gno.land/r/moul/x/daily/erc1155/v0⧉

1// Package erc1155 is an idiomatic gno.land port of the Solidity ERC-11552// multi-token standard. A single realm tracks many distinct token ids, each3// with its own fungible balances. Balances are keyed by (owner, id) in an4// avl.Tree so Render can iterate deterministically.5package erc115567import (8	"strconv"9	"strings"1011	"chain"12	"chain/runtime/unsafe"1314	"gno.land/p/nt/avl/v0"15)1617// balances maps "<owner>:<id>" -> uint64 amount.18var balances avl.Tree1920// supply maps "<id>" -> uint64 total minted for that id.21var supply avl.Tree2223func balKey(owner address, id int) string {24	return owner.String() + ":" + strconv.Itoa(id)25}2627func supKey(id int) string {28	return strconv.Itoa(id)29}3031func getBalance(owner address, id int) uint64 {32	k := balKey(owner, id)33	if !balances.Has(k) {34		return 035	}36	return balances.Get(k).(uint64)37}3839func setBalance(owner address, id int, amount uint64) {40	k := balKey(owner, id)41	if amount == 0 {42		balances.Remove(k)43		return44	}45	balances.Set(k, amount)46}4748func getSupply(id int) uint64 {49	k := supKey(id)50	if !supply.Has(k) {51		return 052	}53	return supply.Get(k).(uint64)54}5556// Mint creates `amount` units of token `id` and credits them to `to`.57func Mint(cur realm, to address, id int, amount uint64) {58	if !to.IsValid() {59		panic("erc1155: mint to invalid address")60	}61	if amount == 0 {62		panic("erc1155: mint amount must be > 0")63	}64	setBalance(to, id, getBalance(to, id)+amount)65	supply.Set(supKey(id), getSupply(id)+amount)6667	operator := unsafe.PreviousRealm().Address()68	chain.Emit("Mint",69		"operator", operator.String(),70		"to", to.String(),71		"id", strconv.Itoa(id),72		"amount", strconv.FormatUint(amount, 10),73	)74}7576// TransferSingle moves `amount` of token `id` from the caller to `to`.77func TransferSingle(cur realm, to address, id int, amount uint64) {78	if !to.IsValid() {79		panic("erc1155: transfer to invalid address")80	}81	if amount == 0 {82		panic("erc1155: transfer amount must be > 0")83	}84	from := unsafe.PreviousRealm().Address()85	fromBal := getBalance(from, id)86	if fromBal < amount {87		panic("erc1155: insufficient balance")88	}89	setBalance(from, id, fromBal-amount)90	setBalance(to, id, getBalance(to, id)+amount)9192	chain.Emit("TransferSingle",93		"from", from.String(),94		"to", to.String(),95		"id", strconv.Itoa(id),96		"amount", strconv.FormatUint(amount, 10),97	)98}99100// BalanceOf returns the amount of token `id` held by `owner`.101func BalanceOf(owner address, id int) uint64 {102	return getBalance(owner, id)103}104105// TotalSupply returns the total amount minted of token `id`.106func TotalSupply(id int) uint64 {107	return getSupply(id)108}109110// Render prints a balances table and a per-id supply table.111func Render(path string) string {112	var b strings.Builder113	b.WriteString("# ERC-1155 Multi-Token\n\n")114	b.WriteString("A single realm holding many fungible token ids. ")115	b.WriteString("Balances are keyed by `(owner, id)`.\n\n")116117	b.WriteString("## Balances\n\n")118	if balances.Size() == 0 {119		b.WriteString("_No balances yet. Call `Mint` to create tokens._\n\n")120	} else {121		b.WriteString("| Owner | ID | Amount |\n")122		b.WriteString("|---|---|---|\n")123		balances.Iterate("", "", func(key string, value interface{}) bool {124			owner, id := splitBalKey(key)125			b.WriteString("| `" + owner + "` | " + id + " | " +126				strconv.FormatUint(value.(uint64), 10) + " |\n")127			return false128		})129		b.WriteString("\n")130	}131132	b.WriteString("## Supply per ID\n\n")133	if supply.Size() == 0 {134		b.WriteString("_No tokens minted._\n")135	} else {136		b.WriteString("| ID | Total Supply |\n")137		b.WriteString("|---|---|\n")138		supply.Iterate("", "", func(key string, value interface{}) bool {139			b.WriteString("| " + key + " | " +140				strconv.FormatUint(value.(uint64), 10) + " |\n")141			return false142		})143	}144145	return b.String()146}147148// splitBalKey splits a "<owner>:<id>" balance key. The owner (a bech32149// address) contains no ':', so the id is the substring after the last ':'.150func splitBalKey(key string) (owner, id string) {151	i := strings.LastIndex(key, ":")152	if i < 0 {153		return key, ""154	}155	return key[:i], key[i+1:]156}157