Meta-transaction

Forwarder

ForwardRequest

struct ForwardRequest {
  address from;
  address to;
  uint256 value;
  uint256 gas;
  uint256 nonce;
  uint256 deadline;
  bytes data;
}

_FORWARDREQUEST_TYPEHASH

bytes32 _FORWARDREQUEST_TYPEHASH

DeadlineExpired

error DeadlineExpired()

SignatureDoesNotMatch

error SignatureDoesNotMatch()

constructor

constructor() public

execute

function execute(struct Forwarder.ForwardRequest req, bytes signature) external payable returns (bool, bytes)

Executes a ForwardRequest (meta-tx) if signature is verified, deadline is met and nonce is valid

This implementations allows for out of order execution, by allowing several "timelines" per nonce by splitting the uint256 type space into 128 bit subspaces where each subspace is interpreted as maintaining an ordered timeline. The intent of the design is to allow multiple nonces to be valid at any given time. For a detailed explanation: https://github.com/amxx/permit#out-of-order-execution For an example on how to leverage this functionality, see tests/forwarder/forwarder.test.js Will emit NonceUsed(user, timeline, nonce) for better reporting / UX WARNING: failed transactions do not consume a nonce, unlinke regular ethereum transactions. Please make use of the deadline functionality, and if you want to cancel a request, submit a successful transaction with the same nonce.

Name	Type	Description
req	struct Forwarder.ForwardRequest	ForwardRequest to be executed
signature	bytes	EIP-712 signature of the ForwardRequest

Name	Type	Description
[0]	bool	(success, returnData) of the executed request
[1]	bytes

EIP712WithNonce

NonceUsed

event NonceUsed(address user, uint256 timeline, uint256 nonce)

InvalidNonce

error InvalidNonce(uint256 nonce)

_nonces

mapping(address => mapping(uint256 => uint256)) _nonces

DOMAIN_SEPARATOR

function DOMAIN_SEPARATOR() external view returns (bytes32)

Domain Separator as defined in EIP712

Name	Type	Description
[0]	bytes32	keccak256(typeHash, nameHash, versionHash, block.chainid, address(this))

getNonce

function getNonce(address from) public view virtual returns (uint256)

Gets nonce for the from address in the "default" timeline

For a detailed explanation: https://github.com/amxx/permit#out-of-order-execution

Name	Type	Description
from	address	address

Name	Type	Description
[0]	uint256	nonce

getNonce

function getNonce(address from, uint256 timeline) public view virtual returns (uint256)

Gets nonce for the from address in the specified timeline

For a detailed explanation: https://github.com/amxx/permit#out-of-order-execution

Name	Type	Description
from	address	address
timeline	uint256	where the nonce lives

Name	Type	Description
[0]	uint256	nonce

_verifyAndConsumeNonce

function _verifyAndConsumeNonce(address user, uint256 fullNonce) internal virtual

Extract timeline from nonce, iterates it to consume it, checks for replay protection.

emits NonceUsed(user, timeline, nonce). WARNING: Failed transactions would not consume a nonce, since the reverted transaction won't be able to save in storage.

Name	Type	Description
user	address	address sending the nonce.
fullNonce	uint256	nonce and timeline info in uint256 space