Added NDJSON decoder (#1281)

pkg/yqlib/decoder_json.go

@@ -0,0 +1,85 @@
+package yqlib
+
+import (
+	"fmt"
+	"io"
+
+	"github.com/goccy/go-json"
+	yaml "gopkg.in/yaml.v3"
+)
+
+type jsonDecoder struct {
+	decoder json.Decoder
+}
+
+func NewJSONDecoder() Decoder {
+	return &jsonDecoder{}
+}
+
+func (dec *jsonDecoder) Init(reader io.Reader) {
+	dec.decoder = *json.NewDecoder(reader)
+}
+
+func (dec *jsonDecoder) Decode(rootYamlNode *yaml.Node) error {
+
+	var dataBucket interface{}
+	log.Debug("going to decode")
+	err := dec.decoder.Decode(&dataBucket)
+	if err != nil {
+		return err
+	}
+	node, err := dec.convertToYamlNode(dataBucket)
+
+	if err != nil {
+		return err
+	}
+	rootYamlNode.Kind = yaml.DocumentNode
+	rootYamlNode.Content = []*yaml.Node{node}
+	return nil
+}
+
+func (dec *jsonDecoder) convertToYamlNode(data interface{}) (*yaml.Node, error) {
+	switch data := data.(type) {
+	case nil:
+		return createScalarNode(nil, "null"), nil
+	case float64, float32:
+		// json decoder returns ints as float.
+		return parseSnippet(fmt.Sprintf("%v", data))
+	case int, int64, int32, string, bool:
+		return createScalarNode(data, fmt.Sprintf("%v", data)), nil
+	case map[string]interface{}:
+		return dec.parseMap(data)
+	case []interface{}:
+		return dec.parseArray(data)
+	default:
+		return nil, fmt.Errorf("unrecognised type :(")
+	}
+}
+
+func (dec *jsonDecoder) parseMap(dataMap map[string]interface{}) (*yaml.Node, error) {
+
+	var yamlMap = &yaml.Node{Kind: yaml.MappingNode}
+
+	for key, value := range dataMap {
+		yamlValue, err := dec.convertToYamlNode(value)
+		if err != nil {
+			return nil, err
+		}
+		yamlMap.Content = append(yamlMap.Content, createScalarNode(key, fmt.Sprintf("%v", key)), yamlValue)
+	}
+	return yamlMap, nil
+}
+
+func (dec *jsonDecoder) parseArray(dataArray []interface{}) (*yaml.Node, error) {
+
+	var yamlMap = &yaml.Node{Kind: yaml.SequenceNode}
+
+	for _, value := range dataArray {
+		yamlValue, err := dec.convertToYamlNode(value)
+		if err != nil {
+			return nil, err
+		}
+		yamlMap.Content = append(yamlMap.Content, yamlValue)
+	}
+	return yamlMap, nil
+}