Reorganize ORC reader into multiple files and perform some small fixes to cuIO code

cpp/CMakeLists.txt

@@ -380,6 +380,8 @@ add_library(
   src/io/orc/dict_enc.cu
   src/io/orc/orc.cpp
   src/io/orc/reader_impl.cu
+  src/io/orc/reader_impl_helpers.cpp
+  src/io/orc/reader_impl_preprocess.cu
   src/io/orc/stats_enc.cu
   src/io/orc/stripe_data.cu
   src/io/orc/stripe_enc.cu

cpp/src/io/orc/aggregate_orc_metadata.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2023, NVIDIA CORPORATION.
+ * Copyright (c) 2021-2024, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,7 +20,6 @@
 
 #include <algorithm>
 #include <numeric>
-#include <optional>
 
 namespace cudf::io::orc::detail {
 
@@ -220,27 +219,25 @@ aggregate_orc_metadata::select_stripes(
   }
 
   // Read each stripe's stripefooter metadata
-  if (not selected_stripes_mapping.empty()) {
-    for (auto& mapping : selected_stripes_mapping) {
-      // Resize to all stripe_info for the source level
-      per_file_metadata[mapping.source_idx].stripefooters.resize(mapping.stripe_info.size());
-
-      for (size_t i = 0; i < mapping.stripe_info.size(); i++) {
-        auto const stripe         = mapping.stripe_info[i].first;
-        auto const sf_comp_offset = stripe->offset + stripe->indexLength + stripe->dataLength;
-        auto const sf_comp_length = stripe->footerLength;
-        CUDF_EXPECTS(
-          sf_comp_offset + sf_comp_length < per_file_metadata[mapping.source_idx].source->size(),
-          "Invalid stripe information");
-        auto const buffer =
-          per_file_metadata[mapping.source_idx].source->host_read(sf_comp_offset, sf_comp_length);
-        auto sf_data = per_file_metadata[mapping.source_idx].decompressor->decompress_blocks(
-          {buffer->data(), buffer->size()}, stream);
-        ProtobufReader(sf_data.data(), sf_data.size())
-          .read(per_file_metadata[mapping.source_idx].stripefooters[i]);
-        mapping.stripe_info[i].second = &per_file_metadata[mapping.source_idx].stripefooters[i];
-        if (stripe->indexLength == 0) { row_grp_idx_present = false; }
-      }
+  for (auto& mapping : selected_stripes_mapping) {
+    // Resize to all stripe_info for the source level
+    per_file_metadata[mapping.source_idx].stripefooters.resize(mapping.stripe_info.size());
+
+    for (size_t i = 0; i < mapping.stripe_info.size(); i++) {
+      auto const stripe         = mapping.stripe_info[i].first;
+      auto const sf_comp_offset = stripe->offset + stripe->indexLength + stripe->dataLength;
+      auto const sf_comp_length = stripe->footerLength;
+      CUDF_EXPECTS(
+        sf_comp_offset + sf_comp_length < per_file_metadata[mapping.source_idx].source->size(),
+        "Invalid stripe information");
+      auto const buffer =
+        per_file_metadata[mapping.source_idx].source->host_read(sf_comp_offset, sf_comp_length);
+      auto sf_data = per_file_metadata[mapping.source_idx].decompressor->decompress_blocks(
+        {buffer->data(), buffer->size()}, stream);
+      ProtobufReader(sf_data.data(), sf_data.size())
+        .read(per_file_metadata[mapping.source_idx].stripefooters[i]);
+      mapping.stripe_info[i].second = &per_file_metadata[mapping.source_idx].stripefooters[i];
+      if (stripe->indexLength == 0) { row_grp_idx_present = false; }
     }
   }
 
@@ -270,7 +267,7 @@ column_hierarchy aggregate_orc_metadata::select_columns(
       CUDF_EXPECTS(name_found, "Unknown column name: " + std::string(path));
     }
   }
-  return {std::move(selected_columns)};
+  return column_hierarchy{std::move(selected_columns)};
 }
 
