timsaucer commented on code in PR #20326: URL: https://github.com/apache/datafusion/pull/20326#discussion_r2814437253
########## datafusion/ffi/src/table_provider_factory.rs: ########## @@ -0,0 +1,492 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +use std::{ffi::c_void, sync::Arc}; + +use abi_stable::{ + StableAbi, + std_types::{RResult, RString, RVec}, +}; +use async_ffi::{FfiFuture, FutureExt}; +use async_trait::async_trait; +use datafusion_catalog::{Session, TableProvider, TableProviderFactory}; +use datafusion_common::TableReference; +use datafusion_common::error::{DataFusionError, Result}; +use datafusion_execution::TaskContext; +use datafusion_expr::CreateExternalTable; +use datafusion_proto::logical_plan::from_proto::{parse_expr, parse_sorts}; +use datafusion_proto::logical_plan::to_proto::{serialize_expr, serialize_sorts}; +use datafusion_proto::logical_plan::{ + DefaultLogicalExtensionCodec, LogicalExtensionCodec, +}; +use datafusion_proto::protobuf::{CreateExternalTableNode, SortExprNodeCollection}; +use prost::Message; +use std::collections::HashMap; +use tokio::runtime::Handle; + +use crate::execution::FFI_TaskContextProvider; +use crate::proto::logical_extension_codec::FFI_LogicalExtensionCodec; +use crate::session::{FFI_SessionRef, ForeignSession}; +use crate::table_provider::{FFI_TableProvider, ForeignTableProvider}; +use crate::{df_result, rresult_return}; + +/// A stable struct for sharing [`TableProviderFactory`] across FFI boundaries. +/// +/// Similar to [`FFI_TableProvider`], this struct uses the FFI-safe pattern where: +/// - The `FFI_*` struct exposes stable function pointers +/// - Private data is stored as an opaque pointer +/// - The `Foreign*` wrapper is used by consumers on the other side of the FFI boundary +/// +/// [`FFI_TableProvider`]: crate::table_provider::FFI_TableProvider +#[repr(C)] +#[derive(Debug, StableAbi)] +pub struct FFI_TableProviderFactory { + /// Create a TableProvider with the given command. + /// + /// # Arguments + /// + /// * `factory` - the table provider factory + /// * `session_config` - session configuration + /// * `cmd_serialized` - a [`CreateExternalTableNode`] protobuf message serialized into bytes + /// to pass across the FFI boundary. + create: unsafe extern "C" fn( + factory: &Self, + session: FFI_SessionRef, + cmd_serialized: RVec<u8>, + ) -> FfiFuture<RResult<FFI_TableProvider, RString>>, + + pub logical_codec: FFI_LogicalExtensionCodec, + + /// Used to create a clone of the factory. This should only need to be called + /// by the receiver of the factory. + pub clone: unsafe extern "C" fn(factory: &Self) -> Self, Review Comment: minor: I've come to realize that many of the structs in this crate have these functions all `pub` but don't need to be. I'm doing drive by cleanup when I come across them. ########## datafusion/ffi/src/table_provider_factory.rs: ########## @@ -0,0 +1,492 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +use std::{ffi::c_void, sync::Arc}; + +use abi_stable::{ + StableAbi, + std_types::{RResult, RString, RVec}, +}; +use async_ffi::{FfiFuture, FutureExt}; +use async_trait::async_trait; +use datafusion_catalog::{Session, TableProvider, TableProviderFactory}; +use datafusion_common::TableReference; +use datafusion_common::error::{DataFusionError, Result}; +use datafusion_execution::TaskContext; +use datafusion_expr::CreateExternalTable; +use datafusion_proto::logical_plan::from_proto::{parse_expr, parse_sorts}; +use datafusion_proto::logical_plan::to_proto::{serialize_expr, serialize_sorts}; +use datafusion_proto::logical_plan::{ + DefaultLogicalExtensionCodec, LogicalExtensionCodec, +}; +use datafusion_proto::protobuf::{CreateExternalTableNode, SortExprNodeCollection}; +use prost::Message; +use std::collections::HashMap; +use tokio::runtime::Handle; + +use crate::execution::FFI_TaskContextProvider; +use crate::proto::logical_extension_codec::FFI_LogicalExtensionCodec; +use crate::session::{FFI_SessionRef, ForeignSession}; +use crate::table_provider::{FFI_TableProvider, ForeignTableProvider}; +use crate::{df_result, rresult_return}; + +/// A stable struct for sharing [`TableProviderFactory`] across FFI boundaries. +/// +/// Similar to [`FFI_TableProvider`], this struct uses the FFI-safe pattern where: +/// - The `FFI_*` struct exposes stable function pointers +/// - Private data is stored as an opaque pointer +/// - The `Foreign*` wrapper is used by consumers on the other side of the FFI boundary +/// +/// [`FFI_TableProvider`]: crate::table_provider::FFI_TableProvider +#[repr(C)] +#[derive(Debug, StableAbi)] +pub struct FFI_TableProviderFactory { + /// Create a TableProvider with the given command. + /// + /// # Arguments + /// + /// * `factory` - the table provider factory + /// * `session_config` - session configuration + /// * `cmd_serialized` - a [`CreateExternalTableNode`] protobuf message serialized into bytes + /// to pass across the FFI boundary. + create: unsafe extern "C" fn( + factory: &Self, + session: FFI_SessionRef, + cmd_serialized: RVec<u8>, + ) -> FfiFuture<RResult<FFI_TableProvider, RString>>, + + pub logical_codec: FFI_LogicalExtensionCodec, + + /// Used to create a clone of the factory. This should only need to be called + /// by the receiver of the factory. + pub clone: unsafe extern "C" fn(factory: &Self) -> Self, + + /// Release the memory of the private data when it is no longer being used. + pub release: unsafe extern "C" fn(factory: &mut Self), + + /// Return the major DataFusion version number of this factory. + pub version: unsafe extern "C" fn() -> u64, + + /// Internal data. This is only to be accessed by the provider of the factory. + /// A [`ForeignTableProviderFactory`] should never attempt to access this data. + pub private_data: *mut c_void, + + /// Utility to identify when FFI objects are accessed locally through + /// the foreign interface. See [`crate::get_library_marker_id`] and + /// the crate's `README.md` for more information. + pub library_marker_id: extern "C" fn() -> usize, +} + +unsafe impl Send for FFI_TableProviderFactory {} +unsafe impl Sync for FFI_TableProviderFactory {} + +struct FactoryPrivateData { + factory: Arc<dyn TableProviderFactory + Send>, + runtime: Option<Handle>, +} + +impl FFI_TableProviderFactory { + /// Creates a new [`FFI_TableProvider`]. + pub fn new( + factory: Arc<dyn TableProviderFactory + Send>, + runtime: Option<Handle>, + task_ctx_provider: impl Into<FFI_TaskContextProvider>, + logical_codec: Option<Arc<dyn LogicalExtensionCodec>>, + ) -> Self { + let task_ctx_provider = task_ctx_provider.into(); + let logical_codec = + logical_codec.unwrap_or_else(|| Arc::new(DefaultLogicalExtensionCodec {})); + let logical_codec = FFI_LogicalExtensionCodec::new( + logical_codec, + runtime.clone(), + task_ctx_provider.clone(), + ); + Self::new_with_ffi_codec(factory, runtime, logical_codec) + } + + pub fn new_with_ffi_codec( + factory: Arc<dyn TableProviderFactory + Send>, + runtime: Option<Handle>, + logical_codec: FFI_LogicalExtensionCodec, + ) -> Self { + let private_data = Box::new(FactoryPrivateData { factory, runtime }); + + Self { + create: create_fn_wrapper, + logical_codec, + clone: clone_fn_wrapper, + release: release_fn_wrapper, + version: super::version, + private_data: Box::into_raw(private_data) as *mut c_void, + library_marker_id: