medium-auction-contract-6.sol

medium-auction-contract-6.sol

function placeBid()
    payable
    onlyAfterStart
    onlyBeforeEnd
    onlyNotCanceled
    onlyNotOwner
    returns (bool success)
{
    // reject payments of 0 ETH
    if (msg.value == 0) throw;

    // calculate the user's total bid based on the current amount they've sent to the contract
    // plus whatever has been sent with this transaction
    uint newBid = fundsByBidder[msg.sender] + msg.value;

    // if the user isn't even willing to overbid the highest binding bid, there's nothing for us
    // to do except revert the transaction.
    if (newBid <= highestBindingBid) throw;

    // grab the previous highest bid (before updating fundsByBidder, in case msg.sender is the
    // highestBidder and is just increasing their maximum bid).
    uint highestBid = fundsByBidder[highestBidder];

    fundsByBidder[msg.sender] = newBid;

    if (newBid <= highestBid) {
        // if the user has overbid the highestBindingBid but not the highestBid, we simply
        // increase the highestBindingBid and leave highestBidder alone.

        // note that this case is impossible if msg.sender == highestBidder because you can never
        // bid less ETH than you already have.

        highestBindingBid = min(newBid + bidIncrement, highestBid);
    } else {
        // if msg.sender is already the highest bidder, they must simply be wanting to raise
        // their maximum bid, in which case we shouldn't increase the highestBindingBid.

        // if the user is NOT highestBidder, and has overbid highestBid completely, we set them
        // as the new highestBidder and recalculate highestBindingBid.

        if (msg.sender != highestBidder) {
            highestBidder = msg.sender;
            highestBindingBid = min(newBid, highestBid + bidIncrement);
        }
        highestBid = newBid;
    }

    LogBid(msg.sender, newBid, highestBidder, highestBid, highestBindingBid);
    return true;
}