igrc721.gno

 1package grc721
 2
 3// IGRC721Reader is the read-only view of an NFT. Safe to receive across
 4// realm boundaries — has no rlm-typed methods, so a malicious impl can
 5// only lie about read results (data-integrity issue), not capture cur.
 6//
 7// Writes are concrete methods on *BasicNFT / *metadataNFT / *royaltyNFT
 8// only — there is no IGRC721 writer interface. The owning realm should
 9// hold the concrete *BasicNFT in an unexported package var and expose
10// public rlm-validating wrappers like:
11//
12//	func TransferFrom(cur realm, from, to address, tid TokenID) error {
13//		caller := cur.Previous().Address()
14//		return nft.TransferFrom(caller, from, to, tid)
15//	}
16//
17// This is the Reader/Writer split — stronger than the Authority-pattern
18// because the writer interface doesn't exist at all, so no realm author
19// can accidentally expose it. See `r/demo/foo721` for the canonical
20// wrapper pattern.
21type IGRC721Reader interface {
22	Name() string
23	Symbol() string
24	TokenCount() int64
25	BalanceOf(owner address) (int64, error)
26	OwnerOf(tid TokenID) (address, error)
27	GetApproved(tid TokenID) (address, error)
28	IsApprovedForAll(owner, operator address) bool
29}
30
31type (
32	TokenID  string
33	TokenURI string
34)
35
36func (t TokenID) String() string  { return string(t) }
37func (t TokenURI) String() string { return string(t) }
38
39const (
40	MintEvent           = "Mint"
41	BurnEvent           = "Burn"
42	TransferEvent       = "Transfer"
43	ApprovalEvent       = "Approval"
44	ApprovalForAllEvent = "ApprovalForAll"
45	TokenURIUpdateEvent = "TokenUriUpdate"
46	MetadataUpdateEvent = "MetadataUpdate"
47)
48
49// NFTGetter returns a reader-only view of an NFT. Aggregators (such as
50// tokenhub) register and dispatch NFTGetters; the reader-only return
51// type means even a malicious aggregator can't be used to leak cur.
52type NFTGetter func() IGRC721Reader