[chore/bugfix] Switch markdown from blackfriday to goldmark (#1267)

Co-authored-by: Autumn! <autumnull@posteo.net>

vendor/github.com/yuin/goldmark/markdown.go

@@ -0,0 +1,140 @@
+// Package goldmark implements functions to convert markdown text to a desired format.
+package goldmark
+
+import (
+	"github.com/yuin/goldmark/parser"
+	"github.com/yuin/goldmark/renderer"
+	"github.com/yuin/goldmark/renderer/html"
+	"github.com/yuin/goldmark/text"
+	"github.com/yuin/goldmark/util"
+	"io"
+)
+
+// DefaultParser returns a new Parser that is configured by default values.
+func DefaultParser() parser.Parser {
+	return parser.NewParser(parser.WithBlockParsers(parser.DefaultBlockParsers()...),
+		parser.WithInlineParsers(parser.DefaultInlineParsers()...),
+		parser.WithParagraphTransformers(parser.DefaultParagraphTransformers()...),
+	)
+}
+
+// DefaultRenderer returns a new Renderer that is configured by default values.
+func DefaultRenderer() renderer.Renderer {
+	return renderer.NewRenderer(renderer.WithNodeRenderers(util.Prioritized(html.NewRenderer(), 1000)))
+}
+
+var defaultMarkdown = New()
+
+// Convert interprets a UTF-8 bytes source in Markdown and
+// write rendered contents to a writer w.
+func Convert(source []byte, w io.Writer, opts ...parser.ParseOption) error {
+	return defaultMarkdown.Convert(source, w, opts...)
+}
+
+// A Markdown interface offers functions to convert Markdown text to
+// a desired format.
+type Markdown interface {
+	// Convert interprets a UTF-8 bytes source in Markdown and write rendered
+	// contents to a writer w.
+	Convert(source []byte, writer io.Writer, opts ...parser.ParseOption) error
+
+	// Parser returns a Parser that will be used for conversion.
+	Parser() parser.Parser
+
+	// SetParser sets a Parser to this object.
+	SetParser(parser.Parser)
+
+	// Parser returns a Renderer that will be used for conversion.
+	Renderer() renderer.Renderer
+
+	// SetRenderer sets a Renderer to this object.
+	SetRenderer(renderer.Renderer)
+}
+
+// Option is a functional option type for Markdown objects.
+type Option func(*markdown)
+
+// WithExtensions adds extensions.
+func WithExtensions(ext ...Extender) Option {
+	return func(m *markdown) {
+		m.extensions = append(m.extensions, ext...)
+	}
+}
+
+// WithParser allows you to override the default parser.
+func WithParser(p parser.Parser) Option {
+	return func(m *markdown) {
+		m.parser = p
+	}
+}
+
+// WithParserOptions applies options for the parser.
+func WithParserOptions(opts ...parser.Option) Option {
+	return func(m *markdown) {
+		m.parser.AddOptions(opts...)
+	}
+}
+
+// WithRenderer allows you to override the default renderer.
+func WithRenderer(r renderer.Renderer) Option {
+	return func(m *markdown) {
+		m.renderer = r
+	}
+}
+
+// WithRendererOptions applies options for the renderer.
+func WithRendererOptions(opts ...renderer.Option) Option {
+	return func(m *markdown) {
+		m.renderer.AddOptions(opts...)
+	}
+}
+
+type markdown struct {
+	parser     parser.Parser
+	renderer   renderer.Renderer
+	extensions []Extender
+}
+
+// New returns a new Markdown with given options.
+func New(options ...Option) Markdown {
+	md := &markdown{
+		parser:     DefaultParser(),
+		renderer:   DefaultRenderer(),
+		extensions: []Extender{},
+	}
+	for _, opt := range options {
+		opt(md)
+	}
+	for _, e := range md.extensions {
+		e.Extend(md)
+	}
+	return md
+}
+
+func (m *markdown) Convert(source []byte, writer io.Writer, opts ...parser.ParseOption) error {
+	reader := text.NewReader(source)
+	doc := m.parser.Parse(reader, opts...)
+	return m.renderer.Render(writer, source, doc)
+}
+
+func (m *markdown) Parser() parser.Parser {
+	return m.parser
+}
+
+func (m *markdown) SetParser(v parser.Parser) {
+	m.parser = v
+}
+
+func (m *markdown) Renderer() renderer.Renderer {
+	return m.renderer
+}
+
+func (m *markdown) SetRenderer(v renderer.Renderer) {
+	m.renderer = v
+}
+
+// An Extender interface is used for extending Markdown.
+type Extender interface {
+	// Extend extends the Markdown.
+	Extend(Markdown)
+}