Expose stream-ordering in scalar and avro APIs (#17766)

Contributes to #13744

Replaces conversion operators in derived classes of `cudf::scalar` with stream-ordered `get_value(stream)` member function.
Adds stream parameter to `cudf::io::read_avro`

Authors:
  - Shruti Shivakumar (https://github.com/shrshi)
  - Vyas Ramasubramani (https://github.com/vyasr)

Approvers:
  - Bradley Dice (https://github.com/bdice)
  - Vukasin Milovanovic (https://github.com/vuule)
  - David Wendt (https://github.com/davidwendt)
  - https://github.com/nvdbaranec

URL: #17766

cpp/include/cudf/io/avro.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2024, NVIDIA CORPORATION.
+ * Copyright (c) 2020-2025, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -208,13 +208,15 @@ class avro_reader_options_builder {
  * @endcode
  *
  * @param options Settings for controlling reading behavior
+ * @param stream CUDA stream used for device memory operations and kernel launches
  * @param mr Device memory resource used to allocate device memory of the table in the returned
  * table_with_metadata
  *
  * @return The set of columns along with metadata
  */
 table_with_metadata read_avro(
   avro_reader_options const& options,
+  rmm::cuda_stream_view stream      = cudf::get_default_stream(),
   rmm::device_async_resource_ref mr = cudf::get_current_device_resource_ref());
 
 /** @} */  // end of group

cpp/include/cudf/scalar/scalar.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019-2024, NVIDIA CORPORATION.
+ * Copyright (c) 2019-2025, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -176,11 +176,6 @@ class fixed_width_scalar : public scalar {
    */
   void set_value(T value, rmm::cuda_stream_view stream = cudf::get_default_stream());
 
-  /**
-   * @brief Explicit conversion operator to get the value of the scalar on the host.
-   */
-  explicit operator value_type() const;
-
   /**
    * @brief Get the value of the scalar.
    *
@@ -402,11 +397,6 @@ class fixed_point_scalar : public scalar {
   [[nodiscard]] T fixed_point_value(
     rmm::cuda_stream_view stream = cudf::get_default_stream()) const;
 
-  /**
-   * @brief Explicit conversion operator to get the value of the scalar on the host.
-   */
-  explicit operator value_type() const;
-
   /**
    * @brief Returns a raw pointer to the value in device memory.
    * @return A raw pointer to the value in device memory
@@ -515,11 +505,6 @@ class string_scalar : public scalar {
                 rmm::cuda_stream_view stream      = cudf::get_default_stream(),
                 rmm::device_async_resource_ref mr = cudf::get_current_device_resource_ref());
 
-  /**
-   * @brief Explicit conversion operator to get the value of the scalar in a host std::string.
-   */
-  explicit operator std::string() const;
-
   /**
    * @brief Get the value of the scalar in a host std::string.
    *

cpp/src/io/functions.cpp

@@ -189,7 +189,9 @@ std::vector<std::unique_ptr<data_sink>> make_datasinks(sink_info const& info)
 
 }  // namespace
 
-table_with_metadata read_avro(avro_reader_options const& options, rmm::device_async_resource_ref mr)
+table_with_metadata read_avro(avro_reader_options const& options,
+                              rmm::cuda_stream_view stream,
+                              rmm::device_async_resource_ref mr)
 {
   namespace avro = cudf::io::detail::avro;
 
@@ -199,7 +201,7 @@ table_with_metadata read_avro(avro_reader_options const& options, rmm::device_as
 
   CUDF_EXPECTS(datasources.size() == 1, "Only a single source is currently supported.");
 
-  return avro::read_avro(std::move(datasources[0]), options, cudf::get_default_stream(), mr);
+  return avro::read_avro(std::move(datasources[0]), options, stream, mr);
 }
 
 table_with_metadata read_json(json_reader_options options,

cpp/src/scalar/scalar.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019-2024, NVIDIA CORPORATION.
+ * Copyright (c) 2019-2025, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -110,8 +110,6 @@ size_type string_scalar::size() const { return _data.size(); }
 
 char const* string_scalar::data() const { return static_cast<char const*>(_data.data()); }
 
-string_scalar::operator std::string() const { return this->to_string(cudf::get_default_stream()); }
-
 std::string string_scalar::to_string(rmm::cuda_stream_view stream) const
 {
   std::string result(size(), '\0');
@@ -183,12 +181,6 @@ T fixed_point_scalar<T>::fixed_point_value(rmm::cuda_stream_view stream) const
     numeric::scaled_integer<rep_type>{_data.value(stream), numeric::scale_type{type().scale()}}};
 }
 
-template <typename T>
-fixed_point_scalar<T>::operator value_type() const
-{
-  return this->fixed_point_value(cudf::get_default_stream());
-}
-
 template <typename T>
 typename fixed_point_scalar<T>::rep_type* fixed_point_scalar<T>::data()
 {
@@ -266,12 +258,6 @@ T const* fixed_width_scalar<T>::data() const
   return _data.data();
 }
 
