yq/pkg/yqlib/printer_writer.go

package yqlib

import (
	"bufio"
	"fmt"
	"io"
)

type printerWriter interface {
	GetWriter(node *CandidateNode, index int) (*bufio.Writer, error)
}

type singlePrinterWriter struct {
	bufferedWriter *bufio.Writer
}

func NewSinglePrinterWriter(writer io.Writer) printerWriter {
	return &singlePrinterWriter{
		bufferedWriter: bufio.NewWriter(writer),
	}
}

func (sp *singlePrinterWriter) GetWriter(node *CandidateNode, i int) (*bufio.Writer, error) {
	return sp.bufferedWriter, nil
}

type multiPrintWriter struct {
	treeNavigator  DataTreeNavigator
	nameExpression *ExpressionNode
	extension      string
}

func (sp *multiPrintWriter) GetWriter(node *CandidateNode, index int) (*bufio.Writer, error) {
	name := ""

	if sp.nameExpression != nil {
		context := Context{MatchingNodes: node.AsList()}
		result, err := sp.treeNavigator.GetMatchingNodes(context, sp.nameExpression)
		if err != nil {
			return nil, err
		}
		if result.MatchingNodes.Len() > 0 {
			name = result.MatchingNodes.Front().Value.(*CandidateNode).Node.Value
		}
	}
	if name == "" {
		name = fmt.Sprintf("%v.%v", index, sp.extension)
	} else {
		name = fmt.Sprintf("%v.%v", name, sp.extension)
	}

}