crate::get_library_marker_id, + } + } + + fn inner(&self) -> &Arc<dyn TableProviderFactory + Send> { + let private_data = self.private_data as *const FactoryPrivateData; + unsafe { &(*private_data).factory } + } + + fn runtime(&self) -> &Option<Handle> { + let private_data = self.private_data as *const FactoryPrivateData; + unsafe { &(*private_data).runtime } + } +} + +impl Clone for FFI_TableProviderFactory { + fn clone(&self) -> Self { + unsafe { (self.clone)(self) } + } +} + +impl Drop for FFI_TableProviderFactory { + fn drop(&mut self) { + unsafe { (self.release)(self) } + } +} + +unsafe extern "C" fn create_fn_wrapper( + factory: &FFI_TableProviderFactory, + session: FFI_SessionRef, + cmd_serialized: RVec<u8>, +) -> FfiFuture<RResult<FFI_TableProvider, RString>> { + let task_ctx: Result<Arc<TaskContext>, DataFusionError> = + (&factory.logical_codec.task_ctx_provider).try_into(); + let runtime = factory.runtime().clone(); + let logical_codec: Arc<dyn LogicalExtensionCodec> = (&factory.logical_codec).into(); + let ffi_logical_codec = factory.logical_codec.clone(); + let internal_factory = Arc::clone(factory.inner()); + + async move { + let mut foreign_session = None; + let session = rresult_return!( + session + .as_local() + .map(Ok::<&(dyn Session + Send + Sync), DataFusionError>) + .unwrap_or_else(|| { + foreign_session = Some(ForeignSession::try_from(&session)?); + Ok(foreign_session.as_ref().unwrap()) + }) + ); + + let task_ctx = rresult_return!(task_ctx); + + let proto_cmd = + rresult_return!(CreateExternalTableNode::decode(cmd_serialized.as_ref())); + + // Deserialize CreateExternalTable from protobuf + let pb_schema = rresult_return!(proto_cmd.schema.ok_or_else(|| { + DataFusionError::Internal( + "CreateExternalTableNode was missing required field schema".to_string(), + ) + })); + + let constraints = rresult_return!(proto_cmd.constraints.ok_or_else(|| { + DataFusionError::Internal( + "CreateExternalTableNode was missing required field constraints" + .to_string(), + ) + })); + + let definition = if !proto_cmd.definition.is_empty() { + Some(proto_cmd.definition) + } else { + None + }; + + let mut order_exprs = Vec::with_capacity(proto_cmd.order_exprs.len()); + for expr in &proto_cmd.order_exprs { + let sorts = rresult_return!(parse_sorts( + &expr.sort_expr_nodes, + task_ctx.as_ref(), + logical_codec.as_ref(), + )); + order_exprs.push(sorts); + } + + let mut column_defaults = HashMap::with_capacity(proto_cmd.column_defaults.len()); + for (col_name, expr) in &proto_cmd.column_defaults { + let expr = rresult_return!(parse_expr( + expr, + task_ctx.as_ref(), + logical_codec.as_ref() + )); + column_defaults.insert(col_name.clone(), expr); + } + + let table_ref = rresult_return!(proto_cmd.name.as_ref().ok_or_else(|| { + DataFusionError::Internal( + "CreateExternalTableNode was missing required field name".to_string(), + ) + })); + + let name: TableReference = rresult_return!(table_ref.clone().try_into()); + + let cmd = CreateExternalTable { + schema: rresult_return!(pb_schema.try_into()), + name, + location: proto_cmd.location, + file_type: proto_cmd.file_type, + table_partition_cols: proto_cmd.table_partition_cols, + order_exprs, + if_not_exists: proto_cmd.if_not_exists, + or_replace: proto_cmd.or_replace, + temporary: proto_cmd.temporary, + definition, + unbounded: proto_cmd.unbounded, + options: proto_cmd.options, + constraints: constraints.into(), + column_defaults, + }; + + let provider = rresult_return!(internal_factory.create(session, &cmd).await); + + RResult::ROk(FFI_TableProvider::new_with_ffi_codec( + provider, + true, + runtime.clone(), + ffi_logical_codec, + )) + } + .into_ffi() +} + +unsafe extern "C" fn clone_fn_wrapper( + factory: &FFI_TableProviderFactory, +) -> FFI_TableProviderFactory { + let runtime = factory.runtime().clone(); + let old_factory = Arc::clone(factory.inner()); + + let private_data = Box::into_raw(Box::new(FactoryPrivateData { + factory: old_factory, + runtime, + })) as *mut c_void; + + FFI_TableProviderFactory { + create: create_fn_wrapper, + logical_codec: factory.logical_codec.clone(), + clone: clone_fn_wrapper, + release: release_fn_wrapper, + version: super::version, + private_data, + library_marker_id: crate::get_library_marker_id, + } +} + +unsafe extern "C" fn release_fn_wrapper(factory: &mut FFI_TableProviderFactory) { + unsafe { + debug_assert!(!factory.private_data.is_null()); + let private_data = Box::from_raw(factory.private_data as *mut FactoryPrivateData); + drop(private_data); + factory.private_data = std::ptr::null_mut(); + } +} + +/// This wrapper struct exists on the receiver side of the FFI interface, so it has +/// no guarantees about being able to access the data in `private_data`. Any functions +/// defined on this struct must only use the stable functions provided in +/// FFI_TableProviderFactory to interact with the foreign table provider factory. +#[derive(Debug)] +pub struct ForeignTableProviderFactory(pub FFI_TableProviderFactory); + +impl From<&FFI_TableProviderFactory> for Arc<dyn TableProviderFactory> { + fn from(factory: &FFI_TableProviderFactory) -> Self { + if (factory.library_marker_id)() == crate::get_library_marker_id() { + Arc::clone(factory.inner()) as Arc<dyn TableProviderFactory> + } else { + Arc::new(ForeignTableProviderFactory(factory.clone())) + } + } +} + +unsafe impl Send for ForeignTableProviderFactory {} +unsafe impl Sync for ForeignTableProviderFactory {} + +#[async_trait] +impl TableProviderFactory for ForeignTableProviderFactory { + async fn create( + &self, + session: &dyn Session, + cmd: &CreateExternalTable, + ) -> Result<Arc<dyn TableProvider>> { + let session = FFI_SessionRef::new(session, None, self.0.logical_codec.clone()); Review Comment: Just to share more widely, when using `FFI_SessionRef` we do not maintain guarantees about lifetime when it gets shared over the FFI boundary. It is *essential* that your function here never keeps the session around any longer than it's valid. This looks like it's good to me. ########## datafusion/ffi/src/table_provider_factory.rs: ########## @@ -0,0 +1,492 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +use std::{ffi::c_void, sync::Arc}; + +use abi_stable::{ + StableAbi, + std_types::{RResult, RString, RVec}, +}; +use async_ffi::{FfiFuture, FutureExt}; +use async_trait::async_trait; +use datafusion_catalog::{Session, TableProvider, TableProviderFactory}; +use datafusion_common::TableReference; +use datafusion_common::error::{DataFusionError, Result}; +use datafusion_execution::TaskContext; +use datafusion_expr::CreateExternalTable; +use datafusion_proto::logical_plan::from_proto::{parse_expr, parse_sorts}; +use datafusion_proto::logical_plan::to_proto::{serialize_expr, serialize_sorts}; +use datafusion_proto::logical_plan::{ + DefaultLogicalExtensionCodec, LogicalExtensionCodec, +}; +use datafusion_proto::protobuf::{CreateExternalTableNode, SortExprNodeCollection}; +use prost::Message; +use std::collections::HashMap; +use tokio::runtime::Handle; + +use crate::execution::FFI_TaskContextProvider; +use crate::proto::logical_extension_codec::FFI_LogicalExtensionCodec; +use crate::session::{FFI_SessionRef, ForeignSession}; +use crate::table_provider::{FFI_TableProvider, ForeignTableProvider}; +use crate::{df_result, rresult_return}; + +/// A stable struct for sharing [`TableProviderFactory`] across FFI boundaries. +/// +/// Similar to [`FFI_TableProvider`], this struct uses the FFI-safe pattern where: +/// - The `FFI_*` struct exposes stable function pointers +/// - Private data is stored as an opaque pointer +/// - The `Foreign*` wrapper is used by consumers on the other side of the FFI boundary +/// +/// [`FFI_TableProvider`]: crate::table_provider::FFI_TableProvider +#[repr(C)] +#[derive(Debug, StableAbi)] +pub struct FFI_TableProviderFactory { + /// Create a TableProvider with the given command. + /// + /// # Arguments + /// + /// * `factory` - the table provider factory + /// * `session_config` - session configuration + /// * `cmd_serialized` - a [`CreateExternalTableNode`] protobuf message serialized into bytes + /// to pass across the FFI boundary. + create: unsafe extern "C" fn( + factory: &Self, + session: FFI_SessionRef, + cmd_serialized: RVec<u8>, + ) -> FfiFuture<RResult<FFI_TableProvider, RString>>, + + pub logical_codec: FFI_LogicalExtensionCodec, + + /// Used to create a clone of the factory. This should only need to be called + /// by the receiver of the factory. + pub clone: unsafe extern "C" fn(factory: &Self) -> Self, + + /// Release the memory of the private data when it is no longer being used. + pub release: unsafe extern "C" fn(factory: &mut Self), + + /// Return the major DataFusion version number of this factory. + pub version: unsafe extern "C" fn() -> u64, + + /// Internal data. This is only to be accessed by the provider of the factory. + /// A [`ForeignTableProviderFactory`] should never attempt to access this data. + pub private_data: *mut c_void, + + /// Utility to identify when FFI objects are accessed locally through + /// the foreign interface. See [`crate::get_library_marker_id`] and + /// the crate's `README.md` for more information. + pub library_marker_id: extern "C" fn() -> usize, +} + +unsafe impl Send for FFI_TableProviderFactory {} +unsafe impl Sync for FFI_TableProviderFactory {} + +struct FactoryPrivateData { + factory: Arc<dyn TableProviderFactory + Send>, + runtime: Option<Handle>, +} + +impl FFI_TableProviderFactory { + /// Creates a new [`FFI_TableProvider`]. + pub fn new( + factory: Arc<dyn TableProviderFactory + Send>, + runtime: Option<Handle>, + task_ctx_provider: impl Into<FFI_TaskContextProvider>, + logical_codec: Option<Arc<dyn LogicalExtensionCodec>>, + ) -> Self { + let task_ctx_provider = task_ctx_provider.into(); + let logical_codec = + logical_codec.unwrap_or_else(|| Arc::new(DefaultLogicalExtensionCodec {})); + let logical_codec = FFI_LogicalExtensionCodec::new( + logical_codec, + runtime.clone(), + task_ctx_provider.clone(), + ); + Self::new_with_ffi_codec(factory, runtime, logical_codec) + } + + pub fn new_with_ffi_codec( + factory: Arc<dyn TableProviderFactory + Send>, + runtime: Option<Handle>, + logical_codec: FFI_LogicalExtensionCodec, + ) -> Self { + let private_data = Box::new(FactoryPrivateData { factory, runtime }); + + Self { + create: create_fn_wrapper, + logical_codec, + clone: clone_fn_wrapper, + release: release_fn_wrapper, + version: super::version, + private_data: Box::into_raw(private_data) as *mut c_void, + library_marker_id: crate::get_library_marker_id, + } + } + + fn inner(&self) -> &Arc<dyn TableProviderFactory + Send> { + let private_data = self.private_data as *const FactoryPrivateData; + unsafe { &(*private_data).factory } + } + + fn runtime(&self) -> &Option<Handle> { + let private_data = self.private_data as *const FactoryPrivateData; + unsafe { &(*private_data).runtime } + } +} + +impl Clone for FFI_TableProviderFactory { + fn clone(&self) -> Self { + unsafe { (self.clone)(self) } + } +} + +impl Drop for FFI_TableProviderFactory { + fn drop(&mut self) { + unsafe { (self.release)(self) } + } +} + +unsafe extern "C" fn create_fn_wrapper( + factory: &FFI_TableProviderFactory, + session: FFI_SessionRef, + cmd_serialized: RVec<u8>, +) -> FfiFuture<RResult<FFI_TableProvider, RString>> { + let task_ctx: Result<Arc<TaskContext>, DataFusionError> = + (&factory.logical_codec.task_ctx_provider).try_into(); + let runtime = factory.runtime().clone(); + let logical_codec: Arc<dyn LogicalExtensionCodec> = (&factory.logical_codec).into(); + let ffi_logical_codec = factory.logical_codec.clone(); + let internal_factory = Arc::clone(factory.inner()); + + async move { + let mut foreign_session = None; + let session = rresult_return!( + session + .as_local() + .map(Ok::<&(dyn Session + Send + Sync), DataFusionError>) + .unwrap_or_else(|| { + foreign_session = Some(ForeignSession::try_from(&session)?); + Ok(foreign_session.as_ref().unwrap()) + }) + ); + + let task_ctx = rresult_return!(task_ctx); + + let proto_cmd = + rresult_return!(CreateExternalTableNode::decode(cmd_serialized.as_ref())); + + // Deserialize CreateExternalTable from protobuf + let pb_schema = rresult_return!(proto_cmd.schema.ok_or_else(|| { + DataFusionError::Internal( + "CreateExternalTableNode was missing required field schema".to_string(), + ) + })); + + let constraints = rresult_return!(proto_cmd.constraints.ok_or_else(|| { + DataFusionError::Internal( + "CreateExternalTableNode was missing required field constraints" + .to_string(), + ) + })); + + let definition = if !proto_cmd.definition.is_empty() { + Some(proto_cmd.definition) + } else { + None + }; + + let mut order_exprs = Vec::with_capacity(proto_cmd.order_exprs.len()); + for expr in &proto_cmd.order_exprs { + let sorts = rresult_return!(parse_sorts( + &expr.sort_expr_nodes, + task_ctx.as_ref(), + logical_codec.as_ref(), + )); + order_exprs.push(sorts); + } + + let mut column_defaults = HashMap::with_capacity(proto_cmd.column_defaults.len()); + for (col_name, expr) in &proto_cmd.column_defaults { + let expr = rresult_return!(parse_expr( + expr, + task_ctx.as_ref(), + logical_codec.as_ref() + )); + column_defaults.insert(col_name.clone(), expr); + } + + let table_ref = rresult_return!(proto_cmd.name.as_ref().ok_or_else(|| { + DataFusionError::Internal( + "CreateExternalTableNode was missing required field name".to_string(), + ) + })); + + let name: TableReference = rresult_return!(table_ref.clone().try_into()); + + let cmd = CreateExternalTable { + schema: rresult_return!(pb_schema.try_into()), + name, + location: proto_cmd.location, + file_type: proto_cmd.file_type, + table_partition_cols: proto_cmd.table_partition_cols, + order_exprs, + if_not_exists: proto_cmd.if_not_exists, + or_replace: proto_cmd.or_replace, + temporary: proto_cmd.temporary, + definition, + unbounded: proto_cmd.unbounded, + options: proto_cmd.options, + constraints: constraints.into(), + column_defaults, + }; + + let provider = rresult_return!(internal_factory.create(session, &cmd).await); + + RResult::ROk(FFI_TableProvider::new_with_ffi_codec( + provider, + true, + runtime.clone(), + ffi_logical_codec, + )) + } + .into_ffi() +} + +unsafe extern "C" fn clone_fn_wrapper( + factory: &FFI_TableProviderFactory, +) -> FFI_TableProviderFactory { + let runtime = factory.runtime().clone(); + let old_factory = Arc::clone(factory.inner()); + + let private_data = Box::into_raw(Box::new(FactoryPrivateData { + factory: old_factory, + runtime, + })) as *mut c_void; + + FFI_TableProviderFactory { + create: create_fn_wrapper, + logical_codec: factory.logical_codec.clone(), + clone: clone_fn_wrapper, + release: release_fn_wrapper, + version: super::version, + private_data, + library_marker_id: crate::get_library_marker_id, + } +} + +unsafe extern "C" fn release_fn_wrapper(factory: &mut FFI_TableProviderFactory) { + unsafe { + debug_assert!