crytotech / balancer-registry

Onchain Registry & Exchange Proxy

Registry.sol

Stores a registry of Balancer Pool addresses for a given token address pair. Pools can be sorted in order of liquidity and queried via view functions.

Fork of https://github.com/CryptoManiacsZone/BalancerRegistry

Adding Pools To Registry

addPoolPair(address pool, address token1, address token2)

Adds a single pool address for token pair.

addPools(address[] calldata pools, address token1, address token2)

Adds an array of pool addresses for token pair.

Sorting Pools

sortPools(address[] calldata tokens, uint256 lengthLimit)

Sorts pools in order of liquidity. lengthLimit can be used to limit the number of pools sorted.

sortPoolsWithPurge(address[] calldata tokens, uint256 lengthLimit)

Sorts pools in order of liquidity and removes any pools with <10% of total liquidity.

Retrieving Pools

getBestPools(address fromToken, address destToken)

Retrieve array of pool addresses for token pair. Ordered by liquidity if previously sorted. Max of 32 pools returned.

getBestPoolsWithLimit(address fromToken, address destToken, uint256 limit)

Retrieve array of pool addresses for token pair. Ordered by liquidity if previously sorted. Max of n pools returned where n=limit.

getPoolsWithLimit(address fromToken, address destToken, uint256 offset, uint256 limit)

Retrieve array of pool addresses using an offset starting position.

ExchangeProxy.sol

This contract includes swap forwarding proxy logic and on-chain smart order routing functionality.

batchSwap functions allows users to batch execute swaps recommended by off-chain SOR.

viewSplit functions query the Registry to provide best swap information using on-chain data.

smartSwap functions combine view and batch functionality to provide complete optimised on-chain swaps.

batchSwap functions

multihopBatchSwapExactIn(Swap[][] memory swapSequences, TokenInterface tokenIn, TokenInterface tokenOut, uint totalAmountIn, uint minTotalAmountOut) public payable

Execute multi-hop swaps returned from off-chain SOR for swapExactIn trade type.

multihopBatchSwapExactOut(Swap[][] memory swapSequences, TokenInterface tokenIn, TokenInterface tokenOut, uint maxTotalAmountIn) public payable

Execute multi-hop swaps returned from off-chain SOR for swapExactOut trade type.

batchSwapExactIn(Swap[] memory swaps, TokenInterface tokenIn, TokenInterface tokenOut, uint totalAmountIn, uint minTotalAmountOut) public payable

Execute single-hop swaps for swapExactIn trade type. Used for swaps returned from viewSplit function and legacy off-chain SOR.

batchSwapExactOut(Swap[] memory swaps, TokenInterface tokenIn, TokenInterface tokenOut, uint maxTotalAmountIn) public payable

Execute single-hop swaps for swapExactOut trade type. Used for swaps returned from viewSplit function and legacy off-chain SOR.

viewSplit functions

viewSplitExactIn(address tokenIn, address tokenOut, uint swapAmount, uint nPools)

View function that calculates most optimal swaps (exactIn swap type) across a max of nPools. Returns an array of Swaps and the total amount out for swap.

viewSplitExactOut(address tokenIn, address tokenOut, uint swapAmount, uint nPools)

View function that calculates most optimal swaps (exactOut swap type) across a max of nPools. Returns an array of Swaps and the total amount in for swap. (! Please be aware the return parameter "totalOutput" in the contract is a misnomer and actually represents totalInput !)

smartSwap functions

smartSwapExactIn(TokenInterface tokenIn, TokenInterface tokenOut, uint totalAmountIn, uint minTotalAmountOut, uint nPools) public payable

Calculates and executes most optimal swaps across a max of nPools for tokenIn > tokenOut swap with an input token amount = totalAmountIn.

smartSwapExactOut(TokenInterface tokenIn, TokenInterface tokenOut, uint totalAmountOut, uint maxTotalAmountIn, uint nPools) public payable

Calculates and executes most optimal swaps across a max of nPools for tokenIn > tokenOut swap with a desired output token amount = totalAmountOut.

Testing

To run tests:

$ npx buidler node
$ npx buidler test

Deploying

Deploy scripts:

Add .env variable to root and include: INFURA=your_api_key and KEYKOVAN/KEYRINKEBY/KEYMAIN=deploy_key

• Mainnet: $ npx buidler run --network main deploy-script-mainnet.js
• Kovan: $ npx buidler run --network kovan deploy-script-kovan.js
• Rinkeby: $ npx buidler run --network rinkeby deploy-script-rinkeby.js