wards. If your address isn’t a ward, you can’t test minting operations.
Setting up as a ward through state overrides
To simulate a transaction where we mint DAI, we need to override the state to make our address appear as a ward. We need to adjust thewards map in the DAI contract to include our address with the necessary permissions.
To be able to mint, the sender of the transaction must be a ward. In other words, the following condition must hold: wards['0xe2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2'] == 1.
In the API request, assign a map of overrides to the state_objects object. This map points to specific storage locations in the smart contract and assigns new values for the simulation.
- DAI contract address:
0x6b175474e89094c44da98b954eedeac495271d0f - Storage slot location:
0xedd7d04419e9c48ceb6055956cbb4e2091ae310313a4d1fa7cbcfe7561616e03 - Override value:
0x0000000000000000000000000000000000000000000000000000000000000001
example.json
{
"state_objects": {
"0x6b175474e89094c44da98b954eedeac495271d0f": {
"storage": {
"0xedd7d04419e9c48ceb6055956cbb4e2091ae310313a4d1fa7cbcfe7561616e03": "0x0000000000000000000000000000000000000000000000000000000000000001"
}
}
}
}
TENDERLY_ACCOUNT_SLUG and TENDERLY_ACCESS_KEY set as environment variables. Learn how to obtain the slug and access key.
- Request
- Response
example.ts
dotenv.config();
// assuming environment variables TENDERLY_ACCOUNT_SLUG, TENDERLY_PROJECT_SLUG and TENDERLY_ACCESS_KEY are set
// https://docs.tenderly.co/platform/account/projects/slug
// https://docs.tenderly.co/platform/account/projects/api-tokens
const { TENDERLY_ACCOUNT_SLUG, TENDERLY_PROJECT_SLUG, TENDERLY_ACCESS_KEY } = process.env;
const mintDai = async () => {
console.time('Simulation');
const fakeWardAddress = '0xe2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2';
// calculate the storage location of `wards[fakeWardAddress]`
// yields 0xedd7d04419e9c48ceb6055956cbb4e2091ae310313a4d1fa7cbcfe7561616e03
const overrideStorageLocation = ethers.utils.keccak256(
ethers.utils.concat([
ethers.utils.hexZeroPad(fakeWardAddress, 32), // the ward address (address 0x000..0) - mapping key
ethers.utils.hexZeroPad('0x0', 32), // the wards slot is 0th in the DAI contract - the mapping variable
]),
);
console.log('Storage Override Location', overrideStorageLocation);
const mint = (
await axios.post(
`https://api.tenderly.co/api/v1/account/${TENDERLY_ACCOUNT_SLUG}/project/${TENDERLY_PROJECT_SLUG}/simulate`,
// the transaction
{
save: true,
save_if_fails: true,
simulation_type: 'full',
network_id: '1',
from: '0xe2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2',
to: '0x6b175474e89094c44da98b954eedeac495271d0f',
input:
'0x40c10f19000000000000000000000000e58b9ee93700a616b50509c8292977fa7a0f8ce10000000000000000000000000000000000000000000000001bc16d674ec80000',
gas: 8000000,
state_objects: {
'0x6b175474e89094c44da98b954eedeac495271d0f': {
storage: {
'0xedd7d04419e9c48ceb6055956cbb4e2091ae310313a4d1fa7cbcfe7561616e03':
'0x0000000000000000000000000000000000000000000000000000000000000001',
},
},
},
},
{
headers: {
'X-Access-Key': TENDERLY_ACCESS_KEY as string,
},
},
)
).data;
console.timeEnd('Simulation');
console.log(JSON.stringify(mint, null, 2));
// TODO: extract token transferred
};
mintDai();
Storage Override Location 0xedd7d04419e9c48ceb6055956cbb4e2091ae310313a4d1fa7cbcfe7561616e03
Simulation: 185.029ms
{
"transaction": {
"hash": "0xd9d52b2cb6b6d8d8640bc2dee86050a623401fe39d7fbc4ab46ffd7ff3ea6ab6",
"block_hash": "",
"block_number": 16598541,
"from": "0xe2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2",
"gas": 8000000,
"gas_price": 0,
"gas_fee_cap": 0,
"gas_tip_cap": 0,
"cumulative_gas_used": 0,
"gas_used": 53465,
"effective_gas_price": 0,
"input": "0x40c10f19000000000000000000000000e58b9ee93700a616b50509c8292977fa7a0f8ce10000000000000000000000000000000000000000000000001bc16d674ec80000",
"nonce": 0,
"to": "0x6b175474e89094c44da98b954eedeac495271d0f",
"index": 0,
"value": "0x",
"access_list": null,
"status": true,
"addresses": [
"0xe2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2",
"0x6b175474e89094c44da98b954eedeac495271d0f"
],
"contract_ids": [
"eth:1:0xe2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2",
"eth:1:0x6b175474e89094c44da98b954eedeac495271d0f"
],
"network_id": "1",
"timestamp": "2023-02-10T13:04:56Z",
"function_selector": "",
"l1_block_number": 0,
"l1_timestamp": 0,
"deposit_tx": false,
"system_tx": false,
"mint": null,
"sig": {
"v": "0x0",
"r": "0x0",
"s": "0x0"
},
"transaction_info": {
"contract_id": "eth:1:0x6b175474e89094c44da98b954eedeac495271d0f",
"block_number": 16598541,
"transaction_id": "0xd9d52b2cb6b6d8d8640bc2dee86050a623401fe39d7fbc4ab46ffd7ff3ea6ab6",
