update DappLogic with multi-contract calling

contracts/logics/DappLogic.sol

@@ -1,9 +1,12 @@
 pragma solidity ^0.5.4;
 
 import "./base/BaseLogic.sol";
+import "../utils/RLPReader.sol";
 
 contract DappLogic is BaseLogic {
 
+    using RLPReader for RLPReader.RLPItem;
+    using RLPReader for bytes;
     /*
     index 0: admin key
           1: asset(transfer)
@@ -60,5 +63,22 @@ contract DappLogic is BaseLogic {
         require(success, "calling invoke failed");
     }
 
+    // called from 'enter'
+    // call serveral other contracts at a time
+    // rlp encode _methodData array into rlpBytes
+    function callMultiContract(address payable _account, address[] calldata _targets, uint256[] calldata _values, bytes calldata _rlpBytes) external allowSelfCallsOnly {
+        RLPReader.RLPItem[] memory ls = _rlpBytes.toRlpItem().toList();
+
+        uint256 len = _targets.length;
+        require(len == _values.length && len == ls.length, "length mismatch");
+        for (uint256 i = 0; i < len; i++) {
+            bool success;
+            RLPReader.RLPItem memory item = ls[i];
+            // solium-disable-next-line security/no-low-level-calls
+            (success,) = _account.call(abi.encodeWithSignature("invoke(address,uint256,bytes)", _targets[i], _values[i], bytes(item.toBytes())));
+            require(success, "calling invoke failed");
+        }
+    }
+
 }
 

