Contract Source Code:
File 1 of 1 : ulluToken
// File: openzeppelin-solidity/contracts/math/SafeMath.sol
pragma solidity >=0.4.21 <0.7.0;
/**
* @dev Wrappers over Solidity's arithmetic operations with added overflow
* checks.
*
* Arithmetic operations in Solidity wrap on overflow. This can easily result
* in bugs, because programmers usually assume that an overflow raises an
* error, which is the standard behavior in high level programming languages.
* `SafeMath` restores this intuition by reverting the transaction when an
* operation overflows.
*
* Using this library instead of the unchecked operations eliminates an entire
* class of bugs, so it's recommended to use it always.
*/
library SafeMath {
/**
* @dev Returns the addition of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `+` operator.
*
* Requirements:
* - Addition cannot overflow.
*/
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
require(c >= a, "SafeMath: addition overflow");
return c;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting on
* overflow (when the result is negative).
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
* - Subtraction cannot overflow.
*/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
return sub(a, b, "SafeMath: subtraction overflow");
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on
* overflow (when the result is negative).
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
* - Subtraction cannot overflow.
*
* _Available since v2.4.0._
*/
function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b <= a, errorMessage);
uint256 c = a - b;
return c;
}
/**
* @dev Returns the multiplication of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `*` operator.
*
* Requirements:
* - Multiplication cannot overflow.
*/
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the
// benefit is lost if 'b' is also tested.
// See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
if (a == 0) {
return 0;
}
uint256 c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
return c;
}
/**
* @dev Returns the integer division of two unsigned integers. Reverts on
* division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
* - The divisor cannot be zero.
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
return div(a, b, "SafeMath: division by zero");
}
/**
* @dev Returns the integer division of two unsigned integers. Reverts with custom message on
* division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
* - The divisor cannot be zero.
*
* _Available since v2.4.0._
*/
function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
// Solidity only automatically asserts when dividing by 0
require(b > 0, errorMessage);
uint256 c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
return c;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* Reverts when dividing by zero.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
* - The divisor cannot be zero.
*/
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
return mod(a, b, "SafeMath: modulo by zero");
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* Reverts with custom message when dividing by zero.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
* - The divisor cannot be zero.
*
* _Available since v2.4.0._
*/
function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b != 0, errorMessage);
return a % b;
}
}
// File: openzeppelin-solidity/contracts/GSN/Context.sol
/*
* @dev Provides information about the current execution context, including the
* sender of the transaction and its data. While these are generally available
* via msg.sender and msg.data, they should not be accessed in such a direct
* manner, since when dealing with GSN meta-transactions the account sending and
* paying for execution may not be the actual sender (as far as an application
* is concerned).
*
* This contract is only required for intermediate, library-like contracts.
*/
contract Context {
// Empty internal constructor, to prevent people from mistakenly deploying
// an instance of this contract, which should be used via inheritance.
constructor () internal { }
// solhint-disable-previous-line no-empty-blocks
function _msgSender() internal view returns (address payable) {
return msg.sender;
}
function _msgData() internal view returns (bytes memory) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}
// File: openzeppelin-solidity/contracts/token/ERC20/IERC20.sol
/**
* @dev Interface of the ERC20 standard as defined in the EIP. Does not include
* the optional functions; to access them see {ERC20Detailed}.
*/
interface IERC20 {
/**
* @dev Returns the amount of tokens in existence.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/
function balanceOf(address account) external view returns (uint256);
/**
* @dev Moves `amount` tokens from the caller's account to `recipient`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address recipient, uint256 amount) external returns (bool);
/**
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* zero by default.
*
* This value changes when {approve} or {transferFrom} are called.
*/
function allowance(address owner, address spender) external view returns (uint256);
/**
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* IMPORTANT: Beware that changing an allowance with this method brings the risk
* that someone may use both the old and the new allowance by unfortunate
* transaction ordering. One possible solution to mitigate this race
* condition is to first reduce the spender's allowance to 0 and set the
* desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
*
* Emits an {Approval} event.
*/
function approve(address spender, uint256 amount) external returns (bool);
/**
* @dev Moves `amount` tokens from `sender` to `recipient` using the
* allowance mechanism. `amount` is then deducted from the caller's
* allowance.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/
event Transfer(address indexed from, address indexed to, uint256 value);
/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to {approve}. `value` is the new allowance.
*/
event Approval(address indexed owner, address indexed spender, uint256 value);
}
// File: openzeppelin-solidity/contracts/utils/Address.sol
/**
* @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.
*
* IMPORTANT: 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.
// According to EIP-1052, 0x0 is the value returned for not-yet created accounts
// and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
// for accounts without code, i.e. `keccak256('')`
bytes32 codehash;
bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
// solhint-disable-next-line no-inline-assembly
assembly { codehash := extcodehash(account) }
return (codehash != 0x0 && codehash != accountHash);
}
/**
* @dev Converts an `address` into `address payable`. Note that this is
* simply a type cast: the actual underlying value is not changed.
