140 lines
4.1 KiB
Go
140 lines
4.1 KiB
Go
//
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// Copyright (c) 2019 Ted Unangst <tedu@tedunangst.com>
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//
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// Permission to use, copy, modify, and distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice appear in all copies.
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//
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// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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package main
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import (
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"fmt"
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"regexp"
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"strings"
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"golang.org/x/net/html"
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"humungus.tedunangst.com/r/webs/synlight"
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)
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var re_bolder = regexp.MustCompile(`(^|\W)\*\*((?s:.*?))\*\*($|\W)`)
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var re_italicer = regexp.MustCompile(`(^|\W)\*((?s:.*?))\*($|\W)`)
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var re_bigcoder = regexp.MustCompile("```(.*)\n?((?s:.*?))\n?```\n?")
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var re_coder = regexp.MustCompile("`([^`]*)`")
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var re_quoter = regexp.MustCompile(`(?m:^> (.*)\n?)`)
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var re_link = regexp.MustCompile(`.?.?https?://[^\s"]+[\w/)!]`)
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var re_zerolink = regexp.MustCompile(`\[([^]]*)\]\(([^)]*\)?)\)`)
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var re_imgfix = regexp.MustCompile(`<img ([^>]*)>`)
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var lighter = synlight.New(synlight.Options{Format: synlight.HTML})
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func markitzero(s string) string {
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// prepare the string
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s = strings.TrimSpace(s)
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s = strings.Replace(s, "\r", "", -1)
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// save away the code blocks so we don't mess them up further
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var bigcodes, lilcodes, images []string
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s = re_bigcoder.ReplaceAllStringFunc(s, func(code string) string {
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bigcodes = append(bigcodes, code)
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return "``````"
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})
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s = re_coder.ReplaceAllStringFunc(s, func(code string) string {
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lilcodes = append(lilcodes, code)
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return "`x`"
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})
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s = re_imgfix.ReplaceAllStringFunc(s, func(img string) string {
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images = append(images, img)
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return "<img x>"
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})
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// fewer side effects than html.EscapeString
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buf := make([]byte, 0, len(s))
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for _, c := range []byte(s) {
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switch c {
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case '&':
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buf = append(buf, []byte("&")...)
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case '<':
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buf = append(buf, []byte("<")...)
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case '>':
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buf = append(buf, []byte(">")...)
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default:
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buf = append(buf, c)
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}
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}
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s = string(buf)
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// mark it zero
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s = re_link.ReplaceAllStringFunc(s, linkreplacer)
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s = re_zerolink.ReplaceAllString(s, `<a href="$2">$1</a>`)
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s = re_bolder.ReplaceAllString(s, "$1<b>$2</b>$3")
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s = re_italicer.ReplaceAllString(s, "$1<i>$2</i>$3")
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s = re_quoter.ReplaceAllString(s, "<blockquote>$1</blockquote><p>")
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// restore images
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s = strings.Replace(s, "<img x>", "<img x>", -1)
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s = re_imgfix.ReplaceAllStringFunc(s, func(string) string {
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img := images[0]
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images = images[1:]
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return img
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})
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// now restore the code blocks
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s = re_coder.ReplaceAllStringFunc(s, func(string) string {
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code := lilcodes[0]
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lilcodes = lilcodes[1:]
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code = html.EscapeString(code)
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return code
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})
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s = re_bigcoder.ReplaceAllStringFunc(s, func(string) string {
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code := bigcodes[0]
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bigcodes = bigcodes[1:]
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m := re_bigcoder.FindStringSubmatch(code)
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return "<pre><code>" + lighter.HighlightString(m[2], m[1]) + "</code></pre><p>"
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})
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s = re_coder.ReplaceAllString(s, "<code>$1</code>")
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// some final fixups
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s = strings.Replace(s, "\n", "<br>", -1)
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s = strings.Replace(s, "<br><blockquote>", "<blockquote>", -1)
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s = strings.Replace(s, "<br><pre>", "<pre>", -1)
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s = strings.Replace(s, "<p><br>", "<p>", -1)
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return s
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}
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func linkreplacer(url string) string {
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if url[0:2] == "](" {
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return url
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}
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prefix := ""
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for !strings.HasPrefix(url, "http") {
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prefix += url[0:1]
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url = url[1:]
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}
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addparen := false
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adddot := false
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if strings.HasSuffix(url, ")") && strings.IndexByte(url, '(') == -1 {
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url = url[:len(url)-1]
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addparen = true
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}
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if strings.HasSuffix(url, ".") {
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url = url[:len(url)-1]
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adddot = true
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}
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url = fmt.Sprintf(`<a href="%s">%s</a>`, url, url)
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if adddot {
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url += "."
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}
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if addparen {
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url += ")"
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}
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return prefix + url
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}
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