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AutistMask/src/shared/uniswap.js
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harden: gate swap amounts on presence, not truthiness, so a figure always matches its token (closes #359)
Token and amount were gated on truthiness and gated independently. An address is never falsy once set but 0n is, so a hop supplying a zero amount fixed the token permanently while leaving the amount open, and the next hop's figure was rendered against the first hop's token at that token's scale -- 0.5 WETH shown as 500000000000.0000 USDT. Nine defective gates are now presence checks, and fourteen address gates were converted defensively so a sixth instance of this class cannot grow.

Zero is not one thing. Established from v4-periphery: OPEN_DELTA is 0 and V4Router substitutes the full credit unconditionally, so a zero V4 exact-in amount means "swap the whole balance" and now reads "All available (V4 open delta)" rather than 0.0000, which would assert the exact inverse. amountOutMinimum gets no such mapping and universal-router special-cases only CONTRACT_BALANCE, so a zero minimum and a zero V2/V3 amount stay literal -- a zero floor reads "None (no minimum guaranteed)".

closes #364
2026-08-23 20:45:58 +02:00

687 lines
28 KiB
JavaScript

// Decode Uniswap Universal Router execute() calldata into human-readable
// swap details. Designed to be extended with other DEX decoders later.
const { Interface, AbiCoder, getBytes, formatUnits } = require("ethers");
const { TOKEN_BY_ADDRESS } = require("./tokenList");
const { truncateAmountNeverZero } = require("./amountDisplay");
const {
resolveTokenDecimals,
unknownDecimalsAmount,
} = require("./approvalAmount");
const coder = AbiCoder.defaultAbiCoder();
const ROUTER_IFACE = new Interface([
"function execute(bytes commands, bytes[] inputs, uint256 deadline)",
]);
// Universal Router command IDs (lower 5 bits of each command byte)
const COMMAND_NAMES = {
0x00: "V3 Swap (Exact In)",
0x01: "V3 Swap (Exact Out)",
0x02: "Permit2 Transfer",
0x03: "Permit2 Permit Batch",
0x04: "Sweep",
0x05: "Transfer",
0x06: "Pay Portion",
0x08: "V2 Swap (Exact In)",
0x09: "V2 Swap (Exact Out)",
0x0a: "Permit2 Permit",
0x0b: "Wrap ETH",
0x0c: "Unwrap WETH",
0x0d: "Permit2 Transfer Batch",
0x0e: "Balance Check",
0x10: "V4 Swap",
0x11: "V3 Position Mgr Permit",
0x12: "V3 Position Mgr Call",
0x13: "V4 Initialize Pool",
0x14: "V4 Position Mgr Call",
0x21: "Execute Sub-Plan",
};
// The swap's Amount and Min. received lines land on the same approval screen,
// and Amount is carried to the wait/success/error screens as the ERC-20 line
// is, so they take the same nonzero floor: a swap of an amount below 0.0001 is
// not "0.0000", and a slippage floor of one base unit does not read as "you may
// receive nothing".
function formatAmount(raw, decimals) {
return truncateAmountNeverZero(formatUnits(raw, decimals));
}
// One wording for either side of the screen: a currency the calldata never
// named. It reads as a refusal, the same stance unknownDecimalsAmount() takes
// on a scale — not as a token name, and not as a quantity.
const UNNAMED_CURRENCY = "Unknown (not named in the calldata)";
// Explicit presence, never truthiness. Every gate in this file that guards a
// decoded value goes through here: an address is never falsy once set, but an
// amount of 0n is, and a gate that cannot tell a genuine zero from an absent
// value is the trap this decoder has now been bitten by five times.
