github.com/jgarto/itcv@v0.0.0-20180826224514-4eea09c1aa0d/_vendor/src/golang.org/x/tools/present/link.go (about)

     1  // Copyright 2012 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package present
     6  
     7  import (
     8  	"fmt"
     9  	"log"
    10  	"net/url"
    11  	"strings"
    12  )
    13  
    14  func init() {
    15  	Register("link", parseLink)
    16  }
    17  
    18  type Link struct {
    19  	URL   *url.URL
    20  	Label string
    21  }
    22  
    23  func (l Link) TemplateName() string { return "link" }
    24  
    25  func parseLink(ctx *Context, fileName string, lineno int, text string) (Elem, error) {
    26  	args := strings.Fields(text)
    27  	if len(args) < 2 {
    28  		return nil, fmt.Errorf("link element must have at least 2 arguments")
    29  	}
    30  	url, err := url.Parse(args[1])
    31  	if err != nil {
    32  		return nil, err
    33  	}
    34  	label := ""
    35  	if len(args) > 2 {
    36  		label = strings.Join(args[2:], " ")
    37  	} else {
    38  		scheme := url.Scheme + "://"
    39  		if url.Scheme == "mailto" {
    40  			scheme = "mailto:"
    41  		}
    42  		label = strings.Replace(url.String(), scheme, "", 1)
    43  	}
    44  	return Link{url, label}, nil
    45  }
    46  
    47  func renderLink(href, text string) string {
    48  	text = font(text)
    49  	if text == "" {
    50  		text = href
    51  	}
    52  	// Open links in new window only when their url is absolute.
    53  	target := "_blank"
    54  	if u, err := url.Parse(href); err != nil {
    55  		log.Println("renderLink parsing url:", err)
    56  	} else if !u.IsAbs() || u.Scheme == "javascript" {
    57  		target = "_self"
    58  	}
    59  
    60  	return fmt.Sprintf(`<a href="%s" target="%s">%s</a>`, href, target, text)
    61  }
    62  
    63  // parseInlineLink parses an inline link at the start of s, and returns
    64  // a rendered HTML link and the total length of the raw inline link.
    65  // If no inline link is present, it returns all zeroes.
    66  func parseInlineLink(s string) (link string, length int) {
    67  	if !strings.HasPrefix(s, "[[") {
    68  		return
    69  	}
    70  	end := strings.Index(s, "]]")
    71  	if end == -1 {
    72  		return
    73  	}
    74  	urlEnd := strings.Index(s, "]")
    75  	rawURL := s[2:urlEnd]
    76  	const badURLChars = `<>"{}|\^[] ` + "`" // per RFC2396 section 2.4.3
    77  	if strings.ContainsAny(rawURL, badURLChars) {
    78  		return
    79  	}
    80  	if urlEnd == end {
    81  		simpleUrl := ""
    82  		url, err := url.Parse(rawURL)
    83  		if err == nil {
    84  			// If the URL is http://foo.com, drop the http://
    85  			// In other words, render [[http://golang.org]] as:
    86  			//   <a href="http://golang.org">golang.org</a>
    87  			if strings.HasPrefix(rawURL, url.Scheme+"://") {
    88  				simpleUrl = strings.TrimPrefix(rawURL, url.Scheme+"://")
    89  			} else if strings.HasPrefix(rawURL, url.Scheme+":") {
    90  				simpleUrl = strings.TrimPrefix(rawURL, url.Scheme+":")
    91  			}
    92  		}
    93  		return renderLink(rawURL, simpleUrl), end + 2
    94  	}
    95  	if s[urlEnd:urlEnd+2] != "][" {
    96  		return
    97  	}
    98  	text := s[urlEnd+2 : end]
    99  	return renderLink(rawURL, text), end + 2
   100  }