Merge pull request #85 from binance-chain/mirror-sync

R4R: add Mirror/Sync feature, implementation of BEP84

contracts/TokenHub.sol

@@ -66,7 +66,7 @@ contract TokenHub is ITokenHub, System, IParamSubscriber, IApplication, ISystemR
   uint8 constant public   TRANSFER_IN_FAILURE_UNKNOWN = 5;
 
   uint256 constant public MAX_BEP2_TOTAL_SUPPLY = 9000000000000000000;
-  uint8 constant public   MINIMUM_BEP20_SYMBOL_LEN = 3;
+  uint8 constant public   MINIMUM_BEP20_SYMBOL_LEN = 2;
   uint8 constant public   MAXIMUM_BEP20_SYMBOL_LEN = 8;
   uint8 constant public   BEP2_TOKEN_DECIMALS = 8;
   bytes32 constant public BEP2_TOKEN_SYMBOL_FOR_BNB = 0x424E420000000000000000000000000000000000000000000000000000000000; // "BNB"
@@ -333,7 +333,7 @@ contract TokenHub is ITokenHub, System, IParamSubscriber, IApplication, ISystemR
       }
       idx++;
     }
-    return (transOutSynPkg, true);
+    return (transOutSynPkg, success);
   }
 
   function handleTransferOutFailAckPackage(bytes memory msgBytes) internal {

contracts/TokenHub.template

@@ -66,7 +66,7 @@ contract TokenHub is ITokenHub, System, IParamSubscriber, IApplication, ISystemR
   uint8 constant public   TRANSFER_IN_FAILURE_UNKNOWN = 5;
 
   uint256 constant public MAX_BEP2_TOTAL_SUPPLY = 9000000000000000000;
-  uint8 constant public   MINIMUM_BEP20_SYMBOL_LEN = 3;
+  uint8 constant public   MINIMUM_BEP20_SYMBOL_LEN = 2;
   uint8 constant public   MAXIMUM_BEP20_SYMBOL_LEN = 8;
   uint8 constant public   BEP2_TOKEN_DECIMALS = 8;
   bytes32 constant public BEP2_TOKEN_SYMBOL_FOR_BNB = 0x424E420000000000000000000000000000000000000000000000000000000000; // "BNB"
@@ -333,7 +333,7 @@ contract TokenHub is ITokenHub, System, IParamSubscriber, IApplication, ISystemR
       }
       idx++;
     }
-    return (transOutSynPkg, true);
+    return (transOutSynPkg, success);
   }
 
