Extracted out evaluators

pkg/yqlib/all_at_once_evaluator.go

@@ -0,0 +1,45 @@
+package yqlib
+
+import "container/list"
+
+/**
+	Loads all yaml documents of all files given into memory, then runs the given expression once.
+**/
+type Evaluator interface {
+	EvaluateFiles(expression string, filenames []string, printer Printer) error
+}
+
+type allAtOnceEvaluator struct {
+	treeNavigator DataTreeNavigator
+	treeCreator   PathTreeCreator
+}
+
+func NewAllAtOnceEvaluator() Evaluator {
+	return &allAtOnceEvaluator{treeNavigator: NewDataTreeNavigator(), treeCreator: NewPathTreeCreator()}
+}
+
+func (e *allAtOnceEvaluator) EvaluateFiles(expression string, filenames []string, printer Printer) error {
+	fileIndex := 0
+	node, err := treeCreator.ParsePath(expression)
+	if err != nil {
+		return err
+	}
+	var allDocuments *list.List = list.New()
+	for _, filename := range filenames {
+		reader, err := readStream(filename)
+		if err != nil {
+			return err
+		}
+		fileDocuments, err := readDocuments(reader, filename, fileIndex)
+		if err != nil {
+			return err
+		}
+		allDocuments.PushBackList(fileDocuments)
+		fileIndex = fileIndex + 1
+	}
+	matches, err := treeNavigator.GetMatchingNodes(allDocuments, node)
+	if err != nil {
+		return err
+	}
+	return printer.PrintResults(matches)
+}