[GitHub] [arrow-rs] sunchao commented on a change in pull request #1384: Add FFI for Arrow C Stream Interface

[GitBox <gi...@apache.org>]

sunchao commented on a change in pull request #1384:
URL: https://github.com/apache/arrow-rs/pull/1384#discussion_r821381095



##########
File path: arrow/src/ffi_stream.rs
##########
@@ -0,0 +1,515 @@
+// 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.
+
+//! Contains declarations to bind to the [C Stream Interface](https://arrow.apache.org/docs/format/CStreamInterface.html).

Review comment:
       can we add some rust doc on how this is going to be used? we can follow example in `src/ffi.rs`.

##########
File path: arrow/src/ffi_stream.rs
##########
@@ -0,0 +1,515 @@
+// 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.
+
+//! Contains declarations to bind to the [C Stream Interface](https://arrow.apache.org/docs/format/CStreamInterface.html).
+//!
+
+use std::{
+    convert::TryFrom,
+    ffi::CString,
+    os::raw::{c_char, c_int, c_void},
+    sync::Arc,
+};
+
+use crate::array::Array;
+use crate::array::StructArray;
+use crate::datatypes::{Schema, SchemaRef};
+use crate::error::ArrowError;
+use crate::error::Result;
+use crate::ffi::*;
+use crate::record_batch::{RecordBatch, RecordBatchReader};
+
+const ENOMEM: i32 = 12;
+const EIO: i32 = 5;
+const EINVAL: i32 = 22;
+const ENOSYS: i32 = 78;
+
+/// ABI-compatible struct for `ArrayStream` from C Stream Interface
+/// This interface is experimental
+/// See <https://arrow.apache.org/docs/format/CStreamInterface.html#structure-definitions>
+/// This was created by bindgen
+#[repr(C)]
+#[derive(Debug, Clone)]
+pub struct FFI_ArrowArrayStream {
+    pub get_schema: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowSchema,
+        ) -> c_int,
+    >,
+    pub get_next: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowArray,
+        ) -> c_int,
+    >,
+    pub get_last_error:
+        Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream) -> *const c_char>,
+    pub release: Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream)>,
+    pub private_data: *mut c_void,
+}
+
+// callback used to drop [FFI_ArrowArrayStream] when it is exported.
+unsafe extern "C" fn release_stream(stream: *mut FFI_ArrowArrayStream) {
+    if stream.is_null() {
+        return;
+    }
+    let stream = &mut *stream;
+
+    stream.get_schema = None;
+    stream.get_next = None;
+    stream.get_last_error = None;
+
+    let private_data = Box::from_raw(stream.private_data as *mut StreamPrivateData);
+    drop(private_data);
+
+    stream.release = None;
+}
+
+struct StreamPrivateData {
+    batch_reader: Box<dyn RecordBatchReader>,
+    last_error: String,
+}
+
+// The callback used to get array schema
+unsafe extern "C" fn get_schema(
+    stream: *mut FFI_ArrowArrayStream,
+    schema: *mut FFI_ArrowSchema,
+) -> c_int {
+    ExportedArrayStream { stream }.get_schema(schema)
+}
+
+// The callback used to get next array
+unsafe extern "C" fn get_next(
+    stream: *mut FFI_ArrowArrayStream,
+    array: *mut FFI_ArrowArray,
+) -> c_int {
+    ExportedArrayStream { stream }.get_next(array)
+}
+
+// The callback used to get the error from last operation on the `FFI_ArrowArrayStream`
+unsafe extern "C" fn get_last_error(stream: *mut FFI_ArrowArrayStream) -> *const c_char {
+    let last_error = ExportedArrayStream { stream }.get_last_error();
+    CString::new(last_error.as_str()).unwrap().into_raw()
+}
+
+impl Drop for FFI_ArrowArrayStream {
+    fn drop(&mut self) {
+        match self.release {
+            None => (),
+            Some(release) => unsafe { release(self) },
+        };
+    }
+}
+
+impl FFI_ArrowArrayStream {
+    /// create a new [`FFI_ArrowArrayStream`].
+    pub fn new(batch_reader: Box<dyn RecordBatchReader>) -> Self {
+        let private_data = Box::new(StreamPrivateData {
+            batch_reader,
+            last_error: String::new(),
+        });
+
+        Self {
+            get_schema: Some(get_schema),
+            get_next: Some(get_next),
+            get_last_error: Some(get_last_error),
+            release: Some(release_stream),
+            private_data: Box::into_raw(private_data) as *mut c_void,
+        }
+    }
+
+    pub fn empty() -> Self {

Review comment:
       some comments will be helpful since it's public

##########
File path: arrow/src/ffi_stream.rs
##########
@@ -0,0 +1,515 @@
+// 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.
+
+//! Contains declarations to bind to the [C Stream Interface](https://arrow.apache.org/docs/format/CStreamInterface.html).
+//!
+
+use std::{
+    convert::TryFrom,
+    ffi::CString,
+    os::raw::{c_char, c_int, c_void},
+    sync::Arc,
+};
+
+use crate::array::Array;
+use crate::array::StructArray;
+use crate::datatypes::{Schema, SchemaRef};
+use crate::error::ArrowError;
+use crate::error::Result;
+use crate::ffi::*;
+use crate::record_batch::{RecordBatch, RecordBatchReader};
+
+const ENOMEM: i32 = 12;
+const EIO: i32 = 5;
+const EINVAL: i32 = 22;
+const ENOSYS: i32 = 78;
+
+/// ABI-compatible struct for `ArrayStream` from C Stream Interface
+/// This interface is experimental
+/// See <https://arrow.apache.org/docs/format/CStreamInterface.html#structure-definitions>
+/// This was created by bindgen
+#[repr(C)]
+#[derive(Debug, Clone)]
+pub struct FFI_ArrowArrayStream {
+    pub get_schema: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowSchema,
+        ) -> c_int,
+    >,
+    pub get_next: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowArray,
+        ) -> c_int,
+    >,
+    pub get_last_error:
+        Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream) -> *const c_char>,
+    pub release: Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream)>,
+    pub private_data: *mut c_void,
+}
+
+// callback used to drop [FFI_ArrowArrayStream] when it is exported.
+unsafe extern "C" fn release_stream(stream: *mut FFI_ArrowArrayStream) {
+    if stream.is_null() {
+        return;
+    }
+    let stream = &mut *stream;
+
+    stream.get_schema = None;
+    stream.get_next = None;
+    stream.get_last_error = None;
+
+    let private_data = Box::from_raw(stream.private_data as *mut StreamPrivateData);
+    drop(private_data);
+
+    stream.release = None;
+}
+
+struct StreamPrivateData {
+    batch_reader: Box<dyn RecordBatchReader>,
+    last_error: String,
+}
+
+// The callback used to get array schema
+unsafe extern "C" fn get_schema(
+    stream: *mut FFI_ArrowArrayStream,
+    schema: *mut FFI_ArrowSchema,
+) -> c_int {
+    ExportedArrayStream { stream }.get_schema(schema)
+}
+
+// The callback used to get next array
+unsafe extern "C" fn get_next(
+    stream: *mut FFI_ArrowArrayStream,
+    array: *mut FFI_ArrowArray,
+) -> c_int {
+    ExportedArrayStream { stream }.get_next(array)
+}
+
+// The callback used to get the error from last operation on the `FFI_ArrowArrayStream`
+unsafe extern "C" fn get_last_error(stream: *mut FFI_ArrowArrayStream) -> *const c_char {
+    let last_error = ExportedArrayStream { stream }.get_last_error();
+    CString::new(last_error.as_str()).unwrap().into_raw()
+}
+
+impl Drop for FFI_ArrowArrayStream {
+    fn drop(&mut self) {
+        match self.release {
+            None => (),
+            Some(release) => unsafe { release(self) },
+        };
+    }
+}
+
+impl FFI_ArrowArrayStream {
+    /// create a new [`FFI_ArrowArrayStream`].
+    pub fn new(batch_reader: Box<dyn RecordBatchReader>) -> Self {
+        let private_data = Box::new(StreamPrivateData {
+            batch_reader,
+            last_error: String::new(),
+        });
+
+        Self {
+            get_schema: Some(get_schema),
+            get_next: Some(get_next),
+            get_last_error: Some(get_last_error),
+            release: Some(release_stream),
+            private_data: Box::into_raw(private_data) as *mut c_void,
+        }
+    }
+
+    pub fn empty() -> Self {
+        Self {
+            get_schema: None,
+            get_next: None,
+            get_last_error: None,
+            release: None,
+            private_data: std::ptr::null_mut(),
+        }
+    }
+
+    pub fn to_raw(this: Arc<FFI_ArrowArrayStream>) -> *const FFI_ArrowArrayStream {
+        Arc::into_raw(this)
+    }
+
+    /// Get `FFI_ArrowArrayStream` from raw pointer
+    /// # Safety
+    /// Assumes that the pointer represents valid C Stream Interfaces, both in memory
+    /// representation and lifetime via the `release` mechanism.
+    pub unsafe fn from_raw(
+        ptr: *const FFI_ArrowArrayStream,
+    ) -> Arc<FFI_ArrowArrayStream> {
+        let ffi_stream = (*ptr).clone();
+        Arc::new(ffi_stream)
+    }
+}
+
+struct ExportedArrayStream {
+    stream: *mut FFI_ArrowArrayStream,
+}
+
+impl ExportedArrayStream {
+    fn get_private_data(&self) -> Box<StreamPrivateData> {
+        unsafe { Box::from_raw((*self.stream).private_data as *mut StreamPrivateData) }
+    }
+
+    pub fn get_schema(&self, out: *mut FFI_ArrowSchema) -> i32 {
+        unsafe {
+            match (*out).release {
+                None => (),
+                Some(release) => release(out),
+            };
+        };
+
+        let mut private_data = self.get_private_data();
+        let reader = &private_data.batch_reader;
+
+        let schema = FFI_ArrowSchema::try_from(reader.schema().as_ref());
+
+        let ret_code = match schema {
+            Ok(mut schema) => {
+                unsafe {
+                    (*out).format = schema.format;
+                    (*out).name = schema.name;
+                    (*out).metadata = schema.metadata;
+                    (*out).flags = schema.flags;
+                    (*out).n_children = schema.n_children;
+                    (*out).children = schema.children;
+                    (*out).dictionary = schema.dictionary;
+                    (*out).release = schema.release;
+                    (*out).private_data = schema.private_data;
+                }
+                schema.release = None;
+                0
+            }
+            Err(ref err) => {
+                private_data.last_error = err.to_string();
+                get_error_code(err)
+            }
+        };
+
+        Box::into_raw(private_data);
+        ret_code
+    }
+
+    pub fn get_next(&self, out: *mut FFI_ArrowArray) -> i32 {
+        unsafe {
+            match (*out).release {
+                None => (),
+                Some(release) => release(out),
+            };
+        };
+
+        let mut private_data = self.get_private_data();
+        let reader = &mut private_data.batch_reader;
+
+        let ret_code = match reader.next() {
+            None => 0,
+            Some(next_batch) => {
+                if let Ok(batch) = next_batch {
+                    let struct_array = StructArray::from(batch);
+                    let mut array = FFI_ArrowArray::new(struct_array.data());
+
+                    unsafe {
+                        (*out).length = array.length;
+                        (*out).null_count = array.null_count;
+                        (*out).offset = array.offset;
+                        (*out).n_buffers = array.n_buffers;
+                        (*out).n_children = array.n_children;
+                        (*out).buffers = array.buffers;
+                        (*out).children = array.children;
+                        (*out).dictionary = array.dictionary;
+                        (*out).release = array.release;
+                        (*out).private_data = array.private_data;
+                    }
+
+                    array.release = None;
+                    0
+                } else {
+                    let err = &next_batch.unwrap_err();
+                    private_data.last_error = err.to_string();
+                    get_error_code(err)
+                }
+            }
+        };
+
+        Box::into_raw(private_data);
+        ret_code
+    }
+
+    pub fn get_last_error(&self) -> String {
+        self.get_private_data().last_error
+    }
+}
+
+fn get_error_code(err: &ArrowError) -> i32 {
+    match err {
+        ArrowError::NotYetImplemented(_) => ENOSYS,
+        ArrowError::MemoryError(_) => ENOMEM,
+        ArrowError::IoError(_) => EIO,
+        _ => EINVAL,
+    }
+}
+
+/// A `RecordBatch` reader which imports from `FFI_ArrowArrayStream`
+struct ArrowArrayStreamReader {
+    stream: Arc<FFI_ArrowArrayStream>,
+}
+
+impl ArrowArrayStreamReader {
+    #[allow(dead_code)]
+    pub fn new(stream: FFI_ArrowArrayStream) -> Self {
+        Self {
+            stream: Arc::new(stream),
+        }
+    }
+
+    #[allow(dead_code)]
+    pub fn from_raw(raw_stream: *mut FFI_ArrowArrayStream) -> Self {
+        let stream = unsafe { Arc::new((*raw_stream).clone()) };
+        Self { stream }
+    }
+}
+
+/// Get the last error from `ArrowArrayStreamReader`
+fn get_stream_last_error(stream_reader: &ArrowArrayStreamReader) -> Option<String> {