function present(value) {
return value !== null && value !== undefined;
}
// Uniswap V4 spells "use the whole open delta" as an amount of zero:
// v4-periphery `src/libraries/ActionConstants.sol` declares
// `uint128 internal constant OPEN_DELTA = 0` ("used to signal that an action
// should use the input value of the open delta on the pool manager or of the
// balance that the contract holds"), and `src/V4Router.sol` substitutes the
// full open credit whenever an exact-in swap action's `amountIn` equals it:
//
// uint128 amountIn = params.amountIn;
// if (amountIn == ActionConstants.OPEN_DELTA) {
// amountIn = _getFullCredit(...).toUint128();
// }
//
// in both `_swapExactInputSingle` and `_swapExactInput`. Sentinel and literal
// zero are the same uint128 word, so the encoding CANNOT distinguish them —
// and the router does not try: it reads every zero as the sentinel, so in V4
// there is no such thing as an exact-in swap of literally zero. The amount is
// therefore not stated by the calldata at all; it is whatever credit is open
// at execution time. It is carried as this sentinel rather than as 0n because
// printing "0.0000" would state the exact inverse of what will happen —
// "nothing is being swapped" for a step that swaps the entire balance.
//
// `amountOutMinimum` gets no such mapping: V4Router compares it directly
// (`if (amountOut < params.amountOutMinimum) revert V4TooLittleReceived`), so
// a zero minimum is a literal zero slippage floor and is stated as one. Nor do
// the V2/V3 paths have it — universal-router's `V3SwapRouter.v3SwapExactInput`
// special-cases only `ActionConstants.CONTRACT_BALANCE` (1<<255), never zero —
// so a zero `amountIn` there is a literal zero and is displayed as one.
const OPEN_DELTA = Symbol("v4-open-delta");
// The two amount lines that state a fact instead of a quantity. Same register
// as UNNAMED_CURRENCY — a sentence in the value slot, so it cannot be misread
// as a number — and deliberately not a third phrasing of "not named": these
// say different things.
const OPEN_DELTA_AMOUNT = "All available (V4 open delta)";
const NO_MINIMUM = "None (no minimum guaranteed)";
// Permit2 amounts are uint160; the maximum is Permit2's "unbounded".
const MAX_UINT160 = BigInt("0xffffffffffffffffffffffffffffffffffffffff");
// `decimals` is null when nothing knows this token's scale. It is not
// defaulted to 18: the swap lines land on the same approval screen as the
// ERC-20 line, and a scale guessed there is what showed a 1,000 USDT swap as
// 0.000000000001. `sources` is { trackedTokens, wallets }, shaped as they are
// on `state`; resolveTokenDecimals() reads the bundled list, then those.
//
// A null `address` means UNDETERMINED — the calldata named no currency for
// that side — and is refused rather than named. It is not native ETH: Uniswap
// V4 spells native ETH as `Currency.wrap(address(0))` (v4-core
// `type Currency is address`), and a Currency is ABI-encoded as a plain
// address word, so every decode site here gets back the truthy string
// "0x0000000000000000000000000000000000000000" for it — never null. WRAP_ETH
// sets that same explicit zero address, and an UNWRAP_WETH output is caught by
// its caller before this is consulted, so nothing that genuinely is ETH
// arrives null. Naming a null ETH states the wrong asset and formats its
// amount at the wrong scale.
function tokenInfo(address, sources) {
if (!address) {
return { symbol: null, decimals: null, address: null };
}
if (address === "0x0000000000000000000000000000000000000000") {
return { symbol: "ETH", decimals: 18, address: null };
}
const t = TOKEN_BY_ADDRESS.get(address.toLowerCase());
return {
symbol: t ? t.symbol : null,
decimals: resolveTokenDecimals(address, sources),
address,
};
}
// A swap amount line. With a scale it is the token quantity; with none it is
// the base-unit integer with the unknown scale stated, the same refusal the
// ERC-20 amount line makes, so the screen has one way of saying it. `display`
// is the line on the screen, `raw` is what the status screens carry.
function amountText(raw, info) {
if (info.decimals === null) {
const unknown = unknownDecimalsAmount(raw);
return { raw: unknown, display: unknown };
}
const formatted = formatAmount(raw, info.decimals);
return {
raw: formatted,
display: formatted + (info.symbol ? " " + info.symbol : ""),
};
}
// Decode PERMIT2_PERMIT (command 0x0a) input bytes.
