codex-contracts-eth/contracts/Proofs.sol

118 lines
3.9 KiB
Solidity

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.8;
import "./Configuration.sol";
import "./Requests.sol";
import "./Periods.sol";
abstract contract Proofs is Periods {
ProofConfig private _config;
constructor(ProofConfig memory config) Periods(config.period) {
require(block.number > 256, "Insufficient block height");
_config = config;
}
mapping(SlotId => uint256) private _slotStarts;
mapping(SlotId => uint256) private _probabilities;
mapping(SlotId => uint256) private _missed;
mapping(SlotId => mapping(Period => bool)) private _received;
mapping(SlotId => mapping(Period => bool)) private _missing;
function slotState(SlotId id) public view virtual returns (SlotState);
function missingProofs(SlotId slotId) public view returns (uint256) {
return _missed[slotId];
}
function _startRequiringProofs(SlotId id, uint256 probability) internal {
_slotStarts[id] = block.timestamp;
_probabilities[id] = probability;
}
function _getPointer(SlotId id, Period period) internal view returns (uint8) {
uint256 blockNumber = block.number % 256;
uint256 periodNumber = Period.unwrap(period) % 256;
uint256 idOffset = uint256(SlotId.unwrap(id)) % 256;
uint256 pointer = (blockNumber + periodNumber + idOffset) % 256;
return uint8(pointer);
}
function getPointer(SlotId id) public view returns (uint8) {
return _getPointer(id, _blockPeriod());
}
function _getChallenge(uint8 pointer) internal view returns (bytes32) {
bytes32 hash = blockhash(block.number - 1 - pointer);
assert(uint256(hash) != 0);
return keccak256(abi.encode(hash));
}
function _getChallenge(
SlotId id,
Period period
) internal view returns (bytes32) {
return _getChallenge(_getPointer(id, period));
}
function getChallenge(SlotId id) public view returns (bytes32) {
return _getChallenge(id, _blockPeriod());
}
function _getProofRequirement(
SlotId id,
Period period
) internal view returns (bool isRequired, uint8 pointer) {
SlotState state = slotState(id);
Period start = _periodOf(_slotStarts[id]);
if (state != SlotState.Filled || !_isAfter(period, start)) {
return (false, 0);
}
pointer = _getPointer(id, period);
bytes32 challenge = _getChallenge(pointer);
uint256 probability = (_probabilities[id] * (256 - _config.downtime)) / 256;
isRequired = uint256(challenge) % probability == 0;
}
function _isProofRequired(
SlotId id,
Period period
) internal view returns (bool) {
bool isRequired;
uint8 pointer;
(isRequired, pointer) = _getProofRequirement(id, period);
return isRequired && pointer >= _config.downtime;
}
function isProofRequired(SlotId id) public view returns (bool) {
return _isProofRequired(id, _blockPeriod());
}
function willProofBeRequired(SlotId id) public view returns (bool) {
bool isRequired;
uint8 pointer;
(isRequired, pointer) = _getProofRequirement(id, _blockPeriod());
return isRequired && pointer < _config.downtime;
}
function submitProof(SlotId id, bytes calldata proof) public {
require(proof.length > 0, "Invalid proof"); // TODO: replace by actual check
require(!_received[id][_blockPeriod()], "Proof already submitted");
_received[id][_blockPeriod()] = true;
emit ProofSubmitted(id, proof);
}
function _markProofAsMissing(SlotId id, Period missedPeriod) internal {
uint256 end = _periodEnd(missedPeriod);
require(end < block.timestamp, "Period has not ended yet");
require(block.timestamp < end + _config.timeout, "Validation timed out");
require(!_received[id][missedPeriod], "Proof was submitted, not missing");
require(_isProofRequired(id, missedPeriod), "Proof was not required");
require(!_missing[id][missedPeriod], "Proof already marked as missing");
_missing[id][missedPeriod] = true;
_missed[id] += 1;
}
event ProofSubmitted(SlotId id, bytes proof);
}