95 lines
3.0 KiB
Rust
95 lines
3.0 KiB
Rust
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use ethers::{
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abi,
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abi::Token,
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prelude::U256,
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types::Address,
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utils,
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utils::{keccak256, parse_ether},
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};
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const UNISWAP_V2_USDC_ETH_PAIR: &'static str = "0xB4e16d0168e52d35CaCD2c6185b44281Ec28C9Dc";
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// Generate the EIP712 permit hash to sign for a Uniswap V2 pair.
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// https://eips.ethereum.org/EIPS/eip-712
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// https://eips.ethereum.org/EIPS/eip-2612
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fn main() {
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// Test data
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let owner: Address = "0x617072Cb2a1897192A9d301AC53fC541d35c4d9D"
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.parse()
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.unwrap();
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let spender: Address = "0x2819c144D5946404C0516B6f817a960dB37D4929"
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.parse()
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.unwrap();
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let value = parse_ether(10).unwrap();
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let nonce = U256::from(1);
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let deadline = U256::from(3133728498 as u32);
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let verifying_contract: Address = UNISWAP_V2_USDC_ETH_PAIR.parse().unwrap();
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let name = "Uniswap V2";
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let version = "1";
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let chainid = 1;
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// Typehash for the permit() function
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let permit_typehash = utils::keccak256(
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"Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)",
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);
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// Typehash for the struct used to generate the domain separator
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let domain_typehash = keccak256(
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"EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)",
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);
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// Corresponds to solidity's abi.encode()
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let domain_separator_input = abi::encode(&vec![
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Token::Uint(U256::from(domain_typehash)),
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Token::Uint(U256::from(keccak256(&name))),
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Token::Uint(U256::from(keccak256(&version))),
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Token::Uint(U256::from(chainid)),
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Token::Address(verifying_contract),
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]);
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// Corresponds to the following solidity:
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// DOMAIN_SEPARATOR = keccak256(
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// abi.encode(
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// keccak256('EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)'),
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// keccak256(bytes(name)),
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// keccak256(bytes('1')),
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// chainId,
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// address(this)
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// )
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// );
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let domain_separator = keccak256(&domain_separator_input);
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// Corresponds to solidity's abi.encode()
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let struct_input = abi::encode(&vec![
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Token::Uint(U256::from(permit_typehash)),
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Token::Address(owner),
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Token::Address(spender),
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Token::Uint(value),
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Token::Uint(nonce),
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Token::Uint(deadline),
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]);
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let struct_hash = keccak256(&struct_input);
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// Corresponds to solidity's abi.encodePacked()
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let digest_input = [
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&[0x19, 0x01],
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domain_separator.as_ref(),
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struct_hash.as_ref(),
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]
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.concat();
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// Matches the following solidity:
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// bytes32 digest = keccak256(
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// abi.encodePacked(
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// '\x19\x01',
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// DOMAIN_SEPARATOR,
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// keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, nonces[owner]++, deadline))
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// )
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// );
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let permit_hash = keccak256(&digest_input);
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assert_eq!(
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hex::encode(permit_hash),
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"7b90248477de48c0b971e0af8951a55974733455191480e1e117c86cc2a6cd03"
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);
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}
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