// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you 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.
#pragma once
#include <algorithm>
#include <cstddef>
#include <memory>
#include <string>
#include <tuple>
#include <type_traits>
#include <utility>
#include <vector>
#include "arrow/array.h"
#include "arrow/array/builder_base.h"
#include "arrow/array/builder_binary.h"
#include "arrow/array/builder_nested.h"
#include "arrow/array/builder_primitive.h"
#include "arrow/chunked_array.h"
#include "arrow/compute/api.h"
#include "arrow/status.h"
#include "arrow/table.h"
#include "arrow/type_fwd.h"
#include "arrow/type_traits.h"
#include "arrow/util/checked_cast.h"
#include "arrow/util/macros.h"
namespace arrow {
class Schema;
namespace stl {
namespace internal {
template <typename T, typename = void>
struct is_optional_like : public std::false_type {};
template <typename T, typename = void>
struct is_dereferencable : public std::false_type {};
template <typename T>
struct is_dereferencable<T, arrow::internal::void_t<decltype(*std::declval<T>())>>
: public std::true_type {};
template <typename T>
struct is_optional_like<
T, typename std::enable_if<
std::is_constructible<bool, T>::value && is_dereferencable<T>::value &&
!std::is_array<typename std::remove_reference<T>::type>::value>::type>
: public std::true_type {};
template <size_t N, typename Tuple>
using BareTupleElement =
typename std::decay<typename std::tuple_element<N, Tuple>::type>::type;
} // namespace internal
template <typename T, typename R = void>
using enable_if_optional_like =
typename std::enable_if<internal::is_optional_like<T>::value, R>::type;
/// Traits meta class to map standard C/C++ types to equivalent Arrow types.
template <typename T, typename Enable = void>
struct ConversionTraits {};
/// Returns builder type for given standard C/C++ type.
template <typename CType>
using CBuilderType =
typename TypeTraits<typename ConversionTraits<CType>::ArrowType>::BuilderType;
/// Default implementation of AppendListValues.
///
/// This function can be specialized by user to take advantage of appending
/// contiguous ranges while appending. This default implementation will call
/// ConversionTraits<ValueCType>::AppendRow() for each value in the range.
template <typename ValueCType, typename Range>
inline Status AppendListValues(CBuilderType<ValueCType>& value_builder,
Range&& cell_range) {
for (auto const& value : cell_range) {
ARROW_RETURN_NOT_OK(ConversionTraits<ValueCType>::AppendRow(value_builder, value));
}
return Status::OK();
}
#define ARROW_STL_CONVERSION(CType_, ArrowType_) \
template <> \
struct ConversionTraits<CType_> : public CTypeTraits<CType_> { \
static Status AppendRow(typename TypeTraits<ArrowType_>::BuilderType& builder, \
CType_ cell) { \
return builder.Append(cell); \
} \
static CType_ GetEntry(const typename TypeTraits<ArrowType_>::ArrayType& array, \
size_t j) { \
return array.Value(j); \
} \
}; \
\
template <> \
inline Status AppendListValues<CType_, const std::vector<CType_>&>( \
typename TypeTraits<ArrowType_>::BuilderType & value_builder, \
const std::vector<CType_>& cell_range) { \
return value_builder.AppendValues(cell_range); \
}
ARROW_STL_CONVERSION(bool, BooleanType)
ARROW_STL_CONVERSION(int8_t, Int8Type)
ARROW_STL_CONVERSION(int16_t, Int16Type)
ARROW_STL_CONVERSION(int32_t, Int32Type)
ARROW_STL_CONVERSION(int64_t, Int64Type)
ARROW_STL_CONVERSION(uint8_t, UInt8Type)
ARROW_STL_CONVERSION(uint16_t, UInt16Type)
ARROW_STL_CONVERSION(uint32_t, UInt32Type)
ARROW_STL_CONVERSION(uint64_t, UInt64Type)
ARROW_STL_CONVERSION(float, FloatType)
ARROW_STL_CONVERSION(double, DoubleType)
template <>
struct ConversionTraits<std::string> : public CTypeTraits<std::string> {
static Status AppendRow(StringBuilder& builder, const std::string& cell) {
return builder.Append(cell);
}
static std::string GetEntry(const StringArray& array, size_t j) {
return array.GetString(j);
}
};
/// Append cell range elements as a single value to the list builder.
