taldir

list.go (6711B)

---

 // Copyright 2012 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:generate go run gen.go
 
 // Package publicsuffix provides a public suffix list based on data from
 // https://publicsuffix.org/
 //
 // A public suffix is one under which Internet users can directly register
 // names. It is related to, but different from, a TLD (top level domain).
 //
 // "com" is a TLD (top level domain). Top level means it has no dots.
 //
 // "com" is also a public suffix. Amazon and Google have registered different
 // siblings under that domain: "amazon.com" and "google.com".
 //
 // "au" is another TLD, again because it has no dots. But it's not "amazon.au".
 // Instead, it's "amazon.com.au".
 //
 // "com.au" isn't an actual TLD, because it's not at the top level (it has
 // dots). But it is an eTLD (effective TLD), because that's the branching point
 // for domain name registrars.
 //
 // Another name for "an eTLD" is "a public suffix". Often, what's more of
 // interest is the eTLD+1, or one more label than the public suffix. For
 // example, browsers partition read/write access to HTTP cookies according to
 // the eTLD+1. Web pages served from "amazon.com.au" can't read cookies from
 // "google.com.au", but web pages served from "maps.google.com" can share
 // cookies from "www.google.com", so you don't have to sign into Google Maps
 // separately from signing into Google Web Search. Note that all four of those
 // domains have 3 labels and 2 dots. The first two domains are each an eTLD+1,
 // the last two are not (but share the same eTLD+1: "google.com").
 //
 // All of these domains have the same eTLD+1:
 //   - "www.books.amazon.co.uk"
 //   - "books.amazon.co.uk"
 //   - "amazon.co.uk"
 //
 // Specifically, the eTLD+1 is "amazon.co.uk", because the eTLD is "co.uk".
 //
 // There is no closed form algorithm to calculate the eTLD of a domain.
 // Instead, the calculation is data driven. This package provides a
 // pre-compiled snapshot of Mozilla's PSL (Public Suffix List) data at
 // https://publicsuffix.org/
 package publicsuffix // import "golang.org/x/net/publicsuffix"
 
 // TODO: specify case sensitivity and leading/trailing dot behavior for
 // func PublicSuffix and func EffectiveTLDPlusOne.
 
 import (
 	"fmt"
 	"net/http/cookiejar"
 	"net/netip"
 	"strings"
 )
 
 // List implements the cookiejar.PublicSuffixList interface by calling the
 // PublicSuffix function.
 var List cookiejar.PublicSuffixList = list{}
 
 type list struct{}
 
 func (list) PublicSuffix(domain string) string {
 	ps, _ := PublicSuffix(domain)
 	return ps
 }
 
 func (list) String() string {
 	return version
 }
 
 // PublicSuffix returns the public suffix of the domain using a copy of the
 // publicsuffix.org database compiled into the library.
 //
 // icann is whether the public suffix is managed by the Internet Corporation
 // for Assigned Names and Numbers. If not, the public suffix is either a
 // privately managed domain (and in practice, not a top level domain) or an
 // unmanaged top level domain (and not explicitly mentioned in the
 // publicsuffix.org list). For example, "foo.org" and "foo.co.uk" are ICANN
 // domains, "foo.dyndns.org" is a private domain and
 // "cromulent" is an unmanaged top level domain.
 //
 // Use cases for distinguishing ICANN domains like "foo.com" from private
 // domains like "foo.appspot.com" can be found at
 // https://wiki.mozilla.org/Public_Suffix_List/Use_Cases
 func PublicSuffix(domain string) (publicSuffix string, icann bool) {
 	if _, err := netip.ParseAddr(domain); err == nil {
 		return domain, false
 	}
 
 	lo, hi := uint32(0), uint32(numTLD)
 	s, suffix, icannNode, wildcard := domain, len(domain), false, false
 loop:
 	for {
 		dot := strings.LastIndexByte(s, '.')
 		if wildcard {
 			icann = icannNode
 			suffix = 1 + dot
 		}
 		if lo == hi {
 			break
 		}
 		f := find(s[1+dot:], lo, hi)
 		if f == notFound {
 			break
 		}
 
