import OracleInterface from 0xcec15c814971c1dc import OracleConfig from 0xcec15c814971c1dc import DelegatorManager from 0xd6f80565193ad727 import LiquidStakingConfig from 0xd6f80565193ad727 /// On-chain PriceOracle for stFlowToken/USD, which leverages on-chain PriceOracle for FlowToken/USD. /// It needs to be a whitelisted reader of Flow/USD PriceOracle. /// But no feeder is needed in this PriceOracle as stFlow/USD = Flow/USD x stFlow/Flow. pub contract PriceOracleStFlow: OracleInterface { /// The identifier of the token type, eg: stFlow/USD pub var _PriceIdentifier: String? /// Recommended path for PriceReader, users can manage resources by themselves pub var _PriceReaderStoragePath: StoragePath? /// Storage path of public interface resource pub let _OraclePublicStoragePath: StoragePath /// Storage path to store the PriceReader resource of the Flow/USD price feed pub let _FlowPriceReaderPath: StoragePath /// Address whitelist of readers access(self) let _ReaderWhiteList: {Address: Bool} /// Reserved parameter fields: {ParamName: Value} access(self) let _reservedFields: {String: AnyStruct} /// Events pub event MintPriceReader() pub event ConfigOracle(oldType: String?, newType: String, oldReaderStoragePath: StoragePath?, newReaderStoragePath: StoragePath) pub event AddReaderWhiteList(addr: Address) pub event DelReaderWhiteList(addr: Address) /// Oracle price reader, users need to save this resource in their local storage /// /// Only readers in the addr whitelist have permission to read prices /// Please do not share your PriceReader capability with others and take the responsibility of community governance. pub resource PriceReader { pub let _PriceIdentifier: String /// @Return the median price of stFlow/USD price feed, return 0.0 if there's no valid price data to provide pub fun getMedianPrice(): UFix64 { // If no this feed's PriceReader resource, or the reader is not in stFlow/USD feed's whitelist if self.owner == nil || PriceOracleStFlow._ReaderWhiteList.containsKey(self.owner!.address) != true { return 0.0 } let flowPriceReaderRef = PriceOracleStFlow.account.borrow<&OracleInterface.PriceReader>(from: PriceOracleStFlow._FlowPriceReaderPath) // If no Flow/USD feed's PriceReader resource if flowPriceReaderRef == nil { return 0.0 } let flowToUsd = flowPriceReaderRef!.getMedianPrice() let scaledStFlowToFlow = DelegatorManager.borrowCurrentQuoteEpochSnapshot().scaledQuoteStFlowFlow return LiquidStakingConfig.ScaledUInt256ToUFix64(scaledStFlowToFlow) * flowToUsd } pub fun getRawMedianPrice(): UFix64 { let flowPriceReaderRef = PriceOracleStFlow.account.borrow<&OracleInterface.PriceReader>(from: PriceOracleStFlow._FlowPriceReaderPath) // If no Flow/USD feed's PriceReader resource if flowPriceReaderRef == nil { return 0.0 } let rawFlowToUsd = flowPriceReaderRef!.getRawMedianPrice() let scaledStFlowToFlow = DelegatorManager.borrowCurrentQuoteEpochSnapshot().scaledQuoteStFlowFlow return LiquidStakingConfig.ScaledUInt256ToUFix64(scaledStFlowToFlow) * rawFlowToUsd } pub fun getRawMedianBlockHeight(): UInt64 { let flowPriceReaderRef = PriceOracleStFlow.account.borrow<&OracleInterface.PriceReader>(from: PriceOracleStFlow._FlowPriceReaderPath) // If no Flow/USD feed's PriceReader resource if flowPriceReaderRef == nil { return 0 } return flowPriceReaderRef!.getRawMedianBlockHeight() } pub fun getPriceIdentifier(): String { return self._PriceIdentifier } init() { self._PriceIdentifier = PriceOracleStFlow._PriceIdentifier! } } /// PriceFeeder is *unused* for PriceOracle_stFlowToken, put here simply for implementing the OracleInterface. pub resource PriceFeeder: OracleInterface.PriceFeederPublic { pub fun publishPrice(price: UFix64) { /* Do nothing */ } pub fun setExpiredDuration(blockheightDuration: UInt64) { /* Do nothing */ } pub fun fetchPrice(certificate: &OracleInterface.OracleCertificate): UFix64 { /* Do nothing */ return 0.0 } } /// OracleCertificate is also *unused* as there's no feeder pub resource OracleCertificate: OracleInterface.IdentityCertificate {} /// All external interfaces of this contract pub resource OraclePublic: OracleInterface.OraclePublicInterface_Reader { /// Users who need to read the oracle price should mint this resource and save locally. pub fun mintPriceReader(): @PriceReader { emit MintPriceReader() return <- create PriceReader() } /// Recommended path for PriceReader, users can manage resources by themselves pub fun getPriceReaderStoragePath(): StoragePath { return PriceOracleStFlow._PriceReaderStoragePath! } } /// Get reader whitelist of stFlow/USD price feed pub fun getReaderWhiteList(from: UInt64, to: UInt64): [Address] { let readerAddrs = PriceOracleStFlow._ReaderWhiteList.keys let readerLen = UInt64(readerAddrs.length) assert(from <= to && from < readerLen, message: "Index out of range") var _to = to if _to == 0 || _to == UInt64.max || _to >= readerLen { _to = readerLen-1 } let list: [Address] = [] var cur = from while cur <= _to && cur < readerLen { list.append(readerAddrs[cur]) cur = cur + 1 } return list } pub resource Admin: OracleInterface.Admin { pub fun configOracle( priceIdentifier: String, minFeederNumber: Int, feederStoragePath: StoragePath, feederPublicPath: PublicPath, readerStoragePath: StoragePath ) { emit ConfigOracle( oldType: PriceOracleStFlow._PriceIdentifier, newType: priceIdentifier, oldReaderStoragePath: PriceOracleStFlow._PriceReaderStoragePath, newReaderStoragePath: readerStoragePath ) if (PriceOracleStFlow._PriceIdentifier != priceIdentifier) { PriceOracleStFlow._PriceIdentifier = priceIdentifier } if (PriceOracleStFlow._PriceReaderStoragePath != readerStoragePath) { PriceOracleStFlow._PriceReaderStoragePath = readerStoragePath } } pub fun addReaderWhiteList(readerAddr: Address) { PriceOracleStFlow._ReaderWhiteList[readerAddr] = true emit AddReaderWhiteList(addr: readerAddr) } pub fun delReaderWhiteList(readerAddr: Address) { PriceOracleStFlow._ReaderWhiteList.remove(key: readerAddr) emit DelReaderWhiteList(addr: readerAddr) } // Feeder-related are *unused*. pub fun addFeederWhiteList(feederAddr: Address) {} pub fun delFeederWhiteList(feederAddr: Address) {} pub fun getFeederWhiteListPrice(): [UFix64] { return [] } } init(flowPriceOracle: Address) { self._PriceIdentifier = "stFlow/USD" self._PriceReaderStoragePath = /storage/increment_oracle_reader_stFlowToken self._OraclePublicStoragePath = /storage/oracle_public self._ReaderWhiteList = {} self._reservedFields = {} // Initialize & save flowPriceReader let flowPriceOraclePublicInterfaceReaderRef = getAccount(flowPriceOracle) .getCapability<&{OracleInterface.OraclePublicInterface_Reader}>(OracleConfig.OraclePublicInterface_ReaderPath).borrow() ?? panic("cannot borrow reference to Flow/USD PriceOracle Reader") let flowPriceReaderPath = flowPriceOraclePublicInterfaceReaderRef.getPriceReaderStoragePath() destroy <- self.account.load<@AnyResource>(from: flowPriceReaderPath) let flowPriceReader <- flowPriceOraclePublicInterfaceReaderRef.mintPriceReader() self.account.save(<- flowPriceReader, to: flowPriceReaderPath) self._FlowPriceReaderPath = flowPriceReaderPath // Local admin resource destroy <- self.account.load<@AnyResource>(from: OracleConfig.OracleAdminPath) self.account.save(<-create Admin(), to: OracleConfig.OracleAdminPath) // Public interface destroy <- self.account.load<@AnyResource>(from: self._OraclePublicStoragePath) self.account.save(<-create OraclePublic(), to: self._OraclePublicStoragePath) self.account.link<&{OracleInterface.OraclePublicInterface_Reader}>(OracleConfig.OraclePublicInterface_ReaderPath, target: self._OraclePublicStoragePath) } }

🎉Happy diving into the flow

Contract

🎉Happy diving into the flow