*
* _Available since v2.4.0._
*/
function toPayable(address account) internal pure returns (address payable) {
return address(uint160(account));
}
/**
* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
* `recipient`, forwarding all available gas and reverting on errors.
*
* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
* of certain opcodes, possibly making contracts go over the 2300 gas limit
* imposed by `transfer`, making them unable to receive funds via
* `transfer`. {sendValue} removes this limitation.
*
* https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
*
* IMPORTANT: because control is transferred to `recipient`, care must be
* taken to not create reentrancy vulnerabilities. Consider using
* {ReentrancyGuard} or the
* https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
*
* _Available since v2.4.0._
*/
function sendValue(address payable recipient, uint256 amount) internal {
require(address(this).balance >= amount, "Address: insufficient balance");
// solhint-disable-next-line avoid-call-value
(bool success, ) = recipient.call.value(amount)("");
require(success, "Address: unable to send value, recipient may have reverted");
}
}
// File: openzeppelin-solidity/contracts/token/ERC20/SafeERC20.sol
/**
* @title SafeERC20
* @dev Wrappers around ERC20 operations that throw on failure (when the token
* contract returns false). Tokens that return no value (and instead revert or
* throw on failure) are also supported, non-reverting calls are assumed to be
* successful.
* To use this library you can add a `using SafeERC20 for ERC20;` statement to your contract,
* which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
*/
library SafeERC20 {
using SafeMath for uint256;
using Address for address;
function safeTransfer(IERC20 token, address to, uint256 value) internal {
callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
}
function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
}
function safeApprove(IERC20 token, address spender, uint256 value) internal {
// safeApprove should only be called when setting an initial allowance,
// or when resetting it to zero. To increase and decrease it, use
// 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
// solhint-disable-next-line max-line-length
require((value == 0) || (token.allowance(address(this), spender) == 0),
"SafeERC20: approve from non-zero to non-zero allowance"
);
callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
}
function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
uint256 newAllowance = token.allowance(address(this), spender).add(value);
callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
/**
* @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
* on the return value: the return value is optional (but if data is returned, it must not be false).
* @param token The token targeted by the call.
* @param data The call data (encoded using abi.encode or one of its variants).
*/
function callOptionalReturn(IERC20 token, bytes memory data) private {
// We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
// we're implementing it ourselves.
// A Solidity high level call has three parts:
// 1. The target address is checked to verify it contains contract code
// 2. The call itself is made, and success asserted
// 3. The return value is decoded, which in turn checks the size of the returned data.
// solhint-disable-next-line max-line-length
require(address(token).isContract(), "SafeERC20: call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = address(token).call(data);
require(success, "SafeERC20: low-level call failed");
if (returndata.length > 0) { // Return data is optional
// solhint-disable-next-line max-line-length
require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
}
}
}
// File: openzeppelin-solidity/contracts/utils/ReentrancyGuard.sol
/**
* @dev Contract module that helps prevent reentrant calls to a function.
*
* Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
* available, which can be applied to functions to make sure there are no nested
* (reentrant) calls to them.
*
* Note that because there is a single `nonReentrant` guard, functions marked as
* `nonReentrant` may not call one another. This can be worked around by making
* those functions `private`, and then adding `external` `nonReentrant` entry
* points to them.
*/
contract ReentrancyGuard {
// counter to allow mutex lock with only one SSTORE operation
uint256 private _guardCounter;
constructor () internal {
// The counter starts at one to prevent changing it from zero to a non-zero
// value, which is a more expensive operation.
_guardCounter = 1;
}
/**
* @dev Prevents a contract from calling itself, directly or indirectly.
* Calling a `nonReentrant` function from another `nonReentrant`
* function is not supported. It is possible to prevent this from happening
* by making the `nonReentrant` function external, and make it call a
* `private` function that does the actual work.
*/
modifier nonReentrant() {
_guardCounter += 1;
uint256 localCounter = _guardCounter;
_;
require(localCounter == _guardCounter, "ReentrancyGuard: reentrant call");
}
}
// File: openzeppelin-solidity/contracts/crowdsale/Crowdsale.sol
/**
* @title Crowdsale
* @dev Crowdsale is a base contract for managing a token crowdsale,
* allowing investors to purchase tokens with ether. This contract implements
* such functionality in its most fundamental form and can be extended to provide additional
* functionality and/or custom behavior.
* The external interface represents the basic interface for purchasing tokens, and conforms
* the base architecture for crowdsales. It is *not* intended to be modified / overridden.
* The internal interface conforms the extensible and modifiable surface of crowdsales. Override
* the methods to add functionality. Consider using 'super' where appropriate to concatenate
* behavior.
*/
contract Crowdsale is Context, ReentrancyGuard {
using SafeMath for uint256;
using SafeERC20 for IERC20;
// The token being sold
IERC20 private _token;
// Address where funds are collected
address payable private _wallet;
// How many token units a buyer gets per wei.
// The rate is the conversion between wei and the smallest and indivisible token unit.
