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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package present
import (
"fmt"
"log"
"net/url"
"strings"
)
func init() {
Register("link", parseLink)
}
type Link struct {
URL *url.URL
Label string
}
func (l Link) TemplateName() string { return "link" }
func parseLink(ctx *Context, fileName string, lineno int, text string) (Elem, error) {
args := strings.Fields(text)
if len(args) < 2 {
return nil, fmt.Errorf("link element must have at least 2 arguments")
}
url, err := url.Parse(args[1])
if err != nil {
return nil, err
}
label := ""
if len(args) > 2 {
label = strings.Join(args[2:], " ")
} else {
scheme := url.Scheme + "://"
if url.Scheme == "mailto" {
scheme = "mailto:"
}
label = strings.Replace(url.String(), scheme, "", 1)
}
return Link{url, label}, nil
}
func renderLink(href, text string) string {
text = font(text)
if text == "" {
text = href
}
// Open links in new window only when their url is absolute.
target := "_blank"
if u, err := url.Parse(href); err != nil {
log.Println("renderLink parsing url:", err)
} else if !u.IsAbs() || u.Scheme == "javascript" {
target = "_self"
}
return fmt.Sprintf(`<a href="%s" target="%s">%s</a>`, href, target, text)
}
// parseInlineLink parses an inline link at the start of s, and returns
// a rendered HTML link and the total length of the raw inline link.
// If no inline link is present, it returns all zeroes.
func parseInlineLink(s string) (link string, length int) {
if !strings.HasPrefix(s, "[[") {
return
}
end := strings.Index(s, "]]")
if end == -1 {
return
}
urlEnd := strings.Index(s, "]")
rawURL := s[2:urlEnd]
const badURLChars = `<>"{}|\^[] ` + "`" // per RFC2396 section 2.4.3
if strings.ContainsAny(rawURL, badURLChars) {
return
}
if urlEnd == end {
simpleUrl := ""
url, err := url.Parse(rawURL)
if err == nil {
// If the URL is http://foo.com, drop the http://
// In other words, render [[http://golang.org]] as:
// <a href="http://golang.org">golang.org</a>
if strings.HasPrefix(rawURL, url.Scheme+"://") {
simpleUrl = strings.TrimPrefix(rawURL, url.Scheme+"://")
} else if strings.HasPrefix(rawURL, url.Scheme+":") {
simpleUrl = strings.TrimPrefix(rawURL, url.Scheme+":")
}
}
return renderLink(rawURL, simpleUrl), end + 2
}
if s[urlEnd:urlEnd+2] != "][" {
return
}
text := s[urlEnd+2 : end]
return renderLink(rawURL, text), end + 2
}