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Added comments and tried to understand it! 

I pretty much get the entire contract and it looks great... i made a few random changes to where isConstant is used in the last commit... but other then that the code was left untouched. I do think the Owned and Owner should be renamed to Controlled and Controller to avoid confusion with _owner which is used all over the place...
This commit is contained in:
Griff Green 2016-11-11 11:24:16 +01:00 committed by GitHub
parent e435143aa7
commit d72fe99605
1 changed files with 124 additions and 55 deletions
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179
MiniMeToken.sol
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@ -18,6 +18,13 @@
pragma solidity ^0.4.4;
/// @title MiniMeToken Contract
/// @author Jordi Baylina
/// @dev This token contract's goal is to make it easy to clone this token to
/// spawn child tokens using the token distribution at a given block.
/// @dev It is ERC 20 compliant, but still needs to under go further testing.
contract Owned {
/// @notice The address of the owner is the only address that can call a
/// function with this modifier
@ -44,7 +51,7 @@ contract MiniMeToken is Owned {
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 = 'H0.1'; //An arbitrary versioning scheme.
string public version = 'MMT_0.1'; //An arbitrary versioning scheme.
/// @dev `Checkpoint` is the structure that attaches a block number to the a
@ -54,7 +61,7 @@ contract MiniMeToken is Owned {
// `fromBlock` is the block number that the value was generated from
uint fromBlock;
// `value` is the attribute in question at a specific block number
// `value` is the amount of tokens at a specific block number
uint value;
}
@ -101,7 +108,7 @@ contract MiniMeToken is Owned {
uint8 _decimalUnits,
string _tokenSymbol,
bool _isConstant
) {
) {
tokenFactory = MiniMeTokenFactory(_tokenFactory);
name = _tokenName; // Set the name
decimals = _decimalUnits; // Set the decimals
@ -132,8 +139,8 @@ contract MiniMeToken is Owned {
/// @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)
returns (bool success) {
function transferFrom(address _from, address _to, uint256 _amount
) returns (bool success) {
// The owner of this contract can move tokens around at will, this is
// important to recognize! Confirm that you trust the owner of this
@ -149,7 +156,8 @@ contract MiniMeToken is Owned {
return doTransfer(_from, _to, _amount);
}
function doTransfer(address _from, address _to, uint _amount) internal returns(bool) {
function doTransfer(address _from, address _to, uint _amount
) internal returns(bool) {
if (_amount == 0) {
return true;
@ -180,8 +188,8 @@ contract MiniMeToken is Owned {
return true;
}
/// @param _owner The address from which the balance will be retrieved
/// @return The balance
/// @param _owner The address that's balance is being requested
/// @return The balance of `_owner` at the current block
function balanceOf(address _owner) constant returns (uint256 balance) {
return balanceOfAt(_owner, block.number);
}
@ -190,7 +198,7 @@ contract MiniMeToken is Owned {
/// its behalf
/// @param _spender The address of the account able to transfer the tokens
/// @param _amount The amount of tokens to be approved for transfer
/// @return Whether the approval was successful or not
/// @return True if the approval was successful
function approve(address _spender, uint256 _amount) returns (bool success) {
if (isConstant) throw;
allowed[msg.sender][_spender] = _amount;
@ -198,28 +206,45 @@ contract MiniMeToken is Owned {
return true;
}
/// @param _owner The address of the account owning tokens
/// @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) constant returns (uint256 remaining) {
return allowed[_owner][_spender];
function allowance(address _owner, address _spender
) constant returns (uint256 remaining) {
return allowed[_owner][_spender];
}
/* Approves and then calls the receiving contract (Copied from the Consensis Standard contract) */
function approveAndCall(address _spender, uint256 _amount, bytes _extraData) returns (bool success) {
/// @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`
/// @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
) returns (bool success) {
if (isConstant) throw;
allowed[msg.sender][_spender] = _amount;
Approval(msg.sender, _spender, _amount);
//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.