Review comment:
       can this be a method of `ArrowArrayStreamReader`?

##########
File path: arrow/src/ffi_stream.rs
##########
@@ -0,0 +1,515 @@
+// 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.
+
+//! Contains declarations to bind to the [C Stream Interface](https://arrow.apache.org/docs/format/CStreamInterface.html).
+//!
+
+use std::{
+    convert::TryFrom,
+    ffi::CString,
+    os::raw::{c_char, c_int, c_void},
+    sync::Arc,
+};
+
+use crate::array::Array;
+use crate::array::StructArray;
+use crate::datatypes::{Schema, SchemaRef};
+use crate::error::ArrowError;
+use crate::error::Result;
+use crate::ffi::*;
+use crate::record_batch::{RecordBatch, RecordBatchReader};
+
+const ENOMEM: i32 = 12;
+const EIO: i32 = 5;
+const EINVAL: i32 = 22;
+const ENOSYS: i32 = 78;
+
+/// ABI-compatible struct for `ArrayStream` from C Stream Interface
+/// This interface is experimental
+/// See <https://arrow.apache.org/docs/format/CStreamInterface.html#structure-definitions>
+/// This was created by bindgen
+#[repr(C)]
+#[derive(Debug, Clone)]
+pub struct FFI_ArrowArrayStream {
+    pub get_schema: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowSchema,
+        ) -> c_int,
+    >,
+    pub get_next: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowArray,
+        ) -> c_int,
+    >,
+    pub get_last_error:
+        Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream) -> *const c_char>,
+    pub release: Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream)>,
+    pub private_data: *mut c_void,
+}
+
+// callback used to drop [FFI_ArrowArrayStream] when it is exported.
+unsafe extern "C" fn release_stream(stream: *mut FFI_ArrowArrayStream) {
+    if stream.is_null() {
+        return;
+    }
+    let stream = &mut *stream;
+
+    stream.get_schema = None;
+    stream.get_next = None;
+    stream.get_last_error = None;
+
+    let private_data = Box::from_raw(stream.private_data as *mut StreamPrivateData);
+    drop(private_data);
+
+    stream.release = None;
+}
+
+struct StreamPrivateData {
+    batch_reader: Box<dyn RecordBatchReader>,
+    last_error: String,
+}
+
+// The callback used to get array schema
+unsafe extern "C" fn get_schema(
+    stream: *mut FFI_ArrowArrayStream,
+    schema: *mut FFI_ArrowSchema,
+) -> c_int {
+    ExportedArrayStream { stream }.get_schema(schema)
+}
+
+// The callback used to get next array
+unsafe extern "C" fn get_next(
+    stream: *mut FFI_ArrowArrayStream,
+    array: *mut FFI_ArrowArray,
+) -> c_int {
+    ExportedArrayStream { stream }.get_next(array)
+}
+
+// The callback used to get the error from last operation on the `FFI_ArrowArrayStream`
+unsafe extern "C" fn get_last_error(stream: *mut FFI_ArrowArrayStream) -> *const c_char {
+    let last_error = ExportedArrayStream { stream }.get_last_error();
+    CString::new(last_error.as_str()).unwrap().into_raw()
+}
+
+impl Drop for FFI_ArrowArrayStream {
+    fn drop(&mut self) {
+        match self.release {
+            None => (),
+            Some(release) => unsafe { release(self) },
+        };
+    }
+}
+
+impl FFI_ArrowArrayStream {
+    /// create a new [`FFI_ArrowArrayStream`].
+    pub fn new(batch_reader: Box<dyn RecordBatchReader>) -> Self {
+        let private_data = Box::new(StreamPrivateData {
+            batch_reader,
+            last_error: String::new(),
+        });
+
+        Self {
+            get_schema: Some(get_schema),
+            get_next: Some(get_next),
+            get_last_error: Some(get_last_error),
+            release: Some(release_stream),
+            private_data: Box::into_raw(private_data) as *mut c_void,
+        }
+    }
+
+    pub fn empty() -> Self {
+        Self {
+            get_schema: None,
+            get_next: None,
+            get_last_error: None,
+            release: None,
+            private_data: std::ptr::null_mut(),
+        }
+    }
+
+    pub fn to_raw(this: Arc<FFI_ArrowArrayStream>) -> *const FFI_ArrowArrayStream {
+        Arc::into_raw(this)
+    }
+
+    /// Get `FFI_ArrowArrayStream` from raw pointer
+    /// # Safety
+    /// Assumes that the pointer represents valid C Stream Interfaces, both in memory
+    /// representation and lifetime via the `release` mechanism.
+    pub unsafe fn from_raw(
+        ptr: *const FFI_ArrowArrayStream,
+    ) -> Arc<FFI_ArrowArrayStream> {
+        let ffi_stream = (*ptr).clone();
+        Arc::new(ffi_stream)
+    }
+}
+
+struct ExportedArrayStream {
+    stream: *mut FFI_ArrowArrayStream,
+}
+
+impl ExportedArrayStream {
+    fn get_private_data(&self) -> Box<StreamPrivateData> {
+        unsafe { Box::from_raw((*self.stream).private_data as *mut StreamPrivateData) }
+    }
+
+    pub fn get_schema(&self, out: *mut FFI_ArrowSchema) -> i32 {
+        unsafe {
+            match (*out).release {
+                None => (),
+                Some(release) => release(out),
+            };
+        };
+
+        let mut private_data = self.get_private_data();
+        let reader = &private_data.batch_reader;
+
+        let schema = FFI_ArrowSchema::try_from(reader.schema().as_ref());
+
+        let ret_code = match schema {
+            Ok(mut schema) => {
+                unsafe {
+                    (*out).format = schema.format;
+                    (*out).name = schema.name;
+                    (*out).metadata = schema.metadata;
+                    (*out).flags = schema.flags;
+                    (*out).n_children = schema.n_children;
+                    (*out).children = schema.children;
+                    (*out).dictionary = schema.dictionary;
+                    (*out).release = schema.release;
+                    (*out).private_data = schema.private_data;
+                }
+                schema.release = None;
+                0
+            }
+            Err(ref err) => {
+                private_data.last_error = err.to_string();
+                get_error_code(err)
+            }
+        };
+
+        Box::into_raw(private_data);
+        ret_code
+    }
+
+    pub fn get_next(&self, out: *mut FFI_ArrowArray) -> i32 {
+        unsafe {
+            match (*out).release {
+                None => (),
+                Some(release) => release(out),
+            };
+        };
+
+        let mut private_data = self.get_private_data();
+        let reader = &mut private_data.batch_reader;
+
+        let ret_code = match reader.next() {
+            None => 0,
+            Some(next_batch) => {
+                if let Ok(batch) = next_batch {
+                    let struct_array = StructArray::from(batch);
+                    let mut array = FFI_ArrowArray::new(struct_array.data());
+
+                    unsafe {
+                        (*out).length = array.length;
+                        (*out).null_count = array.null_count;
+                        (*out).offset = array.offset;
+                        (*out).n_buffers = array.n_buffers;
+                        (*out).n_children = array.n_children;
+                        (*out).buffers = array.buffers;
+                        (*out).children = array.children;
+                        (*out).dictionary = array.dictionary;
+                        (*out).release = array.release;
+                        (*out).private_data = array.private_data;
+                    }
+
+                    array.release = None;
+                    0
+                } else {
+                    let err = &next_batch.unwrap_err();
+                    private_data.last_error = err.to_string();
+                    get_error_code(err)
+                }
+            }
+        };
+
+        Box::into_raw(private_data);
+        ret_code
+    }
+
+    pub fn get_last_error(&self) -> String {
+        self.get_private_data().last_error
+    }
+}
+
+fn get_error_code(err: &ArrowError) -> i32 {
+    match err {
+        ArrowError::NotYetImplemented(_) => ENOSYS,
+        ArrowError::MemoryError(_) => ENOMEM,
+        ArrowError::IoError(_) => EIO,
+        _ => EINVAL,
+    }
+}
+
+/// A `RecordBatch` reader which imports from `FFI_ArrowArrayStream`
+struct ArrowArrayStreamReader {
+    stream: Arc<FFI_ArrowArrayStream>,
+}
+
+impl ArrowArrayStreamReader {
+    #[allow(dead_code)]
+    pub fn new(stream: FFI_ArrowArrayStream) -> Self {
+        Self {
+            stream: Arc::new(stream),
+        }
+    }
+
+    #[allow(dead_code)]
+    pub fn from_raw(raw_stream: *mut FFI_ArrowArrayStream) -> Self {
+        let stream = unsafe { Arc::new((*raw_stream).clone()) };
+        Self { stream }
+    }
+}
+
+/// Get the last error from `ArrowArrayStreamReader`
+fn get_stream_last_error(stream_reader: &ArrowArrayStreamReader) -> Option<String> {
+    stream_reader.stream.get_last_error?;
+
+    let stream_ptr =
+        Arc::into_raw(stream_reader.stream.clone()) as *mut FFI_ArrowArrayStream;
+
+    let error_str = unsafe {
+        let c_str =
+            stream_reader.stream.get_last_error.unwrap()(stream_ptr) as *mut c_char;
+        CString::from_raw(c_str).into_string()
+    };
+
+    if let Err(err) = error_str {
+        Some(err.to_string())
+    } else {
+        Some(error_str.unwrap())
+    }
+}
+
+impl Iterator for ArrowArrayStreamReader {
+    type Item = Result<RecordBatch>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.stream.get_next?;
+
+        let stream_ptr = Arc::into_raw(self.stream.clone()) as *mut FFI_ArrowArrayStream;
+
+        let empty_array = Arc::new(FFI_ArrowArray::empty());
+        let array_ptr = Arc::into_raw(empty_array) as *mut FFI_ArrowArray;
+
+        let ret_code = unsafe { self.stream.get_next.unwrap()(stream_ptr, array_ptr) };
+
+        let ffi_array = unsafe { Arc::from_raw(array_ptr) };
+
+        // The end of stream has been reached
+        ffi_array.release?;
+
+        let schema_ref = self.schema();
+        let schema = FFI_ArrowSchema::try_from(schema_ref.as_ref());
+
+        if schema.is_err() {
+            return Some(Err(schema.err().unwrap()));
+        }
+
+        if ret_code == 0 {
+            let data = ArrowArray {
+                array: ffi_array,
+                schema: Arc::new(schema.unwrap()),
+            }
+            .to_data();
+
+            if data.is_err() {
+                return Some(Err(data.err().unwrap()));
+            }
+
+            let record_batch = RecordBatch::from(&StructArray::from(data.unwrap()));
+
+            Some(Ok(record_batch))
+        } else {
+            let last_error = get_stream_last_error(self);
+            let err = ArrowError::CDataInterface(last_error.unwrap());
+            Some(Err(err))
+        }
+    }
+}
+
+impl RecordBatchReader for ArrowArrayStreamReader {
+    fn schema(&self) -> SchemaRef {
+        if self.stream.get_schema.is_none() {
+            return Arc::new(Schema::empty());
+        }
+
+        let stream_ptr = Arc::into_raw(self.stream.clone()) as *mut FFI_ArrowArrayStream;
+
+        let empty_schema = Arc::new(FFI_ArrowSchema::empty());
+        let schema_ptr = Arc::into_raw(empty_schema) as *mut FFI_ArrowSchema;
+
+        let ret_code = unsafe { self.stream.get_schema.unwrap()(stream_ptr, schema_ptr) };
+
+        let ffi_schema = unsafe { Arc::from_raw(schema_ptr) };
+
+        if ret_code == 0 {
+            let schema = Schema::try_from(ffi_schema.as_ref()).unwrap();
+            Arc::new(schema)
+        } else {
+            Arc::new(Schema::empty())
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {

Review comment:
       maybe we should have some integration tests between Python and Rust too in `arrow-pyarrow-integration-testing`.

##########
File path: arrow/src/ffi_stream.rs
##########
@@ -0,0 +1,515 @@
+// 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.
+
+//! Contains declarations to bind to the [C Stream Interface](https://arrow.apache.org/docs/format/CStreamInterface.html).
+//!
+
+use std::{
+    convert::TryFrom,
+    ffi::CString,
+    os::raw::{c_char, c_int, c_void},
+    sync::Arc,
+};
+
+use crate::array::Array;
+use crate::array::StructArray;
+use crate::datatypes::{Schema, SchemaRef};
+use crate::error::ArrowError;
+use crate::error::Result;
+use crate::ffi::*;
+use crate::record_batch::{RecordBatch, RecordBatchReader};
+
+const ENOMEM: i32 = 12;
+const EIO: i32 = 5;
+const EINVAL: i32 = 22;
+const ENOSYS: i32 = 78;
+
+/// ABI-compatible struct for `ArrayStream` from C Stream Interface
+/// This interface is experimental
+/// See <https://arrow.apache.org/docs/format/CStreamInterface.html#structure-definitions>
+/// This was created by bindgen
+#[repr(C)]
+#[derive(Debug, Clone)]
+pub struct FFI_ArrowArrayStream {
+    pub get_schema: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowSchema,
+        ) -> c_int,
+    >,
+    pub get_next: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowArray,
+        ) -> c_int,
+    >,
+    pub get_last_error:
+        Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream) -> *const c_char>,
+    pub release: Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream)>,
+    pub private_data: *mut c_void,
+}
+
+// callback used to drop [FFI_ArrowArrayStream] when it is exported.
+unsafe extern "C" fn release_stream(stream: *mut FFI_ArrowArrayStream) {
+    if stream.is_null() {
+        return;
+    }
+    let stream = &mut *stream;
+
+    stream.get_schema = None;
+    stream.get_next = None;
+    stream.get_last_error = None;
+
+    let private_data = Box::from_raw(stream.private_data as *mut StreamPrivateData);
+    drop(private_data);
+
+    stream.release = None;
+}
+
+struct StreamPrivateData {
+    batch_reader: Box<dyn RecordBatchReader>,
+    last_error: String,
+}
+
+// The callback used to get array schema
+unsafe extern "C" fn get_schema(
+    stream: *mut FFI_ArrowArrayStream,
+    schema: *mut FFI_ArrowSchema,
+) -> c_int {
+    ExportedArrayStream { stream }.get_schema(schema)
+}
+
+// The callback used to get next array
+unsafe extern "C" fn get_next(
+    stream: *mut FFI_ArrowArrayStream,
+    array: *mut FFI_ArrowArray,
+) -> c_int {
+    ExportedArrayStream { stream }.get_next(array)
+}
+
+// The callback used to get the error from last operation on the `FFI_ArrowArrayStream`
+unsafe extern "C" fn get_last_error(stream: *mut FFI_ArrowArrayStream) -> *const c_char {
+    let last_error = ExportedArrayStream { stream }.get_last_error();
+    CString::new(last_error.as_str()).unwrap().into_raw()
+}
+
+impl Drop for FFI_ArrowArrayStream {
+    fn drop(&mut self) {
+        match self.release {
+            None => (),
+            Some(release) => unsafe { release(self) },
+        };
+    }
+}
+
+impl FFI_ArrowArrayStream {
+    /// create a new [`FFI_ArrowArrayStream`].
+    pub fn new(batch_reader: Box<dyn RecordBatchReader>) -> Self {
+        let private_data = Box::new(StreamPrivateData {
+            batch_reader,
+            last_error: String::new(),
+        });
+
+        Self {
+            get_schema: Some(get_schema),
+            get_next: Some(get_next),
+            get_last_error: Some(get_last_error),
+            release: Some(release_stream),
+            private_data: Box::into_raw(private_data) as *mut c_void,
+        }
+    }
+
+    pub fn empty() -> Self {
+        Self {
+            get_schema: None,
+            get_next: None,
+            get_last_error: None,
+            release: None,
+            private_data: std::ptr::null_mut(),
+        }
+    }
+
+    pub fn to_raw(this: Arc<FFI_ArrowArrayStream>) -> *const FFI_ArrowArrayStream {
+        Arc::into_raw(this)
+    }
+
+    /// Get `FFI_ArrowArrayStream` from raw pointer
+    /// # Safety
+    /// Assumes that the pointer represents valid C Stream Interfaces, both in memory
+    /// representation and lifetime via the `release` mechanism.
+    pub unsafe fn from_raw(
+        ptr: *const FFI_ArrowArrayStream,
+    ) -> Arc<FFI_ArrowArrayStream> {
+        let ffi_stream = (*ptr).clone();
+        Arc::new(ffi_stream)
+    }
+}
+
+struct ExportedArrayStream {
+    stream: *mut FFI_ArrowArrayStream,
+}
+
+impl ExportedArrayStream {
+    fn get_private_data(&self) -> Box<StreamPrivateData> {
+        unsafe { Box::from_raw((*self.stream).private_data as *mut StreamPrivateData) }
+    }
+
+    pub fn get_schema(&self, out: *mut FFI_ArrowSchema) -> i32 {
+        unsafe {
+            match (*out).release {
+                None => (),
+                Some(release) => release(out),
+            };
+        };
+
+        let mut private_data = self.get_private_data();
+        let reader = &private_data.batch_reader;
+
+        let schema = FFI_ArrowSchema::try_from(reader.schema().as_ref());
+
+        let ret_code = match schema {
+            Ok(mut schema) => {
+                unsafe {
+                    (*out).format = schema.format;
+                    (*out).name = schema.name;
+                    (*out).metadata = schema.metadata;
+                    (*out).flags = schema.flags;
+                    (*out).n_children = schema.n_children;
+                    (*out).children = schema.children;
+                    (*out).dictionary = schema.dictionary;
+                    (*out).release = schema.release;
+                    (*out).private_data = schema.private_data;
+                }
+                schema.release = None;
+                0
+            }
+            Err(ref err) => {
+                private_data.last_error = err.to_string();
+                get_error_code(err)
+            }
+        };
+
+        Box::into_raw(private_data);
+        ret_code
+    }
+
+    pub fn get_next(&self, out: *mut FFI_ArrowArray) -> i32 {
+        unsafe {
+            match (*out).release {
+                None => (),
+                Some(release) => release(out),
+            };
+        };
+
+        let mut private_data = self.get_private_data();
+        let reader = &mut private_data.batch_reader;
+
+        let ret_code = match reader.next() {
+            None => 0,
+            Some(next_batch) => {
+                if let Ok(batch) = next_batch {
+                    let struct_array = StructArray::from(batch);
+                    let mut array = FFI_ArrowArray::new(struct_array.data());
+
+                    unsafe {
+                        (*out).length = array.length;
+                        (*out).null_count = array.null_count;
+                        (*out).offset = array.offset;
+                        (*out).n_buffers = array.n_buffers;
+                        (*out).n_children = array.n_children;
+                        (*out).buffers = array.buffers;
+                        (*out).children = array.children;
+                        (*out).dictionary = array.dictionary;
+                        (*out).release = array.release;
+                        (*out).private_data = array.private_data;
+                    }
+
+                    array.release = None;
+                    0
+                } else {
+                    let err = &next_batch.unwrap_err();
+                    private_data.last_error = err.to_string();
+                    get_error_code(err)
+                }
+            }
+        };
+
+        Box::into_raw(private_data);
+        ret_code
+    }
+
+    pub fn get_last_error(&self) -> String {
+        self.get_private_data().last_error
+    }
+}
+
+fn get_error_code(err: &ArrowError) -> i32 {
+    match err {
+        ArrowError::NotYetImplemented(_) => ENOSYS,
+        ArrowError::MemoryError(_) => ENOMEM,
+        ArrowError::IoError(_) => EIO,
+        _ => EINVAL,
+    }
+}
+
+/// A `RecordBatch` reader which imports from `FFI_ArrowArrayStream`
+struct ArrowArrayStreamReader {
+    stream: Arc<FFI_ArrowArrayStream>,
+}
+
+impl ArrowArrayStreamReader {
+    #[allow(dead_code)]
+    pub fn new(stream: FFI_ArrowArrayStream) -> Self {

Review comment:
       maybe check if the input stream has already been released.

