Add a new nullable function for table_views and address various minor…

… outstanding PR comments from PR rapidsai#8214.

cpp/include/cudf/ast/detail/linearizer.hpp

@@ -108,7 +108,7 @@ class linearizer {
    * @param right The right table used for evaluating the abstract syntax tree.
    */
   linearizer(detail::node const& expr, cudf::table_view left, cudf::table_view right)
-    : _left(left), _right(right), _node_count(0), _intermediate_counter()
+    : _left{left}, _right{right}, _node_count{0}, _intermediate_counter{}
   {
     expr.accept(*this);
   }
@@ -120,7 +120,7 @@ class linearizer {
    * @param table The table used for evaluating the abstract syntax tree.
    */
   linearizer(detail::node const& expr, cudf::table_view table)
-    : _left(table), _right(table), _node_count(0), _intermediate_counter()
+    : _left{table}, _right{table}, _node_count{0}, _intermediate_counter{}
   {
     expr.accept(*this);
   }

cpp/include/cudf/join.hpp

@@ -658,6 +658,9 @@ class hash_join {
  * The corresponding values in the second returned vector are
  * the matched row indices from the right table.
  *
+ * If the provided predicate returns NULL for a pair of pair of rows
+ * (left, right), that pair is not included in the output.
+ *
  * @code{.pseudo}
  * Left: {{0, 1, 2}}
  * Right: {{1, 2, 3}}
@@ -672,6 +675,7 @@ class hash_join {
  *
  * @throw cudf::logic_error if number of elements in `left_keys` or `right_keys`
  * mismatch.
+ * @throw cudf::logic_error if the binary predicate outputs a non-boolean result.
  *
  * @param left The left table
  * @param right The right table
@@ -702,6 +706,9 @@ conditional_inner_join(
  * from the right table, if there is a match  or  (2) an unspecified
  * out-of-bounds value.
  *
+ * If the provided predicate returns NULL for a pair of pair of rows
+ * (left, right), that pair is not included in the output.
+ *
  * @code{.pseudo}
  * Left: {{0, 1, 2}}
  * Right: {{1, 2, 3}}
@@ -716,6 +723,7 @@ conditional_inner_join(
  *
  * @throw cudf::logic_error if number of elements in `left_keys` or `right_keys`
  * mismatch.
+ * @throw cudf::logic_error if the binary predicate outputs a non-boolean result.
  *
  * @param left The left table
  * @param right The right table
@@ -744,6 +752,9 @@ conditional_left_join(table_view left,
  * right tables, (2) a row index and an unspecified out-of-bounds value,
  * representing a row from one table without a match in the other.
  *
+ * If the provided predicate returns NULL for a pair of pair of rows
+ * (left, right), that pair is not included in the output.
+ *
  * @code{.pseudo}
  * Left: {{0, 1, 2}}
  * Right: {{1, 2, 3}}
@@ -758,6 +769,7 @@ conditional_left_join(table_view left,
  *
  * @throw cudf::logic_error if number of elements in `left_keys` or `right_keys`
  * mismatch.
+ * @throw cudf::logic_error if the binary predicate outputs a non-boolean result.
  *
  * @param left The left table
  * @param right The right table
@@ -781,6 +793,9 @@ conditional_full_join(table_view left,
  * for which there exists some row in the right table where the predicate
  * evaluates to true.
  *
+ * If the provided predicate returns NULL for a pair of pair of rows
+ * (left, right), that pair is not included in the output.
+ *
  * @code{.pseudo}
  * Left: {{0, 1, 2}}
  * Right: {{1, 2, 3}}
@@ -795,6 +810,7 @@ conditional_full_join(table_view left,
  *
  * @throw cudf::logic_error if number of elements in `left_keys` or `right_keys`
  * mismatch.
+ * @throw cudf::logic_error if the binary predicate outputs a non-boolean result.
  *
  * @param left The left table
  * @param right The right table
@@ -818,6 +834,9 @@ std::unique_ptr<rmm::device_uvector<size_type>> conditional_left_semi_join(
  * for which there does not exist any row in the right table where the
  * predicate evaluates to true.
  *
+ * If the provided predicate returns NULL for a pair of pair of rows
+ * (left, right), that pair is not included in the output.
+ *
  * @code{.pseudo}
  * Left: {{0, 1, 2}}
  * Right: {{1, 2, 3}}
@@ -832,6 +851,7 @@ std::unique_ptr<rmm::device_uvector<size_type>> conditional_left_semi_join(
  *
  * @throw cudf::logic_error if number of elements in `left_keys` or `right_keys`
  * mismatch.
+ * @throw cudf::logic_error if the binary predicate outputs a non-boolean result.
  *
  * @param left The left table
  * @param right The right table

cpp/include/cudf/table/table_view.hpp

@@ -257,6 +257,11 @@ class mutable_table_view : public detail::table_view_base<mutable_column_view> {
   mutable_table_view(std::vector<mutable_table_view> const& views);
 };
 
+inline bool nullable(table_view const& view)
+{
+  return std::any_of(view.begin(), view.end(), [](auto const& col) { return col.nullable(); });
+}
+
 inline bool has_nulls(table_view const& view)
 {
   return std::any_of(view.begin(), view.end(), [](auto const& col) { return col.has_nulls(); });

cpp/src/ast/transform.cu

@@ -93,11 +93,8 @@ std::unique_ptr<column> compute_column(table_view const table,
   // If none of the input columns actually contain nulls, we can still use the
   // non-nullable version of the expression evaluation code path for
   // performance, so we capture that information as well.
-  auto const nullable =
-    std::any_of(table.begin(), table.end(), [](column_view c) { return c.nullable(); });
-  auto const has_nulls = nullable && std::any_of(table.begin(), table.end(), [](column_view c) {
-                           return c.nullable() && c.has_nulls();
-                         });
+  auto const nullable  = cudf::nullable(table);
+  auto const has_nulls = nullable && cudf::has_nulls(table);
 
   auto const plan = ast_plan{expr, table, has_nulls, stream, mr};
 

cpp/src/join/nested_loop_join.cuh

@@ -85,15 +85,8 @@ get_conditional_join_indices(table_view const& left,
   // If none of the input columns actually contain nulls, we can still use the
   // non-nullable version of the expression evaluation code path for
   // performance, so we capture that information as well.
-  auto const nullable =
-    std::any_of(left.begin(), left.end(), [](column_view c) { return c.nullable(); }) ||
-    std::any_of(right.begin(), right.end(), [](column_view c) { return c.nullable(); });
-  auto const has_nulls =
-    nullable &&
-    (std::any_of(
-       left.begin(), left.end(), [](column_view c) { return c.nullable() && c.has_nulls(); }) ||
-     std::any_of(
-       right.begin(), right.end(), [](column_view c) { return c.nullable() && c.has_nulls(); }));
+  auto const nullable  = cudf::nullable(left) || cudf::nullable(right);
+  auto const has_nulls = nullable && (cudf::has_nulls(left) || cudf::has_nulls(right));
 
   auto const plan = ast::detail::ast_plan{binary_pred, left, right, has_nulls, stream, mr};
   CUDF_EXPECTS(plan.output_type().id() == type_id::BOOL8,