mirror of
https://github.com/tulir/gomuks.git
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120 lines
3.1 KiB
Go
120 lines
3.1 KiB
Go
// Copyright (c) 2024 Tulir Asokan
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this
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// file, You can obtain one at http://mozilla.org/MPL/2.0/.
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package rainbow
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import (
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"fmt"
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"unicode"
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"github.com/rivo/uniseg"
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"github.com/yuin/goldmark"
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"github.com/yuin/goldmark/ast"
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"github.com/yuin/goldmark/renderer"
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"github.com/yuin/goldmark/renderer/html"
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"github.com/yuin/goldmark/util"
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"go.mau.fi/util/random"
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)
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// Extension is a goldmark extension that adds rainbow text coloring to the HTML renderer.
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var Extension = &extRainbow{}
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type extRainbow struct{}
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type rainbowRenderer struct {
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HardWraps bool
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ColorID string
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}
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var defaultRB = &rainbowRenderer{HardWraps: true, ColorID: random.String(16)}
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func (er *extRainbow) Extend(m goldmark.Markdown) {
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m.Renderer().AddOptions(renderer.WithNodeRenderers(util.Prioritized(defaultRB, 0)))
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}
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func (rb *rainbowRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
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reg.Register(ast.KindText, rb.renderText)
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reg.Register(ast.KindString, rb.renderString)
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}
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type rainbowBufWriter struct {
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util.BufWriter
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ColorID string
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}
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func (rbw rainbowBufWriter) WriteString(s string) (int, error) {
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i := 0
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graphemes := uniseg.NewGraphemes(s)
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for graphemes.Next() {
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runes := graphemes.Runes()
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if len(runes) == 1 && unicode.IsSpace(runes[0]) {
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i2, err := rbw.BufWriter.WriteRune(runes[0])
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i += i2
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if err != nil {
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return i, err
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}
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continue
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}
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i2, err := fmt.Fprintf(rbw.BufWriter, "<font color=\"%s\">%s</font>", rbw.ColorID, graphemes.Str())
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i += i2
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if err != nil {
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return i, err
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}
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}
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return i, nil
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}
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func (rbw rainbowBufWriter) Write(data []byte) (int, error) {
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return rbw.WriteString(string(data))
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}
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func (rbw rainbowBufWriter) WriteByte(c byte) error {
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_, err := rbw.WriteRune(rune(c))
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return err
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}
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func (rbw rainbowBufWriter) WriteRune(r rune) (int, error) {
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if unicode.IsSpace(r) {
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return rbw.BufWriter.WriteRune(r)
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} else {
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return fmt.Fprintf(rbw.BufWriter, "<font color=\"%s\">%c</font>", rbw.ColorID, r)
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}
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}
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func (rb *rainbowRenderer) renderText(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
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if !entering {
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return ast.WalkContinue, nil
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}
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n := node.(*ast.Text)
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segment := n.Segment
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if n.IsRaw() {
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html.DefaultWriter.RawWrite(rainbowBufWriter{w, rb.ColorID}, segment.Value(source))
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} else {
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html.DefaultWriter.Write(rainbowBufWriter{w, rb.ColorID}, segment.Value(source))
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if n.HardLineBreak() || (n.SoftLineBreak() && rb.HardWraps) {
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_, _ = w.WriteString("<br>\n")
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} else if n.SoftLineBreak() {
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_ = w.WriteByte('\n')
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}
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}
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return ast.WalkContinue, nil
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}
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func (rb *rainbowRenderer) renderString(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
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if !entering {
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return ast.WalkContinue, nil
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}
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n := node.(*ast.String)
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if n.IsCode() {
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_, _ = w.Write(n.Value)
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} else {
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if n.IsRaw() {
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html.DefaultWriter.RawWrite(rainbowBufWriter{w, rb.ColorID}, n.Value)
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} else {
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html.DefaultWriter.Write(rainbowBufWriter{w, rb.ColorID}, n.Value)
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}
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}
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return ast.WalkContinue, nil
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}
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