638 lines
22 KiB
Solidity
638 lines
22 KiB
Solidity
pragma solidity ^0.4.23;
|
|
|
|
/*
|
|
Copyright 2016, Jordi Baylina
|
|
|
|
This program is free software: you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation, either version 3 of the License, or
|
|
(at your option) any later version.
|
|
|
|
This program is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
/**
|
|
* @title MiniMeToken Contract
|
|
* @author Jordi Baylina
|
|
* @dev This token contract's goal is to make it easy for anyone to clone this
|
|
* token using the token distribution at a given block, this will allow DAO's
|
|
* and DApps to upgrade their features in a decentralized manner without
|
|
* affecting the original token
|
|
* @dev It is ERC20 compliant, but still needs to under go further testing.
|
|
*/
|
|
|
|
import "../common/Controlled.sol";
|
|
import "./TokenController.sol";
|
|
import "./ApproveAndCallFallBack.sol";
|
|
import "./MiniMeTokenInterface.sol";
|
|
import "./MiniMeTokenFactory.sol";
|
|
|
|
/**
|
|
* @dev The actual token contract, the default controller is the msg.sender
|
|
* that deploys the contract, so usually this token will be deployed by a
|
|
* token controller contract, which Giveth will call a "Campaign"
|
|
*/
|
|
contract MiniMeToken is MiniMeTokenInterface, Controlled {
|
|
|
|
string public name; //The Token's name: e.g. DigixDAO Tokens
|
|
uint8 public decimals; //Number of decimals of the smallest unit
|
|
string public symbol; //An identifier: e.g. REP
|
|
string public version = "MMT_0.1"; //An arbitrary versioning scheme
|
|
|
|
/**
|
|
* @dev `Checkpoint` is the structure that attaches a block number to a
|
|
* given value, the block number attached is the one that last changed the
|
|
* value
|
|
*/
|
|
struct Checkpoint {
|
|
|
|
// `fromBlock` is the block number that the value was generated from
|
|
uint128 fromBlock;
|
|
|
|
// `value` is the amount of tokens at a specific block number
|
|
uint128 value;
|
|
}
|
|
|
|
// `parentToken` is the Token address that was cloned to produce this token;
|
|
// it will be 0x0 for a token that was not cloned
|
|
MiniMeToken public parentToken;
|
|
|
|
// `parentSnapShotBlock` is the block number from the Parent Token that was
|
|
// used to determine the initial distribution of the Clone Token
|
|
uint public parentSnapShotBlock;
|
|
|
|
// `creationBlock` is the block number that the Clone Token was created
|
|
uint public creationBlock;
|
|
|
|
// `balances` is the map that tracks the balance of each address, in this
|
|
// contract when the balance changes the block number that the change
|
|
// occurred is also included in the map
|
|
mapping (address => Checkpoint[]) balances;
|
|
|
|
// `allowed` tracks any extra transfer rights as in all ERC20 tokens
|
|
mapping (address => mapping (address => uint256)) allowed;
|
|
|
|
// Tracks the history of the `totalSupply` of the token
|
|
Checkpoint[] totalSupplyHistory;
|
|
|
|
// Flag that determines if the token is transferable or not.
