrappers::WrappedSchema;
+use crate::{arrow_wrappers::WrappedSchema, df_result, rresult_return};
 
 /// A stable struct for sharing [`PlanProperties`] across FFI boundaries.
 #[repr(C)]
@@ -54,7 +54,7 @@ pub struct FFI_PlanProperties {
     /// The output partitioning is a [`Partitioning`] protobuf message serialized
     /// into bytes to pass across the FFI boundary.
     pub output_partitioning:
-        unsafe extern "C" fn(plan: &Self) -> RResult<RVec<u8>, RStr<'static>>,
+        unsafe extern "C" fn(plan: &Self) -> RResult<RVec<u8>, RString>,
 
     /// Return the emission type of the plan.
     pub emission_type: unsafe extern "C" fn(plan: &Self) -> FFI_EmissionType,
@@ -64,8 +64,7 @@ pub struct FFI_PlanProperties {
 
     /// The output ordering is a [`PhysicalSortExprNodeCollection`] protobuf message
     /// serialized into bytes to pass across the FFI boundary.
-    pub output_ordering:
-        unsafe extern "C" fn(plan: &Self) -> RResult<RVec<u8>, RStr<'static>>,
+    pub output_ordering: unsafe extern "C" fn(plan: &Self) -> RResult<RVec<u8>, RString>,
 
     /// Return the schema of the plan.
     pub schema: unsafe extern "C" fn(plan: &Self) -> WrappedSchema,
@@ -84,21 +83,13 @@ struct PlanPropertiesPrivateData {
 
 unsafe extern "C" fn output_partitioning_fn_wrapper(
     properties: &FFI_PlanProperties,
-) -> RResult<RVec<u8>, RStr<'static>> {
+) -> RResult<RVec<u8>, RString> {
     let private_data = properties.private_data as *const PlanPropertiesPrivateData;
     let props = &(*private_data).props;
 
     let codec = DefaultPhysicalExtensionCodec {};
     let partitioning_data =
-        match serialize_partitioning(props.output_partitioning(), &codec) {
-            Ok(p) => p,
-            Err(_) => {
-                return RErr(
-                    "unable to serialize output_partitioning in FFI_PlanProperties"
-                        .into(),
-                )
-            }
-        };
+        rresult_return!(serialize_partitioning(props.output_partitioning(), &codec));
     let output_partitioning = partitioning_data.encode_to_vec();
 
     ROk(output_partitioning.into())
@@ -122,31 +113,24 @@ unsafe extern "C" fn boundedness_fn_wrapper(
 
 unsafe extern "C" fn output_ordering_fn_wrapper(
     properties: &FFI_PlanProperties,
-) -> RResult<RVec<u8>, RStr<'static>> {
+) -> RResult<RVec<u8>, RString> {
     let private_data = properties.private_data as *const PlanPropertiesPrivateData;
     let props = &(*private_data).props;
 
     let codec = DefaultPhysicalExtensionCodec {};
-    let output_ordering =
-        match props.output_ordering() {
-            Some(ordering) => {
-                let physical_sort_expr_nodes =
-                    match serialize_physical_sort_exprs(ordering.to_owned(), &codec) {
-                        Ok(v) => v,
-                        Err(_) => return RErr(
-                            "unable to serialize output_ordering in FFI_PlanProperties"
-                                .into(),
-                        ),
-                    };
-
-                let ordering_data = PhysicalSortExprNodeCollection {
-                    physical_sort_expr_nodes,
-                };
-
-                ordering_data.encode_to_vec()
-            }
-            None => Vec::default(),
-        };
+    let output_ordering = match props.output_ordering() {
+        Some(ordering) => {
+            let physical_sort_expr_nodes = rresult_return!(
+                serialize_physical_sort_exprs(ordering.to_owned(), &codec)
+            );
+            let ordering_data = PhysicalSortExprNodeCollection {
+                physical_sort_expr_nodes,
+            };
+
+            ordering_data.encode_to_vec()
+        }
+        None => Vec::default(),
+    };
     ROk(output_ordering.into())
 }
 