// So, if you are using a rate of 1 with a ERC20Detailed token with 3 decimals called TOK
// 1 wei will give you 1 unit, or 0.001 TOK.
uint256 private _rate;
// Amount of wei raised
uint256 private _weiRaised;
/**
* Event for token purchase logging
* @param purchaser who paid for the tokens
* @param beneficiary who got the tokens
* @param value weis paid for purchase
* @param amount amount of tokens purchased
*/
event TokensPurchased(address indexed purchaser, address indexed beneficiary, uint256 value, uint256 amount);
/**
* @param rate Number of token units a buyer gets per wei
* @dev The rate is the conversion between wei and the smallest and indivisible
* token unit. So, if you are using a rate of 1 with a ERC20Detailed token
* with 3 decimals called TOK, 1 wei will give you 1 unit, or 0.001 TOK.
* @param wallet Address where collected funds will be forwarded to
* @param token Address of the token being sold
*/
constructor (uint256 rate, address payable wallet, IERC20 token) public {
require(rate > 0, "Crowdsale: rate is 0");
require(wallet != address(0), "Crowdsale: wallet is the zero address");
require(address(token) != address(0), "Crowdsale: token is the zero address");
_rate = rate;
_wallet = wallet;
_token = token;
}
/**
* @dev fallback function ***DO NOT OVERRIDE***
* Note that other contracts will transfer funds with a base gas stipend
* of 2300, which is not enough to call buyTokens. Consider calling
* buyTokens directly when purchasing tokens from a contract.
*/
function () external payable {
buyTokens(_msgSender());
}
/**
* @return the token being sold.
*/
function token() public view returns (IERC20) {
return _token;
}
/**
* @return the address where funds are collected.
*/
function wallet() public view returns (address payable) {
return _wallet;
}
/**
* @return the number of token units a buyer gets per wei.
*/
function rate() public view returns (uint256) {
return _rate;
}
/**
* @return the amount of wei raised.
*/
function weiRaised() public view returns (uint256) {
return _weiRaised;
}
/**
* @dev low level token purchase ***DO NOT OVERRIDE***
* This function has a non-reentrancy guard, so it shouldn't be called by
* another `nonReentrant` function.
* @param beneficiary Recipient of the token purchase
*/
function buyTokens(address beneficiary) public nonReentrant payable {
uint256 weiAmount = msg.value;
_preValidatePurchase(beneficiary, weiAmount);
// calculate token amount to be created
uint256 tokens = _getTokenAmount(weiAmount);
// update state
_weiRaised = _weiRaised.add(weiAmount);
_processPurchase(beneficiary, tokens);
emit TokensPurchased(_msgSender(), beneficiary, weiAmount, tokens);
_updatePurchasingState(beneficiary, weiAmount);
_forwardFunds();
_postValidatePurchase(beneficiary, weiAmount);
}
/**
* @dev Validation of an incoming purchase. Use require statements to revert state when conditions are not met.
* Use `super` in contracts that inherit from Crowdsale to extend their validations.
* Example from CappedCrowdsale.sol's _preValidatePurchase method:
* super._preValidatePurchase(beneficiary, weiAmount);
* require(weiRaised().add(weiAmount) <= cap);
* @param beneficiary Address performing the token purchase
* @param weiAmount Value in wei involved in the purchase
*/
function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal view {
require(beneficiary != address(0), "Crowdsale: beneficiary is the zero address");
require(weiAmount != 0, "Crowdsale: weiAmount is 0");
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
}
/**
* @dev Validation of an executed purchase. Observe state and use revert statements to undo rollback when valid
* conditions are not met.
* @param beneficiary Address performing the token purchase
* @param weiAmount Value in wei involved in the purchase
*/
function _postValidatePurchase(address beneficiary, uint256 weiAmount) internal view {
// solhint-disable-previous-line no-empty-blocks
}
/**
* @dev Source of tokens. Override this method to modify the way in which the crowdsale ultimately gets and sends
* its tokens.
* @param beneficiary Address performing the token purchase
* @param tokenAmount Number of tokens to be emitted
*/
function _deliverTokens(address beneficiary, uint256 tokenAmount) internal {
_token.safeTransfer(beneficiary, tokenAmount);
}
/**
* @dev Executed when a purchase has been validated and is ready to be executed. Doesn't necessarily emit/send
* tokens.
* @param beneficiary Address receiving the tokens
* @param tokenAmount Number of tokens to be purchased
*/
function _processPurchase(address beneficiary, uint256 tokenAmount) internal {
_deliverTokens(beneficiary, tokenAmount);
}
/**
* @dev Override for extensions that require an internal state to check for validity (current user contributions,
* etc.)
* @param beneficiary Address receiving the tokens
* @param weiAmount Value in wei involved in the purchase
*/
function _updatePurchasingState(address beneficiary, uint256 weiAmount) internal {
// solhint-disable-previous-line no-empty-blocks
}
/**
* @dev Override to extend the way in which ether is converted to tokens.
