1 files changed, 312 insertions, 0 deletions
diff --git a/vendor/github.com/mattermost/html2text/html2text.go b/vendor/github.com/mattermost/html2text/html2text.go
new file mode 100644
index 000000000..61774e8a0
--- /dev/null
+++ b/vendor/github.com/mattermost/html2text/html2text.go
@@ -0,0 +1,312 @@
+package html2text
+
+import (
+	"bytes"
+	"io"
+	"io/ioutil"
+	"regexp"
+	"strings"
+	"unicode"
+
+	"github.com/dimchansky/utfbom"
+
+	"golang.org/x/net/html"
+	"golang.org/x/net/html/atom"
+)
+
+var (
+	spacingRe = regexp.MustCompile(`[ \r\n\t]+`)
+	newlineRe = regexp.MustCompile(`\n\n+`)
+)
+
+type textifyTraverseCtx struct {
+	Buf bytes.Buffer
+
+	prefix          string
+	blockquoteLevel int
+	lineLength      int
+	endsWithSpace   bool
+	endsWithNewline bool
+	justClosedDiv   bool
+}
+
+func (ctx *textifyTraverseCtx) traverse(node *html.Node) error {
+	switch node.Type {
+	default:
+		return ctx.traverseChildren(node)
+
+	case html.TextNode:
+		data := strings.Trim(spacingRe.ReplaceAllString(node.Data, " "), " ")
+		return ctx.emit(data)
+
+	case html.ElementNode:
+		return ctx.handleElementNode(node)
+	}
+}
+
+func (ctx *textifyTraverseCtx) handleElementNode(node *html.Node) error {
+	ctx.justClosedDiv = false
+	switch node.DataAtom {
+	case atom.Br:
+		return ctx.emit("\n")
+
+	case atom.H1, atom.H2, atom.H3:
+		subCtx := textifyTraverseCtx{}
+		if err := subCtx.traverseChildren(node); err != nil {
+			return err
+		}
+
+		str := subCtx.Buf.String()
+		dividerLen := 0
+		for _, line := range strings.Split(str, "\n") {
+			if lineLen := len([]rune(line)); lineLen-1 > dividerLen {
+				dividerLen = lineLen - 1
+			}
+		}
+		divider := ""
+		if node.DataAtom == atom.H1 {
+			divider = strings.Repeat("*", dividerLen)
+		} else {
+			divider = strings.Repeat("-", dividerLen)
+		}
+
+		if node.DataAtom == atom.H3 {
+			return ctx.emit("\n\n" + str + "\n" + divider + "\n\n")
+		}
+		return ctx.emit("\n\n" + divider + "\n" + str + "\n" + divider + "\n\n")
+
+	case atom.Blockquote:
+		ctx.blockquoteLevel++
+		ctx.prefix = strings.Repeat(">", ctx.blockquoteLevel) + " "
+		if err := ctx.emit("\n"); err != nil {
+			return err
+		}
+		if ctx.blockquoteLevel == 1 {
+			if err := ctx.emit("\n"); err != nil {
+				return err
+			}
+		}
+		if err := ctx.traverseChildren(node); err != nil {
+			return err
+		}
+		ctx.blockquoteLevel--
+		ctx.prefix = strings.Repeat(">", ctx.blockquoteLevel)
+		if ctx.blockquoteLevel > 0 {
+			ctx.prefix += " "
+		}
+		return ctx.emit("\n\n")
+
+	case atom.Div:
+		if ctx.lineLength > 0 {
+			if err := ctx.emit("\n"); err != nil {
+				return err
+			}
+		}
+		if err := ctx.traverseChildren(node); err != nil {
+			return err
+		}
+		var err error
+		if ctx.justClosedDiv == false {
+			err = ctx.emit("\n")
+		}
+		ctx.justClosedDiv = true
+		return err
+
+	case atom.Li:
+		if err := ctx.emit("* "); err != nil {
+			return err
+		}
+
+		if err := ctx.traverseChildren(node); err != nil {
+			return err
+		}
+
+		return ctx.emit("\n")
+
+	case atom.B, atom.Strong:
+		subCtx := textifyTraverseCtx{}
+		subCtx.endsWithSpace = true
+		if err := subCtx.traverseChildren(node); err != nil {
+			return err
+		}
+		str := subCtx.Buf.String()
+		return ctx.emit("*" + str + "*")
+
+	case atom.A:
+		// If image is the only child, take its alt text as the link text
+		if img := node.FirstChild; img != nil && node.LastChild == img && img.DataAtom == atom.Img {
+			if altText := getAttrVal(img, "alt"); altText != "" {
+				ctx.emit(altText)
+			}
+		} else if err := ctx.traverseChildren(node); err != nil {
+			return err
+		}
+
