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Merge pull request #1384 from o1-labs/feature/token-contract
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General-purpose token contract
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@mitschabaude
mitschabaude authored Feb 12, 2024
2 parents 8624f44 + b5ef432 commit baac0cb
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5 changes: 4 additions & 1 deletion CHANGELOG.md
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Expand Up @@ -21,7 +21,10 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm

- `MerkleList<T>` to enable provable operations on a dynamically-sized list https://github.com/o1-labs/o1js/pull/1398
- including `MerkleListIterator<T>` to iterate over a merkle list
- `TokenAccountUpdateIterator`, a primitive for token contracts to iterate over all token account updates in a transaction. https://github.com/o1-labs/o1js/pull/1398
- `TokenContract`, a new base smart contract class for token contracts https://github.com/o1-labs/o1js/pull/1384
- Usage example: `https://github.com/o1-labs/o1js/blob/main/src/lib/mina/token/token-contract.unit-test.ts`
- `TokenAccountUpdateIterator`, a primitive to iterate over all token account updates in a transaction https://github.com/o1-labs/o1js/pull/1398
- this is used to implement `TokenContract` under the hood

## [0.16.0](https://github.com/o1-labs/o1js/compare/e5d1e0f...834a44002)

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7 changes: 4 additions & 3 deletions src/examples/zkapps/dex/dex-with-actions.ts
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Expand Up @@ -22,7 +22,8 @@ import {
state,
} from 'o1js';

import { TokenContract, randomAccounts } from './dex.js';
import { randomAccounts } from './dex.js';
import { TrivialCoin as TokenContract } from './erc20.js';

export { Dex, DexTokenHolder, addresses, getTokenBalances, keys, tokenIds };

Expand Down Expand Up @@ -188,7 +189,7 @@ class Dex extends SmartContract {
let tokenY = new TokenContract(this.tokenY);
let dexY = new DexTokenHolder(this.address, tokenY.token.id);
let dy = dexY.swap(this.sender, dx, this.tokenX);
tokenY.approveUpdateAndSend(dexY.self, this.sender, dy);
tokenY.transfer(dexY.self, this.sender, dy);
return dy;
}

Expand All @@ -206,7 +207,7 @@ class Dex extends SmartContract {
let tokenX = new TokenContract(this.tokenX);
let dexX = new DexTokenHolder(this.address, tokenX.token.id);
let dx = dexX.swap(this.sender, dy, this.tokenY);
tokenX.approveUpdateAndSend(dexX.self, this.sender, dx);
tokenX.transfer(dexX.self, this.sender, dx);
return dx;
}

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124 changes: 21 additions & 103 deletions src/examples/zkapps/dex/dex.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -2,11 +2,7 @@ import {
Account,
AccountUpdate,
Bool,
DeployArgs,
Field,
Int64,
Mina,
Permissions,
PrivateKey,
Provable,
PublicKey,
Expand All @@ -16,9 +12,10 @@ import {
TokenId,
UInt32,
UInt64,
VerificationKey,
method,
state,
TokenContract as BaseTokenContract,
AccountUpdateForest,
} from 'o1js';

export { TokenContract, addresses, createDex, keys, randomAccounts, tokenIds };
Expand Down Expand Up @@ -56,15 +53,13 @@ function createDex({
let tokenY = new TokenContract(this.tokenY);

// get balances of X and Y token
// TODO: this creates extra account updates. we need to reuse these by passing them to or returning them from transfer()
// but for that, we need the @method argument generalization
let dexXUpdate = AccountUpdate.create(this.address, tokenX.token.id);
let dexXBalance = dexXUpdate.account.balance.getAndRequireEquals();

let dexYUpdate = AccountUpdate.create(this.address, tokenY.token.id);
let dexYBalance = dexYUpdate.account.balance.getAndRequireEquals();

// // assert dy === [dx * y/x], or x === 0
// assert dy === [dx * y/x], or x === 0
let isXZero = dexXBalance.equals(UInt64.zero);
let xSafe = Provable.if(isXZero, UInt64.one, dexXBalance);
let isDyCorrect = dy.equals(dx.mul(dexYBalance).div(xSafe));
Expand All @@ -73,7 +68,7 @@ function createDex({
tokenX.transfer(user, dexXUpdate, dx);
tokenY.transfer(user, dexYUpdate, dy);

