[TokenVesting] Remove VestedToken and LimitedTranferToken
This commit is contained in:
Martín Triay
@ -1,57 +0,0 @@
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pragma solidity ^0.4.11;
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import "./ERC20.sol";
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/**
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* @title LimitedTransferToken
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* @dev LimitedTransferToken defines the generic interface and the implementation to limit token
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* transferability for different events. It is intended to be used as a base class for other token
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* contracts.
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* LimitedTransferToken has been designed to allow for different limiting factors,
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* this can be achieved by recursively calling super.transferableTokens() until the base class is
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* hit. For example:
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* function transferableTokens(address holder, uint64 time) constant public returns (uint256) {
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* return min256(unlockedTokens, super.transferableTokens(holder, time));
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* }
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* A working example is VestedToken.sol:
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* https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/contracts/token/VestedToken.sol
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*/
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contract LimitedTransferToken is ERC20 {
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/**
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* @dev Checks whether it can transfer or otherwise throws.
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*/
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modifier canTransfer(address _sender, uint256 _value) {
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require(_value <= transferableTokens(_sender, uint64(now)));
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_;
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}
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/**
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* @dev Checks modifier and allows transfer if tokens are not locked.
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* @param _to The address that will receive the tokens.
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* @param _value The amount of tokens to be transferred.
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*/
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function transfer(address _to, uint256 _value) canTransfer(msg.sender, _value) public returns (bool) {
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return super.transfer(_to, _value);
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}
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/**
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* @dev Checks modifier and allows transfer if tokens are not locked.
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* @param _from The address that will send the tokens.
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* @param _to The address that will receive the tokens.
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* @param _value The amount of tokens to be transferred.
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*/
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function transferFrom(address _from, address _to, uint256 _value) canTransfer(_from, _value) public returns (bool) {
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return super.transferFrom(_from, _to, _value);
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}
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/**
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* @dev Default transferable tokens function returns all tokens for a holder (no limit).
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* @dev Overwriting transferableTokens(address holder, uint64 time) is the way to provide the
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* specific logic for limiting token transferability for a holder over time.
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*/
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function transferableTokens(address holder, uint64 time) public constant returns (uint256) {
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return balanceOf(holder);
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}
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}
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@ -1,241 +0,0 @@
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pragma solidity ^0.4.11;
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import "../math/Math.sol";
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import "./StandardToken.sol";
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import "./LimitedTransferToken.sol";
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/**
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* @title Vested token
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* @dev Tokens that can be vested for a group of addresses.
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*/
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contract VestedToken is StandardToken, LimitedTransferToken {
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uint256 MAX_GRANTS_PER_ADDRESS = 20;
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struct TokenGrant {
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address granter; // 20 bytes
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uint256 value; // 32 bytes
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uint64 cliff;
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uint64 vesting;
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uint64 start; // 3 * 8 = 24 bytes
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bool revokable;
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bool burnsOnRevoke; // 2 * 1 = 2 bits? or 2 bytes?
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} // total 78 bytes = 3 sstore per operation (32 per sstore)
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mapping (address => TokenGrant[]) public grants;
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event NewTokenGrant(address indexed from, address indexed to, uint256 value, uint256 grantId);
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/**
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* @dev Grant tokens to a specified address
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* @param _to address The address which the tokens will be granted to.
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* @param _value uint256 The amount of tokens to be granted.
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* @param _start uint64 Time of the beginning of the grant.
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* @param _cliff uint64 Time of the cliff period.
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* @param _vesting uint64 The vesting period.
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*/
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function grantVestedTokens(
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address _to,
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uint256 _value,
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uint64 _start,
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uint64 _cliff,
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uint64 _vesting,
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bool _revokable,
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bool _burnsOnRevoke
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) public {
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// Check for date inconsistencies that may cause unexpected behavior
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require(_cliff >= _start && _vesting >= _cliff);
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require(tokenGrantsCount(_to) < MAX_GRANTS_PER_ADDRESS); // To prevent a user being spammed and have his balance locked (out of gas attack when calculating vesting).
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uint256 count = grants[_to].push(
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TokenGrant(
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_revokable ? msg.sender : 0, // avoid storing an extra 20 bytes when it is non-revokable
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_value,
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_cliff,
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_vesting,
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_start,
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_revokable,
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_burnsOnRevoke
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)
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);
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transfer(_to, _value);
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NewTokenGrant(msg.sender, _to, _value, count - 1);
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}
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/**
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* @dev Revoke the grant of tokens of a specifed address.
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* @param _holder The address which will have its tokens revoked.
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* @param _grantId The id of the token grant.