##########
File path: arrow/src/ffi_stream.rs
##########
@@ -0,0 +1,515 @@
+// 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.
+
+//! Contains declarations to bind to the [C Stream Interface](https://arrow.apache.org/docs/format/CStreamInterface.html).
+//!
+
+use std::{
+    convert::TryFrom,
+    ffi::CString,
+    os::raw::{c_char, c_int, c_void},
+    sync::Arc,
+};
+
+use crate::array::Array;
+use crate::array::StructArray;
+use crate::datatypes::{Schema, SchemaRef};
+use crate::error::ArrowError;
+use crate::error::Result;
+use crate::ffi::*;
+use crate::record_batch::{RecordBatch, RecordBatchReader};
+
+const ENOMEM: i32 = 12;
+const EIO: i32 = 5;
+const EINVAL: i32 = 22;
+const ENOSYS: i32 = 78;
+
+/// ABI-compatible struct for `ArrayStream` from C Stream Interface
+/// This interface is experimental
+/// See <https://arrow.apache.org/docs/format/CStreamInterface.html#structure-definitions>
+/// This was created by bindgen
+#[repr(C)]
+#[derive(Debug, Clone)]
+pub struct FFI_ArrowArrayStream {
+    pub get_schema: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowSchema,
+        ) -> c_int,
+    >,
+    pub get_next: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowArray,
+        ) -> c_int,
+    >,
+    pub get_last_error:
+        Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream) -> *const c_char>,
+    pub release: Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream)>,
+    pub private_data: *mut c_void,
+}
+
+// callback used to drop [FFI_ArrowArrayStream] when it is exported.
+unsafe extern "C" fn release_stream(stream: *mut FFI_ArrowArrayStream) {
+    if stream.is_null() {
+        return;
+    }
+    let stream = &mut *stream;
+
+    stream.get_schema = None;
+    stream.get_next = None;
+    stream.get_last_error = None;
+
+    let private_data = Box::from_raw(stream.private_data as *mut StreamPrivateData);
+    drop(private_data);
+
+    stream.release = None;
+}
+
+struct StreamPrivateData {
+    batch_reader: Box<dyn RecordBatchReader>,
+    last_error: String,
+}
+
+// The callback used to get array schema
+unsafe extern "C" fn get_schema(
+    stream: *mut FFI_ArrowArrayStream,
+    schema: *mut FFI_ArrowSchema,
+) -> c_int {
+    ExportedArrayStream { stream }.get_schema(schema)
+}
+
+// The callback used to get next array
+unsafe extern "C" fn get_next(
+    stream: *mut FFI_ArrowArrayStream,
+    array: *mut FFI_ArrowArray,
+) -> c_int {
+    ExportedArrayStream { stream }.get_next(array)
+}
+
+// The callback used to get the error from last operation on the `FFI_ArrowArrayStream`
+unsafe extern "C" fn get_last_error(stream: *mut FFI_ArrowArrayStream) -> *const c_char {
+    let last_error = ExportedArrayStream { stream }.get_last_error();
+    CString::new(last_error.as_str()).unwrap().into_raw()
+}
+
+impl Drop for FFI_ArrowArrayStream {
+    fn drop(&mut self) {
+        match self.release {
+            None => (),
+            Some(release) => unsafe { release(self) },
+        };
+    }
+}
+
+impl FFI_ArrowArrayStream {
+    /// create a new [`FFI_ArrowArrayStream`].
+    pub fn new(batch_reader: Box<dyn RecordBatchReader>) -> Self {
+        let private_data = Box::new(StreamPrivateData {
+            batch_reader,
+            last_error: String::new(),
+        });
+
+        Self {
+            get_schema: Some(get_schema),
+            get_next: Some(get_next),
+            get_last_error: Some(get_last_error),
+            release: Some(release_stream),
+            private_data: Box::into_raw(private_data) as *mut c_void,
+        }
+    }
+
+    pub fn empty() -> Self {
+        Self {
+            get_schema: None,
+            get_next: None,
+            get_last_error: None,
+            release: None,
+            private_data: std::ptr::null_mut(),
+        }
+    }
+
+    pub fn to_raw(this: Arc<FFI_ArrowArrayStream>) -> *const FFI_ArrowArrayStream {

Review comment:
       nit: add some comments to this?

##########
File path: arrow/src/ffi_stream.rs
##########
@@ -0,0 +1,515 @@
+// 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.
+
+//! Contains declarations to bind to the [C Stream Interface](https://arrow.apache.org/docs/format/CStreamInterface.html).
+//!
+
+use std::{
+    convert::TryFrom,
+    ffi::CString,
+    os::raw::{c_char, c_int, c_void},
+    sync::Arc,
+};
+
+use crate::array::Array;
+use crate::array::StructArray;
+use crate::datatypes::{Schema, SchemaRef};
+use crate::error::ArrowError;
+use crate::error::Result;
+use crate::ffi::*;
+use crate::record_batch::{RecordBatch, RecordBatchReader};
+
+const ENOMEM: i32 = 12;
+const EIO: i32 = 5;
+const EINVAL: i32 = 22;
+const ENOSYS: i32 = 78;
+
+/// ABI-compatible struct for `ArrayStream` from C Stream Interface
+/// This interface is experimental
+/// See <https://arrow.apache.org/docs/format/CStreamInterface.html#structure-definitions>
+/// This was created by bindgen
+#[repr(C)]
+#[derive(Debug, Clone)]
+pub struct FFI_ArrowArrayStream {
+    pub get_schema: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowSchema,
+        ) -> c_int,
+    >,
+    pub get_next: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowArray,
+        ) -> c_int,
+    >,
+    pub get_last_error:
+        Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream) -> *const c_char>,
+    pub release: Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream)>,
+    pub private_data: *mut c_void,
+}
+
+// callback used to drop [FFI_ArrowArrayStream] when it is exported.
+unsafe extern "C" fn release_stream(stream: *mut FFI_ArrowArrayStream) {
+    if stream.is_null() {
+        return;
+    }
+    let stream = &mut *stream;
+
+    stream.get_schema = None;
+    stream.get_next = None;
+    stream.get_last_error = None;
+
+    let private_data = Box::from_raw(stream.private_data as *mut StreamPrivateData);
+    drop(private_data);
+
+    stream.release = None;
+}
+
+struct StreamPrivateData {
+    batch_reader: Box<dyn RecordBatchReader>,
+    last_error: String,
+}
+
+// The callback used to get array schema
+unsafe extern "C" fn get_schema(
+    stream: *mut FFI_ArrowArrayStream,
+    schema: *mut FFI_ArrowSchema,
+) -> c_int {
+    ExportedArrayStream { stream }.get_schema(schema)
+}
+
+// The callback used to get next array
+unsafe extern "C" fn get_next(
+    stream: *mut FFI_ArrowArrayStream,
+    array: *mut FFI_ArrowArray,
+) -> c_int {
+    ExportedArrayStream { stream }.get_next(array)
+}
+
+// The callback used to get the error from last operation on the `FFI_ArrowArrayStream`
+unsafe extern "C" fn get_last_error(stream: *mut FFI_ArrowArrayStream) -> *const c_char {
+    let last_error = ExportedArrayStream { stream }.get_last_error();
+    CString::new(last_error.as_str()).unwrap().into_raw()
+}
+
+impl Drop for FFI_ArrowArrayStream {
+    fn drop(&mut self) {
+        match self.release {
+            None => (),
+            Some(release) => unsafe { release(self) },
+        };
+    }
+}
+
+impl FFI_ArrowArrayStream {
+    /// create a new [`FFI_ArrowArrayStream`].
+    pub fn new(batch_reader: Box<dyn RecordBatchReader>) -> Self {
+        let private_data = Box::new(StreamPrivateData {
+            batch_reader,
+            last_error: String::new(),
+        });
+
+        Self {
+            get_schema: Some(get_schema),
+            get_next: Some(get_next),
+            get_last_error: Some(get_last_error),
+            release: Some(release_stream),
+            private_data: Box::into_raw(private_data) as *mut c_void,
+        }
+    }
+
+    pub fn empty() -> Self {
+        Self {
+            get_schema: None,
+            get_next: None,
+            get_last_error: None,
+            release: None,
+            private_data: std::ptr::null_mut(),
+        }
+    }
+
+    pub fn to_raw(this: Arc<FFI_ArrowArrayStream>) -> *const FFI_ArrowArrayStream {
+        Arc::into_raw(this)
+    }
+
+    /// Get `FFI_ArrowArrayStream` from raw pointer
+    /// # Safety
+    /// Assumes that the pointer represents valid C Stream Interfaces, both in memory
+    /// representation and lifetime via the `release` mechanism.
+    pub unsafe fn from_raw(
+        ptr: *const FFI_ArrowArrayStream,
+    ) -> Arc<FFI_ArrowArrayStream> {
+        let ffi_stream = (*ptr).clone();
+        Arc::new(ffi_stream)
+    }
+}
+
+struct ExportedArrayStream {
+    stream: *mut FFI_ArrowArrayStream,
+}
+
+impl ExportedArrayStream {
+    fn get_private_data(&self) -> Box<StreamPrivateData> {
+        unsafe { Box::from_raw((*self.stream).private_data as *mut StreamPrivateData) }
+    }
+
+    pub fn get_schema(&self, out: *mut FFI_ArrowSchema) -> i32 {
+        unsafe {
+            match (*out).release {
+                None => (),
+                Some(release) => release(out),
+            };
+        };
+
+        let mut private_data = self.get_private_data();
+        let reader = &private_data.batch_reader;
+
+        let schema = FFI_ArrowSchema::try_from(reader.schema().as_ref());
+
+        let ret_code = match schema {
+            Ok(mut schema) => {
+                unsafe {
+                    (*out).format = schema.format;
+                    (*out).name = schema.name;
+                    (*out).metadata = schema.metadata;
+                    (*out).flags = schema.flags;
+                    (*out).n_children = schema.n_children;
+                    (*out).children = schema.children;
+                    (*out).dictionary = schema.dictionary;
+                    (*out).release = schema.release;
+                    (*out).private_data = schema.private_data;
+                }
+                schema.release = None;
+                0
+            }
+            Err(ref err) => {
+                private_data.last_error = err.to_string();
+                get_error_code(err)
+            }
+        };
+
+        Box::into_raw(private_data);
+        ret_code
+    }
+
+    pub fn get_next(&self, out: *mut FFI_ArrowArray) -> i32 {
+        unsafe {
+            match (*out).release {
+                None => (),
+                Some(release) => release(out),
+            };
+        };
+
+        let mut private_data = self.get_private_data();
+        let reader = &mut private_data.batch_reader;
+
+        let ret_code = match reader.next() {
+            None => 0,
+            Some(next_batch) => {
+                if let Ok(batch) = next_batch {
+                    let struct_array = StructArray::from(batch);
+                    let mut array = FFI_ArrowArray::new(struct_array.data());
+
+                    unsafe {
+                        (*out).length = array.length;
+                        (*out).null_count = array.null_count;
+                        (*out).offset = array.offset;
+                        (*out).n_buffers = array.n_buffers;
+                        (*out).n_children = array.n_children;
+                        (*out).buffers = array.buffers;
+                        (*out).children = array.children;
+                        (*out).dictionary = array.dictionary;
+                        (*out).release = array.release;
+                        (*out).private_data = array.private_data;
+                    }
+
+                    array.release = None;
+                    0
+                } else {
+                    let err = &next_batch.unwrap_err();
+                    private_data.last_error = err.to_string();
+                    get_error_code(err)
+                }
+            }
+        };
+
+        Box::into_raw(private_data);
+        ret_code
+    }
+
+    pub fn get_last_error(&self) -> String {
+        self.get_private_data().last_error
+    }
+}
+
+fn get_error_code(err: &ArrowError) -> i32 {
+    match err {
+        ArrowError::NotYetImplemented(_) => ENOSYS,
+        ArrowError::MemoryError(_) => ENOMEM,
+        ArrowError::IoError(_) => EIO,
+        _ => EINVAL,
+    }
+}
+
+/// A `RecordBatch` reader which imports from `FFI_ArrowArrayStream`
+struct ArrowArrayStreamReader {
+    stream: Arc<FFI_ArrowArrayStream>,
+}
+
+impl ArrowArrayStreamReader {
+    #[allow(dead_code)]
+    pub fn new(stream: FFI_ArrowArrayStream) -> Self {
+        Self {
+            stream: Arc::new(stream),
+        }
+    }
+
+    #[allow(dead_code)]
+    pub fn from_raw(raw_stream: *mut FFI_ArrowArrayStream) -> Self {
+        let stream = unsafe { Arc::new((*raw_stream).clone()) };
+        Self { stream }
+    }
+}
+
+/// Get the last error from `ArrowArrayStreamReader`
+fn get_stream_last_error(stream_reader: &ArrowArrayStreamReader) -> Option<String> {
+    stream_reader.stream.get_last_error?;
+
+    let stream_ptr =
+        Arc::into_raw(stream_reader.stream.clone()) as *mut FFI_ArrowArrayStream;
+
+    let error_str = unsafe {
+        let c_str =
+            stream_reader.stream.get_last_error.unwrap()(stream_ptr) as *mut c_char;
+        CString::from_raw(c_str).into_string()
+    };
+
+    if let Err(err) = error_str {
+        Some(err.to_string())
+    } else {
+        Some(error_str.unwrap())
+    }
+}
+
+impl Iterator for ArrowArrayStreamReader {
+    type Item = Result<RecordBatch>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.stream.get_next?;
+
+        let stream_ptr = Arc::into_raw(self.stream.clone()) as *mut FFI_ArrowArrayStream;
+
+        let empty_array = Arc::new(FFI_ArrowArray::empty());
+        let array_ptr = Arc::into_raw(empty_array) as *mut FFI_ArrowArray;
+
+        let ret_code = unsafe { self.stream.get_next.unwrap()(stream_ptr, array_ptr) };
+
+        let ffi_array = unsafe { Arc::from_raw(array_ptr) };
+
+        // The end of stream has been reached
+        ffi_array.release?;
+
+        let schema_ref = self.schema();
+        let schema = FFI_ArrowSchema::try_from(schema_ref.as_ref());
+
+        if schema.is_err() {
+            return Some(Err(schema.err().unwrap()));
+        }
+
+        if ret_code == 0 {
+            let data = ArrowArray {
+                array: ffi_array,
+                schema: Arc::new(schema.unwrap()),
+            }
+            .to_data();
+
+            if data.is_err() {
+                return Some(Err(data.err().unwrap()));
+            }
+
+            let record_batch = RecordBatch::from(&StructArray::from(data.unwrap()));
+
+            Some(Ok(record_batch))
+        } else {
+            let last_error = get_stream_last_error(self);
+            let err = ArrowError::CDataInterface(last_error.unwrap());
+            Some(Err(err))
+        }
+    }
+}
+
+impl RecordBatchReader for ArrowArrayStreamReader {
+    fn schema(&self) -> SchemaRef {