* @param weiAmount Value in wei to be converted into tokens
* @return Number of tokens that can be purchased with the specified _weiAmount
*/
function _getTokenAmount(uint256 weiAmount) internal view returns (uint256) {
return weiAmount.mul(_rate);
}
/**
* @dev Determines how ETH is stored/forwarded on purchases.
*/
function _forwardFunds() internal {
_wallet.transfer(msg.value);
}
}
// File: openzeppelin-solidity/contracts/crowdsale/validation/CappedCrowdsale.sol
/**
* @title CappedCrowdsale
* @dev Crowdsale with a limit for total contributions.
*/
contract CappedCrowdsale is Crowdsale {
using SafeMath for uint256;
uint256 private _cap;
/**
* @dev Constructor, takes maximum amount of wei accepted in the crowdsale.
* @param cap Max amount of wei to be contributed
*/
constructor (uint256 cap) public {
require(cap > 0, "CappedCrowdsale: cap is 0");
_cap = cap;
}
/**
* @return the cap of the crowdsale.
*/
function cap() public view returns (uint256) {
return _cap;
}
/**
* @dev Checks whether the cap has been reached.
* @return Whether the cap was reached
*/
function capReached() public view returns (bool) {
return weiRaised() >= _cap;
}
/**
* @dev Extend parent behavior requiring purchase to respect the funding cap.
* @param beneficiary Token purchaser
* @param weiAmount Amount of wei contributed
*/
function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal view {
super._preValidatePurchase(beneficiary, weiAmount);
require(weiRaised().add(weiAmount) <= _cap, "CappedCrowdsale: cap exceeded");
}
}
// File: openzeppelin-solidity/contracts/crowdsale/validation/TimedCrowdsale.sol
/**
* @title TimedCrowdsale
* @dev Crowdsale accepting contributions only within a time frame.
*/
contract TimedCrowdsale is Crowdsale {
using SafeMath for uint256;
uint256 private _openingTime;
uint256 private _closingTime;
/**
* Event for crowdsale extending
* @param newClosingTime new closing time
* @param prevClosingTime old closing time
*/
event TimedCrowdsaleExtended(uint256 prevClosingTime, uint256 newClosingTime);
/**
* @dev Reverts if not in crowdsale time range.
*/
modifier onlyWhileOpen {
require(isOpen(), "TimedCrowdsale: not open");
_;
}
/**
* @dev Constructor, takes crowdsale opening and closing times.
* @param openingTime Crowdsale opening time
* @param closingTime Crowdsale closing time
*/
constructor (uint256 openingTime, uint256 closingTime) public {
// solhint-disable-next-line not-rely-on-time
require(openingTime >= block.timestamp, "TimedCrowdsale: opening time is before current time");
// solhint-disable-next-line max-line-length
require(closingTime > openingTime, "TimedCrowdsale: opening time is not before closing time");
_openingTime = openingTime;
_closingTime = closingTime;
}
/**
* @return the crowdsale opening time.
*/
function openingTime() public view returns (uint256) {
return _openingTime;
}
/**
* @return the crowdsale closing time.
*/
function closingTime() public view returns (uint256) {
return _closingTime;
}
/**
* @return true if the crowdsale is open, false otherwise.
*/
function isOpen() public view returns (bool) {
// solhint-disable-next-line not-rely-on-time
return block.timestamp >= _openingTime && block.timestamp <= _closingTime;
}
/**
* @dev Checks whether the period in which the crowdsale is open has already elapsed.
* @return Whether crowdsale period has elapsed
*/
function hasClosed() public view returns (bool) {
// solhint-disable-next-line not-rely-on-time
return block.timestamp > _closingTime;
}
/**
* @dev Extend parent behavior requiring to be within contributing period.
* @param beneficiary Token purchaser
* @param weiAmount Amount of wei contributed
*/
function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal onlyWhileOpen view {
super._preValidatePurchase(beneficiary, weiAmount);
}
/**
* @dev Extend crowdsale.
* @param newClosingTime Crowdsale closing time
*/
function _extendTime(uint256 newClosingTime) internal {
require(!hasClosed(), "TimedCrowdsale: already closed");
// solhint-disable-next-line max-line-length
require(newClosingTime > _closingTime, "TimedCrowdsale: new closing time is before current closing time");
emit TimedCrowdsaleExtended(_closingTime, newClosingTime);
_closingTime = newClosingTime;
}
}
// File: openzeppelin-solidity/contracts/crowdsale/distribution/FinalizableCrowdsale.sol
/**
* @title FinalizableCrowdsale
* @dev Extension of TimedCrowdsale with a one-off finalization action, where one
* can do extra work after finishing.
*/
contract FinalizableCrowdsale is TimedCrowdsale {
using SafeMath for uint256;
bool private _finalized;
event CrowdsaleFinalized();
constructor () internal {
_finalized = false;
}
/**
* @return true if the crowdsale is finalized, false otherwise.
*/
function finalized() public view returns (bool) {
return _finalized;
}
/**
* @dev Must be called after crowdsale ends, to do some extra finalization
* work. Calls the contract's finalization function.
