1717
1818#include " arrow/array/array_nested.h"
1919
20- #include < atomic>
2120#include < cstddef>
2221#include < cstdint>
2322#include < memory>
23+ #include < mutex>
2424#include < string>
2525#include < utility>
2626#include < vector>
@@ -1004,10 +1004,18 @@ Result<std::shared_ptr<Array>> FixedSizeListArray::Flatten(
10041004// ----------------------------------------------------------------------
10051005// Struct
10061006
1007+ struct StructArray ::Impl {
1008+ std::mutex mutex;
1009+ ArrayVector boxed_fields;
1010+ };
1011+
1012+ StructArray::~StructArray () = default ;
1013+
10071014StructArray::StructArray (
const std::shared_ptr<ArrayData>& data) {
10081015 ARROW_CHECK_EQ (data->type ->id (), Type::STRUCT);
10091016 SetData (data);
1010- boxed_fields_.resize (data->child_data .size ());
1017+ impl_ = std::make_unique<Impl>();
1018+ impl_->boxed_fields .resize (data_->child_data .size ());
10111019}
10121020
10131021StructArray::StructArray (const std::shared_ptr<DataType>& type, int64_t length,
@@ -1016,10 +1024,12 @@ StructArray::StructArray(const std::shared_ptr<DataType>& type, int64_t length,
10161024 int64_t offset) {
10171025 ARROW_CHECK_EQ (type->id (), Type::STRUCT);
10181026 SetData (ArrayData::Make (type, length, {std::move (null_bitmap)}, null_count, offset));
1027+ data_->child_data .reserve (children.size ());
10191028 for (const auto & child : children) {
10201029 data_->child_data .push_back (child->data ());
10211030 }
1022- boxed_fields_.resize (children.size ());
1031+ impl_ = std::make_unique<Impl>();
1032+ impl_->boxed_fields .resize (data_->child_data .size ());
10231033}
10241034
10251035Result<std::shared_ptr<StructArray>> StructArray::Make (
@@ -1069,27 +1079,32 @@ const StructType* StructArray::struct_type() const {
10691079 return checked_cast<const StructType*>(data_->type .get ());
10701080}
10711081
1082+ std::shared_ptr<Array> StructArray::MakeBoxedField (int i) const {
1083+ std::shared_ptr<ArrayData> field_data;
1084+ if (data_->offset != 0 || data_->child_data [i]->length != data_->length ) {
1085+ field_data = data_->child_data [i]->Slice (data_->offset , data_->length );
1086+ } else {
1087+ field_data = data_->child_data [i];
1088+ }
1089+ return MakeArray (field_data);
1090+ }
1091+
10721092const ArrayVector& StructArray::fields () const {
1093+ std::lock_guard lock (impl_->mutex );
10731094 for (int i = 0 ; i < num_fields (); ++i) {
1074- (void )field (i);
1095+ if (impl_->boxed_fields [i] == nullptr ) {
1096+ impl_->boxed_fields [i] = MakeBoxedField (i);
1097+ }
10751098 }
1076- return boxed_fields_ ;
1099+ return impl_-> boxed_fields ;
10771100}
10781101
10791102const std::shared_ptr<Array>&
StructArray::field (
int i)
const {
1080- std::shared_ptr<Array> result = std::atomic_load (&boxed_fields_[i]);
1081- if (!result) {
1082- std::shared_ptr<ArrayData> field_data;
1083- if (data_->offset != 0 || data_->child_data [i]->length != data_->length ) {
1084- field_data = data_->child_data [i]->Slice (data_->offset , data_->length );
1085- } else {
1086- field_data = data_->child_data [i];
1087- }
1088- result = MakeArray (field_data);
1089- std::atomic_store (&boxed_fields_[i], std::move (result));
1090- return boxed_fields_[i];
1103+ std::lock_guard lock (impl_->mutex );
1104+ if (impl_->boxed_fields [i] == nullptr ) {
1105+ impl_->boxed_fields [i] = MakeBoxedField (i);
10911106 }
1092- return boxed_fields_ [i];
1107+ return impl_-> boxed_fields [i];
10931108}
10941109
10951110std::shared_ptr<Array> StructArray::GetFieldByName (const std::string& name) const {
@@ -1177,14 +1192,24 @@ Result<std::shared_ptr<Array>> StructArray::GetFlattenedField(int index,
11771192// ----------------------------------------------------------------------
11781193// UnionArray
11791194
