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@0x/contracts-erc20: Switch LibERC20Token.approveIfBelowMax() to LibERC20Token.approveIfBelow().

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`@0x/contracts-asset-proxy`: Use `LibERC20Token.approveIfBelow()` for bridge approvals.
This commit is contained in:
Lawrence Forman 2020-03-04 21:32:47 -05:00
parent 3f51b9322f
commit c3d4c13936
7 changed files with 30 additions and 16 deletions
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2
contracts/asset-proxy/CHANGELOG.json
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@ -3,7 +3,7 @@
"version": "3.3.0",
"changes": [
{
"note": "Use `approveIfBelowMax()` in DEX bridges for for approvals.",
"note": "Use `LibERC20Token.approveIfBelow()` in DEX bridges for for approvals.",
"pr": 2512
},
{

4
contracts/asset-proxy/contracts/src/bridges/CurveBridge.sol
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@ -67,9 +67,9 @@ contract CurveBridge is
address fromTokenAddress = ICurve(data.curveAddress).underlying_coins(data.fromCoinIdx);
require(toTokenAddress != fromTokenAddress, "CurveBridge/INVALID_PAIR");
// Grant an allowance to the exchange to spend `fromTokenAddress` token.
LibERC20Token.approveIfBelowMax(fromTokenAddress, data.curveAddress);
uint256 fromTokenBalance = IERC20Token(fromTokenAddress).balanceOf(address(this));
// Grant an allowance to the exchange to spend `fromTokenAddress` token.
LibERC20Token.approveIfBelow(fromTokenAddress, data.curveAddress, fromTokenBalance);
// Try to sell all of this contract's `fromTokenAddress` token balance.
if (data.version == 0) {

5
contracts/asset-proxy/contracts/src/bridges/Eth2DaiBridge.sol
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@ -57,10 +57,9 @@ contract Eth2DaiBridge is
(address fromTokenAddress) = abi.decode(bridgeData, (address));
IEth2Dai exchange = IEth2Dai(_getEth2DaiAddress());
// Grant an allowance to the exchange to spend `fromTokenAddress` token.
LibERC20Token.approveIfBelowMax(fromTokenAddress, address(exchange));
uint256 fromTokenBalance = IERC20Token(fromTokenAddress).balanceOf(address(this));
// Grant an allowance to the exchange to spend `fromTokenAddress` token.
LibERC20Token.approveIfBelow(fromTokenAddress, address(exchange), fromTokenBalance);
// Try to sell all of this contract's `fromTokenAddress` token balance.
uint256 boughtAmount = exchange.sellAllAmount(

6
contracts/asset-proxy/contracts/src/bridges/KyberBridge.sol
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@ -110,7 +110,11 @@ contract KyberBridge is
} else if (state.fromTokenAddress != address(state.weth)) {
// If the input token is not WETH, grant an allowance to the exchange
// to spend them.
LibERC20Token.approveIfBelowMax(state.fromTokenAddress, address(state.kyber));
LibERC20Token.approveIfBelow(
state.fromTokenAddress,
address(state.kyber),
state.fromTokenBalance
);
} else {
// If the input token is WETH, unwrap it and attach it to the call.
state.fromTokenAddress = KYBER_ETH_ADDRESS;

17
contracts/asset-proxy/contracts/src/bridges/UniswapBridge.sol
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@ -110,7 +110,7 @@ contract UniswapBridge is
// Convert from a token to WETH.
} else if (toTokenAddress == address(state.weth)) {
// Grant the exchange an allowance.
_grantExchangeAllowance(state.exchange, fromTokenAddress);
_grantExchangeAllowance(state.exchange, fromTokenAddress, state.fromTokenBalance);
// Buy as much ETH with `fromTokenAddress` token as possible.
state.boughtAmount = state.exchange.tokenToEthSwapInput(
// Sell all tokens we hold.
@ -128,7 +128,7 @@ contract UniswapBridge is
// Convert from one token to another.
} else {
// Grant the exchange an allowance.
_grantExchangeAllowance(state.exchange, fromTokenAddress);
_grantExchangeAllowance(state.exchange, fromTokenAddress, state.fromTokenBalance);
// Buy as much `toTokenAddress` token with `fromTokenAddress` token
// and transfer it to `to`.
state.boughtAmount = state.exchange.tokenToTokenTransferInput(
@ -177,10 +177,19 @@ contract UniswapBridge is
/// on behalf of this contract.
/// @param exchange The Uniswap token exchange.
/// @param tokenAddress The token address for the exchange.
function _grantExchangeAllowance(IUniswapExchange exchange, address tokenAddress)
/// @param minimumAllowance The minimum necessary allowance.
function _grantExchangeAllowance(
IUniswapExchange exchange,
address tokenAddress,
uint256 minimumAllowance
)
private
{
LibERC20Token.approveIfBelowMax(tokenAddress, address(exchange));
LibERC20Token.approveIfBelow(
tokenAddress,
address(exchange),
minimumAllowance
);
}
/// @dev Retrieves the uniswap exchange for a given token pair.

2
contracts/erc20/CHANGELOG.json
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@ -3,7 +3,7 @@
"version": "3.2.0",
"changes": [
{
"note": "Add `LibERC20Token.approveIfBelowMax()`",
"note": "Add `LibERC20Token.approveIfBelow()`",
"pr": 2512
}
]

10
contracts/erc20/contracts/src/LibERC20Token.sol
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@ -48,18 +48,20 @@ library LibERC20Token {
}
/// @dev Calls `IERC20Token(token).approve()` and sets the allowance to the
/// maximum if the current approval is not already set to the maximum.
/// maximum if the current approval is not already >= an amount.
/// Reverts if `false` is returned or if the return
/// data length is nonzero and not 32 bytes.
/// @param token The address of the token contract.
/// @param spender The address that receives an allowance.
function approveIfBelowMax(
/// @param amount The minimum allowance needed.
function approveIfBelow(
address token,
address spender
address spender,
uint256 amount
)
internal
{
if (IERC20Token(token).allowance(address(this), spender) != uint256(-1)) {
if (IERC20Token(token).allowance(address(this), spender) < amount) {
approve(token, spender, uint256(-1));
}
}