Added union methods to the Reader

getml · Dec 1, 2024 · 1f22054 · 1f22054
1 parent 8db12dc
commit 1f22054
Show file tree

Hide file tree

Showing 2 changed files with 38 additions and 2 deletions.
diff --git a/include/rfl/avro/Reader.hpp b/include/rfl/avro/Reader.hpp
@@ -27,12 +27,17 @@ struct Reader {
     const avro_value_t* val_;
   };
 
+  struct AVROInputUnion {
+    const avro_value_t* val_;
+  };
+
   struct AVROInputVar {
     const avro_value_t* val_;
   };
 
   using InputArrayType = AVROInputArray;
   using InputObjectType = AVROInputObject;
+  using InputUnionType = AVROInputUnion;
   using InputVarType = AVROInputVar;
 
   template <class T>
@@ -45,6 +50,9 @@ struct Reader {
   rfl::Result<InputVarType> get_field_from_object(
       const std::string& _name, const InputObjectType& _obj) const noexcept;
 
+  rfl::Result<InputVarType> get_field_from_union(
+      const size_t _index, const InputUnionType& _union) const noexcept;
+
   bool is_empty(const InputVarType& _var) const noexcept;
 
   template <class T>
@@ -133,6 +141,8 @@ struct Reader {
   rfl::Result<InputObjectType> to_object(
       const InputVarType& _var) const noexcept;
 
+  rfl::Result<InputUnionType> to_union(const InputVarType& _var) const noexcept;
+
   template <class ArrayReader>
   std::optional<Error> read_array(const ArrayReader& _array_reader,
                                   const InputArrayType& _arr) const noexcept {
@@ -163,6 +173,23 @@ struct Reader {
     return std::nullopt;
   }
 
+  template <class VariantType, class VariantParserType>
+  rfl::Result<VariantType> to_variant(
+      const size_t _index, const InputUnionType& _union) const noexcept {
+    int disc = 0;
+    auto err = avro_value_get_discriminant(_union.val_, &disc);
+    if (err) {
+      return Error("Could not get the discriminant.");
+    }
+    avro_value_t value;
+    err = avro_value_get_current_branch(_union.val_, &value);
+    if (err) {
+      return Error("Could not cast the union type.");
+    }
+    return VariantParserType::parse(static_cast<size_t>(disc),
+                                    InputVarType{&value});
+  }
+
   template <class T>
   rfl::Result<T> use_custom_constructor(
       const InputVarType& _var) const noexcept {

diff --git a/src/rfl/avro/Reader.cpp b/src/rfl/avro/Reader.cpp
@@ -4,12 +4,12 @@ namespace rfl::avro {
 
 rfl::Result<Reader::InputVarType> Reader::get_field_from_array(
     const size_t _idx, const InputArrayType& _arr) const noexcept {
-  return Error("TODO");
+  return Error("This should never be called - Avro has explicit union types.");
 }
 
 rfl::Result<Reader::InputVarType> Reader::get_field_from_object(
     const std::string& _name, const InputObjectType& _obj) const noexcept {
-  return Error("TODO");
+  return Error("This should never be called - Avro has explicit union types.");
 }
 
 bool Reader::is_empty(const InputVarType& _var) const noexcept {
@@ -24,6 +24,15 @@ rfl::Result<Reader::InputArrayType> Reader::to_array(
   return InputArrayType{_var.val_};
 }
 
+rfl::Result<Reader::InputUnionType> Reader::to_union(
+    const InputVarType& _var) const noexcept {
+  const auto type = avro_value_get_type(_var.val_);
+  if (type != AVRO_UNION) {
+    return Error("Could not cast to a union.");
+  }
+  return InputUnionType{_var.val_};
+}
+
 rfl::Result<Reader::InputObjectType> Reader::to_object(
     const InputVarType& _var) const noexcept {
   const auto type = avro_value_get_type(_var.val_);