improve method PlainText.

node.go

@@ -81,17 +81,6 @@ func (n *Node) AllText(pat ...string) *string {
 	return nil
 }
 
-func (n *Node) PlainText() string {
-	if n == nil {
-		return ""
-	}
-	var buf bytes.Buffer
-	for _, s := range n.Descendants(TextNode).Strings(GetText) {
-		buf.WriteString(s)
-	}
-	return buf.String()
-}
-
 func (n *Node) Render() *string {
 	if n == nil {
 		return nil

plain.go

@@ -0,0 +1,108 @@
+// Copyright 2005, Hǎiliàng Wáng. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package query
+
+import (
+	"bytes"
+	"strings"
+
+	"golang.org/x/net/html"
+	"h12.me/html-query/expr"
+)
+
+func (n *Node) PlainText() *string {
+	if n == nil {
+		return nil
+	}
+	var w bytes.Buffer
+	if err := renderPlain(&w, &n.n); err != nil {
+		return nil
+	}
+	s := strings.TrimSpace(w.String())
+	return &s
+}
+
+func renderPlain(w writer, n *html.Node) error {
+	switch n.Type {
+	case html.TextNode:
+		w.WriteString(n.Data)
+	case html.DocumentNode:
+		for c := n.FirstChild; c != nil; c = c.NextSibling {
+			if err := renderPlain(w, c); err != nil {
+				return err
+			}
+		}
+		return nil
+	case html.ElementNode:
+		return renderPlainElementNode(w, n)
+	}
+	return nil
+}
+
+func renderPlainElementNode(w writer, n *html.Node) error {
+	if c := n.FirstChild; c != nil && c.Type == html.TextNode && strings.HasPrefix(c.Data, "\n") {
+		switch n.Data {
+		case "pre", "listing", "textarea":
+			if err := w.WriteByte('\n'); err != nil {
+				return err
+			}
+		}
+	}
+
+	switch n.Data {
+	case "iframe", "noembed", "noframes", "noscript", "plaintext", "script", "style", "xmp":
+		for c := n.FirstChild; c != nil; c = c.NextSibling {
+			if c.Type == html.TextNode {
+				if _, err := w.WriteString(c.Data); err != nil {
+					return err
+				}
+			} else {
+				if err := renderPlain(w, c); err != nil {
+					return err
+				}
+			}
+		}
+		if n.Data == "plaintext" {
+			return plaintextAbort
+		}
+		return nil
+	case "a":
+		if isURL(n.FirstChild.Data) {
+			renderPlainChild(w, n)
+		} else if url := expr.GetAttr(n, "href"); url != nil && *url != "" {
+			w.WriteString("[")
+			renderPlainChild(w, n)
+			w.WriteString("](")
+			w.WriteString(*url)
+			w.WriteString(")")
+		} else {
+			renderPlainChild(w, n)
+		}
+		return nil
+	}
+
+	renderPlainChild(w, n)
+	// write break after children are written
+	switch n.Data {
+	case "p", "br":
+		writeBreak(w)
+	}
+	return nil
+}
+
+func isURL(s string) bool {
+	s = strings.TrimSpace(s)
+	return strings.Contains(s, "http://") ||
+		strings.Contains(s, "@")
+}
+
+func renderPlainChild(w writer, n *html.Node) error {
+	for c := n.FirstChild; c != nil; c = c.NextSibling {
+		if err := renderPlain(w, c); err != nil {
+			return err
+		}
+	}
+	return nil
+}