1  // SPDX-License-Identifier: GPL-2.0-or-later
 2  pragma solidity >=0.6.0;
 3  
 4  /// @title Interface for permit
 5  /// @notice Interface used by DAI/CHAI for permit
 6  interface IERC20PermitAllowed {
 7      /// @notice Approve the spender to spend some tokens via the holder signature
 8      /// @dev This is the permit interface used by DAI and CHAI
 9      /// @param holder The address of the token holder, the token owner
10      /// @param spender The address of the token spender
11      /// @param nonce The holder's nonce, increases at each call to permit
12      /// @param expiry The timestamp at which the permit is no longer valid
13      /// @param allowed Boolean that sets approval amount, true for type(uint256).max and false for 0
14      /// @param v Must produce valid secp256k1 signature from the holder along with `r` and `s`
15      /// @param r Must produce valid secp256k1 signature from the holder along with `v` and `s`
16      /// @param s Must produce valid secp256k1 signature from the holder along with `r` and `v`
17      function permit(
18          address holder,
19          address spender,
20          uint256 nonce,
21          uint256 expiry,
22          bool allowed,
23          uint8 v,
24          bytes32 r,
25          bytes32 s
26      ) external;
27  }