genericschemeMultipleCalls - fix warnings (#787)

* fix warnings

* remove pragma experimental

Author: orenyodfat

contracts/libs/BytesLib.sol

@@ -0,0 +1,79 @@
+/*
+ * @title Solidity Bytes Arrays Utils
+ * @author Gonçalo Sá <goncalo.sa@consensys.net>
+ *
+ * @dev Bytes tightly packed arrays utility library for ethereum contracts written in Solidity.
+ *      The library lets you concatenate, slice and type cast bytes arrays both in memory and storage.
+ */
+
+pragma solidity 0.5.17;
+
+
+library BytesLib {
+
+    function slice(
+        bytes memory _bytes,
+        uint _start,
+        uint _length
+    )
+        internal
+        pure
+        returns (bytes memory)
+    // solhint-disable-next-line function-max-lines
+    {
+        require(_bytes.length >= (_start + _length));
+
+        bytes memory tempBytes;
+        // solhint-disable-next-line no-inline-assembly
+        assembly {
+            switch iszero(_length)
+            case 0 {
+                // Get a location of some free memory and store it in tempBytes as
+                // Solidity does for memory variables.
+                tempBytes := mload(0x40)
+
+                // The first word of the slice result is potentially a partial
+                // word read from the original array. To read it, we calculate
+                // the length of that partial word and start copying that many
+                // bytes into the array. The first word we copy will start with
+                // data we don't care about, but the last `lengthmod` bytes will
+                // land at the beginning of the contents of the new array. When
+                // we're done copying, we overwrite the full first word with
+                // the actual length of the slice.
+                let lengthmod := and(_length, 31)
+
+                // The multiplication in the next line is necessary
+                // because when slicing multiples of 32 bytes (lengthmod == 0)
+                // the following copy loop was copying the origin's length
+                // and then ending prematurely not copying everything it should.
+                let mc := add(add(tempBytes, lengthmod), mul(0x20, iszero(lengthmod)))
+                let end := add(mc, _length)
+
+                for {
+                    // The multiplication in the next line has the same exact purpose
+                    // as the one above.
+                    let cc := add(add(add(_bytes, lengthmod), mul(0x20, iszero(lengthmod))), _start)
+                } lt(mc, end) {
+                    mc := add(mc, 0x20)
+                    cc := add(cc, 0x20)
+                } {
+                    mstore(mc, mload(cc))
+                }
+
+                mstore(tempBytes, _length)
+
+                //update free-memory pointer
+                //allocating the array padded to 32 bytes like the compiler does now
+                mstore(0x40, and(add(mc, 31), not(31)))
+            }
+            //if we want a zero-length slice let's just return a zero-length array
+            default {
+                tempBytes := mload(0x40)
+
+                mstore(0x40, add(tempBytes, 0x20))
+            }
+        }
+
+        return tempBytes;
+    }
+}

contracts/schemes/GenericSchemeMultiCall.sol

@@ -1,21 +1,25 @@
 pragma solidity 0.5.17;
-pragma experimental ABIEncoderV2;
 
 import "@daostack/infra/contracts/votingMachines/IntVoteInterface.sol";
 import "@daostack/infra/contracts/votingMachines/ProposalExecuteInterface.sol";
 import "../votingMachines/VotingMachineCallbacks.sol";
+import "../libs/BytesLib.sol";
+
 
 /**
  * @title GenericSchemeMultiCall.
  * @dev  A scheme for proposing and executing calls to multiple arbitrary function
  * on one or multiple contracts on behalf of the organization avatar.
  */
 contract GenericSchemeMultiCall is VotingMachineCallbacks, ProposalExecuteInterface {
+    using BytesLib for bytes;
+    using SafeMath for uint256;
 
     // Details of a voting proposal:
     struct MultiCallProposal {
         address[] contractsToCall;
-        bytes[] callsData;
+        bytes callsData;
+        uint256[] callsDataLens;
         uint256[] values;
         bool exist;
         bool passed;
@@ -32,7 +36,7 @@ contract GenericSchemeMultiCall is VotingMachineCallbacks, ProposalExecuteInterf
     event NewMultiCallProposal(
         address indexed _avatar,
         bytes32 indexed _proposalId,
-        bytes[]   _callsData,
+        bytes   _callsData,
         uint256[] _values,
         string  _descriptionHash,
         address[] _contractsToCall
@@ -47,6 +51,7 @@ contract GenericSchemeMultiCall is VotingMachineCallbacks, ProposalExecuteInterf
         address indexed _avatar,
         bytes32 indexed _proposalId,
         address _contractToCall,
+        bytes _callsData,
         bool _success,
         bytes _callDataReturnValue
     );
@@ -65,7 +70,7 @@ contract GenericSchemeMultiCall is VotingMachineCallbacks, ProposalExecuteInterf
      * @param _votingMachine the voting machines address to
      * @param _voteParams voting machine parameters.
      * @param _contractWhitelist the contracts the scheme is allowed to interact with
-     * 
+     *
      */
     function initialize(
         Avatar _avatar,
@@ -85,7 +90,7 @@ contract GenericSchemeMultiCall is VotingMachineCallbacks, ProposalExecuteInterf
         Controller controller = Controller(_avatar.owner());
         whitelistedContracts.push(address(controller));
         contractWhitelist[address(controller)] = true;
-        
+
         for (uint i = 0; i < _contractWhitelist.length; i++) {
             contractWhitelist[_contractWhitelist[i]] = true;
             whitelistedContracts.push(_contractWhitelist[i]);
@@ -130,27 +135,30 @@ contract GenericSchemeMultiCall is VotingMachineCallbacks, ProposalExecuteInterf
         bytes memory genericCallReturnValue;
         bool success;
         Controller controller = Controller(whitelistedContracts[0]);
+        uint256 startIndex = 0;
 