1195+ struct UnionArray ::Impl {
1196+ std::mutex mutex;
1197+ ArrayVector boxed_fields;
1198+ };
1199+
1200+ UnionArray::UnionArray () = default ;
1201+ UnionArray::~UnionArray () = default ;
1202+
11801203void UnionArray::SetData (std::shared_ptr<ArrayData> data) {
11811204 this ->Array ::SetData (std::move (data));
11821205
11831206 union_type_ = checked_cast<const UnionType*>(data_->type .get ());
11841207
11851208 ARROW_CHECK_GE (data_->buffers .size (), 2 );
11861209 raw_type_codes_ = data->GetValuesSafe <int8_t >(1 );
1187- boxed_fields_.resize (data_->child_data .size ());
1210+
1211+ impl_ = std::make_unique<Impl>();
1212+ impl_->boxed_fields .resize (data_->child_data .size ());
11881213}
11891214
11901215void SparseUnionArray::SetData (std::shared_ptr<ArrayData> data) {
@@ -1198,16 +1223,16 @@ void SparseUnionArray::SetData(std::shared_ptr<ArrayData> data) {
11981223
11991224void DenseUnionArray::SetData (
const std::shared_ptr<ArrayData>& data) {
12001225 this ->UnionArray ::SetData (data);
1201-
12021226 ARROW_CHECK_EQ (data_->type ->id (), Type::DENSE_UNION);
12031227 ARROW_CHECK_EQ (data_->buffers .size (), 3 );
12041228
12051229 // No validity bitmap
12061230 ARROW_CHECK_EQ (data_->buffers [0 ], nullptr );
1207-
12081231 raw_value_offsets_ = data->GetValuesSafe <int32_t >(2 );
12091232}
12101233
1234+ SparseUnionArray::~SparseUnionArray () = default ;
1235+
12111236SparseUnionArray::SparseUnionArray (std::shared_ptr<ArrayData> data) {
12121237 SetData (std::move (data));
12131238}
@@ -1261,6 +1286,8 @@ Result<std::shared_ptr<Array>> SparseUnionArray::GetFlattenedField(
12611286 return MakeArray (child_data);
12621287}
12631288
1289+ DenseUnionArray::~DenseUnionArray () = default ;
1290+
12641291DenseUnionArray::DenseUnionArray (
const std::shared_ptr<ArrayData>& data) {
12651292 SetData (data);
12661293}
@@ -1352,26 +1379,29 @@ Result<std::shared_ptr<Array>> SparseUnionArray::Make(
13521379 return std::make_shared<SparseUnionArray>(std::move (internal_data));
13531380}
13541381
1382+ std::shared_ptr<Array> UnionArray::MakeBoxedField (int i) const {
1383+ std::shared_ptr<ArrayData> child_data = data_->child_data [i]->Copy ();
1384+ if (mode () == UnionMode::SPARSE) {
1385+ // Sparse union: need to adjust child if union is sliced
1386+ // (for dense unions, the need to lookup through the offsets
1387+ // makes this unnecessary)
1388+ if (data_->offset != 0 || child_data->length > data_->length ) {
1389+ child_data = child_data->Slice (data_->offset , data_->length );
1390+ }
1391+ }
1392+ return MakeArray (child_data);
1393+ }
1394+
13551395std::shared_ptr<Array> UnionArray::field (int i) const {
1356- if (i < 0 ||
1357- static_cast <decltype (boxed_fields_)::size_type>(i) >= boxed_fields_.size ()) {
1396+ if (i < 0 || i >= num_fields ()) {
13581397 return nullptr ;
13591398 }
1360- std::shared_ptr<Array> result = std::atomic_load (&boxed_fields_[i]);
1361- if (!result) {
1362- std::shared_ptr<ArrayData> child_data = data_->child_data [i]->Copy ();
1363- if (mode () == UnionMode::SPARSE) {
1364- // Sparse union: need to adjust child if union is sliced
1365- // (for dense unions, the need to lookup through the offsets
1366- // makes this unnecessary)
1367- if (data_->offset != 0 || child_data->length > data_->length ) {
1368- child_data = child_data->Slice (data_->offset , data_->length );
1369- }
1370- }
1371- result = MakeArray (child_data);
1372- std::atomic_store (&boxed_fields_[i], result);
1399+
1400+ std::lock_guard lock (impl_->mutex );
1401+ if (impl_->boxed_fields [i] == nullptr ) {
1402+ impl_->boxed_fields [i] = MakeBoxedField (i);
13731403 }
1374- return result ;
1404+ return impl_-> boxed_fields [i] ;
13751405}
13761406
13771407} // namespace arrow
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