VendingMachine
VendingMachine
The Vending Machine is the owner of TBTC v2 token and can mint TBTC v2 tokens in 1:1 ratio from TBTC v1 tokens with TBTC v1 deposited in the contract as collateral. TBTC v2 can be unminted back to TBTC v1 with or without a fee - fee parameter is controlled by the Governance. This implementation acts as a bridge between TBTC v1 and TBTC v2 token, allowing to mint TBTC v2 before the system is ready and fully operational without sacrificing any security guarantees and decentralization of the project. Vending Machine can be upgraded in a two-step, governance-controlled process. The new version of the Vending Machine will receive the ownership of TBTC v2 token and entire TBTC v1 balance stored as collateral. It is expected that this process will be executed before the v2 system launch. There is an optional unmint fee with a value that can be updated in a two-step, governance-controlled process. All governable parameters are controlled by two roles: update initiator and finalizer. There is a separate initiator role for unmint fee update and vending machine upgrade. The initiator proposes the change by initiating the update and the finalizer (contract owner) may approve it by finalizing the change after the governance delay passes.
GOVERNANCE_DELAY
uint256 GOVERNANCE_DELAY
The time delay that needs to pass between initializing and finalizing update of any governable parameter in this contract.
FLOATING_POINT_DIVISOR
uint256 FLOATING_POINT_DIVISOR
Divisor for precision purposes. Used to represent fractions in parameter values.
tbtcV1
contract IERC20 tbtcV1
tbtcV2
contract TBTC tbtcV2
unmintFee
uint256 unmintFee
The fee for unminting TBTC v2 back into TBTC v1 represented as 1e18 precision fraction. The fee is proportional to the amount being unminted and added on the top of the amount being unminted. To calculate the fee value, the amount being unminted needs to be multiplied by unmintFee
and divided by 1e18. For example, unmintFee
set to 1000000000000000 means that 0.001 of the amount being unminted needs to be paid to the VendingMachine
as an unminting fee on the top of the amount being unminted.
newUnmintFee
uint256 newUnmintFee
unmintFeeUpdateInitiatedTimestamp
uint256 unmintFeeUpdateInitiatedTimestamp
unmintFeeUpdateInitiator
address unmintFeeUpdateInitiator
newVendingMachine
address newVendingMachine
The address of a new vending machine. Set only when the upgrade process is pending. Once the upgrade gets finalized, the new vending machine will become an owner of TBTC v2 token.
vendingMachineUpgradeInitiatedTimestamp
uint256 vendingMachineUpgradeInitiatedTimestamp
vendingMachineUpgradeInitiator
address vendingMachineUpgradeInitiator
UnmintFeeUpdateInitiated
event UnmintFeeUpdateInitiated(uint256 newUnmintFee, uint256 timestamp)
UnmintFeeUpdated
event UnmintFeeUpdated(uint256 newUnmintFee)
VendingMachineUpgradeInitiated
event VendingMachineUpgradeInitiated(address newVendingMachine, uint256 timestamp)
VendingMachineUpgraded
event VendingMachineUpgraded(address newVendingMachine)
Minted
event Minted(address recipient, uint256 amount)
Unminted
event Unminted(address recipient, uint256 amount, uint256 fee)
only
modifier only(address authorizedCaller)
onlyAfterGovernanceDelay
modifier onlyAfterGovernanceDelay(uint256 changeInitiatedTimestamp)
constructor
constructor(contract IERC20 _tbtcV1, contract TBTC _tbtcV2, uint256 _unmintFee) public
mint
function mint(uint256 amount) external
Mints TBTC v2 to the caller from TBTC v1 with 1:1 ratio. The caller needs to have at least amount
of TBTC v1 balance approved for transfer to the VendingMachine
before calling this function.
Parameters
amount
uint256
The amount of TBTC v2 to mint from TBTC v1
receiveApproval
function receiveApproval(address from, uint256 amount, address token, bytes) external
Mints TBTC v2 to from
address from TBTC v1 with 1:1 ratio. from
address needs to have at least amount
of TBTC v1 balance approved for transfer to the VendingMachine
before calling this function.
