/usr/share/gocode/src/github.com/tent/http-link-go/link.go is in golang-github-tent-http-link-go-dev 0.0~git20130702.0.ac974c6-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 | // Package link implements parsing and serialization of Link header values as
// defined in RFC 5988.
package link
import (
"bytes"
"errors"
"sort"
"unicode"
)
type Link struct {
URI string
Rel string
Params map[string]string
}
// Format serializes a slice of Links into a header value. It does not currently
// implement RFC 2231 handling of non-ASCII character encoding and language
// information.
func Format(links []Link) string {
buf := &bytes.Buffer{}
for i, link := range links {
if i > 0 {
buf.Write([]byte(", "))
}
buf.WriteByte('<')
buf.WriteString(link.URI)
buf.WriteByte('>')
writeParam(buf, "rel", link.Rel)
keys := make([]string, 0, len(link.Params))
for k := range link.Params {
keys = append(keys, k)
}
sort.Strings(keys)
for _, k := range keys {
writeParam(buf, k, link.Params[k])
}
}
return buf.String()
}
func writeParam(buf *bytes.Buffer, key, value string) {
buf.Write([]byte("; "))
buf.WriteString(key)
buf.Write([]byte(`="`))
buf.WriteString(value)
buf.WriteByte('"')
}
// Parse parses a Link header value into a slice of Links. It does not currently
// implement RFC 2231 handling of non-ASCII character encoding and language
// information.
func Parse(l string) ([]Link, error) {
v := []byte(l)
v = bytes.TrimSpace(v)
if len(v) == 0 {
return nil, nil
}
links := make([]Link, 0, 1)
for len(v) > 0 {
if v[0] != '<' {
return nil, errors.New("link: does not start with <")
}
lend := bytes.IndexByte(v, '>')
if lend == -1 {
return nil, errors.New("link: does not contain ending >")
}
params := make(map[string]string)
link := Link{URI: string(v[1:lend]), Params: params}
links = append(links, link)
// trim off parsed url
v = v[lend+1:]
if len(v) == 0 {
break
}
v = bytes.TrimLeftFunc(v, unicode.IsSpace)
for len(v) > 0 {
if v[0] != ';' && v[0] != ',' {
return nil, errors.New(`link: expected ";" or "'", got "` + string(v[0:1]) + `"`)
}
var next bool
if v[0] == ',' {
next = true
}
v = bytes.TrimLeftFunc(v[1:], unicode.IsSpace)
if next || len(v) == 0 {
break
}
var key, value []byte
key, value, v = consumeParam(v)
if key == nil || value == nil {
return nil, errors.New("link: malformed param")
}
if k := string(key); k == "rel" {
if links[len(links)-1].Rel == "" {
links[len(links)-1].Rel = string(value)
}
} else {
params[k] = string(value)
}
v = bytes.TrimLeftFunc(v, unicode.IsSpace)
}
}
return links, nil
}
func isTokenChar(r rune) bool {
return r > 0x20 && r < 0x7f && r != '"' && r != ',' && r != '=' && r != ';'
}
func isNotTokenChar(r rune) bool { return !isTokenChar(r) }
func consumeToken(v []byte) (token, rest []byte) {
notPos := bytes.IndexFunc(v, isNotTokenChar)
if notPos == -1 {
return v, nil
}
if notPos == 0 {
return nil, v
}
return v[0:notPos], v[notPos:]
}
func consumeValue(v []byte) (value, rest []byte) {
if v[0] != '"' {
return nil, v
}
rest = v[1:]
buffer := &bytes.Buffer{}
var nextIsLiteral bool
for idx, r := range string(rest) {
switch {
case nextIsLiteral:
buffer.WriteRune(r)
nextIsLiteral = false
case r == '"':
return buffer.Bytes(), rest[idx+1:]
case r == '\\':
nextIsLiteral = true
case r != '\r' && r != '\n':
buffer.WriteRune(r)
default:
return nil, v
}
}
return nil, v
}
func consumeParam(v []byte) (param, value, rest []byte) {
param, rest = consumeToken(v)
param = bytes.ToLower(param)
if param == nil {
return nil, nil, v
}
rest = bytes.TrimLeftFunc(rest, unicode.IsSpace)
if len(rest) == 0 || rest[0] != '=' {
return nil, nil, v
}
rest = rest[1:] // consume equals sign
rest = bytes.TrimLeftFunc(rest, unicode.IsSpace)
if len(rest) == 0 {
return nil, nil, v
}
if rest[0] != '"' {
value, rest = consumeToken(rest)
} else {
value, rest = consumeValue(rest)
}
if value == nil {
return nil, nil, v
}
return param, value, rest
}
|