0926729c8f
* Add StandardBurnableToken implementation BurnableToken that extends from StandardToken and adds a burnFrom method that decrements allowance. Equivalent to a transferFrom plus burn in a single operation. * Return event object from expectEvent helper * Add comment on Approval event in burnFrom function * Improvements on burnable token tests - Inject initial balance as a parameter to the behaviour - Use expectEvent helper for assertions on events - Use chai bignumber for numbers - Change to bdd-style assertions
25 lines
862 B
Solidity
25 lines
862 B
Solidity
pragma solidity ^0.4.18;
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import "./BurnableToken.sol";
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import "./StandardToken.sol";
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/**
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* @title Standard Burnable Token
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* @dev Adds burnFrom method to ERC20 implementations
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*/
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contract StandardBurnableToken is BurnableToken, StandardToken {
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/**
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* @dev Burns a specific amount of tokens from the target address and decrements allowance
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* @param _from address The address which you want to send tokens from
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* @param _value uint256 The amount of token to be burned
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*/
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function burnFrom(address _from, uint256 _value) public {
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require(_value <= allowed[_from][msg.sender]);
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// Should https://github.com/OpenZeppelin/zeppelin-solidity/issues/707 be accepted,
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// this function needs to emit an event with the updated approval.
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allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
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_burn(_from, _value);
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}
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}
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