|
|
bool public transfersEnabled;
|
|
|
|
// The factory used to create new clone tokens
|
|
MiniMeTokenFactory public tokenFactory;
|
|
|
|
////////////////
|
|
// Constructor
|
|
////////////////
|
|
|
|
/**
|
|
* @notice Constructor to create a MiniMeToken
|
|
* @param _tokenFactory The address of the MiniMeTokenFactory contract that
|
|
* will create the Clone token contracts, the token factory needs to be
|
|
* deployed first
|
|
* @param _parentToken Address of the parent token, set to 0x0 if it is a
|
|
* new token
|
|
* @param _parentSnapShotBlock Block of the parent token that will
|
|
* determine the initial distribution of the clone token, set to 0 if it
|
|
* is a new token
|
|
* @param _tokenName Name of the new token
|
|
* @param _decimalUnits Number of decimals of the new token
|
|
* @param _tokenSymbol Token Symbol for the new token
|
|
* @param _transfersEnabled If true, tokens will be able to be transferred
|
|
*/
|
|
constructor(
|
|
address _tokenFactory,
|
|
address _parentToken,
|
|
uint _parentSnapShotBlock,
|
|
string _tokenName,
|
|
uint8 _decimalUnits,
|
|
string _tokenSymbol,
|
|
bool _transfersEnabled
|
|
)
|
|
public
|
|
{
|
|
tokenFactory = MiniMeTokenFactory(_tokenFactory);
|
|
name = _tokenName; // Set the name
|
|
decimals = _decimalUnits; // Set the decimals
|
|
symbol = _tokenSymbol; // Set the symbol
|
|
parentToken = MiniMeToken(_parentToken);
|
|
parentSnapShotBlock = _parentSnapShotBlock;
|
|
transfersEnabled = _transfersEnabled;
|
|
creationBlock = block.number;
|
|
}
|
|
|
|
|
|
///////////////////
|
|
// ERC20 Methods
|
|
///////////////////
|
|
|
|
/**
|
|
* @notice Send `_amount` tokens to `_to` from `msg.sender`
|
|
* @param _to The address of the recipient
|
|
* @param _amount The amount of tokens to be transferred
|
|
* @return Whether the transfer was successful or not
|
|
*/
|
|
function transfer(address _to, uint256 _amount) public returns (bool success) {
|
|
require(transfersEnabled);
|
|
return doTransfer(msg.sender, _to, _amount);
|
|
}
|
|
|
|
/**
|
|
* @notice Send `_amount` tokens to `_to` from `_from` on the condition it
|
|
* is approved by `_from`
|
|
* @param _from The address holding the tokens being transferred
|
|
* @param _to The address of the recipient
|
|
* @param _amount The amount of tokens to be transferred
|
|
* @return True if the transfer was successful
|
|
*/
|
|
function transferFrom(
|
|
address _from,
|
|
address _to,
|
|
uint256 _amount
|
|
)
|
|
public
|
|
returns (bool success)
|
|
{
|
|
|
|
// The controller of this contract can move tokens around at will,
|
|
// this is important to recognize! Confirm that you trust the
|
|
// controller of this contract, which in most situations should be
|
|
// another open source smart contract or 0x0
|
|
if (msg.sender != controller) {
|
|
require(transfersEnabled);
|
|
|
|
// The standard ERC 20 transferFrom functionality
|
|
if (allowed[_from][msg.sender] < _amount) {
|
|
return false;
|
|
}
|
|
allowed[_from][msg.sender] -= _amount;
|
|
}
|
|
return doTransfer(_from, _to, _amount);
|
|
}
|
|
|
|
/**
|
|
* @dev This is the actual transfer function in the token contract, it can
|
|
* only be called by other functions in this contract.