(!factory.private_data.is_null()); + let private_data = Box::from_raw(factory.private_data as *mut FactoryPrivateData); + drop(private_data); + factory.private_data = std::ptr::null_mut(); + } +} + +/// This wrapper struct exists on the receiver side of the FFI interface, so it has +/// no guarantees about being able to access the data in `private_data`. Any functions +/// defined on this struct must only use the stable functions provided in +/// FFI_TableProviderFactory to interact with the foreign table provider factory. +#[derive(Debug)] +pub struct ForeignTableProviderFactory(pub FFI_TableProviderFactory); + +impl From<&FFI_TableProviderFactory> for Arc<dyn TableProviderFactory> { + fn from(factory: &FFI_TableProviderFactory) -> Self { + if (factory.library_marker_id)() == crate::get_library_marker_id() { + Arc::clone(factory.inner()) as Arc<dyn TableProviderFactory> + } else { + Arc::new(ForeignTableProviderFactory(factory.clone())) + } + } +} + +unsafe impl Send for ForeignTableProviderFactory {} +unsafe impl Sync for ForeignTableProviderFactory {} + +#[async_trait] +impl TableProviderFactory for ForeignTableProviderFactory { + async fn create( + &self, + session: &dyn Session, + cmd: &CreateExternalTable, + ) -> Result<Arc<dyn TableProvider>> { + let session = FFI_SessionRef::new(session, None, self.0.logical_codec.clone()); + + let codec: Arc<dyn LogicalExtensionCodec> = (&self.0.logical_codec).into(); + + // Serialize CreateExternalTable to protobuf + let mut converted_order_exprs: Vec<SortExprNodeCollection> = vec![]; + for order in &cmd.order_exprs { + let temp = SortExprNodeCollection { + sort_expr_nodes: serialize_sorts(order, codec.as_ref())?, + }; + converted_order_exprs.push(temp); + } + + let mut converted_column_defaults = + HashMap::with_capacity(cmd.column_defaults.len()); + for (col_name, expr) in &cmd.column_defaults { + converted_column_defaults + .insert(col_name.clone(), serialize_expr(expr, codec.as_ref())?); + } + + let proto_cmd = CreateExternalTableNode { + name: Some(cmd.name.clone().into()), + location: cmd.location.clone(), + file_type: cmd.file_type.clone(), + schema: Some(cmd.schema.as_ref().try_into()?), + table_partition_cols: cmd.table_partition_cols.clone(), + if_not_exists: cmd.if_not_exists, + or_replace: cmd.or_replace, + temporary: cmd.temporary, + order_exprs: converted_order_exprs, + definition: cmd.definition.clone().unwrap_or_default(), + unbounded: cmd.unbounded, + options: cmd.options.clone(), + constraints: Some(cmd.constraints.clone().into()), + column_defaults: converted_column_defaults, + }; + + let cmd_serialized = proto_cmd.encode_to_vec().into(); + + let provider = unsafe { + let maybe_provider = (self.0.create)(&self.0, session, cmd_serialized).await; + + let ffi_provider = df_result!(maybe_provider)?; + ForeignTableProvider(ffi_provider) + }; + + Ok(Arc::new(provider)) + } +} + +#[cfg(test)] +mod tests { + use arrow::datatypes::Schema; + use datafusion::prelude::SessionContext; + use datafusion_common::ToDFSchema; + use datafusion_execution::TaskContextProvider; + use std::collections::HashMap; + + use super::*; + + #[derive(Debug)] + struct TestTableProviderFactory {} + + #[async_trait] + impl TableProviderFactory for TestTableProviderFactory { + async fn create( + &self, + _session: &dyn Session, + _cmd: &CreateExternalTable, + ) -> Result<Arc<dyn TableProvider>> { + use arrow::datatypes::Field; + use datafusion::arrow::array::Float32Array; + use datafusion::arrow::datatypes::DataType; + use datafusion::arrow::record_batch::RecordBatch; + use datafusion::datasource::MemTable; + + let schema = + Arc::new(Schema::new(vec![Field::new("a", DataType::Float32, false)])); + + let batch1 = RecordBatch::try_new( + Arc::clone(&schema), + vec![Arc::new(Float32Array::from(vec![2.0, 4.0, 8.0]))], + )?; + let batch2 = RecordBatch::try_new( + Arc::clone(&schema), + vec![Arc::new(Float32Array::from(vec![64.0]))], + )?; + + Ok(Arc::new(MemTable::try_new( + schema, + vec![vec![batch1], vec![batch2]], + )?)) + } + } + + #[tokio::test] + async fn test_round_trip_ffi_table_provider_factory() -> Result<()> { + let ctx = Arc::new(SessionContext::new()); + let task_ctx_provider = Arc::clone(&ctx) as Arc<dyn TaskContextProvider>; + let task_ctx_provider = FFI_TaskContextProvider::from(&task_ctx_provider); + + let factory = Arc::new(TestTableProviderFactory {}); + let ffi_factory = + FFI_TableProviderFactory::new(factory, None, task_ctx_provider, None); Review Comment: We should overwrite the library marker method in this test so that it does create the Foreign struct. ########## datafusion/ffi/src/table_provider_factory.rs: ########## @@ -0,0 +1,492 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +use std::{ffi::c_void, sync::Arc}; + +use abi_stable::{ + StableAbi, + std_types::{RResult, RString, RVec}, +}; +use async_ffi::{FfiFuture, FutureExt}; +use async_trait::async_trait; +use datafusion_catalog::{Session, TableProvider, TableProviderFactory}; +use datafusion_common::TableReference; +use datafusion_common::error::{DataFusionError, Result}; +use datafusion_execution::TaskContext; +use datafusion_expr::CreateExternalTable; +use datafusion_proto::logical_plan::from_proto::{parse_expr, parse_sorts}; +use datafusion_proto::logical_plan::to_proto::{serialize_expr, serialize_sorts}; +use datafusion_proto::logical_plan::{ + DefaultLogicalExtensionCodec, LogicalExtensionCodec, +}; +use datafusion_proto::protobuf::{CreateExternalTableNode, SortExprNodeCollection}; +use prost::Message; +use std::collections::HashMap; +use tokio::runtime::Handle; + +use crate::execution::FFI_TaskContextProvider; +use crate::proto::logical_extension_codec::FFI_LogicalExtensionCodec; +use crate::session::{FFI_SessionRef, ForeignSession}; +use crate::table_provider::{FFI_TableProvider, ForeignTableProvider}; +use crate::{df_result, rresult_return}; + +/// A stable struct for sharing [`TableProviderFactory`] across FFI boundaries. +/// +/// Similar to [`FFI_TableProvider`], this struct uses the FFI-safe pattern where: +/// - The `FFI_*` struct exposes stable function pointers +/// - Private data is stored as an opaque pointer +/// - The `Foreign*` wrapper is used by consumers on the other side of the FFI boundary +/// +/// [`FFI_TableProvider`]: crate::table_provider::FFI_TableProvider +#[repr(C)] +#[derive(Debug, StableAbi)] +pub struct FFI_TableProviderFactory { + /// Create a TableProvider with the given command. + /// + /// # Arguments + /// + /// * `factory` - the table provider factory + /// * `session_config` - session configuration + /// * `cmd_serialized` - a [`CreateExternalTableNode`] protobuf message serialized into bytes + /// to pass across the FFI boundary. + create: unsafe extern "C" fn( + factory: &Self, + session: FFI_SessionRef, + cmd_serialized: RVec<u8>, + ) -> FfiFuture<RResult<FFI_TableProvider, RString>>, + + pub logical_codec: FFI_LogicalExtensionCodec, + + /// Used to create a clone of the factory. This should only need to be called + /// by the receiver of the factory. + pub clone: unsafe extern "C" fn(factory: &Self) -> Self, + + /// Release the memory