92 lines
2.1 KiB
Go
92 lines
2.1 KiB
Go
// Copyright (c) 2012-2014 Jeremy Latt
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// Copyright (c) 2014-2015 Edmund Huber
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// Copyright (c) 2016-2017 Daniel Oaks <daniel@danieloaks.net>
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// released under the MIT license
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package irc
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import (
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"strings"
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"golang.org/x/text/secure/precis"
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)
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const (
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casemappingName = "rfc8265"
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)
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// Casefold returns a casefolded string, without doing any name or channel character checks.
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func Casefold(str string) (string, error) {
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var err error
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oldStr := str
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// follow the stabilizing rules laid out here:
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// https://tools.ietf.org/html/draft-ietf-precis-7564bis-10.html#section-7
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for i := 0; i < 4; i++ {
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str, err = precis.UsernameCaseMapped.CompareKey(str)
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if err != nil {
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return "", err
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}
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if oldStr == str {
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break
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}
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oldStr = str
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}
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if oldStr != str {
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return "", errCouldNotStabilize
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}
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return str, nil
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}
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// CasefoldChannel returns a casefolded version of a channel name.
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func CasefoldChannel(name string) (string, error) {
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lowered, err := Casefold(name)
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if err != nil {
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return "", err
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} else if len(lowered) == 0 {
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return "", errStringIsEmpty
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}
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if lowered[0] != '#' {
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return "", errInvalidCharacter
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}
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// space can't be used
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// , is used as a separator
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// * is used in mask matching
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// ? is used in mask matching
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if strings.ContainsAny(lowered, " ,*?") {
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return "", errInvalidCharacter
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}
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return lowered, err
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}
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// CasefoldName returns a casefolded version of a nick/user name.
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func CasefoldName(name string) (string, error) {
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lowered, err := Casefold(name)
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if err != nil {
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return "", err
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} else if len(lowered) == 0 {
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return "", errStringIsEmpty
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}
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// space can't be used
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// , is used as a separator
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// * is used in mask matching
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// ? is used in mask matching
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// . denotes a server name
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// ! separates nickname from username
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// @ separates username from hostname
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// : means trailing
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// # is a channel prefix
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// ~&@%+ are channel membership prefixes
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// - I feel like disallowing
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if strings.ContainsAny(lowered, " ,*?.!@:") || strings.ContainsAny(string(lowered[0]), "#~&@%+-") {
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return "", errInvalidCharacter
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}
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return lowered, err
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}
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