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*/
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function revokeTokenGrant(address _holder, uint256 _grantId) public {
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TokenGrant storage grant = grants[_holder][_grantId];
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require(grant.revokable);
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require(grant.granter == msg.sender); // Only granter can revoke it
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address receiver = grant.burnsOnRevoke ? 0xdead : msg.sender;
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uint256 nonVested = nonVestedTokens(grant, uint64(now));
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// remove grant from array
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delete grants[_holder][_grantId];
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grants[_holder][_grantId] = grants[_holder][grants[_holder].length.sub(1)];
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grants[_holder].length -= 1;
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balances[receiver] = balances[receiver].add(nonVested);
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balances[_holder] = balances[_holder].sub(nonVested);
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Transfer(_holder, receiver, nonVested);
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}
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/**
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* @dev Calculate the total amount of transferable tokens of a holder at a given time
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* @param holder address The address of the holder
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* @param time uint64 The specific time.
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* @return An uint256 representing a holder's total amount of transferable tokens.
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*/
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function transferableTokens(address holder, uint64 time) public constant returns (uint256) {
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uint256 grantIndex = tokenGrantsCount(holder);
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if (grantIndex == 0) return super.transferableTokens(holder, time); // shortcut for holder without grants
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// Iterate through all the grants the holder has, and add all non-vested tokens
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uint256 nonVested = 0;
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for (uint256 i = 0; i < grantIndex; i++) {
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nonVested = SafeMath.add(nonVested, nonVestedTokens(grants[holder][i], time));
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}
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// Balance - totalNonVested is the amount of tokens a holder can transfer at any given time
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uint256 vestedTransferable = SafeMath.sub(balanceOf(holder), nonVested);
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// Return the minimum of how many vested can transfer and other value
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// in case there are other limiting transferability factors (default is balanceOf)
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return Math.min256(vestedTransferable, super.transferableTokens(holder, time));
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}
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/**
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* @dev Check the amount of grants that an address has.
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* @param _holder The holder of the grants.
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* @return A uint256 representing the total amount of grants.
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*/
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function tokenGrantsCount(address _holder) public constant returns (uint256 index) {
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return grants[_holder].length;
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}
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/**
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* @dev Calculate amount of vested tokens at a specific time
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* @param tokens uint256 The amount of tokens granted
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* @param time uint64 The time to be checked
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* @param start uint64 The time representing the beginning of the grant
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* @param cliff uint64 The cliff period, the period before nothing can be paid out
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* @param vesting uint64 The vesting period
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* @return An uint256 representing the amount of vested tokens of a specific grant
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* transferableTokens
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* | _/-------- vestedTokens rect
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* | _/
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* | _/
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* | _/
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* | _/
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* | /
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* | .|
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* | . |
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* | . |
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* | . |
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* | . |
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* | . |
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* +===+===========+---------+----------> time
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* Start Cliff Vesting
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*/
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function calculateVestedTokens(
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uint256 tokens,
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uint256 time,
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uint256 start,
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uint256 cliff,
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uint256 vesting) public constant returns (uint256)
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{
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// Shortcuts for before cliff and after vesting cases.
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if (time < cliff) return 0;
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if (time >= vesting) return tokens;
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// Interpolate all vested tokens.
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// As before cliff the shortcut returns 0, we can use just calculate a value
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// in the vesting rect (as shown in above's figure)
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// vestedTokens = (tokens * (time - start)) / (vesting - start)
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uint256 vestedTokens = SafeMath.div(
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SafeMath.mul(
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tokens,
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SafeMath.sub(time, start)
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),
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SafeMath.sub(vesting, start)
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);
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return vestedTokens;
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}
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/**
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* @dev Get all information about a specific grant.
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* @param _holder The address which will have its tokens revoked.
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* @param _grantId The id of the token grant.
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* @return Returns all the values that represent a TokenGrant(address, value, start, cliff,
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* revokability, burnsOnRevoke, and vesting) plus the vested value at the current time.
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*/
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function tokenGrant(address _holder, uint256 _grantId) public constant returns (address granter, uint256 value, uint256 vested, uint64 start, uint64 cliff, uint64 vesting, bool revokable, bool burnsOnRevoke) {
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TokenGrant storage grant = grants[_holder][_grantId];
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granter = grant.granter;
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value = grant.value;
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start = grant.start;
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cliff = grant.cliff;
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vesting = grant.vesting;
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revokable = grant.revokable;
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burnsOnRevoke = grant.burnsOnRevoke;
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vested = vestedTokens(grant, uint64(now));
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}
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/**
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* @dev Get the amount of vested tokens at a specific time.
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* @param grant TokenGrant The grant to be checked.