+		hrefLink := ""
+		if attrVal := getAttrVal(node, "href"); attrVal != "" {
+			attrVal = ctx.normalizeHrefLink(attrVal)
+			if attrVal != "" {
+				hrefLink = "( " + attrVal + " )"
+			}
+		}
+
+		return ctx.emit(hrefLink)
+
+	case atom.P, atom.Ul, atom.Table:
+		if err := ctx.emit("\n\n"); err != nil {
+			return err
+		}
+
+		if err := ctx.traverseChildren(node); err != nil {
+			return err
+		}
+
+		return ctx.emit("\n\n")
+
+	case atom.Tr:
+		if err := ctx.traverseChildren(node); err != nil {
+			return err
+		}
+
+		return ctx.emit("\n")
+
+	case atom.Style, atom.Script, atom.Head:
+		// Ignore the subtree
+		return nil
+
+	default:
+		return ctx.traverseChildren(node)
+	}
+}
+func (ctx *textifyTraverseCtx) traverseChildren(node *html.Node) error {
+	for c := node.FirstChild; c != nil; c = c.NextSibling {
+		if err := ctx.traverse(c); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (ctx *textifyTraverseCtx) emit(data string) error {
+	if len(data) == 0 {
+		return nil
+	}
+	lines := ctx.breakLongLines(data)
+	var err error
+	for _, line := range lines {
+		runes := []rune(line)
+		startsWithSpace := unicode.IsSpace(runes[0])
+		if !startsWithSpace && !ctx.endsWithSpace {
+			ctx.Buf.WriteByte(' ')
+			ctx.lineLength++
+		}
+		ctx.endsWithSpace = unicode.IsSpace(runes[len(runes)-1])
+		for _, c := range line {
+			_, err = ctx.Buf.WriteString(string(c))
+			if err != nil {
+				return err
+			}
+			ctx.lineLength++
+			if c == '\n' {
+				ctx.lineLength = 0
+				if ctx.prefix != "" {
+					_, err = ctx.Buf.WriteString(ctx.prefix)
+					if err != nil {
+						return err
+					}
+				}
+			}
+		}
+	}
+	return nil
+}
+
+func (ctx *textifyTraverseCtx) breakLongLines(data string) []string {
+	// only break lines when we are in blockquotes
+	if ctx.blockquoteLevel == 0 {
+		return []string{data}
+	}
+	var ret []string
+	runes := []rune(data)
+	l := len(runes)
+	existing := ctx.lineLength
+	if existing >= 74 {
+		ret = append(ret, "\n")
+		existing = 0
+	}
+	for l+existing > 74 {
+		i := 74 - existing
+		for i >= 0 && !unicode.IsSpace(runes[i]) {
+			i--
+		}
+		if i == -1 {
+			// no spaces, so go the other way
+			i = 74 - existing
+			for i < l && !unicode.IsSpace(runes[i]) {
+				i++
+			}
+		}
+		ret = append(ret, string(runes[:i])+"\n")
+		for i < l && unicode.IsSpace(runes[i]) {
+			i++
+		}
+		runes = runes[i:]
+		l = len(runes)
+		existing = 0
+	}
+	if len(runes) > 0 {
+		ret = append(ret, string(runes))
+	}
+	return ret
+}
+
+func (ctx *textifyTraverseCtx) normalizeHrefLink(link string) string {
+	link = strings.TrimSpace(link)
+	link = strings.TrimPrefix(link, "mailto:")
+	return link
+}
+
+func getAttrVal(node *html.Node, attrName string) string {
+	for _, attr := range node.Attr {
+		if attr.Key == attrName {
+			return attr.Val
+		}
+	}
+
+	return ""
+}
+
+func FromHtmlNode(doc *html.Node) (string, error) {
+	ctx := textifyTraverseCtx{
+		Buf: bytes.Buffer{},
+	}
+	if err := ctx.traverse(doc); err != nil {
+		return "", err
+	}
+
+	text := strings.TrimSpace(newlineRe.ReplaceAllString(
+		strings.Replace(ctx.Buf.String(), "\n ", "\n", -1), "\n\n"))
+	return text, nil
+
+}
+
+func FromReader(reader io.Reader) (string, error) {
+	bs, err := ioutil.ReadAll(reader)
+	newReader, _ := utfbom.Skip(bytes.NewReader(bs))
+
+	doc, err := html.Parse(newReader)
+	if err != nil {
+		return "", err
+	}
+	return FromHtmlNode(doc)
+}
+
+func FromString(input string) (string, error) {
+	bs := utfbom.SkipOnly(bytes.NewReader([]byte(input)))
+	text, err := FromReader(bs)
+	if err != nil {
+		return "", err
+	}
+	return text, nil
+}