@@ -200,40 +184,32 @@ impl TryFrom<FFI_PlanProperties> for PlanProperties {
         let codex = DefaultPhysicalExtensionCodec {};
 
         let ffi_orderings = unsafe { (ffi_props.output_ordering)(&ffi_props) };
-        let orderings = match ffi_orderings {
-            ROk(ordering_vec) => {
-                let proto_output_ordering =
-                    PhysicalSortExprNodeCollection::decode(ordering_vec.as_ref())
-                        .map_err(|e| DataFusionError::External(Box::new(e)))?;
-                Some(parse_physical_sort_exprs(
-                    &proto_output_ordering.physical_sort_expr_nodes,
-                    &default_ctx,
-                    &schema,
-                    &codex,
-                )?)
-            }
-            RErr(e) => return Err(DataFusionError::Plan(e.to_string())),
-        };
 
-        let ffi_partitioning = unsafe { (ffi_props.output_partitioning)(&ffi_props) };
-        let partitioning = match ffi_partitioning {
-            ROk(partitioning_vec) => {
-                let proto_output_partitioning =
-                    Partitioning::decode(partitioning_vec.as_ref())
-                        .map_err(|e| DataFusionError::External(Box::new(e)))?;
-                parse_protobuf_partitioning(
-                    Some(&proto_output_partitioning),
-                    &default_ctx,
-                    &schema,
-                    &codex,
-                )?
-                .ok_or(DataFusionError::Plan(
-                    "Unable to deserialize partitioning protobuf in FFI_PlanProperties"
-                        .to_string(),
-                ))
-            }
-            RErr(e) => Err(DataFusionError::Plan(e.to_string())),
-        }?;
+        let proto_output_ordering =
+            PhysicalSortExprNodeCollection::decode(df_result!(ffi_orderings)?.as_ref())
+                .map_err(|e| DataFusionError::External(Box::new(e)))?;
+        let orderings = Some(parse_physical_sort_exprs(
+            &proto_output_ordering.physical_sort_expr_nodes,
+            &default_ctx,
+            &schema,
+            &codex,
+        )?);
+
+        let partitioning_vec =
+            unsafe { df_result!((ffi_props.output_partitioning)(&ffi_props))? };
+        let proto_output_partitioning =
+            Partitioning::decode(partitioning_vec.as_ref())
+                .map_err(|e| DataFusionError::External(Box::new(e)))?;
+        let partitioning = parse_protobuf_partitioning(
+            Some(&proto_output_partitioning),
+            &default_ctx,
+            &schema,
+            &codex,
+        )?
+        .ok_or(DataFusionError::Plan(
+            "Unable to deserialize partitioning protobuf in FFI_PlanProperties"
+                .to_string(),
+        ))?;
 
         let eq_properties = match orderings {
             Some(ordering) => {

datafusion/ffi/src/record_batch_stream.rs

@@ -35,7 +35,10 @@ use datafusion::{
 use futures::{Stream, TryStreamExt};
 use tokio::runtime::Handle;
 
-use crate::arrow_wrappers::{WrappedArray, WrappedSchema};
+use crate::{
+    arrow_wrappers::{WrappedArray, WrappedSchema},
+    rresult,
+};
 
 /// A stable struct for sharing [`RecordBatchStream`] across FFI boundaries.
 /// We use the async-ffi crate for handling async calls across libraries.
@@ -97,13 +100,12 @@ fn record_batch_to_wrapped_array(
     record_batch: RecordBatch,
 ) -> RResult<WrappedArray, RString> {
     let struct_array = StructArray::from(record_batch);
-    match to_ffi(&struct_array.to_data()) {
-        Ok((array, schema)) => RResult::ROk(WrappedArray {
+    rresult!(
+        to_ffi(&struct_array.to_data()).map(|(array, schema)| WrappedArray {
             array,
-            schema: WrappedSchema(schema),
-        }),
-        Err(e) => RResult::RErr(e.to_string().into()),
-    }
+            schema: WrappedSchema(schema)
+        })
+    )
 }
 
 // probably want to use pub unsafe fn from_ffi(array: FFI_ArrowArray, schema: &FFI_ArrowSchema) -> Result<ArrayData> {