Review comment:
       I think we can cache the schema locally so we don't have to recreate it every time?

##########
File path: arrow/src/ffi_stream.rs
##########
@@ -0,0 +1,515 @@
+// 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.
+
+//! Contains declarations to bind to the [C Stream Interface](https://arrow.apache.org/docs/format/CStreamInterface.html).
+//!
+
+use std::{
+    convert::TryFrom,
+    ffi::CString,
+    os::raw::{c_char, c_int, c_void},
+    sync::Arc,
+};
+
+use crate::array::Array;
+use crate::array::StructArray;
+use crate::datatypes::{Schema, SchemaRef};
+use crate::error::ArrowError;
+use crate::error::Result;
+use crate::ffi::*;
+use crate::record_batch::{RecordBatch, RecordBatchReader};
+
+const ENOMEM: i32 = 12;
+const EIO: i32 = 5;
+const EINVAL: i32 = 22;
+const ENOSYS: i32 = 78;
+
+/// ABI-compatible struct for `ArrayStream` from C Stream Interface
+/// This interface is experimental
+/// See <https://arrow.apache.org/docs/format/CStreamInterface.html#structure-definitions>
+/// This was created by bindgen
+#[repr(C)]
+#[derive(Debug, Clone)]
+pub struct FFI_ArrowArrayStream {
+    pub get_schema: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowSchema,
+        ) -> c_int,
+    >,
+    pub get_next: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowArray,
+        ) -> c_int,
+    >,
+    pub get_last_error:
+        Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream) -> *const c_char>,
+    pub release: Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream)>,
+    pub private_data: *mut c_void,
+}
+
+// callback used to drop [FFI_ArrowArrayStream] when it is exported.
+unsafe extern "C" fn release_stream(stream: *mut FFI_ArrowArrayStream) {
+    if stream.is_null() {
+        return;
+    }
+    let stream = &mut *stream;
+
+    stream.get_schema = None;
+    stream.get_next = None;
+    stream.get_last_error = None;
+
+    let private_data = Box::from_raw(stream.private_data as *mut StreamPrivateData);
+    drop(private_data);
+
+    stream.release = None;
+}
+
+struct StreamPrivateData {
+    batch_reader: Box<dyn RecordBatchReader>,
+    last_error: String,
+}
+
+// The callback used to get array schema
+unsafe extern "C" fn get_schema(
+    stream: *mut FFI_ArrowArrayStream,
+    schema: *mut FFI_ArrowSchema,
+) -> c_int {
+    ExportedArrayStream { stream }.get_schema(schema)
+}
+
+// The callback used to get next array
+unsafe extern "C" fn get_next(
+    stream: *mut FFI_ArrowArrayStream,
+    array: *mut FFI_ArrowArray,
+) -> c_int {
+    ExportedArrayStream { stream }.get_next(array)
+}
+
+// The callback used to get the error from last operation on the `FFI_ArrowArrayStream`
+unsafe extern "C" fn get_last_error(stream: *mut FFI_ArrowArrayStream) -> *const c_char {
+    let last_error = ExportedArrayStream { stream }.get_last_error();
+    CString::new(last_error.as_str()).unwrap().into_raw()
+}
+
+impl Drop for FFI_ArrowArrayStream {
+    fn drop(&mut self) {
+        match self.release {
+            None => (),
+            Some(release) => unsafe { release(self) },
+        };
+    }
+}
+
+impl FFI_ArrowArrayStream {
+    /// create a new [`FFI_ArrowArrayStream`].
+    pub fn new(batch_reader: Box<dyn RecordBatchReader>) -> Self {
+        let private_data = Box::new(StreamPrivateData {
+            batch_reader,
+            last_error: String::new(),
+        });
+
+        Self {
+            get_schema: Some(get_schema),
+            get_next: Some(get_next),
+            get_last_error: Some(get_last_error),
+            release: Some(release_stream),
+            private_data: Box::into_raw(private_data) as *mut c_void,
+        }
+    }
+
+    pub fn empty() -> Self {
+        Self {
+            get_schema: None,
+            get_next: None,
+            get_last_error: None,
+            release: None,
+            private_data: std::ptr::null_mut(),
+        }
+    }
+
+    pub fn to_raw(this: Arc<FFI_ArrowArrayStream>) -> *const FFI_ArrowArrayStream {
+        Arc::into_raw(this)
+    }
+
+    /// Get `FFI_ArrowArrayStream` from raw pointer
+    /// # Safety
+    /// Assumes that the pointer represents valid C Stream Interfaces, both in memory
+    /// representation and lifetime via the `release` mechanism.
+    pub unsafe fn from_raw(
+        ptr: *const FFI_ArrowArrayStream,
+    ) -> Arc<FFI_ArrowArrayStream> {
+        let ffi_stream = (*ptr).clone();
+        Arc::new(ffi_stream)
+    }
+}
+
+struct ExportedArrayStream {
+    stream: *mut FFI_ArrowArrayStream,
+}
+
+impl ExportedArrayStream {
+    fn get_private_data(&self) -> Box<StreamPrivateData> {
+        unsafe { Box::from_raw((*self.stream).private_data as *mut StreamPrivateData) }
+    }
+
+    pub fn get_schema(&self, out: *mut FFI_ArrowSchema) -> i32 {
+        unsafe {
+            match (*out).release {
+                None => (),
+                Some(release) => release(out),
+            };
+        };
+
+        let mut private_data = self.get_private_data();
+        let reader = &private_data.batch_reader;
+
+        let schema = FFI_ArrowSchema::try_from(reader.schema().as_ref());
+
+        let ret_code = match schema {
+            Ok(mut schema) => {
+                unsafe {
+                    (*out).format = schema.format;
+                    (*out).name = schema.name;
+                    (*out).metadata = schema.metadata;
+                    (*out).flags = schema.flags;
+                    (*out).n_children = schema.n_children;
+                    (*out).children = schema.children;
+                    (*out).dictionary = schema.dictionary;
+                    (*out).release = schema.release;
+                    (*out).private_data = schema.private_data;
+                }
+                schema.release = None;
+                0
+            }
+            Err(ref err) => {
+                private_data.last_error = err.to_string();
+                get_error_code(err)
+            }
+        };
+
+        Box::into_raw(private_data);
+        ret_code
+    }
+
+    pub fn get_next(&self, out: *mut FFI_ArrowArray) -> i32 {
+        unsafe {
+            match (*out).release {
+                None => (),
+                Some(release) => release(out),
+            };
+        };
+
+        let mut private_data = self.get_private_data();
+        let reader = &mut private_data.batch_reader;
+
+        let ret_code = match reader.next() {
+            None => 0,
+            Some(next_batch) => {
+                if let Ok(batch) = next_batch {
+                    let struct_array = StructArray::from(batch);
+                    let mut array = FFI_ArrowArray::new(struct_array.data());
+
+                    unsafe {
+                        (*out).length = array.length;
+                        (*out).null_count = array.null_count;
+                        (*out).offset = array.offset;
+                        (*out).n_buffers = array.n_buffers;
+                        (*out).n_children = array.n_children;
+                        (*out).buffers = array.buffers;
+                        (*out).children = array.children;
+                        (*out).dictionary = array.dictionary;
+                        (*out).release = array.release;
+                        (*out).private_data = array.private_data;
+                    }
+
+                    array.release = None;
+                    0
+                } else {
+                    let err = &next_batch.unwrap_err();
+                    private_data.last_error = err.to_string();
+                    get_error_code(err)
+                }
+            }
+        };
+
+        Box::into_raw(private_data);
+        ret_code
+    }
+
+    pub fn get_last_error(&self) -> String {
+        self.get_private_data().last_error
+    }
+}
+
+fn get_error_code(err: &ArrowError) -> i32 {
+    match err {
+        ArrowError::NotYetImplemented(_) => ENOSYS,
+        ArrowError::MemoryError(_) => ENOMEM,
+        ArrowError::IoError(_) => EIO,
+        _ => EINVAL,
+    }
+}
+
+/// A `RecordBatch` reader which imports from `FFI_ArrowArrayStream`
+struct ArrowArrayStreamReader {

Review comment:
       should this be public?