// calculate liquidity token output simply as dl = dx + dx
// calculate liquidity token output simply as dl = dx + dy
// => maintains ratio x/l, y/l
let dl = dy.add(dx);
let userUpdate = this.token.mint({ address: user, amount: dl });
Expand Down Expand Up @@ -144,7 +139,7 @@ function createDex({
let dexX = new DexTokenHolder(this.address, tokenX.token.id);
let dxdy = dexX.redeemLiquidity(this.sender, dl, this.tokenY);
let dx = dxdy[0];
tokenX.approveUpdateAndSend(dexX.self, this.sender, dx);
tokenX.transfer(dexX.self, this.sender, dx);
return dxdy;
}

Expand All @@ -159,7 +154,7 @@ function createDex({
let tokenY = new TokenContract(this.tokenY);
let dexY = new DexTokenHolder(this.address, tokenY.token.id);
let dy = dexY.swap(this.sender, dx, this.tokenX);
tokenY.approveUpdateAndSend(dexY.self, this.sender, dy);
tokenY.transfer(dexY.self, this.sender, dy);
return dy;
}

Expand All @@ -174,7 +169,7 @@ function createDex({
let tokenX = new TokenContract(this.tokenX);
let dexX = new DexTokenHolder(this.address, tokenX.token.id);
let dx = dexX.swap(this.sender, dy, this.tokenY);
tokenX.approveUpdateAndSend(dexX.self, this.sender, dx);
tokenX.transfer(dexX.self, this.sender, dx);
return dx;
}

Expand Down Expand Up @@ -208,7 +203,7 @@ function createDex({
let tokenY = new TokenContract(this.tokenY);
let dexY = new ModifiedDexTokenHolder(this.address, tokenY.token.id);
let dy = dexY.swap(this.sender, dx, this.tokenX);
tokenY.approveUpdateAndSend(dexY.self, this.sender, dy);
tokenY.transfer(dexY.self, this.sender, dy);
return dy;
}
}
Expand Down Expand Up @@ -250,7 +245,7 @@ function createDex({
let result = dexY.redeemLiquidityPartial(user, dl);
let l = result[0];
let dy = result[1];
tokenY.approveUpdateAndSend(dexY.self, user, dy);
tokenY.transfer(dexY.self, user, dy);

// in return for dl, we give back dx, the X token part
let x = this.account.balance.get();
Expand All @@ -272,11 +267,11 @@ function createDex({
let dx = otherTokenAmount;
let tokenX = new TokenContract(otherTokenAddress);
// get balances
let x = tokenX.getBalance(this.address);
let y = this.account.balance.get();
this.account.balance.requireEquals(y);
let dexX = AccountUpdate.create(this.address, tokenX.token.id);
let x = dexX.account.balance.getAndRequireEquals();
let y = this.account.balance.getAndRequireEquals();
// send x from user to us (i.e., to the same address as this but with the other token)
tokenX.transfer(user, this.address, dx);
tokenX.transfer(user, dexX, dx);
// compute and send dy
let dy = y.mul(dx).div(x.add(dx));
// just subtract dy balance and let adding balance be handled one level higher
Expand All @@ -296,10 +291,12 @@ function createDex({
): UInt64 {
let dx = otherTokenAmount;
let tokenX = new TokenContract(otherTokenAddress);
let x = tokenX.getBalance(this.address);
// get balances
let dexX = AccountUpdate.create(this.address, tokenX.token.id);
let x = dexX.account.balance.getAndRequireEquals();
let y = this.account.balance.get();
this.account.balance.requireEquals(y);
tokenX.transfer(user, this.address, dx);
tokenX.transfer(user, dexX, dx);

