orchestrator.sol

pragma solidity >=0.4.24;

import "openzeppelin-eth/contracts/ownership/Ownable.sol";
import "./dollarsPolicy.sol";

/*
 *  Orchestrator
 */


contract Orchestrator is Ownable {

    struct Transaction {
        bool enabled;
        address destination;
        bytes data;
    }

    event TransactionFailed(address indexed destination, uint index, bytes data);

    Transaction[] public transactions;

    DollarsPolicy public policy;

    constructor(address policy_) public {
        Ownable.initialize(msg.sender);
        policy = DollarsPolicy(policy_);
    }

    function rebase()
        external
    {
        require(msg.sender == tx.origin);  // solhint-disable-line avoid-tx-origin

        policy.rebase();

        for (uint i = 0; i < transactions.length; i++) {
            Transaction storage t = transactions[i];
            if (t.enabled) {
                bool result =
                    externalCall(t.destination, t.data);
                if (!result) {
                    emit TransactionFailed(t.destination, i, t.data);
                    revert("Transaction Failed");
                }
            }
        }
    }

    function addTransaction(address destination, bytes data)
        external
        onlyOwner
    {
        transactions.push(Transaction({
            enabled: true,
            destination: destination,
            data: data
        }));
    }

    function removeTransaction(uint index)
        external
        onlyOwner
    {
        require(index < transactions.length, "index out of bounds");

        if (index < transactions.length - 1) {
            transactions[index] = transactions[transactions.length - 1];
        }

        transactions.length--;
    }

    function setTransactionEnabled(uint index, bool enabled)
        external
        onlyOwner
    {
        require(index < transactions.length, "index must be in range of stored tx list");
        transactions[index].enabled = enabled;
    }

    function transactionsSize()
        external
        view
        returns (uint256)
    {
        return transactions.length;
    }

    function externalCall(address destination, bytes data)
        internal
        returns (bool)
    {
        bool result;
        assembly {  // solhint-disable-line no-inline-assembly
            // "Allocate" memory for output
            // (0x40 is where "free memory" pointer is stored by convention)
            let outputAddress := mload(0x40)

            // First 32 bytes are the padded length of data, so exclude that
            let dataAddress := add(data, 32)

            result := call(
                // 34710 is the value that solidity is currently emitting
                // It includes callGas (700) + callVeryLow (3, to pay for SUB)
                // + callValueTransferGas (9000) + callNewAccountGas
                // (25000, in case the destination address does not exist and needs creating)
                sub(gas, 34710),


                destination,
                0, // transfer value in wei
                dataAddress,
                mload(data),  // Size of the input, in bytes. Stored in position 0 of the array.
                outputAddress,
                0  // Output is ignored, therefore the output size is zero
            )
        }
        return result;
    }
}