##########
File path: arrow/src/ffi_stream.rs
##########
@@ -0,0 +1,515 @@
+// 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.
+
+//! Contains declarations to bind to the [C Stream Interface](https://arrow.apache.org/docs/format/CStreamInterface.html).
+//!
+
+use std::{
+    convert::TryFrom,
+    ffi::CString,
+    os::raw::{c_char, c_int, c_void},
+    sync::Arc,
+};
+
+use crate::array::Array;
+use crate::array::StructArray;
+use crate::datatypes::{Schema, SchemaRef};
+use crate::error::ArrowError;
+use crate::error::Result;
+use crate::ffi::*;
+use crate::record_batch::{RecordBatch, RecordBatchReader};
+
+const ENOMEM: i32 = 12;
+const EIO: i32 = 5;
+const EINVAL: i32 = 22;
+const ENOSYS: i32 = 78;
+
+/// ABI-compatible struct for `ArrayStream` from C Stream Interface
+/// This interface is experimental
+/// See <https://arrow.apache.org/docs/format/CStreamInterface.html#structure-definitions>
+/// This was created by bindgen
+#[repr(C)]
+#[derive(Debug, Clone)]
+pub struct FFI_ArrowArrayStream {
+    pub get_schema: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowSchema,
+        ) -> c_int,
+    >,
+    pub get_next: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowArray,
+        ) -> c_int,
+    >,
+    pub get_last_error:
+        Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream) -> *const c_char>,
+    pub release: Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream)>,
+    pub private_data: *mut c_void,
+}
+
+// callback used to drop [FFI_ArrowArrayStream] when it is exported.
+unsafe extern "C" fn release_stream(stream: *mut FFI_ArrowArrayStream) {
+    if stream.is_null() {
+        return;
+    }
+    let stream = &mut *stream;
+
+    stream.get_schema = None;
+    stream.get_next = None;
+    stream.get_last_error = None;
+
+    let private_data = Box::from_raw(stream.private_data as *mut StreamPrivateData);
+    drop(private_data);
+
+    stream.release = None;
+}
+
+struct StreamPrivateData {
+    batch_reader: Box<dyn RecordBatchReader>,
+    last_error: String,
+}
+
+// The callback used to get array schema
+unsafe extern "C" fn get_schema(
+    stream: *mut FFI_ArrowArrayStream,
+    schema: *mut FFI_ArrowSchema,
+) -> c_int {
+    ExportedArrayStream { stream }.get_schema(schema)
+}
+
+// The callback used to get next array
+unsafe extern "C" fn get_next(
+    stream: *mut FFI_ArrowArrayStream,
+    array: *mut FFI_ArrowArray,
+) -> c_int {
+    ExportedArrayStream { stream }.get_next(array)
+}
+
+// The callback used to get the error from last operation on the `FFI_ArrowArrayStream`
+unsafe extern "C" fn get_last_error(stream: *mut FFI_ArrowArrayStream) -> *const c_char {
+    let last_error = ExportedArrayStream { stream }.get_last_error();
+    CString::new(last_error.as_str()).unwrap().into_raw()
+}
+
+impl Drop for FFI_ArrowArrayStream {
+    fn drop(&mut self) {
+        match self.release {
+            None => (),
+            Some(release) => unsafe { release(self) },
+        };
+    }
+}
+
+impl FFI_ArrowArrayStream {
+    /// create a new [`FFI_ArrowArrayStream`].
+    pub fn new(batch_reader: Box<dyn RecordBatchReader>) -> Self {
+        let private_data = Box::new(StreamPrivateData {
+            batch_reader,
+            last_error: String::new(),
+        });
+
+        Self {
+            get_schema: Some(get_schema),
+            get_next: Some(get_next),
+            get_last_error: Some(get_last_error),
+            release: Some(release_stream),
+            private_data: Box::into_raw(private_data) as *mut c_void,
+        }
+    }
+
+    pub fn empty() -> Self {
+        Self {
+            get_schema: None,
+            get_next: None,
+            get_last_error: None,
+            release: None,
+            private_data: std::ptr::null_mut(),
+        }
+    }
+
+    pub fn to_raw(this: Arc<FFI_ArrowArrayStream>) -> *const FFI_ArrowArrayStream {
+        Arc::into_raw(this)
+    }
+
+    /// Get `FFI_ArrowArrayStream` from raw pointer

Review comment:
       nit: maybe we should mention that the input `ptr` is consumed after the call and the ownership of the input `FFI_ArrowArrayStream` has been transferred to the returned value.

