yq/pkg/yqlib/printer.go

package yqlib

import (
	"bufio"
	"container/list"
	"io"

	"gopkg.in/yaml.v3"
)

type Printer interface {
	PrintResults(matchingNodes *list.List, writer io.Writer) error
}

type resultsPrinter struct {
	outputToJSON       bool
	unwrapScalar       bool
	colorsEnabled      bool
	indent             int
	printDocSeparators bool
}

func NewPrinter(outputToJSON bool, unwrapScalar bool, colorsEnabled bool, indent int, printDocSeparators bool) Printer {
	return &resultsPrinter{outputToJSON, unwrapScalar, colorsEnabled, indent, printDocSeparators}
}

func (p *resultsPrinter) printNode(node *yaml.Node, writer io.Writer) error {
	var encoder Encoder
	if node.Kind == yaml.ScalarNode && p.unwrapScalar && !p.outputToJSON {
		return p.writeString(writer, node.Value+"\n")
	}
	if p.outputToJSON {
		encoder = NewJsonEncoder(writer, p.indent)
	} else {
		encoder = NewYamlEncoder(writer, p.indent, p.colorsEnabled)
	}
	return encoder.Encode(node)
}

func (p *resultsPrinter) writeString(writer io.Writer, txt string) error {
	_, errorWriting := writer.Write([]byte(txt))
	return errorWriting
}

func (p *resultsPrinter) PrintResults(matchingNodes *list.List, writer io.Writer) error {

	bufferedWriter := bufio.NewWriter(writer)
	defer safelyFlush(bufferedWriter)

	if matchingNodes.Len() == 0 {
		log.Debug("no matching results, nothing to print")
		return nil
	}

	var previousDocIndex uint = 0

	for el := matchingNodes.Front(); el != nil; el = el.Next() {
		mappedDoc := el.Value.(*CandidateNode)

		if previousDocIndex != mappedDoc.Document && p.printDocSeparators {
			p.writeString(bufferedWriter, "---\n")
		}

		if err := p.printNode(mappedDoc.Node, bufferedWriter); err != nil {
			return err
		}

		previousDocIndex = mappedDoc.Document
	}

	return nil
}