of the private data when it is no longer being used. + pub release: unsafe extern "C" fn(factory: &mut Self), + + /// Return the major DataFusion version number of this factory. + pub version: unsafe extern "C" fn() -> u64, + + /// Internal data. This is only to be accessed by the provider of the factory. + /// A [`ForeignTableProviderFactory`] should never attempt to access this data. + pub private_data: *mut c_void, + + /// Utility to identify when FFI objects are accessed locally through + /// the foreign interface. See [`crate::get_library_marker_id`] and + /// the crate's `README.md` for more information. + pub library_marker_id: extern "C" fn() -> usize, +} + +unsafe impl Send for FFI_TableProviderFactory {} +unsafe impl Sync for FFI_TableProviderFactory {} + +struct FactoryPrivateData { + factory: Arc<dyn TableProviderFactory + Send>, + runtime: Option<Handle>, +} + +impl FFI_TableProviderFactory { + /// Creates a new [`FFI_TableProvider`]. + pub fn new( + factory: Arc<dyn TableProviderFactory + Send>, + runtime: Option<Handle>, + task_ctx_provider: impl Into<FFI_TaskContextProvider>, + logical_codec: Option<Arc<dyn LogicalExtensionCodec>>, + ) -> Self { + let task_ctx_provider = task_ctx_provider.into(); + let logical_codec = + logical_codec.unwrap_or_else(|| Arc::new(DefaultLogicalExtensionCodec {})); + let logical_codec = FFI_LogicalExtensionCodec::new( + logical_codec, + runtime.clone(), + task_ctx_provider.clone(), + ); + Self::new_with_ffi_codec(factory, runtime, logical_codec) + } + + pub fn new_with_ffi_codec( + factory: Arc<dyn TableProviderFactory + Send>, + runtime: Option<Handle>, + logical_codec: FFI_LogicalExtensionCodec, + ) -> Self { + let private_data = Box::new(FactoryPrivateData { factory, runtime }); + + Self { + create: create_fn_wrapper, + logical_codec, + clone: clone_fn_wrapper, + release: release_fn_wrapper, + version: super::version, + private_data: Box::into_raw(private_data) as *mut c_void, + library_marker_id: crate::get_library_marker_id, + } + } + + fn inner(&self) -> &Arc<dyn TableProviderFactory + Send> { + let private_data = self.private_data as *const FactoryPrivateData; + unsafe { &(*private_data).factory } + } + + fn runtime(&self) -> &Option<Handle> { + let private_data = self.private_data as *const FactoryPrivateData; + unsafe { &(*private_data).runtime } + } +} + +impl Clone for FFI_TableProviderFactory { + fn clone(&self) -> Self { + unsafe { (self.clone)(self) } + } +} + +impl Drop for FFI_TableProviderFactory { + fn drop(&mut self) { + unsafe { (self.release)(self) } + } +} + +unsafe extern "C" fn create_fn_wrapper( + factory: &FFI_TableProviderFactory, + session: FFI_SessionRef, + cmd_serialized: RVec<u8>, +) -> FfiFuture<RResult<FFI_TableProvider, RString>> { + let task_ctx: Result<Arc<TaskContext>, DataFusionError> = + (&factory.logical_codec.task_ctx_provider).try_into(); + let runtime = factory.runtime().clone(); + let logical_codec: Arc<dyn LogicalExtensionCodec> = (&factory.logical_codec).into(); + let ffi_logical_codec = factory.logical_codec.clone(); + let internal_factory = Arc::clone(factory.inner()); + + async move { + let mut foreign_session = None; + let session = rresult_return!( + session + .as_local() + .map(Ok::<&(dyn Session + Send + Sync), DataFusionError>) + .unwrap_or_else(|| { + foreign_session = Some(ForeignSession::try_from(&session)?); + Ok(foreign_session.as_ref().unwrap()) + }) + ); + + let task_ctx = rresult_return!(task_ctx); + + let proto_cmd = + rresult_return!(CreateExternalTableNode::decode(cmd_serialized.as_ref())); + + // Deserialize CreateExternalTable from protobuf + let pb_schema = rresult_return!(proto_cmd.schema.ok_or_else(|| { + DataFusionError::Internal( + "CreateExternalTableNode was missing required field schema".to_string(), + ) + })); + + let constraints = rresult_return!(proto_cmd.constraints.ok_or_else(|| { + DataFusionError::Internal( + "CreateExternalTableNode was missing required field constraints" + .to_string(), + ) + })); + + let definition = if !proto_cmd.definition.is_empty() { + Some(proto_cmd.definition) + } else { + None + }; + + let mut order_exprs = Vec::with_capacity(proto_cmd.order_exprs.len()); + for expr in &proto_cmd.order_exprs { + let sorts = rresult_return!(parse_sorts( + &expr.sort_expr_nodes, + task_ctx.as_ref(), + logical_codec.as_ref(), + )); + order_exprs.push(sorts); + } + + let mut column_defaults = HashMap::with_capacity(proto_cmd.column_defaults.len()); + for (col_name, expr) in &proto_cmd.column_defaults { + let expr = rresult_return!(parse_expr( + expr, + task_ctx.as_ref(), + logical_codec.as_ref() + )); + column_defaults.insert(col_name.clone(), expr); + } + + let table_ref = rresult_return!(proto_cmd.name.as_ref().ok_or_else(|| { + DataFusionError::Internal( + "CreateExternalTableNode was missing required field name".to_string(), + ) + })); + + let name: TableReference = rresult_return!(table_ref.clone().try_into()); + + let cmd = CreateExternalTable { + schema: rresult_return!(pb_schema.try_into()), + name, + location: proto_cmd.location, + file_type: proto_cmd.file_type, + table_partition_cols: proto_cmd.table_partition_cols, + order_exprs, + if_not_exists: proto_cmd.if_not_exists, + or_replace: proto_cmd.or_replace, + temporary: proto_cmd.temporary, + definition, + unbounded: proto_cmd.unbounded, + options: proto_cmd.options, + constraints: constraints.into(), + column_defaults, + }; + + let provider = rresult_return!(internal_factory.create(session, &cmd).await); + + RResult::ROk(FFI_TableProvider::new_with_ffi_codec( + provider, + true, + runtime.clone(), + ffi_logical_codec, + )) + } + .into_ffi() +} + +unsafe extern "C" fn clone_fn_wrapper( + factory: &FFI_TableProviderFactory, +) -> FFI_TableProviderFactory { + let runtime = factory.runtime().clone(); + let old_factory = Arc::clone(factory.inner()); + + let private_data = Box::into_raw(Box::new(FactoryPrivateData { + factory: old_factory, + runtime, + })) as *mut c_void; + + FFI_TableProviderFactory { + create: create_fn_wrapper, + logical_codec: factory.logical_codec.clone(), + clone: clone_fn_wrapper, + release: release_fn_wrapper, + version: super::version, + private_data, + library_marker_id: crate::get_library_marker_id, + } +} + +unsafe extern "C" fn release_fn_wrapper(factory: &mut FFI_TableProviderFactory) { + unsafe { + debug_assert!