contracts/utils/RLPReader.sol

@@ -0,0 +1,310 @@
+
+//https://github.com/hamdiallam/Solidity-RLP/blob/master/contracts/RLPReader.sol
+
+pragma solidity ^0.5.4;
+
+library RLPReader {
+    uint8 constant STRING_SHORT_START = 0x80;
+    uint8 constant STRING_LONG_START  = 0xb8;
+    uint8 constant LIST_SHORT_START   = 0xc0;
+    uint8 constant LIST_LONG_START    = 0xf8;
+    uint8 constant WORD_SIZE = 32;
+
+    struct RLPItem {
+        uint len;
+        uint memPtr;
+    }
+
+    struct Iterator {
+        RLPItem item;   // Item that's being iterated over.
+        uint nextPtr;   // Position of the next item in the list.
+    }
+
+    /*
+    * @dev Returns the next element in the iteration. Reverts if it has not next element.
+    * @param self The iterator.
+    * @return The next element in the iteration.
+    */
+    function next(Iterator memory self) internal pure returns (RLPItem memory) {
+        require(hasNext(self));
+
+        uint ptr = self.nextPtr;
+        uint itemLength = _itemLength(ptr);
+        self.nextPtr = ptr + itemLength;
+
+        return RLPItem(itemLength, ptr);
+    }
+
+    /*
+    * @dev Returns true if the iteration has more elements.
+    * @param self The iterator.
+    * @return true if the iteration has more elements.
+    */
+    function hasNext(Iterator memory self) internal pure returns (bool) {
+        RLPItem memory item = self.item;
+        return self.nextPtr < item.memPtr + item.len;
+    }
+
+    /*
+    * @param item RLP encoded bytes
+    */
+    function toRlpItem(bytes memory item) internal pure returns (RLPItem memory) {
+        uint memPtr;
+        assembly {
+            memPtr := add(item, 0x20)
+        }
+
+        return RLPItem(item.length, memPtr);
+    }
+
+    /*
+    * @dev Create an iterator. Reverts if item is not a list.
+    * @param self The RLP item.
+    * @return An 'Iterator' over the item.
+    */
+    function iterator(RLPItem memory self) internal pure returns (Iterator memory) {
+        require(isList(self));
+
+        uint ptr = self.memPtr + _payloadOffset(self.memPtr);
+        return Iterator(self, ptr);
+    }
+
+    /*
+    * @param item RLP encoded bytes
+    */
+    function rlpLen(RLPItem memory item) internal pure returns (uint) {
+        return item.len;
+    }
+
+    /*
+    * @param item RLP encoded bytes
+    */
+    function payloadLen(RLPItem memory item) internal pure returns (uint) {
+        return item.len - _payloadOffset(item.memPtr);
+    }
+
+    /*
+    * @param item RLP encoded list in bytes
+    */
+    function toList(RLPItem memory item) internal pure returns (RLPItem[] memory) {
+        require(isList(item));
+
+        uint items = numItems(item);
+        RLPItem[] memory result = new RLPItem[](items);
+
+        uint memPtr = item.memPtr + _payloadOffset(item.memPtr);
+        uint dataLen;
+        for (uint i = 0; i < items; i++) {
+            dataLen = _itemLength(memPtr);
+            result[i] = RLPItem(dataLen, memPtr); 
+            memPtr = memPtr + dataLen;
+        }
+
+        return result;
+    }
+
+    // @return indicator whether encoded payload is a list. negate this function call for isData.
+    function isList(RLPItem memory item) internal pure returns (bool) {
+        if (item.len == 0) return false;
+
+        uint8 byte0;
+        uint memPtr = item.memPtr;
+        assembly {
+            byte0 := byte(0, mload(memPtr))
+        }
+
+        if (byte0 < LIST_SHORT_START)
+            return false;
+        return true;
+    }
+
+    /** RLPItem conversions into data types **/
+
+    // @returns raw rlp encoding in bytes
+    function toRlpBytes(RLPItem memory item) internal pure returns (bytes memory) {
+        bytes memory result = new bytes(item.len);
+        if (result.length == 0) return result;
+
+        uint ptr;
+        assembly {
+            ptr := add(0x20, result)
+        }
+
+        copy(item.memPtr, ptr, item.len);
+        return result;
+    }
+
+    // any non-zero byte is considered true
+    function toBoolean(RLPItem memory item) internal pure returns (bool) {
+        require(item.len == 1);
+        uint result;
+        uint memPtr = item.memPtr;
+        assembly {
+            result := byte(0, mload(memPtr))
+        }
+
+        return result == 0 ? false : true;
+    }
+
+    function toAddress(RLPItem memory item) internal pure returns (address) {
+        // 1 byte for the length prefix
+        require(item.len == 21);
+
+        return address(toUint(item));
+    }
+
+    function toUint(RLPItem memory item) internal pure returns (uint) {
+        require(item.len > 0 && item.len <= 33);
+
+        uint offset = _payloadOffset(item.memPtr);
+        uint len = item.len - offset;
+
+        uint result;
+        uint memPtr = item.memPtr + offset;
+        assembly {
+            result := mload(memPtr)
+
+            // shfit to the correct location if neccesary
+            if lt(len, 32) {
+                result := div(result, exp(256, sub(32, len)))
+            }
+        }
+
+        return result;
+    }
+
+    // enforces 32 byte length
+    function toUintStrict(RLPItem memory item) internal pure returns (uint) {
+        // one byte prefix
+        require(item.len == 33);
+
+        uint result;
+        uint memPtr = item.memPtr + 1;
+        assembly {
+            result := mload(memPtr)
+        }
+
+        return result;
+    }
+
+    function toBytes(RLPItem memory item) internal pure returns (bytes memory) {
+        require(item.len > 0);
+
+        uint offset = _payloadOffset(item.memPtr);
+        uint len = item.len - offset; // data length
+        bytes memory result = new bytes(len);
+
+        uint destPtr;
+        assembly {
+            destPtr := add(0x20, result)
+        }
+
+        copy(item.memPtr + offset, destPtr, len);
+        return result;
+    }
+
+    /*
+    * Private Helpers
+    */
+
+    // @return number of payload items inside an encoded list.
+    function numItems(RLPItem memory item) private pure returns (uint) {
+        if (item.len == 0) return 0;
+
+        uint count = 0;
+        uint currPtr = item.memPtr + _payloadOffset(item.memPtr);
+        uint endPtr = item.memPtr + item.len;
+        while (currPtr < endPtr) {
+           currPtr = currPtr + _itemLength(currPtr); // skip over an item
+           count++;
+        }
+
+        return count;
+    }
+
+    // @return entire rlp item byte length
+    function _itemLength(uint memPtr) private pure returns (uint) {
+        uint itemLen;
+        uint byte0;
+        assembly {
+            byte0 := byte(0, mload(memPtr))
+        }
+
+        if (byte0 < STRING_SHORT_START)
+            itemLen = 1;
+
+        else if (byte0 < STRING_LONG_START)
+            itemLen = byte0 - STRING_SHORT_START + 1;
+
+        else if (byte0 < LIST_SHORT_START) {
+            assembly {
+                let byteLen := sub(byte0, 0xb7) // # of bytes the actual length is
+                memPtr := add(memPtr, 1) // skip over the first byte
+
+                /* 32 byte word size */
+                let dataLen := div(mload(memPtr), exp(256, sub(32, byteLen))) // right shifting to get the len
+                itemLen := add(dataLen, add(byteLen, 1))
+            }
+        }
+
+        else if (byte0 < LIST_LONG_START) {
+            itemLen = byte0 - LIST_SHORT_START + 1;
+        } 
+
+        else {
+            assembly {
+                let byteLen := sub(byte0, 0xf7)
+                memPtr := add(memPtr, 1)
+
+                let dataLen := div(mload(memPtr), exp(256, sub(32, byteLen))) // right shifting to the correct length
+                itemLen := add(dataLen, add(byteLen, 1))
+            }
+        }
+
+        return itemLen;
+    }
+
+    // @return number of bytes until the data
+    function _payloadOffset(uint memPtr) private pure returns (uint) {
+        uint byte0;
+        assembly {
+            byte0 := byte(0, mload(memPtr))
+        }
+
+        if (byte0 < STRING_SHORT_START) 
+            return 0;
+        else if (byte0 < STRING_LONG_START || (byte0 >= LIST_SHORT_START && byte0 < LIST_LONG_START))
+            return 1;
+        else if (byte0 < LIST_SHORT_START)  // being explicit
+            return byte0 - (STRING_LONG_START - 1) + 1;
+        else
+            return byte0 - (LIST_LONG_START - 1) + 1;
+    }
+
+    /*
+    * @param src Pointer to source
+    * @param dest Pointer to destination
+    * @param len Amount of memory to copy from the source
+    */
+    function copy(uint src, uint dest, uint len) private pure {
+        if (len == 0) return;
+
+        // copy as many word sizes as possible
+        for (; len >= WORD_SIZE; len -= WORD_SIZE) {
+            assembly {
+                mstore(dest, mload(src))
+            }
+
+            src += WORD_SIZE;
+            dest += WORD_SIZE;
+        }
+
+        // left over bytes. Mask is used to remove unwanted bytes from the word
+        uint mask = 256 ** (WORD_SIZE - len) - 1;
+        assembly {
+            let srcpart := and(mload(src), not(mask)) // zero out src
+            let destpart := and(mload(dest), mask) // retrieve the bytes
+            mstore(dest, or(destpart, srcpart))
+        }
+    }
+}