Aduffy/more device arrays (#6308)

Signed-off-by: Andrew Duffy <andrew@a10y.dev>

Author: a10y

vortex-cuda/cudf-test/src/lib.rs

@@ -2,6 +2,14 @@
 // SPDX-FileCopyrightText: Copyright the Vortex contributors
 
 //! This file is a simple C-compatible API that is called from the cudf-test-harness at CI time.
+//!
+//! The flow is
+//!
+//!     * test harness calls `dlopen` in this library
+//!     * invokes the `export_array` function to get back the device array
+//!     * pass the arrays to `cudf`'s `from_arrow_device_column`
+//!     * run some operations on the loaded column view
+//!     * call `array->release()` to drop the data allocated from the Rust side
 
 #![allow(clippy::unwrap_used, clippy::expect_used)]
 
@@ -11,10 +19,13 @@ use arrow_schema::ffi::FFI_ArrowSchema;
 use futures::executor::block_on;
 use vortex::array::Array;
 use vortex::array::IntoArray;
+use vortex::array::arrays::DecimalArray;
 use vortex::array::arrays::PrimitiveArray;
 use vortex::array::arrays::StructArray;
+use vortex::array::arrays::VarBinViewArray;
 use vortex::array::session::ArraySession;
 use vortex::array::validity::Validity;
+use vortex::dtype::DecimalDType;
 use vortex::dtype::FieldNames;
 use vortex::expr::session::ExprSession;
 use vortex::io::session::RuntimeSession;
@@ -35,7 +46,6 @@ static SESSION: LazyLock<VortexSession> = LazyLock::new(|| {
         .with::<CudaSession>()
 });
 
-/// External array
 #[unsafe(no_mangle)]
 pub extern "C" fn export_array(
     schema_ptr: &mut FFI_ArrowSchema,
@@ -44,10 +54,17 @@ pub extern "C" fn export_array(
     let mut ctx = CudaSession::create_execution_ctx(&SESSION).unwrap();
 
     let primitive = PrimitiveArray::from_iter(0u32..1024);
+    let string =
+        VarBinViewArray::from_iter_str((0..1024).map(|idx| format!("this is string {idx}")));
+    let decimal = DecimalArray::from_iter(0i64..1024, DecimalDType::new(19, 2));
 
     let array = StructArray::new(
-        FieldNames::from_iter(["a"]),
-        vec![primitive.into_array()],
+        FieldNames::from_iter(["prims", "strings", "decimals"]),
+        vec![
+            primitive.into_array(),
+            string.into_array(),
+            decimal.into_array(),
+        ],
         1024,
         Validity::NonNullable,
     )