110 lines
2.7 KiB
Go
110 lines
2.7 KiB
Go
// gomuks - A terminal Matrix client written in Go.
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// Copyright (C) 2020 Tulir Asokan
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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package ui
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import (
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"bytes"
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"fmt"
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"html"
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"io"
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"math/rand"
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"unicode"
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"github.com/rivo/uniseg"
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"github.com/russross/blackfriday/v2"
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)
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type RainbowRenderer struct {
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*blackfriday.HTMLRenderer
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sr *blackfriday.SPRenderer
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ColorID string
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}
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func Rand(n int) (str string) {
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b := make([]byte, n)
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rand.Read(b)
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str = fmt.Sprintf("%x", b)
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return
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}
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func NewRainbowRenderer(html *blackfriday.HTMLRenderer) *RainbowRenderer {
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return &RainbowRenderer{
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HTMLRenderer: html,
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sr: blackfriday.NewSmartypantsRenderer(html.Flags),
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ColorID: Rand(16),
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}
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}
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func (r *RainbowRenderer) RenderNode(w io.Writer, node *blackfriday.Node, entering bool) blackfriday.WalkStatus {
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if node.Type == blackfriday.Text {
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var buf bytes.Buffer
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if r.Flags&blackfriday.Smartypants != 0 {
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var tmp bytes.Buffer
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escapeHTML(&tmp, node.Literal)
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r.sr.Process(&buf, tmp.Bytes())
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} else {
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if node.Parent.Type == blackfriday.Link {
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escLink(&buf, node.Literal)
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} else {
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escapeHTML(&buf, node.Literal)
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}
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}
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graphemes := uniseg.NewGraphemes(buf.String())
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buf.Reset()
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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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buf.WriteRune(runes[0])
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}
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_, _ = fmt.Fprintf(&buf, "<font color=\"%s\">%s</font>", r.ColorID, graphemes.Str())
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}
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_, _ = w.Write(buf.Bytes())
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return blackfriday.GoToNext
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}
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return r.HTMLRenderer.RenderNode(w, node, entering)
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}
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// This stuff is copied directly from blackfriday
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var htmlEscaper = [256][]byte{
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'&': []byte("&"),
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'<': []byte("<"),
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'>': []byte(">"),
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'"': []byte("""),
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}
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func escapeHTML(w io.Writer, s []byte) {
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var start, end int
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for end < len(s) {
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escSeq := htmlEscaper[s[end]]
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if escSeq != nil {
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w.Write(s[start:end])
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w.Write(escSeq)
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start = end + 1
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}
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end++
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}
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if start < len(s) && end <= len(s) {
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w.Write(s[start:end])
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}
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}
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func escLink(w io.Writer, text []byte) {
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unesc := html.UnescapeString(string(text))
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escapeHTML(w, []byte(unesc))
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}
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