interchain-token-service

Solidity API

InterchainTokenStandard

The is an abstract contract that needs to be extended with an ERC20 implementation. See InterchainToken for an example implementation.

interchainTokenId

function interchainTokenId() public view virtual returns (bytes32 tokenId_)

Getter for the tokenId used for this token.

Needs to be overwritten.

Return Values

Name	Type	Description
tokenId_	bytes32	The tokenId that this token is registerred under.

interchainTokenService

function interchainTokenService() public view virtual returns (address service)

Getter for the interchain token service.

Needs to be overwritten.

Return Values

Name	Type	Description
service	address	The address of the interchain token service.

interchainTransfer

function interchainTransfer(string destinationChain, bytes recipient, uint256 amount, bytes metadata) external payable

Implementation of the interchainTransfer method

We chose to either pass metadata as raw data on a remote contract call, or if no data is passed, just do a transfer. A different implementation could use metadata to specify a function to invoke, or for other purposes as well.

Parameters

Name	Type	Description
destinationChain	string	The destination chain identifier.
recipient	bytes	The bytes representation of the address of the recipient.
amount	uint256	The amount of token to be transferred.
metadata	bytes	Either empty, just to facilitate an interchain transfer, or the data to be passed for an interchain contract call with transfer as per semantics defined by the token service.

interchainTransferFrom

function interchainTransferFrom(address sender, string destinationChain, bytes recipient, uint256 amount, bytes metadata) external payable

Implementation of the interchainTransferFrom method

We chose to either pass metadata as raw data on a remote contract call, or, if no data is passed, just do a transfer. A different implementation could use metadata to specify a function to invoke, or for other purposes as well.

Parameters

Name	Type	Description
sender	address	The sender of the tokens. They need to have approved msg.sender before this is called.
destinationChain	string	The string representation of the destination chain.
recipient	bytes	The bytes representation of the address of the recipient.
amount	uint256	The amount of token to be transferred.
metadata	bytes	Either empty, just to facilitate an interchain transfer, or the data to be passed to an interchain contract call and transfer.

_beforeInterchainTransfer

function _beforeInterchainTransfer(address from, string destinationChain, bytes destinationAddress, uint256 amount, bytes metadata) internal virtual

A method to be overwritten that will be called before an interchain transfer. One can approve the tokenManager here if needed, to allow users for a 1-call transfer in case of a lock-unlock token manager.

Parameters

Name	Type	Description
from	address	The sender of the tokens. They need to have approved msg.sender before this is called.
destinationChain	string	The string representation of the destination chain.
destinationAddress	bytes	The bytes representation of the address of the recipient.
amount	uint256	The amount of token to be transferred.
metadata	bytes	Either empty, just to facilitate an interchain transfer, or the data to be passed to an interchain contract call and transfer.

_spendAllowance

function _spendAllowance(address sender, address spender, uint256 amount) internal virtual

A method to be overwritten that will decrease the allowance of the spender from sender by amount.

Needs to be overwritten. This provides flexibility for the choice of ERC20 implementation used. Must revert if allowance is not sufficient.