|
|
* @param _from The address holding the tokens being transferred
|
|
* @param _to The address of the recipient
|
|
* @param _amount The amount of tokens to be transferred
|
|
* @return True if the transfer was successful
|
|
*/
|
|
function doTransfer(
|
|
address _from,
|
|
address _to,
|
|
uint _amount
|
|
)
|
|
internal
|
|
returns(bool)
|
|
{
|
|
|
|
if (_amount == 0) {
|
|
return true;
|
|
}
|
|
|
|
require(parentSnapShotBlock < block.number);
|
|
|
|
// Do not allow transfer to 0x0 or the token contract itself
|
|
require((_to != 0) && (_to != address(this)));
|
|
|
|
// If the amount being transfered is more than the balance of the
|
|
// account the transfer returns false
|
|
uint256 previousBalanceFrom = balanceOfAt(_from, block.number);
|
|
if (previousBalanceFrom < _amount) {
|
|
return false;
|
|
}
|
|
|
|
// Alerts the token controller of the transfer
|
|
if (isContract(controller)) {
|
|
require(TokenController(controller).onTransfer(_from, _to, _amount));
|
|
}
|
|
|
|
// First update the balance array with the new value for the address
|
|
// sending the tokens
|
|
updateValueAtNow(balances[_from], previousBalanceFrom - _amount);
|
|
|
|
// Then update the balance array with the new value for the address
|
|
// receiving the tokens
|
|
uint256 previousBalanceTo = balanceOfAt(_to, block.number);
|
|
require(previousBalanceTo + _amount >= previousBalanceTo); // Check for overflow
|
|
updateValueAtNow(balances[_to], previousBalanceTo + _amount);
|
|
|
|
// An event to make the transfer easy to find on the blockchain
|
|
emit Transfer(_from, _to, _amount);
|
|
|
|
return true;
|
|
}
|
|
|
|
function doApprove(
|
|
address _from,
|
|
address _spender,
|
|
uint256 _amount
|
|
)
|
|
internal
|
|
returns (bool)
|
|
{
|
|
require(transfersEnabled);
|
|
|
|
// To change the approve amount you first have to reduce the addresses`
|
|
// allowance to zero by calling `approve(_spender,0)` if it is not
|
|
// already 0 to mitigate the race condition described here:
|
|
// https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
|
|
require((_amount == 0) || (allowed[_from][_spender] == 0));
|
|
|
|
// Alerts the token controller of the approve function call
|
|
if (isContract(controller)) {
|
|
require(TokenController(controller).onApprove(_from, _spender, _amount));
|
|
}
|
|
|
|
allowed[_from][_spender] = _amount;
|
|
emit Approval(_from, _spender, _amount);
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* @param _owner The address that's balance is being requested
|
|
* @return The balance of `_owner` at the current block
|
|
*/
|
|
function balanceOf(address _owner) external view returns (uint256 balance) {
|
|
return balanceOfAt(_owner, block.number);
|
|
}
|
|
|
|
/**
|
|
* @notice `msg.sender` approves `_spender` to spend `_amount` tokens on
|
|
* its behalf. This is a modified version of the ERC20 approve function
|
|
* to be a little bit safer
|
|
* @param _spender The address of the account able to transfer the tokens
|
|
* @param _amount The amount of tokens to be approved for transfer
|
|
* @return True if the approval was successful
|
|
*/
|
|
function approve(address _spender, uint256 _amount) external returns (bool success) {
|
|
doApprove(msg.sender, _spender, _amount);
|
|
}
|
|
|
|
/**
|
|
* @dev This function makes it easy to read the `allowed[]` map
|
|
* @param _owner The address of the account that owns the token
|
|
* @param _spender The address of the account able to transfer the tokens
|
|
* @return Amount of remaining tokens of _owner that _spender is allowed
|
|
* to spend
|
|
*/
|
|
function allowance(
|
|
address _owner,
|
|
address _spender
|
|
)
|
|
external
|
|
view
|
|