-template <typename T>
-fixed_width_scalar<T>::operator value_type() const
-{
-  return this->value(cudf::get_default_stream());
-}
-
 /**
  * @brief These define the valid fixed-width scalar types.
  *

cpp/tests/CMakeLists.txt

@@ -725,6 +725,7 @@ ConfigureTest(STREAM_REPLACE_TEST streams/replace_test.cpp STREAM_MODE testing)
 ConfigureTest(STREAM_RESHAPE_TEST streams/reshape_test.cpp STREAM_MODE testing)
 ConfigureTest(STREAM_ROLLING_TEST streams/rolling_test.cpp STREAM_MODE testing)
 ConfigureTest(STREAM_ROUND_TEST streams/round_test.cpp STREAM_MODE testing)
+ConfigureTest(STREAM_SCALAR_TEST streams/scalar_test.cpp STREAM_MODE testing)
 ConfigureTest(STREAM_SEARCH_TEST streams/search_test.cpp STREAM_MODE testing)
 ConfigureTest(STREAM_SORTING_TEST streams/sorting_test.cpp STREAM_MODE testing)
 ConfigureTest(STREAM_STREAM_COMPACTION_TEST streams/stream_compaction_test.cpp STREAM_MODE testing)

cpp/tests/binaryop/assert-binops.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019-2023, NVIDIA CORPORATION.
+ * Copyright (c) 2019-2025, NVIDIA CORPORATION.
  *
  * Copyright 2018-2019 BlazingDB, Inc.
  *     Copyright 2018 Christian Noboa Mardini <[email protected]>
@@ -69,6 +69,20 @@ struct NearEqualComparator {
   }
 };
 
+template <typename TypeLhs, typename ScalarType>
+TypeLhs scalar_host_value(cudf::scalar const& lhs)
+{
+  auto sclr   = static_cast<ScalarType const&>(lhs);
+  auto stream = cudf::get_default_stream();
+  if constexpr (std::is_same_v<ScalarType, cudf::string_scalar>) {
+    return sclr.to_string(stream);
+  } else if constexpr (std::is_same_v<ScalarType, cudf::fixed_point_scalar<TypeLhs>>) {
+    return sclr.fixed_point_value(stream);
+  } else {
+    return sclr.value(stream);
+  }
+}
+
 template <typename TypeOut,
           typename TypeLhs,
           typename TypeRhs,
@@ -81,7 +95,7 @@ void ASSERT_BINOP(cudf::column_view const& out,
                   TypeOp&& op,
                   ValueComparator const& value_comparator = ValueComparator())
 {
-  auto lhs_h    = static_cast<ScalarType const&>(lhs).operator TypeLhs();
+  auto lhs_h    = scalar_host_value<TypeLhs, ScalarType>(lhs);
   auto rhs_h    = cudf::test::to_host<TypeRhs>(rhs);
   auto rhs_data = rhs_h.first;
   auto out_h    = cudf::test::to_host<TypeOut>(out);
@@ -129,7 +143,7 @@ void ASSERT_BINOP(cudf::column_view const& out,
                   TypeOp&& op,
                   ValueComparator const& value_comparator = ValueComparator())
 {
-  auto rhs_h    = static_cast<ScalarType const&>(rhs).operator TypeRhs();
+  auto rhs_h    = scalar_host_value<TypeRhs, ScalarType>(rhs);
   auto lhs_h    = cudf::test::to_host<TypeLhs>(lhs);
   auto lhs_data = lhs_h.first;
   auto out_h    = cudf::test::to_host<TypeOut>(out);

cpp/tests/streams/scalar_test.cpp

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2025, NVIDIA CORPORATION.
+ *
+ * Licensed 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.
+ */
+
+#include <cudf_test/base_fixture.hpp>
+#include <cudf_test/default_stream.hpp>
+#include <cudf_test/type_lists.hpp>
+
+#include <cudf/scalar/scalar.hpp>
+
+template <typename T>
+struct TypedScalarTest : public cudf::test::BaseFixture {};
+
+TYPED_TEST_SUITE(TypedScalarTest, cudf::test::FixedWidthTypes);
+
+TYPED_TEST(TypedScalarTest, DefaultValidity)
+{
+  using Type = cudf::device_storage_type_t<TypeParam>;
+  Type value = static_cast<Type>(cudf::test::make_type_param_scalar<TypeParam>(7));
+  cudf::scalar_type_t<TypeParam> s(value, true, cudf::test::get_default_stream());
+  EXPECT_EQ(value, s.value(cudf::test::get_default_stream()));
+}
+
+struct StringScalarTest : public cudf::test::BaseFixture {};
+
+TEST_F(StringScalarTest, DefaultValidity)
+{
+  std::string value = "test string";
+  auto s            = cudf::string_scalar(value, true, cudf::test::get_default_stream());
+  EXPECT_EQ(value, s.to_string(cudf::test::get_default_stream()));
+}