// Copyright 2019 The Hugo Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package goldmark
import (
"bytes"
"sync"
"github.com/spf13/cast"
"github.com/gohugoio/hugo/markup/converter/hooks"
"github.com/yuin/goldmark"
"github.com/yuin/goldmark/ast"
"github.com/yuin/goldmark/renderer"
"github.com/yuin/goldmark/renderer/html"
"github.com/yuin/goldmark/util"
)
var _ renderer.SetOptioner = (*hookedRenderer)(nil)
func newLinkRenderer() renderer.NodeRenderer {
r := &hookedRenderer{
Config: html.Config{
Writer: html.DefaultWriter,
},
}
return r
}
func newLinks() goldmark.Extender {
return &links{}
}
type attributesHolder struct {
// What we get from Goldmark.
astAttributes []ast.Attribute
// What we send to the the render hooks.
attributesInit sync.Once
attributes map[string]string
}
func (a *attributesHolder) Attributes() map[string]string {
a.attributesInit.Do(func() {
a.attributes = make(map[string]string)
for _, attr := range a.astAttributes {
a.attributes[string(attr.Name)] = string(util.EscapeHTML(attr.Value.([]byte)))
}
})
return a.attributes
}
type linkContext struct {
page interface{}
destination string
title string
text string
plainText string
}
func (ctx linkContext) Destination() string {
return ctx.destination
}
func (ctx linkContext) Resolved() bool {
return false
}
func (ctx linkContext) Page() interface{} {
return ctx.page
}
func (ctx linkContext) Text() string {
return ctx.text
}
func (ctx linkContext) PlainText() string {
return ctx.plainText
}
func (ctx linkContext) Title() string {
return ctx.title
}
type headingContext struct {
page interface{}
level int
anchor string
text string
plainText string
*attributesHolder
}
func (ctx headingContext) Page() interface{} {
return ctx.page
}
func (ctx headingContext) Level() int {
return ctx.level
}
func (ctx headingContext) Anchor() string {
return ctx.anchor
}
func (ctx headingContext) Text() string {
return ctx.text
}
func (ctx headingContext) PlainText() string {
return ctx.plainText
}
type hookedRenderer struct {
html.Config
}
func (r *hookedRenderer) SetOption(name renderer.OptionName, value interface{}) {
r.Config.SetOption(name, value)
}
// RegisterFuncs implements NodeRenderer.RegisterFuncs.
func (r *hookedRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
reg.Register(ast.KindLink, r.renderLink)
reg.Register(ast.KindImage, r.renderImage)
reg.Register(ast.KindHeading, r.renderHeading)
}
func (r *hookedRenderer) renderAttributesForNode(w util.BufWriter, node ast.Node) {
renderAttributes(w, false, node.Attributes()...)
}
var (
// Attributes with special meaning that does not make sense to render in HTML.
attributeExcludes = map[string]bool{
"linenos": true,
"hl_lines": true,
"linenostart": true,
}
)
func renderAttributes(w util.BufWriter, skipClass bool, attributes ...ast.Attribute) {
for _, attr := range attributes {
if skipClass && bytes.Equal(attr.Name, []byte("class")) {
continue
}
if attributeExcludes[string(attr.Name)] {
continue
}
_, _ = w.WriteString(" ")
_, _ = w.Write(attr.Name)
_, _ = w.WriteString(`="`)
switch v := attr.Value.(type) {
case []byte:
_, _ = w.Write(util.EscapeHTML(v))
default:
w.WriteString(cast.ToString(v))
}
_ = w.WriteByte('"')
}
}
// Fall back to the default Goldmark render funcs. Method below borrowed from:
// https://github.com/yuin/goldmark/blob/b611cd333a492416b56aa8d94b04a67bf0096ab2/renderer/html/html.go#L404
func (r *hookedRenderer) renderDefaultImage(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
if !entering {
return ast.WalkContinue, nil
}
n := node.(*ast.Image)
_, _ = w.WriteString("![`)
_, _ = w.Write(n.Text(source))
_ = w.WriteByte('](\"") "`)
r.Writer.Write(w, n.Title)
_ = w.WriteByte('")
")
} else {
_, _ = w.WriteString(">")
}
return ast.WalkSkipChildren, nil
}
func (r *hookedRenderer) renderImage(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
n := node.(*ast.Image)
var h hooks.Renderers
ctx, ok := w.(*renderContext)
if ok {
h = ctx.RenderContext().RenderHooks
ok = h.ImageRenderer != nil
}
if !ok {
return r.renderDefaultImage(w, source, node, entering)
}
if entering {
// Store the current pos so we can capture the rendered text.
