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// Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.
// Copyright 2016 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.
//go:build !go1.10
// Package idna implements IDNA2008 using the compatibility processing
// defined by UTS (Unicode Technical Standard) #46, which defines a standard to
// deal with the transition from IDNA2003.
//
// IDNA2008 (Internationalized Domain Names for Applications), is defined in RFC
// 5890, RFC 5891, RFC 5892, RFC 5893 and RFC 5894.
// UTS #46 is defined in https://www.unicode.org/reports/tr46.
// See https://unicode.org/cldr/utility/idna.jsp for a visualization of the
// differences between these two standards.
package idna // import "golang.org/x/net/idna"
import (
"fmt"
"strings"
"unicode/utf8"
"golang.org/x/text/secure/bidirule"
"golang.org/x/text/unicode/norm"
)
// NOTE: Unlike common practice in Go APIs, the functions will return a
// sanitized domain name in case of errors. Browsers sometimes use a partially
// evaluated string as lookup.
// TODO: the current error handling is, in my opinion, the least opinionated.
// Other strategies are also viable, though:
// Option 1) Return an empty string in case of error, but allow the user to
// specify explicitly which errors to ignore.
// Option 2) Return the partially evaluated string if it is itself a valid
// string, otherwise return the empty string in case of error.
// Option 3) Option 1 and 2.
// Option 4) Always return an empty string for now and implement Option 1 as
// needed, and document that the return string may not be empty in case of
// error in the future.
// I think Option 1 is best, but it is quite opinionated.
// ToASCII is a wrapper for Punycode.ToASCII.
func ToASCII(s string) (string, error) {
return Punycode.process(s, true)
}
// ToUnicode is a wrapper for Punycode.ToUnicode.
func ToUnicode(s string) (string, error) {
return Punycode.process(s, false)
}
// An Option configures a Profile at creation time.
type Option func(*options)
// Transitional sets a Profile to use the Transitional mapping as defined in UTS
// #46. This will cause, for example, "ß" to be mapped to "ss". Using the
// transitional mapping provides a compromise between IDNA2003 and IDNA2008
// compatibility. It is used by some browsers when resolving domain names. This
// option is only meaningful if combined with MapForLookup.
func Transitional(transitional bool) Option {
return func(o *options) { o.transitional = transitional }
}
// VerifyDNSLength sets whether a Profile should fail if any of the IDN parts
// are longer than allowed by the RFC.
//
// This option corresponds to the VerifyDnsLength flag in UTS #46.
func VerifyDNSLength(verify bool) Option {
return func(o *options) { o.verifyDNSLength = verify }
}
// RemoveLeadingDots removes leading label separators. Leading runes that map to
// dots, such as U+3002 IDEOGRAPHIC FULL STOP, are removed as well.
func RemoveLeadingDots(remove bool) Option {
return func(o *options) { o.removeLeadingDots = remove }
}
// ValidateLabels sets whether to check the mandatory label validation criteria
// as defined in Section 5.4 of RFC 5891. This includes testing for correct use
// of hyphens ('-'), normalization, validity of runes, and the context rules.
// In particular, ValidateLabels also sets the CheckHyphens and CheckJoiners flags
// in UTS #46.
func ValidateLabels(enable bool) Option {
return func(o *options) {
// Don't override existing mappings, but set one that at least checks
// normalization if it is not set.
if o.mapping == nil && enable {
o.mapping = normalize
}
o.trie = trie
o.checkJoiners = enable
o.checkHyphens = enable
if enable {
o.fromPuny = validateFromPunycode
} else {
o.fromPuny = nil
}
}
}
// CheckHyphens sets whether to check for correct use of hyphens ('-') in
// labels. Most web browsers do not have this option set, since labels such as
// "r3---sn-apo3qvuoxuxbt-j5pe" are in common use.
//
// This option corresponds to the CheckHyphens flag in UTS #46.
func CheckHyphens(enable bool) Option {
return func(o *options) { o.checkHyphens = enable }
}
// CheckJoiners sets whether to check the ContextJ rules as defined in Appendix
// A of RFC 5892, concerning the use of joiner runes.
