Add a new PAYMENT_ACK message to the protocol. Make incrementPayment return a future that completes when the server has acknowledge the balance increase.
Also, prevent users from overlapping multiple increase payment requests.
This resolves race conditions that can occur when the billed-for activity is asynchronous to the protocol in which the micropayment protocol is embedded. In this case, it was previously impossible to know when the async activity could be resumed as it would otherwise race with the process of the server checking the payment signature and updating the balance. Most applications of micropayments will use a single protocol that has been extended with an embedding, and thus this is not an issue. However in some rare applications the payment process may run alongside the existing protocol rather than inside it. In this case, payment acks should be used for synchronization.
1) TX confidence listeners were being run for chain height changes, even if they were not confirmed yet.
2) req.fee was being miscalculated for empty wallet transactions.
Backport misc improvements from PayFile.
Refactor the clickable address out into a custom widget.
Use FontAwesome and the wrapper class for icons instead of a custom image.
QRcode support.
Previously the PeerGroup itself would broadcast the pending transactions by simply sending an inv with them all to every peer. This is a good way to get a transaction blasted out if there are no problems with it, but it means we cannot track propagation and the numBroadcastPeers() value was correspondingly not increased. This seems to be causing issues with the Android wallet. So try out a different approach - have the wallet use broadcastTransaction as per normal on the PeerGroup when it's added. The TX will be propagated and watched as with a normal spend.
This resolves some complicated state management issues in some kinds of client (like on Android). It's also just generally a part of the work to divorce the notion of settling a channel from closing underlying protocol connections.
The client now has a new CLOSED state, which is entered once a CLOSE has been sent and the close transaction (final contract) has been broadcast onto the P2P network and entered the wallet. Once received, the hash of the close tx is stored in the wallet - the tx is itself already in the wallets spent pool because it connects to the output of the multisig tx. After seeing three confirmations of the close TX the state is deleted from the client wallet for good.
Together these changes resolve a bug/design issue in which if a channel was opened, then closed, then another channel was opened but not closed, then a third attempt to connect to the server was made, the client would try to resume the first closed channel. That would fail because the server already deleted its state object and result in new channels being created even though the second could have been resumed. By tracking the fact that the channel was closed, it can be skipped when considering what channel to resume.