///
/// Cell range will be added to child builder using AppendListValues<ValueCType>()
/// if provided. AppendListValues<ValueCType>() has a default implementation, but
/// it can be specialized by users.
template <typename ValueCType, typename ListBuilderType, typename Range>
Status AppendCellRange(ListBuilderType& builder, Range&& cell_range) {
constexpr bool is_list_builder = std::is_same<ListBuilderType, ListBuilder>::value;
constexpr bool is_large_list_builder =
std::is_same<ListBuilderType, LargeListBuilder>::value;
static_assert(
is_list_builder || is_large_list_builder,
"Builder type must be either ListBuilder or LargeListBuilder for appending "
"multiple rows.");
using ChildBuilderType = CBuilderType<ValueCType>;
ARROW_RETURN_NOT_OK(builder.Append());
auto& value_builder =
::arrow::internal::checked_cast<ChildBuilderType&>(*builder.value_builder());
// XXX: Remove appended value before returning if status isn't OK?
return AppendListValues<ValueCType>(value_builder, std::forward<Range>(cell_range));
}
template <typename ValueCType>
struct ConversionTraits<std::vector<ValueCType>>
: public CTypeTraits<std::vector<ValueCType>> {
static Status AppendRow(ListBuilder& builder, const std::vector<ValueCType>& cell) {
return AppendCellRange<ValueCType>(builder, cell);
}
static std::vector<ValueCType> GetEntry(const ListArray& array, size_t j) {
using ElementArrayType =
typename TypeTraits<typename ConversionTraits<ValueCType>::ArrowType>::ArrayType;
const ElementArrayType& value_array =
::arrow::internal::checked_cast<const ElementArrayType&>(*array.values());
std::vector<ValueCType> vec(array.value_length(j));
for (int64_t i = 0; i < array.value_length(j); i++) {
vec[i] =
ConversionTraits<ValueCType>::GetEntry(value_array, array.value_offset(j) + i);
}
return vec;
}
};
template <class ValueCType, std::size_t N>
struct ConversionTraits<std::array<ValueCType, N>>
: public CTypeTraits<std::array<ValueCType, N>> {
static arrow::Status AppendRow(FixedSizeListBuilder& builder,
const std::array<ValueCType, N>& values) {
auto vb =
::arrow::internal::checked_cast<typename CTypeTraits<ValueCType>::BuilderType*>(
builder.value_builder());
ARROW_RETURN_NOT_OK(builder.Append());
return vb->AppendValues(values.data(), N);
}
static std::array<ValueCType, N> GetEntry(const ::arrow::FixedSizeListArray& array,
size_t j) {
using ElementArrayType = typename TypeTraits<
typename stl::ConversionTraits<ValueCType>::ArrowType>::ArrayType;
const ElementArrayType& value_array =
::arrow::internal::checked_cast<const ElementArrayType&>(*array.values());
std::array<ValueCType, N> arr;
for (size_t i = 0; i < N; i++) {
arr[i] = stl::ConversionTraits<ValueCType>::GetEntry(value_array,
array.value_offset(j) + i);
}
return arr;
}
};
template <typename Optional>
struct ConversionTraits<Optional, enable_if_optional_like<Optional>>
: public CTypeTraits<typename std::decay<decltype(*std::declval<Optional>())>::type> {
using OptionalInnerType =
typename std::decay<decltype(*std::declval<Optional>())>::type;
using typename CTypeTraits<OptionalInnerType>::ArrowType;
using CTypeTraits<OptionalInnerType>::type_singleton;
static Status AppendRow(typename TypeTraits<ArrowType>::BuilderType& builder,
const Optional& cell) {
if (cell) {
return ConversionTraits<OptionalInnerType>::AppendRow(builder, *cell);
} else {
return builder.AppendNull();
}
}
};
/// Build an arrow::Schema based upon the types defined in a std::tuple-like structure.
///
/// While the type information is available at compile-time, we still need to add the
/// column names at runtime, thus these methods are not constexpr.
template <typename Tuple, std::size_t N = std::tuple_size<Tuple>::value>
struct SchemaFromTuple {
using Element = internal::BareTupleElement<N - 1, Tuple>;
// Implementations that take a vector-like object for the column names.
/// Recursively build a vector of arrow::Field from the defined types.
///
/// In most cases MakeSchema is the better entrypoint for the Schema creation.
static std::vector<std::shared_ptr<Field>> MakeSchemaRecursion(
const std::vector<std::string>& names) {
std::vector<std::shared_ptr<Field>> ret =
SchemaFromTuple<Tuple, N - 1>::MakeSchemaRecursion(names);
auto type = ConversionTraits<Element>::type_singleton();
ret.push_back(field(names[N - 1], type, internal::is_optional_like<Element>::value));
return ret;
}
/// Build a Schema from the types of the tuple-like structure passed in as template
/// parameter assign the column names at runtime.
