IAllowanceTransfer
Inherits: IEIP712
Handles ERC20 token permissions through signature based allowance setting and ERC20 token transfers by checking allowed amounts
Requires user's token approval on the Permit2 contract
Functions
allowance
A mapping from owner address to token address to spender address to PackedAllowance struct, which contains details and conditions of the approval.
The mapping is indexed in the above order see: allowance[ownerAddress][tokenAddress][spenderAddress]
The packed slot holds the allowed amount, expiration at which the allowed amount is no longer valid, and current nonce thats updated on any signature based approvals.
function allowance(address user, address token, address spender)
external
view
returns (uint160 amount, uint48 expiration, uint48 nonce);
approve
Approves the spender to use up to amount of the specified token up until the expiration
The packed allowance also holds a nonce, which will stay unchanged in approve
Setting amount to type(uint160).max sets an unlimited approval
function approve(address token, address spender, uint160 amount, uint48 expiration) external;
Parameters
| Name | Type | Description |
|---|---|---|
token | address | The token to approve |
spender | address | The spender address to approve |
amount | uint160 | The approved amount of the token |
expiration | uint48 | The timestamp at which the approval is no longer valid |
permit
Permit a spender to a given amount of the owners token via the owner's EIP-712 signature
May fail if the owner's nonce was invalidated in-flight by invalidateNonce
function permit(address owner, PermitSingle memory permitSingle, bytes calldata signature) external;
Parameters
| Name | Type | Description |
|---|---|---|
owner | address | The owner of the tokens being approved |
permitSingle | PermitSingle | Data signed over by the owner specifying the terms of approval |
signature | bytes | The owner's signature over the permit data |
permit
Permit a spender to the signed amounts of the owners tokens via the owner's EIP-712 signature
May fail if the owner's nonce was invalidated in-flight by invalidateNonce
function permit(address owner, PermitBatch memory permitBatch, bytes calldata signature) external;
Parameters
| Name | Type | Description |
|---|---|---|
owner | address | The owner of the tokens being approved |
permitBatch | PermitBatch | Data signed over by the owner specifying the terms of approval |
signature | bytes | The owner's signature over the permit data |
transferFrom
Transfer approved tokens from one address to another
Requires the from address to have approved at least the desired amount of tokens to msg.sender.
function transferFrom(address from, address to, uint160 amount, address token) external;
Parameters
| Name | Type | Description |
|---|---|---|
from | address | The address to transfer from |
to | address | The address of the recipient |
amount | uint160 | The amount of the token to transfer |
token | address | The token address to transfer |
transferFrom
Transfer approved tokens in a batch
Requires the from addresses to have approved at least the desired amount of tokens to msg.sender.
function transferFrom(AllowanceTransferDetails[] calldata transferDetails) external;
Parameters
| Name | Type | Description |
|---|---|---|
transferDetails | AllowanceTransferDetails[] | Array of owners, recipients, amounts, and tokens for the transfers |
lockdown
Enables performing a "lockdown" of the sender's Permit2 identity by batch revoking approvals
function lockdown(TokenSpenderPair[] calldata approvals) external;
Parameters
| Name | Type | Description |
|---|---|---|
approvals | TokenSpenderPair[] | Array of approvals to revoke. |
invalidateNonces
Invalidate nonces for a given (token, spender) pair
Can't invalidate more than 2**16 nonces per transaction.
function invalidateNonces(address token, address spender, uint48 newNonce) external;
Parameters
| Name | Type | Description |
|---|---|---|
token | address | The token to invalidate nonces for |
spender | address | The spender to invalidate nonces for |
newNonce | uint48 | The new nonce to set. Invalidates all nonces less than it. |
Events
NonceInvalidation
Emits an event when the owner successfully invalidates an ordered nonce.
event NonceInvalidation(
address indexed owner, address indexed token, address indexed spender, uint48 newNonce, uint48 oldNonce
);
Approval
Emits an event when the owner successfully sets permissions on a token for the spender.
event Approval(
address indexed owner, address indexed token, address indexed spender, uint160 amount, uint48 expiration
);
Permit
Emits an event when the owner successfully sets permissions using a permit signature on a token for the spender.
event Permit(
address indexed owner,
address indexed token,
address indexed spender,
uint160 amount,
uint48 expiration,
uint48 nonce
);
Lockdown
Emits an event when the owner sets the allowance back to 0 with the lockdown function.
event Lockdown(address indexed owner, address token, address spender);
Errors
AllowanceExpired
Thrown when an allowance on a token has expired.
error AllowanceExpired(uint256 deadline);
Parameters
| Name | Type | Description |
|---|---|---|
deadline | uint256 | The timestamp at which the allowed amount is no longer valid |
InsufficientAllowance
Thrown when an allowance on a token has been depleted.
error InsufficientAllowance(uint256 amount);
Parameters
| Name | Type | Description |
|---|---|---|
amount | uint256 | The maximum amount allowed |
ExcessiveInvalidation
Thrown when too many nonces are invalidated.
error ExcessiveInvalidation();
Structs
PermitDetails
The permit data for a token
struct PermitDetails {
address token;
uint160 amount;
uint48 expiration;
uint48 nonce;
}
PermitSingle
The permit message signed for a single token allowance
struct PermitSingle {
PermitDetails details;
address spender;
uint256 sigDeadline;
}
PermitBatch
The permit message signed for multiple token allowances
struct PermitBatch {
PermitDetails[] details;
address spender;
uint256 sigDeadline;
}
PackedAllowance
The saved permissions
This info is saved per owner, per token, per spender and all signed over in the permit message
Setting amount to type(uint160).max sets an unlimited approval
struct PackedAllowance {
uint160 amount;
uint48 expiration;
uint48 nonce;
}
TokenSpenderPair
A token spender pair.
struct TokenSpenderPair {
address token;
address spender;
}
AllowanceTransferDetails
Details for a token transfer.
struct AllowanceTransferDetails {
address from;
address to;
uint160 amount;
address token;
}