//
// This option corresponds to the CheckJoiners flag in UTS #46.
func CheckJoiners(enable bool) Option {
return func(o *options) {
o.trie = trie
o.checkJoiners = enable
}
}
// StrictDomainName limits the set of permissible ASCII characters to those
// allowed in domain names as defined in RFC 1034 (A-Z, a-z, 0-9 and the
// hyphen). This is set by default for MapForLookup and ValidateForRegistration,
// but is only useful if ValidateLabels is set.
//
// This option is useful, for instance, for browsers that allow characters
// outside this range, for example a '_' (U+005F LOW LINE). See
// http://www.rfc-editor.org/std/std3.txt for more details.
//
// This option corresponds to the UseSTD3ASCIIRules flag in UTS #46.
func StrictDomainName(use bool) Option {
return func(o *options) { o.useSTD3Rules = use }
}
// NOTE: the following options pull in tables. The tables should not be linked
// in as long as the options are not used.
// BidiRule enables the Bidi rule as defined in RFC 5893. Any application
// that relies on proper validation of labels should include this rule.
//
// This option corresponds to the CheckBidi flag in UTS #46.
func BidiRule() Option {
return func(o *options) { o.bidirule = bidirule.ValidString }
}
// ValidateForRegistration sets validation options to verify that a given IDN is
// properly formatted for registration as defined by Section 4 of RFC 5891.
func ValidateForRegistration() Option {
return func(o *options) {
o.mapping = validateRegistration
StrictDomainName(true)(o)
ValidateLabels(true)(o)
VerifyDNSLength(true)(o)
BidiRule()(o)
}
}
// MapForLookup sets validation and mapping options such that a given IDN is
// transformed for domain name lookup according to the requirements set out in
// Section 5 of RFC 5891. The mappings follow the recommendations of RFC 5894,
// RFC 5895 and UTS 46. It does not add the Bidi Rule. Use the BidiRule option
// to add this check.
//
// The mappings include normalization and mapping case, width and other
// compatibility mappings.
func MapForLookup() Option {
return func(o *options) {
o.mapping = validateAndMap
StrictDomainName(true)(o)
ValidateLabels(true)(o)
RemoveLeadingDots(true)(o)
}
}
type options struct {
transitional bool
useSTD3Rules bool
checkHyphens bool
checkJoiners bool
verifyDNSLength bool
removeLeadingDots bool
trie *idnaTrie
// fromPuny calls validation rules when converting A-labels to U-labels.
fromPuny func(p *Profile, s string) error
// mapping implements a validation and mapping step as defined in RFC 5895
// or UTS 46, tailored to, for example, domain registration or lookup.
mapping func(p *Profile, s string) (string, error)
// bidirule, if specified, checks whether s conforms to the Bidi Rule
// defined in RFC 5893.
bidirule func(s string) bool
}
// A Profile defines the configuration of a IDNA mapper.
type Profile struct {
options
}
func apply(o *options, opts []Option) {
for _, f := range opts {
f(o)
}
}
// New creates a new Profile.
//
// With no options, the returned Profile is the most permissive and equals the
// Punycode Profile. Options can be passed to further restrict the Profile. The
// MapForLookup and ValidateForRegistration options set a collection of options,
// for lookup and registration purposes respectively, which can be tailored by
// adding more fine-grained options, where later options override earlier
// options.
func New(o ...Option) *Profile {
p := &Profile{}
apply(&p.options, o)
return p
}
// ToASCII converts a domain or domain label to its ASCII form. For example,
// ToASCII("bücher.example.com") is "xn--bcher-kva.example.com", and
// ToASCII("golang") is "golang". If an error is encountered it will return
// an error and a (partially) processed result.
func (p *Profile) ToASCII(s string) (string, error) {
return p.process(s, true)
}
// ToUnicode converts a domain or domain label to its Unicode form. For example,
// ToUnicode("xn--bcher-kva.example.com") is "bücher.example.com", and
// ToUnicode("golang") is "golang". If an error is encountered it will return
// an error and a (partially) processed result.
