The synchronizer's work is done from the network proxy's main loop.
A minor problem with the old synchronizer was that it considered itself
out of date if the network was out of date. This was too generic: the
network can have pending requests unrelated to the synchronizer. This
resulted in the synchronizer often unnecessarily flipping the wallet
between up-to-date and not-up-to-date, and causing unnecessary calls
to wallet.save_transactions(). This was observable when opening the
network dialog box: frequently just opening it would cause a wallet
status change and transaction flush, simply because the network dialog
sends a get_parameters() request. This rework of the synchronizer does
not have that issue.
Two callers of get_spendable_coins were removing frozen addrs
before calling. Put that functionality in the function.
We shouldn't be able to send_from a frozen address. This was
possible in the current release because logic assumed a two-element
tuple was returned when it is now three-element. Fix that too.
Command line options listunspent and createrawtransaction currently
ignore frozen addresses. I'm not sure that's right but I've preserved
that behaviour.
With this patch only the wallet class refers to self.frozen_addresses;
other clients use is_frozen() now.
Speedup mainly from writing to storage only once.
Make frozen_addresses a set in memory, as sets give cleaner
code and are more efficient.
Minor change in behaviour: command line freezing used to return
False if the address isn't in the wallet OR the address was already
frozen. Now it returns more like a success code: it returns False
only if the address isn't in the wallet regardless of frozen state.
Similarly for unfreezing.
As discussed on #electrum yesterday.
Increase change gap limit to 6.
Choose the next unused change address, if any, otherwise pick
one at random from the gap limit.