"contract_address": "0x6b175474e89094c44da98b954eedeac495271d0f",
"method": "mint",
"parameters": null,
"intrinsic_gas": 21620,
"refund_gas": 0,
"call_trace": {
"hash": "0xd9d52b2cb6b6d8d8640bc2dee86050a623401fe39d7fbc4ab46ffd7ff3ea6ab6",
"contract_name": "Dai",
"function_name": "mint",
"function_pc": 3948,
"function_op": "JUMPDEST",
"function_file_index": 0,
"function_code_start": 5501,
"function_line_number": 134,
"function_code_length": 202,
"absolute_position": 88,
"caller_pc": 0,
"caller_op": "CALL",
"call_type": "CALL",
"from": "0xe2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2",
"from_balance": "0",
"to": "0x6b175474e89094c44da98b954eedeac495271d0f",
"to_balance": "0",
"value": "0",
"caller": {
"address": "0xe2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2",
"balance": "0"
},
"block_timestamp": "0001-01-01T00:00:00Z",
"gas": 7978380,
"gas_used": 31845,
"intrinsic_gas": 21620,
"input": "0x40c10f19000000000000000000000000e58b9ee93700a616b50509c8292977fa7a0f8ce10000000000000000000000000000000000000000000000001bc16d674ec80000",
"decoded_input": [
{
"soltype": {
"name": "usr",
"type": "address",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
"type": "address"
}
},
"value": "0xe58b9ee93700a616b50509c8292977fa7a0f8ce1"
},
{
"soltype": {
"name": "wad",
"type": "uint256",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
"type": "uint"
}
},
"value": "2000000000000000000"
}
],
"nonce_diff": [
{
"address": "0xe2E2E2e2e2e2E2E2E2E2e2E2e2E2E2e2e2e2E2e2",
"original": "0",
"dirty": "1"
}
],
"state_diff": [
{
"address": "0x6b175474e89094c44da98b954eedeac495271d0f",
"soltype": {
"name": "totalSupply",
"type": "uint256",
"storage_location": "storage",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000001",
"indexed": false,
"simple_type": {
"type": "uint"
}
},
"original": "5090814826520179690761462859",
"dirty": "5090814828520179690761462859",
"raw": [
{
"address": "0x6b175474e89094c44da98b954eedeac495271d0f",
"key": "0x0000000000000000000000000000000000000000000000000000000000000001",
"original": "0x0000000000000000000000000000000000000000107305f8bb52a43b529da44b",
"dirty": "0x0000000000000000000000000000000000000000107305f8d71411a2a165a44b"
}
]
},
{
"address": "0x6b175474e89094c44da98b954eedeac495271d0f",
"soltype": {
"name": "balanceOf",
"type": "mapping (address => uint256)",
"storage_location": "storage",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000002",
"indexed": false
},
"original": {
"0xe58b9ee93700a616b50509c8292977fa7a0f8ce1": "0"
},
"dirty": {
"0xe58b9ee93700a616b50509c8292977fa7a0f8ce1": "2000000000000000000"
},
"raw": [
{
"address": "0x6b175474e89094c44da98b954eedeac495271d0f",
"key": "0x9b5472766fd311751f6a33c8e30061e20a26259ca626cf5a2feaadf96903cd9e",
"original": "0x0000000000000000000000000000000000000000000000000000000000000000",
"dirty": "0x0000000000000000000000000000000000000000000000001bc16d674ec80000"
}
]
}
],
"logs": [
{
"name": "Transfer",
"anonymous": false,
"inputs": [
{
"soltype": {
"name": "src",
"type": "address",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": true,
"simple_type": {
"type": "address"
}
},
"value": "0x0000000000000000000000000000000000000000"
},
{
"soltype": {
"name": "dst",
"type": "address",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": true,
"simple_type": {
"type": "address"
}
},
"value": "0xe58b9ee93700a616b50509c8292977fa7a0f8ce1"
},
{
"soltype": {
"name": "wad",
"type": "uint256",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
"type": "uint"
}
},
"value": "2000000000000000000"
}
],
"raw": {
"address": "0x6b175474e89094c44da98b954eedeac495271d0f",
"topics": [
"0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef",
"0x0000000000000000000000000000000000000000000000000000000000000000",
"0x000000000000000000000000e58b9ee93700a616b50509c8292977fa7a0f8ce1"
],
"data": "0x0000000000000000000000000000000000000000000000001bc16d674ec80000"
}
}
],
"output": "0x",
"decoded_output": null,
"network_id": "1",
"calls": [
{
"hash": "",
"contract_name": "Dai",
"function_name": "add",
"function_pc": 7825,
"function_op": "JUMPDEST",
"function_file_index": 0,
"function_code_start": 3853,
"function_line_number": 94,
"function_code_length": 102,
"absolute_position": 136,
"caller_pc": 4200,
"caller_op": "JUMP",
"caller_file_index": 0,
"caller_line_number": 135,
"caller_code_start": 5579,
"caller_code_length": 24,
"call_type": "JUMPDEST",
"from": "0x6b175474e89094c44da98b954eedeac495271d0f",
"from_balance": null,
"to": "0x6b175474e89094c44da98b954eedeac495271d0f",
"to_balance": null,
"value": null,
"caller": {
"address": "0xe2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2",
"balance": "0"
},
"block_timestamp": "0001-01-01T00:00:00Z",
"gas": 7973640,
"gas_used": 62,
"input": "0x",
"decoded_input": [
