Decoder Properties (#1099)

* Decoder Properties

* Added properties round trip test

* Fixed property decode for github actions

* Refactored XML test to use common functions

* Switched formatScenario parameter order for more readablity

pkg/yqlib/decoder_properties.go

@@ -0,0 +1,121 @@
+package yqlib
+
+import (
+	"bytes"
+	"io"
+	"strconv"
+	"strings"
+
+	"github.com/magiconair/properties"
+	"gopkg.in/yaml.v3"
+)
+
+type propertiesDecoder struct {
+	reader   io.Reader
+	finished bool
+	d        DataTreeNavigator
+}
+
+func NewPropertiesDecoder() Decoder {
+	return &propertiesDecoder{d: NewDataTreeNavigator(), finished: false}
+}
+
+func (dec *propertiesDecoder) Init(reader io.Reader) {
+	dec.reader = reader
+	dec.finished = false
+}
+
+func parsePropKey(key string) []interface{} {
+	pathStrArray := strings.Split(key, ".")
+	path := make([]interface{}, len(pathStrArray))
+	for i, pathStr := range pathStrArray {
+		num, err := strconv.ParseInt(pathStr, 10, 32)
+		if err == nil {
+			path[i] = num
+		} else {
+			path[i] = pathStr
+		}
+	}
+	return path
+}
+
+func (dec *propertiesDecoder) processComment(c string) string {
+	if c == "" {
+		return ""
+	}
+	return "# " + c
+}
+
+func (dec *propertiesDecoder) applyProperty(properties *properties.Properties, context Context, key string) error {
+	value, _ := properties.Get(key)
+	path := parsePropKey(key)
+
+	rhsNode := &yaml.Node{
+		Value:       value,
+		Tag:         "!!str",
+		Kind:        yaml.ScalarNode,
+		LineComment: dec.processComment(properties.GetComment(key)),
+	}
+
+	rhsNode.Tag = guessTagFromCustomType(rhsNode)
+
+	rhsCandidateNode := &CandidateNode{
+		Path: path,
+		Node: rhsNode,
+	}
+
+	assignmentOp := &Operation{OperationType: assignOpType, Preferences: assignPreferences{}}
+
+	rhsOp := &Operation{OperationType: valueOpType, CandidateNode: rhsCandidateNode}
+
+	assignmentOpNode := &ExpressionNode{
+		Operation: assignmentOp,
+		LHS:       createTraversalTree(path, traversePreferences{}, false),
+		RHS:       &ExpressionNode{Operation: rhsOp},
+	}
+
+	_, err := dec.d.GetMatchingNodes(context, assignmentOpNode)
+	return err
+}
+
+func (dec *propertiesDecoder) Decode(rootYamlNode *yaml.Node) error {
+	if dec.finished {
+		return io.EOF
+	}
+	buf := new(bytes.Buffer)
+
+	if _, err := buf.ReadFrom(dec.reader); err != nil {
+		return err
+	}
+	if buf.Len() == 0 {
+		dec.finished = true
+		return io.EOF
+	}
+	properties, err := properties.LoadString(buf.String())
+	if err != nil {
+		return err
+	}
+
+	rootMap := &CandidateNode{
+		Node: &yaml.Node{
+			Kind: yaml.MappingNode,
+			Tag:  "!!map",
+		},
+	}
+
+	context := Context{}
+	context = context.SingleChildContext(rootMap)
+
+	for _, key := range properties.Keys() {
+		if err := dec.applyProperty(properties, context, key); err != nil {
+			return err
+		}
+
+	}
+
+	rootYamlNode.Kind = yaml.DocumentNode
+	rootYamlNode.Content = []*yaml.Node{rootMap.Node}
+	dec.finished = true
+	return nil
+
+}