(!factory.private_data.is_null()); + let private_data = Box::from_raw(factory.private_data as *mut FactoryPrivateData); + drop(private_data); + factory.private_data = std::ptr::null_mut(); + } +} + +/// This wrapper struct exists on the receiver side of the FFI interface, so it has +/// no guarantees about being able to access the data in `private_data`. Any functions +/// defined on this struct must only use the stable functions provided in +/// FFI_TableProviderFactory to interact with the foreign table provider factory. +#[derive(Debug)] +pub struct ForeignTableProviderFactory(pub FFI_TableProviderFactory); + +impl From<&FFI_TableProviderFactory> for Arc<dyn TableProviderFactory> { + fn from(factory: &FFI_TableProviderFactory) -> Self { + if (factory.library_marker_id)() == crate::get_library_marker_id() { + Arc::clone(factory.inner()) as Arc<dyn TableProviderFactory> + } else { + Arc::new(ForeignTableProviderFactory(factory.clone())) + } + } +} + +unsafe impl Send for ForeignTableProviderFactory {} +unsafe impl Sync for ForeignTableProviderFactory {} + +#[async_trait] +impl TableProviderFactory for ForeignTableProviderFactory { + async fn create( + &self, + session: &dyn Session, + cmd: &CreateExternalTable, + ) -> Result<Arc<dyn TableProvider>> { + let session = FFI_SessionRef::new(session, None, self.0.logical_codec.clone()); + + let codec: Arc<dyn LogicalExtensionCodec> = (&self.0.logical_codec).into(); + + // Serialize CreateExternalTable to protobuf + let mut converted_order_exprs: Vec<SortExprNodeCollection> = vec![]; + for order in &cmd.order_exprs { + let temp = SortExprNodeCollection { + sort_expr_nodes: serialize_sorts(order, codec.as_ref())?, + }; + converted_order_exprs.push(temp); + } + + let mut converted_column_defaults = + HashMap::with_capacity(cmd.column_defaults.len()); + for (col_name, expr) in &cmd.column_defaults { + converted_column_defaults + .insert(col_name.clone(), serialize_expr(expr, codec.as_ref())?); + } + + let proto_cmd = CreateExternalTableNode { + name: Some(cmd.name.clone().into()), + location: cmd.location.clone(), + file_type: cmd.file_type.clone(), + schema: Some(cmd.schema.as_ref().try_into()?), + table_partition_cols: cmd.table_partition_cols.clone(), + if_not_exists: cmd.if_not_exists, + or_replace: cmd.or_replace, + temporary: cmd.temporary, + order_exprs: converted_order_exprs, + definition: cmd.definition.clone().unwrap_or_default(), + unbounded: cmd.unbounded, + options: cmd.options.clone(), + constraints: Some(cmd.constraints.clone().into()), + column_defaults: converted_column_defaults, + }; + Review Comment: Similar to the comment above, it feels like this should be lifted into a helper function and in the proto crate, but it's also a very real possibility there's something I'm missing in why it needs to be here. ########## datafusion/ffi/src/table_provider_factory.rs: ########## @@ -0,0 +1,492 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +use std::{ffi::c_void, sync::Arc}; + +use abi_stable::{ + StableAbi, + std_types::{RResult, RString, RVec}, +}; +use async_ffi::{FfiFuture, FutureExt}; +use async_trait::async_trait; +use datafusion_catalog::{Session, TableProvider, TableProviderFactory}; +use datafusion_common::TableReference; +use datafusion_common::error::{DataFusionError, Result}; +use datafusion_execution::TaskContext; +use datafusion_expr::CreateExternalTable; +use datafusion_proto::logical_plan::from_proto::{parse_expr, parse_sorts}; +use datafusion_proto::logical_plan::to_proto::{serialize_expr, serialize_sorts}; +use datafusion_proto::logical_plan::{ + DefaultLogicalExtensionCodec, LogicalExtensionCodec, +}; +use datafusion_proto::protobuf::{CreateExternalTableNode, SortExprNodeCollection}; +use prost::Message; +use std::collections::HashMap; +use tokio::runtime::Handle; + +use crate::execution::FFI_TaskContextProvider; +use crate::proto::logical_extension_codec::FFI_LogicalExtensionCodec; +use crate::session::{FFI_SessionRef, ForeignSession}; +use crate::table_provider::{FFI_TableProvider, ForeignTableProvider}; +use crate::{df_result, rresult_return}; + +/// A stable struct for sharing [`TableProviderFactory`] across FFI boundaries. +/// +/// Similar to [`FFI_TableProvider`], this struct uses the FFI-safe pattern where: +/// - The `FFI_*` struct exposes stable function pointers +/// - Private data is stored as an opaque pointer +/// - The `Foreign*` wrapper is used by consumers on the other side of the FFI boundary +/// +/// [`FFI_TableProvider`]: crate::table_provider::FFI_TableProvider +#[repr(C)] +#[derive(Debug, StableAbi)] +pub struct FFI_TableProviderFactory { + /// Create a TableProvider with the given command. + /// + /// # Arguments + /// + /// * `factory` - the table provider factory + /// * `session_config` - session configuration + /// * `cmd_serialized` - a [`CreateExternalTableNode`] protobuf message serialized into bytes + /// to pass across the FFI boundary. + create: unsafe extern "C" fn( + factory: &Self, + session: FFI_SessionRef, + cmd_serialized: RVec<u8>, + ) -> FfiFuture<RResult<FFI_TableProvider, RString>>, + + pub logical_codec: FFI_LogicalExtensionCodec, + + /// Used to create a clone of the factory. This should only need to be called + /// by the receiver of the factory. + pub clone: unsafe extern "C" fn(factory: &Self) -> Self, + + /// Release the memory of the private data when it is no longer being used. + pub release: unsafe extern "C" fn(factory: &mut Self), + + /// Return the major DataFusion version number of this factory. + pub version: unsafe extern "C" fn() -> u64, + + /// Internal data. This is only to be accessed by the provider of the factory. + /// A [`ForeignTableProviderFactory`] should never attempt to access this data. + pub private_data: *mut c_void, + + /// Utility to identify when FFI objects are accessed locally through + /// the foreign interface. See [`crate::get_library_marker_id`] and + /// the crate's `README.md` for more information. + pub library_marker_id: extern "C" fn() -> usize, +} + +unsafe impl Send for FFI_TableProviderFactory {} +unsafe impl Sync for FFI_TableProviderFactory {} + +struct FactoryPrivateData { + factory: Arc<dyn TableProviderFactory + Send>, + runtime: Option<Handle>, +} + +impl FFI_TableProviderFactory { + /// Creates a new [`FFI_TableProvider`]. + pub fn new( + factory: Arc<dyn TableProviderFactory + Send>, + runtime: Option<Handle>, + task_ctx_provider: impl Into<FFI_TaskContextProvider>, + logical_codec: Option<Arc<dyn LogicalExtensionCodec>>, + ) -> Self { + let task_ctx_provider = task_ctx_provider.into(); + let logical_codec = + logical_codec.unwrap_or_else(|| Arc::new(DefaultLogicalExtensionCodec {})); + let logical_codec = FFI_LogicalExtensionCodec::new( + logical_codec, + runtime.clone(), + task_ctx_provider.clone(), + ); + Self::new_with_ffi_codec(factory, runtime, logical_codec) + } + + pub fn new_with_ffi_codec( + factory: Arc<dyn TableProviderFactory + Send>, + runtime: Option<Handle>, + logical_codec: FFI_LogicalExtensionCodec, + ) -> Self { + let private_data = Box::new(FactoryPrivateData { factory, runtime }); + + Self { + create: create_fn_wrapper, + logical_codec, + clone: clone_fn_wrapper, + release: release_fn_wrapper, + version: super::version, + private_data: Box::into_raw(private_data) as *mut c_void, + library_marker_id: crate::get_library_marker_id, + } + } + + fn inner(&self) -> &Arc<dyn TableProviderFactory + Send> { + let private_data = self.private_data as *const FactoryPrivateData; + unsafe { &(*private_data).factory } + } + + fn runtime(&self) -> &Option<Handle> { + let private_data = self.private_data as *const FactoryPrivateData; + unsafe { &(*private_data).runtime } + } +} + +impl Clone for FFI_TableProviderFactory { + fn clone(&self) -> Self { + unsafe { (self.clone)(self) } + } +} + +impl Drop for FFI_TableProviderFactory { + fn drop(&mut self) { + unsafe { (self.release)(self) } + } +} + +unsafe extern "C" fn create_fn_wrapper( + factory: &FFI_TableProviderFactory, + session: FFI_SessionRef, + cmd_serialized: RVec<u8>, +) -> FfiFuture<RResult<FFI_TableProvider, RString>> { + let task_ctx: Result<Arc<TaskContext>, DataFusionError> = + (&factory.logical_codec.task_ctx_provider).try_into(); + let runtime = factory.runtime().clone(); + let logical_codec: Arc<dyn LogicalExtensionCodec> = (&factory.logical_codec).into(); + let ffi_logical_codec = factory.logical_codec.clone(); + let internal_factory = Arc::clone(factory.inner()); + + async move { + let mut foreign_session = None; + let session = rresult_return!