   function handleTransferOutFailAckPackage(bytes memory msgBytes) internal {

contracts/test/XYZToken.sol

@@ -0,0 +1,298 @@
+pragma solidity 0.6.4;
+
+import "../interface/IBEP20.sol";
+import "openzeppelin-solidity/contracts/GSN/Context.sol";
+import "openzeppelin-solidity/contracts/math/SafeMath.sol";
+import "openzeppelin-solidity/contracts/access/Ownable.sol";
+
+contract XYZToken is Context, IBEP20, Ownable {
+  using SafeMath for uint256;
+
+  mapping (address => uint256) private _balances;
+
+  mapping (address => mapping (address => uint256)) private _allowances;
+
+  uint256 private _totalSupply;
+  uint8 private _decimals;
+  string private _symbol;
+  string private _name;
+
+  constructor() public {
+    _name = "XYZ token";
+    _symbol = "XYZ";
+    _decimals = 18;
+    _totalSupply = 100000000000000000000000000;
+    _balances[msg.sender] = _totalSupply;
+
+    emit Transfer(address(0), msg.sender, _totalSupply);
+  }
+
+  /**
+   * @dev Just for test
+   *
+   * - `newName` new name
+   */
+  function setName(string calldata newName) external {
+    _name = newName;
+  }
+
+  /**
+   * @dev Just for test
+   *
+   * - `newDecimals` new decimals
+   */
+  function setDecimals(uint8 newDecimals) external {
+    _decimals = newDecimals;
+  }
+
+  /**
+   * @dev Just for test
+   *
+   * - `newTotalSupply` new totalSupply
+   */
+  function setTotalSupply(uint256 newTotalSupply) external {
+    _totalSupply = newTotalSupply;
+  }
+
+
+  /**
+   * @dev Just for test
+   *
+   * - `newSymbol` new symbol
+   */
+  function setSymbol(string calldata newSymbol) external {
+    _symbol = newSymbol;
+  }
+
+  /**
+   * @dev Returns the bep token owner.
+   */
+  function getOwner() external override view returns (address) {
+    return owner();
+  }
+
+  /**
+   * @dev Returns the token decimals.
+   */
+  function decimals() external override view returns (uint8) {
+    return _decimals;
+  }
+
+  /**
+   * @dev Returns the token symbol.
+   */
+  function symbol() external override view returns (string memory) {
+    return _symbol;
+  }
+
+  /**
+  * @dev Returns the token name.
+  */
+  function name() external override view returns (string memory) {
+    return _name;
+  }
+
+  /**
+   * @dev See {BEP20-totalSupply}.
+   */
+  function totalSupply() external override view returns (uint256) {
+    return _totalSupply;
+  }
+
+  /**
+   * @dev See {BEP20-balanceOf}.
+   */
+  function balanceOf(address account) external override view returns (uint256) {
+    return _balances[account];
+  }
+
+  /**
+   * @dev See {BEP20-transfer}.
+   *
+   * Requirements:
+   *
+   * - `recipient` cannot be the zero address.
+   * - the caller must have a balance of at least `amount`.
+   */
+  function transfer(address recipient, uint256 amount) external override returns (bool) {
+    _transfer(_msgSender(), recipient, amount);
+    return true;
+  }
+
+  /**
+   * @dev See {BEP20-allowance}.
+   */
+  function allowance(address owner, address spender) external override view returns (uint256) {
+    return _allowances[owner][spender];
+  }
+
+  /**
+   * @dev See {BEP20-approve}.
+   *
+   * Requirements:
+   *
+   * - `spender` cannot be the zero address.
+   */
+  function approve(address spender, uint256 amount) external override returns (bool) {
+    _approve(_msgSender(), spender, amount);
+    return true;
+  }
+
+  /**
+   * @dev See {BEP20-transferFrom}.
+   *
+   * Emits an {Approval} event indicating the updated allowance. This is not
+   * required by the EIP. See the note at the beginning of {BEP20};
+   *
+   * Requirements:
+   * - `sender` and `recipient` cannot be the zero address.
+   * - `sender` must have a balance of at least `amount`.
+   * - the caller must have allowance for `sender`'s tokens of at least
+   * `amount`.
+   */
+  function transferFrom(address sender, address recipient, uint256 amount) external override returns (bool) {
+    _transfer(sender, recipient, amount);
+    _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "BEP20: transfer amount exceeds allowance"));
+    return true;
+  }
+
+  /**
+   * @dev Atomically increases the allowance granted to `spender` by the caller.
+   *
+   * This is an alternative to {approve} that can be used as a mitigation for
+   * problems described in {BEP20-approve}.
+   *
+   * Emits an {Approval} event indicating the updated allowance.
+   *
+   * Requirements:
+   *
+   * - `spender` cannot be the zero address.
+   */
+  function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
+    _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
+    return true;
+  }
+
+  /**
+   * @dev Atomically decreases the allowance granted to `spender` by the caller.
+   *
+   * This is an alternative to {approve} that can be used as a mitigation for
