aave-protocol-v2/contracts/misc/AaveOracle.sol

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// SPDX-License-Identifier: agpl-3.0
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pragma solidity 0.6.12;
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import {Ownable} from '../dependencies/openzeppelin/contracts/Ownable.sol';
import {IERC20} from '../dependencies/openzeppelin/contracts/IERC20.sol';
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import {IPriceOracleGetter} from '../interfaces/IPriceOracleGetter.sol';
import {IChainlinkAggregator} from '../interfaces/IChainlinkAggregator.sol';
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import {SafeERC20} from '../dependencies/openzeppelin/contracts/SafeERC20.sol';
/// @title AaveOracle
/// @author Aave
/// @notice Proxy smart contract to get the price of an asset from a price source, with Chainlink Aggregator
/// smart contracts as primary option
/// - If the returned price by a Chainlink aggregator is <= 0, the call is forwarded to a fallbackOracle
/// - Owned by the Aave governance system, allowed to add sources for assets, replace them
/// and change the fallbackOracle
contract AaveOracle is IPriceOracleGetter, Ownable {
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using SafeERC20 for IERC20;
event WethSet(address indexed weth);
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event AssetSourceUpdated(address indexed asset, address indexed source);
event FallbackOracleUpdated(address indexed fallbackOracle);
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mapping(address => IChainlinkAggregator) private assetsSources;
IPriceOracleGetter private _fallbackOracle;
address public immutable WETH;
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/// @notice Constructor
/// @param assets The addresses of the assets
/// @param sources The address of the source of each asset
/// @param fallbackOracle The address of the fallback oracle to use if the data of an
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/// aggregator is not consistent
constructor(
address[] memory assets,
address[] memory sources,
address fallbackOracle,
address weth
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) public {
_setFallbackOracle(fallbackOracle);
_setAssetsSources(assets, sources);
WETH = weth;
emit WethSet(weth);
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}
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/// @notice External function called by the Aave governance to set or replace sources of assets
/// @param assets The addresses of the assets
/// @param sources The address of the source of each asset
function setAssetSources(address[] calldata assets, address[] calldata sources)
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external
onlyOwner
{
_setAssetsSources(assets, sources);
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}
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/// @notice Sets the fallbackOracle
/// - Callable only by the Aave governance
/// @param fallbackOracle The address of the fallbackOracle
function setFallbackOracle(address fallbackOracle) external onlyOwner {
_setFallbackOracle(fallbackOracle);
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}
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/// @notice Internal function to set the sources for each asset
/// @param assets The addresses of the assets
/// @param sources The address of the source of each asset
function _setAssetsSources(address[] memory assets, address[] memory sources) internal {
require(assets.length == sources.length, 'INCONSISTENT_PARAMS_LENGTH');
for (uint256 i = 0; i < assets.length; i++) {
assetsSources[assets[i]] = IChainlinkAggregator(sources[i]);
emit AssetSourceUpdated(assets[i], sources[i]);
}
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}
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/// @notice Internal function to set the fallbackOracle
/// @param fallbackOracle The address of the fallbackOracle
function _setFallbackOracle(address fallbackOracle) internal {
_fallbackOracle = IPriceOracleGetter(fallbackOracle);
emit FallbackOracleUpdated(fallbackOracle);
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}
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/// @notice Gets an asset price by address
/// @param asset The asset address
function getAssetPrice(address asset) public view override returns (uint256) {
IChainlinkAggregator source = assetsSources[asset];
if (asset == WETH) {
return 1 ether;
} else if (address(source) == address(0)) {
return _fallbackOracle.getAssetPrice(asset);
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} else {
int256 price = IChainlinkAggregator(source).latestAnswer();
if (price > 0) {
return uint256(price);
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} else {
return _fallbackOracle.getAssetPrice(asset);
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}
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}
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}
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/// @notice Gets a list of prices from a list of assets addresses
/// @param assets The list of assets addresses
function getAssetsPrices(address[] calldata assets) external view returns (uint256[] memory) {
uint256[] memory prices = new uint256[](assets.length);
for (uint256 i = 0; i < assets.length; i++) {
prices[i] = getAssetPrice(assets[i]);
}
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return prices;
}
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/// @notice Gets the address of the source for an asset address
/// @param asset The address of the asset
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/// @return address The address of the source
function getSourceOfAsset(address asset) external view returns (address) {
return address(assetsSources[asset]);
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}
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/// @notice Gets the address of the fallback oracle
/// @return address The addres of the fallback oracle
function getFallbackOracle() external view returns (address) {
return address(_fallbackOracle);
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}
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}