mirror of https://github.com/vacp2p/minime.git
412 lines
16 KiB
Solidity
412 lines
16 KiB
Solidity
/*
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Copyright 2016, Jordi Baylina
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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pragma solidity ^0.4.4;
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contract Owned {
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/// @notice The address of the owner is the only address that can call a
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/// function with this modifier
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modifier onlyOwner { if (msg.sender != owner) throw; _; }
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address public owner;
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/// @return Returns the owner of this token
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function Owned() { owner = msg.sender;}
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/// @notice Changes the owner of the contract
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/// @param _newOwner The new owner of the contract
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function changeOwner(address _newOwner) onlyOwner {
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owner = _newOwner;
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}
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}
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contract TokenCreation {
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function proxyPayment(address _owner) payable returns(bool);
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}
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contract MiniMeToken is Owned {
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string public name; //The Token's name: e.g. DigixDAO Tokens
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uint8 public decimals; //Number of decimals of the smallest unit
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string public symbol; //An identifier: e.g. REP
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string public version = 'H0.1'; //An arbitrary versioning scheme.
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/// @dev `Checkpoint` is the structure that attaches a block number to the a
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/// given token attribute
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struct Checkpoint {
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// `fromBlock` is the block number that the value was generated from
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uint fromBlock;
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// `value` is the attribute in question at a specific block number
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uint value;
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}
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// `parentToken` is the Token address that was cloned. 0x0 for a root token
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MiniMeToken public parentToken;
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// `parentSnapShotBlock` is the Block number from the Parent Token that was
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// used to determine the initial distribution of the Cloned Token.
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uint public parentSnapShotBlock;
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// `creationBlock` is the block number that the Cloned Token was created
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uint public creationBlock;
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// `balances` is the map that tracks the balance of each address
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mapping (address => Checkpoint[]) balances;
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// `allowed` tracks any extra transfer rights as in all ERC20 tokens
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mapping (address => mapping (address => uint256)) allowed;
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Checkpoint[] totalSupplyHistory;
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bool public isConstant;
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MiniMeTokenFactory public tokenFactory;
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////////////////
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// Constructor
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////////////////
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/// @notice Constructor to create a MiniMeToken
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/// @param _tokenFactory The address of the MiniMeTokenFactory contract that
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/// will create the Cloned token contracts
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/// @param _parentToken Address of the parent token, set to 0x0 if it is a
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/// new token
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/// @param _parentSnapShotBlock Block of the parent token that will
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/// determine the initial distribution of the cloned token
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/// @param _tokenName Name of the new token
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/// @param _decimalUnits Number of decimals of the new token
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/// @param _tokenSymbol Token Symbol for the new token
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/// @param _isConstant If true, tokens will not be able to be transferred
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function MiniMeToken(
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address _tokenFactory,
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address _parentToken,
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uint _parentSnapShotBlock,
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string _tokenName,
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uint8 _decimalUnits,
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string _tokenSymbol,
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bool _isConstant
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) {
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tokenFactory = MiniMeTokenFactory(_tokenFactory);
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name = _tokenName; // Set the name
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decimals = _decimalUnits; // Set the decimals
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symbol = _tokenSymbol; // Set the symbol
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parentToken = MiniMeToken(_parentToken);
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parentSnapShotBlock = _parentSnapShotBlock;
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isConstant = _isConstant;
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creationBlock = block.number;
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}
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///////////////////
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// ERC20 Functions
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///////////////////
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/// @notice Send `_amount` tokens to `_to` from `msg.sender`
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/// @param _to The address of the recipient
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/// @param _amount The amount of tokens to be transferred
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/// @return Whether the transfer was successful or not
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function transfer(address _to, uint256 _amount) returns (bool success) {
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if (isConstant) throw;
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return doTransfer(msg.sender, _to, _amount);
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}
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/// @notice Send `_amount` tokens to `_to` from `_from` on the condition it
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/// is approved by `_from`
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/// @param _from The address holding the tokens being transferred
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/// @param _to The address of the recipient
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/// @param _amount The amount of tokens to be transferred
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/// @return True if the transfer was successful
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function transferFrom(address _from, address _to, uint256 _amount)
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returns (bool success) {
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// The owner of this contract can move tokens around at will, this is
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// important to recognize! Confirm that you trust the owner of this
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// contract, which in most situations should be another open source
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// smart contract or 0x0
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if (msg.sender != owner) {
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if (isConstant) throw;
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// The standard ERC 20 transferFrom functionality
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if (allowed[_from][msg.sender] < _amount) return false;
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allowed[_from][msg.sender] -= _amount;
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}
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return doTransfer(_from, _to, _amount);
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}
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function doTransfer(address _from, address _to, uint _amount) internal returns(bool) {
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if (_amount == 0) {
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return true;
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}
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// Do not allow transfer to 0x0 or the token contract itself
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if ((_to == 0) || (_to == address(this))) throw;
