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3d2d158b9d
This allows having links from one slide to another one in the same presentation. Also it is needed in the new tour to cross reference lessons. R=r CC=golang-codereviews https://golang.org/cl/46130043
95 lines
2.3 KiB
Go
95 lines
2.3 KiB
Go
// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package present
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import (
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"fmt"
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"net/url"
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"strings"
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)
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func init() {
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Register("link", parseLink)
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}
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type Link struct {
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URL *url.URL
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Label string
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}
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func (l Link) TemplateName() string { return "link" }
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func parseLink(ctx *Context, fileName string, lineno int, text string) (Elem, error) {
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args := strings.Fields(text)
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url, err := url.Parse(args[1])
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if err != nil {
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return nil, err
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}
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label := ""
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if len(args) > 2 {
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label = strings.Join(args[2:], " ")
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} else {
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scheme := url.Scheme + "://"
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if url.Scheme == "mailto" {
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scheme = "mailto:"
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}
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label = strings.Replace(url.String(), scheme, "", 1)
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}
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return Link{url, label}, nil
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}
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func renderLink(url, text string) string {
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text = font(text)
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if text == "" {
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text = url
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}
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// Open links in new window only when their url is absolute.
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target := "_blank"
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if url[0] == '/' {
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target = "_self"
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}
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return fmt.Sprintf(`<a href="%s" target="%s">%s</a>`, url, target, text)
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}
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// parseInlineLink parses an inline link at the start of s, and returns
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// a rendered HTML link and the total length of the raw inline link.
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// If no inline link is present, it returns all zeroes.
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func parseInlineLink(s string) (link string, length int) {
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if !strings.HasPrefix(s, "[[") {
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return
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}
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end := strings.Index(s, "]]")
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if end == -1 {
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return
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}
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urlEnd := strings.Index(s, "]")
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rawURL := s[2:urlEnd]
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const badURLChars = `<>"{}|\^[] ` + "`" // per RFC2396 section 2.4.3
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if strings.ContainsAny(rawURL, badURLChars) {
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return
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}
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if urlEnd == end {
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simpleUrl := ""
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url, err := url.Parse(rawURL)
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if err == nil {
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// If the URL is http://foo.com, drop the http://
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// In other words, render [[http://golang.org]] as:
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// <a href="http://golang.org">golang.org</a>
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if strings.HasPrefix(rawURL, url.Scheme+"://") {
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simpleUrl = strings.TrimPrefix(rawURL, url.Scheme+"://")
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} else if strings.HasPrefix(rawURL, url.Scheme+":") {
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simpleUrl = strings.TrimPrefix(rawURL, url.Scheme+":")
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}
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}
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return renderLink(rawURL, simpleUrl), end + 2
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}
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if s[urlEnd:urlEnd+2] != "][" {
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return
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}
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text := s[urlEnd+2 : end]
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return renderLink(rawURL, text), end + 2
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}
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