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ExchangeUpgradability.sol
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ExchangeUpgradability.sol
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pragma solidity >=0.4.22 <0.6.0;
import "openzeppelin-solidity/contracts/token/ERC20/SafeERC20.sol";
import "openzeppelin-solidity/contracts/math/SafeMath.sol";
import "openzeppelin-solidity/contracts/ownership/Ownable.sol";
import "./ExchangeStorage.sol";
import "./interfaces/IExchangeUpgradability.sol";
contract ExchangeUpgradability is Ownable, ExchangeStorage {
using SafeERC20 for IERC20;
using SafeMath for uint256;
/**
* @dev version of the exchange
*/
uint8 constant public VERSION = 1;
/**
* @dev the address of the upgraded exchange contract
*/
address public newExchange;
/**
* @dev flag to allow migrating to an upgraded contract
*/
bool public migrationAllowed;
/**
* @dev emitted when funds are migrated
*/
event FundsMigrated(address indexed user, address indexed newExchange);
/**
* @dev Owner can set the address of the new version of the exchange contract.
*/
function setNewExchangeAddress(address exchange)
external
onlyOwner
{
newExchange = exchange;
}
/**
* @dev Enables/Disables the migrations. Can be called only by the owner.
*/
function allowOrRestrictMigrations()
external
onlyOwner
{
migrationAllowed = !migrationAllowed;
}
/**
* @dev Migrating assets of the caller to the new exchange contract
*/
function migrateFunds(address[] calldata tokens) external {
require(
false != migrationAllowed,
"MIGRATIONS_DISALLOWED"
);
require(
IExchangeUpgradability(newExchange).VERSION() > VERSION,
"INVALID_VERSION"
);
migrateEthers();
migrateTokens(tokens);
emit FundsMigrated(msg.sender, newExchange);
}
/**
* @dev Helper function to migrate user's Ethers. Should be called in migrateFunds() function.
*/
function migrateEthers() private {
address user = msg.sender;
uint256 etherAmount = balances[address(0x0)][user];
if (etherAmount > 0) {
balances[address(0x0)][user] = 0;
IExchangeUpgradability(newExchange).importEthers.value(etherAmount)(user);
}
}
/**
* @dev Helper function to migrate user's tokens. Should be called in migrateFunds() function.
*/
function migrateTokens(address[] memory tokens) private {
address user = msg.sender;
address exchange = newExchange;
for (uint256 index = 0; index < tokens.length; index++) {
address tokenAddress = tokens[index];
uint256 tokenAmount = balances[tokenAddress][user];
if (0 == tokenAmount) {
continue;
}
IERC20(tokenAddress).safeApprove(exchange, tokenAmount);
balances[tokenAddress][user] = 0;
IExchangeUpgradability(exchange).importTokens(tokenAddress, tokenAmount, user);
}
}
/**
* @dev Helper function to migrate user's Ethers. Should be called only from the new exchange contract.
*/
function importEthers(address user)
external
payable
{
require(
false != migrationAllowed,
"MIGRATION_DISALLOWED"
);
require(
user != address(0x0),
"INVALID_USER"
);
require(
msg.value > 0,
"INVALID_AMOUNT"
);
require(
IExchangeUpgradability(msg.sender).VERSION() < VERSION,
"INVALID_VERSION"
);
balances[address(0x0)][user] = balances[address(0x0)][user].add(msg.value); // todo: constants
}
/**
* @dev Helper function to migrate user's Tokens. Should be called only from the new exchange contract.
*/
function importTokens(
address token,
uint256 amount,
address user
)
external
{
require(
false != migrationAllowed,
"MIGRATION_DISALLOWED"
);
require(
token != address(0x0),
"INVALID_TOKEN"
);
require(
user != address(0x0),
"INVALID_USER"
);
require(
amount > 0,
"INVALID_AMOUNT"
);
require(
IExchangeUpgradability(msg.sender).VERSION() < VERSION,
"INVALID_VERSION"
);
IERC20(token).safeTransferFrom(msg.sender, address(this), amount);
balances[token][user] = balances[token][user].add(amount);
}
}