{
"soltype": {
"name": "x",
"type": "uint256",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
"type": "uint"
}
},
"value": "0"
},
{
"soltype": {
"name": "y",
"type": "uint256",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
"type": "uint"
}
},
"value": "2000000000000000000"
}
],
"output": "0x",
"decoded_output": [
{
"soltype": {
"name": "z",
"type": "uint256",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
"type": "uint"
}
},
"value": "2000000000000000000"
}
],
"network_id": "",
"calls": null
},
{
"hash": "",
"contract_name": "Dai",
"function_name": "add",
"function_pc": 7825,
"function_op": "JUMPDEST",
"function_file_index": 0,
"function_code_start": 3853,
"function_line_number": 94,
"function_code_length": 102,
"absolute_position": 184,
"caller_pc": 4279,
"caller_op": "JUMP",
"caller_file_index": 0,
"caller_line_number": 136,
"caller_code_start": 5630,
"caller_code_length": 21,
"call_type": "JUMPDEST",
"from": "0x6b175474e89094c44da98b954eedeac495271d0f",
"from_balance": null,
"to": "0x6b175474e89094c44da98b954eedeac495271d0f",
"to_balance": null,
"value": null,
"caller": {
"address": "0xe2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2",
"balance": "0"
},
"block_timestamp": "0001-01-01T00:00:00Z",
"gas": 7951356,
"gas_used": 62,
"input": "0x",
"decoded_input": [
{
"soltype": {
"name": "x",
"type": "uint256",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
"type": "uint"
}
},
"value": "5090814826520179690761462859"
},
{
"soltype": {
"name": "y",
"type": "uint256",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
"type": "uint"
}
},
"value": "2000000000000000000"
}
],
"output": "0x",
"decoded_output": [
{
"soltype": {
"name": "z",
"type": "uint256",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
"type": "uint"
}
},
"value": "5090814828520179690761462859"
}
],
"network_id": "",
"calls": null
}
]
},
"stack_trace": null,
"logs": [
{
"name": "Transfer",
"anonymous": false,
"inputs": [
{
"soltype": {
"name": "src",
"type": "address",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": true,
"simple_type": {
"type": "address"
}
},
"value": "0x0000000000000000000000000000000000000000"
},
{
"soltype": {
"name": "dst",
"type": "address",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": true,
"simple_type": {
"type": "address"
}
},
"value": "0xe58b9ee93700a616b50509c8292977fa7a0f8ce1"
},
{
"soltype": {
"name": "wad",
"type": "uint256",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
"type": "uint"
}
},
"value": "2000000000000000000"
}
],
"raw": {
"address": "0x6b175474e89094c44da98b954eedeac495271d0f",
"topics": [
"0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef",
"0x0000000000000000000000000000000000000000000000000000000000000000",
"0x000000000000000000000000e58b9ee93700a616b50509c8292977fa7a0f8ce1"
],
"data": "0x0000000000000000000000000000000000000000000000001bc16d674ec80000"
}
}
],
"balance_diff": null,
"nonce_diff": [
{
"address": "0xe2E2E2e2e2e2E2E2E2E2e2E2e2E2E2e2e2e2E2e2",
"original": "0",
"dirty": "1"
}
],
"state_diff": [
{
"address": "0x6b175474e89094c44da98b954eedeac495271d0f",
"soltype": {
"name": "totalSupply",
"type": "uint256",
"storage_location": "storage",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000001",
"indexed": false,
"simple_type": {
"type": "uint"
}
},
"original": "5090814826520179690761462859",
"dirty": "5090814828520179690761462859",
"raw": [
{
"address": "0x6b175474e89094c44da98b954eedeac495271d0f",
"key": "0x0000000000000000000000000000000000000000000000000000000000000001",
"original": "0x0000000000000000000000000000000000000000107305f8bb52a43b529da44b",
"dirty": "0x0000000000000000000000000000000000000000107305f8d71411a2a165a44b"
}
]
},
{
"address": "0x6b175474e89094c44da98b954eedeac495271d0f",
"soltype": {
"name": "balanceOf",
"type": "mapping (address => uint256)",
"storage_location": "storage",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000002",
"indexed": false
},
"original": {
"0xe58b9ee93700a616b50509c8292977fa7a0f8ce1": "0"
},
"dirty": {
"0xe58b9ee93700a616b50509c8292977fa7a0f8ce1": "2000000000000000000"
},
"raw": [
{
"address": "0x6b175474e89094c44da98b954eedeac495271d0f",
"key": "0x9b5472766fd311751f6a33c8e30061e20a26259ca626cf5a2feaadf96903cd9e",
"original": "0x0000000000000000000000000000000000000000000000000000000000000000",
"dirty": "0x0000000000000000000000000000000000000000000000001bc16d674ec80000"
}
]
}
],
"raw_state_diff": null,
"console_logs": null,
"created_at": "2023-02-10T13:04:56Z"
},
"method": "",
"decoded_input": null,
"call_trace": [
{
"call_type": "CALL",
"from": "0xe2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2",
"to": "0x6b175474e89094c44da98b954eedeac495271d0f",
"gas": 7978380,
"gas_used": 31845,
"type": "CALL",