This function is a shortcut for approve + mint. Only TBTC v1 caller is allowed and only TBTC v1 is allowed as a token to transfer.
Parameters
from
address
TBTC v1 token holder minting TBTC v2 tokens
amount
uint256
The amount of TBTC v2 to mint from TBTC v1
token
address
TBTC v1 token address
bytes
unmint
function unmint(uint256 amount) external
Unmints TBTC v2 from the caller into TBTC v1. Depending on unmintFee
value, may require paying an additional unmint fee in TBTC v2 in addition to the amount being unminted. To see what is the value of the fee, please call unmintFeeFor(amount)
function. The caller needs to have at least amount + unmintFeeFor(amount)
of TBTC v2 balance approved for transfer to the VendingMachine
before calling this function.
Parameters
amount
uint256
The amount of TBTC v2 to unmint to TBTC v1
withdrawFees
function withdrawFees(address recipient, uint256 amount) external
Allows the Governance to withdraw unmint fees accumulated by VendingMachine
.
Parameters
recipient
address
The address receiving the fees
amount
uint256
The amount of fees in TBTC v2 to withdraw
initiateUnmintFeeUpdate
function initiateUnmintFeeUpdate(uint256 _newUnmintFee) external
Initiates unmint fee update process. The update process needs to be finalized with a call to finalizeUnmintFeeUpdate
function after the GOVERNANCE_DELAY
passes. Only unmint fee update initiator role can initiate the update.
Parameters
_newUnmintFee
uint256
The new unmint fee
finalizeUnmintFeeUpdate
function finalizeUnmintFeeUpdate() external
Allows the contract owner to finalize unmint fee update process. The update process needs to be first initiated with a call to initiateUnmintFeeUpdate
and the GOVERNANCE_DELAY
needs to pass.
initiateVendingMachineUpgrade
function initiateVendingMachineUpgrade(address _newVendingMachine) external
Initiates vending machine upgrade process. The upgrade process needs to be finalized with a call to finalizeVendingMachineUpgrade
function after the GOVERNANCE_DELAY
passes. Only vending machine upgrade initiator role can initiate the upgrade.
Parameters
_newVendingMachine
address
The new vending machine address
finalizeVendingMachineUpgrade
function finalizeVendingMachineUpgrade() external
Allows the contract owner to finalize vending machine upgrade process. The upgrade process needs to be first initiated with a call to initiateVendingMachineUpgrade
and the GOVERNANCE_DELAY
needs to pass. Once the upgrade is finalized, the new vending machine will become an owner of TBTC v2 token and all TBTC v1 held by this contract will be transferred to the new vending machine.
transferUnmintFeeUpdateInitiatorRole
function transferUnmintFeeUpdateInitiatorRole(address newInitiator) external
Transfers unmint fee update initiator role to another address. Can be called only by the current unmint fee update initiator.
Parameters
newInitiator
address
The new unmint fee update initiator
transferVendingMachineUpgradeInitiatorRole
function transferVendingMachineUpgradeInitiatorRole(address newInitiator) external
Transfers vending machine upgrade initiator role to another address. Can be called only by the current vending machine upgrade initiator.
Parameters
newInitiator
address
The new vending machine upgrade initiator
getRemainingUnmintFeeUpdateTime
function getRemainingUnmintFeeUpdateTime() external view returns (uint256)
Get the remaining time that needs to pass until unmint fee update can be finalized by the Governance. If the update has not been initiated, the function reverts.
getRemainingVendingMachineUpgradeTime
function getRemainingVendingMachineUpgradeTime() external view returns (uint256)
Get the remaining time that needs to pass until vending machine upgrade can be finalized by the Governance. If the upgrade has not been initiated, the function reverts.
unmintFeeFor
function unmintFeeFor(uint256 amount) public view returns (uint256)
Calculates the fee that needs to be paid to the VendingMachine
to unmint the given amount of TBTC v2 back into TBTC v1.
_mint
function _mint(address tokenOwner, uint256 amount) internal
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