*/
function finalize() public {
require(!_finalized, "FinalizableCrowdsale: already finalized");
require(hasClosed(), "FinalizableCrowdsale: not closed");
_finalized = true;
_finalization();
emit CrowdsaleFinalized();
}
/**
* @dev Can be overridden to add finalization logic. The overriding function
* should call super._finalization() to ensure the chain of finalization is
* executed entirely.
*/
function _finalization() internal {
// solhint-disable-previous-line no-empty-blocks
}
}
// File: openzeppelin-solidity/contracts/ownership/Secondary.sol
/**
* @dev A Secondary contract can only be used by its primary account (the one that created it).
*/
contract Secondary is Context {
address private _primary;
/**
* @dev Emitted when the primary contract changes.
*/
event PrimaryTransferred(
address recipient
);
/**
* @dev Sets the primary account to the one that is creating the Secondary contract.
*/
constructor () internal {
_primary = _msgSender();
emit PrimaryTransferred(_primary);
}
/**
* @dev Reverts if called from any account other than the primary.
*/
modifier onlyPrimary() {
require(_msgSender() == _primary, "Secondary: caller is not the primary account");
_;
}
/**
* @return the address of the primary.
*/
function primary() public view returns (address) {
return _primary;
}
/**
* @dev Transfers contract to a new primary.
* @param recipient The address of new primary.
*/
function transferPrimary(address recipient) public onlyPrimary {
require(recipient != address(0), "Secondary: new primary is the zero address");
_primary = recipient;
emit PrimaryTransferred(_primary);
}
}
// File: openzeppelin-solidity/contracts/payment/escrow/Escrow.sol
/**
* @title Escrow
* @dev Base escrow contract, holds funds designated for a payee until they
* withdraw them.
*
* Intended usage: This contract (and derived escrow contracts) should be a
* standalone contract, that only interacts with the contract that instantiated
* it. That way, it is guaranteed that all Ether will be handled according to
* the `Escrow` rules, and there is no need to check for payable functions or
* transfers in the inheritance tree. The contract that uses the escrow as its
* payment method should be its primary, and provide public methods redirecting
* to the escrow's deposit and withdraw.
*/
contract Escrow is Secondary {
using SafeMath for uint256;
using Address for address payable;
event Deposited(address indexed payee, uint256 weiAmount);
event Withdrawn(address indexed payee, uint256 weiAmount);
mapping(address => uint256) private _deposits;
function depositsOf(address payee) public view returns (uint256) {
return _deposits[payee];
}
/**
* @dev Stores the sent amount as credit to be withdrawn.
* @param payee The destination address of the funds.
*/
function deposit(address payee) public onlyPrimary payable {
uint256 amount = msg.value;
_deposits[payee] = _deposits[payee].add(amount);
emit Deposited(payee, amount);
}
/**
* @dev Withdraw accumulated balance for a payee, forwarding 2300 gas (a
* Solidity `transfer`).
*
* NOTE: This function has been deprecated, use {withdrawWithGas} instead.
* Calling contracts with fixed-gas limits is an anti-pattern and may break
* contract interactions in network upgrades (hardforks).
* https://diligence.consensys.net/blog/2019/09/stop-using-soliditys-transfer-now/[Learn more.]
*
* @param payee The address whose funds will be withdrawn and transferred to.
*/
function withdraw(address payable payee) public onlyPrimary {
uint256 payment = _deposits[payee];
_deposits[payee] = 0;
payee.transfer(payment);
emit Withdrawn(payee, payment);
}
/**
* @dev Same as {withdraw}, but forwarding all gas to the recipient.
*
* WARNING: Forwarding all gas opens the door to reentrancy vulnerabilities.
* Make sure you trust the recipient, or are either following the
* checks-effects-interactions pattern or using {ReentrancyGuard}.
*
* _Available since v2.4.0._
*/
function withdrawWithGas(address payable payee) public onlyPrimary {
uint256 payment = _deposits[payee];
_deposits[payee] = 0;
payee.sendValue(payment);
emit Withdrawn(payee, payment);
}
}
// File: openzeppelin-solidity/contracts/payment/escrow/ConditionalEscrow.sol
/**
* @title ConditionalEscrow
* @dev Base abstract escrow to only allow withdrawal if a condition is met.
* @dev Intended usage: See {Escrow}. Same usage guidelines apply here.
*/
contract ConditionalEscrow is Escrow {
/**
* @dev Returns whether an address is allowed to withdraw their funds. To be
* implemented by derived contracts.
* @param payee The destination address of the funds.
*/
function withdrawalAllowed(address payee) public view returns (bool);
function withdraw(address payable payee) public {
require(withdrawalAllowed(payee), "ConditionalEscrow: payee is not allowed to withdraw");
super.withdraw(payee);
}
}
// File: openzeppelin-solidity/contracts/payment/escrow/RefundEscrow.sol
/**
* @title RefundEscrow
* @dev Escrow that holds funds for a beneficiary, deposited from multiple
* parties.
