Support null value in CUDA array interface. (dmlc#8486) (dmlc#8499)

Author: hcho3

src/data/array_interface.h

@@ -101,7 +101,7 @@ class ArrayInterfaceHandler {
   template <typename PtrType>
   static PtrType GetPtrFromArrayData(Object::Map const &obj) {
     auto data_it = obj.find("data");
-    if (data_it == obj.cend()) {
+    if (data_it == obj.cend() || IsA<Null>(data_it->second)) {
       LOG(FATAL) << "Empty data passed in.";
     }
     auto p_data = reinterpret_cast<PtrType>(
@@ -111,25 +111,27 @@ class ArrayInterfaceHandler {
 
   static void Validate(Object::Map const &array) {
     auto version_it = array.find("version");
-    if (version_it == array.cend()) {
+    if (version_it == array.cend() || IsA<Null>(version_it->second)) {
       LOG(FATAL) << "Missing `version' field for array interface";
     }
     if (get<Integer const>(version_it->second) > 3) {
       LOG(FATAL) << ArrayInterfaceErrors::Version();
     }
 
     auto typestr_it = array.find("typestr");
-    if (typestr_it == array.cend()) {
+    if (typestr_it == array.cend() || IsA<Null>(typestr_it->second)) {
       LOG(FATAL) << "Missing `typestr' field for array interface";
     }
 
     auto typestr = get<String const>(typestr_it->second);
     CHECK(typestr.size() == 3 || typestr.size() == 4) << ArrayInterfaceErrors::TypestrFormat();
 
-    if (array.find("shape") == array.cend()) {
+    auto shape_it = array.find("shape");
+    if (shape_it == array.cend() || IsA<Null>(shape_it->second)) {
       LOG(FATAL) << "Missing `shape' field for array interface";
     }
-    if (array.find("data") == array.cend()) {
+    auto data_it = array.find("data");
+    if (data_it == array.cend() || IsA<Null>(data_it->second)) {
       LOG(FATAL) << "Missing `data' field for array interface";
     }
   }
@@ -139,8 +141,9 @@ class ArrayInterfaceHandler {
   static size_t ExtractMask(Object::Map const &column,
                             common::Span<RBitField8::value_type> *p_out) {
     auto &s_mask = *p_out;
-    if (column.find("mask") != column.cend()) {
-      auto const &j_mask = get<Object const>(column.at("mask"));
+    auto const &mask_it = column.find("mask");
+    if (mask_it != column.cend() && !IsA<Null>(mask_it->second)) {
+      auto const &j_mask = get<Object const>(mask_it->second);
       Validate(j_mask);
 
       auto p_mask = GetPtrFromArrayData<RBitField8::value_type *>(j_mask);
@@ -173,8 +176,9 @@ class ArrayInterfaceHandler {
       // assume 1 byte alignment.
       size_t const span_size = RBitField8::ComputeStorageSize(n_bits);
 
-      if (j_mask.find("strides") != j_mask.cend()) {
-        auto strides = get<Array const>(column.at("strides"));
+      auto strides_it = j_mask.find("strides");
+      if (strides_it != j_mask.cend() && !IsA<Null>(strides_it->second)) {
+        auto strides = get<Array const>(strides_it->second);
         CHECK_EQ(strides.size(), 1) << ArrayInterfaceErrors::Dimension(1);
         CHECK_EQ(get<Integer>(strides.at(0)), type_length) << ArrayInterfaceErrors::Contiguous();
       }
@@ -401,7 +405,9 @@ class ArrayInterface {
                             << "XGBoost doesn't support internal broadcasting.";
       }
     } else {
-      CHECK(array.find("mask") == array.cend()) << "Masked array is not yet supported.";
+      auto mask_it = array.find("mask");
+      CHECK(mask_it == array.cend() || IsA<Null>(mask_it->second))
+          << "Masked array is not yet supported.";
     }
 
     auto stream_it = array.find("stream");

tests/cpp/data/test_array_interface.cc

@@ -33,9 +33,8 @@ TEST(ArrayInterface, Error) {
   Json column { Object() };
   std::vector<Json> j_shape {Json(Integer(static_cast<Integer::Int>(kRows)))};
   column["shape"] = Array(j_shape);
-  std::vector<Json> j_data {
-    Json(Integer(reinterpret_cast<Integer::Int>(nullptr))),
-        Json(Boolean(false))};
+  std::vector<Json> j_data{Json(Integer(reinterpret_cast<Integer::Int>(nullptr))),
+                           Json(Boolean(false))};
 
   auto const& column_obj = get<Object>(column);
   std::string typestr{"<f4"};
@@ -45,6 +44,10 @@ TEST(ArrayInterface, Error) {
   EXPECT_THROW(ArrayInterfaceHandler::ExtractData(column_obj, n), dmlc::Error);
   column["version"] = 3;
   // missing data
+  EXPECT_THROW(ArrayInterfaceHandler::ExtractData(column_obj, n),
+               dmlc::Error);
+  // null data
+  column["data"] = Null{};
   EXPECT_THROW(ArrayInterfaceHandler::ExtractData(column_obj, n),
                dmlc::Error);
   column["data"] = j_data;
@@ -63,6 +66,11 @@ TEST(ArrayInterface, Error) {
       Json(Boolean(false))};
   column["data"] = j_data;
   EXPECT_NO_THROW(ArrayInterfaceHandler::ExtractData(column_obj, n));
+  // null data in mask
+  column["mask"] = Object{};
+  column["mask"]["data"] = Null{};
+  common::Span<RBitField8::value_type> s_mask;
+  EXPECT_THROW(ArrayInterfaceHandler::ExtractMask(column_obj, &s_mask), dmlc::Error);
 }
 
 TEST(ArrayInterface, GetElement) {