///
/// An example usage of this API can look like the following:
///
/// \code{.cpp}
/// using TupleType = std::tuple<int, std::vector<std::string>>;
/// std::shared_ptr<Schema> schema =
/// SchemaFromTuple<TupleType>::MakeSchema({"int_column", "list_of_strings_column"});
/// \endcode
static std::shared_ptr<Schema> MakeSchema(const std::vector<std::string>& names) {
return std::make_shared<Schema>(MakeSchemaRecursion(names));
}
// Implementations that take a tuple-like object for the column names.
/// Recursively build a vector of arrow::Field from the defined types.
///
/// In most cases MakeSchema is the better entrypoint for the Schema creation.
template <typename NamesTuple>
static std::vector<std::shared_ptr<Field>> MakeSchemaRecursionT(
const NamesTuple& names) {
using std::get;
std::vector<std::shared_ptr<Field>> ret =
SchemaFromTuple<Tuple, N - 1>::MakeSchemaRecursionT(names);
std::shared_ptr<DataType> type = ConversionTraits<Element>::type_singleton();
ret.push_back(
field(get<N - 1>(names), type, internal::is_optional_like<Element>::value));
return ret;
}
/// Build a Schema from the types of the tuple-like structure passed in as template
/// parameter assign the column names at runtime.
///
/// An example usage of this API can look like the following:
///
/// \code{.cpp}
/// using TupleType = std::tuple<int, std::vector<std::string>>;
/// std::shared_ptr<Schema> schema =
/// SchemaFromTuple<TupleType>::MakeSchema({"int_column", "list_of_strings_column"});
/// \endcode
template <typename NamesTuple>
static std::shared_ptr<Schema> MakeSchema(const NamesTuple& names) {
return std::make_shared<Schema>(MakeSchemaRecursionT<NamesTuple>(names));
}
};
template <typename Tuple>
struct SchemaFromTuple<Tuple, 0> {
static std::vector<std::shared_ptr<Field>> MakeSchemaRecursion(
const std::vector<std::string>& names) {
std::vector<std::shared_ptr<Field>> ret;
ret.reserve(names.size());
return ret;
}
template <typename NamesTuple>
static std::vector<std::shared_ptr<Field>> MakeSchemaRecursionT(
const NamesTuple& names) {
std::vector<std::shared_ptr<Field>> ret;
ret.reserve(std::tuple_size<NamesTuple>::value);
return ret;
}
};
namespace internal {
template <typename Tuple, std::size_t N = std::tuple_size<Tuple>::value>
struct CreateBuildersRecursive {
static Status Make(MemoryPool* pool,
std::vector<std::unique_ptr<ArrayBuilder>>* builders) {
using Element = BareTupleElement<N - 1, Tuple>;
std::shared_ptr<DataType> type = ConversionTraits<Element>::type_singleton();
ARROW_RETURN_NOT_OK(MakeBuilder(pool, type, &builders->at(N - 1)));
return CreateBuildersRecursive<Tuple, N - 1>::Make(pool, builders);
}
};
template <typename Tuple>
struct CreateBuildersRecursive<Tuple, 0> {
static Status Make(MemoryPool*, std::vector<std::unique_ptr<ArrayBuilder>>*) {
return Status::OK();
}
};
template <typename Tuple, std::size_t N = std::tuple_size<Tuple>::value>
struct RowIterator {
static Status Append(const std::vector<std::unique_ptr<ArrayBuilder>>& builders,
const Tuple& row) {
using std::get;
using Element = BareTupleElement<N - 1, Tuple>;
using BuilderType =
typename TypeTraits<typename ConversionTraits<Element>::ArrowType>::BuilderType;
BuilderType& builder =
::arrow::internal::checked_cast<BuilderType&>(*builders[N - 1]);
ARROW_RETURN_NOT_OK(ConversionTraits<Element>::AppendRow(builder, get<N - 1>(row)));
return RowIterator<Tuple, N - 1>::Append(builders, row);
}
};
template <typename Tuple>
struct RowIterator<Tuple, 0> {
static Status Append(const std::vector<std::unique_ptr<ArrayBuilder>>& builders,
const Tuple& row) {
return Status::OK();
}
};
template <typename Tuple, std::size_t N = std::tuple_size<Tuple>::value>
struct EnsureColumnTypes {
static Status Cast(const Table& table, std::shared_ptr<Table>* table_owner,
const compute::CastOptions& cast_options, compute::ExecContext* ctx,
std::reference_wrapper<const ::arrow::Table>* result) {