* @dev Intended usage: See {Escrow}. Same usage guidelines apply here.
* @dev The primary account (that is, the contract that instantiates this
* contract) may deposit, close the deposit period, and allow for either
* withdrawal by the beneficiary, or refunds to the depositors. All interactions
* with `RefundEscrow` will be made through the primary contract. See the
* `RefundableCrowdsale` contract for an example of `RefundEscrow`’s use.
*/
contract RefundEscrow is ConditionalEscrow {
enum State { Active, Refunding, Closed }
event RefundsClosed();
event RefundsEnabled();
State private _state;
address payable private _beneficiary;
/**
* @dev Constructor.
* @param beneficiary The beneficiary of the deposits.
*/
constructor (address payable beneficiary) public {
require(beneficiary != address(0), "RefundEscrow: beneficiary is the zero address");
_beneficiary = beneficiary;
_state = State.Active;
}
/**
* @return The current state of the escrow.
*/
function state() public view returns (State) {
return _state;
}
/**
* @return The beneficiary of the escrow.
*/
function beneficiary() public view returns (address) {
return _beneficiary;
}
/**
* @dev Stores funds that may later be refunded.
* @param refundee The address funds will be sent to if a refund occurs.
*/
function deposit(address refundee) public payable {
require(_state == State.Active, "RefundEscrow: can only deposit while active");
super.deposit(refundee);
}
/**
* @dev Allows for the beneficiary to withdraw their funds, rejecting
* further deposits.
*/
function close() public onlyPrimary {
require(_state == State.Active, "RefundEscrow: can only close while active");
_state = State.Closed;
emit RefundsClosed();
}
/**
* @dev Allows for refunds to take place, rejecting further deposits.
*/
function enableRefunds() public onlyPrimary {
require(_state == State.Active, "RefundEscrow: can only enable refunds while active");
_state = State.Refunding;
emit RefundsEnabled();
}
/**
* @dev Withdraws the beneficiary's funds.
*/
function beneficiaryWithdraw() public {
require(_state == State.Closed, "RefundEscrow: beneficiary can only withdraw while closed");
_beneficiary.transfer(address(this).balance);
}
/**
* @dev Returns whether refundees can withdraw their deposits (be refunded). The overridden function receives a
* 'payee' argument, but we ignore it here since the condition is global, not per-payee.
*/
function withdrawalAllowed(address) public view returns (bool) {
return _state == State.Refunding;
}
}
// File: openzeppelin-solidity/contracts/crowdsale/distribution/RefundableCrowdsale.sol
/**
* @title RefundableCrowdsale
* @dev Extension of `FinalizableCrowdsale` contract that adds a funding goal, and the possibility of users
* getting a refund if goal is not met.
*
* Deprecated, use `RefundablePostDeliveryCrowdsale` instead. Note that if you allow tokens to be traded before the goal
* is met, then an attack is possible in which the attacker purchases tokens from the crowdsale and when they sees that
* the goal is unlikely to be met, they sell their tokens (possibly at a discount). The attacker will be refunded when
* the crowdsale is finalized, and the users that purchased from them will be left with worthless tokens.
*/
contract RefundableCrowdsale is Context, FinalizableCrowdsale {
using SafeMath for uint256;
// minimum amount of funds to be raised in weis
uint256 private _goal;
// refund escrow used to hold funds while crowdsale is running
RefundEscrow private _escrow;
/**
* @dev Constructor, creates RefundEscrow.
* @param goal Funding goal
*/
constructor (uint256 goal) public {
require(goal > 0, "RefundableCrowdsale: goal is 0");
_escrow = new RefundEscrow(wallet());
_goal = goal;
}
/**
* @return minimum amount of funds to be raised in wei.
*/
function goal() public view returns (uint256) {
return _goal;
}
/**
* @dev Investors can claim refunds here if crowdsale is unsuccessful.
* @param refundee Whose refund will be claimed.
*/
function claimRefund(address payable refundee) public {
require(finalized(), "RefundableCrowdsale: not finalized");
require(!goalReached(), "RefundableCrowdsale: goal reached");
_escrow.withdraw(refundee);
}
/**
* @dev Checks whether funding goal was reached.
* @return Whether funding goal was reached
*/
function goalReached() public view returns (bool) {
return weiRaised() >= _goal;
}
/**
* @dev Escrow finalization task, called when finalize() is called.
*/
function _finalization() internal {
if (goalReached()) {
_escrow.close();
_escrow.beneficiaryWithdraw();
} else {
_escrow.enableRefunds();
}
super._finalization();
}
/**
* @dev Overrides Crowdsale fund forwarding, sending funds to escrow.
*/
function _forwardFunds() internal {
_escrow.deposit.value(msg.value)(_msgSender());
}
}
// File: openzeppelin-solidity/contracts/token/ERC20/ERC20.sol
/**
* @dev Implementation of the {IERC20} interface.
*
* This implementation is agnostic to the way tokens are created. This means
* that a supply mechanism has to be added in a derived contract using {_mint}.
* For a generic mechanism see {ERC20Mintable}.
