60 lines
1.5 KiB
Solidity
60 lines
1.5 KiB
Solidity
pragma solidity ^0.4.24;
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import "../Crowdsale.sol";
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import "../../token/ERC20/IERC20.sol";
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import "../../token/ERC20/SafeERC20.sol";
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import "../../math/SafeMath.sol";
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import "../../math/Math.sol";
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/**
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* @title AllowanceCrowdsale
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* @dev Extension of Crowdsale where tokens are held by a wallet, which approves an allowance to the crowdsale.
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*/
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contract AllowanceCrowdsale is Crowdsale {
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using SafeMath for uint256;
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using SafeERC20 for IERC20;
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address private _tokenWallet;
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/**
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* @dev Constructor, takes token wallet address.
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* @param tokenWallet Address holding the tokens, which has approved allowance to the crowdsale
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*/
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constructor(address tokenWallet) internal {
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require(tokenWallet != address(0));
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_tokenWallet = tokenWallet;
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}
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/**
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* @return the address of the wallet that will hold the tokens.
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*/
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function tokenWallet() public view returns(address) {
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return _tokenWallet;
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}
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/**
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* @dev Checks the amount of tokens left in the allowance.
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* @return Amount of tokens left in the allowance
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*/
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function remainingTokens() public view returns (uint256) {
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return Math.min(
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token().balanceOf(_tokenWallet),
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token().allowance(_tokenWallet, this)
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);
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}
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/**
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* @dev Overrides parent behavior by transferring tokens from wallet.
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* @param beneficiary Token purchaser
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* @param tokenAmount Amount of tokens purchased
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*/
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function _deliverTokens(
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address beneficiary,
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uint256 tokenAmount
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)
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internal
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{
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token().safeTransferFrom(_tokenWallet, beneficiary, tokenAmount);
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}
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}
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