//receiveApproval(address _from, uint256 _amount, address _tokenContract, bytes _extraData)
//it is assumed that when does this that the call *should* succeed, otherwise one would use vanilla approve instead.
if(!_spender.call(bytes4(bytes32(sha3("receiveApproval(address,uint256,address,bytes)"))), msg.sender, _amount, this, _extraData)) { throw; }
// This portion is copied from ConsenSys's Standard Token Contract. It
// calls the receiveApproval function that is part of the contract that
// is being approved (`_spender`). The function should look like:
// `receiveApproval(address _from, uint256 _amount, address
// _tokenContract, bytes _extraData)` It is assumed that the call
// *should* succeed, otherwise one would use vanilla approve instead.
if(!_spender.call(
bytes4(bytes32(sha3("receiveApproval(address,uint256,address,bytes)"))),
msg.sender,
_amount,
this,
_extraData
)) { throw;
}
return true;
}
/// @return Total amount of tokens
/// @return The total amount of tokens
function totalSupply() constant returns (uint) {
return totalSupplyAt(block.number);
}
@ -229,22 +254,22 @@ contract MiniMeToken is Owned {
// Query balance and totalSupply in History
////////////////
/// @notice Queries the balance of `_owner` at a specific `_blockNumber`.
/// @notice Queries the balance of `_owner` at a specific `_blockNumber`
/// @param _owner The address from which the balance will be retrieved
/// @param _blockNumber block number when the balance is queried
/// @param _blockNumber The block number when the balance is queried
/// @return The balance at `_blockNumber`
function balanceOfAt(address _owner, uint _blockNumber) constant
returns (uint) {
// If the _blockNumber requested is before the genesis block for the
// `parentToken` the value returned is 0
// If the `_blockNumber` requested is before the genesis block for the
// the token being queried, the value returned is 0
if (_blockNumber < creationBlock) {
return 0;
// 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 this token as this contains initial balance of this token.
// block for that token as this contains initial balance of this token.
} else if ((balances[_owner].length == 0)
|| (balances[_owner][0].fromBlock > _blockNumber)) {
if (address(parentToken) != 0) {
@ -261,17 +286,29 @@ contract MiniMeToken is Owned {
}
/// @notice Total amount of tokens at a specific `_blockNumber`.
/// @param _blockNumber block number when the totalSupply is queried
/// @return Total amounts of token at `_blockNumber`
/// @param _blockNumber The block number when the totalSupply is queried
/// @return The total amount of tokens at `_blockNumber`
function totalSupplyAt(uint _blockNumber) constant returns(uint) {
// If the `_blockNumber` requested is before the genesis block for the
// the token being queried, the value returned is 0
if (_blockNumber < creationBlock) {
return 0;
} else if ((totalSupplyHistory.length == 0) || (totalSupplyHistory[0].fromBlock > _blockNumber)) {
// 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.
} else if ((totalSupplyHistory.length == 0)
|| (totalSupplyHistory[0].fromBlock > _blockNumber)) {
if (address(parentToken) != 0) {
return parentToken.totalSupplyAt(parentSnapShotBlock);
} else {
return 0;
}
// This will return the expected totalSupply during normal situations
} else {
return getValueAt( totalSupplyHistory, _blockNumber);
}
@ -281,20 +318,34 @@ contract MiniMeToken is Owned {
// Create a child token from an snapshot of this token at a given block
////////////////
/// @notice creates a new child token with the initial distribution the same
/// that this token at `_snapshotBlock`
/// @notice Creates a new child token with the initial distribution being
/// this token at `_snapshotBlock`
/// @param _childTokenName Name of the child token
/// @param _childDecimalUnits Units of the child token
/// @param _childTokenSymbol Symbol of the child token
/// @param _snapshotBlock Block at when the the distribution of the parent
/// token is taken as the initial thistribution of the new generated token.
/// If the block is higher that the actual block, the actual block is token
/// @param _isConstant Sets if the new child contract will allow transfers
/// or not.