"input": "0x40c10f19000000000000000000000000e58b9ee93700a616b50509c8292977fa7a0f8ce10000000000000000000000000000000000000000000000001bc16d674ec80000"
}
]
},
"simulation": {
"id": "46cb1f92-c9ee-4ef2-8736-6dc6ae84f8d8",
"project_id": "11686306-12f4-4c48-9396-c07dbe6b3c51",
"owner_id": "796e7d91-d8a2-4137-af6c-361f34e79557",
"network_id": "1",
"block_number": 16598541,
"transaction_index": 0,
"from": "0xe2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2",
"to": "0x6b175474e89094c44da98b954eedeac495271d0f",
"input": "0x40c10f19000000000000000000000000e58b9ee93700a616b50509c8292977fa7a0f8ce10000000000000000000000000000000000000000000000001bc16d674ec80000",
"gas": 8000000,
"gas_price": "0",
"gas_used": 53465,
"value": "0",
"method": "mint",
"status": true,
"access_list": null,
"queue_origin": "",
"block_header": {
"number": "0xfd460d",
"hash": "0x0000000000000000000000000000000000000000000000000000000000000000",
"stateRoot": "0x0000000000000000000000000000000000000000000000000000000000000000",
"parentHash": "0x033362dcc958b7c9628256b1a59d7a82c2a7205fc7cb7c3270d08aef8e760e52",
"sha3Uncles": "0x0000000000000000000000000000000000000000000000000000000000000000",
"transactionsRoot": "0x0000000000000000000000000000000000000000000000000000000000000000",
"receiptsRoot": "0x0000000000000000000000000000000000000000000000000000000000000000",
"logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
"timestamp": "0x63e640f8",
"difficulty": "0x0",
"gasLimit": "0x1c9c380",
"gasUsed": "0xed3d6a",
"miner": "0x0000000000000000000000000000000000000000",
"extraData": "0x",
"mixHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
"nonce": "0x0000000000000000",
"baseFeePerGas": "0x1",
"size": "0x0",
"totalDifficulty": "0x0",
"uncles": null,
"transactions": null
},
"state_overrides": {
"0x6b175474e89094c44da98b954eedeac495271d0f": {
"storage": {
"0xedd7d04419e9c48ceb6055956cbb4e2091ae310313a4d1fa7cbcfe7561616e03": "0x0000000000000000000000000000000000000000000000000000000000000001"
}
}
},
"mint": null,
"deposit_tx": false,
"system_tx": false,
"nonce": 0,
"addresses": [
"0xe2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2",
"0x6b175474e89094c44da98b954eedeac495271d0f"
],
"contract_ids": [
"eth:1:0xe2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2",
"eth:1:0x6b175474e89094c44da98b954eedeac495271d0f"
],
"created_at": "2023-02-10T13:04:57.004109816Z"
},
"contracts": [
{
"id": "eth:1:0x6b175474e89094c44da98b954eedeac495271d0f",
"contract_id": "eth:1:0x6b175474e89094c44da98b954eedeac495271d0f",
"balance": "",
"network_id": "1",
"public": true,
"export": false,
"verified_by": "etherscan",
"verification_date": null,
"address": "0x6b175474e89094c44da98b954eedeac495271d0f",
"contract_name": "Dai",
"ens_domain": null,
"type": "contract",
"standard": "erc20",
"standards": [
"erc20"
],
"token_data": {
"symbol": "DAI",
"name": "Dai Stablecoin",
"decimals": 18,
"main": true
},
"evm_version": "default",
"compiler_version": "v0.5.12+commit.7709ece9",
"optimizations_used": false,
"optimization_runs": 200,
"libraries": null,
"data": {
"main_contract": 0,
"contract_info": [
{
"id": 0,
"path": "Dai.sol",
"name": "Dai.sol",
"source": "// hevm: flattened sources of /nix/store/8xb41r4qd0cjb63wcrxf1qmfg88p0961-dss-6fd7de0/src/dai.sol\npragma solidity =0.5.12;\n\n////// /nix/store/8xb41r4qd0cjb63wcrxf1qmfg88p0961-dss-6fd7de0/src/lib.sol\n// This program is free software: you can redistribute it and/or modify\n// it under the terms of the GNU General Public License as published by\n// the Free Software Foundation, either version 3 of the License, or\n// (at your option) any later version.\n\n// This program is distributed in the hope that it will be useful,\n// but WITHOUT ANY WARRANTY; without even the implied warranty of\n// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the\n// GNU General Public License for more details.\n\n// You should have received a copy of the GNU General Public License\n// along with this program. If not, see <http://www.gnu.org/licenses/>.\n\n/* pragma solidity 0.5.12; */\n\ncontract LibNote {\n event LogNote(\n bytes4 indexed sig,\n address indexed usr,\n bytes32 indexed arg1,\n bytes32 indexed arg2,\n bytes data\n ) anonymous;\n\n modifier note {\n _;\n assembly {\n // log an 'anonymous' event with a constant 6 words of calldata\n // and four indexed topics: selector, caller, arg1 and arg2\n let mark := msize // end of memory ensures zero\n mstore(0x40, add(mark, 288)) // update free memory pointer\n mstore(mark, 0x20) // bytes type data offset\n mstore(add(mark, 0x20), 224) // bytes size (padded)\n calldatacopy(add(mark, 0x40), 0, 224) // bytes payload\n log4(mark, 288, // calldata\n shl(224, shr(224, calldataload(0))), // msg.sig\n caller, // msg.sender\n calldataload(4), // arg1\n calldataload(36) // arg2\n )\n }\n }\n}\n\n////// /nix/store/8xb41r4qd0cjb63wcrxf1qmfg88p0961-dss-6fd7de0/src/dai.sol\n// Copyright (C) 2017, 2018, 2019 dbrock, rain, mrchico\n\n// This program is free software: you can redistribute it and/or modify\n// it under the terms of the GNU Affero General Public License as published by\n// the Free Software Foundation, either version 3 of the License, or\n// (at your option) any later version.