Merge pull request #600 from tokencard/inheritable-init-pattern

ENS registry/node init pattern

Author: i-stam

contracts/externals/upgradeability/UpgradeabilityProxy.sol

@@ -23,5 +23,6 @@ contract UpgradeabilityProxy is BaseUpgradeabilityProxy {
       (bool success,) = _logic.delegatecall(_data);
       require(success);
     }
-  }  
+  }
+
 }

contracts/internals/ensResolvable.sol

@@ -26,8 +26,8 @@ import "../externals/ens/PublicResolver.sol";
 ///@title ENSResolvable - Ethereum Name Service Resolver
 ///@notice contract should be used to get an address for an ENS node
 contract ENSResolvable is Initializable {
-    /// @notice _ensRegistry points to the ENS registry smart contract.
-    address private _ensRegistry;
+    /// @notice Address of the ENS registry contract set to the default ENS registry address.
+    address private _ensRegistry = address(0x00000000000C2E074eC69A0dFb2997BA6C7d2e1e);
 
     /// @notice Checks if the contract has been initialized succesfully i.e. the ENS registry has been set.
     modifier initialized() {
@@ -49,7 +49,9 @@ contract ENSResolvable is Initializable {
 
     /// @param _ensReg is the ENS registry used
     function _initializeENSResolvable(address _ensReg) internal initializer {
-        require(_ensReg != address(0), "ensReg is 0");
-        _ensRegistry = _ensReg;
+        // Set ENS registry or use default
+        if (_ensReg != address(0)) {
+            _ensRegistry = _ensReg;
+        }
     }
 }

contracts/internals/tokenWhitelistable.sol

@@ -25,8 +25,11 @@ import "../externals/initializable.sol";
 
 /// @title TokenWhitelistable implements access to the TokenWhitelist located behind ENS.
 contract TokenWhitelistable is ENSResolvable {
-    /// @notice Is the registered ENS node identifying the tokenWhitelist contract
-    bytes32 private _tokenWhitelistNode;
+    // token-whitelist.tokencard.eth
+    bytes32 private constant _DEFAULT_TOKEN_WHITELIST_NODE = 0xe84f90570f13fe09f288f2411ff9cf50da611ed0c7db7f73d48053ffc974d396;
+
+    /// @notice This is the registered ENS node identifying the tokenWhitelist contract
+    bytes32 private _tokenWhitelistNode = _DEFAULT_TOKEN_WHITELIST_NODE;
 
     /// @notice This shows what TokenWhitelist is being used
     /// @return TokenWhitelist's node registered in ENS.
@@ -68,7 +71,10 @@ contract TokenWhitelistable is ENSResolvable {
     /// @notice Initializes the TokenWhitelistable object.
     /// @param _tokenWhitelistNode_ is the ENS node of the TokenWhitelist.
     function _initializeTokenWhitelistable(bytes32 _tokenWhitelistNode_) internal initializer {
-        _tokenWhitelistNode = _tokenWhitelistNode_;
+        // Set tokenWhitelistNode or use default
+        if (_tokenWhitelistNode_ != bytes32(0)) {
+            _tokenWhitelistNode = _tokenWhitelistNode_;
+        }
     }
 
     /// @notice Checks whether a token is available.