##########
File path: arrow/src/ffi_stream.rs
##########
@@ -0,0 +1,515 @@
+// 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.
+
+//! Contains declarations to bind to the [C Stream Interface](https://arrow.apache.org/docs/format/CStreamInterface.html).
+//!
+
+use std::{
+    convert::TryFrom,
+    ffi::CString,
+    os::raw::{c_char, c_int, c_void},
+    sync::Arc,
+};
+
+use crate::array::Array;
+use crate::array::StructArray;
+use crate::datatypes::{Schema, SchemaRef};
+use crate::error::ArrowError;
+use crate::error::Result;
+use crate::ffi::*;
+use crate::record_batch::{RecordBatch, RecordBatchReader};
+
+const ENOMEM: i32 = 12;
+const EIO: i32 = 5;
+const EINVAL: i32 = 22;
+const ENOSYS: i32 = 78;
+
+/// ABI-compatible struct for `ArrayStream` from C Stream Interface
+/// This interface is experimental
+/// See <https://arrow.apache.org/docs/format/CStreamInterface.html#structure-definitions>
+/// This was created by bindgen
+#[repr(C)]
+#[derive(Debug, Clone)]
+pub struct FFI_ArrowArrayStream {
+    pub get_schema: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowSchema,
+        ) -> c_int,
+    >,
+    pub get_next: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowArray,
+        ) -> c_int,
+    >,
+    pub get_last_error:
+        Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream) -> *const c_char>,
+    pub release: Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream)>,
+    pub private_data: *mut c_void,
+}
+
+// callback used to drop [FFI_ArrowArrayStream] when it is exported.
+unsafe extern "C" fn release_stream(stream: *mut FFI_ArrowArrayStream) {
+    if stream.is_null() {
+        return;
+    }
+    let stream = &mut *stream;
+
+    stream.get_schema = None;
+    stream.get_next = None;
+    stream.get_last_error = None;
+
+    let private_data = Box::from_raw(stream.private_data as *mut StreamPrivateData);
+    drop(private_data);
+
+    stream.release = None;
+}
+
+struct StreamPrivateData {
+    batch_reader: Box<dyn RecordBatchReader>,
+    last_error: String,
+}
+
+// The callback used to get array schema
+unsafe extern "C" fn get_schema(
+    stream: *mut FFI_ArrowArrayStream,
+    schema: *mut FFI_ArrowSchema,
+) -> c_int {
+    ExportedArrayStream { stream }.get_schema(schema)
+}
+
+// The callback used to get next array
+unsafe extern "C" fn get_next(
+    stream: *mut FFI_ArrowArrayStream,
+    array: *mut FFI_ArrowArray,
+) -> c_int {
+    ExportedArrayStream { stream }.get_next(array)
+}
+
+// The callback used to get the error from last operation on the `FFI_ArrowArrayStream`
+unsafe extern "C" fn get_last_error(stream: *mut FFI_ArrowArrayStream) -> *const c_char {
+    let last_error = ExportedArrayStream { stream }.get_last_error();
+    CString::new(last_error.as_str()).unwrap().into_raw()
+}
+
+impl Drop for FFI_ArrowArrayStream {
+    fn drop(&mut self) {
+        match self.release {
+            None => (),
+            Some(release) => unsafe { release(self) },
+        };
+    }
+}
+
+impl FFI_ArrowArrayStream {
+    /// create a new [`FFI_ArrowArrayStream`].
+    pub fn new(batch_reader: Box<dyn RecordBatchReader>) -> Self {
+        let private_data = Box::new(StreamPrivateData {
+            batch_reader,
+            last_error: String::new(),
+        });
+
+        Self {
+            get_schema: Some(get_schema),
+            get_next: Some(get_next),
+            get_last_error: Some(get_last_error),
+            release: Some(release_stream),
+            private_data: Box::into_raw(private_data) as *mut c_void,
+        }
+    }
+
+    pub fn empty() -> Self {
+        Self {
+            get_schema: None,
+            get_next: None,
+            get_last_error: None,
+            release: None,
+            private_data: std::ptr::null_mut(),
+        }
+    }
+
+    pub fn to_raw(this: Arc<FFI_ArrowArrayStream>) -> *const FFI_ArrowArrayStream {
+        Arc::into_raw(this)
+    }
+
+    /// Get `FFI_ArrowArrayStream` from raw pointer
+    /// # Safety
+    /// Assumes that the pointer represents valid C Stream Interfaces, both in memory
+    /// representation and lifetime via the `release` mechanism.
+    pub unsafe fn from_raw(
+        ptr: *const FFI_ArrowArrayStream,
+    ) -> Arc<FFI_ArrowArrayStream> {
+        let ffi_stream = (*ptr).clone();
+        Arc::new(ffi_stream)
+    }
+}
+
+struct ExportedArrayStream {
+    stream: *mut FFI_ArrowArrayStream,
+}
+
+impl ExportedArrayStream {
+    fn get_private_data(&self) -> Box<StreamPrivateData> {
+        unsafe { Box::from_raw((*self.stream).private_data as *mut StreamPrivateData) }
+    }
+
+    pub fn get_schema(&self, out: *mut FFI_ArrowSchema) -> i32 {
+        unsafe {
+            match (*out).release {
+                None => (),
+                Some(release) => release(out),
+            };
+        };
+
+        let mut private_data = self.get_private_data();
+        let reader = &private_data.batch_reader;
+
+        let schema = FFI_ArrowSchema::try_from(reader.schema().as_ref());
+
+        let ret_code = match schema {
+            Ok(mut schema) => {
+                unsafe {
+                    (*out).format = schema.format;
+                    (*out).name = schema.name;
+                    (*out).metadata = schema.metadata;
+                    (*out).flags = schema.flags;
+                    (*out).n_children = schema.n_children;
+                    (*out).children = schema.children;
+                    (*out).dictionary = schema.dictionary;
+                    (*out).release = schema.release;
+                    (*out).private_data = schema.private_data;
+                }
+                schema.release = None;
+                0
+            }
+            Err(ref err) => {
+                private_data.last_error = err.to_string();
+                get_error_code(err)
+            }
+        };
+
+        Box::into_raw(private_data);
+        ret_code
+    }
+
+    pub fn get_next(&self, out: *mut FFI_ArrowArray) -> i32 {
+        unsafe {
+            match (*out).release {
+                None => (),
+                Some(release) => release(out),
+            };
+        };
+
+        let mut private_data = self.get_private_data();
+        let reader = &mut private_data.batch_reader;
+
+        let ret_code = match reader.next() {
+            None => 0,
+            Some(next_batch) => {
+                if let Ok(batch) = next_batch {
+                    let struct_array = StructArray::from(batch);
+                    let mut array = FFI_ArrowArray::new(struct_array.data());
+
+                    unsafe {
+                        (*out).length = array.length;
+                        (*out).null_count = array.null_count;
+                        (*out).offset = array.offset;
+                        (*out).n_buffers = array.n_buffers;
+                        (*out).n_children = array.n_children;
+                        (*out).buffers = array.buffers;
+                        (*out).children = array.children;
+                        (*out).dictionary = array.dictionary;
+                        (*out).release = array.release;
+                        (*out).private_data = array.private_data;
+                    }
+
+                    array.release = None;
+                    0
+                } else {
+                    let err = &next_batch.unwrap_err();
+                    private_data.last_error = err.to_string();
+                    get_error_code(err)
+                }
+            }
+        };
+
+        Box::into_raw(private_data);
+        ret_code
+    }
+
+    pub fn get_last_error(&self) -> String {
+        self.get_private_data().last_error
+    }
+}
+
+fn get_error_code(err: &ArrowError) -> i32 {
+    match err {
+        ArrowError::NotYetImplemented(_) => ENOSYS,
+        ArrowError::MemoryError(_) => ENOMEM,
+        ArrowError::IoError(_) => EIO,
+        _ => EINVAL,
+    }
+}
+
+/// A `RecordBatch` reader which imports from `FFI_ArrowArrayStream`
+struct ArrowArrayStreamReader {
+    stream: Arc<FFI_ArrowArrayStream>,
+}
+
+impl ArrowArrayStreamReader {
+    #[allow(dead_code)]
+    pub fn new(stream: FFI_ArrowArrayStream) -> Self {
+        Self {
+            stream: Arc::new(stream),
+        }
+    }
+
+    #[allow(dead_code)]
+    pub fn from_raw(raw_stream: *mut FFI_ArrowArrayStream) -> Self {
+        let stream = unsafe { Arc::new((*raw_stream).clone()) };
+        Self { stream }
+    }
+}
+
+/// Get the last error from `ArrowArrayStreamReader`
+fn get_stream_last_error(stream_reader: &ArrowArrayStreamReader) -> Option<String> {
+    stream_reader.stream.get_last_error?;
+
+    let stream_ptr =
+        Arc::into_raw(stream_reader.stream.clone()) as *mut FFI_ArrowArrayStream;
+
+    let error_str = unsafe {
+        let c_str =
+            stream_reader.stream.get_last_error.unwrap()(stream_ptr) as *mut c_char;
+        CString::from_raw(c_str).into_string()
+    };
+
+    if let Err(err) = error_str {
+        Some(err.to_string())
+    } else {
+        Some(error_str.unwrap())
+    }
+}
+
+impl Iterator for ArrowArrayStreamReader {
+    type Item = Result<RecordBatch>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.stream.get_next?;
+
+        let stream_ptr = Arc::into_raw(self.stream.clone()) as *mut FFI_ArrowArrayStream;
+
+        let empty_array = Arc::new(FFI_ArrowArray::empty());
+        let array_ptr = Arc::into_raw(empty_array) as *mut FFI_ArrowArray;
+
+        let ret_code = unsafe { self.stream.get_next.unwrap()(stream_ptr, array_ptr) };
+
+        let ffi_array = unsafe { Arc::from_raw(array_ptr) };
+
+        // The end of stream has been reached
+        ffi_array.release?;
+
+        let schema_ref = self.schema();
+        let schema = FFI_ArrowSchema::try_from(schema_ref.as_ref());
+
+        if schema.is_err() {
+            return Some(Err(schema.err().unwrap()));
+        }
+
+        if ret_code == 0 {
+            let data = ArrowArray {
+                array: ffi_array,
+                schema: Arc::new(schema.unwrap()),
+            }
+            .to_data();
+
+            if data.is_err() {
+                return Some(Err(data.err().unwrap()));
+            }
+
+            let record_batch = RecordBatch::from(&StructArray::from(data.unwrap()));
+
+            Some(Ok(record_batch))
+        } else {
+            let last_error = get_stream_last_error(self);
+            let err = ArrowError::CDataInterface(last_error.unwrap());
+            Some(Err(err))
+        }
+    }
+}
+
+impl RecordBatchReader for ArrowArrayStreamReader {
+    fn schema(&self) -> SchemaRef {
+        if self.stream.get_schema.is_none() {
+            return Arc::new(Schema::empty());
+        }
+
+        let stream_ptr = Arc::into_raw(self.stream.clone()) as *mut FFI_ArrowArrayStream;
+
+        let empty_schema = Arc::new(FFI_ArrowSchema::empty());
+        let schema_ptr = Arc::into_raw(empty_schema) as *mut FFI_ArrowSchema;
+
+        let ret_code = unsafe { self.stream.get_schema.unwrap()(stream_ptr, schema_ptr) };

Review comment:
       maybe we can have a `try_new` ctor for `ArrowArrayStreamReader` and initialize the cached schema via `get_schema` there.

