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@0x:contracts-staking Added WETH support to MixinExchangeFees

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This commit is contained in:
Alex Towle 2019-09-03 18:55:09 -07:00
parent 3a503c61b3
commit 494dc475c1
7 changed files with 103 additions and 21 deletions
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59
contracts/staking/contracts/src/fees/MixinExchangeFees.sol
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@ -19,6 +19,9 @@
pragma solidity ^0.5.9;
pragma experimental ABIEncoderV2;
import "@0x/contracts-asset-proxy/contracts/src/interfaces/IAssetData.sol";
import "@0x/contracts-asset-proxy/contracts/src/interfaces/IAssetProxy.sol";
import "@0x/contracts-erc20/contracts/src/interfaces/IEtherToken.sol";
import "@0x/contracts-utils/contracts/src/LibRichErrors.sol";
import "@0x/contracts-utils/contracts/src/LibSafeMath.sol";
import "../libs/LibStakingRichErrors.sol";
@ -80,10 +83,11 @@ contract MixinExchangeFees is
emit CobbDouglasAlphaChanged(numerator, denominator);
}
/// TODO(jalextowle): Add WETH to protocol fees. Should this be unwrapped?
/// @dev Pays a protocol fee in ETH.
/// @dev Pays a protocol fee in ETH or WETH.
/// Only a known 0x exchange can call this method. See (MixinExchangeManager).
/// @param makerAddress The address of the order's maker.
/// @param payerAddress The address of the protocol fee payer.
/// @param protocolFeePaid The protocol fee that should be paid.
function payProtocolFee(
address makerAddress,
// solhint-disable-next-line
@ -95,20 +99,39 @@ contract MixinExchangeFees is
payable
onlyExchange
{
uint256 amount = msg.value;
// Get the pool id of the maker address, and use this pool id to get the amount
// of fees collected during this epoch.
bytes32 poolId = getStakingPoolIdOfMaker(makerAddress);
if (poolId != NIL_POOL_ID) {
// There is a pool associated with `makerAddress`.
// TODO(dorothy-zbornak): When we have epoch locks on delegating, we could
// preclude pools that have no delegated stake, since they will never have
// stake in this epoch and are therefore not entitled to rewards.
uint256 _feesCollectedThisEpoch = protocolFeesThisEpochByPool[poolId];
protocolFeesThisEpochByPool[poolId] = _feesCollectedThisEpoch.safeAdd(amount);
if (msg.value == 0) {
// Transfer the protocol fee to this address.
erc20Proxy.transferFrom(
wethAssetData,
payerAddress,
address(this),
protocolFeePaid
);
// Update the amount of protocol fees paid to this pool this epoch.
protocolFeesThisEpochByPool[poolId] = _feesCollectedThisEpoch.safeAdd(protocolFeePaid);
} else if (msg.value == protocolFeePaid) {
// Update the amount of protocol fees paid to this pool this epoch.
protocolFeesThisEpochByPool[poolId] = _feesCollectedThisEpoch.safeAdd(protocolFeePaid);
} else {
// If the wrong message value was sent, revert with a rich error.
LibRichErrors.rrevert(LibStakingRichErrors.InvalidProtocolFeePaymentError(
protocolFeePaid,
msg.value
));
}
// If there were no fees collected prior to this payment, activate the pool that is being paid.
if (_feesCollectedThisEpoch == 0) {
activePoolsThisEpoch.push(poolId);
}
}
}
/// @dev Pays the rebates for to market making pool that was active this epoch,
/// then updates the epoch and other time-based periods via the scheduler (see MixinScheduler).
@ -181,7 +204,11 @@ contract MixinExchangeFees is
uint256 finalContractBalance
)
{
// initialize return values
// step 1/4 - withdraw the entire wrapper ether balance into this contract.
// WETH is unwrapped here to keep `payProtocolFee()` calls relatively cheap.
uint256 wethBalance = IEtherToken(WETH_ADDRESS).balanceOf(address(this));
IEtherToken(WETH_ADDRESS).withdraw(wethBalance);
totalActivePools = activePoolsThisEpoch.length;
totalFeesCollected = 0;
totalWeightedStake = 0;
@ -201,7 +228,7 @@ contract MixinExchangeFees is
);
}
// step 1/3 - compute stats for active maker pools
// step 2/4 - compute stats for active maker pools
IStructs.ActivePool[] memory activePools = new IStructs.ActivePool[](totalActivePools);
for (uint256 i = 0; i != totalActivePools; i++) {
bytes32 poolId = activePoolsThisEpoch[i];
@ -217,8 +244,9 @@ contract MixinExchangeFees is
);
// store pool stats
uint256 protocolFeeBalance = protocolFeesThisEpochByPool[poolId];
activePools[i].poolId = poolId;
activePools[i].feesCollected = protocolFeesThisEpochByPool[poolId];
activePools[i].feesCollected = protocolFeeBalance;
activePools[i].weightedStake = weightedStake;
activePools[i].delegatedStake = totalStakeDelegatedToPool;
@ -240,7 +268,7 @@ contract MixinExchangeFees is
);
}
// step 2/3 - record reward for each pool
// step 3/4 - record reward for each pool
for (uint256 i = 0; i != totalActivePools; i++) {
// compute reward using cobb-douglas formula
uint256 reward = _cobbDouglas(
@ -277,7 +305,7 @@ contract MixinExchangeFees is
}
activePoolsThisEpoch.length = 0;
// step 3/3 send total payout to vault
// step 4/4 send total payout to vault
// Sanity check rewards calculation
if (totalRewardsPaid > initialContractBalance) {
@ -289,6 +317,7 @@ contract MixinExchangeFees is
if (totalRewardsPaid > 0) {
_depositIntoStakingPoolRewardVault(totalRewardsPaid);
}
finalContractBalance = address(this).balance;
return (