*
* TIP: For a detailed writeup see our guide
* https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
* to implement supply mechanisms].
*
* We have followed general OpenZeppelin guidelines: functions revert instead
* of returning `false` on failure. This behavior is nonetheless conventional
* and does not conflict with the expectations of ERC20 applications.
*
* Additionally, an {Approval} event is emitted on calls to {transferFrom}.
* This allows applications to reconstruct the allowance for all accounts just
* by listening to said events. Other implementations of the EIP may not emit
* these events, as it isn't required by the specification.
*
* Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
* functions have been added to mitigate the well-known issues around setting
* allowances. See {IERC20-approve}.
*/
contract ERC20 is Context, IERC20 {
using SafeMath for uint256;
mapping (address => uint256) private _balances;
mapping (address => mapping (address => uint256)) private _allowances;
uint256 private _totalSupply;
/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view returns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) public view returns (uint256) {
return _balances[account];
}
/**
* @dev See {IERC20-transfer}.
*
* Requirements:
*
* - `recipient` cannot be the zero address.
* - the caller must have a balance of at least `amount`.
*/
function transfer(address recipient, uint256 amount) public returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
/**
* @dev See {IERC20-allowance}.
*/
function allowance(address owner, address spender) public view returns (uint256) {
return _allowances[owner][spender];
}
/**
* @dev See {IERC20-approve}.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 amount) public returns (bool) {
_approve(_msgSender(), spender, amount);
return true;
}
/**
* @dev See {IERC20-transferFrom}.
*
* Emits an {Approval} event indicating the updated allowance. This is not
* required by the EIP. See the note at the beginning of {ERC20};
*
* Requirements:
* - `sender` and `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
* - the caller must have allowance for `sender`'s tokens of at least
* `amount`.
*/
function transferFrom(address sender, address recipient, uint256 amount) public returns (bool) {
_transfer(sender, recipient, amount);
_approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
return true;
}
/**
* @dev Atomically increases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
return true;
}
/**
* @dev Atomically decreases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `spender` must have allowance for the caller of at least
* `subtractedValue`.
*/
function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
return true;
}
/**
* @dev Moves tokens `amount` from `sender` to `recipient`.
*
* This is internal function is equivalent to {transfer}, and can be used to
* e.g. implement automatic token fees, slashing mechanisms, etc.
*
* Emits a {Transfer} event.
*
* Requirements:
*
* - `sender` cannot be the zero address.
* - `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
*/
function _transfer(address sender, address recipient, uint256 amount) internal {
require(sender != address(0), "ERC20: transfer from the zero address");
require(recipient != address(0), "ERC20: transfer to the zero address");
_balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
_balances[recipient] = _balances[recipient].add(amount);
emit Transfer(sender, recipient, amount);
}
/** @dev Creates `amount` tokens and assigns them to `account`, increasing
* the total supply.
*
* Emits a {Transfer} event with `from` set to the zero address.
*
* Requirements
*
* - `to` cannot be the zero address.
*/
function _mint(address account, uint256 amount) internal {
require(account != address(0), "ERC20: mint to the zero address");
_totalSupply = _totalSupply.add(amount);
_balances[account] = _balances[account].add(amount);
emit Transfer(address(0), account, amount);
}
/**
* @dev Destroys `amount` tokens from `account`, reducing the
* total supply.
*
* Emits a {Transfer} event with `to` set to the zero address.
*
* Requirements
*
* - `account` cannot be the zero address.
* - `account` must have at least `amount` tokens.
*/
function _burn(address account, uint256 amount) internal {
require(account != address(0), "ERC20: burn from the zero address");
_balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
_totalSupply = _totalSupply.sub(amount);
emit Transfer(account, address(0), amount);
}
/**
* @dev Sets `amount` as the allowance of `spender` over the `owner`s tokens.
*
* This is internal function is equivalent to `approve`, and can be used to
* e.g. set automatic allowances for certain subsystems, etc.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `owner` cannot be the zero address.
* - `spender` cannot be the zero address.
*/
function _approve(address owner, address spender, uint256 amount) internal {
require(owner != address(0), "ERC20: approve from the zero address");
require(spender != address(0), "ERC20: approve to the zero address");
_allowances[owner][spender] = amount;
emit Approval(owner, spender, amount);
}
/**
* @dev Destroys `amount` tokens from `account`.`amount` is then deducted
* from the caller's allowance.
*
* See {_burn} and {_approve}.
*/
function _burnFrom(address account, uint256 amount) internal {
_burn(account, amount);
_approve(account, _msgSender(), _allowances[account][_msgSender()].sub(amount, "ERC20: burn amount exceeds allowance"));
}
}
// File: openzeppelin-solidity/contracts/access/Roles.sol
/**
* @title Roles
* @dev Library for managing addresses assigned to a Role.
*/
library Roles {
struct Role {
mapping (address => bool) bearer;
}
/**
* @dev Give an account access to this role.