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// If the amount being transfered is more than the balance of the
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// account the transfer returns false
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var previousBalanceFrom = balanceOfAt(_from, block.number);
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if (previousBalanceFrom < _amount) {
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return false;
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}
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// First update the balance array with the new value for the address
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// sending the tokens
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updateValueAtNow(balances[_from], previousBalanceFrom - _amount);
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// Then update the balance array with the new value for the address
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// receiving the tokens
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var previousBalanceTo = balanceOfAt(_to, block.number);
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updateValueAtNow(balances[_to], previousBalanceTo + _amount);
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// An event to make the transfer easy to find on the blockchain
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Transfer(_from, _to, _amount);
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return true;
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}
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/// @param _owner The address from which the balance will be retrieved
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/// @return The balance
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function balanceOf(address _owner) constant returns (uint256 balance) {
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return balanceOfAt(_owner, block.number);
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}
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/// @notice `msg.sender` approves `_spender` to spend `_amount` tokens on
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/// its behalf
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/// @param _spender The address of the account able to transfer the tokens
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/// @param _amount The amount of tokens to be approved for transfer
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/// @return Whether the approval was successful or not
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function approve(address _spender, uint256 _amount) returns (bool success) {
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if (isConstant) throw;
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allowed[msg.sender][_spender] = _amount;
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Approval(msg.sender, _spender, _amount);
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return true;
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}
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/// @param _owner The address of the account owning tokens
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/// @param _spender The address of the account able to transfer the tokens
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/// @return Amount of remaining tokens of _owner that _spender is allowed
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/// to spend
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function allowance(address _owner, address _spender) constant returns (uint256 remaining) {
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return allowed[_owner][_spender];
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}
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/* Approves and then calls the receiving contract (Copied from the Consensis Standard contract) */
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function approveAndCall(address _spender, uint256 _amount, bytes _extraData) returns (bool success) {
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if (isConstant) throw;
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allowed[msg.sender][_spender] = _amount;
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Approval(msg.sender, _spender, _amount);
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//call the receiveApproval function on the contract you want to be notified. This crafts the function signature manually so one doesn't have to include a contract in here just for this.
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//receiveApproval(address _from, uint256 _amount, address _tokenContract, bytes _extraData)
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//it is assumed that when does this that the call *should* succeed, otherwise one would use vanilla approve instead.
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if(!_spender.call(bytes4(bytes32(sha3("receiveApproval(address,uint256,address,bytes)"))), msg.sender, _amount, this, _extraData)) { throw; }
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return true;
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}
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/// @return Total amount of tokens
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function totalSupply() constant returns (uint) {
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return totalSupplyAt(block.number);
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}
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////////////////
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// Query balance and totalSupply in History
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////////////////
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/// @notice Queries the balance of `_owner` at a specific `_blockNumber`.
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/// @param _owner The address from which the balance will be retrieved
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/// @param _blockNumber block number when the balance is queried
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/// @return The balance at `_blockNumber`
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function balanceOfAt(address _owner, uint _blockNumber) constant
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returns (uint) {
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// If the _blockNumber requested is before the genesis block for the
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// `parentToken` the value returned is 0
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if (_blockNumber < creationBlock) {
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return 0;
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// These next few lines are used when the balance of the token is
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// requested before a check point was ever created for this token, it
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// requires that the `parentToken.balanceOfAt` be queried at the genesis
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// block for this token as this contains initial balance of this token.
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} else if ((balances[_owner].length == 0)
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|| (balances[_owner][0].fromBlock > _blockNumber)) {
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if (address(parentToken) != 0) {
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return parentToken.balanceOfAt(_owner, parentSnapShotBlock);
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} else {
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return 0;
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}
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// This will return the expected balance during normal situations
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} else {
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return getValueAt( balances[_owner], _blockNumber);
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}
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}
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/// @notice Total amount of tokens at a specific `_blockNumber`.
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/// @param _blockNumber block number when the totalSupply is queried
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/// @return Total amounts of token at `_blockNumber`
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function totalSupplyAt(uint _blockNumber) constant returns(uint) {
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if (_blockNumber < creationBlock) {
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return 0;
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} else if ((totalSupplyHistory.length == 0) || (totalSupplyHistory[0].fromBlock > _blockNumber)) {
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if (address(parentToken) != 0) {
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return parentToken.totalSupplyAt(parentSnapShotBlock);
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} else {
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return 0;
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}
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} else {
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return getValueAt( totalSupplyHistory, _blockNumber);
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}
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}
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////////////////
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// Create a child token from an snapshot of this token at a given block
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////////////////
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/// @notice creates a new child token with the initial distribution the same
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/// that this token at `_snapshotBlock`
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/// @param _childTokenName Name of the child token
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/// @param _childDecimalUnits Units of the child token
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/// @param _childTokenSymbol Symbol of the child token
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/// @param _snapshotBlock Block at when the the distribution of the parent
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/// token is taken as the initial thistribution of the new generated token.