11
contracts/staking/contracts/src/fees/MixinExchangeManager.sol
View File

@ -45,6 +45,17 @@ contract MixinExchangeManager is
_;
}
/// @dev Adds a new erc20 proxy.
/// @param erc20AssetProxy The asset proxy that will transfer erc20 tokens.
function addERC20AssetProxy(address erc20AssetProxy)
external
onlyOwner
{
// Update the erc20 asset proxy.
erc20Proxy = IAssetProxy(erc20AssetProxy);
emit ERC20AssetProxy(erc20AssetProxy);
}
/// @dev Adds a new exchange address
/// @param addr Address of exchange contract to add
function addExchangeAddress(address addr)

3
contracts/staking/contracts/src/immutable/MixinConstants.sol
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@ -43,4 +43,7 @@ contract MixinConstants is
uint64 constant internal INITIAL_TIMELOCK_PERIOD = INITIAL_EPOCH;
uint256 constant internal MIN_TOKEN_VALUE = 10**18;
// The address of the canonical WETH contract -- this will be used as an alternative to ether for paying protocol fees.
address constant internal WETH_ADDRESS = address(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2);
}

16
contracts/staking/contracts/src/immutable/MixinStorage.sol
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@ -18,6 +18,8 @@
pragma solidity ^0.5.9;
import "@0x/contracts-asset-proxy/contracts/src/interfaces/IAssetData.sol";
import "@0x/contracts-asset-proxy/contracts/src/interfaces/IAssetProxy.sol";
import "@0x/contracts-utils/contracts/src/Ownable.sol";
import "./MixinConstants.sol";
import "../interfaces/IZrxVault.sol";
@ -35,7 +37,19 @@ contract MixinStorage is
constructor()
public
Ownable()
{}
{
// Set the erc20 asset proxy data.
wethAssetData = abi.encodeWithSelector(
IAssetData(address(0)).ERC20Token.selector,
WETH_ADDRESS
);
}
// 0x ERC20 Proxy
IAssetProxy internal erc20Proxy;
// The asset data that should be sent to transfer weth
bytes internal wethAssetData;
// address of staking contract
address internal stakingContract;

6
contracts/staking/contracts/src/interfaces/IStakingEvents.sol
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@ -126,4 +126,10 @@ interface IStakingEvents {
event StakingPoolRewardVaultChanged(
address rewardVaultAddress
);
/// @dev Emitted by MixinExchangeManager when the erc20AssetProxy address changes.
/// @param erc20AddressProxy The new erc20 asset proxy address.
event ERC20AssetProxy(
address erc20AddressProxy
);
}

19
contracts/staking/contracts/src/libs/LibStakingRichErrors.sol
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@ -113,6 +113,10 @@ library LibStakingRichErrors {
POOL_IS_FULL
}
// bytes4(keccak256("InvalidProtocolFeePaymentError(uint256,uint256)"))
bytes4 internal constant INVALID_PROTOCOL_FEE_PAYMENT_ERROR_SELECTOR =
0x31d7a505;
// solhint-disable func-name-mixedcase
function MiscalculatedRewardsError(
uint256 totalRewardsPaid,
@ -359,6 +363,21 @@ library LibStakingRichErrors {
);
}
function InvalidProtocolFeePaymentError(
uint256 expectedProtocolFeePaid,
uint256 actualProtocolFeePaid
)
internal
pure
returns (bytes memory)
{
return abi.encodeWithSelector(
INVALID_PROTOCOL_FEE_PAYMENT_ERROR_SELECTOR,
expectedProtocolFeePaid,
actualProtocolFeePaid
);
}
function RewardVaultNotSetError()
internal
pure