VendingMachineV2

VendingMachineV2

VendingMachineV2 is used to exchange tBTC v1 to tBTC v2 in a 1:1 ratio during the process of tBTC v1 bridge sunsetting. The redeemer selected by the DAO based on the "TIP-027b tBTC v1: The Sunsetting" proposal will deposit tBTC v2 tokens into VendingMachineV2 so that outstanding tBTC v1 token owners can upgrade to tBTC v2 tokens. The redeemer will withdraw the tBTC v1 tokens deposited into the contract to perform tBTC v1 redemptions. The redeemer may decide to withdraw their deposited tBTC v2 at any moment in time. The amount withdrawable is lower than the amount deposited in case tBTC v1 was exchanged for tBTC v2. This contract is owned by the redeemer.

tbtcV1

contract IERC20 tbtcV1

tbtcV2

contract TBTC tbtcV2

Exchanged

event Exchanged(address to, uint256 amount)

Deposited

event Deposited(address from, uint256 amount)

Withdrawn

event Withdrawn(address token, address to, uint256 amount)

constructor

constructor(contract IERC20 _tbtcV1, contract TBTC _tbtcV2) public

exchange

function exchange(uint256 amount) external

Exchange tBTC v1 for tBTC v2 in a 1:1 ratio. The caller needs to have at least amount of tBTC v1 balance approved for transfer to the VendingMachineV2 before calling this function.

Parameters

Name	Type	Description
amount	uint256	The amount of tBTC v1 to exchange for tBTC v2.

receiveApproval

function receiveApproval(address from, uint256 amount, address token, bytes) external

Exchange tBTC v1 for tBTC v2 in a 1:1 ratio. The caller needs to have at least amount of tBTC v1 balance approved for transfer to the VendingMachineV2 before calling this function.

This function is a shortcut for approve + exchange. Only tBTC v1 token caller is allowed and only tBTC v1 is allowed as a token to transfer.

Parameters

Name	Type	Description
from	address	tBTC v1 token holder exchanging tBTC v1 to tBTC v2.
amount	uint256	The amount of tBTC v1 to exchange for tBTC v2.
token	address	tBTC v1 token address.
	bytes

depositTbtcV2

function depositTbtcV2(uint256 amount) external

Allows to deposit tBTC v2 tokens to the contract. VendingMachineV2 can not mint tBTC v2 tokens so tBTC v2 needs to be deposited into the contract so that tBTC v1 to tBTC v2 exchange can happen. The caller needs to have at least amount of tBTC v2 balance approved for transfer to the VendingMachineV2 before calling this function.

This function is for the redeemer and tBTC v1 operators. This is NOT a function for tBTC v1 token holders.

Parameters

Name	Type	Description
amount	uint256	The amount of tBTC v2 to deposit into the contract.

withdrawFunds

function withdrawFunds(contract IERC20 token, address recipient, uint256 amount) external

Allows the contract owner to withdraw tokens. This function is used in two cases: 1) when the redeemer wants to redeem tBTC v1 tokens to perform tBTC v2 redemptions; 2) when the deadline for tBTC v1 -> tBTC v2 exchange passed and the redeemer wants their tBTC v2 back.

This function is for the redeemer. This is NOT a function for tBTC v1 token holders.

Parameters

Name	Type	Description
token	contract IERC20	The address of a token to withdraw.
recipient	address	The address which should receive withdrawn tokens.
amount	uint256	The amount to withdraw.

_exchange

function _exchange(address tokenOwner, uint256 amount) internal