This change takes advantage of the RawMessage type in the
encoding/json package to defer unmarshaling of all JSON-RPC values
until absolutely necessary.
This is particularly important for request passthrough when btcwallet
must ask btcd to handle a chain request for a wallet client. In the
previous code, during the marshal and unmarshal dance to set the
original client's request id in the btcd response, large JSON numbers
were being mangled to use (scientific) E notation even when they could
be represented as a integer without any loss of precision.
This change removes the three separate mutexes which used to lock an
account's wallet, tx store, and utxo store. Accounts no longer
contain any locking mechanism and rely on go's other synchronization
constructs (goroutines and channels) for correct access.
All accounts are now managed as a collection through the new
AccountManager, rather than the old AccountStore. AccountManager runs
as its own goroutine to provide access to accounts.
RPC requests are now queued for handling, being denied if the queue
buffer is exhausted. Notifications are also queued (instead of being
sent from their own goroutine after being received, in which order is
undefined), however, notifications are never dropped and will
potentially grow a queue of infinite size if unhandled.
This change greatly cleans up the RPC connection between btcwallet and
btcd. Proper (JSON-RPC spec-following) notifications are now expected
rather than Responses with a non-empty IDs.
A new RPCConn interface type has also been introduced with a
BtcdRPCConn concrete type for btcd RPC connections. Non-btcd-specific
code handles the RPCConn, while the btcd details have been abstracted
away to a handful of functions. This will make it easier to write
tests by creating a new fake RPC connection with hardcoded expected
replies.
