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gotosocial/vendor/mvdan.cc/xurls/v2/xurls.go

201 lines
7.6 KiB
Go

// Copyright (c) 2015, Daniel Martí <mvdan@mvdan.cc>
// See LICENSE for licensing information
// Package xurls extracts urls from plain text using regular expressions.
package xurls
import (
"regexp"
"strings"
"sync"
"unicode/utf8"
)
//go:generate go run ./generate/tldsgen
//go:generate go run ./generate/schemesgen
//go:generate go run ./generate/unicodegen
const (
// pathCont is based on https://www.rfc-editor.org/rfc/rfc3987#section-2.2
// but does not match separators anywhere or most puncutation in final position,
// to avoid creating asymmetries like
// `Did you know that **<a href="...">https://example.com/**</a> is reserved for documentation?`
// from `Did you know that **https://example.com/** is reserved for documentation?`.
unreservedChar = `a-zA-Z0-9\-._~`
endUnreservedChar = `a-zA-Z0-9\-_~`
midSubDelimChar = `!$&'*+,;=`
endSubDelimChar = `$&+=`
midIPathSegmentChar = unreservedChar + `%` + midSubDelimChar + `:@` + allowedUcsChar
endIPathSegmentChar = endUnreservedChar + `%` + endSubDelimChar + allowedUcsCharMinusPunc
iPrivateChar = `\x{E000}-\x{F8FF}\x{F0000}-\x{FFFFD}\x{100000}-\x{10FFFD}`
midIChar = `/?#\\` + midIPathSegmentChar + iPrivateChar
endIChar = `/#` + endIPathSegmentChar + iPrivateChar
wellParen = `\((?:[` + midIChar + `]|\([` + midIChar + `]*\))*\)`
wellBrack = `\[(?:[` + midIChar + `]|\[[` + midIChar + `]*\])*\]`
wellBrace = `\{(?:[` + midIChar + `]|\{[` + midIChar + `]*\})*\}`
wellAll = wellParen + `|` + wellBrack + `|` + wellBrace
pathCont = `(?:[` + midIChar + `]*(?:` + wellAll + `|[` + endIChar + `]))+`
letter = `\p{L}`
mark = `\p{M}`
number = `\p{N}`
iriChar = letter + mark + number
iri = `[` + iriChar + `](?:[` + iriChar + `\-]*[` + iriChar + `])?`
subdomain = `(?:` + iri + `\.)+`
octet = `(?:25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9])`
ipv4Addr = octet + `\.` + octet + `\.` + octet + `\.` + octet
// ipv6Addr is based on https://datatracker.ietf.org/doc/html/rfc4291#section-2.2
// with a specific alternative for each valid count of leading 16-bit hexadecimal "chomps"
// that have not been replaced with a `::` elision.
h4 = `[0-9a-fA-F]{1,4}`
ipv6AddrMinusEmpty = `(?:` +
// 7 colon-terminated chomps, followed by a final chomp or the rest of an elision.
`(?:` + h4 + `:){7}(?:` + h4 + `|:)|` +
// 6 chomps, followed by an IPv4 address or elision with final chomp or final elision.
`(?:` + h4 + `:){6}(?:` + ipv4Addr + `|:` + h4 + `|:)|` +
// 5 chomps, followed by an elision with optional IPv4 or up to 2 final chomps.
`(?:` + h4 + `:){5}(?::` + ipv4Addr + `|(?::` + h4 + `){1,2}|:)|` +
// 4 chomps, followed by an elision with optional IPv4 (optionally preceded by a chomp) or
// up to 3 final chomps.
`(?:` + h4 + `:){4}(?:(?::` + h4 + `){0,1}:` + ipv4Addr + `|(?::` + h4 + `){1,3}|:)|` +
// 3 chomps, followed by an elision with optional IPv4 (preceded by up to 2 chomps) or
// up to 4 final chomps.
`(?:` + h4 + `:){3}(?:(?::` + h4 + `){0,2}:` + ipv4Addr + `|(?::` + h4 + `){1,4}|:)|` +
// 2 chomps, followed by an elision with optional IPv4 (preceded by up to 3 chomps) or
// up to 5 final chomps.
`(?:` + h4 + `:){2}(?:(?::` + h4 + `){0,3}:` + ipv4Addr + `|(?::` + h4 + `){1,5}|:)|` +
// 1 chomp, followed by an elision with optional IPv4 (preceded by up to 4 chomps) or
// up to 6 final chomps.
`(?:` + h4 + `:){1}(?:(?::` + h4 + `){0,4}:` + ipv4Addr + `|(?::` + h4 + `){1,6}|:)|` +
// elision, followed by optional IPv4 (preceded by up to 5 chomps) or
// up to 7 final chomps.
// `:` is an intentionally omitted alternative, to avoid matching `::`.