/// @param _snapshotBlock Block when the distribution of the parent token is
/// copied to set the initial distribution of the new child token;
/// if the block is higher than the actual block, the current block is used
/// @param _isConstant True if transfers are not allowed in the child token
/// @return The address of the new MiniMeToken Contract
function createChildToken(string _childTokenName, uint8 _childDecimalUnits, string _childTokenSymbol, uint _snapshotBlock, bool _isConstant) returns(address) {
function createChildToken(
string _childTokenName,
uint8 _childDecimalUnits,
string _childTokenSymbol,
uint _snapshotBlock,
bool _isConstant
) returns(address) {
if (_snapshotBlock > block.number) _snapshotBlock = block.number;
MiniMeToken childToken = tokenFactory.createChildToken(this, _snapshotBlock, _childTokenName, _childDecimalUnits, _childTokenSymbol, _isConstant);
MiniMeToken childToken = tokenFactory.createChildToken(
this,
_snapshotBlock,
_childTokenName,
_childDecimalUnits,
_childTokenSymbol,
_isConstant
);
// An event to make the token easy to find on the blockchain
NewChildToken(address(childToken), _snapshotBlock);
return address(childToken);
}
@ -303,11 +354,12 @@ contract MiniMeToken is Owned {
// Generate and destroy tokens
////////////////
/// @notice generates `_amount` tokens that are assigned to `_owner`
/// @param _owner address of the owner who the new tokens will be assigned
/// @param _amount quantity of tokens generated
/// @return true if the tokens are generated correctly
function generateTokens(address _owner, uint _amount) onlyOwner returns (bool) {
/// @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
) onlyOwner returns (bool) {
uint curTotalSupply = getValueAt(totalSupplyHistory, block.number);
updateValueAtNow(totalSupplyHistory, curTotalSupply + _amount);
var previousBalanceTo = balanceOf(_owner);
@ -317,11 +369,12 @@ contract MiniMeToken is Owned {
}
/// @notice destroy `_amount` tokens from `_owner`
/// @param _owner address who the tokens are destroyed from
/// @param _amount Quantity of tokens to destroy
/// @return true if the tokens are removed correctly
function destroyTokens(address _owner, uint _amount) onlyOwner returns (bool) {
/// @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
) onlyOwner returns (bool) {
uint curTotalSupply = getValueAt(totalSupplyHistory, block.number);
if (curTotalSupply < _amount) throw;
updateValueAtNow(totalSupplyHistory, curTotalSupply - _amount);
@ -347,10 +400,12 @@ contract MiniMeToken is Owned {
// Internal helper functions to query and set a value in a snapshot array
////////////////
function getValueAt(Checkpoint[] storage checkpoints, uint _block) constant internal returns (uint) {
function getValueAt(Checkpoint[] storage checkpoints, uint _block
) constant internal returns (uint) {
if (checkpoints.length == 0) return 0;
// Shorcut for the actual value
if (_block >= checkpoints[checkpoints.length-1].fromBlock) return checkpoints[checkpoints.length-1].value;
if (_block >= checkpoints[checkpoints.length-1].fromBlock)
return checkpoints[checkpoints.length-1].value;
if (_block < checkpoints[0].fromBlock) return 0;
uint min = 0;
uint max = checkpoints.length-1;
@ -365,8 +420,10 @@ contract MiniMeToken is Owned {
return checkpoints[min].value;
}
function updateValueAtNow(Checkpoint[] storage checkpoints, uint _value) internal {
if ((checkpoints.length == 0) || (checkpoints[checkpoints.length -1].fromBlock < block.number)) {
function updateValueAtNow(Checkpoint[] storage checkpoints, uint _value
) internal {
if ((checkpoints.length == 0)
|| (checkpoints[checkpoints.length -1].fromBlock < block.number)) {
Checkpoint newCheckPoint = checkpoints[ checkpoints.length++ ];
newCheckPoint.fromBlock = block.number;
newCheckPoint.value = _value;
@ -376,9 +433,9 @@ contract MiniMeToken is Owned {
}
}
/// @notice Default method. If the contract has an owner, the Ether is sent
/// to the owner thru `proxyPayment` method. Generally, the owner will be
/// the contract responsable for the creation of the tokens.
/// @notice The fallback function: If the contract's owner has not been set
/// to 0, the ether is sent to the owner (normally the token creation
/// contract) using the `proxyPayment` method.
function () payable {
if (owner == 0) throw;
if (! TokenCreation(owner).proxyPayment.value(msg.value)(msg.sender)) {
@ -391,8 +448,12 @@ contract MiniMeToken is Owned {
// Events
////////////////
event Transfer(address indexed _from, address indexed _to, uint256 _amount);
event Approval(address indexed _owner, address indexed _spender, uint256 _amount);
event NewChildToken(address indexed _childToken, uint _snapshotBlock);
event Approval(
address indexed _owner,
address indexed _spender,
uint256 _amount
);
}
@ -405,7 +466,15 @@ contract MiniMeTokenFactory {
string _tokenSymbol,
bool _isConstant
) returns (MiniMeToken) {
MiniMeToken newToken = new MiniMeToken(this, _parentToken, _snapshotBlock, _tokenName, _decimalUnits, _tokenSymbol, _isConstant);
MiniMeToken newToken = new MiniMeToken(
this,
_parentToken,
_snapshotBlock,
_tokenName,
_decimalUnits,
_tokenSymbol,
_isConstant
);
return newToken;
}
}