Rebase

Author: emkornfield

cpp/src/arrow/array/builder_primitive.h

@@ -95,7 +95,7 @@ class NumericBuilder : public ArrayBuilder {
   value_type operator[](int64_t index) const { return GetValue(index); }
 
   value_type& operator[](int64_t index) {
-    return reinterpret_cast<value_type*>(data_->mutable_data())[index];
+    return reinterpret_cast<value_type*>(data_builder_.mutable_data())[index];
   }
 
   /// \brief Append a sequence of elements in one shot

cpp/src/arrow/compute/kernels/hash.cc

@@ -104,10 +104,12 @@ class UniqueAction : public ActionBase {
 // ----------------------------------------------------------------------
 // Count values implementation (see HashKernel for description of methods)
 
-class ValueCountsAction {
+class ValueCountsAction : ActionBase {
  public:
+  using ActionBase::ActionBase;
+
   ValueCountsAction(const std::shared_ptr<DataType>& type, MemoryPool* pool)
-      : count_builder_(pool) {}
+      : ActionBase(type, pool), count_builder_(pool) {}
 
   Status Reserve(const int64_t length) {
     // builder size is independent of input array size.
@@ -122,6 +124,8 @@ class ValueCountsAction {
   // or incur the cost of memory copies.
   Status Flush(Datum* out) { return Status::OK(); }
 
+  std::shared_ptr<DataType> out_type() const { return type_; }
+
   // Return the counts corresponding the MemoTable keys.
   Status FlushFinal(Datum* out) {
     std::shared_ptr<ArrayData> result;