// ABI: ((address token, uint160 amount, uint48 expiration, uint48 nonce),
// address spender, uint256 sigDeadline), bytes signature
function decodePermit2(input) {
try {
const d = coder.decode(
[
"tuple(tuple(address,uint160,uint48,uint48),address,uint256)",
"bytes",
],
input,
);
return { token: d[0][0][0], amount: d[0][0][1], spender: d[0][1] };
} catch {
return null;
}
}
// Decode BALANCE_CHECK_ERC20 (command 0x0e) input bytes.
// ABI: (address owner, address token, uint256 minBalance)
function decodeBalanceCheck(input) {
try {
const d = coder.decode(["address", "address", "uint256"], input);
return { owner: d[0], token: d[1], minBalance: d[2] };
} catch {
return null;
}
}
// Decode V2_SWAP_EXACT_IN (command 0x08) input bytes.
// ABI: (address recipient, uint256 amountIn, uint256 amountOutMin,
// address[] path, bool payerIsUser)
function decodeV2SwapExactIn(input) {
try {
const d = coder.decode(
["address", "uint256", "uint256", "address[]", "bool"],
input,
);
return {
amountIn: d[1],
amountOutMin: d[2],
tokenIn: d[3][0],
tokenOut: d[3][d[3].length - 1],
};
} catch {
return null;
}
}
// Decode V2_SWAP_EXACT_OUT (command 0x09) input bytes.
// ABI: (address recipient, uint256 amountOut, uint256 amountInMax,
// address[] path, bool payerIsUser)
//
// Nothing calls this: decode() has no 0x09 arm, so a V2 exact-out swap gets
// its command name and no token or amount detail. Kept for the fix, which is
// https://git.eeqj.de/sneak/AutistMask/issues/283.
// eslint-disable-next-line no-unused-vars
function decodeV2SwapExactOut(input) {
try {
const d = coder.decode(
["address", "uint256", "uint256", "address[]", "bool"],
input,
);
return {
amountOut: d[1],
amountInMax: d[2],
tokenIn: d[3][0],
tokenOut: d[3][d[3].length - 1],
};
} catch {
return null;
}
}
// Decode V3 swap path (packed: token(20) + fee(3) + token(20) ...)
function decodeV3Path(pathHex) {
const hex = pathHex.startsWith("0x") ? pathHex.slice(2) : pathHex;
if (hex.length < 40) return null;
const tokenIn = "0x" + hex.slice(0, 40);
const tokenOut = "0x" + hex.slice(-40);
return { tokenIn, tokenOut };
}
// Decode V3_SWAP_EXACT_IN (command 0x00) input bytes.
// ABI: (address recipient, uint256 amountIn, uint256 amountOutMin,
// bytes path, bool payerIsUser)
function decodeV3SwapExactIn(input) {
try {
const d = coder.decode(
["address", "uint256", "uint256", "bytes", "bool"],
input,
);
const path = decodeV3Path(d[3]);
if (!path) return null;
return {
amountIn: d[1],
amountOutMin: d[2],
tokenIn: path.tokenIn,
tokenOut: path.tokenOut,
};
} catch {
return null;
}
}
// Decode WRAP_ETH (command 0x0b) input bytes.
// ABI: (address recipient, uint256 amount)
function decodeWrapEth(input) {
try {
const d = coder.decode(["address", "uint256"], input);
return { amount: d[1] };
} catch {
return null;
}
}
// V4 inner action IDs
const V4_SWAP_EXACT_IN_SINGLE = 0x06;
const V4_SWAP_EXACT_IN = 0x07;
const V4_SWAP_EXACT_OUT_SINGLE = 0x08;
const V4_SWAP_EXACT_OUT = 0x09;
const V4_SETTLE = 0x0b;
const V4_TAKE = 0x0e;
// A V4 exact-in `amountIn`, read the way V4Router reads it: zero is
// ActionConstants.OPEN_DELTA, not a quantity of zero. See the OPEN_DELTA
// comment above. The exact-OUT actions below decode no amounts at all, so
// their own OPEN_DELTA mapping on `amountOut` never reaches the screen.
function v4ExactInAmount(raw) {
return raw === 0n ? OPEN_DELTA : raw;
}
// Decode V4_SWAP (command 0x10) input bytes.