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* @param time The time to be checked
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* @return An uint256 representing the amount of vested tokens of a specific grant at a specific time.
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*/
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function vestedTokens(TokenGrant grant, uint64 time) private constant returns (uint256) {
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return calculateVestedTokens(
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grant.value,
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uint256(time),
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uint256(grant.start),
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uint256(grant.cliff),
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uint256(grant.vesting)
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);
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}
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/**
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* @dev Calculate the amount of non vested tokens at a specific time.
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* @param grant TokenGrant The grant to be checked.
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* @param time uint64 The time to be checked
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* @return An uint256 representing the amount of non vested tokens of a specific grant on the
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* passed time frame.
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*/
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function nonVestedTokens(TokenGrant grant, uint64 time) private constant returns (uint256) {
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return grant.value.sub(vestedTokens(grant, time));
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}
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/**
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* @dev Calculate the date when the holder can transfer all its tokens
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* @param holder address The address of the holder
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* @return An uint256 representing the date of the last transferable tokens.
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*/
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function lastTokenIsTransferableDate(address holder) public constant returns (uint64 date) {
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date = uint64(now);
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uint256 grantIndex = grants[holder].length;
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for (uint256 i = 0; i < grantIndex; i++) {
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date = Math.max64(grants[holder][i].vesting, date);
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}
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}
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}
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@ -1,175 +0,0 @@
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const assertJump = require('./helpers/assertJump');
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const timer = require('./helpers/timer');
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var VestedTokenMock = artifacts.require("./helpers/VestedTokenMock.sol");
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contract('VestedToken', function(accounts) {
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let token = null
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let now = 0
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const tokenAmount = 50
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const granter = accounts[0]
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const receiver = accounts[1]
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beforeEach(async () => {
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token = await VestedTokenMock.new(granter, 100);
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now = web3.eth.getBlock(web3.eth.blockNumber).timestamp;
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})
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it('granter can grant tokens without vesting', async () => {
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await token.transfer(receiver, tokenAmount, { from: granter })
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assert.equal(await token.balanceOf(receiver), tokenAmount);
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assert.equal(await token.transferableTokens(receiver, now), tokenAmount);
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})
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describe('getting a revokable/non-burnable token grant', async () => {
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const cliff = 10000
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const vesting = 20000 // seconds
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beforeEach(async () => {
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await token.grantVestedTokens(receiver, tokenAmount, now, now + cliff, now + vesting, true, false, { from: granter })
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})
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it('tokens are received', async () => {
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assert.equal(await token.balanceOf(receiver), tokenAmount);
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})
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it('has 0 transferable tokens before cliff', async () => {
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assert.equal(await token.transferableTokens(receiver, now), 0);
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})
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it('all tokens are transferable after vesting', async () => {
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assert.equal(await token.transferableTokens(receiver, now + vesting), tokenAmount);
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})
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it('throws when trying to transfer non vested tokens', async () => {
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try {
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await token.transfer(accounts[7], 1, { from: receiver })
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assert.fail('should have thrown before');
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} catch(error) {