returns (uint256 remaining)
|
|
{
|
|
return allowed[_owner][_spender];
|
|
}
|
|
/**
|
|
* @notice `msg.sender` approves `_spender` to send `_amount` tokens on
|
|
* its behalf, and then a function is triggered in the contract that is
|
|
* being approved, `_spender`. This allows users to use their tokens to
|
|
* interact with contracts in one function call instead of two
|
|
* @param _spender The address of the contract able to transfer the tokens
|
|
* @param _amount The amount of tokens to be approved for transfer
|
|
* @return True if the function call was successful
|
|
*/
|
|
function approveAndCall(
|
|
address _spender,
|
|
uint256 _amount,
|
|
bytes _extraData
|
|
)
|
|
public
|
|
returns (bool success)
|
|
{
|
|
require(doApprove(msg.sender, _spender, _amount));
|
|
|
|
ApproveAndCallFallBack(_spender).receiveApproval(
|
|
msg.sender,
|
|
_amount,
|
|
this,
|
|
_extraData
|
|
);
|
|
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* @dev This function makes it easy to get the total number of tokens
|
|
* @return The total number of tokens
|
|
*/
|
|
function totalSupply() external view returns (uint) {
|
|
return totalSupplyAt(block.number);
|
|
}
|
|
|
|
|
|
////////////////
|
|
// Query balance and totalSupply in History
|
|
////////////////
|
|
|
|
/**
|
|
* @dev Queries the balance of `_owner` at a specific `_blockNumber`
|
|
* @param _owner The address from which the balance will be retrieved
|
|
* @param _blockNumber The block number when the balance is queried
|
|
* @return The balance at `_blockNumber`
|
|
*/
|
|
function balanceOfAt(
|
|
address _owner,
|
|
uint _blockNumber
|
|
)
|
|
public
|
|
view
|
|
returns (uint)
|
|
{
|
|
|
|
// These next few lines are used when the balance of the token is
|
|
// requested before a check point was ever created for this token, it
|
|
// requires that the `parentToken.balanceOfAt` be queried at the
|
|
// genesis block for that token as this contains initial balance of
|
|
// this token
|
|
if ((balances[_owner].length == 0)
|
|
|| (balances[_owner][0].fromBlock > _blockNumber)) {
|
|
if (address(parentToken) != 0) {
|
|
return parentToken.balanceOfAt(_owner, min(_blockNumber, parentSnapShotBlock));
|
|
} else {
|
|
// Has no parent
|
|
return 0;
|
|
}
|
|
|
|
// This will return the expected balance during normal situations
|
|
} else {
|
|
return getValueAt(balances[_owner], _blockNumber);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @notice Total amount of tokens at a specific `_blockNumber`.
|
|
* @param _blockNumber The block number when the totalSupply is queried
|
|
* @return The total amount of tokens at `_blockNumber`
|
|
*/
|
|
function totalSupplyAt(uint _blockNumber) public view returns(uint) {
|
|
|
|
// These next few lines are used when the totalSupply of the token is
|
|
// requested before a check point was ever created for this token, it
|
|
// requires that the `parentToken.totalSupplyAt` be queried at the
|
|
// genesis block for this token as that contains totalSupply of this
|
|
// token at this block number.
|
|
if ((totalSupplyHistory.length == 0)
|
|
|| (totalSupplyHistory[0].fromBlock > _blockNumber)) {
|
|
if (address(parentToken) != 0) {
|
|
return parentToken.totalSupplyAt(min(_blockNumber, parentSnapShotBlock));
|
|
} else {
|
|
return 0;
|
|
}
|
|
|
|
// This will return the expected totalSupply during normal situations
|
|
} else {
|
|
return getValueAt(totalSupplyHistory, _blockNumber);
|
|
}
|
|
}
|
|
|
|
////////////////
|
|
// Clone Token Method
|
|
////////////////
|
|
|
|
/**
|
|
* @notice Creates a new clone token with the initial distribution being
|
|
* this token at `snapshotBlock`
|
|