##########
File path: arrow/src/ffi_stream.rs
##########
@@ -0,0 +1,515 @@
+// 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.
+
+//! Contains declarations to bind to the [C Stream Interface](https://arrow.apache.org/docs/format/CStreamInterface.html).
+//!
+
+use std::{
+    convert::TryFrom,
+    ffi::CString,
+    os::raw::{c_char, c_int, c_void},
+    sync::Arc,
+};
+
+use crate::array::Array;
+use crate::array::StructArray;
+use crate::datatypes::{Schema, SchemaRef};
+use crate::error::ArrowError;
+use crate::error::Result;
+use crate::ffi::*;
+use crate::record_batch::{RecordBatch, RecordBatchReader};
+
+const ENOMEM: i32 = 12;
+const EIO: i32 = 5;
+const EINVAL: i32 = 22;
+const ENOSYS: i32 = 78;
+
+/// ABI-compatible struct for `ArrayStream` from C Stream Interface
+/// This interface is experimental
+/// See <https://arrow.apache.org/docs/format/CStreamInterface.html#structure-definitions>
+/// This was created by bindgen
+#[repr(C)]
+#[derive(Debug, Clone)]
+pub struct FFI_ArrowArrayStream {
+    pub get_schema: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowSchema,
+        ) -> c_int,
+    >,
+    pub get_next: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowArray,
+        ) -> c_int,
+    >,
+    pub get_last_error:
+        Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream) -> *const c_char>,
+    pub release: Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream)>,
+    pub private_data: *mut c_void,
+}
+
+// callback used to drop [FFI_ArrowArrayStream] when it is exported.
+unsafe extern "C" fn release_stream(stream: *mut FFI_ArrowArrayStream) {
+    if stream.is_null() {
+        return;
+    }
+    let stream = &mut *stream;
+
+    stream.get_schema = None;
+    stream.get_next = None;
+    stream.get_last_error = None;
+
+    let private_data = Box::from_raw(stream.private_data as *mut StreamPrivateData);
+    drop(private_data);
+
+    stream.release = None;
+}
+
+struct StreamPrivateData {
+    batch_reader: Box<dyn RecordBatchReader>,
+    last_error: String,
+}
+
+// The callback used to get array schema
+unsafe extern "C" fn get_schema(
+    stream: *mut FFI_ArrowArrayStream,
+    schema: *mut FFI_ArrowSchema,
+) -> c_int {
+    ExportedArrayStream { stream }.get_schema(schema)
+}
+
+// The callback used to get next array
+unsafe extern "C" fn get_next(
+    stream: *mut FFI_ArrowArrayStream,
+    array: *mut FFI_ArrowArray,
+) -> c_int {
+    ExportedArrayStream { stream }.get_next(array)
+}
+
+// The callback used to get the error from last operation on the `FFI_ArrowArrayStream`
+unsafe extern "C" fn get_last_error(stream: *mut FFI_ArrowArrayStream) -> *const c_char {
+    let last_error = ExportedArrayStream { stream }.get_last_error();
+    CString::new(last_error.as_str()).unwrap().into_raw()
+}
+
+impl Drop for FFI_ArrowArrayStream {
+    fn drop(&mut self) {
+        match self.release {
+            None => (),
+            Some(release) => unsafe { release(self) },
+        };
+    }
+}
+
+impl FFI_ArrowArrayStream {
+    /// create a new [`FFI_ArrowArrayStream`].
+    pub fn new(batch_reader: Box<dyn RecordBatchReader>) -> Self {
+        let private_data = Box::new(StreamPrivateData {
+            batch_reader,
+            last_error: String::new(),
+        });
+
+        Self {
+            get_schema: Some(get_schema),
+            get_next: Some(get_next),
+            get_last_error: Some(get_last_error),
+            release: Some(release_stream),
+            private_data: Box::into_raw(private_data) as *mut c_void,
+        }
+    }
+
+    pub fn empty() -> Self {
+        Self {
+            get_schema: None,
+            get_next: None,
+            get_last_error: None,
+            release: None,
+            private_data: std::ptr::null_mut(),
+        }
+    }
+
+    pub fn to_raw(this: Arc<FFI_ArrowArrayStream>) -> *const FFI_ArrowArrayStream {
+        Arc::into_raw(this)
+    }
+
+    /// Get `FFI_ArrowArrayStream` from raw pointer
+    /// # Safety
+    /// Assumes that the pointer represents valid C Stream Interfaces, both in memory
+    /// representation and lifetime via the `release` mechanism.
+    pub unsafe fn from_raw(
+        ptr: *const FFI_ArrowArrayStream,
+    ) -> Arc<FFI_ArrowArrayStream> {
+        let ffi_stream = (*ptr).clone();
+        Arc::new(ffi_stream)
+    }
+}
+
+struct ExportedArrayStream {
+    stream: *mut FFI_ArrowArrayStream,
+}
+
+impl ExportedArrayStream {
+    fn get_private_data(&self) -> Box<StreamPrivateData> {
+        unsafe { Box::from_raw((*self.stream).private_data as *mut StreamPrivateData) }
+    }
+
+    pub fn get_schema(&self, out: *mut FFI_ArrowSchema) -> i32 {
+        unsafe {
+            match (*out).release {
+                None => (),
+                Some(release) => release(out),
+            };
+        };
+
+        let mut private_data = self.get_private_data();
+        let reader = &private_data.batch_reader;
+
+        let schema = FFI_ArrowSchema::try_from(reader.schema().as_ref());
+
+        let ret_code = match schema {
+            Ok(mut schema) => {
+                unsafe {
+                    (*out).format = schema.format;
+                    (*out).name = schema.name;
+                    (*out).metadata = schema.metadata;
+                    (*out).flags = schema.flags;
+                    (*out).n_children = schema.n_children;
+                    (*out).children = schema.children;
+                    (*out).dictionary = schema.dictionary;
+                    (*out).release = schema.release;
+                    (*out).private_data = schema.private_data;
+                }
+                schema.release = None;
+                0
+            }
+            Err(ref err) => {
+                private_data.last_error = err.to_string();
+                get_error_code(err)
+            }
+        };
+
+        Box::into_raw(private_data);
+        ret_code
+    }
+
+    pub fn get_next(&self, out: *mut FFI_ArrowArray) -> i32 {
+        unsafe {
+            match (*out).release {
+                None => (),
+                Some(release) => release(out),
+            };
+        };
+
+        let mut private_data = self.get_private_data();
+        let reader = &mut private_data.batch_reader;
+
+        let ret_code = match reader.next() {
+            None => 0,
+            Some(next_batch) => {
+                if let Ok(batch) = next_batch {
+                    let struct_array = StructArray::from(batch);
+                    let mut array = FFI_ArrowArray::new(struct_array.data());
+
+                    unsafe {
+                        (*out).length = array.length;
+                        (*out).null_count = array.null_count;
+                        (*out).offset = array.offset;
+                        (*out).n_buffers = array.n_buffers;
+                        (*out).n_children = array.n_children;
+                        (*out).buffers = array.buffers;
+                        (*out).children = array.children;
+                        (*out).dictionary = array.dictionary;
+                        (*out).release = array.release;
+                        (*out).private_data = array.private_data;
+                    }
+
+                    array.release = None;
+                    0
+                } else {
+                    let err = &next_batch.unwrap_err();
+                    private_data.last_error = err.to_string();
+                    get_error_code(err)
+                }
+            }
+        };
+
+        Box::into_raw(private_data);
+        ret_code
+    }
+
+    pub fn get_last_error(&self) -> String {
+        self.get_private_data().last_error
+    }
+}
+
+fn get_error_code(err: &ArrowError) -> i32 {
+    match err {
+        ArrowError::NotYetImplemented(_) => ENOSYS,
+        ArrowError::MemoryError(_) => ENOMEM,
+        ArrowError::IoError(_) => EIO,
+        _ => EINVAL,
+    }
+}
+
+/// A `RecordBatch` reader which imports from `FFI_ArrowArrayStream`
+struct ArrowArrayStreamReader {
+    stream: Arc<FFI_ArrowArrayStream>,
+}
+
+impl ArrowArrayStreamReader {
+    #[allow(dead_code)]
+    pub fn new(stream: FFI_ArrowArrayStream) -> Self {
+        Self {
+            stream: Arc::new(stream),
+        }
+    }
+
+    #[allow(dead_code)]
+    pub fn from_raw(raw_stream: *mut FFI_ArrowArrayStream) -> Self {
+        let stream = unsafe { Arc::new((*raw_stream).clone()) };
+        Self { stream }
+    }
+}
+
+/// Get the last error from `ArrowArrayStreamReader`
+fn get_stream_last_error(stream_reader: &ArrowArrayStreamReader) -> Option<String> {
+    stream_reader.stream.get_last_error?;
+
+    let stream_ptr =
+        Arc::into_raw(stream_reader.stream.clone()) as *mut FFI_ArrowArrayStream;
+
+    let error_str = unsafe {
+        let c_str =
+            stream_reader.stream.get_last_error.unwrap()(stream_ptr) as *mut c_char;
+        CString::from_raw(c_str).into_string()
+    };
+
+    if let Err(err) = error_str {
+        Some(err.to_string())
+    } else {
+        Some(error_str.unwrap())
+    }
+}
+
+impl Iterator for ArrowArrayStreamReader {
+    type Item = Result<RecordBatch>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.stream.get_next?;
+
+        let stream_ptr = Arc::into_raw(self.stream.clone()) as *mut FFI_ArrowArrayStream;
+
+        let empty_array = Arc::new(FFI_ArrowArray::empty());
+        let array_ptr = Arc::into_raw(empty_array) as *mut FFI_ArrowArray;
+
+        let ret_code = unsafe { self.stream.get_next.unwrap()(stream_ptr, array_ptr) };
+
+        let ffi_array = unsafe { Arc::from_raw(array_ptr) };
+
+        // The end of stream has been reached
+        ffi_array.release?;
+
+        let schema_ref = self.schema();
+        let schema = FFI_ArrowSchema::try_from(schema_ref.as_ref());
+
+        if schema.is_err() {
+            return Some(Err(schema.err().unwrap()));
+        }
+
+        if ret_code == 0 {
+            let data = ArrowArray {
+                array: ffi_array,
+                schema: Arc::new(schema.unwrap()),
+            }
+            .to_data();
+
+            if data.is_err() {
+                return Some(Err(data.err().unwrap()));
+            }
+
+            let record_batch = RecordBatch::from(&StructArray::from(data.unwrap()));
+
+            Some(Ok(record_batch))
+        } else {
+            let last_error = get_stream_last_error(self);
+            let err = ArrowError::CDataInterface(last_error.unwrap());
+            Some(Err(err))
+        }
+    }
+}
+
+impl RecordBatchReader for ArrowArrayStreamReader {
+    fn schema(&self) -> SchemaRef {
+        if self.stream.get_schema.is_none() {

Review comment:
       I think we can just unwrap here instead of returning an empty schema. It's an implementation error if the callback is not set.

##########
File path: arrow/src/ffi_stream.rs
##########
@@ -0,0 +1,515 @@
+// 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.
+
+//! Contains declarations to bind to the [C Stream Interface](https://arrow.apache.org/docs/format/CStreamInterface.html).
+//!
+
+use std::{
+    convert::TryFrom,
+    ffi::CString,
+    os::raw::{c_char, c_int, c_void},
+    sync::Arc,
+};
+
+use crate::array::Array;
+use crate::array::StructArray;
+use crate::datatypes::{Schema, SchemaRef};
+use crate::error::ArrowError;
+use crate::error::Result;
+use crate::ffi::*;
+use crate::record_batch::{RecordBatch, RecordBatchReader};
+
+const ENOMEM: i32 = 12;
+const EIO: i32 = 5;
+const EINVAL: i32 = 22;
+const ENOSYS: i32 = 78;
+
+/// ABI-compatible struct for `ArrayStream` from C Stream Interface
+/// This interface is experimental
+/// See <https://arrow.apache.org/docs/format/CStreamInterface.html#structure-definitions>
+/// This was created by bindgen
+#[repr(C)]
+#[derive(Debug, Clone)]
+pub struct FFI_ArrowArrayStream {
+    pub get_schema: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowSchema,
+        ) -> c_int,
+    >,
+    pub get_next: Option<
+        unsafe extern "C" fn(
+            arg1: *mut FFI_ArrowArrayStream,
+            out: *mut FFI_ArrowArray,
+        ) -> c_int,
+    >,
+    pub get_last_error:
+        Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream) -> *const c_char>,
+    pub release: Option<unsafe extern "C" fn(arg1: *mut FFI_ArrowArrayStream)>,
+    pub private_data: *mut c_void,
+}
+
+// callback used to drop [FFI_ArrowArrayStream] when it is exported.
+unsafe extern "C" fn release_stream(stream: *mut FFI_ArrowArrayStream) {
+    if stream.is_null() {
+        return;
+    }
+    let stream = &mut *stream;
+
+    stream.get_schema = None;
+    stream.get_next = None;
+    stream.get_last_error = None;
+
+    let private_data = Box::from_raw(stream.private_data as *mut StreamPrivateData);
+    drop(private_data);
+
+    stream.release = None;
+}
+
+struct StreamPrivateData {
+    batch_reader: Box<dyn RecordBatchReader>,
+    last_error: String,
+}
+
+// The callback used to get array schema
+unsafe extern "C" fn get_schema(
+    stream: *mut FFI_ArrowArrayStream,
+    schema: *mut FFI_ArrowSchema,
+) -> c_int {
+    ExportedArrayStream { stream }.get_schema(schema)
+}
+
+// The callback used to get next array
+unsafe extern "C" fn get_next(
+    stream: *mut FFI_ArrowArrayStream,
+    array: *mut FFI_ArrowArray,
+) -> c_int {
+    ExportedArrayStream { stream }.get_next(array)
+}
+
+// The callback used to get the error from last operation on the `FFI_ArrowArrayStream`
+unsafe extern "C" fn get_last_error(stream: *mut FFI_ArrowArrayStream) -> *const c_char {
+    let last_error = ExportedArrayStream { stream }.get_last_error();
+    CString::new(last_error.as_str()).unwrap().into_raw()
+}
+
+impl Drop for FFI_ArrowArrayStream {
+    fn drop(&mut self) {
+        match self.release {
+            None => (),
+            Some(release) => unsafe { release(self) },
+        };
+    }
+}
+
+impl FFI_ArrowArrayStream {
+    /// create a new [`FFI_ArrowArrayStream`].
+    pub fn new(batch_reader: Box<dyn RecordBatchReader>) -> Self {
+        let private_data = Box::new(StreamPrivateData {
+            batch_reader,
+            last_error: String::new(),
+        });
+
+        Self {
+            get_schema: Some(get_schema),
+            get_next: Some(get_next),
+            get_last_error: Some(get_last_error),
+            release: Some(release_stream),
+            private_data: Box::into_raw(private_data) as *mut c_void,
+        }
+    }
+
+    pub fn empty() -> Self {
+        Self {
+            get_schema: None,
+            get_next: None,
+            get_last_error: None,
+            release: None,
+            private_data: std::ptr::null_mut(),
+        }
+    }
+
+    pub fn to_raw(this: Arc<FFI_ArrowArrayStream>) -> *const FFI_ArrowArrayStream {
+        Arc::into_raw(this)
+    }
+
+    /// Get `FFI_ArrowArrayStream` from raw pointer
+    /// # Safety
+    /// Assumes that the pointer represents valid C Stream Interfaces, both in memory
+    /// representation and lifetime via the `release` mechanism.
+    pub unsafe fn from_raw(
+        ptr: *const FFI_ArrowArrayStream,
+    ) -> Arc<FFI_ArrowArrayStream> {
+        let ffi_stream = (*ptr).clone();
+        Arc::new(ffi_stream)
+    }
+}
+
+struct ExportedArrayStream {
+    stream: *mut FFI_ArrowArrayStream,
+}
+
+impl ExportedArrayStream {
+    fn get_private_data(&self) -> Box<StreamPrivateData> {

Review comment:
       nit: can we just return `&mut StreamPrivateData`




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