// The input is ABI-encoded as (bytes actions, bytes[] params).
// We extract token addresses from SETTLE (input) and TAKE (output) sub-actions,
// and swap amounts from the swap sub-actions.
function decodeV4Swap(input) {
try {
const d = coder.decode(["bytes", "bytes[]"], input);
const actions = getBytes(d[0]);
const params = d[1];
let settleToken = null;
let takeToken = null;
let amountIn = null;
let amountOutMin = null;
for (let i = 0; i < actions.length; i++) {
const actionId = actions[i];
try {
if (actionId === V4_SETTLE) {
// SETTLE: (address currency, uint256 maxAmount, bool payerIsUser)
const s = coder.decode(
["address", "uint256", "bool"],
params[i],
);
settleToken = s[0];
} else if (actionId === V4_TAKE) {
// TAKE: (address currency, address recipient, uint256 amount)
const t = coder.decode(
["address", "address", "uint256"],
params[i],
);
takeToken = t[0];
} else if (
actionId === V4_SWAP_EXACT_IN ||
actionId === V4_SWAP_EXACT_IN_SINGLE
) {
// Extract amounts from exact-in swap actions
if (actionId === V4_SWAP_EXACT_IN) {
// ExactInputParams: (address currencyIn,
// tuple(address,uint24,int24,address,bytes)[] path,
// uint128 amountIn, uint128 amountOutMin)
try {
const s = coder.decode(
[
"tuple(address,tuple(address,uint24,int24,address,bytes)[],uint128,uint128)",
],
params[i],
);
if (!present(settleToken)) settleToken = s[0][0];
const path = s[0][1];
if (path.length > 0 && !present(takeToken)) {
takeToken = path[path.length - 1][0];
}
if (!present(amountIn)) {
amountIn = v4ExactInAmount(s[0][2]);
}
if (!present(amountOutMin)) {
amountOutMin = s[0][3];
}
} catch {
// Fall through — SETTLE/TAKE will provide tokens
}
} else {
// ExactInputSingleParams: (tuple(address,address,uint24,int24,address) poolKey,
// bool zeroForOne, uint128 amountIn, uint128 amountOutMin, bytes hookData)
try {
const s = coder.decode(
[
"tuple(tuple(address,address,uint24,int24,address),bool,uint128,uint128,bytes)",
],
params[i],
);
const poolKey = s[0][0];
const zeroForOne = s[0][1];
if (!present(settleToken))
settleToken = zeroForOne
? poolKey[0]
: poolKey[1];
if (!present(takeToken))
takeToken = zeroForOne
? poolKey[1]
: poolKey[0];
if (!present(amountIn)) {
amountIn = v4ExactInAmount(s[0][2]);
}
if (!present(amountOutMin)) {
amountOutMin = s[0][3];
}
} catch {
// Fall through
}
}
} else if (
actionId === V4_SWAP_EXACT_OUT ||
actionId === V4_SWAP_EXACT_OUT_SINGLE
) {
if (actionId === V4_SWAP_EXACT_OUT) {
try {
const s = coder.decode(
[
"tuple(address,tuple(address,uint24,int24,address,bytes)[],uint128,uint128)",
],
params[i],
);
if (!present(takeToken)) takeToken = s[0][0];
const path = s[0][1];
if (path.length > 0 && !present(settleToken)) {
settleToken = path[path.length - 1][0];
}
} catch {
// Fall through
}
} else {
try {
const s = coder.decode(
[
"tuple(tuple(address,address,uint24,int24,address),bool,uint128,uint128,bytes)",
],
params[i],
);
const poolKey = s[0][0];
const zeroForOne = s[0][1];
if (!present(settleToken))
settleToken = zeroForOne
? poolKey[0]
: poolKey[1];
if (!present(takeToken))
takeToken = zeroForOne
? poolKey[1]
: poolKey[0];
} catch {
// Fall through
}
}
}
} catch {
// Skip sub-actions we can't decode
}
}
return {
tokenIn: settleToken,
tokenOut: takeToken,
amountIn,
amountOutMin,
};
} catch {
return null;
}
}
// Try to decode a Universal Router execute() call.