func (p *Profile) ToUnicode(s string) (string, error) {
pp := *p
pp.transitional = false
return pp.process(s, false)
}
// String reports a string with a description of the profile for debugging
// purposes. The string format may change with different versions.
func (p *Profile) String() string {
s := ""
if p.transitional {
s = "Transitional"
} else {
s = "NonTransitional"
}
if p.useSTD3Rules {
s += ":UseSTD3Rules"
}
if p.checkHyphens {
s += ":CheckHyphens"
}
if p.checkJoiners {
s += ":CheckJoiners"
}
if p.verifyDNSLength {
s += ":VerifyDNSLength"
}
return s
}
var (
// Punycode is a Profile that does raw punycode processing with a minimum
// of validation.
Punycode *Profile = punycode
// Lookup is the recommended profile for looking up domain names, according
// to Section 5 of RFC 5891. The exact configuration of this profile may
// change over time.
Lookup *Profile = lookup
// Display is the recommended profile for displaying domain names.
// The configuration of this profile may change over time.
Display *Profile = display
// Registration is the recommended profile for checking whether a given
// IDN is valid for registration, according to Section 4 of RFC 5891.
Registration *Profile = registration
punycode = &Profile{}
lookup = &Profile{options{
transitional: true,
removeLeadingDots: true,
useSTD3Rules: true,
checkHyphens: true,
checkJoiners: true,
trie: trie,
fromPuny: validateFromPunycode,
mapping: validateAndMap,
bidirule: bidirule.ValidString,
}}
display = &Profile{options{
useSTD3Rules: true,
removeLeadingDots: true,
checkHyphens: true,
checkJoiners: true,
trie: trie,
fromPuny: validateFromPunycode,
mapping: validateAndMap,
bidirule: bidirule.ValidString,
}}
registration = &Profile{options{
useSTD3Rules: true,
verifyDNSLength: true,
checkHyphens: true,
checkJoiners: true,
trie: trie,
fromPuny: validateFromPunycode,
mapping: validateRegistration,
bidirule: bidirule.ValidString,
}}
// TODO: profiles
// Register: recommended for approving domain names: don't do any mappings
// but rather reject on invalid input. Bundle or block deviation characters.
)
type labelError struct{ label, code_ string }
func (e labelError) code() string { return e.code_ }
func (e labelError) Error() string {
return fmt.Sprintf("idna: invalid label %q", e.label)
}
type runeError rune
func (e runeError) code() string { return "P1" }
func (e runeError) Error() string {
return fmt.Sprintf("idna: disallowed rune %U", e)
}
// process implements the algorithm described in section 4 of UTS #46,
// see https://www.unicode.org/reports/tr46.
func (p *Profile) process(s string, toASCII bool) (string, error) {
var err error
if p.mapping != nil {
s, err = p.mapping(p, s)
}
// Remove leading empty labels.
if p.removeLeadingDots {
for ; len(s) > 0 && s[0] == '.'; s = s[1:] {
}
}
// It seems like we should only create this error on ToASCII, but the
// UTS 46 conformance tests suggests we should always check this.
if err == nil && p.verifyDNSLength && s == "" {
err = &labelError{s, "A4"}
}
labels := labelIter{orig: s}
for ; !labels.done(); labels.next() {
label := labels.label()
if label == "" {
// Empty labels are not okay. The label iterator skips the last
// label if it is empty.
if err == nil && p.verifyDNSLength {
err = &labelError{s, "A4"}
}
continue
}
if strings.HasPrefix(label, acePrefix) {
u, err2 := decode(label[len(acePrefix):])
if err2 != nil {
if err == nil {
err = err2
}
// Spec says keep the old label.
continue
}
labels.set(u)
if err == nil && p.fromPuny != nil {
err = p.fromPuny(p, u)
}
if err == nil {
// This should be called on NonTransitional, according to the
// spec, but that currently does not have any effect. Use the
// original profile to preserve options.