*/
function add(Role storage role, address account) internal {
require(!has(role, account), "Roles: account already has role");
role.bearer[account] = true;
}
/**
* @dev Remove an account's access to this role.
*/
function remove(Role storage role, address account) internal {
require(has(role, account), "Roles: account does not have role");
role.bearer[account] = false;
}
/**
* @dev Check if an account has this role.
* @return bool
*/
function has(Role storage role, address account) internal view returns (bool) {
require(account != address(0), "Roles: account is the zero address");
return role.bearer[account];
}
}
// File: openzeppelin-solidity/contracts/access/roles/MinterRole.sol
contract MinterRole is Context {
using Roles for Roles.Role;
event MinterAdded(address indexed account);
event MinterRemoved(address indexed account);
Roles.Role private _minters;
constructor () internal {
_addMinter(_msgSender());
}
modifier onlyMinter() {
require(isMinter(_msgSender()), "MinterRole: caller does not have the Minter role");
_;
}
function isMinter(address account) public view returns (bool) {
return _minters.has(account);
}
function addMinter(address account) public onlyMinter {
_addMinter(account);
}
function renounceMinter() public {
_removeMinter(_msgSender());
}
function _addMinter(address account) internal {
_minters.add(account);
emit MinterAdded(account);
}
function _removeMinter(address account) internal {
_minters.remove(account);
emit MinterRemoved(account);
}
}
// File: openzeppelin-solidity/contracts/token/ERC20/ERC20Mintable.sol
/**
* @dev Extension of {ERC20} that adds a set of accounts with the {MinterRole},
* which have permission to mint (create) new tokens as they see fit.
*
* At construction, the deployer of the contract is the only minter.
*/
contract ERC20Mintable is ERC20, MinterRole {
/**
* @dev See {ERC20-_mint}.
*
* Requirements:
*
* - the caller must have the {MinterRole}.
*/
function mint(address account, uint256 amount) public onlyMinter returns (bool) {
_mint(account, amount);
return true;
}
}
// File: openzeppelin-solidity/contracts/crowdsale/emission/MintedCrowdsale.sol
/**
* @title MintedCrowdsale
* @dev Extension of Crowdsale contract whose tokens are minted in each purchase.
* Token ownership should be transferred to MintedCrowdsale for minting.
*/
contract MintedCrowdsale is Crowdsale {
/**
* @dev Overrides delivery by minting tokens upon purchase.
* @param beneficiary Token purchaser
* @param tokenAmount Number of tokens to be minted
*/
function _deliverTokens(address beneficiary, uint256 tokenAmount) internal {
// Potentially dangerous assumption about the type of the token.
require(
ERC20Mintable(address(token())).mint(beneficiary, tokenAmount),
"MintedCrowdsale: minting failed"
);
}
}
// File: openzeppelin-solidity/contracts/token/ERC20/ERC20Detailed.sol
/**
* @dev Optional functions from the ERC20 standard.
*/
contract ERC20Detailed is IERC20 {
string private _name;
string private _symbol;
uint8 private _decimals;
/**
* @dev Sets the values for `name`, `symbol`, and `decimals`. All three of
* these values are immutable: they can only be set once during
* construction.
*/
constructor (string memory name, string memory symbol, uint8 decimals) public {
_name = name;
_symbol = symbol;
_decimals = decimals;
}
/**
* @dev Returns the name of the token.
*/
function name() public view returns (string memory) {
return _name;
}
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() public view returns (string memory) {
return _symbol;
}
/**
* @dev Returns the number of decimals used to get its user representation.
* For example, if `decimals` equals `2`, a balance of `505` tokens should
* be displayed to a user as `5,05` (`505 / 10 ** 2`).
*
* Tokens usually opt for a value of 18, imitating the relationship between
* Ether and Wei.
*
* NOTE: This information is only used for _display_ purposes: it in
* no way affects any of the arithmetic of the contract, including
* {IERC20-balanceOf} and {IERC20-transfer}.
*/
function decimals() public view returns (uint8) {
return _decimals;
}
}
// File: contracts/CovidToken.sol
// solium-disable linebreak-style
pragma solidity >=0.4.21 <0.7.0;
/**
* @title SampleCrowdsaleToken
* @dev Very simple ERC20 Token that can be minted.
* It is meant to be used in a crowdsale contract.
*/
contract ulluToken is ERC20Mintable, ERC20Detailed {
constructor( string memory _name, string memory _symbol, uint8 _decimals)
ERC20Detailed(_name, _symbol, _decimals)
public
{
}
}
/**
* @title SampleCrowdsale
* @dev This is an example of a fully fledged crowdsale.
* The way to add new features to a base crowdsale is by multiple inheritance.
* In this example we are providing following extensions:
* CappedCrowdsale - sets a max boundary for raised funds
* RefundableCrowdsale - set a min goal to be reached and returns funds if it's not met
* MintedCrowdsale - assumes the token can be minted by the crowdsale, which does so
* when receiving purchases.
*
* After adding multiple features it's good practice to run integration tests
* to ensure that subcontracts works together as intended.
*/