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assertJump(error);
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}
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})
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it('throws when trying to transfer from non vested tokens', async () => {
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try {
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await token.approve(accounts[7], 1, { from: receiver })
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await token.transferFrom(receiver, accounts[7], tokenAmount, { from: accounts[7] })
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assert.fail('should have thrown before');
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} catch(error) {
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assertJump(error);
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}
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})
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it('can be revoked by granter', async () => {
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await token.revokeTokenGrant(receiver, 0, { from: granter });
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assert.equal(await token.balanceOf(receiver), 0);
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assert.equal(await token.balanceOf(granter), 100);
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})
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it('cannot be revoked by non granter', async () => {
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try {
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await token.revokeTokenGrant(receiver, 0, { from: accounts[3] });
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assert.fail('should have thrown before');
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} catch(error) {
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assertJump(error);
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}
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})
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it('can be revoked by granter and non vested tokens are returned', async () => {
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await timer(cliff);
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await token.revokeTokenGrant(receiver, 0, { from: granter });
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assert.equal(await token.balanceOf(receiver), tokenAmount * cliff / vesting);
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})
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it('can transfer all tokens after vesting ends', async () => {
|
|
||||||
await timer(vesting);
|
|
||||||
await token.transfer(accounts[7], tokenAmount, { from: receiver })
|
|
||||||
assert.equal(await token.balanceOf(accounts[7]), tokenAmount);
|
|
||||||
})
|
|
||||||
|
|
||||||
it('can approve and transferFrom all tokens after vesting ends', async () => {
|
|
||||||
await timer(vesting);
|
|
||||||
await token.approve(accounts[7], tokenAmount, { from: receiver })
|
|
||||||
await token.transferFrom(receiver, accounts[7], tokenAmount, { from: accounts[7] })
|
|
||||||
assert.equal(await token.balanceOf(accounts[7]), tokenAmount);
|
|
||||||
})
|
|
||||||
|
|
||||||
it('can handle composed vesting schedules', async () => {
|
|
||||||
await timer(cliff);
|
|
||||||
await token.transfer(accounts[7], 12, { from: receiver })
|
|
||||||
assert.equal(await token.balanceOf(accounts[7]), 12);
|
|
||||||
|
|
||||||
let newNow = web3.eth.getBlock(web3.eth.blockNumber).timestamp
|
|
||||||
|
|
||||||
await token.grantVestedTokens(receiver, tokenAmount, newNow, newNow + cliff, newNow + vesting, false, false, { from: granter })
|
|
||||||
|
|
||||||
await token.transfer(accounts[7], 13, { from: receiver })
|
|
||||||
assert.equal(await token.balanceOf(accounts[7]), tokenAmount / 2);
|
|
||||||
|
|
||||||
assert.equal(await token.balanceOf(receiver), 3 * tokenAmount / 2)
|
|
||||||
assert.equal(await token.transferableTokens(receiver, newNow), 0)
|
|
||||||
await timer(vesting);
|
|
||||||
await token.transfer(accounts[7], 3 * tokenAmount / 2, { from: receiver })
|
|
||||||
assert.equal(await token.balanceOf(accounts[7]), tokenAmount * 2)
|
|
||||||
})
|
|
||||||
})
|
|
||||||
|
|
||||||
describe('getting a non-revokable token grant', async () => {
|
|
||||||
const cliff = 10000
|
|
||||||
const vesting = 20000 // seconds
|
|
||||||
|
|
||||||
beforeEach(async () => {
|
|
||||||
await token.grantVestedTokens(receiver, tokenAmount, now, now + cliff, now + vesting, false, false, { from: granter })
|
|
||||||
})
|
|
||||||
|
|
||||||
it('tokens are received', async () => {
|
|
||||||
assert.equal(await token.balanceOf(receiver), tokenAmount);
|
|
||||||
})
|
|
||||||
|
|
||||||
it('throws when granter attempts to revoke', async () => {
|
|
||||||
try {
|
|
||||||
await token.revokeTokenGrant(receiver, 0, { from: granter });
|
|
||||||
assert.fail('should have thrown before');
|
|
||||||
} catch(error) {
|
|
||||||
assertJump(error);
|
|
||||||
}
|
|
||||||
})
|
|
||||||
})
|
|
||||||
|
|
||||||
describe('getting a revokable/burnable token grant', async () => {
|
|
||||||
const cliff = 100000
|
|
||||||
const vesting = 200000 // seconds
|
|
||||||
const burnAddress = '0x000000000000000000000000000000000000dead'
|
|
||||||
|
|
||||||
beforeEach(async () => {
|
|
||||||
await token.grantVestedTokens(receiver, tokenAmount, now, now + cliff, now + vesting, true, true, { from: granter })
|
|
||||||
})
|
|
||||||
|
|
||||||
it('tokens are received', async () => {
|
|
||||||
assert.equal(await token.balanceOf(receiver), tokenAmount);
|
|
||||||
})
|
|
||||||
|
|
||||||
it('can be revoked by granter and tokens are burned', async () => {
|
|
||||||
await token.revokeTokenGrant(receiver, 0, { from: granter });
|
|
||||||
assert.equal(await token.balanceOf(receiver), 0);
|
|
||||||
assert.equal(await token.balanceOf(burnAddress), tokenAmount);
|
|
||||||
})
|
|
||||||
|
|
||||||
it('cannot be revoked by non granter', async () => {
|
|
||||||
try {
|
|
||||||
await token.revokeTokenGrant(receiver, 0, { from: accounts[3] });
|
|
||||||
assert.fail('should have thrown before');
|
|
||||||
} catch(error) {
|
|
||||||
assertJump(error);
|
|
||||||
}
|
|
||||||
})
|
|
||||||
|
|
||||||
it('can be revoked by granter and non vested tokens are returned', async () => {
|
|
||||||
await timer(cliff);
|
|
||||||
await token.revokeTokenGrant(receiver, 0, { from: granter });
|
|
||||||
assert.equal(await token.balanceOf(burnAddress), tokenAmount * cliff / vesting);
|
|
||||||
})
|
|
||||||
})
|
|
||||||
});
|
|
||||||
Reference in New Issue
Block a user