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/// If the block is higher that the actual block, the actual block is token
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/// @param _isConstant Sets if the new child contract will allow transfers
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/// or not.
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/// @return The address of the new MiniMeToken Contract
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function createChildToken(string _childTokenName, uint8 _childDecimalUnits, string _childTokenSymbol, uint _snapshotBlock, bool _isConstant) returns(address) {
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if (_snapshotBlock > block.number) _snapshotBlock = block.number;
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MiniMeToken childToken = tokenFactory.createChildToken(this, _snapshotBlock, _childTokenName, _childDecimalUnits, _childTokenSymbol, _isConstant);
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NewChildToken(address(childToken), _snapshotBlock);
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return address(childToken);
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}
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////////////////
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// Generate and destroy tokens
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////////////////
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/// @notice generates `_amount` tokens that are assigned to `_owner`
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/// @param _owner address of the owner who the new tokens will be assigned
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/// @param _amount quantity of tokens generated
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/// @return true if the tokens are generated correctly
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function generateTokens(address _owner, uint _amount) onlyOwner returns (bool) {
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uint curTotalSupply = getValueAt(totalSupplyHistory, block.number);
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updateValueAtNow(totalSupplyHistory, curTotalSupply + _amount);
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var previousBalanceTo = balanceOf(_owner);
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updateValueAtNow(balances[_owner], previousBalanceTo + _amount);
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Transfer(0, _owner, _amount);
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return true;
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}
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/// @notice destroy `_amount` tokens from `_owner`
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/// @param _owner address who the tokens are destroyed from
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/// @param _amount Quantity of tokens to destroy
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/// @return true if the tokens are removed correctly
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function destroyTokens(address _owner, uint _amount) onlyOwner returns (bool) {
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uint curTotalSupply = getValueAt(totalSupplyHistory, block.number);
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if (curTotalSupply < _amount) throw;
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updateValueAtNow(totalSupplyHistory, curTotalSupply - _amount);
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var previousBalanceFrom = balanceOf(_owner);
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if (previousBalanceFrom < _amount) throw;
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updateValueAtNow(balances[_owner], previousBalanceFrom - _amount);
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Transfer(_owner, 0, _amount);
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return true;
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}
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////////////////
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// Constant tokens
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////////////////
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/// @notice Sets if the contract is constant or not
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/// @param _isConstant true to don't allow transfers false to allow transfer
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function setConstant(bool _isConstant) onlyOwner {
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isConstant = _isConstant;
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}
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////////////////
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// Internal helper functions to query and set a value in a snapshot array
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////////////////
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function getValueAt(Checkpoint[] storage checkpoints, uint _block) constant internal returns (uint) {
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if (checkpoints.length == 0) return 0;
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// Shorcut for the actual value
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if (_block >= checkpoints[checkpoints.length-1].fromBlock) return checkpoints[checkpoints.length-1].value;
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if (_block < checkpoints[0].fromBlock) return 0;
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uint min = 0;
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uint max = checkpoints.length-1;
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while (max > min) {
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uint mid = (max + min + 1)/ 2;
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if (checkpoints[mid].fromBlock<=_block) {
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min = mid;
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} else {
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max = mid-1;
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}
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}
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return checkpoints[min].value;
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}
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function updateValueAtNow(Checkpoint[] storage checkpoints, uint _value) internal {
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if ((checkpoints.length == 0) || (checkpoints[checkpoints.length -1].fromBlock < block.number)) {
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Checkpoint newCheckPoint = checkpoints[ checkpoints.length++ ];
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newCheckPoint.fromBlock = block.number;
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newCheckPoint.value = _value;
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} else {
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Checkpoint oldCheckPoint = checkpoints[checkpoints.length-1];
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oldCheckPoint.value = _value;
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}
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}
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/// @notice Default method. If the contract has an owner, the Ether is sent
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/// to the owner thru `proxyPayment` method. Generally, the owner will be
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/// the contract responsable for the creation of the tokens.
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function () payable {
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if (owner == 0) throw;
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if (! TokenCreation(owner).proxyPayment.value(msg.value)(msg.sender)) {
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throw;
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}
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}
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////////////////
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// Events
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////////////////
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event Transfer(address indexed _from, address indexed _to, uint256 _amount);
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event Approval(address indexed _owner, address indexed _spender, uint256 _amount);
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event NewChildToken(address indexed _childToken, uint _snapshotBlock);
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}
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contract MiniMeTokenFactory {
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function createChildToken(
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address _parentToken,
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uint _snapshotBlock,
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string _tokenName,
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uint8 _decimalUnits,
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string _tokenSymbol,
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bool _isConstant
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) returns (MiniMeToken) {
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MiniMeToken newToken = new MiniMeToken(this, _parentToken, _snapshotBlock, _tokenName, _decimalUnits, _tokenSymbol, _isConstant);
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return newToken;
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}
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}
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