( + session + .as_local() + .map(Ok::<&(dyn Session + Send + Sync), DataFusionError>) + .unwrap_or_else(|| { + foreign_session = Some(ForeignSession::try_from(&session)?); + Ok(foreign_session.as_ref().unwrap()) + }) + ); + + let task_ctx = rresult_return!(task_ctx); + + let proto_cmd = + rresult_return!(CreateExternalTableNode::decode(cmd_serialized.as_ref())); + + // Deserialize CreateExternalTable from protobuf + let pb_schema = rresult_return!(proto_cmd.schema.ok_or_else(|| { + DataFusionError::Internal( + "CreateExternalTableNode was missing required field schema".to_string(), + ) + })); + + let constraints = rresult_return!(proto_cmd.constraints.ok_or_else(|| { + DataFusionError::Internal( + "CreateExternalTableNode was missing required field constraints" + .to_string(), + ) + })); + + let definition = if !proto_cmd.definition.is_empty() { + Some(proto_cmd.definition) + } else { + None + }; + + let mut order_exprs = Vec::with_capacity(proto_cmd.order_exprs.len()); + for expr in &proto_cmd.order_exprs { + let sorts = rresult_return!(parse_sorts( + &expr.sort_expr_nodes, + task_ctx.as_ref(), + logical_codec.as_ref(), + )); + order_exprs.push(sorts); + } + + let mut column_defaults = HashMap::with_capacity(proto_cmd.column_defaults.len()); + for (col_name, expr) in &proto_cmd.column_defaults { + let expr = rresult_return!(parse_expr( + expr, + task_ctx.as_ref(), + logical_codec.as_ref() + )); + column_defaults.insert(col_name.clone(), expr); + } + Review Comment: Within this function there's a lot of `rresult_return!` macro calls. I bet we can just move the bulk of this function into a helper that returns a `Result<_, DataFusionError>` and then do the `rresult_return!` one time. More generally, this *feels* like it should be lifted into the proto crate, but I'm not familiar enough with the CreateExternalTable command to see if there is a difference in the usage here as opposed to in `LogicalPlanNode::try_into_logical_plan`. ########## datafusion/ffi/src/table_provider_factory.rs: ########## @@ -0,0 +1,492 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +use std::{ffi::c_void, sync::Arc}; + +use abi_stable::{ + StableAbi, + std_types::{RResult, RString, RVec}, +}; +use async_ffi::{FfiFuture, FutureExt}; +use async_trait::async_trait; +use datafusion_catalog::{Session, TableProvider, TableProviderFactory}; +use datafusion_common::TableReference; +use datafusion_common::error::{DataFusionError, Result}; +use datafusion_execution::TaskContext; +use datafusion_expr::CreateExternalTable; +use datafusion_proto::logical_plan::from_proto::{parse_expr, parse_sorts}; +use datafusion_proto::logical_plan::to_proto::{serialize_expr, serialize_sorts}; +use datafusion_proto::logical_plan::{ + DefaultLogicalExtensionCodec, LogicalExtensionCodec, +}; +use datafusion_proto::protobuf::{CreateExternalTableNode, SortExprNodeCollection}; +use prost::Message; +use std::collections::HashMap; +use tokio::runtime::Handle; + +use crate::execution::FFI_TaskContextProvider; +use crate::proto::logical_extension_codec::FFI_LogicalExtensionCodec; +use crate::session::{FFI_SessionRef, ForeignSession}; +use crate::table_provider::{FFI_TableProvider, ForeignTableProvider}; +use crate::{df_result, rresult_return}; + +/// A stable struct for sharing [`TableProviderFactory`] across FFI boundaries. +/// +/// Similar to [`FFI_TableProvider`], this struct uses the FFI-safe pattern where: +/// - The `FFI_*` struct exposes stable function pointers +/// - Private data is stored as an opaque pointer +/// - The `Foreign*` wrapper is used by consumers on the other side of the FFI boundary +/// +/// [`FFI_TableProvider`]: crate::table_provider::FFI_TableProvider +#[repr(C)] +#[derive(Debug, StableAbi)] +pub struct FFI_TableProviderFactory { + /// Create a TableProvider with the given command. + /// + /// # Arguments + /// + /// * `factory` - the table provider factory + /// * `session_config` - session configuration + /// * `cmd_serialized` - a [`CreateExternalTableNode`] protobuf message serialized into bytes + /// to pass across the FFI boundary. + create: unsafe extern "C" fn( + factory: &Self, + session: FFI_SessionRef, + cmd_serialized: RVec<u8>, + ) -> FfiFuture<RResult<FFI_TableProvider, RString>>, + + pub logical_codec: FFI_LogicalExtensionCodec, + + /// Used to create a clone of the factory. This should only need to be called + /// by the receiver of the factory. + pub clone: unsafe extern "C" fn(factory: &Self) -> Self, + + /// Release the memory of the private data when it is no longer being used. + pub release: unsafe extern "C" fn(factory: &mut Self), + + /// Return the major DataFusion version number of this factory. + pub version: unsafe extern "C" fn() -> u64, + + /// Internal data. This is only to be accessed by the provider of the factory. + /// A [`ForeignTableProviderFactory`] should never attempt to access this data. + pub private_data: *mut c_void, + + /// Utility to identify when FFI objects are accessed locally through + /// the foreign interface. See [`crate::get_library_marker_id`] and + /// the crate's `README.md` for more information. + pub library_marker_id: extern "C" fn() -> usize, +} + +unsafe impl Send for FFI_TableProviderFactory {} +unsafe impl Sync for FFI_TableProviderFactory {} + +struct FactoryPrivateData { + factory: Arc<dyn TableProviderFactory + Send>, + runtime: Option<Handle>, +} + +impl FFI_TableProviderFactory { + /// Creates a new [`FFI_TableProvider`]. + pub fn new( + factory: Arc<dyn TableProviderFactory + Send>, + runtime: Option<Handle>, + task_ctx_provider: impl Into<FFI_TaskContextProvider>, + logical_codec: Option<Arc<dyn LogicalExtensionCodec>>, + ) -> Self { + let task_ctx_provider = task_ctx_provider.into(); + let logical_codec = + logical_codec.unwrap_or_else(|| Arc::new(DefaultLogicalExtensionCodec {})); + let logical_codec = FFI_LogicalExtensionCodec::new( + logical_codec, + runtime.clone(), + task_ctx_provider.clone(), + ); + Self::new_with_ffi_codec(factory, runtime, logical_codec) + } + + pub fn new_with_ffi_codec( + factory: Arc<dyn TableProviderFactory + Send>, + runtime: Option<Handle>, + logical_codec: FFI_LogicalExtensionCodec, + ) -> Self { + let private_data = Box::new(FactoryPrivateData { factory, runtime }); + + Self { + create: create_fn_wrapper, + logical_codec, + clone: clone_fn_wrapper, + release: release_fn_wrapper, + version: super::version, + private_data: Box::into_raw(private_data) as *mut c_void, + library_marker_id: crate::get_library_marker_id, + } + } + + fn inner(&self) -> &Arc<dyn TableProviderFactory + Send> { + let private_data = self.private_data as *const FactoryPrivateData; + unsafe { &(*private_data).factory } + } + + fn runtime(&self) -> &Option<Handle> { + let private_data = self.private_data as *const FactoryPrivateData; + unsafe { &(*private_data).runtime } + } +} + +impl Clone for FFI_TableProviderFactory { + fn clone(&self) -> Self { + unsafe { (self.clone)(self) } + } +} + +impl Drop for FFI_TableProviderFactory { + fn drop(&mut self) { + unsafe { (self.release)(self) } + } +} + +unsafe extern "C" fn create_fn_wrapper( + factory: &FFI_TableProviderFactory, + session: FFI_SessionRef, + cmd_serialized: RVec<u8>, +) -> FfiFuture<RResult<FFI_TableProvider, RString>> { + let task_ctx: Result<Arc<TaskContext>, DataFusionError> = + (&factory.logical_codec.task_ctx_provider).try_into(); + let runtime = factory.runtime().clone(); + let logical_codec: Arc<dyn LogicalExtensionCodec> = (&factory.logical_codec).into(); + let ffi_logical_codec = factory.logical_codec.clone(); + let internal_factory = Arc::clone(factory.inner()); + + async move { + let mut foreign_session = None; + let session = rresult_return!