Fix regression in HTML handling (telegram). Closes #734

* Revert back to blackfriday v1
* Add testing

1 files changed, 334 insertions, 0 deletions

diff --git a/vendor/github.com/russross/blackfriday/latex.go b/vendor/github.com/russross/blackfriday/latex.go
new file mode 100644
index 00000000..3d30d094
--- /dev/null
+++ b/vendor/github.com/russross/blackfriday/latex.go
@@ -0,0 +1,334 @@
+//
+// Blackfriday Markdown Processor
+// Available at http://github.com/russross/blackfriday
+//
+// Copyright © 2011 Russ Ross <russ@russross.com>.
+// Distributed under the Simplified BSD License.
+// See README.md for details.
+//
+
+//
+//
+// LaTeX rendering backend
+//
+//
+
+package blackfriday
+
+import (
+	"bytes"
+	"strings"
+)
+
+// Latex is a type that implements the Renderer interface for LaTeX output.
+//
+// Do not create this directly, instead use the LatexRenderer function.
+type Latex struct {
+}
+
+// LatexRenderer creates and configures a Latex object, which
+// satisfies the Renderer interface.
+//
+// flags is a set of LATEX_* options ORed together (currently no such options
+// are defined).
+func LatexRenderer(flags int) Renderer {
+	return &Latex{}
+}
+
+func (options *Latex) GetFlags() int {
+	return 0
+}
+
+// render code chunks using verbatim, or listings if we have a language
+func (options *Latex) BlockCode(out *bytes.Buffer, text []byte, info string) {
+	if info == "" {
+		out.WriteString("\n\\begin{verbatim}\n")
+	} else {
+		lang := strings.Fields(info)[0]
+		out.WriteString("\n\\begin{lstlisting}[language=")
+		out.WriteString(lang)
+		out.WriteString("]\n")
+	}
+	out.Write(text)
+	if info == "" {
+		out.WriteString("\n\\end{verbatim}\n")
+	} else {
+		out.WriteString("\n\\end{lstlisting}\n")
+	}
+}
+
+func (options *Latex) TitleBlock(out *bytes.Buffer, text []byte) {
+
+}
+
+func (options *Latex) BlockQuote(out *bytes.Buffer, text []byte) {
+	out.WriteString("\n\\begin{quotation}\n")
+	out.Write(text)
+	out.WriteString("\n\\end{quotation}\n")
+}
+
+func (options *Latex) BlockHtml(out *bytes.Buffer, text []byte) {
+	// a pretty lame thing to do...
+	out.WriteString("\n\\begin{verbatim}\n")
+	out.Write(text)
+	out.WriteString("\n\\end{verbatim}\n")
+}
+
+func (options *Latex) Header(out *bytes.Buffer, text func() bool, level int, id string) {
+	marker := out.Len()
+
+	switch level {
+	case 1:
+		out.WriteString("\n\\section{")
+	case 2:
+		out.WriteString("\n\\subsection{")
+	case 3:
+		out.WriteString("\n\\subsubsection{")
+	case 4:
+		out.WriteString("\n\\paragraph{")
+	case 5:
+		out.WriteString("\n\\subparagraph{")
+	case 6:
+		out.WriteString("\n\\textbf{")
+	}
+	if !text() {
+		out.Truncate(marker)
+		return
+	}
+	out.WriteString("}\n")
+}
+
+func (options *Latex) HRule(out *bytes.Buffer) {
+	out.WriteString("\n\\HRule\n")
+}
+
+func (options *Latex) List(out *bytes.Buffer, text func() bool, flags int) {
+	marker := out.Len()
+	if flags&LIST_TYPE_ORDERED != 0 {
+		out.WriteString("\n\\begin{enumerate}\n")
+	} else {
+		out.WriteString("\n\\begin{itemize}\n")
+	}
+	if !text() {
+		out.Truncate(marker)
+		return
+	}
+	if flags&LIST_TYPE_ORDERED != 0 {
+		out.WriteString("\n\\end{enumerate}\n")
+	} else {
+		out.WriteString("\n\\end{itemize}\n")
+	}
+}
+
+func (options *Latex) ListItem(out *bytes.Buffer, text []byte, flags int) {
+	out.WriteString("\n\\item ")
+	out.Write(text)
+}
+
+func (options *Latex) Paragraph(out *bytes.Buffer, text func() bool) {
+	marker := out.Len()
+	out.WriteString("\n")
+	if !text() {
+		out.Truncate(marker)
+		return
+	}
+	out.WriteString("\n")
+}
+
+func (options *Latex) Table(out *bytes.Buffer, header []byte, body []byte, columnData []int) {
+	out.WriteString("\n\\begin{tabular}{")
+	for _, elt := range columnData {
+		switch elt {
+		case TABLE_ALIGNMENT_LEFT:
+			out.WriteByte('l')
+		case TABLE_ALIGNMENT_RIGHT:
+			out.WriteByte('r')
+		default:
+			out.WriteByte('c')
+		}
+	}
+	out.WriteString("}\n")
+	out.Write(header)
+	out.WriteString(" \\\\\n\\hline\n")
+	out.Write(body)
+	out.WriteString("\n\\end{tabular}\n")
+}
+
+func (options *Latex) TableRow(out *bytes.Buffer, text []byte) {
+	if out.Len() > 0 {
+		out.WriteString(" \\\\\n")
+	}
+	out.Write(text)
+}
+
+func (options *Latex) TableHeaderCell(out *bytes.Buffer, text []byte, align int) {
+	if out.Len() > 0 {
+		out.WriteString(" & ")
+	}
+	out.Write(text)
+}
+
