@@ -3,141 +3,104 @@ pragma solidity ^0.5.16;
33import "./CErc20.sol " ;
44import "./CToken.sol " ;
55import "./PriceOracle.sol " ;
6- import "./Comptroller.sol " ;
7- import "./SafeMath.sol " ;
86
97interface V1PriceOracleInterface {
108 function assetPrices (address asset ) external view returns (uint );
119}
1210
1311contract PriceOracleProxy is PriceOracle {
14- using SafeMath for uint256 ;
12+ /// @notice Indicator that this is a PriceOracle contract (for inspection)
13+ bool public constant isPriceOracle = true ;
1514
16- /**
17- * @notice The v1 price oracle, which will continue to serve prices for v1 assets
18- */
15+ /// @notice The v1 price oracle, which will continue to serve prices for v1 assets
1916 V1PriceOracleInterface public v1PriceOracle;
2017
21- /**
22- * @notice The comptroller which is used to white-list assets the proxy will price
23- * @dev Assets which are not white-listed will not be priced, to defend against abuse
24- */
25- Comptroller public comptroller;
18+ /// @notice Address of the guardian, which may set the SAI price once
19+ address public guardian;
2620
27- /**
28- * @notice address of the cEther contract, which has a constant price
29- */
21+ /// @notice Address of the cEther contract, which has a constant price
3022 address public cEthAddress;
3123
32- /**
33- * @notice address of the cUSDC contract, which we hand pick a key for
34- */
24+ /// @notice Address of the cUSDC contract, which we hand pick a key for
3525 address public cUsdcAddress;
3626
37- /**
38- * @notice address of the cSAI contract, which we hand pick a key for
39- */
27+ /// @notice Address of the cSAI contract, which we hand pick a key for
4028 address public cSaiAddress;
4129
42- /**
43- * @notice address of the cDAI contract, which we peg to the SAI price
44- */
30+ /// @notice Address of the cDAI contract, which we hand pick a key for
4531 address public cDaiAddress;
4632
47- /**
48- * @notice address of the USDC contract, which we hand pick a key for
49- */
50- address constant usdcOracleKey = address (1 );
51-
52- /**
53- * @notice address of the SAI contract, which we hand pick a key for
54- */
55- address constant saiOracleKey = address (2 );
33+ /// @notice Handpicked key for USDC
34+ address public constant usdcOracleKey = address (1 );
5635
57- /**
58- * @notice address of the asset which contains the USD/ETH price from Maker
59- */
60- address public makerUsdOracleKey;
36+ /// @notice Handpicked key for DAI
37+ address public constant daiOracleKey = address (2 );
6138
62- /**
63- * @notice Indicator that this is a PriceOracle contract (for inspection)
64- */
65- bool public constant isPriceOracle = true ;
39+ /// @notice Frozen SAI price (or 0 if not set yet)
40+ uint public saiPrice;
6641
6742 /**
68- * @param comptroller_ The address of the comptroller , which will be consulted for market listing status
43+ * @param guardian_ The address of the guardian , which may set the SAI price once
6944 * @param v1PriceOracle_ The address of the v1 price oracle, which will continue to operate and hold prices for collateral assets
7045 * @param cEthAddress_ The address of cETH, which will return a constant 1e18, since all prices relative to ether
7146 * @param cUsdcAddress_ The address of cUSDC, which will be read from a special oracle key
72- * @param cSaiAddress_ The address of cSAI, which will be read from a special oracle key
73- * @param cDaiAddress_ The address of cDAI, which will be pegged to the SAI price
47+ * @param cSaiAddress_ The address of cSAI, which will be read directly from storage
48+ * @param cDaiAddress_ The address of cDAI, which will be read from a special oracle key
7449 */
75- constructor (address comptroller_ ,
50+ constructor (address guardian_ ,
7651 address v1PriceOracle_ ,
7752 address cEthAddress_ ,
7853 address cUsdcAddress_ ,
7954 address cSaiAddress_ ,
8055 address cDaiAddress_ ) public {
81- comptroller = Comptroller (comptroller_) ;
56+ guardian = guardian_ ;
8257 v1PriceOracle = V1PriceOracleInterface (v1PriceOracle_);
8358
8459 cEthAddress = cEthAddress_;
8560 cUsdcAddress = cUsdcAddress_;
8661 cSaiAddress = cSaiAddress_;
8762 cDaiAddress = cDaiAddress_;
88-
89- if (cSaiAddress_ != address (0 )) {
90- makerUsdOracleKey = CErc20 (cSaiAddress_).underlying ();
91- }
9263 }
9364
9465 /**
9566 * @notice Get the underlying price of a listed cToken asset
9667 * @param cToken The cToken to get the underlying price of
97- * @return The underlying asset price mantissa (scaled by 1e18).
