refactored

pkg/yqlib/data_tree_navigator.go

@@ -0,0 +1,48 @@
+package yqlib
+
+import (
+	"fmt"
+
+	"container/list"
+
+	"gopkg.in/op/go-logging.v1"
+)
+
+type dataTreeNavigator struct {
+	navigationPrefs NavigationPrefs
+}
+
+type NavigationPrefs struct {
+	FollowAlias bool
+}
+
+type DataTreeNavigator interface {
+	// given a list of CandidateEntities and a pathNode,
+	// this will process the list against the given pathNode and return
+	// a new list of matching candidates
+	GetMatchingNodes(matchingNodes *list.List, pathNode *PathTreeNode) (*list.List, error)
+}
+
+func NewDataTreeNavigator(navigationPrefs NavigationPrefs) DataTreeNavigator {
+	return &dataTreeNavigator{navigationPrefs}
+}
+
+func (d *dataTreeNavigator) GetMatchingNodes(matchingNodes *list.List, pathNode *PathTreeNode) (*list.List, error) {
+	if pathNode == nil {
+		log.Debugf("getMatchingNodes - nothing to do")
+		return matchingNodes, nil
+	}
+	log.Debugf("Processing Op: %v", pathNode.Operation.toString())
+	if log.IsEnabledFor(logging.DEBUG) {
+		for el := matchingNodes.Front(); el != nil; el = el.Next() {
+			log.Debug(NodeToString(el.Value.(*CandidateNode)))
+		}
+	}
+	log.Debug(">>")
+	handler := pathNode.Operation.OperationType.Handler
+	if handler != nil {
+		return handler(d, matchingNodes, pathNode)
+	}
+	return nil, fmt.Errorf("Unknown operator %v", pathNode.Operation.OperationType)
+
+}