gno.land/p/samcrew/launchpad/meta/v1⧉

1// Package meta validates launch metadata and addresses, and encodes text2// safely for JSON and Markdown.3package meta45import (6	"errors"7	"strings"8	"unicode"9	"unicode/utf8"10)1112var (13	ErrName        = errors.New("launchpad/meta: name must be 1-32 bytes of printable text without markup characters")14	ErrTicker      = errors.New("launchpad/meta: ticker must be 1-10 characters A-Z or 0-9")15	ErrDescription = errors.New("launchpad/meta: description must be at most 280 bytes of printable text without markup characters")16	ErrImage       = errors.New("launchpad/meta: image must be an ipfs:// or https:// URI of at most 200 bytes")17	ErrWebsite     = errors.New("launchpad/meta: website must be an https:// URL of at most 200 bytes")18	ErrHandle      = errors.New("launchpad/meta: handle must be 1-32 characters A-Z, a-z, 0-9 or _")19)2021const hexDigits = "0123456789abcdef"2223// The chain decodes four texts to the same address: the bech32 form it gives24// a caller, that form in capitals, and the bech32m checksum in either case.25// State keyed by the text, such as a token balance or a role, recorded under26// any of the other three is something no caller can ever reach.2728// bech32Value holds, for each character of the bech32 alphabet29// "qpzry9x8gf2tvdw0s3jn54khce6mua7l", its 5-bit value plus one. Zero marks30// every other byte, capitals included.31var bech32Value = [256]byte{32	'q': 1, 'p': 2, 'z': 3, 'r': 4, 'y': 5, '9': 6, 'x': 7, '8': 8,33	'g': 9, 'f': 10, '2': 11, 't': 12, 'v': 13, 'd': 14, 'w': 15, '0': 16,34	's': 17, '3': 18, 'j': 19, 'n': 20, '5': 21, '4': 22, 'k': 23, 'h': 24,35	'c': 25, 'e': 26, '6': 27, 'm': 28, 'u': 29, 'a': 30, '7': 31, 'l': 32,36}3738// bech32Gen[t] is the XOR of the BIP-173 generators selected by the five39// bits of t: one table read per character instead of five tests.40var bech32Gen = [32]uint32{41	0x00000000, 0x3b6a57b2, 0x26508e6d, 0x1d3ad9df,42	0x1ea119fa, 0x25cb4e48, 0x38f19797, 0x039bc025,43	0x3d4233dd, 0x0628646f, 0x1b12bdb0, 0x2078ea02,44	0x23e32a27, 0x18897d95, 0x05b3a44a, 0x3ed9f3f8,45	0x2a1462b3, 0x117e3501, 0x0c44ecde, 0x372ebb6c,46	0x34b57b49, 0x0fdf2cfb, 0x12e5f524, 0x298fa296,47	0x1756516e, 0x2c3c06dc, 0x3106df03, 0x0a6c88b1,48	0x09f74894, 0x329d1f26, 0x2fa7c6f9, 0x14cd914b,49}5051// The checksum state once the address prefix "g" has been absorbed, which52// BIP-173 expands to the values 3, 0, 7.53const bech32PrefixState uint32 = 0x8c075455// ValidAddress reports whether a is an account or realm address written the56// one way the chain gives it to a caller: "g1", then 38 lowercase bech3257// characters whose checksum is the original bech32 one. It reads the text58// itself: decoding and re-encoding it costs far more gas.59func ValidAddress(a address) bool {60	s := string(a)61	if len(s) != 40 || s[0] != 'g' || s[1] != '1' {62		return false63	}64	chk := bech32PrefixState65	for i := 2; i < 40; i++ {66		v := bech32Value[s[i]]67		if v == 0 {68			return false69		}70		chk = (chk&0x1ffffff)<<5 ^ uint32(v-1) ^ bech32Gen[chk>>25]71	}72	return chk == 1 // 1 is bech32; bech32m ends on 0x2bc830a373}7475func printable(s string) bool {76	if !utf8.ValidString(s) {77		return false78	}79	for _, r := range s {80		if !unicode.IsPrint(r) {81			return false82		}83	}84	return true85}8687func Name(s string) error {88	if len(s) < 1 || len(s) > 32 || !printable(s) || strings.ContainsAny(s, "[]()*#<>`|\\") || strings.TrimSpace(s) != s {89		return ErrName90	}91	return nil92}9394func Ticker(s string) error {95	if len(s) < 1 || len(s) > 10 {96		return ErrTicker97	}98	for i := 0; i < len(s); i++ {99		c := s[i]100		if !(c >= 'A' && c <= 'Z') && !(c >= '0' && c <= '9') {101			return ErrTicker102		}103	}104	return nil105}106107func Description(s string) error {108	if len(s) > 280 || !printable(s) || strings.ContainsAny(s, "[]()<>") {109		return ErrDescription110	}111	return nil112}113114func safeURI(s string, schemes []string) bool {115	if len(s) > 200 {116		return false117	}118	matched := false119	for _, p := range schemes {120		if strings.HasPrefix(s, p) && len(s) > len(p) {121			matched = true122		}123	}124	if !matched {125		return false126	}127	for i := 0; i < len(s); i++ {128		c := s[i]129		if c <= 0x20 || c >= 0x7f || strings.IndexByte("\"'<>\\`()[]{}|^", c) >= 0 {130			return false131		}132	}133	return true134}135136func Image(s string) error {137	if s == "" || safeURI(s, []string{"ipfs://", "https://"}) {138		return nil139	}140	return ErrImage141}142143func Website(s string) error {144	if s == "" || safeURI(s, []string{"https://"}) {145		return nil146	}147	return ErrWebsite148}149150func Handle(s string) error {151	if s == "" {152		return nil153	}154	if len(s) > 32 {155		return ErrHandle156	}157	for i := 0; i < len(s); i++ {158		c := s[i]159		if !(c >= 'a' && c <= 'z') && !(c >= 'A' && c <= 'Z') && !(c >= '0' && c <= '9') && c != '_' {160			return ErrHandle161		}162	}163	return nil164}165166// JSONString quotes s as a JSON string. Control bytes become \u00XX so the167// value survives the frontend's qeval double decode.168func JSONString(s string) string {169	var b strings.Builder170	b.WriteByte('"')171	for i := 0; i < len(s); i++ {172		c := s[i]173		switch {174		case c == '"':175			b.WriteString(`\"`)176		case c == '\\':177			b.WriteString(`\\`)178		case c < 0x20:179			b.WriteString(`\u00`)180			b.WriteByte(hexDigits[c>>4])181			b.WriteByte(hexDigits[c&0xf])182		default:183			b.WriteByte(c)184		}185	}186	b.WriteByte('"')187	return b.String()188}189190// EscapeMarkdown backslash-escapes every Markdown control character.191func EscapeMarkdown(s string) string {192	var b strings.Builder193	for i := 0; i < len(s); i++ {194		c := s[i]195		if strings.IndexByte("\\`*_{}[]()#+-.!|<>~", c) >= 0 {196			b.WriteByte('\\')197		}198		b.WriteByte(c)199	}200	return b.String()201}202