// Returns { name, description, details } matching the format used by
// the approval UI, or null if the calldata is not a recognised execute().
function decode(data, toAddress, sources) {
try {
const parsed = ROUTER_IFACE.parseTransaction({ data });
if (!parsed) return null;
const commandsBytes = getBytes(parsed.args[0]);
const inputs = parsed.args[1];
const deadline = parsed.args[2];
let inputToken = null;
let inputAmount = null;
let inputEstablished = false;
let outputToken = null;
let minOutput = null;
let hasUnwrapWeth = false;
const commandNames = [];
// THE INVARIANT: an amount and the token it is counted in always come
// from the same hop. A figure is never rendered against a token that
// did not supply it.
//
// Both sides are therefore set as a PAIR — never field by field, and
// never on truthiness. An address is never falsy once set but an
// amount of 0n is, so gating the two halves independently let a hop
// with a zero amount fix the token and leave the amount open; the next
// hop's figure was then displayed against the first hop's token, at the
// first hop's scale. A V3 USDT->WETH hop with amountIn 0 followed by a
// V2 WETH->USDC hop of 0.5e18 rendered "500000000000.0000 USDT".
//
// The input side is fixed by the first hop that states either half, the
// output side by the last, because the final leg is what the user
// receives. A half the establishing hop did not state stays null and
// the line says so, rather than being filled in from a different hop.
const setInput = (token, amount) => {
inputToken = present(token) ? token : null;
inputAmount = present(amount) ? amount : null;
inputEstablished = true;
};
const setInputOnce = (token, amount) => {
if (inputEstablished) return;
if (!present(token) && !present(amount)) return;
setInput(token, amount);
};
const setOutput = (token, amount) => {
if (!present(token) && !present(amount)) return;
outputToken = present(token) ? token : null;
minOutput = present(amount) ? amount : null;
};
for (let i = 0; i < commandsBytes.length; i++) {
const cmdId = commandsBytes[i] & 0x1f;
commandNames.push(
COMMAND_NAMES[cmdId] ||
"Command 0x" + cmdId.toString(16).padStart(2, "0"),
);
try {
if (cmdId === 0x0a) {
const p = decodePermit2(inputs[i]);
// A permit states both halves itself, so it may replace an
// input side an earlier hop established without breaking
// the invariant.
if (p) setInput(p.token, p.amount);
}
if (cmdId === 0x0e) {
const b = decodeBalanceCheck(inputs[i]);
if (b) setOutput(b.token, b.minBalance);
}
if (cmdId === 0x00) {
const s = decodeV3SwapExactIn(inputs[i]);
if (s) {
setInputOnce(s.tokenIn, s.amountIn);
// Always update output: in multi-step swaps (V3 → V4),
// the last swap step determines the final output token
// and minimum received amount.
setOutput(s.tokenOut, s.amountOutMin);
}
}
if (cmdId === 0x08) {
const s = decodeV2SwapExactIn(inputs[i]);
if (s) {
setInputOnce(s.tokenIn, s.amountIn);
setOutput(s.tokenOut, s.amountOutMin);
}
}
if (cmdId === 0x0b) {
const w = decodeWrapEth(inputs[i]);
if (w) {
setInputOnce(
"0x0000000000000000000000000000000000000000",
w.amount,
);
}
}
if (cmdId === 0x10) {
const v4 = decodeV4Swap(inputs[i]);
if (v4) {
setInputOnce(v4.tokenIn, v4.amountIn);
// Always update output: last swap step wins. A step
// that carries the Min. received figure but decoded no
// output currency makes the output *undetermined* — it
// is neither ETH nor whatever an earlier step named,
// and that figure is no longer counted in that token.