\n//\n// This program is distributed in the hope that it will be useful,\n// but WITHOUT ANY WARRANTY; without even the implied warranty of\n// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the\n// GNU Affero General Public License for more details.\n//\n// You should have received a copy of the GNU Affero General Public License\n// along with this program. If not, see <https://www.gnu.org/licenses/>.\n\n/* pragma solidity 0.5.12; */\n\n/* import \"./lib.sol\"; */\n\ncontract Dai is LibNote {\n // --- Auth ---\n mapping (address => uint) public wards;\n function rely(address guy) external note auth { wards[guy] = 1; }\n function deny(address guy) external note auth { wards[guy] = 0; }\n modifier auth {\n require(wards[msg.sender] == 1, \"Dai/not-authorized\");\n _;\n }\n\n // --- ERC20 Data ---\n string public constant name = \"Dai Stablecoin\";\n string public constant symbol = \"DAI\";\n string public constant version = \"1\";\n uint8 public constant decimals = 18;\n uint256 public totalSupply;\n\n mapping (address => uint) public balanceOf;\n mapping (address => mapping (address => uint)) public allowance;\n mapping (address => uint) public nonces;\n\n event Approval(address indexed src, address indexed guy, uint wad);\n event Transfer(address indexed src, address indexed dst, uint wad);\n\n // --- Math ---\n function add(uint x, uint y) internal pure returns (uint z) {\n require((z = x + y) >= x);\n }\n function sub(uint x, uint y) internal pure returns (uint z) {\n require((z = x - y) <= x);\n }\n\n // --- EIP712 niceties ---\n bytes32 public DOMAIN_SEPARATOR;\n // bytes32 public constant PERMIT_TYPEHASH = keccak256(\"Permit(address holder,address spender,uint256 nonce,uint256 expiry,bool allowed)\");\n bytes32 public constant PERMIT_TYPEHASH = 0xea2aa0a1be11a07ed86d755c93467f4f82362b452371d1ba94d1715123511acb;\n\n constructor(uint256 chainId_) public {\n wards[msg.sender] = 1;\n DOMAIN_SEPARATOR = keccak256(abi.encode(\n keccak256(\"EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)\"),\n keccak256(bytes(name)),\n keccak256(bytes(version)),\n chainId_,\n address(this)\n ));\n }\n\n // --- Token ---\n function transfer(address dst, uint wad) external returns (bool) {\n return transferFrom(msg.sender, dst, wad);\n }\n function transferFrom(address src, address dst, uint wad)\n public returns (bool)\n {\n require(balanceOf[src] >= wad, \"Dai/insufficient-balance\");\n if (src != msg.sender && allowance[src][msg.sender] != uint(-1)) {\n require(allowance[src][msg.sender] >= wad, \"Dai/insufficient-allowance\");\n allowance[src][msg.sender] = sub(allowance[src][msg.sender], wad);\n }\n balanceOf[src] = sub(balanceOf[src], wad);\n balanceOf[dst] = add(balanceOf[dst], wad);\n emit Transfer(src, dst, wad);\n return true;\n }\n function mint(address usr, uint wad) external auth {\n balanceOf[usr] = add(balanceOf[usr], wad);\n totalSupply = add(totalSupply, wad);\n emit Transfer(address(0), usr, wad);\n }\n function burn(address usr, uint wad) external {\n require(balanceOf[usr] >= wad, \"Dai/insufficient-balance\");\n if (usr != msg.sender && allowance[usr][msg.sender] != uint(-1)) {\n require(allowance[usr][msg.sender] >= wad, \"Dai/insufficient-allowance\");\n allowance[usr][msg.sender] = sub(allowance[usr][msg.sender], wad);\n }\n balanceOf[usr] = sub(balanceOf[usr], wad);\n totalSupply = sub(totalSupply, wad);\n emit Transfer(usr, address(0), wad);\n }\n function approve(address usr, uint wad) external returns (bool) {\n allowance[msg.sender][usr] = wad;\n emit Approval(msg.sender, usr, wad);\n return true;\n }\n\n // --- Alias ---\n function push(address usr, uint wad) external {\n transferFrom(msg.sender, usr, wad);\n }\n function pull(address usr, uint wad) external {\n transferFrom(usr, msg.sender, wad);\n }\n function move(address src, address dst, uint wad) external {\n transferFrom(src, dst, wad);\n }\n\n // --- Approve by signature ---\n function permit(address holder, address spender, uint256 nonce, uint256 expiry,\n bool allowed, uint8 v, bytes32 r, bytes32 s) external\n {\n bytes32 digest =\n keccak256(abi.encodePacked(\n \"\\x19\\x01\",\n DOMAIN_SEPARATOR,\n keccak256(abi.encode(PERMIT_TYPEHASH,\n holder,\n spender,\n nonce,\n expiry,\n allowed))\n ));\n\n require(holder != address(0), \"Dai/invalid-address-0\");\n require(holder == ecrecover(digest, v, r, s), \"Dai/invalid-permit\");\n require(expiry == 0 || now <= expiry, \"Dai/permit-expired\");\n require(nonce == nonces[holder]++, \"Dai/invalid-nonce\");\n uint wad = allowed ? uint(-1) : 0;\n allowance[holder][spender] = wad;\n emit Approval(holder, spender, wad);\n }\n}"
