mirror of https://github.com/mikefarah/yq.git
111 lines
2.7 KiB
Go
111 lines
2.7 KiB
Go
package yqlib
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import (
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"container/list"
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"io"
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"os"
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yaml "gopkg.in/yaml.v3"
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)
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// A yaml expression evaluator that runs the expression multiple times for each given yaml document.
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// Uses less memory than loading all documents and running the expression once, but this cannot process
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// cross document expressions.
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type StreamEvaluator interface {
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Evaluate(filename string, reader io.Reader, node *ExpressionNode, printer Printer) error
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EvaluateFiles(expression string, filenames []string, printer Printer) error
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EvaluateNew(expression string, printer Printer) error
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}
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type streamEvaluator struct {
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treeNavigator DataTreeNavigator
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treeCreator ExpressionParser
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fileIndex int
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}
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func NewStreamEvaluator() StreamEvaluator {
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return &streamEvaluator{treeNavigator: NewDataTreeNavigator(), treeCreator: NewExpressionParser()}
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}
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func (s *streamEvaluator) EvaluateNew(expression string, printer Printer) error {
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node, err := s.treeCreator.ParseExpression(expression)
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if err != nil {
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return err
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}
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candidateNode := &CandidateNode{
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Document: 0,
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Filename: "",
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Node: &yaml.Node{Tag: "!!null"},
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FileIndex: 0,
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}
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inputList := list.New()
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inputList.PushBack(candidateNode)
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matches, errorParsing := s.treeNavigator.GetMatchingNodes(inputList, node)
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if errorParsing != nil {
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return errorParsing
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}
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return printer.PrintResults(matches)
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}
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func (s *streamEvaluator) EvaluateFiles(expression string, filenames []string, printer Printer) error {
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node, err := s.treeCreator.ParseExpression(expression)
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if err != nil {
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return err
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}
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for _, filename := range filenames {
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reader, err := readStream(filename)
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if err != nil {
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return err
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}
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err = s.Evaluate(filename, reader, node, printer)
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if err != nil {
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return err
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}
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switch reader := reader.(type) {
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case *os.File:
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safelyCloseFile(reader)
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}
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}
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return nil
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}
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func (s *streamEvaluator) Evaluate(filename string, reader io.Reader, node *ExpressionNode, printer Printer) error {
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var currentIndex uint
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decoder := yaml.NewDecoder(reader)
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for {
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var dataBucket yaml.Node
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errorReading := decoder.Decode(&dataBucket)
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if errorReading == io.EOF {
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s.fileIndex = s.fileIndex + 1
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return nil
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} else if errorReading != nil {
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return errorReading
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}
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candidateNode := &CandidateNode{
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Document: currentIndex,
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Filename: filename,
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Node: &dataBucket,
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FileIndex: s.fileIndex,
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}
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inputList := list.New()
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inputList.PushBack(candidateNode)
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matches, errorParsing := s.treeNavigator.GetMatchingNodes(inputList, node)
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if errorParsing != nil {
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return errorParsing
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}
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err := printer.PrintResults(matches)
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if err != nil {
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return err
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}
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currentIndex = currentIndex + 1
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}
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}
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