dagger-contracts/contracts/Proofs.sol

129 lines
4.2 KiB
Solidity

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.8;
import "./Requests.sol";
import "./Periods.sol";
abstract contract Proofs is Periods {
uint256 public immutable proofTimeout;
uint8 private immutable downtime;
constructor(
uint256 __period,
uint256 __timeout,
uint8 __downtime
) Periods(__period) {
require(block.number > 256, "Insufficient block height");
proofTimeout = __timeout;
downtime = __downtime;
}
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) internal view virtual returns (SlotState);
function missingProofs(SlotId slotId) public view returns (uint256) {
return missed[slotId];
}
/// @notice Informs the contract that proofs should be expected for id
/// @dev Requires that the id is not already in use
/// @param probability The probability that a proof should be expected
function _startRequiringProofs(SlotId id, uint256 probability) internal {
slotStarts[id] = block.timestamp;
probabilities[id] = probability;
}
function _getPointer(
SlotId id,
Period proofPeriod
) internal view returns (uint8) {
uint256 blockNumber = block.number % 256;
uint256 periodNumber = Period.unwrap(proofPeriod) % 256;
uint256 idOffset = uint256(SlotId.unwrap(id)) % 256;
uint256 pointer = (blockNumber + periodNumber + idOffset) % 256;
return uint8(pointer);
}
function _getPointer(SlotId id) internal 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 proofPeriod
) internal view returns (bytes32) {
return _getChallenge(_getPointer(id, proofPeriod));
}
function _getChallenge(SlotId id) internal view returns (bytes32) {
return _getChallenge(id, blockPeriod());
}
function _getProofRequirement(
SlotId id,
Period proofPeriod
) internal view returns (bool isRequired, uint8 pointer) {
SlotState state = slotState(id);
Period start = periodOf(slotStarts[id]);
if (state != SlotState.Filled || !isAfter(proofPeriod, start)) {
return (false, 0);
}
pointer = _getPointer(id, proofPeriod);
bytes32 challenge = _getChallenge(pointer);
uint256 probability = (probabilities[id] * (256 - downtime)) / 256;
isRequired = uint256(challenge) % probability == 0;
}
function _isProofRequired(
SlotId id,
Period proofPeriod
) internal view returns (bool) {
bool isRequired;
uint8 pointer;
(isRequired, pointer) = _getProofRequirement(id, proofPeriod);
return isRequired && pointer >= downtime;
}
function _isProofRequired(SlotId id) internal view returns (bool) {
return _isProofRequired(id, blockPeriod());
}
function _willProofBeRequired(SlotId id) internal view returns (bool) {
bool isRequired;
uint8 pointer;
(isRequired, pointer) = _getProofRequirement(id, blockPeriod());
return isRequired && pointer < 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 periodEnd = periodEnd(missedPeriod);
require(periodEnd < block.timestamp, "Period has not ended yet");
require(block.timestamp < periodEnd + proofTimeout, "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);
}