err = p.validateLabel(u)
}
} else if err == nil {
err = p.validateLabel(label)
}
}
if toASCII {
for labels.reset(); !labels.done(); labels.next() {
label := labels.label()
if !ascii(label) {
a, err2 := encode(acePrefix, label)
if err == nil {
err = err2
}
label = a
labels.set(a)
}
n := len(label)
if p.verifyDNSLength && err == nil && (n == 0 || n > 63) {
err = &labelError{label, "A4"}
}
}
}
s = labels.result()
if toASCII && p.verifyDNSLength && err == nil {
// Compute the length of the domain name minus the root label and its dot.
n := len(s)
if n > 0 && s[n-1] == '.' {
n--
}
if len(s) < 1 || n > 253 {
err = &labelError{s, "A4"}
}
}
return s, err
}
func normalize(p *Profile, s string) (string, error) {
return norm.NFC.String(s), nil
}
func validateRegistration(p *Profile, s string) (string, error) {
if !norm.NFC.IsNormalString(s) {
return s, &labelError{s, "V1"}
}
for i := 0; i < len(s); {
v, sz := trie.lookupString(s[i:])
// Copy bytes not copied so far.
switch p.simplify(info(v).category()) {
// TODO: handle the NV8 defined in the Unicode idna data set to allow
// for strict conformance to IDNA2008.
case valid, deviation:
case disallowed, mapped, unknown, ignored:
r, _ := utf8.DecodeRuneInString(s[i:])
return s, runeError(r)
}
i += sz
}
return s, nil
}
func validateAndMap(p *Profile, s string) (string, error) {
var (
err error
b []byte
k int
)
for i := 0; i < len(s); {
v, sz := trie.lookupString(s[i:])
start := i
i += sz
// Copy bytes not copied so far.
switch p.simplify(info(v).category()) {
case valid:
continue
case disallowed:
if err == nil {
r, _ := utf8.DecodeRuneInString(s[start:])
err = runeError(r)
}
continue
case mapped, deviation:
b = append(b, s[k:start]...)
b = info(v).appendMapping(b, s[start:i])
case ignored:
b = append(b, s[k:start]...)
// drop the rune
case unknown:
b = append(b, s[k:start]...)
b = append(b, "\ufffd"...)
}
k = i
}
if k == 0 {
// No changes so far.
s = norm.NFC.String(s)
} else {
b = append(b, s[k:]...)
if norm.NFC.QuickSpan(b) != len(b) {
b = norm.NFC.Bytes(b)
}
// TODO: the punycode converters require strings as input.
s = string(b)
}
return s, err
}
// A labelIter allows iterating over domain name labels.
type labelIter struct {
orig string
slice []string
curStart int
curEnd int
i int
}
func (l *labelIter) reset() {
l.curStart = 0
l.curEnd = 0
l.i = 0
}
func (l *labelIter) done() bool {
return l.curStart >= len(l.orig)
}
func (l *labelIter) result() string {
if l.slice != nil {
return strings.Join(l.slice, ".")
}
return l.orig
}
func (l *labelIter) label() string {
if l.slice != nil {
return l.slice[l.i]
}
p := strings.IndexByte(l.orig[l.curStart:], '.')
l.curEnd = l.curStart + p
if p == -1 {
l.curEnd = len(l.orig)
}
return l.orig[l.curStart:l.curEnd]
}
// next sets the value to the next label. It skips the last label if it is empty.
func (l *labelIter) next() {
l.i++
if l.slice != nil {
if l.i >= len(l.slice) || l.i == len(l.slice)-1 && l.slice[l.i] == "" {
l.curStart = len(l.orig)
}
} else {
l.curStart = l.curEnd + 1
if l.curStart == len(l.orig)-1 && l.orig[l.curStart] == '.' {
l.curStart = len(l.orig)
}
}
}
func (l *labelIter) set(s string) {
if l.slice == nil {
l.slice = strings.Split(l.orig, ".")