}
],
"abi": [
{
"type": "constructor",
"name": "",
"constant": false,
"anonymous": false,
"stateMutability": "",
"inputs": [
{
"name": "chainId_",
"type": "uint256",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
"type": "uint"
}
}
],
"outputs": null
},
{
"type": "function",
"name": "totalSupply",
"constant": true,
"anonymous": false,
"stateMutability": "view",
"inputs": [],
"outputs": [
{
"name": "",
"type": "uint256",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
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}
}
]
},
{
"type": "function",
"name": "move",
"constant": false,
"anonymous": false,
"stateMutability": "nonpayable",
"inputs": [
{
"name": "src",
"type": "address",
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"components": null,
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},
{
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"components": null,
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},
{
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"components": null,
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"indexed": false,
"simple_type": {
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}
}
],
"outputs": []
},
{
"type": "function",
"name": "name",
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"outputs": [
{
"name": "",
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}
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},
{
"type": "function",
"name": "wards",
"constant": true,
"anonymous": false,
"stateMutability": "view",
"inputs": [
{
"name": "",
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}
]
},
{
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"inputs": [
{
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{
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],
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}
]
},
{
"type": "function",
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"constant": false,
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"inputs": [
{
"name": "usr",
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},
{
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"components": null,
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"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
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}
}
],
"outputs": []
},
{
"type": "function",
"name": "transferFrom",
"constant": false,
"anonymous": false,
"stateMutability": "nonpayable",
"inputs": [
{
"name": "src",
"type": "address",
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"indexed": false,
"simple_type": {
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},
{
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},
{
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"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
"type": "uint"
}
}
],
"outputs": [
{
"name": "",
"type": "bool",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
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}
}
]
},
{
"type": "function",
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"constant": false,
"anonymous": false,
"stateMutability": "nonpayable",
"inputs": [
{
"name": "usr",
"type": "address",
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"components": null,
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"indexed": false,
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}
},
{
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"components": null,
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"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
"type": "uint"
}
}
],
"outputs": []
},
{
"type": "function",
"name": "deny",
"constant": false,
"anonymous": false,
"stateMutability": "nonpayable",
"inputs": [
{
"name": "guy",
"type": "address",
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"components": null,
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"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
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}
}
],
"outputs": []
},
{
"type": "function",
"name": "push",
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"anonymous": false,
"stateMutability": "nonpayable",
"inputs": [
{
"name": "usr",
"type": "address",
"storage_location": "default",
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},
{
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"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
