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forgejo/vendor/github.com/yuin/goldmark/renderer/renderer.go
zeripath 27757714d0 Change markdown rendering from blackfriday to goldmark (#9533)
* Move to goldmark

Markdown rendering moved from blackfriday to the goldmark.

Multiple subtle changes required to the goldmark extensions to keep
current rendering and defaults.

Can go further with goldmark linkify and have this work within markdown
rendering making the link processor unnecessary.

Need to think about how to go about allowing extensions - at present it
seems that these would be hard to do without recompilation.

* linter fixes

Co-authored-by: Lauris BH <lauris@nix.lv>
2019-12-31 03:53:28 +02:00

174 lines
4.5 KiB
Go

// Package renderer renders the given AST to certain formats.
package renderer
import (
"bufio"
"io"
"sync"
"github.com/yuin/goldmark/ast"
"github.com/yuin/goldmark/util"
)
// A Config struct is a data structure that holds configuration of the Renderer.
type Config struct {
Options map[OptionName]interface{}
NodeRenderers util.PrioritizedSlice
}
// NewConfig returns a new Config
func NewConfig() *Config {
return &Config{
Options: map[OptionName]interface{}{},
NodeRenderers: util.PrioritizedSlice{},
}
}
// An OptionName is a name of the option.
type OptionName string
// An Option interface is a functional option type for the Renderer.
type Option interface {
SetConfig(*Config)
}
type withNodeRenderers struct {
value []util.PrioritizedValue
}
func (o *withNodeRenderers) SetConfig(c *Config) {
c.NodeRenderers = append(c.NodeRenderers, o.value...)
}
// WithNodeRenderers is a functional option that allow you to add
// NodeRenderers to the renderer.
func WithNodeRenderers(ps ...util.PrioritizedValue) Option {
return &withNodeRenderers{ps}
}
type withOption struct {
name OptionName
value interface{}
}
func (o *withOption) SetConfig(c *Config) {
c.Options[o.name] = o.value
}
// WithOption is a functional option that allow you to set
// an arbitrary option to the parser.
func WithOption(name OptionName, value interface{}) Option {
return &withOption{name, value}
}
// A SetOptioner interface sets given option to the object.
type SetOptioner interface {
// SetOption sets given option to the object.
// Unacceptable options may be passed.
// Thus implementations must ignore unacceptable options.
SetOption(name OptionName, value interface{})
}
// NodeRendererFunc is a function that renders a given node.
type NodeRendererFunc func(writer util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error)
// A NodeRenderer interface offers NodeRendererFuncs.
type NodeRenderer interface {
// RendererFuncs registers NodeRendererFuncs to given NodeRendererFuncRegisterer.
RegisterFuncs(NodeRendererFuncRegisterer)
}
// A NodeRendererFuncRegisterer registers
type NodeRendererFuncRegisterer interface {
// Register registers given NodeRendererFunc to this object.
Register(ast.NodeKind, NodeRendererFunc)
}
// A Renderer interface renders given AST node to given
// writer with given Renderer.
type Renderer interface {
Render(w io.Writer, source []byte, n ast.Node) error
// AddOptions adds given option to this renderer.
AddOptions(...Option)
}
type renderer struct {
config *Config
options map[OptionName]interface{}
nodeRendererFuncsTmp map[ast.NodeKind]NodeRendererFunc
maxKind int
nodeRendererFuncs []NodeRendererFunc
initSync sync.Once
}
// NewRenderer returns a new Renderer with given options.
func NewRenderer(options ...Option) Renderer {
config := NewConfig()
for _, opt := range options {
opt.SetConfig(config)
}
r := &renderer{
options: map[OptionName]interface{}{},
config: config,
nodeRendererFuncsTmp: map[ast.NodeKind]NodeRendererFunc{},
}
return r
}
func (r *renderer) AddOptions(opts ...Option) {
for _, opt := range opts {
opt.SetConfig(r.config)
}
}
func (r *renderer) Register(kind ast.NodeKind, v NodeRendererFunc) {
r.nodeRendererFuncsTmp[kind] = v
if int(kind) > r.maxKind {
r.maxKind = int(kind)
}
}
// Render renders the given AST node to the given writer with the given Renderer.
func (r *renderer) Render(w io.Writer, source []byte, n ast.Node) error {
r.initSync.Do(func() {
r.options = r.config.Options
r.config.NodeRenderers.Sort()
l := len(r.config.NodeRenderers)
for i := l - 1; i >= 0; i-- {
v := r.config.NodeRenderers[i]
nr, _ := v.Value.(NodeRenderer)
if se, ok := v.Value.(SetOptioner); ok {
for oname, ovalue := range r.options {
se.SetOption(oname, ovalue)
}
}
nr.RegisterFuncs(r)
}
r.nodeRendererFuncs = make([]NodeRendererFunc, r.maxKind+1)
for kind, nr := range r.nodeRendererFuncsTmp {
r.nodeRendererFuncs[kind] = nr
}
r.config = nil
r.nodeRendererFuncsTmp = nil
})
writer, ok := w.(util.BufWriter)
if !ok {
writer = bufio.NewWriter(w)
}
err := ast.Walk(n, func(n ast.Node, entering bool) (ast.WalkStatus, error) {
s := ast.WalkStatus(ast.WalkContinue)
var err error
f := r.nodeRendererFuncs[n.Kind()]
if f != nil {
s, err = f(writer, source, n, entering)
}
return s, err
})
if err != nil {
return err
}
return writer.Flush()
}