using Element = BareTupleElement<N - 1, Tuple>;
std::shared_ptr<DataType> expected_type = ConversionTraits<Element>::type_singleton();
if (!table.schema()->field(N - 1)->type()->Equals(*expected_type)) {
ARROW_ASSIGN_OR_RAISE(
Datum casted,
compute::Cast(table.column(N - 1), expected_type, cast_options, ctx));
auto new_field = table.schema()->field(N - 1)->WithType(expected_type);
ARROW_ASSIGN_OR_RAISE(*table_owner,
table.SetColumn(N - 1, new_field, casted.chunked_array()));
*result = **table_owner;
}
return EnsureColumnTypes<Tuple, N - 1>::Cast(result->get(), table_owner, cast_options,
ctx, result);
}
};
template <typename Tuple>
struct EnsureColumnTypes<Tuple, 0> {
static Status Cast(const Table& table, std::shared_ptr<Table>* table_owner,
const compute::CastOptions& cast_options, compute::ExecContext* ctx,
std::reference_wrapper<const ::arrow::Table>* result) {
return Status::OK();
}
};
template <typename Range, typename Tuple, std::size_t N = std::tuple_size<Tuple>::value>
struct TupleSetter {
static void Fill(const Table& table, Range* rows) {
using std::get;
using Element = typename std::tuple_element<N - 1, Tuple>::type;
using ArrayType =
typename TypeTraits<typename ConversionTraits<Element>::ArrowType>::ArrayType;
auto iter = rows->begin();
const ChunkedArray& chunked_array = *table.column(N - 1);
for (int i = 0; i < chunked_array.num_chunks(); i++) {
const ArrayType& array =
::arrow::internal::checked_cast<const ArrayType&>(*chunked_array.chunk(i));
for (int64_t j = 0; j < array.length(); j++) {
get<N - 1>(*iter++) = ConversionTraits<Element>::GetEntry(array, j);
}
}
return TupleSetter<Range, Tuple, N - 1>::Fill(table, rows);
}
};
template <typename Range, typename Tuple>
struct TupleSetter<Range, Tuple, 0> {
static void Fill(const Table& table, Range* rows) {}
};
} // namespace internal
template <typename Range>
Status TableFromTupleRange(MemoryPool* pool, Range&& rows,
const std::vector<std::string>& names,
std::shared_ptr<Table>* table) {
using row_type = typename std::iterator_traits<decltype(std::begin(rows))>::value_type;
constexpr std::size_t n_columns = std::tuple_size<row_type>::value;
std::shared_ptr<Schema> schema = SchemaFromTuple<row_type>::MakeSchema(names);
std::vector<std::unique_ptr<ArrayBuilder>> builders(n_columns);
ARROW_RETURN_NOT_OK(internal::CreateBuildersRecursive<row_type>::Make(pool, &builders));
for (auto const& row : rows) {
ARROW_RETURN_NOT_OK(internal::RowIterator<row_type>::Append(builders, row));
}
std::vector<std::shared_ptr<Array>> arrays;
for (auto const& builder : builders) {
std::shared_ptr<Array> array;
ARROW_RETURN_NOT_OK(builder->Finish(&array));
arrays.emplace_back(array);
}
*table = Table::Make(std::move(schema), std::move(arrays));
return Status::OK();
}
template <typename Range>
Status TupleRangeFromTable(const Table& table, const compute::CastOptions& cast_options,
compute::ExecContext* ctx, Range* rows) {
using row_type = typename std::decay<decltype(*std::begin(*rows))>::type;
constexpr std::size_t n_columns = std::tuple_size<row_type>::value;
if (table.schema()->num_fields() != n_columns) {
return Status::Invalid(
"Number of columns in the table does not match the width of the target: ",
table.schema()->num_fields(), " != ", n_columns);
}
if (std::size(*rows) != static_cast<size_t>(table.num_rows())) {
return Status::Invalid(
"Number of rows in the table does not match the size of the target: ",
table.num_rows(), " != ", std::size(*rows));
}
// Check that all columns have the correct type, otherwise cast them.
std::shared_ptr<Table> table_owner;
std::reference_wrapper<const ::arrow::Table> current_table(table);
ARROW_RETURN_NOT_OK(internal::EnsureColumnTypes<row_type>::Cast(
table, &table_owner, cast_options, ctx, ¤t_table));
internal::TupleSetter<Range, row_type>::Fill(current_table.get(), rows);
return Status::OK();
}
} // namespace stl
} // namespace arrow