         for (uint i = 0; i < proposal.contractsToCall.length; i++) {
+            bytes memory callData = proposal.callsData.slice(startIndex, proposal.callsDataLens[i]);
             if (proposal.contractsToCall[i] == address(controller)) {
                 (IERC20 extToken,
                 address spender,
                 uint256 valueToSpend
                 ) =
                 abi.decode(
-                    proposal.callsData[i],
+                    callData,
                     (IERC20, address, uint256)
                 );
                 (success) = controller.externalTokenApproval(extToken, spender, valueToSpend, avatar);
             } else {
                 (success, genericCallReturnValue) =
-                controller.genericCall(proposal.contractsToCall[i], proposal.callsData[i], avatar, proposal.values[i]);
+                controller.genericCall(proposal.contractsToCall[i], callData, avatar, proposal.values[i]);
             }
-         
+            startIndex = startIndex.add(proposal.callsDataLens[i]);
             emit ProposalCallExecuted(
                 address(avatar),
                 _proposalId,
                 proposal.contractsToCall[i],
+                callData,
                 success,
                 genericCallReturnValue
             );
@@ -164,47 +172,51 @@ contract GenericSchemeMultiCall is VotingMachineCallbacks, ProposalExecuteInterf
     /**
     * @dev propose to call one or multiple contracts on behalf of the _avatar
     *      The function trigger NewMultiCallProposal event
-    * @param _contractsToCall the contracts to be called 
+    * @param _contractsToCall the contracts to be called
     * @param _callsData - The abi encode data for the calls
+    * @param _callsDataLens the length of each callData
     * @param _values value(ETH) to transfer with the calls
     * @param _descriptionHash proposal description hash
     * @return an id which represents the proposal
     */
     function proposeCalls(
         address[] memory _contractsToCall,
-        bytes[] memory _callsData,
+        bytes memory _callsData,
+        uint256[] memory _callsDataLens,
         uint256[] memory _values,
         string memory _descriptionHash
     )
     public
     returns(bytes32 proposalId)
     {
         require(
-            (_contractsToCall.length == _callsData.length) && (_contractsToCall.length == _values.length),
-            "Wrong length of _contractsToCall, _callsData or _values arrays"
+            (_contractsToCall.length == _callsDataLens.length) && (_contractsToCall.length == _values.length),
+            "Wrong length of _contractsToCall, _callsDataLens or _values arrays"
         );
         Controller controller = Controller(whitelistedContracts[0]);
+        uint256 startIndex = 0;
         for (uint i = 0; i < _contractsToCall.length; i++) {
             require(
                 contractWhitelist[_contractsToCall[i]], "contractToCall is not whitelisted"
             );
             if (_contractsToCall[i] == address(controller)) {
-                (IERC20 extToken,
-                address spender,
-                uint256 valueToSpend
-                ) =
+
+                bytes memory callData = _callsData.slice(startIndex, _callsDataLens[i]);
+                (, address spender,) =
                 abi.decode(
-                    _callsData[i],
+                    callData,
                     (IERC20, address, uint256)
                 );
                 require(contractWhitelist[spender], "spender contract not whitelisted");
             }
+            startIndex = startIndex.add(_callsDataLens[i]);
         }
         proposalId = votingMachine.propose(2, voteParams, msg.sender, address(avatar));
 
         proposals[proposalId] = MultiCallProposal({
             contractsToCall: _contractsToCall,
             callsData: _callsData,
+            callsDataLens: _callsDataLens,
             values: _values,
             exist: true,
             passed: false
@@ -217,4 +229,4 @@ contract GenericSchemeMultiCall is VotingMachineCallbacks, ProposalExecuteInterf
         emit NewMultiCallProposal(address(avatar), proposalId, _callsData, _values, _descriptionHash, _contractsToCall);
 
     }
-}
+}