TezFin/contracts/CFA12.py at main · StableTechnologies/TezFin · GitHub

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import smartpy as sp

CTErrors = sp.io.import_script_from_url(
    "file:contracts/errors/CTokenErrors.py")
EC = CTErrors.ErrorCodes

CToken = sp.io.import_script_from_url("file:contracts/CToken.py")


class CFA12(CToken.CToken):
    def __init__(self, comptroller_, interestRateModel_, initialExchangeRateMantissa_, administrator_, metadata_, token_metadata_, fa1_2_TokenAddress_, **extra_storage):
        CToken.CToken.__init__(self,
                               comptroller_,
                               interestRateModel_,
                               initialExchangeRateMantissa_,
                               administrator_,
                               metadata_,
                               token_metadata_,
                               fa1_2_TokenAddress=fa1_2_TokenAddress_,
                               currentCash=sp.nat(0),
                               **extra_storage)

    def getCashImpl(self):
        return self.data.currentCash

    def updateCash(self):
        cashSum = sp.compute(self.data.currentCash +
                             self.data.totalSupply + self.data.totalReserves)
        # prevent transaction failing if CToken is not listed in underlying fa12 yet
        with sp.if_(cashSum > 0):
            self.activateOp(CToken.OP.CTokenOperations.GET_CASH)
            handle = sp.contract(sp.TPair(sp.TAddress, sp.TContract(
                sp.TNat)), self.data.fa1_2_TokenAddress, "getBalance").open_some()
            sp.transfer(sp.pair(sp.self_address, sp.self_entry_point(
                "setCash")), sp.mutez(0), handle)

    @sp.entry_point(lazify=True)
    def setCash(self, value):
        sp.set_type(value, sp.TNat)
        self.verifyAndFinishActiveOp(CToken.OP.CTokenOperations.GET_CASH)
        sp.verify(sp.sender == self.data.fa1_2_TokenAddress,
                  EC.CT_INVALID_CASH_SENDER)
        self.data.currentCash = value

    def doTransferIn(self, from_, amount):
        # Listed FA1.2 underlyings must credit exactly ``amount`` on every
        # successful transfer. Fee-on-transfer and transfer-time-rebasing
        # tokens are unsupported because currentCash is updated by amount.
        self.transferFA12(from_, sp.self_address, amount,
                          self.data.fa1_2_TokenAddress)
        # Keep the accounting cache in lockstep with the scheduled token
        # transfer. Subsequent operations in the same operation group use this
        # value to price shares and check liquidity.
        self.data.currentCash += amount

    def doTransferOut(self, to_, amount, isContract=False):
        self.data.currentCash = self.sub_nat_nat(self.data.currentCash, amount)
        self.transferFA12(sp.self_address, to_, amount,
                          self.data.fa1_2_TokenAddress)

    def verifySweepFA12(self, tokenAddress):
        sp.verify(tokenAddress != self.data.fa1_2_TokenAddress,
                  EC.CT_SWEEP_UNDERLYING)