 		u := uint32(nodes.get(f) >> (nodesBitsTextOffset + nodesBitsTextLength))
 		icannNode = u&(1<<nodesBitsICANN-1) != 0
 		u >>= nodesBitsICANN
 		u = children.get(u & (1<<nodesBitsChildren - 1))
 		lo = u & (1<<childrenBitsLo - 1)
 		u >>= childrenBitsLo
 		hi = u & (1<<childrenBitsHi - 1)
 		u >>= childrenBitsHi
 		switch u & (1<<childrenBitsNodeType - 1) {
 		case nodeTypeNormal:
 			suffix = 1 + dot
 		case nodeTypeException:
 			suffix = 1 + len(s)
 			break loop
 		}
 		u >>= childrenBitsNodeType
 		wildcard = u&(1<<childrenBitsWildcard-1) != 0
 		if !wildcard {
 			icann = icannNode
 		}
 
 		if dot == -1 {
 			break
 		}
 		s = s[:dot]
 	}
 	if suffix == len(domain) {
 		// If no rules match, the prevailing rule is "*".
 		return domain[1+strings.LastIndexByte(domain, '.'):], icann
 	}
 	return domain[suffix:], icann
 }
 
 const notFound uint32 = 1<<32 - 1
 
 // find returns the index of the node in the range [lo, hi) whose label equals
 // label, or notFound if there is no such node. The range is assumed to be in
 // strictly increasing node label order.
 func find(label string, lo, hi uint32) uint32 {
 	for lo < hi {
 		mid := lo + (hi-lo)/2
 		s := nodeLabel(mid)
 		if s < label {
 			lo = mid + 1
 		} else if s == label {
 			return mid
 		} else {
 			hi = mid
 		}
 	}
 	return notFound
 }
 
 // nodeLabel returns the label for the i'th node.
 func nodeLabel(i uint32) string {
 	x := nodes.get(i)
 	length := x & (1<<nodesBitsTextLength - 1)
 	x >>= nodesBitsTextLength
 	offset := x & (1<<nodesBitsTextOffset - 1)
 	return text[offset : offset+length]
 }
 
 // EffectiveTLDPlusOne returns the effective top level domain plus one more
 // label. For example, the eTLD+1 for "foo.bar.golang.org" is "golang.org".
 func EffectiveTLDPlusOne(domain string) (string, error) {
 	if strings.HasPrefix(domain, ".") || strings.HasSuffix(domain, ".") || strings.Contains(domain, "..") {
 		return "", fmt.Errorf("publicsuffix: empty label in domain %q", domain)
 	}
 
 	suffix, _ := PublicSuffix(domain)
 	if len(domain) <= len(suffix) {
 		return "", fmt.Errorf("publicsuffix: cannot derive eTLD+1 for domain %q", domain)
 	}
 	i := len(domain) - len(suffix) - 1
 	if domain[i] != '.' {
 		return "", fmt.Errorf("publicsuffix: invalid public suffix %q for domain %q", suffix, domain)
 	}
 	return domain[1+strings.LastIndexByte(domain[:i], '.'):], nil
 }
 
 type uint32String string
 
 func (u uint32String) get(i uint32) uint32 {
 	off := i * 4
 	u = u[off:] // help the compiler reduce bounds checks
 	return uint32(u[3]) |
 		uint32(u[2])<<8 |
 		uint32(u[1])<<16 |
 		uint32(u[0])<<24
 }
 
 type uint40String string
 
 func (u uint40String) get(i uint32) uint64 {
 	off := uint64(i * (nodesBits / 8))
 	u = u[off:] // help the compiler reduce bounds checks
 	return uint64(u[4]) |
 		uint64(u[3])<<8 |
 		uint64(u[2])<<16 |
 		uint64(u[1])<<24 |
 		uint64(u[0])<<32
 }