* @param _cloneTokenName Name of the clone token
|
|
* @param _cloneDecimalUnits Number of decimals of the smallest unit
|
|
* @param _cloneTokenSymbol Symbol of the clone token
|
|
* @param _snapshotBlock Block when the distribution of the parent token is
|
|
* copied to set the initial distribution of the new clone token;
|
|
* if the block is zero than the actual block, the current block is used
|
|
* @param _transfersEnabled True if transfers are allowed in the clone
|
|
* @return The address of the new MiniMeToken Contract
|
|
*/
|
|
function createCloneToken(
|
|
string _cloneTokenName,
|
|
uint8 _cloneDecimalUnits,
|
|
string _cloneTokenSymbol,
|
|
uint _snapshotBlock,
|
|
bool _transfersEnabled
|
|
)
|
|
public
|
|
returns(address)
|
|
{
|
|
uint snapshotBlock = _snapshotBlock;
|
|
if (snapshotBlock == 0) {
|
|
snapshotBlock = block.number;
|
|
}
|
|
MiniMeToken cloneToken = tokenFactory.createCloneToken(
|
|
this,
|
|
snapshotBlock,
|
|
_cloneTokenName,
|
|
_cloneDecimalUnits,
|
|
_cloneTokenSymbol,
|
|
_transfersEnabled
|
|
);
|
|
|
|
cloneToken.changeController(msg.sender);
|
|
|
|
// An event to make the token easy to find on the blockchain
|
|
emit NewCloneToken(address(cloneToken), snapshotBlock);
|
|
return address(cloneToken);
|
|
}
|
|
|
|
////////////////
|
|
// Generate and destroy tokens
|
|
////////////////
|
|
|
|
/**
|
|
* @notice Generates `_amount` tokens that are assigned to `_owner`
|
|
* @param _owner The address that will be assigned the new tokens
|
|
* @param _amount The quantity of tokens generated
|
|
* @return True if the tokens are generated correctly
|
|
*/
|
|
function generateTokens(
|
|
address _owner,
|
|
uint _amount
|
|
)
|
|
public
|
|
// onlyController TODO: UNCOMMENT THIS. THIS WAS DISABLED FOR DEMO PURPOSES
|
|
returns (bool)
|
|
{
|
|
uint curTotalSupply = totalSupplyAt(block.number);
|
|
require(curTotalSupply + _amount >= curTotalSupply); // Check for overflow
|
|
uint previousBalanceTo = balanceOfAt(_owner, block.number);
|
|
require(previousBalanceTo + _amount >= previousBalanceTo); // Check for overflow
|
|
updateValueAtNow(totalSupplyHistory, curTotalSupply + _amount);
|
|
updateValueAtNow(balances[_owner], previousBalanceTo + _amount);
|
|
emit Transfer(0, _owner, _amount);
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* @notice Burns `_amount` tokens from `_owner`
|
|
* @param _owner The address that will lose the tokens
|
|
* @param _amount The quantity of tokens to burn
|
|
* @return True if the tokens are burned correctly
|
|
*/
|
|
function destroyTokens(
|
|
address _owner,
|
|
uint _amount
|
|
)
|
|
public
|
|
onlyController
|
|
returns (bool)
|
|
{
|
|
uint curTotalSupply = totalSupplyAt(block.number);
|
|
require(curTotalSupply >= _amount);
|
|
uint previousBalanceFrom = balanceOfAt(_owner, block.number);
|
|
require(previousBalanceFrom >= _amount);
|
|
updateValueAtNow(totalSupplyHistory, curTotalSupply - _amount);
|
|
updateValueAtNow(balances[_owner], previousBalanceFrom - _amount);
|
|
emit Transfer(_owner, 0, _amount);
|
|
return true;
|
|
}
|
|
|
|
////////////////
|
|
// Enable tokens transfers
|
|
////////////////
|
|
|
|
/**
|
|
* @notice Enables token holders to transfer their tokens freely if true
|
|
* @param _transfersEnabled True if transfers are allowed in the clone
|
|
*/
|
|
function enableTransfers(bool _transfersEnabled) public onlyController {
|
|
transfersEnabled = _transfersEnabled;
|
|
}
|
|
|
|
////////////////
|
|
// Internal helper functions to query and set a value in a snapshot array
|
|
////////////////
|
|
|
|
/**
|
|
* @dev `getValueAt` retrieves the number of tokens at a given block number
|
|
* @param checkpoints The history of values being queried