98- * Zero means the price is unavailable.
68+ * @return The underlying asset price mantissa (scaled by 1e18)
9969 */
10070 function getUnderlyingPrice (CToken cToken ) public view returns (uint ) {
10171 address cTokenAddress = address (cToken);
102- (bool isListed , ) = comptroller.markets (cTokenAddress);
103-
104- if (! isListed) {
105- // not white-listed, worthless
106- return 0 ;
107- }
10872
10973 if (cTokenAddress == cEthAddress) {
11074 // ether always worth 1
11175 return 1e18 ;
11276 }
11377
11478 if (cTokenAddress == cUsdcAddress) {
115- // we assume USDC/USD = 1, and let DAI/ETH float based on the DAI/USDC ratio
116- // use the maker usd price (for a token w/ 6 decimals)
117- return v1PriceOracle.assetPrices (makerUsdOracleKey).mul (1e12 ); // 1e(18 - 6)
79+ return v1PriceOracle.assetPrices (usdcOracleKey);
11880 }
11981
120- if (cTokenAddress == cSaiAddress || cTokenAddress == cDaiAddress) {
121- // check and bound the DAI/USDC posted price ratio
122- // and use that to scale the maker price (for a token w/ 18 decimals)
123- uint makerUsdPrice = v1PriceOracle.assetPrices (makerUsdOracleKey);
124- uint postedUsdcPrice = v1PriceOracle.assetPrices (usdcOracleKey);
125- uint postedScaledDaiPrice = v1PriceOracle.assetPrices (saiOracleKey).mul (1e12 );
126- uint daiUsdcRatio = postedScaledDaiPrice.mul (1e18 ).div (postedUsdcPrice);
127-
128- if (daiUsdcRatio < 0.95e18 ) {
129- return makerUsdPrice.mul (0.95e18 ).div (1e18 );
130- }
131-
132- if (daiUsdcRatio > 1.05e18 ) {
133- return makerUsdPrice.mul (1.05e18 ).div (1e18 );
134- }
82+ if (cTokenAddress == cDaiAddress) {
83+ return v1PriceOracle.assetPrices (daiOracleKey);
84+ }
13585
136- return makerUsdPrice.mul (daiUsdcRatio).div (1e18 );
86+ if (cTokenAddress == cSaiAddress) {
87+ // use the frozen SAI price if set, otherwise use the DAI price
88+ return saiPrice > 0 ? saiPrice : v1PriceOracle.assetPrices (daiOracleKey);
13789 }
13890
13991 // otherwise just read from v1 oracle
14092 address underlying = CErc20 (cTokenAddress).underlying ();
14193 return v1PriceOracle.assetPrices (underlying);
14294 }
95+
96+ /**
97+ * @notice Set the price of SAI, permanently
98+ * @param price The price for SAI
99+ */
100+ function setSaiPrice (uint price ) public {
101+ require (msg .sender == guardian, "only guardian may set the SAI price " );
102+ require (saiPrice == 0 , "SAI price may only be set once " );
103+ require (price < 0.1e18 , "SAI price must be < 0.1 ETH " );
104+ saiPrice = price;
105+ }
143106}
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