+func (options *Latex) TableCell(out *bytes.Buffer, text []byte, align int) {
+	if out.Len() > 0 {
+		out.WriteString(" & ")
+	}
+	out.Write(text)
+}
+
+// TODO: this
+func (options *Latex) Footnotes(out *bytes.Buffer, text func() bool) {
+
+}
+
+func (options *Latex) FootnoteItem(out *bytes.Buffer, name, text []byte, flags int) {
+
+}
+
+func (options *Latex) AutoLink(out *bytes.Buffer, link []byte, kind int) {
+	out.WriteString("\\href{")
+	if kind == LINK_TYPE_EMAIL {
+		out.WriteString("mailto:")
+	}
+	out.Write(link)
+	out.WriteString("}{")
+	out.Write(link)
+	out.WriteString("}")
+}
+
+func (options *Latex) CodeSpan(out *bytes.Buffer, text []byte) {
+	out.WriteString("\\texttt{")
+	escapeSpecialChars(out, text)
+	out.WriteString("}")
+}
+
+func (options *Latex) DoubleEmphasis(out *bytes.Buffer, text []byte) {
+	out.WriteString("\\textbf{")
+	out.Write(text)
+	out.WriteString("}")
+}
+
+func (options *Latex) Emphasis(out *bytes.Buffer, text []byte) {
+	out.WriteString("\\textit{")
+	out.Write(text)
+	out.WriteString("}")
+}
+
+func (options *Latex) Image(out *bytes.Buffer, link []byte, title []byte, alt []byte) {
+	if bytes.HasPrefix(link, []byte("http://")) || bytes.HasPrefix(link, []byte("https://")) {
+		// treat it like a link
+		out.WriteString("\\href{")
+		out.Write(link)
+		out.WriteString("}{")
+		out.Write(alt)
+		out.WriteString("}")
+	} else {
+		out.WriteString("\\includegraphics{")
+		out.Write(link)
+		out.WriteString("}")
+	}
+}
+
+func (options *Latex) LineBreak(out *bytes.Buffer) {
+	out.WriteString(" \\\\\n")
+}
+
+func (options *Latex) Link(out *bytes.Buffer, link []byte, title []byte, content []byte) {
+	out.WriteString("\\href{")
+	out.Write(link)
+	out.WriteString("}{")
+	out.Write(content)
+	out.WriteString("}")
+}
+
+func (options *Latex) RawHtmlTag(out *bytes.Buffer, tag []byte) {
+}
+
+func (options *Latex) TripleEmphasis(out *bytes.Buffer, text []byte) {
+	out.WriteString("\\textbf{\\textit{")
+	out.Write(text)
+	out.WriteString("}}")
+}
+
+func (options *Latex) StrikeThrough(out *bytes.Buffer, text []byte) {
+	out.WriteString("\\sout{")
+	out.Write(text)
+	out.WriteString("}")
+}
+
+// TODO: this
+func (options *Latex) FootnoteRef(out *bytes.Buffer, ref []byte, id int) {
+
+}
+
+func needsBackslash(c byte) bool {
+	for _, r := range []byte("_{}%$&\\~#") {
+		if c == r {
+			return true
+		}
+	}
+	return false
+}
+
+func escapeSpecialChars(out *bytes.Buffer, text []byte) {
+	for i := 0; i < len(text); i++ {
+		// directly copy normal characters
+		org := i
+
+		for i < len(text) && !needsBackslash(text[i]) {
+			i++
+		}
+		if i > org {
+			out.Write(text[org:i])
+		}
+
+		// escape a character
+		if i >= len(text) {
+			break
+		}
+		out.WriteByte('\\')
+		out.WriteByte(text[i])
+	}
+}
+
+func (options *Latex) Entity(out *bytes.Buffer, entity []byte) {
+	// TODO: convert this into a unicode character or something
+	out.Write(entity)
+}
+
+func (options *Latex) NormalText(out *bytes.Buffer, text []byte) {
+	escapeSpecialChars(out, text)
+}
+
+// header and footer
+func (options *Latex) DocumentHeader(out *bytes.Buffer) {
+	out.WriteString("\\documentclass{article}\n")
+	out.WriteString("\n")
+	out.WriteString("\\usepackage{graphicx}\n")
+	out.WriteString("\\usepackage{listings}\n")
+	out.WriteString("\\usepackage[margin=1in]{geometry}\n")
+	out.WriteString("\\usepackage[utf8]{inputenc}\n")
+	out.WriteString("\\usepackage{verbatim}\n")
+	out.WriteString("\\usepackage[normalem]{ulem}\n")
+	out.WriteString("\\usepackage{hyperref}\n")
+	out.WriteString("\n")
+	out.WriteString("\\hypersetup{colorlinks,%\n")
+	out.WriteString("  citecolor=black,%\n")
+	out.WriteString("  filecolor=black,%\n")
+	out.WriteString("  linkcolor=black,%\n")
+	out.WriteString("  urlcolor=black,%\n")
+	out.WriteString("  pdfstartview=FitH,%\n")
+	out.WriteString("  breaklinks=true,%\n")
+	out.WriteString("  pdfauthor={Blackfriday Markdown Processor v")
+	out.WriteString(VERSION)
+	out.WriteString("}}\n")
+	out.WriteString("\n")
+	out.WriteString("\\newcommand{\\HRule}{\\rule{\\linewidth}{0.5mm}}\n")
+	out.WriteString("\\addtolength{\\parskip}{0.5\\baselineskip}\n")
+	out.WriteString("\\parindent=0pt\n")
+	out.WriteString("\n")
+	out.WriteString("\\begin{document}\n")
+}
+
+func (options *Latex) DocumentFooter(out *bytes.Buffer) {
+	out.WriteString("\n\\end{document}\n")
+}