// Equally, a step that names an output currency but no
// minimum leaves Min. received unstated rather than
// keeping an earlier step's figure beside the new
// token. setOutput() is both rules; a step that states
// neither half leaves the output alone.
setOutput(v4.tokenOut, v4.amountOutMin);
}
}
if (cmdId === 0x0c) {
hasUnwrapWeth = true;
}
} catch {
// Skip commands we can't decode
}
}
// Resolve token info. A null token on either side means the calldata
// named no currency for it; tokenInfo() refuses rather than calling it
// ETH. UNWRAP_WETH is the one output that is ETH without a currency to
// decode, and it is answered here rather than left to that rule.
const inInfo = tokenInfo(inputToken, sources);
const outInfo = hasUnwrapWeth
? { symbol: "ETH", decimals: 18, address: null }
: tokenInfo(outputToken, sources);
const inSymbol = inInfo.symbol;
const outSymbol = outInfo.symbol;
const name =
inSymbol && outSymbol
? "Swap " + inSymbol + " \u2192 " + outSymbol
: "Uniswap Swap";
const details = [];
details.push({
label: "Protocol",
value: "Uniswap Universal Router",
address: toAddress,
});
if (present(inputToken) && present(inInfo.address)) {
const label = inSymbol
? inSymbol + " (" + inputToken + ")"
: inputToken;
details.push({
label: "Token In",
value: label,
address: inputToken,
isToken: true,
});
} else if (inSymbol === "ETH") {
details.push({ label: "Token In", value: "ETH (native)" });
} else {
// Nothing established the input token, so the line says that
// rather than going missing or naming a token by default. Same
// wording as the Token Out refusal below: the two sides of this
// screen must not describe the same condition in two ways.
details.push({ label: "Token In", value: UNNAMED_CURRENCY });
}
if (present(inputAmount)) {
// Two amounts need no scale to describe and are named rather than
// formatted: V4's open delta, which is not a quantity at all (see
// OPEN_DELTA), and an unbounded permit. The open-delta test comes
// first — the sentinel is not a bigint and cannot be compared with
// one.
let amount;
if (inputAmount === OPEN_DELTA) {
amount = { raw: OPEN_DELTA_AMOUNT, display: OPEN_DELTA_AMOUNT };
} else if (inputAmount >= MAX_UINT160) {
amount = { raw: "Unlimited", display: "Unlimited" };
} else {
amount = amountText(inputAmount, inInfo);
}
details.push({
label: "Amount",
value: amount.display,
rawValue: amount.raw,
});
}
// Keyed on the address, not the symbol: a token absent from the
// bundled list has no symbol, and gating the line on one dropped it
// entirely, leaving a Min. received figure with nothing saying what is
// being received. The Token In line above already falls back to the
// address; this does the same.
if (present(outInfo.address)) {
const label = outSymbol
? outSymbol + " (" + outInfo.address + ")"
: outInfo.address;
details.push({
label: "Token Out",
value: label,
address: outInfo.address,
isToken: true,
});
} else if (outSymbol) {
details.push({ label: "Token Out", value: outSymbol });
} else {
// Nothing established the output token, so the line says that
// rather than going missing or naming a token by default, and a
// Min. received figure below it is never attached to a token the
// calldata did not state.
details.push({ label: "Token Out", value: UNNAMED_CURRENCY });
}
if (present(minOutput)) {
// A zero floor is the one case the user most needs stated: the
// swap guarantees nothing back. It is said in words, in the same
// register as UNNAMED_CURRENCY, because "0.0000 WETH" reads as an
// artifact of the four-decimal rule rather than as "this may
// return nothing" — and because it is true at every scale, so it
// holds even when the output token's decimals are unknown.
details.push({
label: "Min. received",
value:
minOutput === 0n
? NO_MINIMUM
: amountText(minOutput, outInfo).display,
});
}
details.push({ label: "Steps", value: commandNames.join(" \u2192 ") });
const deadlineDate = new Date(Number(deadline) * 1000);
details.push({
label: "Deadline",
value: deadlineDate.toISOString().replace("T", " ").slice(0, 19),
});
return {
name,
description: "Swap via Uniswap Universal Router",
details,
};
} catch {
return null;
}
}
module.exports = { decode };