 }  // namespace cudf::io::orc::detail

cpp/src/io/orc/aggregate_orc_metadata.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2023, NVIDIA CORPORATION.
+ * Copyright (c) 2021-2024, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+#pragma once
+
 #include "orc.hpp"
 
 #include <map>
@@ -33,8 +35,8 @@ struct column_hierarchy {
   // Each element contains column at the given nesting level
   std::vector<std::vector<orc_column_meta>> levels;
 
-  column_hierarchy(nesting_map child_map);
-  auto num_levels() const { return levels.size(); }
+  explicit column_hierarchy(nesting_map child_map);
+  [[nodiscard]] auto num_levels() const { return levels.size(); }
 };
 
 /**
@@ -50,11 +52,6 @@ class aggregate_orc_metadata {
    */
   [[nodiscard]] int64_t calc_num_rows() const;
 
-  /**
-   * @brief Number of columns in a ORC file.
-   */
-  [[nodiscard]] size_type calc_num_cols() const;
-
   /**
    * @brief Sums up the number of stripes of each source
    */
@@ -69,22 +66,23 @@ class aggregate_orc_metadata {
   aggregate_orc_metadata(std::vector<std::unique_ptr<datasource>> const& sources,
                          rmm::cuda_stream_view stream);
 
-  [[nodiscard]] auto const& get_schema(int schema_idx) const
+  [[nodiscard]] auto get_col_type(int col_idx) const
   {
-    return per_file_metadata[0].ff.types[schema_idx];
+    return per_file_metadata[0].ff.types[col_idx];
   }
 
-  auto get_col_type(int col_idx) const { return per_file_metadata[0].ff.types[col_idx]; }
-
   [[nodiscard]] auto get_num_rows() const { return num_rows; }
 
-  auto get_num_cols() const { return per_file_metadata[0].get_num_columns(); }
+  [[nodiscard]] auto get_num_cols() const { return per_file_metadata[0].get_num_columns(); }
 
   [[nodiscard]] auto get_num_stripes() const { return num_stripes; }
 
   [[nodiscard]] auto const& get_types() const { return per_file_metadata[0].ff.types; }
 
-  [[nodiscard]] int get_row_index_stride() const { return per_file_metadata[0].ff.rowIndexStride; }
+  [[nodiscard]] int get_row_index_stride() const
+  {
+    return static_cast<int>(per_file_metadata[0].ff.rowIndexStride);
+  }
 
   [[nodiscard]] auto is_row_grp_idx_present() const { return row_grp_idx_present; }
 
@@ -115,11 +113,11 @@ class aggregate_orc_metadata {
    *
    * Stripes are potentially selected from multiple files.
    */
-  std::tuple<int64_t, size_type, std::vector<metadata::stripe_source_mapping>> select_stripes(
-    std::vector<std::vector<size_type>> const& user_specified_stripes,
-    uint64_t skip_rows,
-    std::optional<size_type> const& num_rows,
-    rmm::cuda_stream_view stream);
+  [[nodiscard]] std::tuple<int64_t, size_type, std::vector<metadata::stripe_source_mapping>>
+  select_stripes(std::vector<std::vector<size_type>> const& user_specified_stripes,
+                 uint64_t skip_rows,
+                 std::optional<size_type> const& num_rows,
+                 rmm::cuda_stream_view stream);
 
   /**
    * @brief Filters ORC file to a selection of columns, based on their paths in the file.
@@ -131,7 +129,7 @@ class aggregate_orc_metadata {
    * `nullopt` if user did not select columns to read
    * @return Columns hierarchy - lists of children columns and sorted columns in each nesting level
    */
-  column_hierarchy select_columns(
+  [[nodiscard]] column_hierarchy select_columns(
     std::optional<std::vector<std::string>> const& column_paths) const;
 };