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}
}
],
"outputs": []
},
{
"type": "function",
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{
"name": "",
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}
}
],
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"simple_type": {
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}
}
]
},
{
"type": "function",
"name": "symbol",
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"stateMutability": "view",
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"outputs": [
{
"name": "",
"type": "string",
"storage_location": "default",
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"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
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"simple_type": {
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}
}
]
},
{
"type": "function",
"name": "allowance",
"constant": true,
"anonymous": false,
"stateMutability": "view",
"inputs": [
{
"name": "",
"type": "address",
"storage_location": "default",
"components": null,
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"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
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},
{
"name": "",
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"components": null,
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"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
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}
}
],
"outputs": [
{
"name": "",
"type": "uint256",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
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}
}
]
},
{
"type": "function",
"name": "balanceOf",
"constant": true,
"anonymous": false,
"stateMutability": "view",
"inputs": [
{
"name": "",
"type": "address",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
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"simple_type": {
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}
}
],
"outputs": [
{
"name": "",
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"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
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}
}
]
},
{
"type": "function",
"name": "version",
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"anonymous": false,
"stateMutability": "view",
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"outputs": [
{
"name": "",
"type": "string",
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"components": null,
"offset": 0,
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"indexed": false,
"simple_type": {
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}
}
]
},
{
"type": "function",
"name": "PERMIT_TYPEHASH",
"constant": true,
"anonymous": false,
"stateMutability": "view",
"inputs": [],
"outputs": [
{
"name": "",
"type": "bytes32",
"storage_location": "default",
"components": null,
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"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
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"simple_type": {
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}
]
},
{
"type": "function",
"name": "transfer",
"constant": false,
"anonymous": false,
"stateMutability": "nonpayable",
"inputs": [
{
"name": "dst",
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"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
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},
{
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"components": null,
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"simple_type": {
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}
],
"outputs": [
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}
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},
{
"type": "function",
"name": "decimals",
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"stateMutability": "view",
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{
"name": "",
"type": "uint8",
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}
]
},
{
"type": "function",
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{
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}
]
},
{
"type": "function",
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"stateMutability": "nonpayable",
"inputs": [
{
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},
{
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},
{
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},
{
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},
{
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},
{
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{
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},
{
