solidity/test/compilationTests/gnosis/Oracles/DifficultyOracle.sol
2020-07-07 12:16:18 +02:00

65 lines
1.5 KiB
Solidity

pragma solidity >=0.0;
import "../Oracles/Oracle.sol";
/// @title Difficulty oracle contract - Oracle to resolve difficulty events at given block
/// @author Stefan George - <stefan@gnosis.pm>
contract DifficultyOracle is Oracle {
/*
* Events
*/
event OutcomeAssignment(uint difficulty);
/*
* Storage
*/
uint public blockNumber;
uint public difficulty;
/*
* Public functions
*/
/// @dev Contract constructor validates and sets target block number
/// @param _blockNumber Target block number
constructor(uint _blockNumber)
{
// Block has to be in the future
require(_blockNumber > block.number);
blockNumber = _blockNumber;
}
/// @dev Sets difficulty as winning outcome for specified block
function setOutcome()
public
{
// Block number was reached and outcome was not set yet
require(block.number >= blockNumber && difficulty == 0);
difficulty = block.difficulty;
emit OutcomeAssignment(difficulty);
}
/// @dev Returns if difficulty is set
/// @return Is outcome set?
function isOutcomeSet()
public
override
view
returns (bool)
{
// Difficulty is always bigger than 0
return difficulty > 0;
}
/// @dev Returns difficulty
/// @return Outcome
function getOutcome()
public
override
view
returns (int)
{
return int(difficulty);
}
}