// this formula has been changed - we just give the user an additional 15 token
let dy = y.mul(dx).div(x.add(dx)).add(15);
Expand Down Expand Up @@ -371,14 +368,7 @@ function createDex({
/**
* Simple token with API flexible enough to handle all our use cases
*/
class TokenContract extends SmartContract {
deploy(args?: DeployArgs) {
super.deploy(args);
this.account.permissions.set({
...Permissions.default(),
access: Permissions.proofOrSignature(),
});
}
class TokenContract extends BaseTokenContract {
@method init() {
super.init();
// mint the entire supply to the token account with the same address as this contract
Expand Down Expand Up @@ -413,68 +403,9 @@ class TokenContract extends SmartContract {
this.balance.subInPlace(Mina.getNetworkConstants().accountCreationFee);
}

// this is a very standardized deploy method. instead, we could also take the account update from a callback
// => need callbacks for signatures
@method deployZkapp(address: PublicKey, verificationKey: VerificationKey) {
let tokenId = this.token.id;
let zkapp = AccountUpdate.create(address, tokenId);
zkapp.account.permissions.set(Permissions.default());
zkapp.account.verificationKey.set(verificationKey);
zkapp.requireSignature();
}

@method approveUpdate(zkappUpdate: AccountUpdate) {
this.approve(zkappUpdate);
let balanceChange = Int64.fromObject(zkappUpdate.body.balanceChange);
balanceChange.assertEquals(Int64.from(0));
}

// FIXME: remove this
@method approveAny(zkappUpdate: AccountUpdate) {
this.approve(zkappUpdate, AccountUpdate.Layout.AnyChildren);
}

// let a zkapp send tokens to someone, provided the token supply stays constant
@method approveUpdateAndSend(
zkappUpdate: AccountUpdate,
to: PublicKey,
amount: UInt64
) {
// approve a layout of two grandchildren, both of which can't inherit the token permission
let { StaticChildren, AnyChildren } = AccountUpdate.Layout;
this.approve(zkappUpdate, StaticChildren(AnyChildren, AnyChildren));
zkappUpdate.body.mayUseToken.parentsOwnToken.assertTrue();
let [grandchild1, grandchild2] = zkappUpdate.children.accountUpdates;
grandchild1.body.mayUseToken.inheritFromParent.assertFalse();
grandchild2.body.mayUseToken.inheritFromParent.assertFalse();

// see if balance change cancels the amount sent
let balanceChange = Int64.fromObject(zkappUpdate.body.balanceChange);
balanceChange.assertEquals(Int64.from(amount).neg());
// add same amount of tokens to the receiving address
this.token.mint({ address: to, amount });
}

transfer(from: PublicKey, to: PublicKey | AccountUpdate, amount: UInt64) {
if (to instanceof PublicKey)
return this.transferToAddress(from, to, amount);
if (to instanceof AccountUpdate)
return this.transferToUpdate(from, to, amount);
}
@method transferToAddress(from: PublicKey, to: PublicKey, value: UInt64) {
this.token.send({ from, to, amount: value });
}
@method transferToUpdate(from: PublicKey, to: AccountUpdate, value: UInt64) {
this.token.send({ from, to, amount: value });
}

@method getBalance(publicKey: PublicKey): UInt64 {
let accountUpdate = AccountUpdate.create(publicKey, this.token.id);
let balance = accountUpdate.account.balance.get();
accountUpdate.account.balance.requireEquals(
accountUpdate.account.balance.get()
);
return balance;
@method
approveBase(forest: AccountUpdateForest) {
this.checkZeroBalanceChange(forest);
}
}

Expand Down Expand Up @@ -502,19 +433,6 @@ let tokenIds = {
lqXY: TokenId.derive(addresses.dex),
};

/**
* Sum of balances of the account update and all its descendants
*/
function balanceSum(accountUpdate: AccountUpdate, tokenId: Field) {
let myTokenId = accountUpdate.body.tokenId;
let myBalance = Int64.fromObject(accountUpdate.body.balanceChange);
let balance = Provable.if(myTokenId.equals(tokenId), myBalance, Int64.zero);
for (let child of accountUpdate.children.accountUpdates) {
balance = balance.add(balanceSum(child, tokenId));
}
return balance;
}

/**
* Predefined accounts keys, labeled by the input strings. Useful for testing/debugging with consistent keys.
*/
Expand Down
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