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// 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.
package extensions
import (
"fmt"
"reflect"
"slices"
"github.com/apache/arrow-go/v18/arrow"
"github.com/apache/arrow-go/v18/arrow/array"
"github.com/apache/arrow-go/v18/internal/json"
"github.com/apache/arrow-go/v18/parquet/schema"
)
var jsonSupportedStorageTypes = []arrow.DataType{
arrow.BinaryTypes.String,
arrow.BinaryTypes.LargeString,
arrow.BinaryTypes.StringView,
}
// JSONType represents a UTF-8 encoded JSON string as specified in RFC8259.
type JSONType struct {
arrow.ExtensionBase
}
// ParquetLogicalType implements pqarrow.ExtensionCustomParquetType.
func (b *JSONType) ParquetLogicalType() schema.LogicalType {
return schema.JSONLogicalType{}
}
// NewJSONType creates a new JSONType with the specified storage type.
// storageType must be one of String, LargeString, StringView.
func NewJSONType(storageType arrow.DataType) (*JSONType, error) {
if !slices.Contains(jsonSupportedStorageTypes, storageType) {
return nil, fmt.Errorf("unsupported storage type for JSON extension type: %s", storageType)
}
return &JSONType{ExtensionBase: arrow.ExtensionBase{Storage: storageType}}, nil
}
func (b *JSONType) ArrayType() reflect.Type { return reflect.TypeOf(JSONArray{}) }
func (b *JSONType) Deserialize(storageType arrow.DataType, data string) (arrow.ExtensionType, error) {
if !(data == "" || data == "{}") {
return nil, fmt.Errorf("serialized metadata for JSON extension type must be '' or '{}', found: %s", data)
}
return NewJSONType(storageType)
}
func (b *JSONType) ExtensionEquals(other arrow.ExtensionType) bool {
return b.ExtensionName() == other.ExtensionName() && arrow.TypeEqual(b.Storage, other.StorageType())
}
func (b *JSONType) ExtensionName() string { return "arrow.json" }
func (b *JSONType) Serialize() string { return "" }
func (b *JSONType) String() string {
return fmt.Sprintf("extension<%s[storage_type=%s]>", b.ExtensionName(), b.Storage)
}
// JSONArray is logically an array of UTF-8 encoded JSON strings.
// Its values are unmarshaled to native Go values.
type JSONArray struct {
array.ExtensionArrayBase
}
func (a *JSONArray) String() string {
b, err := a.MarshalJSON()
if err != nil {
panic(fmt.Sprintf("failed marshal JSONArray: %s", err))
}
return string(b)
}
func (a *JSONArray) Value(i int) any {
val := a.ValueBytes(i)
var res any
if err := json.Unmarshal(val, &res); err != nil {
panic(err)
}
return res
}
func (a *JSONArray) ValueStr(i int) string {
return string(a.ValueBytes(i))
}
func (a *JSONArray) ValueBytes(i int) []byte {
// convert to json.RawMessage, set to nil if elem isNull.
val := a.ValueJSON(i)
// simply returns wrapped bytes, or null if val is nil.
b, err := val.MarshalJSON()
if err != nil {
panic(err)
}
return b
}
// ValueJSON wraps the underlying string value as a json.RawMessage,
// or returns nil if the array value is null.
func (a *JSONArray) ValueJSON(i int) json.RawMessage {
var val json.RawMessage
if a.IsValid(i) {
val = json.RawMessage(a.Storage().(array.StringLike).Value(i))
}
return val
}
// MarshalJSON implements json.Marshaler.
// Marshaling json.RawMessage is a no-op, except that nil values will
// be marshaled as a JSON null.
func (a *JSONArray) MarshalJSON() ([]byte, error) {
values := make([]json.RawMessage, a.Len())
for i := 0; i < a.Len(); i++ {
values[i] = a.ValueJSON(i)
}
return json.Marshal(values)
}
// GetOneForMarshal implements arrow.Array.
func (a *JSONArray) GetOneForMarshal(i int) interface{} {
return a.ValueJSON(i)
}
var (
_ arrow.ExtensionType = (*JSONType)(nil)
_ array.ExtensionArray = (*JSONArray)(nil)
)
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