}
l.slice[l.i] = s
}
// acePrefix is the ASCII Compatible Encoding prefix.
const acePrefix = "xn--"
func (p *Profile) simplify(cat category) category {
switch cat {
case disallowedSTD3Mapped:
if p.useSTD3Rules {
cat = disallowed
} else {
cat = mapped
}
case disallowedSTD3Valid:
if p.useSTD3Rules {
cat = disallowed
} else {
cat = valid
}
case deviation:
if !p.transitional {
cat = valid
}
case validNV8, validXV8:
// TODO: handle V2008
cat = valid
}
return cat
}
func validateFromPunycode(p *Profile, s string) error {
if !norm.NFC.IsNormalString(s) {
return &labelError{s, "V1"}
}
for i := 0; i < len(s); {
v, sz := trie.lookupString(s[i:])
if c := p.simplify(info(v).category()); c != valid && c != deviation {
return &labelError{s, "V6"}
}
i += sz
}
return nil
}
const (
zwnj = "\u200c"
zwj = "\u200d"
)
type joinState int8
const (
stateStart joinState = iota
stateVirama
stateBefore
stateBeforeVirama
stateAfter
stateFAIL
)
var joinStates = [][numJoinTypes]joinState{
stateStart: {
joiningL: stateBefore,
joiningD: stateBefore,
joinZWNJ: stateFAIL,
joinZWJ: stateFAIL,
joinVirama: stateVirama,
},
stateVirama: {
joiningL: stateBefore,
joiningD: stateBefore,
},
stateBefore: {
joiningL: stateBefore,
joiningD: stateBefore,
joiningT: stateBefore,
joinZWNJ: stateAfter,
joinZWJ: stateFAIL,
joinVirama: stateBeforeVirama,
},
stateBeforeVirama: {
joiningL: stateBefore,
joiningD: stateBefore,
joiningT: stateBefore,
},
stateAfter: {
joiningL: stateFAIL,
joiningD: stateBefore,
joiningT: stateAfter,
joiningR: stateStart,
joinZWNJ: stateFAIL,
joinZWJ: stateFAIL,
joinVirama: stateAfter, // no-op as we can't accept joiners here
},
stateFAIL: {
0: stateFAIL,
joiningL: stateFAIL,
joiningD: stateFAIL,
joiningT: stateFAIL,
joiningR: stateFAIL,
joinZWNJ: stateFAIL,
joinZWJ: stateFAIL,
joinVirama: stateFAIL,
},
}
// validateLabel validates the criteria from Section 4.1. Item 1, 4, and 6 are
// already implicitly satisfied by the overall implementation.
func (p *Profile) validateLabel(s string) error {
if s == "" {
if p.verifyDNSLength {
return &labelError{s, "A4"}
}
return nil
}
if p.bidirule != nil && !p.bidirule(s) {
return &labelError{s, "B"}
}
if p.checkHyphens {
if len(s) > 4 && s[2] == '-' && s[3] == '-' {
return &labelError{s, "V2"}
}
if s[0] == '-' || s[len(s)-1] == '-' {
return &labelError{s, "V3"}
}
}
if !p.checkJoiners {
return nil
}
trie := p.trie // p.checkJoiners is only set if trie is set.
// TODO: merge the use of this in the trie.
v, sz := trie.lookupString(s)
x := info(v)
if x.isModifier() {
return &labelError{s, "V5"}
}
// Quickly return in the absence of zero-width (non) joiners.
if strings.Index(s, zwj) == -1 && strings.Index(s, zwnj) == -1 {
return nil
}
st := stateStart
for i := 0; ; {
jt := x.joinType()
if s[i:i+sz] == zwj {
jt = joinZWJ
} else if s[i:i+sz] == zwnj {
jt = joinZWNJ
}
st = joinStates[st][jt]
if x.isViramaModifier() {
st = joinStates[st][joinVirama]
}
if i += sz; i == len(s) {
break
}
v, sz = trie.lookupString(s[i:])
x = info(v)
}
if st == stateFAIL || st == stateAfter {
return &labelError{s, "C"}
}
return nil
}
func ascii(s string) bool {
for i := 0; i < len(s); i++ {
if s[i] >= utf8.RuneSelf {
return false
}
}
return true
}