Update markdown parsing library to github.com/gomarkdown/markdown (#944)

vendor/github.com/gomarkdown/markdown/ast/print.go

@@ -0,0 +1,165 @@
+package ast
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"strings"
+)
+
+// Print is for debugging. It prints a string representation of parsed
+// markdown doc (result of parser.Parse()) to dst.
+//
+// To make output readable, it shortens text output.
+func Print(dst io.Writer, doc Node) {
+	PrintWithPrefix(dst, doc, "  ")
+}
+
+// PrintWithPrefix is like Print but allows customizing prefix used for
+// indentation. By default it's 2 spaces. You can change it to e.g. tab
+// by passing "\t"
+func PrintWithPrefix(w io.Writer, doc Node, prefix string) {
+	// for more compact output, don't print outer Document
+	if _, ok := doc.(*Document); ok {
+		for _, c := range doc.GetChildren() {
+			printRecur(w, c, prefix, 0)
+		}
+	} else {
+		printRecur(w, doc, prefix, 0)
+	}
+}
+
+// ToString is like Dump but returns result as a string
+func ToString(doc Node) string {
+	var buf bytes.Buffer
+	Print(&buf, doc)
+	return buf.String()
+}
+
+func contentToString(d1 []byte, d2 []byte) string {
+	if d1 != nil {
+		return string(d1)
+	}
+	if d2 != nil {
+		return string(d2)
+	}
+	return ""
+}
+
+func getContent(node Node) string {
+	if c := node.AsContainer(); c != nil {
+		return contentToString(c.Literal, c.Content)
+	}
+	leaf := node.AsLeaf()
+	return contentToString(leaf.Literal, leaf.Content)
+}
+
+func shortenString(s string, maxLen int) string {
+	// for cleaner, one-line ouput, replace some white-space chars
+	// with their escaped version
+	s = strings.Replace(s, "\n", `\n`, -1)
+	s = strings.Replace(s, "\r", `\r`, -1)
+	s = strings.Replace(s, "\t", `\t`, -1)
+	if maxLen < 0 {
+		return s
+	}
+	if len(s) < maxLen {
+		return s
+	}
+	// add "..." to indicate truncation
+	return s[:maxLen-3] + "..."
+}
+
+// get a short name of the type of v which excludes package name
+// and strips "()" from the end
+func getNodeType(node Node) string {
+	s := fmt.Sprintf("%T", node)
+	s = strings.TrimSuffix(s, "()")
+	if idx := strings.Index(s, "."); idx != -1 {
+		return s[idx+1:]
+	}
+	return s
+}
+
+func printDefault(w io.Writer, indent string, typeName string, content string) {
+	content = strings.TrimSpace(content)
+	if len(content) > 0 {
+		fmt.Fprintf(w, "%s%s '%s'\n", indent, typeName, content)
+	} else {
+		fmt.Fprintf(w, "%s%s\n", indent, typeName)
+	}
+}
+
+func getListFlags(f ListType) string {
+	var s string
+	if f&ListTypeOrdered != 0 {
+		s += "ordered "
+	}
+	if f&ListTypeDefinition != 0 {
+		s += "definition "
+	}
+	if f&ListTypeTerm != 0 {
+		s += "term "
+	}
+	if f&ListItemContainsBlock != 0 {
+		s += "has_block "
+	}
+	if f&ListItemBeginningOfList != 0 {
+		s += "start "
+	}
+	if f&ListItemEndOfList != 0 {
+		s += "end "
+	}
+	s = strings.TrimSpace(s)
+	return s
+}
+
+func printRecur(w io.Writer, node Node, prefix string, depth int) {
+	if node == nil {
+		return
+	}
+	indent := strings.Repeat(prefix, depth)
+
+	content := shortenString(getContent(node), 40)
+	typeName := getNodeType(node)
+	switch v := node.(type) {
+	case *Link:
+		content := "url=" + string(v.Destination)
+		printDefault(w, indent, typeName, content)
+	case *Image:
+		content := "url=" + string(v.Destination)
+		printDefault(w, indent, typeName, content)
+	case *List:
+		if v.Start > 1 {
+			content += fmt.Sprintf("start=%d ", v.Start)
+		}
+		if v.Tight {
+			content += "tight "
+		}
+		if v.IsFootnotesList {
+			content += "footnotes "
+		}
+		flags := getListFlags(v.ListFlags)
+		if len(flags) > 0 {
+			content += "flags=" + flags + " "
+		}
+		printDefault(w, indent, typeName, content)
+	case *ListItem:
+		if v.Tight {
+			content += "tight "
+		}
+		if v.IsFootnotesList {
+			content += "footnotes "
+		}
+		flags := getListFlags(v.ListFlags)
+		if len(flags) > 0 {
+			content += "flags=" + flags + " "
+		}
+		printDefault(w, indent, typeName, content)
+	default:
+		printDefault(w, indent, typeName, content)
+	}
+	for _, child := range node.GetChildren() {
+		printRecur(w, child, prefix, depth+1)
+	}
+}