validate.gno

  1package nslogic
  2
  3import (
  4	"strings"
  5
  6	"gno.land/p/nt/ufmt/v0"
  7	"gno.land/r/nym-mnsrehearsal001/nsdata/v1"
  8)
  9
 10// THE LABEL RULE IS WRITTEN OUT, NOT COMPILED.
 11//
 12// It used to be a regexp, and that regexp was the single most expensive
 13// thing in this realm — by a wide margin, and not by a little. Measured
 14// on sapphire-1 with vm/qstorage against purpose-built probe realms:
 15//
 16//	a realm with code and no package-level state      2,711 bytes
 17//	the same realm plus ONE compiled regexp         154,877 bytes
 18//
 19// A compiled regexp is an object graph, and gno charges 100 ugnot for
 20// every byte of it, forever. That one variable was 15.2 GNOT of the
 21// 22.5 GNOT it costs to deploy this realm — about 68% of the bill, to
 22// enforce a rule that fits in thirty lines.
 23//
 24// The second regexp was worse, because it was compiled LAZILY and cached
 25// in a package-level var. That does not avoid the cost, it MOVES it: the
 26// first person to register a name after a fresh deploy would have had
 27// their transaction grow this realm's storage by 150KB and been charged
 28// ~15 GNOT of deposit for it. Confirmed by probe, not inferred — a realm
 29// deployed at 2,711 bytes went to 154,149 the moment one call compiled
 30// and cached a regexp, billed to the caller. Somebody buying a ten-cent
 31// name would have been asked for fifteen GNOT.
 32//
 33// The hand-written version is also 6x cheaper in gas on every call
 34// (1.06M against 6.67M), so there is no axis on which the regexp was
 35// the better choice. It read better. That was the whole of its case.
 36//
 37// WHAT THIS COSTS US. The pattern is no longer admin-tunable at runtime:
 38// changing the rule now means redeploying this realm. That is a fair
 39// trade at 7 GNOT a deploy, it was never a rule that should change
 40// casually, and SetLabelPattern refuses anything but the implemented
 41// pattern so the stored string can never describe rules the code does
 42// not enforce.
 43
 44// labelRule is the pattern this realm implements, kept as a string so
 45// nsdata, the error messages and the site all quote the same thing.
 46const labelRule = `^[a-z0-9]+(-[a-z0-9]+)*$`
 47
 48// matchesLabelRule is that pattern, by hand: lowercase letters and
 49// digits, single hyphens between them, none at either end.
 50func matchesLabelRule(s string) bool {
 51	if s == "" {
 52		return false
 53	}
 54	prevHyphen := true // a leading hyphen is not allowed
 55	for i := 0; i < len(s); i++ {
 56		c := s[i]
 57		switch {
 58		case c >= 'a' && c <= 'z', c >= '0' && c <= '9':
 59			prevHyphen = false
 60		case c == '-':
 61			if prevHyphen {
 62				return false // leading, or two in a row
 63			}
 64			prevHyphen = true
 65		default:
 66			return false
 67		}
 68	}
 69	return !prevHyphen // nor a trailing one
 70}
 71
 72// looksLikeAddress was `^g1[a-z0-9]{20,38}$`. Anything shaped like a real
 73// gno.land address is refused as a label, so a name can never be mistaken
 74// for a raw wallet address in a UI.
 75func looksLikeAddress(s string) bool {
 76	if len(s) < 22 || len(s) > 40 || !strings.HasPrefix(s, "g1") {
 77		return false
 78	}
 79	for i := 2; i < len(s); i++ {
 80		c := s[i]
 81		if !(c >= 'a' && c <= 'z') && !(c >= '0' && c <= '9') {
 82			return false
 83		}
 84	}
 85	return true
 86}
 87
 88// validateLabel — same policy as the original single-realm build (see
 89// NOTES.md for the ENS/Starname/r/sys/users research behind it). The
 90// length bounds are still read from nsdata, so they survive a swap of
 91// this realm; the character rule is now this realm's own.
 92//
 93// Call sites, and why: RegisterName/RegisterDomain only (both the
 94// first-ever mint AND reclaiming a past-grace slot — a reclaim is a
 95// genuine new mint with a new owner). RenewName/RenewDomain deliberately
 96// do NOT call this — an already-registered name must keep renewing under
 97// whatever rule was in force when it was minted.
 98func validateLabel(label string) {
 99	minLen, maxLen := nsdata.GetLabelLength()
100	if len(label) < minLen || len(label) > maxLen {
101		panic(ufmt.Sprintf("nslogic: label must be %d-%d characters", minLen, maxLen))
102	}
103	// Structural invariant, enforced regardless of what the pattern
104	// happens to allow: "*" is the separator in both the token ID
105	// (label*domain) and nsdata's storage key (domain*label). A label or
106	// domain containing one would make those encodings ambiguous and let
107	// two different names collide onto a single record.
108	if strings.Contains(label, "*") {
109		panic("nslogic: label may not contain '*'")
110	}
111	if !matchesLabelRule(label) {
112		panic("nslogic: a name is lowercase letters, digits and single hyphens between them — " + labelRule)
113	}
114	if looksLikeAddress(label) {
115		panic("nslogic: label looks like a wallet address, not allowed")
116	}
117}