ctx.pos = ctx.Buffer.Len()
return ast.WalkContinue, nil
}
text := ctx.Buffer.Bytes()[ctx.pos:]
ctx.Buffer.Truncate(ctx.pos)
err := h.ImageRenderer.RenderLink(
w,
linkContext{
page: ctx.DocumentContext().Document,
destination: string(n.Destination),
title: string(n.Title),
text: string(text),
plainText: string(n.Text(source)),
},
)
ctx.AddIdentity(h.ImageRenderer)
return ast.WalkContinue, err
}
// Fall back to the default Goldmark render funcs. Method below borrowed from:
// https://github.com/yuin/goldmark/blob/b611cd333a492416b56aa8d94b04a67bf0096ab2/renderer/html/html.go#L404
func (r *hookedRenderer) renderDefaultLink(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
n := node.(*ast.Link)
if entering {
_, _ = w.WriteString("')
} else {
_, _ = w.WriteString("")
}
return ast.WalkContinue, nil
}
func (r *hookedRenderer) renderLink(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
n := node.(*ast.Link)
var h hooks.Renderers
ctx, ok := w.(*renderContext)
if ok {
h = ctx.RenderContext().RenderHooks
ok = h.LinkRenderer != nil
}
if !ok {
return r.renderDefaultLink(w, source, node, entering)
}
if entering {
// Store the current pos so we can capture the rendered text.
ctx.pos = ctx.Buffer.Len()
return ast.WalkContinue, nil
}
text := ctx.Buffer.Bytes()[ctx.pos:]
ctx.Buffer.Truncate(ctx.pos)
err := h.LinkRenderer.RenderLink(
w,
linkContext{
page: ctx.DocumentContext().Document,
destination: string(n.Destination),
title: string(n.Title),
text: string(text),
plainText: string(n.Text(source)),
},
)
// TODO(bep) I have a working branch that fixes these rather confusing identity types,
// but for now it's important that it's not .GetIdentity() that's added here,
// to make sure we search the entire chain on changes.
ctx.AddIdentity(h.LinkRenderer)
return ast.WalkContinue, err
}
func (r *hookedRenderer) renderDefaultHeading(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
n := node.(*ast.Heading)
if entering {
_, _ = w.WriteString("')
} else {
_, _ = w.WriteString("\n")
}
return ast.WalkContinue, nil
}
func (r *hookedRenderer) renderHeading(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
n := node.(*ast.Heading)
var h hooks.Renderers
ctx, ok := w.(*renderContext)
if ok {
h = ctx.RenderContext().RenderHooks
ok = h.HeadingRenderer != nil
}
if !ok {
return r.renderDefaultHeading(w, source, node, entering)
}
if entering {
// Store the current pos so we can capture the rendered text.
ctx.pos = ctx.Buffer.Len()
return ast.WalkContinue, nil
}
text := ctx.Buffer.Bytes()[ctx.pos:]
ctx.Buffer.Truncate(ctx.pos)
// All ast.Heading nodes are guaranteed to have an attribute called "id"
// that is an array of bytes that encode a valid string.
anchori, _ := n.AttributeString("id")
anchor := anchori.([]byte)
err := h.HeadingRenderer.RenderHeading(
w,
headingContext{
page: ctx.DocumentContext().Document,
level: n.Level,
anchor: string(anchor),
text: string(text),
plainText: string(n.Text(source)),
attributesHolder: &attributesHolder{astAttributes: n.Attributes()},
},
)
ctx.AddIdentity(h.HeadingRenderer)
return ast.WalkContinue, err
}
type links struct {
}
// Extend implements goldmark.Extender.
func (e *links) Extend(m goldmark.Markdown) {
m.Renderer().AddOptions(renderer.WithNodeRenderers(
util.Prioritized(newLinkRenderer(), 100),
))
}