|
|
* @param _block The block number to retrieve the value at
|
|
* @return The number of tokens being queried
|
|
*/
|
|
function getValueAt(
|
|
Checkpoint[] storage checkpoints,
|
|
uint _block
|
|
)
|
|
constant
|
|
internal
|
|
returns (uint)
|
|
{
|
|
if (checkpoints.length == 0) {
|
|
return 0;
|
|
}
|
|
|
|
// Shortcut for the actual value
|
|
if (_block >= checkpoints[checkpoints.length-1].fromBlock) {
|
|
return checkpoints[checkpoints.length-1].value;
|
|
}
|
|
if (_block < checkpoints[0].fromBlock) {
|
|
return 0;
|
|
}
|
|
|
|
// Binary search of the value in the array
|
|
uint min = 0;
|
|
uint max = checkpoints.length-1;
|
|
while (max > min) {
|
|
uint mid = (max + min + 1) / 2;
|
|
if (checkpoints[mid].fromBlock<=_block) {
|
|
min = mid;
|
|
} else {
|
|
max = mid-1;
|
|
}
|
|
}
|
|
return checkpoints[min].value;
|
|
}
|
|
|
|
/**
|
|
* @dev `updateValueAtNow` used to update the `balances` map and the
|
|
* `totalSupplyHistory`
|
|
* @param checkpoints The history of data being updated
|
|
* @param _value The new number of tokens
|
|
*/
|
|
function updateValueAtNow(Checkpoint[] storage checkpoints, uint _value) internal {
|
|
if ((checkpoints.length == 0)
|
|
|| (checkpoints[checkpoints.length -1].fromBlock < block.number)) {
|
|
Checkpoint storage newCheckPoint = checkpoints[checkpoints.length++];
|
|
newCheckPoint.fromBlock = uint128(block.number);
|
|
newCheckPoint.value = uint128(_value);
|
|
} else {
|
|
Checkpoint storage oldCheckPoint = checkpoints[checkpoints.length-1];
|
|
oldCheckPoint.value = uint128(_value);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @dev Internal function to determine if an address is a contract
|
|
* @param _addr The address being queried
|
|
* @return True if `_addr` is a contract
|
|
*/
|
|
function isContract(address _addr) internal view returns(bool) {
|
|
uint size;
|
|
if (_addr == 0){
|
|
return false;
|
|
}
|
|
assembly {
|
|
size := extcodesize(_addr)
|
|
}
|
|
return size>0;
|
|
}
|
|
|
|
/**
|
|
* @dev Helper function to return a min betwen the two uints
|
|
*/
|
|
function min(uint a, uint b) internal returns (uint) {
|
|
return a < b ? a : b;
|
|
}
|
|
|
|
/**
|
|
* @notice The fallback function: If the contract's controller has not been
|
|
* set to 0, then the `proxyPayment` method is called which relays the
|
|
* ether and creates tokens as described in the token controller contract
|
|
*/
|
|
function () public payable {
|
|
require(isContract(controller));
|
|
require(TokenController(controller).proxyPayment.value(msg.value)(msg.sender));
|
|
}
|
|
|
|
//////////
|
|
// Safety Methods
|
|
//////////
|
|
|
|
/**
|
|
* @notice This method can be used by the controller to extract mistakenly
|
|
* sent tokens to this contract.
|
|
* @param _token The address of the token contract that you want to recover
|
|
* set to 0 in case you want to extract ether.
|
|
*/
|
|
function claimTokens(address _token) public onlyController {
|
|
if (_token == 0x0) {
|
|
controller.transfer(address(this).balance);
|
|
return;
|
|
}
|
|
|
|
MiniMeToken token = MiniMeToken(_token);
|
|
uint balance = token.balanceOf(address(this));
|
|
token.transfer(controller, balance);
|
|
emit ClaimedTokens(_token, controller, balance);
|
|
}
|
|
|
|
////////////////
|
|
// Events
|
|
////////////////
|
|
event ClaimedTokens(address indexed _token, address indexed _controller, uint _amount);
|
|
event Transfer(address indexed _from, address indexed _to, uint256 _amount);
|
|
event NewCloneToken(address indexed _cloneToken, uint snapshotBlock);
|
|
event Approval(
|
|
address indexed _owner,
|
|
address indexed _spender,
|
|
uint256 _amount
|
|
);
|
|
|
|
}
|