gno.land/r/moul/x/daily/wrapped/v0⧉

1// Package wrapped is an accounting-only port of Wrapped Ether (WETH).2//3// The canonical WETH contract lets anyone lock native ETH and mint a 1:14// ERC-20 representation (and burn it back). On gno.land / sapphire there is no5// msg.value / payable, so there is NO real coin transfer here: Deposit and6// Withdraw are pure accounting operations that model the wrap/unwrap. Balances7// and totalSupply are plain uint64 ledgers kept in an avl.Tree.8package wrapped910import (11	"strconv"1213	"chain"14	"chain/runtime/unsafe"1516	"gno.land/p/nt/avl/v0"17)1819// balances maps owner address (string) -> wrapped balance (uint64).20var (21	balances    avl.Tree22	totalSupply uint6423)2425// Deposit wraps `amount` units of the (notional) native coin, crediting the26// caller's wrapped balance and the global totalSupply. Accounting only: no real27// coin ever moves — it models locking native funds to mint the wrapped token.28func Deposit(cur realm, amount uint64) {29	if amount == 0 {30		panic("wrapped: deposit amount must be > 0")31	}32	owner := unsafe.PreviousRealm().Address()33	setBalance(owner, balanceOf(owner)+amount)34	totalSupply += amount35	chain.Emit("Deposit", "dst", owner.String(), "wad", strconv.FormatUint(amount, 10))36}3738// Withdraw unwraps `amount` units, burning them from the caller's balance and39// from totalSupply. Panics if the caller lacks the balance.40func Withdraw(cur realm, amount uint64) {41	if amount == 0 {42		panic("wrapped: withdraw amount must be > 0")43	}44	owner := unsafe.PreviousRealm().Address()45	bal := balanceOf(owner)46	if bal < amount {47		panic("wrapped: insufficient balance")48	}49	setBalance(owner, bal-amount)50	totalSupply -= amount51	chain.Emit("Withdrawal", "src", owner.String(), "wad", strconv.FormatUint(amount, 10))52}5354// Transfer moves `amount` wrapped units from the caller to `to`.55func Transfer(cur realm, to address, amount uint64) {56	if amount == 0 {57		panic("wrapped: transfer amount must be > 0")58	}59	from := unsafe.PreviousRealm().Address()60	if from == to {61		panic("wrapped: cannot transfer to self")62	}63	fromBal := balanceOf(from)64	if fromBal < amount {65		panic("wrapped: insufficient balance")66	}67	setBalance(from, fromBal-amount)68	setBalance(to, balanceOf(to)+amount)69	chain.Emit("Transfer", "src", from.String(), "dst", to.String(), "wad", strconv.FormatUint(amount, 10))70}7172// balanceOf returns the wrapped balance of `owner` (read-only, not crossing).73func balanceOf(owner address) uint64 {74	v := balances.Get(owner.String())75	if v == nil {76		return 077	}78	return v.(uint64)79}8081// BalanceOf is the exported read-only accessor for a single owner.82func BalanceOf(owner address) uint64 { return balanceOf(owner) }8384// TotalSupply returns the total amount of wrapped units in existence.85func TotalSupply() uint64 { return totalSupply }8687func setBalance(owner address, amount uint64) {88	if amount == 0 {89		balances.Remove(owner.String())90		return91	}92	balances.Set(owner.String(), amount)93}9495// ---- pure/read-only helpers (unit-tested) ----9697// canDebit reports whether `bal` can cover `amount` for a burn/transfer.98func canDebit(bal, amount uint64) bool {99	return amount > 0 && bal >= amount100}101102// formatUnits renders a raw uint64 amount as a decimal string.103func formatUnits(n uint64) string {104	return strconv.FormatUint(n, 10)105}106107// Render shows the total supply and a table of non-zero balances.108func Render(path string) string {109	out := "# Wrapped (WETH-style, accounting-only)\n\n"110	out += "Deposit mints wrapped units, Withdraw burns them. No real coins move — this is a pure ledger.\n\n"111	out += "**Total supply:** " + formatUnits(totalSupply) + "\n\n"112113	if balances.Size() == 0 {114		out += "_No balances yet. Call `Deposit` to wrap some units._\n"115		return out116	}117118	out += "| Owner | Balance |\n|---|---:|\n"119	balances.Iterate("", "", func(key string, value interface{}) bool {120		out += "| `" + key + "` | " + formatUnits(value.(uint64)) + " |\n"121		return false122	})123	return out124}125