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}
],
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},
{
"type": "function",
"name": "pull",
"constant": false,
"anonymous": false,
"stateMutability": "nonpayable",
"inputs": [
{
"name": "usr",
"type": "address",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
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}
},
{
"name": "wad",
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"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
"type": "uint"
}
}
],
"outputs": []
},
{
"type": "function",
"name": "rely",
"constant": false,
"anonymous": false,
"stateMutability": "nonpayable",
"inputs": [
{
"name": "guy",
"type": "address",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
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}
],
"outputs": []
},
{
"type": "event",
"name": "Approval",
"constant": false,
"anonymous": false,
"stateMutability": "",
"inputs": [
{
"name": "src",
"type": "address",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": true,
"simple_type": {
"type": "address"
}
},
{
"name": "guy",
"type": "address",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": true,
"simple_type": {
"type": "address"
}
},
{
"name": "wad",
"type": "uint256",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
"type": "uint"
}
}
],
"outputs": null
},
{
"type": "event",
"name": "LogNote",
"constant": false,
"anonymous": true,
"stateMutability": "",
"inputs": [
{
"name": "sig",
"type": "bytes4",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": true,
"simple_type": {
"type": "bytes"
}
},
{
"name": "usr",
"type": "address",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": true,
"simple_type": {
"type": "address"
}
},
{
"name": "arg1",
"type": "bytes32",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": true,
"simple_type": {
"type": "bytes"
}
},
{
"name": "arg2",
"type": "bytes32",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": true,
"simple_type": {
"type": "bytes"
}
},
{
"name": "data",
"type": "bytes",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
"type": "bytes"
}
}
],
"outputs": null
},
{
"type": "event",
"name": "Transfer",
"constant": false,
"anonymous": false,
"stateMutability": "",
"inputs": [
{
"name": "src",
"type": "address",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": true,
"simple_type": {
"type": "address"
}
},
{
"name": "dst",
"type": "address",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": true,
"simple_type": {
"type": "address"
}
},
{
"name": "wad",
"type": "uint256",
"storage_location": "default",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false,
"simple_type": {
"type": "uint"
}
}
],
"outputs": null
}
],
"raw_abi": null,
"states": [
{
"name": "DOMAIN_SEPARATOR",
"type": "bytes32",
"storage_location": "storage",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000005",
"indexed": false,
"simple_type": {
"type": "bytes"
}
},
{
"name": "wards",
"type": "mapping (address => uint256)",
"storage_location": "storage",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000000",
"indexed": false
},
{
"name": "totalSupply",
"type": "uint256",
"storage_location": "storage",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000001",
"indexed": false,
"simple_type": {
"type": "uint"
}
},
{
"name": "balanceOf",
"type": "mapping (address => uint256)",
"storage_location": "storage",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000002",
"indexed": false
},
{
"name": "allowance",
"type": "mapping (address => mapping (address => uint256))",
"storage_location": "storage",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000003",
"indexed": false
},
{
"name": "nonces",
"type": "mapping (address => uint256)",
"storage_location": "storage",
"components": null,
"offset": 0,
"index": "0x0000000000000000000000000000000000000000000000000000000000000004",
"indexed": false
}
]
},
"creation_block": 0,
"creation_tx": "",
"creator_address": "",
"created_at": "2022-12-16T09:10:37Z",
"number_of_watches": null,
"language": "solidity",
"in_project": false,
"number_of_files": 1
}
],
"generated_access_list": []
}
Storage Slot Calculation
The key part of setting an override is calculating the correct storage location. This depends on the structure of the contract’s storage and the specific variable you want to override. For the DAI contract, the storage location for thewards mapping for our address is calculated based on the Solidity storage layout rules, and is given by this expression:
example.js
const fakeWardAddress = '0xe2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2';
const overrideStorageLocation = keccak256(
concatenate(
hexZeroPad(fakeWardAddress), hexZeroPad(0x0)
)
)
0xedd7d04419e9c48ceb6055956cbb4e2091ae310313a4d1fa7cbcfe7561616e03.