pragma solidity ^0.5.0; /** * @dev Collection of functions related to the address type, */ library Address { /** * @dev Returns true if `account` is a contract. * * This test is non-exhaustive, and there may be false-negatives: during the * execution of a contract's constructor, its address will be reported as * not containing a contract. * * > It is unsafe to assume that an address for which this function returns * false is an externally-owned account (EOA) and not a contract. */ function isContract(address account) internal view returns (bool) { // This method relies in extcodesize, which returns 0 for contracts in // construction, since the code is only stored at the end of the // constructor execution. uint256 size; // solhint-disable-next-line no-inline-assembly assembly { size := extcodesize(account) } return size > 0; } }