( + session + .as_local() + .map(Ok::<&(dyn Session + Send + Sync), DataFusionError>) + .unwrap_or_else(|| { + foreign_session = Some(ForeignSession::try_from(&session)?); + Ok(foreign_session.as_ref().unwrap()) + }) + ); + + let task_ctx = rresult_return!(task_ctx); + + let proto_cmd = + rresult_return!(CreateExternalTableNode::decode(cmd_serialized.as_ref())); + + // Deserialize CreateExternalTable from protobuf + let pb_schema = rresult_return!(proto_cmd.schema.ok_or_else(|| { + DataFusionError::Internal( + "CreateExternalTableNode was missing required field schema".to_string(), + ) + })); + + let constraints = rresult_return!(proto_cmd.constraints.ok_or_else(|| { + DataFusionError::Internal( + "CreateExternalTableNode was missing required field constraints" + .to_string(), + ) + })); + + let definition = if !proto_cmd.definition.is_empty() { + Some(proto_cmd.definition) + } else { + None + }; + + let mut order_exprs = Vec::with_capacity(proto_cmd.order_exprs.len()); + for expr in &proto_cmd.order_exprs { + let sorts = rresult_return!(parse_sorts( + &expr.sort_expr_nodes, + task_ctx.as_ref(), + logical_codec.as_ref(), + )); + order_exprs.push(sorts); + } + + let mut column_defaults = HashMap::with_capacity(proto_cmd.column_defaults.len()); + for (col_name, expr) in &proto_cmd.column_defaults { + let expr = rresult_return!(parse_expr( + expr, + task_ctx.as_ref(), + logical_codec.as_ref() + )); + column_defaults.insert(col_name.clone(), expr); + } + + let table_ref = rresult_return!(proto_cmd.name.as_ref().ok_or_else(|| { + DataFusionError::Internal( + "CreateExternalTableNode was missing required field name".to_string(), + ) + })); + + let name: TableReference = rresult_return!(table_ref.clone().try_into()); + + let cmd = CreateExternalTable { + schema: rresult_return!(pb_schema.try_into()), + name, + location: proto_cmd.location, + file_type: proto_cmd.file_type, + table_partition_cols: proto_cmd.table_partition_cols, + order_exprs, + if_not_exists: proto_cmd.if_not_exists, + or_replace: proto_cmd.or_replace, + temporary: proto_cmd.temporary, + definition, + unbounded: proto_cmd.unbounded, + options: proto_cmd.options, + constraints: constraints.into(), + column_defaults, + }; + + let provider = rresult_return!(internal_factory.create(session, &cmd).await); + + RResult::ROk(FFI_TableProvider::new_with_ffi_codec( + provider, + true, + runtime.clone(), + ffi_logical_codec, + )) + } + .into_ffi() +} + +unsafe extern "C" fn clone_fn_wrapper( + factory: &FFI_TableProviderFactory, +) -> FFI_TableProviderFactory { + let runtime = factory.runtime().clone(); + let old_factory = Arc::clone(factory.inner()); + + let private_data = Box::into_raw(Box::new(FactoryPrivateData { + factory: old_factory, + runtime, + })) as *mut c_void; + + FFI_TableProviderFactory { + create: create_fn_wrapper, + logical_codec: factory.logical_codec.clone(), + clone: clone_fn_wrapper, + release: release_fn_wrapper, + version: super::version, + private_data, + library_marker_id: crate::get_library_marker_id, + } +} + +unsafe extern "C" fn release_fn_wrapper(factory: &mut FFI_TableProviderFactory) { + unsafe { + debug_assert!(!factory.private_data.is_null()); + let private_data = Box::from_raw(factory.private_data as *mut FactoryPrivateData); + drop(private_data); + factory.private_data = std::ptr::null_mut(); + } +} + +/// This wrapper struct exists on the receiver side of the FFI interface, so it has +/// no guarantees about being able to access the data in `private_data`. Any functions +/// defined on this struct must only use the stable functions provided in +/// FFI_TableProviderFactory to interact with the foreign table provider factory. +#[derive(Debug)] +pub struct ForeignTableProviderFactory(pub FFI_TableProviderFactory); + +impl From<&FFI_TableProviderFactory> for Arc<dyn TableProviderFactory> { + fn from(factory: &FFI_TableProviderFactory) -> Self { + if (factory.library_marker_id)() == crate::get_library_marker_id() { + Arc::clone(factory.inner()) as Arc<dyn TableProviderFactory> + } else { + Arc::new(ForeignTableProviderFactory(factory.clone())) + } + } +} + +unsafe impl Send for ForeignTableProviderFactory {} +unsafe impl Sync for ForeignTableProviderFactory {} + +#[async_trait] +impl TableProviderFactory for ForeignTableProviderFactory { + async fn create( + &self, + session: &dyn Session, + cmd: &CreateExternalTable, + ) -> Result<Arc<dyn TableProvider>> { + let session = FFI_SessionRef::new(session, None, self.0.logical_codec.clone()); + + let codec: Arc<dyn LogicalExtensionCodec> = (&self.0.logical_codec).into(); + + // Serialize CreateExternalTable to protobuf + let mut converted_order_exprs: Vec<SortExprNodeCollection> = vec![]; + for order in &cmd.order_exprs { + let temp = SortExprNodeCollection { + sort_expr_nodes: serialize_sorts(order, codec.as_ref())?, + }; + converted_order_exprs.push(temp); + } + + let mut converted_column_defaults = + HashMap::with_capacity(cmd.column_defaults.len()); + for (col_name, expr) in &cmd.column_defaults { + converted_column_defaults + .insert(col_name.clone(), serialize_expr(expr, codec.as_ref())?); + } + + let proto_cmd = CreateExternalTableNode { + name: Some(cmd.name.clone().into()), + location: cmd.location.clone(), + file_type: cmd.file_type.clone(), + schema: Some(cmd.schema.as_ref().try_into()?), + table_partition_cols: cmd.table_partition_cols.clone(), + if_not_exists: cmd.if_not_exists, + or_replace: cmd.or_replace, + temporary: cmd.temporary, + order_exprs: converted_order_exprs, + definition: cmd.definition.clone().unwrap_or_default(), + unbounded: cmd.unbounded, + options: cmd.options.clone(), + constraints: Some(cmd.constraints.clone().into()), + column_defaults: converted_column_defaults, + }; + + let cmd_serialized = proto_cmd.encode_to_vec().into(); + + let provider = unsafe { + let maybe_provider = (self.0.create)(&self.0, session, cmd_serialized).await; + + let ffi_provider = df_result!(maybe_provider)?; + ForeignTableProvider(ffi_provider) + }; + + Ok(Arc::new(provider)) + } +} + +#[cfg(test)] +mod tests { + use arrow::datatypes::Schema; + use datafusion::prelude::SessionContext; + use datafusion_common::ToDFSchema; + use datafusion_execution::TaskContextProvider; + use std::collections::HashMap; + + use super::*; + + #[derive(Debug)] + struct TestTableProviderFactory {} + + #[async_trait] + impl TableProviderFactory for TestTableProviderFactory { + async fn create( + &self, + _session: &dyn Session, + _cmd: &CreateExternalTable, Review Comment: Since this PR does include the proto conversion back and forth of the command, we probably want to at least test this command in some way. -- This is an automated message from the Apache Git Service. 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