arrow/extension/json.h

0001 // Licensed to the Apache Software Foundation (ASF) under one
0002 // or more contributor license agreements.  See the NOTICE file
0003 // distributed with this work for additional information
0004 // regarding copyright ownership.  The ASF licenses this file
0005 // to you under the Apache License, Version 2.0 (the
0006 // "License"); you may not use this file except in compliance
0007 // with the License.  You may obtain a copy of the License at
0008 //
0009 //   http://www.apache.org/licenses/LICENSE-2.0
0010 //
0011 // Unless required by applicable law or agreed to in writing,
0012 // software distributed under the License is distributed on an
0013 // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
0014 // KIND, either express or implied.  See the License for the
0015 // specific language governing permissions and limitations
0016 // under the License.
0017
0018 #pragma once
0019
0020 #include <stdexcept>
0021 #include <string>
0022
0023 #include "arrow/extension_type.h"
0024 #include "arrow/result.h"
0025 #include "arrow/type_fwd.h"
0026 #include "arrow/util/visibility.h"
0027
0028 namespace arrow::extension {
0029
0030 /// \brief Concrete type class for variable-size JSON data, utf8-encoded.
0031 class ARROW_EXPORT JsonExtensionType : public ExtensionType {
0032  public:
0033   explicit JsonExtensionType(const std::shared_ptr<DataType>& storage_type)
0034       : ExtensionType(storage_type), storage_type_(storage_type) {}
0035
0036   std::string extension_name() const override { return "arrow.json"; }
0037
0038   bool ExtensionEquals(const ExtensionType& other) const override;
0039
0040   Result<std::shared_ptr<DataType>> Deserialize(
0041       std::shared_ptr<DataType> storage_type,
0042       const std::string& serialized_data) const override;
0043
0044   std::string Serialize() const override;
0045
0046   std::shared_ptr<Array> MakeArray(std::shared_ptr<ArrayData> data) const override;
0047
0048   static Result<std::shared_ptr<DataType>> Make(std::shared_ptr<DataType> storage_type);
0049
0050   static bool IsSupportedStorageType(Type::type type_id);
0051
0052  private:
0053   std::shared_ptr<DataType> storage_type_;
0054 };
0055
0056 /// \brief Return a JsonExtensionType instance.
0057 ARROW_EXPORT std::shared_ptr<DataType> json(
0058     std::shared_ptr<DataType> storage_type = utf8());
0059
0060 }  // namespace arrow::extension