+   * problems described in {BEP20-approve}.
+   *
+   * Emits an {Approval} event indicating the updated allowance.
+   *
+   * Requirements:
+   *
+   * - `spender` cannot be the zero address.
+   * - `spender` must have allowance for the caller of at least
+   * `subtractedValue`.
+   */
+  function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
+    _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "BEP20: decreased allowance below zero"));
+    return true;
+  }
+
+  /**
+   * @dev Creates `amount` tokens and assigns them to `msg.sender`, increasing
+   * the total supply.
+   *
+   * Requirements
+   *
+   * - `msg.sender` must be the token owner
+   */
+  function mint(uint256 amount) public onlyOwner returns (bool) {
+    _mint(_msgSender(), amount);
+    return true;
+  }
+
+  /**
+   * @dev Moves tokens `amount` from `sender` to `recipient`.
+   *
+   * This is internal function is equivalent to {transfer}, and can be used to
+   * e.g. implement automatic token fees, slashing mechanisms, etc.
+   *
+   * Emits a {Transfer} event.
+   *
+   * Requirements:
+   *
+   * - `sender` cannot be the zero address.
+   * - `recipient` cannot be the zero address.
+   * - `sender` must have a balance of at least `amount`.
+   */
+  function _transfer(address sender, address recipient, uint256 amount) internal {
+    require(sender != address(0), "BEP20: transfer from the zero address");
+    require(recipient != address(0), "BEP20: transfer to the zero address");
+
+    _balances[sender] = _balances[sender].sub(amount, "BEP20: transfer amount exceeds balance");
+    _balances[recipient] = _balances[recipient].add(amount);
+    emit Transfer(sender, recipient, amount);
+  }
+
+  /** @dev Creates `amount` tokens and assigns them to `account`, increasing
+   * the total supply.
+   *
+   * Emits a {Transfer} event with `from` set to the zero address.
+   *
+   * Requirements
+   *
+   * - `to` cannot be the zero address.
+   */
+  function _mint(address account, uint256 amount) internal {
+    require(account != address(0), "BEP20: mint to the zero address");
+
+    _totalSupply = _totalSupply.add(amount);
+    _balances[account] = _balances[account].add(amount);
+    emit Transfer(address(0), account, amount);
+  }
+
+  /**
+   * @dev Destroys `amount` tokens from `account`, reducing the
+   * total supply.
+   *
+   * Emits a {Transfer} event with `to` set to the zero address.
+   *
+   * Requirements
+   *
+   * - `account` cannot be the zero address.
+   * - `account` must have at least `amount` tokens.
+   */
+  function _burn(address account, uint256 amount) internal {
+    require(account != address(0), "BEP20: burn from the zero address");
+
+    _balances[account] = _balances[account].sub(amount, "BEP20: burn amount exceeds balance");
+    _totalSupply = _totalSupply.sub(amount);
+    emit Transfer(account, address(0), amount);
+  }
+
+  /**
+   * @dev Sets `amount` as the allowance of `spender` over the `owner`s tokens.
+   *
+   * This is internal function is equivalent to `approve`, and can be used to
+   * e.g. set automatic allowances for certain subsystems, etc.
+   *
+   * Emits an {Approval} event.
+   *
+   * Requirements:
+   *
+   * - `owner` cannot be the zero address.
+   * - `spender` cannot be the zero address.
+   */
+  function _approve(address owner, address spender, uint256 amount) internal {
+    require(owner != address(0), "BEP20: approve from the zero address");
+    require(spender != address(0), "BEP20: approve to the zero address");
+
+    _allowances[owner][spender] = amount;
+    emit Approval(owner, spender, amount);
+  }
+
+  /**
+   * @dev Destroys `amount` tokens from `account`.`amount` is then deducted
+   * from the caller's allowance.
+   *
+   * See {_burn} and {_approve}.
+   */
+  function _burnFrom(address account, uint256 amount) internal {
+    _burn(account, amount);
+    _approve(account, _msgSender(), _allowances[account][_msgSender()].sub(amount, "BEP20: burn amount exceeds allowance"));
+  }
+}

migrations/2_deploy_contracts.js

@@ -23,6 +23,7 @@ const TokenHub = artifacts.require("TokenHub");
 const TokenManager = artifacts.require("TokenManager");
 const ABCToken = artifacts.require("test/ABCToken");
 const DEFToken = artifacts.require("test/DEFToken");
+const XYZToken = artifacts.require("test/XYZToken");
 const MiniToken = artifacts.require("test/MiniToken");
 const MaliciousToken = artifacts.require("test/MaliciousToken");
 const BSCValidatorSetTool = artifacts.require("tool/BSCValidatorSetTool");
@@ -48,6 +49,7 @@ module.exports = function(deployer, network, accounts) {
   });
   deployer.deploy(ABCToken);
   deployer.deploy(DEFToken);
+  deployer.deploy(XYZToken);
   deployer.deploy(MiniToken);
   deployer.deploy(MaliciousToken);
   deployer.deploy(MockRelayerHub);