`:(?:(?::` + h4 + `){0,5}:` + ipv4Addr + `|(?::` + h4 + `){1,7})` +
`)`
ipv6Addr = `(?:` + ipv6AddrMinusEmpty + `|::)`
ipAddrMinusEmpty = `(?:` + ipv6AddrMinusEmpty + `|\b` + ipv4Addr + `\b)`
port = `(?::[0-9]*)?`
)
// AnyScheme can be passed to StrictMatchingScheme to match any possibly valid
// scheme, and not just the known ones.
var AnyScheme = `(?:[a-zA-Z][a-zA-Z.\-+]*://|` + anyOf(SchemesNoAuthority...) + `:)`
// SchemesNoAuthority is a sorted list of some well-known url schemes that are
// followed by ":" instead of "://". The list includes both officially
// registered and unofficial schemes.
var SchemesNoAuthority = []string{
`bitcoin`, // Bitcoin
`cid`, // Content-ID
`file`, // Files
`magnet`, // Torrent magnets
`mailto`, // Mail
`mid`, // Message-ID
`sms`, // SMS
`tel`, // Telephone
`xmpp`, // XMPP
}
// SchemesUnofficial is a sorted list of some well-known url schemes which
// aren't officially registered just yet. They tend to correspond to software.
//
// Mostly collected from https://en.wikipedia.org/wiki/List_of_URI_schemes#Unofficial_but_common_URI_schemes.
var SchemesUnofficial = []string{
`gemini`, // gemini
`jdbc`, // Java database Connectivity
`moz-extension`, // Firefox extension
`postgres`, // PostgreSQL (short form)
`postgresql`, // PostgreSQL
`slack`, // Slack
`zoommtg`, // Zoom (desktop)
`zoomus`, // Zoom (mobile)
}
// The regular expressions are compiled when the API is first called.
// Any subsequent calls will use the same regular expression pointers.
//
// We do not need to make a copy of them for each API call,
// as Copy is now only useful if one copy calls Longest but not another,
// and we always call Longest after compiling the regular expression.
var (
strictRe *regexp.Regexp
strictInit sync.Once
relaxedRe *regexp.Regexp
relaxedInit sync.Once
)
func anyOf(strs ...string) string {
var b strings.Builder
b.WriteString("(?:")
for i, s := range strs {
if i != 0 {
b.WriteByte('|')
}
b.WriteString(regexp.QuoteMeta(s))
}
b.WriteByte(')')
return b.String()
}
func strictExp() string {
schemes := `(?:(?i)(?:` + anyOf(Schemes...) + `|` + anyOf(SchemesUnofficial...) + `)://|` + anyOf(SchemesNoAuthority...) + `:)`
return schemes + pathCont
}
func relaxedExp() string {
var asciiTLDs, unicodeTLDs []string
for i, tld := range TLDs {
if tld[0] >= utf8.RuneSelf {
asciiTLDs = TLDs[:i:i]
unicodeTLDs = TLDs[i:]
break
}
}
punycode := `xn--[a-z0-9-]+`
// Use \b to make sure ASCII TLDs are immediately followed by a word break.
// We can't do that with unicode TLDs, as they don't see following
// whitespace as a word break.
tlds := `(?:(?i)` + punycode + `|` + anyOf(append(asciiTLDs, PseudoTLDs...)...) + `\b|` + anyOf(unicodeTLDs...) + `)`
domain := subdomain + tlds
hostName := `(?:` + domain + `|\[` + ipv6Addr + `\]|\b` + ipv4Addr + `\b)`
webURL := hostName + port + `(?:/` + pathCont + `|/)?`
email := `[a-zA-Z0-9._%\-+]+@` + domain
return strictExp() + `|` + webURL + `|` + email + `|` + ipv6AddrMinusEmpty
}
// Strict produces a regexp that matches any URL with a scheme in either the
// Schemes or SchemesNoAuthority lists.
func Strict() *regexp.Regexp {
strictInit.Do(func() {
strictRe = regexp.MustCompile(strictExp())
strictRe.Longest()
})
return strictRe
}
// Relaxed produces a regexp that matches any URL matched by Strict, plus any
// URL with no scheme or email address.
func Relaxed() *regexp.Regexp {
relaxedInit.Do(func() {
relaxedRe = regexp.MustCompile(relaxedExp())
relaxedRe.Longest()
})
return relaxedRe
}
// StrictMatchingScheme produces a regexp similar to Strict, but requiring that
// the scheme match the given regular expression. See AnyScheme too.
func StrictMatchingScheme(exp string) (*regexp.Regexp, error) {
strictMatching := `(?i)(?:` + exp + `)(?-i)` + pathCont
re, err := regexp.Compile(strictMatching)
if err != nil {
return nil, err
}
re.Longest()
return re, nil
}