yq/pkg/yqlib/all_at_once_evaluator.go
2021-02-11 10:58:40 +11:00

53 lines
1.5 KiB
Go

package yqlib
import "container/list"
// A yaml expression evaluator that runs the expression once against all files/nodes in memory.
type Evaluator interface {
EvaluateFiles(expression string, filenames []string, printer Printer) error
// Runs the expression once against the list of candidate nodes, returns the
// resulting nodes.
EvaluateNodes(expression string, inputCandidateNodes *list.List) (*list.List, error)
}
type allAtOnceEvaluator struct {
treeNavigator DataTreeNavigator
treeCreator PathTreeCreator
}
func NewAllAtOnceEvaluator() Evaluator {
return &allAtOnceEvaluator{treeNavigator: NewDataTreeNavigator(), treeCreator: NewPathTreeCreator()}
}
func (e *allAtOnceEvaluator) EvaluateNodes(expression string, inputCandidates *list.List) (*list.List, error) {
node, err := treeCreator.ParsePath(expression)
if err != nil {
return nil, err
}
return treeNavigator.GetMatchingNodes(inputCandidates, node)
}
func (e *allAtOnceEvaluator) EvaluateFiles(expression string, filenames []string, printer Printer) error {
fileIndex := 0
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 := e.EvaluateNodes(expression, allDocuments)
if err != nil {
return err
}
return printer.PrintResults(matches)
}